Panel_14414 Panel_14414 8:30 AM 5:00 PM

Sedimentology, stratigraphy, spatial distribution, and temporal evolution of mass transport complexes (MTCs) and turbidites in lacustrine rift basins are complex, because of highly variable accommodation space, frequent lake level fluctuations, and short sediment transport distance in small drainage basins. These gravity deposits are significant components of basin fills at steep margins, but rarely documented in the subsurface. MTCs and turbidites are interpreted in 7 syn-rift sequences in Paleogene lacustrine deposits, Minfeng half graben, Bohai Bay Basin, using core, log, and 3-D seismic data. MTCs are composed of 0.1-10s m thick conglomerate and sandstone units intercalated with dark-gray shales, reflecting parent rocks. They have blocky log patterns of low acoustic and neutron, and high gamma-ray and resistivity values. MTCs are faulted and folded, and show chaotic, discontinuous, and randomly-oriented seismic reflections of variable amplitude, indicating a contorted nature. Individual reflections are 100s m long and 10s m thick, as mass-transport blocks. The MTCs are ~200 m thick, 2.5 km long, and wedge-shaped with a convex top and a fairly flat base in dip sections and a mounded shape in strike sections. They are located at the toe of a concave escarpment. The above features suggest that slumping had occurred along the escarpment and deposited MTCs downslope. The other sediment gravity deposits at the steep margin occur as coarse-grained turbidites. They are upward-fining successions and 0.01-1 m thick; and contain conglomerate and sandstone capped by thin shale. Beds are massive, graded, planar, or cross-stratified with a sharp or erosional base and a gradational top. The turbidites have similar log patterns to MTCs. However, they comprise fan complexes, showing different seismic facies as continuous to discontinuous, progradational clinoforms with intermediate amplitude. Laterally persistent shale and evaporite onlap the fan outer boundaries. The fan complexes occur at the mouths of gullies and valleys, and are separated by ridges, indicating syn-depositional topographic control on fan development. At a sequence scale, turbidite fans are progradational or retrogradational, whereas MTCs do not show a systematic pattern. The results demonstrate the diversity and complexity of gravity-driven deposits in ancient lacustrine basins. Sedimentology, stratigraphy, spatial distribution, and temporal evolution of mass transport complexes (MTCs) and turbidites in lacustrine rift basins are complex, because of highly variable accommodation space, frequent lake level fluctuations, and short sediment transport distance in small drainage basins. These gravity deposits are significant components of basin fills at steep margins, but rarely documented in the subsurface. MTCs and turbidites are interpreted in 7 syn-rift sequences in Paleogene lacustrine deposits, Minfeng half graben, Bohai Bay Basin, using core, log, and 3-D seismic data. MTCs are composed of 0.1-10s m thick conglomerate and sandstone units intercalated with dark-gray shales, reflecting parent rocks. They have blocky log patterns of low acoustic and neutron, and high gamma-ray and resistivity values. MTCs are faulted and folded, and show chaotic, discontinuous, and randomly-oriented seismic reflections of variable amplitude, indicating a contorted nature. Individual reflections are 100s m long and 10s m thick, as mass-transport blocks. The MTCs are ~200 m thick, 2.5 km long, and wedge-shaped with a convex top and a fairly flat base in dip sections and a mounded shape in strike sections. They are located at the toe of a concave escarpment. The above features suggest that slumping had occurred along the escarpment and deposited MTCs downslope. The other sediment gravity deposits at the steep margin occur as coarse-grained turbidites. They are upward-fining successions and 0.01-1 m thick; and contain conglomerate and sandstone capped by thin shale. Beds are massive, graded, planar, or cross-stratified with a sharp or erosional base and a gradational top. The turbidites have similar log patterns to MTCs. However, they comprise fan complexes, showing different seismic facies as continuous to discontinuous, progradational clinoforms with intermediate amplitude. Laterally persistent shale and evaporite onlap the fan outer boundaries. The fan complexes occur at the mouths of gullies and valleys, and are separated by ridges, indicating syn-depositional topographic control on fan development. At a sequence scale, turbidite fans are progradational or retrogradational, whereas MTCs do not show a systematic pattern. The results demonstrate the diversity and complexity of gravity-driven deposits in ancient lacustrine basins. Panel_14786 Panel_14786 8:30 AM 5:00 PM

Syndepositional deformation features are fundamental components of carbonate platforms both in the subsurface and in seismic-scale field analogs. These deformation features are commonly opening-mode, solution-widened fractures that can evolve into extensional faults, and reactivate frequently through the evolution of the platform. They also have potential to act as fluid flow conduits from the earliest phases of platform growth through burial and uplift, and are present during hydrocarbon generation. As such, diagenetic alteration in the margins of these carbonate platforms is often intense, may demonstrate a preferential spatial relationship to the deformation features rather than the depositional fabrics of the strata, and may impact the permeability development of reservoir strata near deformation features. This study investigates the distribution of 2 generations of dolomite in the Permian Yates Fm. in Rattlesnake Canyon, Guadalupe Mountains, NM. The dolomites were sampled along a 1 km dip-oriented outcrop, covering two high-frequency sequences (HFSs; approx. 300ky each) and cut by a margin parallel syndepositional fault graben. 100 samples from 6 transects (3 lateral through the reef, outer-shelf, and shelf crest updip of the graben; 3 vertical from reef to shelf crest updip of the graben, downdip of the proximal fault, and across the basinal fault) were classified by petrographic, CL, and trace element data. The data show an early mimetic, dully-luminescent, aphanocrystalline dolomite attributed to brine reflux from a mid-platform lagoon; and a late fabric destructive, brightly-luminescent dolomite that is strongly associated with deformation features. The former is pervasive in the older HFS within/updip of the graben as well as in the shallowest strata downdip, while the latter utilized the permeability conduits created by faults and fractures, particularly those filled with inner platform siliciclastics, to form patchy haloes around the features. These haloes overlap to result in a dolomitized reef updip/in the graben, and fabric-destructive lenses extending from deformation features into beds of more permeable shelf strata. The geometries are consistent with a similar fault-related dolomite study in the Tansill Fm., Dark Canyon (Frost et al., 2012), though alteration is more extensive in the Rattlesnake Canyon window. In combination, these works prove that fault and fracture related diagenesis is not trivial to the evolution of platform margins. Syndepositional deformation features are fundamental components of carbonate platforms both in the subsurface and in seismic-scale field analogs. These deformation features are commonly opening-mode, solution-widened fractures that can evolve into extensional faults, and reactivate frequently through the evolution of the platform. They also have potential to act as fluid flow conduits from the earliest phases of platform growth through burial and uplift, and are present during hydrocarbon generation. As such, diagenetic alteration in the margins of these carbonate platforms is often intense, may demonstrate a preferential spatial relationship to the deformation features rather than the depositional fabrics of the strata, and may impact the permeability development of reservoir strata near deformation features. This study investigates the distribution of 2 generations of dolomite in the Permian Yates Fm. in Rattlesnake Canyon, Guadalupe Mountains, NM. The dolomites were sampled along a 1 km dip-oriented outcrop, covering two high-frequency sequences (HFSs; approx. 300ky each) and cut by a margin parallel syndepositional fault graben. 100 samples from 6 transects (3 lateral through the reef, outer-shelf, and shelf crest updip of the graben; 3 vertical from reef to shelf crest updip of the graben, downdip of the proximal fault, and across the basinal fault) were classified by petrographic, CL, and trace element data. The data show an early mimetic, dully-luminescent, aphanocrystalline dolomite attributed to brine reflux from a mid-platform lagoon; and a late fabric destructive, brightly-luminescent dolomite that is strongly associated with deformation features. The former is pervasive in the older HFS within/updip of the graben as well as in the shallowest strata downdip, while the latter utilized the permeability conduits created by faults and fractures, particularly those filled with inner platform siliciclastics, to form patchy haloes around the features. These haloes overlap to result in a dolomitized reef updip/in the graben, and fabric-destructive lenses extending from deformation features into beds of more permeable shelf strata. The geometries are consistent with a similar fault-related dolomite study in the Tansill Fm., Dark Canyon (Frost et al., 2012), though alteration is more extensive in the Rattlesnake Canyon window. In combination, these works prove that fault and fracture related diagenesis is not trivial to the evolution of platform margins. Panel_14791 Panel_14791 8:30 AM 5:00 PM

Previous studies conducted in the Victoria Land Basin (VLB), Antarctica have focused primarily on the stratigraphy, paleontology, and sedimentology of the area. Less attention has been given to the burial history of the succession, including the nature and distribution of subsurface fluids and their significance with regard to diagenesis and porosity evolution. Because of this, some aspects of the burial, structural, and hydrologic history of the VLB remain unresolved. This petrographic study documents the presence and characteristics of carbonate cement phases through the Cenozoic succession of the VLB and explores relationships between the distribution of cements and sandstone type, associated sequence stratigraphic systems tracts, depth, and paleoclimate. Point counting was conducted to determine percentages of cement, porosity, matrix, and grains. The results display a general pattern of increasing cement abundance and decreasing porosity with depth. Increasing depth also shows a pattern in cement morphologies, with poikilotopic and blocky cements more abundant below 700 mbsf. In addition, an increase in cement abundance related to these morphologies is proportional to a decrease in porosity. Porosity appears to be higher in highstand systems tract sands, whereas, lowstand systems tract lithologies tend to have porosity values less than 5%. Findings indicate that paleoclimate also plays a major role in controlling diagenesis and determining porosity values. Low porosity values due to cement occlusion occur in samples representing the coldest climate regimes, with extremely low values corresponding to Upper and Lower Miocene. Low porosity values are also attributed to an abundance of fine-grained matrix in conjunction with lesser amounts of cement in AND-2A samples representing high latitude temperate glacial regimes. High porosity values were found in deltaic sands deposited under high latitude temperate glacial regimes with distant wet-based glaciers. The highest values of porosity in AND-2A correspond to the warmest period of the Miocene. Notwithstanding processes associated with progressive burial, strong correlations between climatic regime and the distribution of porosity and cement point towards climate and sea level variations as the major controls on burial diagenetic processes. Previous studies conducted in the Victoria Land Basin (VLB), Antarctica have focused primarily on the stratigraphy, paleontology, and sedimentology of the area. Less attention has been given to the burial history of the succession, including the nature and distribution of subsurface fluids and their significance with regard to diagenesis and porosity evolution. Because of this, some aspects of the burial, structural, and hydrologic history of the VLB remain unresolved. This petrographic study documents the presence and characteristics of carbonate cement phases through the Cenozoic succession of the VLB and explores relationships between the distribution of cements and sandstone type, associated sequence stratigraphic systems tracts, depth, and paleoclimate. Point counting was conducted to determine percentages of cement, porosity, matrix, and grains. The results display a general pattern of increasing cement abundance and decreasing porosity with depth. Increasing depth also shows a pattern in cement morphologies, with poikilotopic and blocky cements more abundant below 700 mbsf. In addition, an increase in cement abundance related to these morphologies is proportional to a decrease in porosity. Porosity appears to be higher in highstand systems tract sands, whereas, lowstand systems tract lithologies tend to have porosity values less than 5%. Findings indicate that paleoclimate also plays a major role in controlling diagenesis and determining porosity values. Low porosity values due to cement occlusion occur in samples representing the coldest climate regimes, with extremely low values corresponding to Upper and Lower Miocene. Low porosity values are also attributed to an abundance of fine-grained matrix in conjunction with lesser amounts of cement in AND-2A samples representing high latitude temperate glacial regimes. High porosity values were found in deltaic sands deposited under high latitude temperate glacial regimes with distant wet-based glaciers. The highest values of porosity in AND-2A correspond to the warmest period of the Miocene. Notwithstanding processes associated with progressive burial, strong correlations between climatic regime and the distribution of porosity and cement point towards climate and sea level variations as the major controls on burial diagenetic processes. Panel_14797 Panel_14797 8:30 AM 5:00 PM

Recognizing the presence of microporosity in carbonate reservoirs is often a critical step in the characterization process. High microporosity/total porosity ratios adversely affect production rates and create zones of high water saturation and need to be fully appreciated. Microporosity is commonly associated with deep-water chalks and mudrocks; however, micropore networks can be important contributors to porosity and permeability in shallow-water carbonates as well. The Albian (Cretaceous) Word Field in Lavaca County, Texas, is a 600 BCF gas field that produces from microporous stacked subtidal cycles deposited in a lagoon behind the Stuart City Reef margin. This study aims to delineate spatial trends in micropore distribution in Word Field by integrating data from four cores and sixty thin sections with six-inch to one foot spaced core plug porosity and permeability values. Methodology includes picking depositional facies and building a sequence stratigraphic framework from 1D and 2D stacking pattern analysis. Investigation of depositional and diagenetic textures in thin section suggests that microporosity is not facies selective at Word Field, instead forming after high-magnesium calcite allochems that occur throughout the shallow-water platform interior setting. Key microporous grains include the cortices of oncoids and other microbially coated grains, including encrusting Lithocodium. Minor pore types include moldic porosity after fossils and trace interparticle porosity in lower energy peloidal facies. Comparisons of petrophysical data with the sequence stratigraphic framework at several scales suggests that relationship between microporosity and permeability is most predictable at the system tract scale within high-frequency sequences. Correlation along depositional strike among the cored intervals shows a moderate degree of heterogeneity. Additionally, lateral changes in accommodation at the system tract and sequence scales affect the thickness and frequency of different facies packages. Fully understanding the microporosity distribution involves integrating observations at the high-frequency cycle level with larger scale changes in stratigraphy throughout the field. The overall aim of the study is to improve our understanding of microporosity in shallow water carbonate and to add to our knowledge of the Stuart City trend and other Cretaceous platforms. Recognizing the presence of microporosity in carbonate reservoirs is often a critical step in the characterization process. High microporosity/total porosity ratios adversely affect production rates and create zones of high water saturation and need to be fully appreciated. Microporosity is commonly associated with deep-water chalks and mudrocks; however, micropore networks can be important contributors to porosity and permeability in shallow-water carbonates as well. The Albian (Cretaceous) Word Field in Lavaca County, Texas, is a 600 BCF gas field that produces from microporous stacked subtidal cycles deposited in a lagoon behind the Stuart City Reef margin. This study aims to delineate spatial trends in micropore distribution in Word Field by integrating data from four cores and sixty thin sections with six-inch to one foot spaced core plug porosity and permeability values. Methodology includes picking depositional facies and building a sequence stratigraphic framework from 1D and 2D stacking pattern analysis. Investigation of depositional and diagenetic textures in thin section suggests that microporosity is not facies selective at Word Field, instead forming after high-magnesium calcite allochems that occur throughout the shallow-water platform interior setting. Key microporous grains include the cortices of oncoids and other microbially coated grains, including encrusting Lithocodium. Minor pore types include moldic porosity after fossils and trace interparticle porosity in lower energy peloidal facies. Comparisons of petrophysical data with the sequence stratigraphic framework at several scales suggests that relationship between microporosity and permeability is most predictable at the system tract scale within high-frequency sequences. Correlation along depositional strike among the cored intervals shows a moderate degree of heterogeneity. Additionally, lateral changes in accommodation at the system tract and sequence scales affect the thickness and frequency of different facies packages. Fully understanding the microporosity distribution involves integrating observations at the high-frequency cycle level with larger scale changes in stratigraphy throughout the field. The overall aim of the study is to improve our understanding of microporosity in shallow water carbonate and to add to our knowledge of the Stuart City trend and other Cretaceous platforms. Panel_14782 Panel_14782 8:30 AM 5:00 PM

Discovery of the 16 TCF La Perla gas giant in 2009 was the first major carbonate-hosted giant reservoir discovered in northern South America. Moreover, the La Perla discovery was found in the northern part of the Gulf of Venezuela on the exotic Caribbean plate and did not involve the more familiar hydrocarbon habitat in Venezuela of foreland basin clastic reservoirs sourced by the Cretaceous passive margin. We describe the La Vela carbonate reservoir, offshore Falcon basin, western Venezuela, located 170 km southwest of La Perla and consisting of an Early Miocene reefal reservoir directly overlying igneous-metamorphic basement with associated Miocene age source rocks. The reservoir produces both light-medium oil and gas and more than half of the reservoir presents effective porosities between 8 and 15%, and permeabilities less than 15 mD. We used 960 km2 of 3D seismic data tied to 40 wells to map the reef reservoir facies over an area of 11000 km2. The thickness of the limestone varies from several meters to 150 m. Well data show that the facies is a shallow carbonate ramp with localized reef buildups. We use the curvature and other attributes for the seismic volume to show that variations in porosity are controlled by diagenetic effects rather than by fracturing. The level of deformation is much less than in the neighboring areas of the onland, inverted Falcon basin to the south. We have identified good seals at local and regional scales that correspond to maximum flooding shale units. We use paleogeographic maps to show a possible Miocene reefal carbonate trend running along the southern edge of the exotic Caribbean plate and linking the La Vela area to the La Perla area of the Gulf of Venezuela. Discovery of the 16 TCF La Perla gas giant in 2009 was the first major carbonate-hosted giant reservoir discovered in northern South America. Moreover, the La Perla discovery was found in the northern part of the Gulf of Venezuela on the exotic Caribbean plate and did not involve the more familiar hydrocarbon habitat in Venezuela of foreland basin clastic reservoirs sourced by the Cretaceous passive margin. We describe the La Vela carbonate reservoir, offshore Falcon basin, western Venezuela, located 170 km southwest of La Perla and consisting of an Early Miocene reefal reservoir directly overlying igneous-metamorphic basement with associated Miocene age source rocks. The reservoir produces both light-medium oil and gas and more than half of the reservoir presents effective porosities between 8 and 15%, and permeabilities less than 15 mD. We used 960 km² of 3D seismic data tied to 40 wells to map the reef reservoir facies over an area of 11000 km². The thickness of the limestone varies from several meters to 150 m. Well data show that the facies is a shallow carbonate ramp with localized reef buildups. We use the curvature and other attributes for the seismic volume to show that variations in porosity are controlled by diagenetic effects rather than by fracturing. The level of deformation is much less than in the neighboring areas of the onland, inverted Falcon basin to the south. We have identified good seals at local and regional scales that correspond to maximum flooding shale units. We use paleogeographic maps to show a possible Miocene reefal carbonate trend running along the southern edge of the exotic Caribbean plate and linking the La Vela area to the La Perla area of the Gulf of Venezuela. Panel_14784 Panel_14784 8:30 AM 5:00 PM

Permeability of sedimentary deposits varies with different facies and subfacies and is significantly affected by variations of sediment texture and fabric. However, current practical reservoir models generally resolve larger scale permeability anisotropies, which cannot fully capture the nature of permeability anisotropy, in the case of cross bedding. This research is to evaluate the relationship between permeability anisotropy and facies architectural elements of braided fluvial facies in the middle Boggy Formation (Middle Pennsylvanian, Desmoinesian Series) in the Lake Eufaula area (McIntosh County). Three fluvial storeys are recognized in the study outcrop. Six lithofacies and up to sixth order of bounding surfaces are identified based on Miall’s (1996) facies architecture scheme. Porosity of core plug samples with different lithofacies is relatively uniform (14-19%). Core plug results show relatively higher permeability values in the parallel to cross strata strike orientation than parallel to dip and perpendicular to dip orientations. Low probe permeability results are observed in this study, suggesting the unreliability for permeability anisotropy characterization. Diagenetic overprint on grain fabric and the dual pore system brings more complexity in affecting the preferred fluid flow direction in thin section examination. Micro-CT imaging provides 3-D visualization of pore networks and aids in understanding pore conductivity at the scale of core plugs. Middle Boggy braided fluvial facies architecture example demonstrates the control particular architectural elements play in permeability anisotropy and provides insights to understanding reservoir scale heterogeneity issues. Permeability of sedimentary deposits varies with different facies and subfacies and is significantly affected by variations of sediment texture and fabric. However, current practical reservoir models generally resolve larger scale permeability anisotropies, which cannot fully capture the nature of permeability anisotropy, in the case of cross bedding. This research is to evaluate the relationship between permeability anisotropy and facies architectural elements of braided fluvial facies in the middle Boggy Formation (Middle Pennsylvanian, Desmoinesian Series) in the Lake Eufaula area (McIntosh County). Three fluvial storeys are recognized in the study outcrop. Six lithofacies and up to sixth order of bounding surfaces are identified based on Miall’s (1996) facies architecture scheme. Porosity of core plug samples with different lithofacies is relatively uniform (14-19%). Core plug results show relatively higher permeability values in the parallel to cross strata strike orientation than parallel to dip and perpendicular to dip orientations. Low probe permeability results are observed in this study, suggesting the unreliability for permeability anisotropy characterization. Diagenetic overprint on grain fabric and the dual pore system brings more complexity in affecting the preferred fluid flow direction in thin section examination. Micro-CT imaging provides 3-D visualization of pore networks and aids in understanding pore conductivity at the scale of core plugs. Middle Boggy braided fluvial facies architecture example demonstrates the control particular architectural elements play in permeability anisotropy and provides insights to understanding reservoir scale heterogeneity issues. Panel_14793 Panel_14793 8:30 AM 5:00 PM

The Tres Pasos Fm of the Magallanes Basin in Chile records the evolution of a prograding deep-water slope system with exceptionally well exposed depositional dip-oriented middle to lower slope strata exposed at the Laguna Figueroa locality. The outcrop contains three channel complexes comprised of 18 channel elements. While analogous slope channel deposits can contain significant reservoir potential, their channelized nature creates uncertain connectivity, which can be problematic for efficient hydrocarbon production. This work seeks to quantify the influence of reservoir architecture on reservoir productivity as a function of well placement and inter-/intra-channel architecture using a high-resolution outcrop-based geocellular model. Reservoir flow simulation is performed to assess the impact of intra-channel architecture on production profiles. Simulated production data is analyzed to elucidate potential clues useful for predicting channel dimensions and connectivity in new and/or producing fields. Reservoir simulations were run for: 1) a single channel element and 2) sector models representing areas of vertically aligned versus laterally offset channel elements. All models were represented at a 2 m x 2 m x 0.25 m grid scale. Three primary facies associations (FA) capture the lithologies present in outcrop: FA1 (axial) – thick-bedded amalgamated sandstone (95% sandstone); FA2 (off-axis) – thick- to thin-bedded semi-amalgamated sandstone with few fine-grained interbeds (81% sandstone); FA3 (marginal) – thin-bedded fine- to very fine-grained sandstone with interbedded siltstone and mudstone (39% sandstone). Three scenarios were created to quantify the influence of reservoir architecture on productivity by varying the proportion and distribution of facies within each channel element. Scenarios capture a range of possible architectural frameworks from highly connected FA1-dominant to more compartmentalized FA2- and FA3-dominant conditions. Hydrocarbon production was simulated from a single extraction well at the axis of the channel element(s) and two water flood injectors 35 meters from the channel margins. Inter- and intra-channel connectivity were evaluated based on the volume and location of oil left in place following water breakthrough. The influence of well placement on productivity was quantified by rerunning each of the realizations with injectors rotated to the center of the channel(s) up- and down-gradient of the production well. The Tres Pasos Fm of the Magallanes Basin in Chile records the evolution of a prograding deep-water slope system with exceptionally well exposed depositional dip-oriented middle to lower slope strata exposed at the Laguna Figueroa locality. The outcrop contains three channel complexes comprised of 18 channel elements. While analogous slope channel deposits can contain significant reservoir potential, their channelized nature creates uncertain connectivity, which can be problematic for efficient hydrocarbon production. This work seeks to quantify the influence of reservoir architecture on reservoir productivity as a function of well placement and inter-/intra-channel architecture using a high-resolution outcrop-based geocellular model. Reservoir flow simulation is performed to assess the impact of intra-channel architecture on production profiles. Simulated production data is analyzed to elucidate potential clues useful for predicting channel dimensions and connectivity in new and/or producing fields. Reservoir simulations were run for: 1) a single channel element and 2) sector models representing areas of vertically aligned versus laterally offset channel elements. All models were represented at a 2 m x 2 m x 0.25 m grid scale. Three primary facies associations (FA) capture the lithologies present in outcrop: FA1 (axial) – thick-bedded amalgamated sandstone (95% sandstone); FA2 (off-axis) – thick- to thin-bedded semi-amalgamated sandstone with few fine-grained interbeds (81% sandstone); FA3 (marginal) – thin-bedded fine- to very fine-grained sandstone with interbedded siltstone and mudstone (39% sandstone). Three scenarios were created to quantify the influence of reservoir architecture on productivity by varying the proportion and distribution of facies within each channel element. Scenarios capture a range of possible architectural frameworks from highly connected FA1-dominant to more compartmentalized FA2- and FA3-dominant conditions. Hydrocarbon production was simulated from a single extraction well at the axis of the channel element(s) and two water flood injectors 35 meters from the channel margins. Inter- and intra-channel connectivity were evaluated based on the volume and location of oil left in place following water breakthrough. The influence of well placement on productivity was quantified by rerunning each of the realizations with injectors rotated to the center of the channel(s) up- and down-gradient of the production well. Panel_14788 Panel_14788 8:30 AM 5:00 PM

It is now well known that pore development in organic-rich mudrocks is associated with organic matter (OM) thermal maturation. Organic-rich mudrocks usually contain mixed types of kerogen. Therefore, routinely-used vitrinite reflectance measurements cannot define exact OM transformation stages. Understanding the evolution of OM-hosted pores and mineral pores to well-defined oil and gas generation stage is essential to characterize mudrock reservoirs. Immature Barnett (quartz and clay mineral-rich), Woodford chert and mudstone (quartz and clay mineral-rich), and low-maturity Boquillas (carbonate-rich) core and outcrop samples were heated anhydrously in gold tubes to study the evolution of OM and OM pores during maturation. Geochemical characterization such as oil and gas yields, Rock-Eval, and Leco TOC analyses were used to characterize kerogen type and OM transformation stages. Samples were also prepared using Ar-ion milling to investigate pore development with field-emission scanning electron microscopy (FE-SEM). The OM in these immature and low-maturity mudrocks can be dominantly kerogen (Barnett) or bitumen (Boquillas) or a mixture. The difference between kerogen (insoluble in-situ OM) and bitumen (soluble migrated OM) significantly affects OM pore shape and size with increasing thermal maturation because kerogen, which initially thermally cracks to bitumen, contains more inert (dead) carbon than bitumen. Mudrocks with the same total organic carbon (TOC) content but different proportions of kerogen and bitumen show different styles of OM pore evolution. In the Woodford chert and Bouquillas Fm, micron-sized interface pores and OM pores are dominant during bitumen and oil generation, while during gas generation, nm-sized equant OM-hosted pores are dominant. The nanometer-sized equant OM-hosted pores observed during wet gas and dry gas window are interpreted to be related to gas generation. In the Barnett and Woodford mudstone, as maturation begins, OM first shrinks, forming artificial shrinkage pores. Later, the volume of OM significantly decreases with the formation of OM pores. These pores continue to develop into the gas generation stage. It is now well known that pore development in organic-rich mudrocks is associated with organic matter (OM) thermal maturation. Organic-rich mudrocks usually contain mixed types of kerogen. Therefore, routinely-used vitrinite reflectance measurements cannot define exact OM transformation stages. Understanding the evolution of OM-hosted pores and mineral pores to well-defined oil and gas generation stage is essential to characterize mudrock reservoirs. Immature Barnett (quartz and clay mineral-rich), Woodford chert and mudstone (quartz and clay mineral-rich), and low-maturity Boquillas (carbonate-rich) core and outcrop samples were heated anhydrously in gold tubes to study the evolution of OM and OM pores during maturation. Geochemical characterization such as oil and gas yields, Rock-Eval, and Leco TOC analyses were used to characterize kerogen type and OM transformation stages. Samples were also prepared using Ar-ion milling to investigate pore development with field-emission scanning electron microscopy (FE-SEM). The OM in these immature and low-maturity mudrocks can be dominantly kerogen (Barnett) or bitumen (Boquillas) or a mixture. The difference between kerogen (insoluble in-situ OM) and bitumen (soluble migrated OM) significantly affects OM pore shape and size with increasing thermal maturation because kerogen, which initially thermally cracks to bitumen, contains more inert (dead) carbon than bitumen. Mudrocks with the same total organic carbon (TOC) content but different proportions of kerogen and bitumen show different styles of OM pore evolution. In the Woodford chert and Bouquillas Fm, micron-sized interface pores and OM pores are dominant during bitumen and oil generation, while during gas generation, nm-sized equant OM-hosted pores are dominant. The nanometer-sized equant OM-hosted pores observed during wet gas and dry gas window are interpreted to be related to gas generation. In the Barnett and Woodford mudstone, as maturation begins, OM first shrinks, forming artificial shrinkage pores. Later, the volume of OM significantly decreases with the formation of OM pores. These pores continue to develop into the gas generation stage. Panel_14794 Panel_14794 8:30 AM 5:00 PM

The largest deepwater oil discoveries of the past 10 years were found in carbonate-filled, sag basins of the Equatorial and South Atlantic Ocean. We explain the asymmetrical distribution and thickness variations in the areas of pre-salt carbonate sag basins in Brazil and West Africa by, first, isostatically correcting the top of oceanic crust in the area of the Santos to Espirto basins of Brazil and their conjugates in the Namibe and Kwanza basins of Namibia and Angola to improve the location of the continent-ocean boundaries in these areas; and, second, using bathymetric, gravity, magnetic and 1,700 km of regional seismic transects to define the footwall versus hanging wall of the asymmetrical rift margins for both conjugates. For the Santos-Namibe conjugate, we propose Santos to be the hanging wall of an asymmetrical rift system with a 200-km-wide rifted margin and overlying sag basin with carbonate reservoir facies and sloping bathymetric profile; and the Namibe to be the footwall with a 125-km-wide rift and sag basin and steeper bathymetric profile. For the Campos-Kwanza conjugate 400 km to the north, we propose Campos to be the footwall with a 150-km-wide rift zone and overlying sag basin and sloping bathymetric profile. Well data shows that thicker the carbonate sag (135- 325 m) and its overlying salt basin (up to 2 km) are associated with the hanging wall blocks of Kwanza and Santos and the thinner carbonate sag (15-75 m) and its overlying salt basins (up to 1.5 km) are associated with the footwall blocks in accord with predictions based on recent analog modeling. Reservoirs within the sag phase of these conjugate margins include high porosity and permeability lacustrine carbonates deposited in high-energy ooid and oncoid beds along with highly porous travertine hot-spring deposits that include very porous tufa mounds sealed by 1 km or more of overlying salt. These reservoirs are sourced by brackish-lacustrine shales deposited during the sag phase, interbedded with the carbonates. Based on these correlations we predict more potential for larger discoveries in thicker sags/carbonate reservoirs associated with hanging walls underlying Santos and Kwanza. The largest deepwater oil discoveries of the past 10 years were found in carbonate-filled, sag basins of the Equatorial and South Atlantic Ocean. We explain the asymmetrical distribution and thickness variations in the areas of pre-salt carbonate sag basins in Brazil and West Africa by, first, isostatically correcting the top of oceanic crust in the area of the Santos to Espirto basins of Brazil and their conjugates in the Namibe and Kwanza basins of Namibia and Angola to improve the location of the continent-ocean boundaries in these areas; and, second, using bathymetric, gravity, magnetic and 1,700 km of regional seismic transects to define the footwall versus hanging wall of the asymmetrical rift margins for both conjugates. For the Santos-Namibe conjugate, we propose Santos to be the hanging wall of an asymmetrical rift system with a 200-km-wide rifted margin and overlying sag basin with carbonate reservoir facies and sloping bathymetric profile; and the Namibe to be the footwall with a 125-km-wide rift and sag basin and steeper bathymetric profile. For the Campos-Kwanza conjugate 400 km to the north, we propose Campos to be the footwall with a 150-km-wide rift zone and overlying sag basin and sloping bathymetric profile. Well data shows that thicker the carbonate sag (135- 325 m) and its overlying salt basin (up to 2 km) are associated with the hanging wall blocks of Kwanza and Santos and the thinner carbonate sag (15-75 m) and its overlying salt basins (up to 1.5 km) are associated with the footwall blocks in accord with predictions based on recent analog modeling. Reservoirs within the sag phase of these conjugate margins include high porosity and permeability lacustrine carbonates deposited in high-energy ooid and oncoid beds along with highly porous travertine hot-spring deposits that include very porous tufa mounds sealed by 1 km or more of overlying salt. These reservoirs are sourced by brackish-lacustrine shales deposited during the sag phase, interbedded with the carbonates. Based on these correlations we predict more potential for larger discoveries in thicker sags/carbonate reservoirs associated with hanging walls underlying Santos and Kwanza. Panel_14790 Panel_14790 8:30 AM 5:00 PM

Froude transcritical and supercritical or upper flow regime (UFR) sedimentary structures are commonly over looked in fluvial strata, as their presence in the existing fluvial facies models is minor. In many cases they are misinterpreted as cross stratification built by dune migration. In some cases, they are even considered as hummocky (HCS) or swaley cross strata (SCS) built by storm waves. Especially the latter can be a source of misunderstanding and incorrect environmental interpretations. UFR sedimentary structured consist of planar laminations, scour and fill, low angle convex-up laminations, and sigmoidal or humpback cross-laminations. This study aims to provide both quantitative and visual descriptions of the UFR sedimentary structure types, and their internal structural and dimensional variability in fluvial strata, provide recognition criteria and criteria for differentiating these UFR structures from dune cross strata, and from HCS and SCS. The study utilizes field data from the Eocene Wasatch and Green River Formations in the Uinta Basin and the Cretaceous Williams Fork Fm. in the Piceance Basin, and compares to literature descriptions and experimental results. Data were collected by measuring stratigraphic sections, documenting lateral extent of the sedimentary structures, sketching, and taking photographs. These sections were then entered into Microsoft Excel and further quantitatively analyzed. Results indicate that UFR sedimentary structures are common in fluvial strata of flashy or seasonal river systems, where deposition dominantly occurs from high-intensity floods. The UFR structures commonly occur in thick packages indicating high deposition rates. The study highlights that high deposition rates are required to preserve large thicknesses of UFR deposits that otherwise have a very low preservation potential. Other indicators of high deposition rates include aggradational nature of the bedforms and gradational or internally graded nature of the planar laminations. The results help to characterize the deposition that occurs from highly seasonal river systems, such as in monsoonal and subtropical climates. Froude transcritical and supercritical or upper flow regime (UFR) sedimentary structures are commonly over looked in fluvial strata, as their presence in the existing fluvial facies models is minor. In many cases they are misinterpreted as cross stratification built by dune migration. In some cases, they are even considered as hummocky (HCS) or swaley cross strata (SCS) built by storm waves. Especially the latter can be a source of misunderstanding and incorrect environmental interpretations. UFR sedimentary structured consist of planar laminations, scour and fill, low angle convex-up laminations, and sigmoidal or humpback cross-laminations. This study aims to provide both quantitative and visual descriptions of the UFR sedimentary structure types, and their internal structural and dimensional variability in fluvial strata, provide recognition criteria and criteria for differentiating these UFR structures from dune cross strata, and from HCS and SCS. The study utilizes field data from the Eocene Wasatch and Green River Formations in the Uinta Basin and the Cretaceous Williams Fork Fm. in the Piceance Basin, and compares to literature descriptions and experimental results. Data were collected by measuring stratigraphic sections, documenting lateral extent of the sedimentary structures, sketching, and taking photographs. These sections were then entered into Microsoft Excel and further quantitatively analyzed. Results indicate that UFR sedimentary structures are common in fluvial strata of flashy or seasonal river systems, where deposition dominantly occurs from high-intensity floods. The UFR structures commonly occur in thick packages indicating high deposition rates. The study highlights that high deposition rates are required to preserve large thicknesses of UFR deposits that otherwise have a very low preservation potential. Other indicators of high deposition rates include aggradational nature of the bedforms and gradational or internally graded nature of the planar laminations. The results help to characterize the deposition that occurs from highly seasonal river systems, such as in monsoonal and subtropical climates. Panel_14787 Panel_14787 8:30 AM 5:00 PM

Submarine canyons and slope valleys represent significant pathways for coarse-grained sediment transfer across seascapes, providing a critical link between continents and the deep-sea. Abundant material is bypassed basinward, or deposited locally, recording protracted sediment transfer processes. From seafloor and seismic-reflection data, the edges of these conduits are evidently shaped by varied processes including erosion, mass-wasting and in some instances, onlap of fine-grained terrace or inner levee deposits. The stratigraphic expression of canyon or valley walls is presumably characterized by composite surfaces shaped by these innumerable and varied gravity flow events. To consider this hypothesis, the transition from conduit axis to edge is examined in outcropping deep-sea deposits of the Nanaimo Gp. on Hornby Island, BC. The present-day morphology of Hornby Island is shaped by resistant submarine conduit conglomerate and sandstone at its core, and corresponding recessive fine-grained margin deposits along its intertidal shorelines. The paleo-conduits, recorded by >500 m of gross strata, trend SW-W. An outcrop on the south side of the island at Downes Point features the transition from conduit axis to margin. The transition occurs over 500 m laterally and through 110 m of stratigraphy. It reveals a series of features consistent with protracted sediment transfer processes: (1) steep edges of conglomeratic channel fill punctuated by steps that record shifts of the formative channel over time; (2) strata between successive conglomerates dominated by lenticular thin- to thick-bedded sandstone and mudstone associated with scours and barforms; (3) locally abundant remobilized sedimentary blocks up to 30 m in diameter in a zone 125 m wide and 40 m thick present beneath and between channel fill and the conduit edge. The blocks originated from retrogressive slumping of a tabular sandstone package into the conduit, perhaps an inner levee. A series of near vertical failure planes are apparent, with the most axial evidently an important source of slump blocks. Towards the conduit margin, these failure planes are associated with progressively less deformed and rotated sedimentary units. This high-resolution perspective sheds critical insight into the meaning of the stratigraphic record, validating a complex history of sediment transfer, including erosion, mass failure, sediment bypass and deposition, at the composite margin of large-scale submarine conduits. Submarine canyons and slope valleys represent significant pathways for coarse-grained sediment transfer across seascapes, providing a critical link between continents and the deep-sea. Abundant material is bypassed basinward, or deposited locally, recording protracted sediment transfer processes. From seafloor and seismic-reflection data, the edges of these conduits are evidently shaped by varied processes including erosion, mass-wasting and in some instances, onlap of fine-grained terrace or inner levee deposits. The stratigraphic expression of canyon or valley walls is presumably characterized by composite surfaces shaped by these innumerable and varied gravity flow events. To consider this hypothesis, the transition from conduit axis to edge is examined in outcropping deep-sea deposits of the Nanaimo Gp. on Hornby Island, BC. The present-day morphology of Hornby Island is shaped by resistant submarine conduit conglomerate and sandstone at its core, and corresponding recessive fine-grained margin deposits along its intertidal shorelines. The paleo-conduits, recorded by >500 m of gross strata, trend SW-W. An outcrop on the south side of the island at Downes Point features the transition from conduit axis to margin. The transition occurs over 500 m laterally and through 110 m of stratigraphy. It reveals a series of features consistent with protracted sediment transfer processes: (1) steep edges of conglomeratic channel fill punctuated by steps that record shifts of the formative channel over time; (2) strata between successive conglomerates dominated by lenticular thin- to thick-bedded sandstone and mudstone associated with scours and barforms; (3) locally abundant remobilized sedimentary blocks up to 30 m in diameter in a zone 125 m wide and 40 m thick present beneath and between channel fill and the conduit edge. The blocks originated from retrogressive slumping of a tabular sandstone package into the conduit, perhaps an inner levee. A series of near vertical failure planes are apparent, with the most axial evidently an important source of slump blocks. Towards the conduit margin, these failure planes are associated with progressively less deformed and rotated sedimentary units. This high-resolution perspective sheds critical insight into the meaning of the stratigraphic record, validating a complex history of sediment transfer, including erosion, mass failure, sediment bypass and deposition, at the composite margin of large-scale submarine conduits. Panel_14796 Panel_14796 8:30 AM 5:00 PM

The sedimentologic aspects of carbonate facies are well documented; however the distribution and effects of bioturbation of carbonate strata are less well constrained. To address this issue, this study evaluates traces and ichnofabrics in Pleistocene, Holocene, and modern carbonate shoreface successions on Crooked-Acklins Platform, southern Bahamas. The goal of this project is to produce a conceptual ichnofacies model that relates the nature, control, and impact of bioturbation to specific carbonate sedimentary textures and facies. Such ichnological and sedimentological understanding can be used to reconstruct facies distributions within heterogeneous ancient carbonate systems. As part of a larger study, this project focuses on Pleistocene strata of Crooked Island and Long Cay, Bahamas. Pleistocene strata include coralline boundstone and rudstone deposits <0.5 km wide along strike, interpreted as patch reefs, and cross-stratified peloid-skeletal-ooid grainstone, interpreted as shoreface and backshore deposits. Pleistocene strata form elongate, margin-parallel topographic ridges characterized by an upward decrease in grain size and ichnofabric index (ii), and an increase in rhizolith content. Trace fossils within the topographic highs of ridge successions include vertical burrows (e.g., Conichnus, Skolithos) and boxwork burrows (e.g., Ophiomorpha) that have lined or reinforced walls, indicating a higher energy, shifting seafloor. These areas exhibit ii 2–3, and generally have less diverse trace fossil assemblages than the low-lying areas. Conversely, paleotopographic lows between ridges exhibit traces that are predominantly vertical to oblique to bedding planes (e.g., Cylindrichnus, Rosselia, escape burrows), and generally have ii 4–5. These highly bioturbated areas represent stabilized, subtidal sediments deposited in an upper shoreface environment. Petrographic analyses reveal that these shoreface facies of Crooked Island are dominantly fine-sand peloid-ooid grainstone with varying amounts of skeletal debris. In the Pleistocene samples, primary porosity is preserved with clear equant calcite cement and can exceed 25%. These results indicate how trace fossil associations, ichnofabric indices, and porosity and permeability trends are related to depositional energy, facies, and position within geomorphic bodies. Insights from this study provide a conceptual framework for stratigraphic architecture and heterogeneity in subsurface shoreface analogs. The sedimentologic aspects of carbonate facies are well documented; however the distribution and effects of bioturbation of carbonate strata are less well constrained. To address this issue, this study evaluates traces and ichnofabrics in Pleistocene, Holocene, and modern carbonate shoreface successions on Crooked-Acklins Platform, southern Bahamas. The goal of this project is to produce a conceptual ichnofacies model that relates the nature, control, and impact of bioturbation to specific carbonate sedimentary textures and facies. Such ichnological and sedimentological understanding can be used to reconstruct facies distributions within heterogeneous ancient carbonate systems. As part of a larger study, this project focuses on Pleistocene strata of Crooked Island and Long Cay, Bahamas. Pleistocene strata include coralline boundstone and rudstone deposits <0.5 km wide along strike, interpreted as patch reefs, and cross-stratified peloid-skeletal-ooid grainstone, interpreted as shoreface and backshore deposits. Pleistocene strata form elongate, margin-parallel topographic ridges characterized by an upward decrease in grain size and ichnofabric index (ii), and an increase in rhizolith content. Trace fossils within the topographic highs of ridge successions include vertical burrows (e.g., Conichnus, Skolithos) and boxwork burrows (e.g., Ophiomorpha) that have lined or reinforced walls, indicating a higher energy, shifting seafloor. These areas exhibit ii 2–3, and generally have less diverse trace fossil assemblages than the low-lying areas. Conversely, paleotopographic lows between ridges exhibit traces that are predominantly vertical to oblique to bedding planes (e.g., Cylindrichnus, Rosselia, escape burrows), and generally have ii 4–5. These highly bioturbated areas represent stabilized, subtidal sediments deposited in an upper shoreface environment. Petrographic analyses reveal that these shoreface facies of Crooked Island are dominantly fine-sand peloid-ooid grainstone with varying amounts of skeletal debris. In the Pleistocene samples, primary porosity is preserved with clear equant calcite cement and can exceed 25%. These results indicate how trace fossil associations, ichnofabric indices, and porosity and permeability trends are related to depositional energy, facies, and position within geomorphic bodies. Insights from this study provide a conceptual framework for stratigraphic architecture and heterogeneity in subsurface shoreface analogs. Panel_14785 Panel_14785 8:30 AM 5:00 PM

Deltaic deposits contain vast petroleum reservoirs and source rocks, but facies models have not advanced at the same pace as the growing body of work demonstrating multiple controls on facies distribution and sequence development in modern deltas. Refinement of these models requires more studies documenting lateral sedimentological and ichnological facies changes in well-exposed ancient deltas. Presented here are depositional strike and dip transects through world-class exposures of deltaic strata in the Ferron “Notom” delta on the western and southern flanks of the Henry Mountains Syncline, southeastern Utah. One transect covers the complete 16 km-long strike profiles of two 10 m-thick delta front sandstone bodies with discrete mouth bar and channel facies marking the locations of riverine input. Most delta front facies contain a stressed suite of low abundance, low diversity, diminutive traces, but ichnosuites downdrift of river mouths are comparatively unstressed with a high abundance of deep, vertical, or U-shaped suspension feeding burrows. This distribution of ichnosuites contrasts sharply with existing models and likely reflects abundant nutrient supply in river-born waters carried southward by coastal currents, or alternatively, reduction of physio-chemical stresses during seasonal reversal of coastal currents. The 8 km-long dip profile covers several sandstone bodies below and above a major subaerial unconformity (SU). Up-dip, the SU is marked by heavily rooted coastal plain facies and incised channels atop mouth bar and delta front facies. Down-dip, the SU descends relative to the coastal plain/channel facies, becoming a cryptic surface encased within coarsening-upward delta front cycles. The SU separates a lower package of offlapping mouth bar/delta front strata with multiple discontinuities from an upper, nearly complete progradational succession capped by channel and coastal plain facies. This change in stratal stacking marks a change from a low-accommodation, falling stage delta complex to a comparatively higher accommodation progradational-aggradational delta. New insights to the controls on deltaic facies variability are gained through these unique windows into deltaic architecture via the superb exposure. Deltaic deposits contain vast petroleum reservoirs and source rocks, but facies models have not advanced at the same pace as the growing body of work demonstrating multiple controls on facies distribution and sequence development in modern deltas. Refinement of these models requires more studies documenting lateral sedimentological and ichnological facies changes in well-exposed ancient deltas. Presented here are depositional strike and dip transects through world-class exposures of deltaic strata in the Ferron “Notom” delta on the western and southern flanks of the Henry Mountains Syncline, southeastern Utah. One transect covers the complete 16 km-long strike profiles of two 10 m-thick delta front sandstone bodies with discrete mouth bar and channel facies marking the locations of riverine input. Most delta front facies contain a stressed suite of low abundance, low diversity, diminutive traces, but ichnosuites downdrift of river mouths are comparatively unstressed with a high abundance of deep, vertical, or U-shaped suspension feeding burrows. This distribution of ichnosuites contrasts sharply with existing models and likely reflects abundant nutrient supply in river-born waters carried southward by coastal currents, or alternatively, reduction of physio-chemical stresses during seasonal reversal of coastal currents. The 8 km-long dip profile covers several sandstone bodies below and above a major subaerial unconformity (SU). Up-dip, the SU is marked by heavily rooted coastal plain facies and incised channels atop mouth bar and delta front facies. Down-dip, the SU descends relative to the coastal plain/channel facies, becoming a cryptic surface encased within coarsening-upward delta front cycles. The SU separates a lower package of offlapping mouth bar/delta front strata with multiple discontinuities from an upper, nearly complete progradational succession capped by channel and coastal plain facies. This change in stratal stacking marks a change from a low-accommodation, falling stage delta complex to a comparatively higher accommodation progradational-aggradational delta. New insights to the controls on deltaic facies variability are gained through these unique windows into deltaic architecture via the superb exposure. Panel_14795 Panel_14795 8:30 AM 5:00 PM

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Panel_14423 Panel_14423 8:30 AM 5:00 PM

The development of unconventional oil and gas (UOG) resources have become an important facet of the US and global energy portfolio. Currently, UOG resources account for more than one-third of the natural gas production in the US. Despite the success in generating shale gas, there are still questions about maximizing the recovery of hydrocarbons and determining the origin of organic matter in black shales. The Marcellus Formation is one of the largest shale plays in the US. Even though ongoing hydrocarbon exploitation is taking place in this area, there is still significant unknown factors about the original depositional conditions of the Marcellus and other organic-rich black shales. Geochemical techniques that employ major and trace elements, along with carbon and nitrogen stable isotopes are often used to characterize depositional and diagenetic conditions. Lithophilic elements serve as robust proxies for understanding sedimentation and provenance, while the behavior of siderophiles and chalcophiles are suitable in reconstructing redox conditions, and lastly, stable isotopes are employed to describe biogeochemical cycles as well as primary productivity prior to deposition. Here we will present multiple lines of geochemical data used to reconstruct the paleoenvironment that led to formation of the Marcellus shale. Implementing a multiproxy approach that involves major, trace, and rare earth elements, through x-ray fluorescence and inductively coupled plasma mass spectroscopy, along with carbon and nitrogen stable isotope analysis through elemental analyzer isotope mass spectroscopy. Using this multiproxy approach we will characterize the paleoenvironment from the Marcellus locality in Seneca Falls, NY. From our preliminary results, variations in geochemical signatures along with high total organic carbon content suggest that persistent anoxic conditions as a major factor in developing UOG areas. The development of unconventional oil and gas (UOG) resources have become an important facet of the US and global energy portfolio. Currently, UOG resources account for more than one-third of the natural gas production in the US. Despite the success in generating shale gas, there are still questions about maximizing the recovery of hydrocarbons and determining the origin of organic matter in black shales. The Marcellus Formation is one of the largest shale plays in the US. Even though ongoing hydrocarbon exploitation is taking place in this area, there is still significant unknown factors about the original depositional conditions of the Marcellus and other organic-rich black shales. Geochemical techniques that employ major and trace elements, along with carbon and nitrogen stable isotopes are often used to characterize depositional and diagenetic conditions. Lithophilic elements serve as robust proxies for understanding sedimentation and provenance, while the behavior of siderophiles and chalcophiles are suitable in reconstructing redox conditions, and lastly, stable isotopes are employed to describe biogeochemical cycles as well as primary productivity prior to deposition. Here we will present multiple lines of geochemical data used to reconstruct the paleoenvironment that led to formation of the Marcellus shale. Implementing a multiproxy approach that involves major, trace, and rare earth elements, through x-ray fluorescence and inductively coupled plasma mass spectroscopy, along with carbon and nitrogen stable isotope analysis through elemental analyzer isotope mass spectroscopy. Using this multiproxy approach we will characterize the paleoenvironment from the Marcellus locality in Seneca Falls, NY. From our preliminary results, variations in geochemical signatures along with high total organic carbon content suggest that persistent anoxic conditions as a major factor in developing UOG areas. Panel_14885 Panel_14885 8:30 AM 5:00 PM

The analysis of anisotropy especially in unconventional reservoirs is becoming increasingly important in modelling reservoir response particularly to hydraulic fracturing. As the electrical response in shales and mudstones depend on microstructure and intrinsic anisotropy, an understanding of resistivity anisotropy may provide insights into their stress response to loading. Although multi-component induction logging data for some shales show that electrical resistivities perpendicular to bedding are greater than electrical resistivities parallel to bedding, an understanding of 3D electrical response of shales and mudstones is lacking. Moreover, logging tools that measure both horizontal and vertical resistivities are not commonly used. In this study, a method for determining the anisotropy of electrical resistivity of the Devonian Horn River Group of the Horn River Basin, British Columbia, is detailed and factors controlling the electrical fabric are determined by relating results to elements of petrofabric observed in thin section. The formations of the Horn River Group are an ideal sample set with three distinct lithofacies identified. Siliceous clay rich mudstone intervals are observed in the Muskwa and Otter Park, argillaceous laminated shales dominate the Otter Park and clay rich calcareous mudstones make up the Evie formation. Traditional laboratory methods of measuring anisotropy require that core plugs be taken in a number of desirable directions. A 3 dimensional look at electrical resistivity is difficult with these methods since multiple plugs have to be taken for one sampling interval/depth and the available sample size may not allow for this. Moreover, the fissile nature of shales makes it challenging to retrieve multiple usable plugs from a sampling interval. In the method used in this study, for each interval sampled, 18 different directional electrical resistance measurements are made on a single eight sided prism shaped sample saturated in a potassium chloride electrolyte solution. To convert directional resistances to resistivities, integration in the direction of current flow is used. From the directional resistivities, the ellipsoid describing the electrical resistivity tensor is determined. Results show that all three formations in the Horn River Group are transversely anisotropic with an axis of symmetry perpendicular to the bedding plane. All formations also exhibit varying, but strong electrical anisotropy. Mineralogy, especially the distribution and alignment of clays and carbonate grains as well as the presence of fine laminations appear to be the primary control on the anisotropy of electrical resistivity. The presence of pyrite streaks and lenses in the Otter Park and Muskwa may also contribute to their anisotropy of electrical resistivity. The analysis of anisotropy especially in unconventional reservoirs is becoming increasingly important in modelling reservoir response particularly to hydraulic fracturing. As the electrical response in shales and mudstones depend on microstructure and intrinsic anisotropy, an understanding of resistivity anisotropy may provide insights into their stress response to loading. Although multi-component induction logging data for some shales show that electrical resistivities perpendicular to bedding are greater than electrical resistivities parallel to bedding, an understanding of 3D electrical response of shales and mudstones is lacking. Moreover, logging tools that measure both horizontal and vertical resistivities are not commonly used. In this study, a method for determining the anisotropy of electrical resistivity of the Devonian Horn River Group of the Horn River Basin, British Columbia, is detailed and factors controlling the electrical fabric are determined by relating results to elements of petrofabric observed in thin section. The formations of the Horn River Group are an ideal sample set with three distinct lithofacies identified. Siliceous clay rich mudstone intervals are observed in the Muskwa and Otter Park, argillaceous laminated shales dominate the Otter Park and clay rich calcareous mudstones make up the Evie formation. Traditional laboratory methods of measuring anisotropy require that core plugs be taken in a number of desirable directions. A 3 dimensional look at electrical resistivity is difficult with these methods since multiple plugs have to be taken for one sampling interval/depth and the available sample size may not allow for this. Moreover, the fissile nature of shales makes it challenging to retrieve multiple usable plugs from a sampling interval. In the method used in this study, for each interval sampled, 18 different directional electrical resistance measurements are made on a single eight sided prism shaped sample saturated in a potassium chloride electrolyte solution. To convert directional resistances to resistivities, integration in the direction of current flow is used. From the directional resistivities, the ellipsoid describing the electrical resistivity tensor is determined. Results show that all three formations in the Horn River Group are transversely anisotropic with an axis of symmetry perpendicular to the bedding plane. All formations also exhibit varying, but strong electrical anisotropy. Mineralogy, especially the distribution and alignment of clays and carbonate grains as well as the presence of fine laminations appear to be the primary control on the anisotropy of electrical resistivity. The presence of pyrite streaks and lenses in the Otter Park and Muskwa may also contribute to their anisotropy of electrical resistivity. Panel_14890 Panel_14890 8:30 AM 5:00 PM

The upper Cretaceous La Luna Formation is of crucial importance in the petroleum geology of northern South-America, especially in Venezuela and Colombia. The largest in situ oil accumulation in the world (1.5 trillion barrels) is located in eastern Venezuela associated with the La Luna source rock. The La Luna is now being considered an unconventional shale prospect (PDVSA-2012). This preliminary study encompasses stratigraphic and geochemical characterization of La Luna Formation from seven outcrops and one 345ft. core along the North Andean flank and the northwest of Lago de Maracaibo Basin. TOC content from the core varies from 0.22 to 9.13 wt% (average 4.01 wt. %). Rock-Eval pyrolysis results highlighted type I and type II kerogen, a “Good-to-Excellent” oil potential generation and a maturity indicator suggesting a greater likelihood of oil than gas. The Delta Log R method (Passey, 1990) of TOC estimation, showed a good agreement with the Rock-Eval results. Eight facies were defined in the La Luna core. From bottom to top: dark gray, laminated mudstone; calcareous shales; laminated mudstone with limestone concretions; laminated mudstone interbedded with black chert filled with calcite veins; brown mudstone with strong petroleum odor; volcanic ash beds; calcareous, laminated black mudstone interbedded with fossiliferous wackstone. Planktonic foraminifera are present in the upper part of the interval. These results serve as a baseline for current study of the La Luna Formation in Venezuela. The upper Cretaceous La Luna Formation is of crucial importance in the petroleum geology of northern South-America, especially in Venezuela and Colombia. The largest in situ oil accumulation in the world (1.5 trillion barrels) is located in eastern Venezuela associated with the La Luna source rock. The La Luna is now being considered an unconventional shale prospect (PDVSA-2012). This preliminary study encompasses stratigraphic and geochemical characterization of La Luna Formation from seven outcrops and one 345ft. core along the North Andean flank and the northwest of Lago de Maracaibo Basin. TOC content from the core varies from 0.22 to 9.13 wt% (average 4.01 wt. %). Rock-Eval pyrolysis results highlighted type I and type II kerogen, a “Good-to-Excellent” oil potential generation and a maturity indicator suggesting a greater likelihood of oil than gas. The Delta Log R method (Passey, 1990) of TOC estimation, showed a good agreement with the Rock-Eval results. Eight facies were defined in the La Luna core. From bottom to top: dark gray, laminated mudstone; calcareous shales; laminated mudstone with limestone concretions; laminated mudstone interbedded with black chert filled with calcite veins; brown mudstone with strong petroleum odor; volcanic ash beds; calcareous, laminated black mudstone interbedded with fossiliferous wackstone. Planktonic foraminifera are present in the upper part of the interval. These results serve as a baseline for current study of the La Luna Formation in Venezuela. Panel_14892 Panel_14892 8:30 AM 5:00 PM

Samples from the Middle and Upper Devonian Horn River shale, a major gas shale play in northeastern British Columbia, were assessed with a variety of techniques to understand controls on petrophysical properties, including porosity, permeability and pore system dimensions. Samples were examined by ICP-MS, Rock-Eval pyrolysis, helium porosimetry, pulse decay permeability analysis, SEM imaging of ion milled samples, nitrogen adsorption measurements and mercury injection analysis; and the results were compared to rock composition.The Evie, Otter Park and Muskwa Formations exhibit a range of organic and inorganic compositions, suggesting that reservoir quality should be stratigraphically constrained. The Evie Formation is carbonate-rich, while the Otter Park and Muskwa Formations are clay-rich and quartz-rich, respectively. The Evie has moderate organic matter concentration. The Otter Park is characterized by the lowest organic matter enrichment, while the Muskwa has the highest TOC content. Porosity ranges from 2.4 to 10.8% and is slightly elevated in the Evie Formation. A positive correlation is observed between porosity, organic matter abundance and quartz content, probably indicating that organic matter content is a primary factor controlling porosity development. A similar correlation between TOC and quartz indicates the latter is mainly biogenic in origin. Negative correlations are observed between porosity and the carbonate and clay content. SEM images suggest that in Horn river mudstones, several kinds of sites are provided for porosity development, including organic matter, pyrite framboids, clay plates, quartz rims and fractures. Results from nitrogen adsorption and mercury injection analysis suggest that pore size distribution includes micropores, mesopores and macropores, ranging from 1 nm to 1000 nm. Pores more than 10 nm dominate in terms of volume. Permeability ranges from 3.4 to 33 nanodarcy. Sea level fluctuation has direct impacts on geochemical composition and indirect influence on the petrophysical propreties. Evie, Otter Park and Muskwa formations are assigned to HST, TST, and LST, respectively. Shale successions deposited during rising sea level stage (Evie and Muskwa formation) have higher porosity than intervals deposited during falling sea level stage (Otter Park formation), possibly because rising sea level rising is more favorable for organic matter accumulation. Samples from the Middle and Upper Devonian Horn River shale, a major gas shale play in northeastern British Columbia, were assessed with a variety of techniques to understand controls on petrophysical properties, including porosity, permeability and pore system dimensions. Samples were examined by ICP-MS, Rock-Eval pyrolysis, helium porosimetry, pulse decay permeability analysis, SEM imaging of ion milled samples, nitrogen adsorption measurements and mercury injection analysis; and the results were compared to rock composition.The Evie, Otter Park and Muskwa Formations exhibit a range of organic and inorganic compositions, suggesting that reservoir quality should be stratigraphically constrained. The Evie Formation is carbonate-rich, while the Otter Park and Muskwa Formations are clay-rich and quartz-rich, respectively. The Evie has moderate organic matter concentration. The Otter Park is characterized by the lowest organic matter enrichment, while the Muskwa has the highest TOC content. Porosity ranges from 2.4 to 10.8% and is slightly elevated in the Evie Formation. A positive correlation is observed between porosity, organic matter abundance and quartz content, probably indicating that organic matter content is a primary factor controlling porosity development. A similar correlation between TOC and quartz indicates the latter is mainly biogenic in origin. Negative correlations are observed between porosity and the carbonate and clay content. SEM images suggest that in Horn river mudstones, several kinds of sites are provided for porosity development, including organic matter, pyrite framboids, clay plates, quartz rims and fractures. Results from nitrogen adsorption and mercury injection analysis suggest that pore size distribution includes micropores, mesopores and macropores, ranging from 1 nm to 1000 nm. Pores more than 10 nm dominate in terms of volume. Permeability ranges from 3.4 to 33 nanodarcy. Sea level fluctuation has direct impacts on geochemical composition and indirect influence on the petrophysical propreties. Evie, Otter Park and Muskwa formations are assigned to HST, TST, and LST, respectively. Shale successions deposited during rising sea level stage (Evie and Muskwa formation) have higher porosity than intervals deposited during falling sea level stage (Otter Park formation), possibly because rising sea level rising is more favorable for organic matter accumulation. Panel_14891 Panel_14891 8:30 AM 5:00 PM

Here we document the mineralogical composition and the diagenetic alterations of the Eagle Ford Fm. We focus on mineral formation and evolution during burial through mineralogical and petrographic analysis using XRD, optical and electron microscopy, and stable isotope analysis and highlight controls upon reservoir quality. The Eagle Ford Fm is principally an organic rich marl, which experienced early diagenetic calcite precipitation as a result of organic matter oxidation and sulphate reduction. Calcite cements take the form of replacements of foraminifera tests and micrite coatings on coccolith fragments within the argillaceous matrix. Detrital smectite and illite are the main clay component, however authigenic kaolinite and chlorite are common, especially in the lower Eagle Ford Fmn. Concretions and limestone beds are major features in the lower Eagle Ford Fmn. Concretions are laterally discontinuous in outcrop, some up to 20cm thick and 1m long. The limestone beds are continuous in outcrop and are commonly >30cm thick. Optical microscopy and cathodoluminescence (CL) show calcite precipitation within the concretions is extensive and invasive and occurs early during burial. Abrupt changes to the pore water chemistry are interpreted to be caused by microbial activity and are the cause of the nodular concretions within the organic marls. Initial inorganic oxygen isotope analysis indicates similar sea surface temperature (SST) and depositional environments for the organic marls and nodular concretions, suggesting the concretions and limestones are purely diagenetic. Carbon and oxygen isotope data will be used to constrain this further. We can identify different fabrics and pore types based on mineralogy and organic matter content that can help optimise target definition, well completion and development of the Eagle Ford Fm. The lower Eagle Ford Fm is rich in organic matter (TOC~8%) and clay (both detrital and authigenic). In our study area total porosity is 5-8% and is found predominantly within mature organic matter. In the middle Eagle Ford Fmn carbonate content increases with Total porosity and organic content decreasing slightly (TOC~5%). In the middle Eagle Ford Fm porosity is found mainly between euhedral carbonate grains creating intragranular porosity. Different fabrics and pore types have a significant impact on hydrocarbon storage and permeability. Here we document the mineralogical composition and the diagenetic alterations of the Eagle Ford Fm. We focus on mineral formation and evolution during burial through mineralogical and petrographic analysis using XRD, optical and electron microscopy, and stable isotope analysis and highlight controls upon reservoir quality. The Eagle Ford Fm is principally an organic rich marl, which experienced early diagenetic calcite precipitation as a result of organic matter oxidation and sulphate reduction. Calcite cements take the form of replacements of foraminifera tests and micrite coatings on coccolith fragments within the argillaceous matrix. Detrital smectite and illite are the main clay component, however authigenic kaolinite and chlorite are common, especially in the lower Eagle Ford Fmn. Concretions and limestone beds are major features in the lower Eagle Ford Fmn. Concretions are laterally discontinuous in outcrop, some up to 20cm thick and 1m long. The limestone beds are continuous in outcrop and are commonly >30cm thick. Optical microscopy and cathodoluminescence (CL) show calcite precipitation within the concretions is extensive and invasive and occurs early during burial. Abrupt changes to the pore water chemistry are interpreted to be caused by microbial activity and are the cause of the nodular concretions within the organic marls. Initial inorganic oxygen isotope analysis indicates similar sea surface temperature (SST) and depositional environments for the organic marls and nodular concretions, suggesting the concretions and limestones are purely diagenetic. Carbon and oxygen isotope data will be used to constrain this further. We can identify different fabrics and pore types based on mineralogy and organic matter content that can help optimise target definition, well completion and development of the Eagle Ford Fm. The lower Eagle Ford Fm is rich in organic matter (TOC~8%) and clay (both detrital and authigenic). In our study area total porosity is 5-8% and is found predominantly within mature organic matter. In the middle Eagle Ford Fmn carbonate content increases with Total porosity and organic content decreasing slightly (TOC~5%). In the middle Eagle Ford Fm porosity is found mainly between euhedral carbonate grains creating intragranular porosity. Different fabrics and pore types have a significant impact on hydrocarbon storage and permeability. Panel_14889 Panel_14889 8:30 AM 5:00 PM

The U.S. Energy Information Administration (EIA) is updating the index map for the North American shale plays and maps of the individual shale gas and tight oil plays of the lower 48 states, using publically available geologic data and a commercial well-level database (Drilling Info Inc.). Updates to the North American shale play map include revised play boundaries for the Eagle Ford and plays within the Permian Basin, Williston Basin and Appalachian Basin. Thematic maps on production trends from the Eagle Ford, Permian, and Bakken plays were recently published by EIA in Today in Energy articles. A more complete series of maps for individual plays will be posted to the EIA Maps webpage. Maps for the Marcellus, Utica, and Niobrara are under construction and additional maps are planned for the remaining major shale and tight oil plays for which sufficient well, production, and geologic data are available. For the individual plays, the geologic elements characterized and updated include contoured elevation of the top of formation, isopach, major structures and tectonic features, play boundaries, well locations, and gas-to oil ratios of producing wells. Additional map layers will be added as additional geologic data becomes available. The U.S. Energy Information Administration (EIA) is updating the index map for the North American shale plays and maps of the individual shale gas and tight oil plays of the lower 48 states, using publically available geologic data and a commercial well-level database (Drilling Info Inc.). Updates to the North American shale play map include revised play boundaries for the Eagle Ford and plays within the Permian Basin, Williston Basin and Appalachian Basin. Thematic maps on production trends from the Eagle Ford, Permian, and Bakken plays were recently published by EIA in Today in Energy articles. A more complete series of maps for individual plays will be posted to the EIA Maps webpage. Maps for the Marcellus, Utica, and Niobrara are under construction and additional maps are planned for the remaining major shale and tight oil plays for which sufficient well, production, and geologic data are available. For the individual plays, the geologic elements characterized and updated include contoured elevation of the top of formation, isopach, major structures and tectonic features, play boundaries, well locations, and gas-to oil ratios of producing wells. Additional map layers will be added as additional geologic data becomes available. Panel_14884 Panel_14884 8:30 AM 5:00 PM

The Bakken Formation of the Williston Basin is one of the largest hydrocarbon producers in the U.S. Although several studies have characterized the middle Bakken, the mudrocks of the upper and lower Bakken are understudied. The upper and lower Bakken are both low-oxygen, high-TOC, visually cryptic mudrocks. Like most mudrock successions, however, these rocks are complex mineralogical assemblages that contain a detailed record of the depositional and oceanographic history of the basin. Integration of geochemical analysis, visual core description, and borehole geophysical logs reveals marked changes both within and between the upper and lower Bakken. These observations offer new insights into changes in sediment flux and sea floor oxygenation during Bakken deposition. The goal of this study is to define variations in the rock attributes of the upper and lower Bakken that may relate to reservoir performance, e.g. organic matter distribution, pore characteristics, and brittleness. These attributes correspond to mineralogy and sediment type, which can be defined at high resolution by X-ray fluorescence major element analysis and X-ray diffraction techniques. XRF data provide a superior record of vertical mineralogical facies stacking. XRF trace elements reveal information about oceanographic oxygenation and circulation, which affects the production and preservation of organic matter. Stable isotopes of nitrogen and carbon will help define changes in nutrient supply, which may relate to significant changes in TOC and mineralogy, and serve as a potential basis for local and regional correlation. The study is based on seven cores from North Dakota and Montana. Four of the cores form an east-west cross section in the southwestern part of the basin, which is an approximate proximal to distal succession; the other three cores offer off-axis support. Preliminary study of thin sections from these cores reveals microfractures and some sedimentary structures such as thin laminations, along with abundant pyrite, particularly in the lower Bakken. Bioturbation is rare in the upper and lower Bakken, but common in the coarser-grained middle Bakken, which shows that it represents a much higher-energy, better-oxygenated environment than the mudrocks. Integrated characterization of the Bakken mudrocks provides important clues about both basin history and refined targeting for hydrocarbon exploration. The Bakken Formation of the Williston Basin is one of the largest hydrocarbon producers in the U.S. Although several studies have characterized the middle Bakken, the mudrocks of the upper and lower Bakken are understudied. The upper and lower Bakken are both low-oxygen, high-TOC, visually cryptic mudrocks. Like most mudrock successions, however, these rocks are complex mineralogical assemblages that contain a detailed record of the depositional and oceanographic history of the basin. Integration of geochemical analysis, visual core description, and borehole geophysical logs reveals marked changes both within and between the upper and lower Bakken. These observations offer new insights into changes in sediment flux and sea floor oxygenation during Bakken deposition. The goal of this study is to define variations in the rock attributes of the upper and lower Bakken that may relate to reservoir performance, e.g. organic matter distribution, pore characteristics, and brittleness. These attributes correspond to mineralogy and sediment type, which can be defined at high resolution by X-ray fluorescence major element analysis and X-ray diffraction techniques. XRF data provide a superior record of vertical mineralogical facies stacking. XRF trace elements reveal information about oceanographic oxygenation and circulation, which affects the production and preservation of organic matter. Stable isotopes of nitrogen and carbon will help define changes in nutrient supply, which may relate to significant changes in TOC and mineralogy, and serve as a potential basis for local and regional correlation. The study is based on seven cores from North Dakota and Montana. Four of the cores form an east-west cross section in the southwestern part of the basin, which is an approximate proximal to distal succession; the other three cores offer off-axis support. Preliminary study of thin sections from these cores reveals microfractures and some sedimentary structures such as thin laminations, along with abundant pyrite, particularly in the lower Bakken. Bioturbation is rare in the upper and lower Bakken, but common in the coarser-grained middle Bakken, which shows that it represents a much higher-energy, better-oxygenated environment than the mudrocks. Integrated characterization of the Bakken mudrocks provides important clues about both basin history and refined targeting for hydrocarbon exploration. Panel_14887 Panel_14887 8:30 AM 5:00 PM

Since gas was initially tested from tight sandstones of the Lajas Formation at Aguada Toledo-Sierra Barrosa area in 2004, the Lajas Field has gone through discovery and delineation stages, which included 3D seismic acquisition, 11 new wells drilled, the acquisition of conventional and sidewall cores, complete log suites, and microseismic monitoring of hydraulic fractures. Field development started in 2013 and with more than 100 wells planned, it is becoming one of the most relevant tight gas fields of Argentina, with considerable volumes of gas proved in a productive area of 100 sq km. The reservoir is located in the Cupen Mahuida elongated structural anticline, which is an east-west oriented 4-way dip closure formed by oblique inversion as a fault propagation fold, originated by the Huincul arch activity. The structure strongly controls the gas trap and storage. The Lajas Fm is part of the middle Jurassic Cuyo group. It consists of 900m of sandstones and siltstones deposited in a prograding delta system, from delta front to fluvial facies. Net pay varies from 100 to 300m according to the structural position. Average porosity is 7%, permeability ranges from 0.1 to 0.001 md, and the pressure gradient is normal. In some zones mobile water has been observed. The gas composition is 90% methane and the water saturation is 50%. One of the main challenges for well stimulation is how to identify the water bearing intervals in order to design long fractures contained to avoid the mobile water. The reservoir stimulation has evolved from a few big single point fracs to an average of 10 limited entry fracs. EURs are calculated by conventional and Rate Transient Analysis for this type of reservoir. Relationships between petrophysics and EURs have been established. Production contribution from individual layers and their evolution in time are determined by PLT analysis. The field production has had a dramatic growth during the last 2 years due to an aggressive drilling plan, turning it into the 3rd largest gas field in YPF. The data and experience indicates that, as well as in Greater Green River Basin, these tight gas fields in Neuquen Basin seem to occur in conventional traps. An exception is the lower part of the reservoir which could be associated with a BCGA. There is a huge volume of tight gas resources not yet deeply investigated in this basin which could capitalize on the success and lessons learned from this project. Since gas was initially tested from tight sandstones of the Lajas Formation at Aguada Toledo-Sierra Barrosa area in 2004, the Lajas Field has gone through discovery and delineation stages, which included 3D seismic acquisition, 11 new wells drilled, the acquisition of conventional and sidewall cores, complete log suites, and microseismic monitoring of hydraulic fractures. Field development started in 2013 and with more than 100 wells planned, it is becoming one of the most relevant tight gas fields of Argentina, with considerable volumes of gas proved in a productive area of 100 sq km. The reservoir is located in the Cupen Mahuida elongated structural anticline, which is an east-west oriented 4-way dip closure formed by oblique inversion as a fault propagation fold, originated by the Huincul arch activity. The structure strongly controls the gas trap and storage. The Lajas Fm is part of the middle Jurassic Cuyo group. It consists of 900m of sandstones and siltstones deposited in a prograding delta system, from delta front to fluvial facies. Net pay varies from 100 to 300m according to the structural position. Average porosity is 7%, permeability ranges from 0.1 to 0.001 md, and the pressure gradient is normal. In some zones mobile water has been observed. The gas composition is 90% methane and the water saturation is 50%. One of the main challenges for well stimulation is how to identify the water bearing intervals in order to design long fractures contained to avoid the mobile water. The reservoir stimulation has evolved from a few big single point fracs to an average of 10 limited entry fracs. EURs are calculated by conventional and Rate Transient Analysis for this type of reservoir. Relationships between petrophysics and EURs have been established. Production contribution from individual layers and their evolution in time are determined by PLT analysis. The field production has had a dramatic growth during the last 2 years due to an aggressive drilling plan, turning it into the 3rd largest gas field in YPF. The data and experience indicates that, as well as in Greater Green River Basin, these tight gas fields in Neuquen Basin seem to occur in conventional traps. An exception is the lower part of the reservoir which could be associated with a BCGA. There is a huge volume of tight gas resources not yet deeply investigated in this basin which could capitalize on the success and lessons learned from this project. Panel_14886 Panel_14886 8:30 AM 5:00 PM

The Marcellus Shale is one of the most important gas shale plays in the world as horizontal drilling and hydraulic fracturing have been extensively utilized over the last decade. Sedimentary barite is ubiquitous in the Marcellus Shale and unusually high barium concentrations tend to occur in Marcellus flow back water, which can cause serious scale formation adversely impacting well performance and environmental concerns. This study investigates the characteristics of barite in the Marcellus and provides insights on its regional distribution and origin. Barite is regionally widespread in the Marcellus, focused immediately beneath or within the Cherry Valley Member. Barite-bearing zones range in thickness from centimeters to >3 meters and tend to be thicker in the east thinning westward. Barite occurs commonly as centimeter-scale, oval-shaped nodules, especially in central and western Pennsylvania. Eastward, barite is found as poorly-defined, incipient nodules and disseminated crystal aggregates. Barite in the Marcellus commonly occurs associated with pyrite nodules and carbonate concretions. Compaction-related fabrics indicate that barite formed as a product of early diagenesis. Barite crystals in nodules are typically finely crystalline (5 – 60 µm), becoming more coarsely crystalline (60 µm to >1 mm) eastward towards the Allegheny front. ?34S values determined from barite nodules range from 34.6 to 66.6 ‰. Barite deposits in shale are often considered indicative of low sedimentation rates and may denote a hiatus in sedimentation, which can cause dilute Ba2+ to be significantly enriched by microbial activities leading to barite precipitation. Our regional analysis of over 100 cored wells in the Marcellus documents regional variability in both barite crystal size and sulfur isotopic composition. Coarsely crystalline barite displays low ?34S values when compared to finely crystalline barite which have higher ?34S values. These trends in fabric and sulfur isotope composition are attributed to variable rates of microbial sulfate reduction related to changing sedimentation rates. The high ?34S values associated with the finely crystalline barite result from a lower sedimentation rate and commensurate enhanced microbial sulfate reduction. The Tioga Ash is considered as an important source of Ba2+ in the basin and those areas with thicker ash accumulation tend to show more barite nodules and higher barium concentration in the fracture stimulation flowback water. The Marcellus Shale is one of the most important gas shale plays in the world as horizontal drilling and hydraulic fracturing have been extensively utilized over the last decade. Sedimentary barite is ubiquitous in the Marcellus Shale and unusually high barium concentrations tend to occur in Marcellus flow back water, which can cause serious scale formation adversely impacting well performance and environmental concerns. This study investigates the characteristics of barite in the Marcellus and provides insights on its regional distribution and origin. Barite is regionally widespread in the Marcellus, focused immediately beneath or within the Cherry Valley Member. Barite-bearing zones range in thickness from centimeters to >3 meters and tend to be thicker in the east thinning westward. Barite occurs commonly as centimeter-scale, oval-shaped nodules, especially in central and western Pennsylvania. Eastward, barite is found as poorly-defined, incipient nodules and disseminated crystal aggregates. Barite in the Marcellus commonly occurs associated with pyrite nodules and carbonate concretions. Compaction-related fabrics indicate that barite formed as a product of early diagenesis. Barite crystals in nodules are typically finely crystalline (5 – 60 µm), becoming more coarsely crystalline (60 µm to >1 mm) eastward towards the Allegheny front. ?34S values determined from barite nodules range from 34.6 to 66.6 ‰. Barite deposits in shale are often considered indicative of low sedimentation rates and may denote a hiatus in sedimentation, which can cause dilute Ba2+ to be significantly enriched by microbial activities leading to barite precipitation. Our regional analysis of over 100 cored wells in the Marcellus documents regional variability in both barite crystal size and sulfur isotopic composition. Coarsely crystalline barite displays low ?34S values when compared to finely crystalline barite which have higher ?34S values. These trends in fabric and sulfur isotope composition are attributed to variable rates of microbial sulfate reduction related to changing sedimentation rates. The high ?34S values associated with the finely crystalline barite result from a lower sedimentation rate and commensurate enhanced microbial sulfate reduction. The Tioga Ash is considered as an important source of Ba2+ in the basin and those areas with thicker ash accumulation tend to show more barite nodules and higher barium concentration in the fracture stimulation flowback water. Panel_14888 Panel_14888 8:30 AM 5:00 PM

Hydraulic fracturing for shale gas production involves injection of pressurized water and additives into shale formations to enhance permeability. Interaction between injected fluid, formation water, and minerals in the shale has the potential to drive dissolution or precipitation reactions that will alter fluid composition and potentially formation porosity and permeability. The low initial permeability of shale plays makes it critical to minimize any processes that could further reduce permeability and gas production. We use a combination of field data and geochemical modeling to predict which reactions occur down boreholes during natural gas extraction. Hydraulic fracturing fluid (HFF) and flowback water compositions were monitored in three wells in southwestern Pennsylvania and these data are used to constrain reaction path models for subsurface interaction of HFF with host rock and formation water. Speciation and solubility calculations for HFF indicate that prior to injection the fluid is oversaturated only with respect to barite and iron oxides and hydroxides. Flowback water from the same well 7 weeks after initial injection is oversaturated with respect to multiple secondary minerals, including various sulfates (barite, jarosite), carbonates (aragonite, calcite, dolomite, strontianite), iron oxides and hydroxides (goethite, hematite, magnetite), and hydrated magnesium silicates (chrysotile, talc). The development of mineral oversaturation in flowback water may be due to either reaction with the host rock or formation water. Batch reaction modeling of HFF equilibrated with typical Marcellus shale minerals (illite, calcite, quartz, chlorite, smectite, pyrite) results in near saturation with respect to strontianite and oversaturation with respect to chrysotile and talc. Mixing models for HFF and formation water predict oversaturation with the same phases that are oversaturated in flowback water, plus additional carbonates (rhodochrosite, siderite, witherite), clays (chlorite, kaolinite, montmorillonite, smectite), and aluminum hydroxide (gibbsite). These geochemical models suggest mineral precipitation within shale gas boreholes could be of concern if reactions occur in the timeframe of gas production. Kinetic limitations and effects of organic compounds on precipitation should be considered, as they may determine the timescale and significance of dissolution and precipitation resulting from down-hole fluid mixing and water-rock interaction. Hydraulic fracturing for shale gas production involves injection of pressurized water and additives into shale formations to enhance permeability. Interaction between injected fluid, formation water, and minerals in the shale has the potential to drive dissolution or precipitation reactions that will alter fluid composition and potentially formation porosity and permeability. The low initial permeability of shale plays makes it critical to minimize any processes that could further reduce permeability and gas production. We use a combination of field data and geochemical modeling to predict which reactions occur down boreholes during natural gas extraction. Hydraulic fracturing fluid (HFF) and flowback water compositions were monitored in three wells in southwestern Pennsylvania and these data are used to constrain reaction path models for subsurface interaction of HFF with host rock and formation water. Speciation and solubility calculations for HFF indicate that prior to injection the fluid is oversaturated only with respect to barite and iron oxides and hydroxides. Flowback water from the same well 7 weeks after initial injection is oversaturated with respect to multiple secondary minerals, including various sulfates (barite, jarosite), carbonates (aragonite, calcite, dolomite, strontianite), iron oxides and hydroxides (goethite, hematite, magnetite), and hydrated magnesium silicates (chrysotile, talc). The development of mineral oversaturation in flowback water may be due to either reaction with the host rock or formation water. Batch reaction modeling of HFF equilibrated with typical Marcellus shale minerals (illite, calcite, quartz, chlorite, smectite, pyrite) results in near saturation with respect to strontianite and oversaturation with respect to chrysotile and talc. Mixing models for HFF and formation water predict oversaturation with the same phases that are oversaturated in flowback water, plus additional carbonates (rhodochrosite, siderite, witherite), clays (chlorite, kaolinite, montmorillonite, smectite), and aluminum hydroxide (gibbsite). These geochemical models suggest mineral precipitation within shale gas boreholes could be of concern if reactions occur in the timeframe of gas production. Kinetic limitations and effects of organic compounds on precipitation should be considered, as they may determine the timescale and significance of dissolution and precipitation resulting from down-hole fluid mixing and water-rock interaction. Panel_14893 Panel_14893 8:30 AM 5:00 PM

Panel_14427 Panel_14427 8:30 AM 5:00 PM

The evolution of reservoir permeability is of fundamental importance in reservoir engineering. However, many of the commonly used concepts in reservoir may not be directly applicable to unconventional reservoirs due to their extremely low (and highly anisotropic) permeability, extremely small pore throat sizes. Therefore, the transport processes of compressible micro- to meso-porous rocks such as shales require a critical revision of the classical concepts. Due to the higher compressibility of shale reservoirs as compared to conventional reservoirs, some processes have to be considered as coupled such as the transition from Darcy-flow to slip-flow and the stress sensitivity of the permeability to pore throat compressibility, which is a poroelastic effect. We also develop a detailed description of the coupling between slip-flow and the stress sensitivity in unconventional reservoirs, and interpret experimental observations in light of this description. We characterize the transport properties of shales in a manner that includes a zero-effective-stress permeability coefficient, a stress sensitivity coefficient, an effective stress coefficient and slippage as a function of effective stress. We model single-phase matrix gas permeability during reservoir depletion for the Eagle Ford and Marcellus shale. This case study shows the significant influence of slip-flow, which can lead up to a two times higher permeability when the pore pressure decline below 10 MPa. Furthermore, considering the coupling between slip flow and poroelasticity in the permeability model, the permeability can be 50% higher for selected samples. The evolution of reservoir permeability is of fundamental importance in reservoir engineering. However, many of the commonly used concepts in reservoir may not be directly applicable to unconventional reservoirs due to their extremely low (and highly anisotropic) permeability, extremely small pore throat sizes. Therefore, the transport processes of compressible micro- to meso-porous rocks such as shales require a critical revision of the classical concepts. Due to the higher compressibility of shale reservoirs as compared to conventional reservoirs, some processes have to be considered as coupled such as the transition from Darcy-flow to slip-flow and the stress sensitivity of the permeability to pore throat compressibility, which is a poroelastic effect. We also develop a detailed description of the coupling between slip-flow and the stress sensitivity in unconventional reservoirs, and interpret experimental observations in light of this description. We characterize the transport properties of shales in a manner that includes a zero-effective-stress permeability coefficient, a stress sensitivity coefficient, an effective stress coefficient and slippage as a function of effective stress. We model single-phase matrix gas permeability during reservoir depletion for the Eagle Ford and Marcellus shale. This case study shows the significant influence of slip-flow, which can lead up to a two times higher permeability when the pore pressure decline below 10 MPa. Furthermore, considering the coupling between slip flow and poroelasticity in the permeability model, the permeability can be 50% higher for selected samples. Panel_14923 Panel_14923 8:30 AM 5:00 PM

For a number of decades, scientists and engineers have been investigating and describing storage and transport mechanisms in porous media such as reservoir rocks. This work has resulted in the development of concepts such as single phase and multi-phase flow, which describe the movement of fluids in conventional reservoir rock types such as sandstones and carbonates. However, many of these concepts may not be directly applicable to unconventional reservoirs. For example, shale gas reservoirs consist of organic-rich shale matrix, which have high compressibility, very small pore throats, extremely low and anisotropic porosity and permeability. The models developed to describe conventional reservoirs may not accurately describe the processes at work in these rocks. We aim to characterize the transport processes occurring in unconventional reservoirs. We will examine processes occurring at various spatial scales, ranging from fracture flow on the centimeter scale down to slip-flow on the nanometer scale. Due to the softer nature of tight shales, many processes, such as slip-flow and the pore-throat compressibility, will have to be considered as coupled. We collect more than 300 publications and interpret experimental observations in light of this description. For a number of decades, scientists and engineers have been investigating and describing storage and transport mechanisms in porous media such as reservoir rocks. This work has resulted in the development of concepts such as single phase and multi-phase flow, which describe the movement of fluids in conventional reservoir rock types such as sandstones and carbonates. However, many of these concepts may not be directly applicable to unconventional reservoirs. For example, shale gas reservoirs consist of organic-rich shale matrix, which have high compressibility, very small pore throats, extremely low and anisotropic porosity and permeability. The models developed to describe conventional reservoirs may not accurately describe the processes at work in these rocks. We aim to characterize the transport processes occurring in unconventional reservoirs. We will examine processes occurring at various spatial scales, ranging from fracture flow on the centimeter scale down to slip-flow on the nanometer scale. Due to the softer nature of tight shales, many processes, such as slip-flow and the pore-throat compressibility, will have to be considered as coupled. We collect more than 300 publications and interpret experimental observations in light of this description. Panel_14919 Panel_14919 8:30 AM 5:00 PM

Mudrock porosity is associated with both inorganic and organic matter, and hydrocarbons are found in both. The upper Eagle Ford is considered to be dominated by inorganic porosity, while the lower Eagle Ford is considered to have more organic-hosted porosity related to high organic content. The differences in inorganic versus organic pore types play a large role with regard to pore networks. This study investigates Eagle Ford mudrock pores through the use of nuclear magnetic resonance (NMR) in order to better quantify porosity values for these unconventional reservoirs. Recently, laboratory-based NMR has been used to measure fluid content and pore volume of mudrocks affordably and nondestructively. While NMR is quite versatile, important limitations exist, including the inability to directly measure pore-throat sizes or pores that are not fluid filled. However, calibration to mercury injection capillary pressure (MICP) measurements from finely grinding the same sample into powder yields interpretable results. Using a total of 28 samples from three wells in Karnes and Maverick Counties, South Texas, this study examines how pore-throat size distribution and fluid content differ vertically in the succession. The lithology and facies vary, both vertically within each well and laterally between wells. Six facies were identified among the three wells. With the aid of geochemical analysis such as XRF these lithologies can be broken down into subfacies based on calcite content and minor elements, such as molybdenum and vanadium, related to anoxia. These subfacies were used to pick the sample points. While a mixture of pore types is anticipated, samples with higher organic-hosted porosity are expected to have smaller pore throats and contain more oil. Early results indicate measurable pore throat sizes between 0.001 and 0.01 microns filled with low to medium-viscosity fluids, likely a mixture of water and oil, and intrusion corrected porosities ranging between 5.2% to 9.4% in the lower Eagle Ford. Greater heterogeneity of the pore system in the lower Eagle Ford has been confirmed through an SEM study. Using NMR to evaluate the linkage between facies changes and pore-throat-size distribution and content will aid future play-wide analysis. Mudrock porosity is associated with both inorganic and organic matter, and hydrocarbons are found in both. The upper Eagle Ford is considered to be dominated by inorganic porosity, while the lower Eagle Ford is considered to have more organic-hosted porosity related to high organic content. The differences in inorganic versus organic pore types play a large role with regard to pore networks. This study investigates Eagle Ford mudrock pores through the use of nuclear magnetic resonance (NMR) in order to better quantify porosity values for these unconventional reservoirs. Recently, laboratory-based NMR has been used to measure fluid content and pore volume of mudrocks affordably and nondestructively. While NMR is quite versatile, important limitations exist, including the inability to directly measure pore-throat sizes or pores that are not fluid filled. However, calibration to mercury injection capillary pressure (MICP) measurements from finely grinding the same sample into powder yields interpretable results. Using a total of 28 samples from three wells in Karnes and Maverick Counties, South Texas, this study examines how pore-throat size distribution and fluid content differ vertically in the succession. The lithology and facies vary, both vertically within each well and laterally between wells. Six facies were identified among the three wells. With the aid of geochemical analysis such as XRF these lithologies can be broken down into subfacies based on calcite content and minor elements, such as molybdenum and vanadium, related to anoxia. These subfacies were used to pick the sample points. While a mixture of pore types is anticipated, samples with higher organic-hosted porosity are expected to have smaller pore throats and contain more oil. Early results indicate measurable pore throat sizes between 0.001 and 0.01 microns filled with low to medium-viscosity fluids, likely a mixture of water and oil, and intrusion corrected porosities ranging between 5.2% to 9.4% in the lower Eagle Ford. Greater heterogeneity of the pore system in the lower Eagle Ford has been confirmed through an SEM study. Using NMR to evaluate the linkage between facies changes and pore-throat-size distribution and content will aid future play-wide analysis. Panel_14918 Panel_14918 8:30 AM 5:00 PM

There is controversy about the development of organic-matter (OM) pores in lower maturity organic-rich mudrocks, with some studies concluding OM pores are not formed until the gas window is reached (vitrinite reflectances > 1.3%). However, we have observed many samples in which OM pores are present in sub-1.0% vitrinite reflectance mudrocks from the Devonian New Albany Shale of the Illinois Basin (siliceous-argillaceous lithologies), the Mississippian Barnett Shale of the Fort Worth Basin (dominantly siliceous lithologies) and the Cretaceous Eagle Ford Formation from South Texas (dominantly calcareous lithologies). In these same rocks, OM pores are generally absent or rare at vitrinite reflectances less than 0.75%. Further controversy exists over being able to differentiate maturation-related OM pores from pores that remain when mobile organic matter incompletely fills pre-existing interparticle or intraparticle pores due to the presence of other fluid phases. Such pores tend to be smooth walled and larger than maturation-related OM pores and this mechanism typically forms only one or two pores in the center of an area of OM. Three cores were sampled in the Barnett, one core was sampled in the New Albany and four cores were sampled in the Eagle Ford. All samples were in the 0.75 to 1.0% vitrinite reflectance thermal maturity range. Pores were examined using a field-emission scanning electron microscope on surfaces prepared with broad-ion-beam milling using Ar-ions. OM pores observed are typically less than a micrometer in diameter. OM pore shapes are highly variable from nearly circular to highly elongate in outline. OM pore abundances are highly variable ranging from a scattered few to densely concentrated spongy patches. Differences in pore size, shape, and abundance may be related to underlying differences in the composition and structure of the original OM. OM pores are overall lower in abundance in sub-1.0% vitrinite reflectance mudrocks than in more mature mudrocks. However, heterogeneity of pore development is such that nonporous to highly porous organic matter is found across a range of thermal maturities. Variation occurs both within and between samples. There is controversy about the development of organic-matter (OM) pores in lower maturity organic-rich mudrocks, with some studies concluding OM pores are not formed until the gas window is reached (vitrinite reflectances > 1.3%). However, we have observed many samples in which OM pores are present in sub-1.0% vitrinite reflectance mudrocks from the Devonian New Albany Shale of the Illinois Basin (siliceous-argillaceous lithologies), the Mississippian Barnett Shale of the Fort Worth Basin (dominantly siliceous lithologies) and the Cretaceous Eagle Ford Formation from South Texas (dominantly calcareous lithologies). In these same rocks, OM pores are generally absent or rare at vitrinite reflectances less than 0.75%. Further controversy exists over being able to differentiate maturation-related OM pores from pores that remain when mobile organic matter incompletely fills pre-existing interparticle or intraparticle pores due to the presence of other fluid phases. Such pores tend to be smooth walled and larger than maturation-related OM pores and this mechanism typically forms only one or two pores in the center of an area of OM. Three cores were sampled in the Barnett, one core was sampled in the New Albany and four cores were sampled in the Eagle Ford. All samples were in the 0.75 to 1.0% vitrinite reflectance thermal maturity range. Pores were examined using a field-emission scanning electron microscope on surfaces prepared with broad-ion-beam milling using Ar-ions. OM pores observed are typically less than a micrometer in diameter. OM pore shapes are highly variable from nearly circular to highly elongate in outline. OM pore abundances are highly variable ranging from a scattered few to densely concentrated spongy patches. Differences in pore size, shape, and abundance may be related to underlying differences in the composition and structure of the original OM. OM pores are overall lower in abundance in sub-1.0% vitrinite reflectance mudrocks than in more mature mudrocks. However, heterogeneity of pore development is such that nonporous to highly porous organic matter is found across a range of thermal maturities. Variation occurs both within and between samples. Panel_14928 Panel_14928 8:30 AM 5:00 PM

Wettability of pore surfaces in organic-rich shales can significantly affect the relative distribution, storage, and productivity of gas and oil in these lithologies. Changes in organic matter structure during thermal maturation will affect its surface chemistry, therefore changing the wettability, as indicated by our recent experiments on methane and water vapor sorption. Consequently, the relative distribution of gas, oil, and water in shale systems is closely related to the thermal maturation of organic matter. An immature sample of the Woodford Shale was prepared by hydrous pyrolysis at five different time-temperature conditions to generate a suite of samples having different thermal maturities. Methane (CH4) adsorption isotherms were measured on the moisture-equilibrated and dry samples at 35°C and pressures up to 14MPa. Nitrogen and water vapor adsorption experiments were also conducted on the dry samples to characterize the pore-size distribution, surface area, and surface wettability. Water distribution and morphology were observed for these samples under various vapor pressure conditions with environmental SEM (ESEM). Comparison of water-wet and dry samples shows that moisture added to the system does not substantially reduce CH4 adsorption. This is consistent with observations from water vapor sorption isotherms that indicate the dominant hydrophobic nature of all the samples. However, the reduction of CH4 adsorption capacity is larger for the samples in the late oil-generation (367°C/72 hr, 40% reduction) and early oil-cracking (400 °C/72 hr, 53% reduction) stages compared to the early bitumen (300 °C/72 hr, 35% reduction) and maximum bitumen (333 °C/72 hr, 34% reduction) generation stages. These findings suggest that although organic matter is generally hydrophobic, there is a wettability trend for the organic matter of the studied samples that correlates with higher thermal maturity stages. These stages of petroleum formation are notably associated with the formation of insoluble hydrocarbon residue or pyrobitumen. In addition, the distribution and morphology of water observed by ESEM illustrates the increase in wettability of the high-maturity samples. This provides further evidence that pyrobitumen may play an important role in controlling the wettability of organic matter. These results also suggest that whole-rock wettability may be a useful proxy for determining the proportion of kerogen, bitumen, and pyrobitumen in shales. Wettability of pore surfaces in organic-rich shales can significantly affect the relative distribution, storage, and productivity of gas and oil in these lithologies. Changes in organic matter structure during thermal maturation will affect its surface chemistry, therefore changing the wettability, as indicated by our recent experiments on methane and water vapor sorption. Consequently, the relative distribution of gas, oil, and water in shale systems is closely related to the thermal maturation of organic matter. An immature sample of the Woodford Shale was prepared by hydrous pyrolysis at five different time-temperature conditions to generate a suite of samples having different thermal maturities. Methane (CH₄) adsorption isotherms were measured on the moisture-equilibrated and dry samples at 35°C and pressures up to 14MPa. Nitrogen and water vapor adsorption experiments were also conducted on the dry samples to characterize the pore-size distribution, surface area, and surface wettability. Water distribution and morphology were observed for these samples under various vapor pressure conditions with environmental SEM (ESEM). Comparison of water-wet and dry samples shows that moisture added to the system does not substantially reduce CH₄ adsorption. This is consistent with observations from water vapor sorption isotherms that indicate the dominant hydrophobic nature of all the samples. However, the reduction of CH₄ adsorption capacity is larger for the samples in the late oil-generation (367°C/72 hr, 40% reduction) and early oil-cracking (400 °C/72 hr, 53% reduction) stages compared to the early bitumen (300 °C/72 hr, 35% reduction) and maximum bitumen (333 °C/72 hr, 34% reduction) generation stages. These findings suggest that although organic matter is generally hydrophobic, there is a wettability trend for the organic matter of the studied samples that correlates with higher thermal maturity stages. These stages of petroleum formation are notably associated with the formation of insoluble hydrocarbon residue or pyrobitumen. In addition, the distribution and morphology of water observed by ESEM illustrates the increase in wettability of the high-maturity samples. This provides further evidence that pyrobitumen may play an important role in controlling the wettability of organic matter. These results also suggest that whole-rock wettability may be a useful proxy for determining the proportion of kerogen, bitumen, and pyrobitumen in shales. Panel_14920 Panel_14920 8:30 AM 5:00 PM

Analyses of organic-rich mudstones from three wells that penetrated the Marcellus Shale in West Virginia and Pennsylvania were performed to evaluate the nature of pore structure (porosity and permeability) in both organic matter (OM) and inorganic matrix (IM). Samples include 32 core plugs with different levels of thermal maturity and TOC from Mahantango Formation and Marcellus Shale. For each sample, 10 to 15 SEM images were digitalized to quantify shape, size, and SEM-visible porosity. Also, X-ray Fluorescence (XRF) was conducted on every sample and converted to weight percent of quartz and feldspar, clay, and carbonate to study the heterogeneity and the influence of the inorganic matrix (IM) on pore structure and SEM-visible porosity. Pore types are categorized according to the shape and location. Inter-clay-particle (also referred to as phyllosilicate framework) pores and spongy pores are the most ubiquitous pore type in IM and OM respectively. Inter-clay-particle pores usually show triangular or elongate shapes. Their sizes are from tens to hundreds of nanometers. Spongy pores in OM are usually roundish, and show a relatively uniform size in a single OM particle. Their sizes range from ten (resolution-limitation) to several hundreds of nanometers. We defined OM degradation index (OMDI) to describe the extent of development of OM pores, which is porosity in organic matter divided by whole area OM covered and the voids in it. There is no systematic change in SEM-visible porosity as a function of the abundance of OM. However, there is a negative correlation between abundance of OM and OMDI. Samples with higher content of OM usually have large OM particles without pores, which can be explained by differences of maceral types. The ten nanometer-per-pixel resolution of the SEM could hinder recognition of smaller pores. The stratigraphic distribution of pore structure in the Mahantango, upper Marcellus, and lower Marcellus is strongly affected by heterogeneity of mineral composition. OMDI indicates a positive correlation between thermal maturity and development of OM pores in lower Marcellus, which hasn’t been found in other formations. OM pores have been considered as a secondary pore type that formed during post-depositional process primarily affected by thermal maturity. However, the derivation and supply of different maceral types exert a significant control on development of porosity in organic-rich Marcellus Shale. Analyses of organic-rich mudstones from three wells that penetrated the Marcellus Shale in West Virginia and Pennsylvania were performed to evaluate the nature of pore structure (porosity and permeability) in both organic matter (OM) and inorganic matrix (IM). Samples include 32 core plugs with different levels of thermal maturity and TOC from Mahantango Formation and Marcellus Shale. For each sample, 10 to 15 SEM images were digitalized to quantify shape, size, and SEM-visible porosity. Also, X-ray Fluorescence (XRF) was conducted on every sample and converted to weight percent of quartz and feldspar, clay, and carbonate to study the heterogeneity and the influence of the inorganic matrix (IM) on pore structure and SEM-visible porosity. Pore types are categorized according to the shape and location. Inter-clay-particle (also referred to as phyllosilicate framework) pores and spongy pores are the most ubiquitous pore type in IM and OM respectively. Inter-clay-particle pores usually show triangular or elongate shapes. Their sizes are from tens to hundreds of nanometers. Spongy pores in OM are usually roundish, and show a relatively uniform size in a single OM particle. Their sizes range from ten (resolution-limitation) to several hundreds of nanometers. We defined OM degradation index (OMDI) to describe the extent of development of OM pores, which is porosity in organic matter divided by whole area OM covered and the voids in it. There is no systematic change in SEM-visible porosity as a function of the abundance of OM. However, there is a negative correlation between abundance of OM and OMDI. Samples with higher content of OM usually have large OM particles without pores, which can be explained by differences of maceral types. The ten nanometer-per-pixel resolution of the SEM could hinder recognition of smaller pores. The stratigraphic distribution of pore structure in the Mahantango, upper Marcellus, and lower Marcellus is strongly affected by heterogeneity of mineral composition. OMDI indicates a positive correlation between thermal maturity and development of OM pores in lower Marcellus, which hasn’t been found in other formations. OM pores have been considered as a secondary pore type that formed during post-depositional process primarily affected by thermal maturity. However, the derivation and supply of different maceral types exert a significant control on development of porosity in organic-rich Marcellus Shale. Panel_14925 Panel_14925 8:30 AM 5:00 PM

The Late Triassic (Norian) Dan River basin is a continuous gas assessment unit (AU) and a total petroleum system. The source rocks (Walnut Cove and Cow Branch Formations) are thick grey and black freshwater shales; the stratigraphically lower Walnut Cove Fm. has a thin basal coal. These lacustrine strata were deposited in a rift basin near the paleo-equator after Pangea’s breakup. The AU has an estimated mean gas content of 49 BCFG, and a natural gas liquids content of 0 MMBNGL (USGS Fact Sheet 2012 - 3075) based on limited 2011 data. The Walnut Cove Fm. is up to 600 feet thick with an outcrop strike of ~22 miles and a width of several miles. The Cow Branch Fm., up to 1,500 feet thick, is exposed in broad patches in Stokes and Rockingham counties, NC, and isolated localities in southernmost Virginia. The hydrocarbon potential of these two formations as shale gas reservoirs was characterized from diamond drill core hole SO-C-2-81 (Walnut Cove Fm.), and the Cow Branch Fm. exposed continuously in the Ararat (aka Solite or Cemex) quarry. Characterization results reported herein include substantial new data not available for the 2011 USGS assessment. They are: 1) organic geochemistry and thermal maturation data (doubling the 2011 data set); 2) down hole XRD whole rock mineralogy for Walnut Cove Fm., n= 34, outcrop whole rock XRD for the Cow Branch Fm., n = 13; 3) rock mechanics including triaxial compressive strength tests with acoustic velocities, pre- and post CT scans, and Young’s Modulus and Poisson’s Ratio (Walnut Cove Fm., n = 7, Cow Branch Fm., n = 13); 4) mercury injection capillary pressure data obtained to characterize porosity and permeability in the both formations (Walnut Cove Fm., n = 14, Cow Branch Fm., n = 27) with maximum pressure of 60,000 psia providing a pore aperture frequency distribution down to nanometer-scale diameter; and 5) pore characterization using SEM and ion beam milled samples. This is the third report characterizing the continental Triassic rift / lacustrine deposits in NC. Previous reports on the time equivalent Cumnock Fm., Deep River basin, NC, are available on ‘Search and Discovery’. The Cumnock Fm. consists of black organic-rich mudrocks with significant porosity. Initial results from characterizing these formations show them as petroleum source rocks (wt% TOC > 2.0). Mineralogical composition varies among the three different mudrocks, which likely has implications for inter- and intra-particle porosity trends. The Late Triassic (Norian) Dan River basin is a continuous gas assessment unit (AU) and a total petroleum system. The source rocks (Walnut Cove and Cow Branch Formations) are thick grey and black freshwater shales; the stratigraphically lower Walnut Cove Fm. has a thin basal coal. These lacustrine strata were deposited in a rift basin near the paleo-equator after Pangea’s breakup. The AU has an estimated mean gas content of 49 BCFG, and a natural gas liquids content of 0 MMBNGL (USGS Fact Sheet 2012 - 3075) based on limited 2011 data. The Walnut Cove Fm. is up to 600 feet thick with an outcrop strike of ~22 miles and a width of several miles. The Cow Branch Fm., up to 1,500 feet thick, is exposed in broad patches in Stokes and Rockingham counties, NC, and isolated localities in southernmost Virginia. The hydrocarbon potential of these two formations as shale gas reservoirs was characterized from diamond drill core hole SO-C-2-81 (Walnut Cove Fm.), and the Cow Branch Fm. exposed continuously in the Ararat (aka Solite or Cemex) quarry. Characterization results reported herein include substantial new data not available for the 2011 USGS assessment. They are: 1) organic geochemistry and thermal maturation data (doubling the 2011 data set); 2) down hole XRD whole rock mineralogy for Walnut Cove Fm., n= 34, outcrop whole rock XRD for the Cow Branch Fm., n = 13; 3) rock mechanics including triaxial compressive strength tests with acoustic velocities, pre- and post CT scans, and Young’s Modulus and Poisson’s Ratio (Walnut Cove Fm., n = 7, Cow Branch Fm., n = 13); 4) mercury injection capillary pressure data obtained to characterize porosity and permeability in the both formations (Walnut Cove Fm., n = 14, Cow Branch Fm., n = 27) with maximum pressure of 60,000 psia providing a pore aperture frequency distribution down to nanometer-scale diameter; and 5) pore characterization using SEM and ion beam milled samples. This is the third report characterizing the continental Triassic rift / lacustrine deposits in NC. Previous reports on the time equivalent Cumnock Fm., Deep River basin, NC, are available on ‘Search and Discovery’. The Cumnock Fm. consists of black organic-rich mudrocks with significant porosity. Initial results from characterizing these formations show them as petroleum source rocks (wt% TOC > 2.0). Mineralogical composition varies among the three different mudrocks, which likely has implications for inter- and intra-particle porosity trends. Panel_14930 Panel_14930 8:30 AM 5:00 PM

The gases that fill nanoscale pores in organic-rich shales can be released during crushing. Our results show that both thermal maturity and gas desorption contribute to changes in the CH4/CO2 ratio of gases released during rock crushing. CH4/CO2 ratios of these gases are lower at low thermal maturities and higher at high thermal maturities because more CH4-rich gas is generated at higher maturity levels. However, no obvious compositional fractionation occurs among C1, C2, and C3 of crushed-rock gas, and C1/C2 and C2/C3 ratios remain nearly constant during crushing although these ratios are greatly increased overall when the level of thermal maturity is high. Gas geochemical parameters (C1/C2, C2/C3, and i-C4/n-C4) of released gas are good indicators of thermal maturation of organic-rich shales. Gas yields from a set of samples of varied TOC content but uniform thermal maturity, vary directly with TOC and porosity, suggesting greater pore connectivity for high TOC samples because of the development of organic matter-hosted pores critical to gas storage and deliverability. Trends in released gas yield and gas chemistry during rock crushing relate to gas storage states and pore connectivity. The d13C1, d13C2 and d13C3 values of gas released from particles of coarser size (> 250 µm) are similar to values of gas produced from Barnett shales after hydraulic fracturing. CH4-dominated gas appears to be stored in larger connected pores and is therefore released during the initial stages of crushing. The carbon-isotope values of C1, C2, and C3 are heavier in the more thermally mature samples, suggesting that this released gas is representative of the gas chemistry of the subsurface reservoir. Released gases provide a basis for understanding reservoir gas compositions and saturations even in older cores, bridging a gap caused by the scarcity of desorption data from fresh canister core. Chemical and isotopic composition of the released gases is an indicator of thermal maturity in subsurface reservoirs, and retained gas yield is directly related to variations of lithology and pore connectivity. This new method can provide useful information to evaluate gas storage and deliverability when old cores are available. The gases that fill nanoscale pores in organic-rich shales can be released during crushing. Our results show that both thermal maturity and gas desorption contribute to changes in the CH₄/CO₂ ratio of gases released during rock crushing. CH₄/CO₂ ratios of these gases are lower at low thermal maturities and higher at high thermal maturities because more CH₄-rich gas is generated at higher maturity levels. However, no obvious compositional fractionation occurs among C1, C2, and C3 of crushed-rock gas, and C1/C2 and C2/C3 ratios remain nearly constant during crushing although these ratios are greatly increased overall when the level of thermal maturity is high. Gas geochemical parameters (C1/C2, C2/C3, and i-C4/n-C4) of released gas are good indicators of thermal maturation of organic-rich shales. Gas yields from a set of samples of varied TOC content but uniform thermal maturity, vary directly with TOC and porosity, suggesting greater pore connectivity for high TOC samples because of the development of organic matter-hosted pores critical to gas storage and deliverability. Trends in released gas yield and gas chemistry during rock crushing relate to gas storage states and pore connectivity. The d13C1, d13C2 and d13C3 values of gas released from particles of coarser size (> 250 µm) are similar to values of gas produced from Barnett shales after hydraulic fracturing. CH₄-dominated gas appears to be stored in larger connected pores and is therefore released during the initial stages of crushing. The carbon-isotope values of C1, C2, and C3 are heavier in the more thermally mature samples, suggesting that this released gas is representative of the gas chemistry of the subsurface reservoir. Released gases provide a basis for understanding reservoir gas compositions and saturations even in older cores, bridging a gap caused by the scarcity of desorption data from fresh canister core. Chemical and isotopic composition of the released gases is an indicator of thermal maturity in subsurface reservoirs, and retained gas yield is directly related to variations of lithology and pore connectivity. This new method can provide useful information to evaluate gas storage and deliverability when old cores are available. Panel_14929 Panel_14929 8:30 AM 5:00 PM

The Cretaceous Mowry Shale in the Powder River Basin (PRB), WY is a well-known hydrocarbon source for overlying Frontier and underlying Muddy sandstones. Recent studies have focused on the hydrocarbon potential of the Mowry formation as an unconventional reservoir. It consists of primarily siliceous black shale which can be subdivided into three intervals: a fissile, weakly cemented, bioturbated shale at the bottom; highly siliceous, thinly laminated, organic-matter-enriched shale in the middle; and a coarsening upward, bioturbated silty-shale in the upper section. Twelve primary bentonite beds are distributed throughout the Mowry section and can be correlated across the PRB. Investigation of cores, drill stem test, production data, rock evaluation and sequence stratigraphy indicates two ideal drill intervals within the middle Mowry section. The lateral continuity of these two zones and the correlation between bentonites provide further work on the facies changes and deformational structures across the PRB to find ideal drill locations. In this study, we utilize computed tomography (CT) and scanning electron microscope (SEM) to better understand the heterogeneity of pore space and fracture networks at varying depths in the PRB. CT and SEM analysis of available core samples within the potential drilling intervals provide critical information about micron-to-nanometer scale characteristics of the Mowry shale. A detailed fracture analysis yields a structural model to explain the potential tectonic effects on pore space evolution. Sampling across facies changes within the drilling interval will help develop an understanding of the effect that variations in depositional minerals or material have on pore space. The results of this study will show changes in granular and organic-matter-hosted pore space, pore throat size and effective permeability due to both structural deformation and variations in sedimentation. The major contribution of this study is to provide a better understanding for successful drilling practices in unconventional black shale and clay rich hydrocarbon resources. The Cretaceous Mowry Shale in the Powder River Basin (PRB), WY is a well-known hydrocarbon source for overlying Frontier and underlying Muddy sandstones. Recent studies have focused on the hydrocarbon potential of the Mowry formation as an unconventional reservoir. It consists of primarily siliceous black shale which can be subdivided into three intervals: a fissile, weakly cemented, bioturbated shale at the bottom; highly siliceous, thinly laminated, organic-matter-enriched shale in the middle; and a coarsening upward, bioturbated silty-shale in the upper section. Twelve primary bentonite beds are distributed throughout the Mowry section and can be correlated across the PRB. Investigation of cores, drill stem test, production data, rock evaluation and sequence stratigraphy indicates two ideal drill intervals within the middle Mowry section. The lateral continuity of these two zones and the correlation between bentonites provide further work on the facies changes and deformational structures across the PRB to find ideal drill locations. In this study, we utilize computed tomography (CT) and scanning electron microscope (SEM) to better understand the heterogeneity of pore space and fracture networks at varying depths in the PRB. CT and SEM analysis of available core samples within the potential drilling intervals provide critical information about micron-to-nanometer scale characteristics of the Mowry shale. A detailed fracture analysis yields a structural model to explain the potential tectonic effects on pore space evolution. Sampling across facies changes within the drilling interval will help develop an understanding of the effect that variations in depositional minerals or material have on pore space. The results of this study will show changes in granular and organic-matter-hosted pore space, pore throat size and effective permeability due to both structural deformation and variations in sedimentation. The major contribution of this study is to provide a better understanding for successful drilling practices in unconventional black shale and clay rich hydrocarbon resources. Panel_14921 Panel_14921 8:30 AM 5:00 PM

The Niobrara member of the Mancos Shale is an unconventional gas reservoir in the Piceance basin, western Colorado. In general, burial and thermal histories were less on the western side of the basin and greater in the northeastern side of the basin. As a result, vitrinite reflectance values for the full Niobrara interval range from ~0.5 Ro to ~1.2 Ro. This study investigates how nano- and micron-scale pore systems differ as a result of this variability in thermal histories. Core material was sampled from 6 wells that cover a 6,750 ft range in subsea burial depths and Ro values of 0.5 to 0.9. To control for lithologic heterogeneity, all samples were taken from the same ~50 ft-thick stratigraphic interval that comprises the primary horizontal landing zone across the basin. Lithologies in that zone are marls to marly shales with reasonably high (up to ~55%) carbonate content. The primary constituents are quartz silt, peloids, and argillaceous clays. Elemental mapping shows that peloids are almost exclusively calcite and contain disseminated carbon. Detrital carbon (kerogen) and siliciclastics are in the matrix. Pore networks were identified, characterized, and analyzed using focused ion-beam scanning electron microscopy (FIB-SEM) and Avizo Firetm image analysis software. A variety of pore types were observed, with the dominant forms being intercrystalline pores between recrystallized calcite in the peloids and clay-related plus interparticle pores in the intervening argillaceous matrix. At one point in time the average amount of porosity in peloids (13%) was 6 times greater than the average amount in matrix (2.2%). But many of those pores (70% in peloids, 60% in matrix) are now filled with residual migrated hydrocarbons that contain organic matter bubble pores (~7% of all residual hydrocarbon is now bubble pore). As a result, total imaged porosity now averages only 3.5% in peloids and 0.9% in matrix with OM pores comprising 10% to 20% of those values. Cumulative area and size distributions (equivalent circular diameters average 257.6 nm in peloids and 266.2 nm in matrix) for peloids and matrix pore networks show no trend related to burial depth or thermal history. The lowest maturity well (~0.5 % Ro) shows a much lower abundance of organic matter porosity relative to all other wells, but there is no trend in organic matter porosity above a Ro of ~0.7. The Niobrara member of the Mancos Shale is an unconventional gas reservoir in the Piceance basin, western Colorado. In general, burial and thermal histories were less on the western side of the basin and greater in the northeastern side of the basin. As a result, vitrinite reflectance values for the full Niobrara interval range from ~0.5 Ro to ~1.2 Ro. This study investigates how nano- and micron-scale pore systems differ as a result of this variability in thermal histories. Core material was sampled from 6 wells that cover a 6,750 ft range in subsea burial depths and Ro values of 0.5 to 0.9. To control for lithologic heterogeneity, all samples were taken from the same ~50 ft-thick stratigraphic interval that comprises the primary horizontal landing zone across the basin. Lithologies in that zone are marls to marly shales with reasonably high (up to ~55%) carbonate content. The primary constituents are quartz silt, peloids, and argillaceous clays. Elemental mapping shows that peloids are almost exclusively calcite and contain disseminated carbon. Detrital carbon (kerogen) and siliciclastics are in the matrix. Pore networks were identified, characterized, and analyzed using focused ion-beam scanning electron microscopy (FIB-SEM) and Avizo Firetm image analysis software. A variety of pore types were observed, with the dominant forms being intercrystalline pores between recrystallized calcite in the peloids and clay-related plus interparticle pores in the intervening argillaceous matrix. At one point in time the average amount of porosity in peloids (13%) was 6 times greater than the average amount in matrix (2.2%). But many of those pores (70% in peloids, 60% in matrix) are now filled with residual migrated hydrocarbons that contain organic matter bubble pores (~7% of all residual hydrocarbon is now bubble pore). As a result, total imaged porosity now averages only 3.5% in peloids and 0.9% in matrix with OM pores comprising 10% to 20% of those values. Cumulative area and size distributions (equivalent circular diameters average 257.6 nm in peloids and 266.2 nm in matrix) for peloids and matrix pore networks show no trend related to burial depth or thermal history. The lowest maturity well (~0.5 % Ro) shows a much lower abundance of organic matter porosity relative to all other wells, but there is no trend in organic matter porosity above a Ro of ~0.7. Panel_14917 Panel_14917 8:30 AM 5:00 PM

It has been postulated that hydraulic fractures reactivate natural fracture networks, resulting in greater access to the host rock and increased rates of production. However, many of these natural fractures are completely-cemented, and currently there is very little evidence that completely-cemented natural fractures are anything but impermeable, and thus would block production. Among natural fractures observed in core of Eagle Ford Shale, Texas, tall sub-vertical calcite-cemented fractures were the focus of this investigation. Similar sub-vertical, completely-cemented, opening-mode fractures are very common in mudrocks. We used SEM imaging on broad-ion-beam (BIB)-milled samples of a calcite-cemented fracture to study the microstructure of the calcite for any indication that completely cemented fractures are permeable. In the fracture calcite cement, we observed open flow-paths between calcite grains that are generally well-connected with an average aperture between ~25 and ~100 nm. The permeability of these flow-paths was determined by lattice Boltzmann methods to be between 60 to 660 µD. These flow-paths have a spacing between 200 and 400 µm; therefore, a square centimeter (length*height) of fracture cement will contain on average more than 500 flow-paths. Using simple effective medium upscaling the fracture cement studied here is found to have a permeability in the range of 30 to 630 nD. Although this is a very low permeability, it is within the range of the permeability of typical mudrocks; therefore, these calcite cements would have almost no effect on flow orthogonal to the plane of the fracture. These flow-paths are also connected within the calcite cement creating a flow-path network along the fracture. Although the flow-path network has a bulk permeability close to that of typical mudrocks, due to the much lower porosity of the calcite cement (< 0.05%) in comparison to the host rock (2% < typical mudrock porosity < 15%) the actual velocities in the flow-path network are much greater than the host rock. During production, the significantly greater actual velocities of flow in the cemented natural fracture results in the lower pressure of the wellbore-hydraulic-fracture being quickly translated into the natural fracture. This will effectively increase the hydraulic fracture/host rock interfacial area, and production rates. Therefore, completely-cemented natural fractures in mudrocks can act as flow highways. It has been postulated that hydraulic fractures reactivate natural fracture networks, resulting in greater access to the host rock and increased rates of production. However, many of these natural fractures are completely-cemented, and currently there is very little evidence that completely-cemented natural fractures are anything but impermeable, and thus would block production. Among natural fractures observed in core of Eagle Ford Shale, Texas, tall sub-vertical calcite-cemented fractures were the focus of this investigation. Similar sub-vertical, completely-cemented, opening-mode fractures are very common in mudrocks. We used SEM imaging on broad-ion-beam (BIB)-milled samples of a calcite-cemented fracture to study the microstructure of the calcite for any indication that completely cemented fractures are permeable. In the fracture calcite cement, we observed open flow-paths between calcite grains that are generally well-connected with an average aperture between ~25 and ~100 nm. The permeability of these flow-paths was determined by lattice Boltzmann methods to be between 60 to 660 µD. These flow-paths have a spacing between 200 and 400 µm; therefore, a square centimeter (length*height) of fracture cement will contain on average more than 500 flow-paths. Using simple effective medium upscaling the fracture cement studied here is found to have a permeability in the range of 30 to 630 nD. Although this is a very low permeability, it is within the range of the permeability of typical mudrocks; therefore, these calcite cements would have almost no effect on flow orthogonal to the plane of the fracture. These flow-paths are also connected within the calcite cement creating a flow-path network along the fracture. Although the flow-path network has a bulk permeability close to that of typical mudrocks, due to the much lower porosity of the calcite cement (< 0.05%) in comparison to the host rock (2% < typical mudrock porosity < 15%) the actual velocities in the flow-path network are much greater than the host rock. During production, the significantly greater actual velocities of flow in the cemented natural fracture results in the lower pressure of the wellbore-hydraulic-fracture being quickly translated into the natural fracture. This will effectively increase the hydraulic fracture/host rock interfacial area, and production rates. Therefore, completely-cemented natural fractures in mudrocks can act as flow highways. Panel_14924 Panel_14924 8:30 AM 5:00 PM

Knowledge of mudstone permeability and sensitivity to stress is required to enhance interpretation of well logs and subsurface variability. This project provides an integrated study of both lab-measured permeability and mechanical properties, and sedimentological, diagenetic and burial histories of mudstones. Samples tested include a Jurassic mudstone (Whitby Mudstone Formation), a clay-bearing, silt-rich mudstone with 6-9% porosity, 1.5% TOC and an anisotropic texture. Samples from the carbonate-rich Eagle Ford Formation and clay-rich Marcellus Formation are also being tested to examine the relationship between permeability and porosity and the microstructural arrangement and elasticity of the component mineral phases in these different mudstones. Permeability was measured as a function of effective pressure (Peff ) for flow of argon across 25 mm diameter cylindrical samples, using the oscillating pore pressure method. Alongside experiments, petrographical characterization of samples is used to explore the geological controls on fluid transport properties of mudstones. A large number of experiments have been performed that demonstrate the effect of pressure cycling on mudstone permeability and as a result the intrinsic sensitivity of permeability to variations in effective stress. Further, the validity of the effective pressure concept as defined by Terzaghi (1923) as simply the difference between total confining pressure and pore pressure has also been investigated by comparing variations of pore pressure under constant confining pressure with variations of confining pressure under constant pore pressure. Crucial to gas reservoir evaluation, results show that after reconditioning, variation of permeability with Peff is reproducible, and can be used to model the reduction in gas flow to be expected as a result of the increased Peff that results from in-situ pore pressure decay during gas extraction. Additionally, the influence of (hydrostatic) effective confining pressure on permeability, defined by the traditional effective stress law, must be modified by an additional term that depends only on pore pressure, of the form log k = A + Peff + b Pp where k is permeability, Peff is effective pressure, Pp is pore pressure and A and b are parameters. Such an approach is essential to the realistic application of laboratory-determined permeability data to gas reservoir evaluation. Knowledge of mudstone permeability and sensitivity to stress is required to enhance interpretation of well logs and subsurface variability. This project provides an integrated study of both lab-measured permeability and mechanical properties, and sedimentological, diagenetic and burial histories of mudstones. Samples tested include a Jurassic mudstone (Whitby Mudstone Formation), a clay-bearing, silt-rich mudstone with 6-9% porosity, 1.5% TOC and an anisotropic texture. Samples from the carbonate-rich Eagle Ford Formation and clay-rich Marcellus Formation are also being tested to examine the relationship between permeability and porosity and the microstructural arrangement and elasticity of the component mineral phases in these different mudstones. Permeability was measured as a function of effective pressure (Peff ) for flow of argon across 25 mm diameter cylindrical samples, using the oscillating pore pressure method. Alongside experiments, petrographical characterization of samples is used to explore the geological controls on fluid transport properties of mudstones. A large number of experiments have been performed that demonstrate the effect of pressure cycling on mudstone permeability and as a result the intrinsic sensitivity of permeability to variations in effective stress. Further, the validity of the effective pressure concept as defined by Terzaghi (1923) as simply the difference between total confining pressure and pore pressure has also been investigated by comparing variations of pore pressure under constant confining pressure with variations of confining pressure under constant pore pressure. Crucial to gas reservoir evaluation, results show that after reconditioning, variation of permeability with Peff is reproducible, and can be used to model the reduction in gas flow to be expected as a result of the increased Peff that results from in-situ pore pressure decay during gas extraction. Additionally, the influence of (hydrostatic) effective confining pressure on permeability, defined by the traditional effective stress law, must be modified by an additional term that depends only on pore pressure, of the form log k = A + Peff + b Pp where k is permeability, Peff is effective pressure, Pp is pore pressure and A and b are parameters. Such an approach is essential to the realistic application of laboratory-determined permeability data to gas reservoir evaluation. Panel_14922 Panel_14922 8:30 AM 5:00 PM

High-resolution microscopy enables the investigation of petrophysical properties of reservoir rocks at the pore scale, even in the case of mudrocks with pores as small as 1-10 nm across. However, tying these nanometer scale findings to longer length scales is challenging. Because of the heterogeneity of micro- and nano-scale rock properties for mudrocks, uninformed sampling can give results that are not representative at longer scales. A reasonable workflow strategy is to image samples at a course scale and then perform higher resolution imaging of representative zones. This has been proposed, and executed in limited cases, but doing so requires painstaking effort to track sample orientation and position in order to locate and image the targeted features manually. We have developed and demonstrate here a software platform that simplifies this critical task. Chiefly, the software platform is designed to use image data from any prior experiment to inform and guide targeted imaging for a subsequent experiment. We have identified and then implemented four key components to streamline this workflow. First, the system must manipulate and display disparate image data, which will likely come from a variety of microscopy techniques. Second, the platform must enable the user to properly register disparate image data to unify them in one common frame of reference. Third, the platform must be stage position-aware and capable of driving the stage to user-targeted areas of interest. Finally, the platform should present the high-resolution imagery in the context of the coarser data. Some of these requirements have been addressed individually, but they have never been integrated such that the coarse data can guide the high-resolution data collection. Prior to this work, an existing software platform could visualize various image types, and furthermore, it already had stage awareness. We demonstrate the addition of a highly flexible image registration tool that permits registration of 2D images, allowing translation, rotation, scaling, and shearing. We extended this to 3D with a common plane identification tool; once that plane is determined, the remaining alignment is carried out as a straightforward 2D registration problem. We demonstrate here this platform on various mudrock samples. We show integration of multiple imaging techniques for mudrocks spanning many orders of length scale (from mm to nm) and incorporating both 2D and 3D imaging and analysis. High-resolution microscopy enables the investigation of petrophysical properties of reservoir rocks at the pore scale, even in the case of mudrocks with pores as small as 1-10 nm across. However, tying these nanometer scale findings to longer length scales is challenging. Because of the heterogeneity of micro- and nano-scale rock properties for mudrocks, uninformed sampling can give results that are not representative at longer scales. A reasonable workflow strategy is to image samples at a course scale and then perform higher resolution imaging of representative zones. This has been proposed, and executed in limited cases, but doing so requires painstaking effort to track sample orientation and position in order to locate and image the targeted features manually. We have developed and demonstrate here a software platform that simplifies this critical task. Chiefly, the software platform is designed to use image data from any prior experiment to inform and guide targeted imaging for a subsequent experiment. We have identified and then implemented four key components to streamline this workflow. First, the system must manipulate and display disparate image data, which will likely come from a variety of microscopy techniques. Second, the platform must enable the user to properly register disparate image data to unify them in one common frame of reference. Third, the platform must be stage position-aware and capable of driving the stage to user-targeted areas of interest. Finally, the platform should present the high-resolution imagery in the context of the coarser data. Some of these requirements have been addressed individually, but they have never been integrated such that the coarse data can guide the high-resolution data collection. Prior to this work, an existing software platform could visualize various image types, and furthermore, it already had stage awareness. We demonstrate the addition of a highly flexible image registration tool that permits registration of 2D images, allowing translation, rotation, scaling, and shearing. We extended this to 3D with a common plane identification tool; once that plane is determined, the remaining alignment is carried out as a straightforward 2D registration problem. We demonstrate here this platform on various mudrock samples. We show integration of multiple imaging techniques for mudrocks spanning many orders of length scale (from mm to nm) and incorporating both 2D and 3D imaging and analysis. Panel_14927 Panel_14927 8:30 AM 5:00 PM

Laminar flow theory predicts a strong correlation between permeability and pore-throat distribution as revealed by Mercury Injection Capillary Pressure (MICP) data. Previous studies have developed relationships between MICP data and permeability; however, the permeabilities predicted by different methods can differ substantially from the measured permeabilities and from each other, especially in low permeability samples of interest for unconventional reservoirs. The purposes of this study are to evaluate why there is such large scatter, identify algorithms that best predict permeability over a wide range of permeabilities, and evaluate what type of permeability is actually measured by MICP data. Precision of permeability predictions is low due to insufficient MICP pressure measurements, assumption of MICP curve shape, permeability anisotropy of geological samples, and low precision and accuracy of permeability measurement of tight rocks. Four methods for estimating permeability from MICP data are found to have small bias and reasonable precision over a wide range of permeability: the modified Purcell, the Katz-Thompson Lc, Katz-Thompson Lh, and the Swanson methods. A weighted average of these permeability estimates corrects for accuracy problems and increases permeability estimate precision. However, this MICP-predicted average permeability still varies from measured Klinkenberg-corrected steady permeability by an average of a factor of 2. This mismatch may be more apparent than real. Restoring reservoir stress prior to conventional permeability measurement fails to remove completely the core damage caused by microfractures created during extraction, preparation, and storage of tight rock samples from deep boreholes. MICP permeabilities are estimated from the pore-throat distributions, which do not include the significant flow contributions from microfractures. Difference between MICP permeability estimates and measured permeability of tight samples may be caused by the inability of conventional permeability analysis to remove damage effects by stress restoration. If so, MICP permeability estimates are as good as or better than permeability measured from tight, subsurface samples. MICP permeability is either the ambient matrix permeability or a stressed matrix permeability, depending on the relative magnitude of in situ reservoir stress and Hg pressure at threshold saturation. Laminar flow theory predicts a strong correlation between permeability and pore-throat distribution as revealed by Mercury Injection Capillary Pressure (MICP) data. Previous studies have developed relationships between MICP data and permeability; however, the permeabilities predicted by different methods can differ substantially from the measured permeabilities and from each other, especially in low permeability samples of interest for unconventional reservoirs. The purposes of this study are to evaluate why there is such large scatter, identify algorithms that best predict permeability over a wide range of permeabilities, and evaluate what type of permeability is actually measured by MICP data. Precision of permeability predictions is low due to insufficient MICP pressure measurements, assumption of MICP curve shape, permeability anisotropy of geological samples, and low precision and accuracy of permeability measurement of tight rocks. Four methods for estimating permeability from MICP data are found to have small bias and reasonable precision over a wide range of permeability: the modified Purcell, the Katz-Thompson Lc, Katz-Thompson Lh, and the Swanson methods. A weighted average of these permeability estimates corrects for accuracy problems and increases permeability estimate precision. However, this MICP-predicted average permeability still varies from measured Klinkenberg-corrected steady permeability by an average of a factor of 2. This mismatch may be more apparent than real. Restoring reservoir stress prior to conventional permeability measurement fails to remove completely the core damage caused by microfractures created during extraction, preparation, and storage of tight rock samples from deep boreholes. MICP permeabilities are estimated from the pore-throat distributions, which do not include the significant flow contributions from microfractures. Difference between MICP permeability estimates and measured permeability of tight samples may be caused by the inability of conventional permeability analysis to remove damage effects by stress restoration. If so, MICP permeability estimates are as good as or better than permeability measured from tight, subsurface samples. MICP permeability is either the ambient matrix permeability or a stressed matrix permeability, depending on the relative magnitude of in situ reservoir stress and Hg pressure at threshold saturation. Panel_14931 Panel_14931 8:30 AM 5:00 PM

Unconventionals, perhaps more than other plays, demand consideration of process interactions. Geomechanical interactions occupy a central role in Unconventionals: geohistory, and the mechanical processes that operate, creates pre-cursor conditions; manufacturing the reservoir is a dominantly mechanical activity; and during reservoir production, mechanical interactions play a governing role. Classical methods of geomechanical interpretation and analysis fail to address the physics interactions, and can lead to incorrect deductions and decisions. These difficulties arise because the classical approaches assume that rock stress is an independent parameter and can be assigned a value. That view is physically impossible. The key point is that the concept of stress can be expressed in multiple ways –the most important one is that stress is the specific (mass/volume-related) elastic energy. Using this “take” on stress, we examine some important aspects of Unconventional reservoirs, focusing on hydrofracture stimulation. We assess some notions that inhibit understanding and interfere with the discovery of better practices. The hydrofracture process involves injecting a medium (usually water-based) into perforations, aiming to create new openings in the rock mass that will allow better hydrocarbon flow. The injected fluid pressure (an energy measure) and volume define the energy input. Some energy is consumed in making new discontinuities, and in shifting rocks. Where is the rest? As discontinuities open, the adjacent rocks become strained, typically in ways that lead to local contractions and volume loss, so their stress (elastic energy) state increases. In poro-elastic terms, the pre-existing pore fluids gain some of this added energy, so have higher pressures. Calculations show that injected fluids do not invade the pore system of the matrix rocks, and therefore, those not yet recovered in flowback must be located in newly-created (or enhanced) openings – typically fracture-like features. After one hydraulic fracture stage, the subsurface state is considerably altered, with impacts on subsequent stages. After multiple stages, the state is characterised by high energy levels that work against the maintenance of the permeability created by the stimulation activities. The full-physics interactions, expressed in terms of energy components and partitioning, lead to new insights, and provide a framework within which new operational practices can be contemplated. Unconventionals, perhaps more than other plays, demand consideration of process interactions. Geomechanical interactions occupy a central role in Unconventionals: geohistory, and the mechanical processes that operate, creates pre-cursor conditions; manufacturing the reservoir is a dominantly mechanical activity; and during reservoir production, mechanical interactions play a governing role. Classical methods of geomechanical interpretation and analysis fail to address the physics interactions, and can lead to incorrect deductions and decisions. These difficulties arise because the classical approaches assume that rock stress is an independent parameter and can be assigned a value. That view is physically impossible. The key point is that the concept of stress can be expressed in multiple ways –the most important one is that stress is the specific (mass/volume-related) elastic energy. Using this “take” on stress, we examine some important aspects of Unconventional reservoirs, focusing on hydrofracture stimulation. We assess some notions that inhibit understanding and interfere with the discovery of better practices. The hydrofracture process involves injecting a medium (usually water-based) into perforations, aiming to create new openings in the rock mass that will allow better hydrocarbon flow. The injected fluid pressure (an energy measure) and volume define the energy input. Some energy is consumed in making new discontinuities, and in shifting rocks. Where is the rest? As discontinuities open, the adjacent rocks become strained, typically in ways that lead to local contractions and volume loss, so their stress (elastic energy) state increases. In poro-elastic terms, the pre-existing pore fluids gain some of this added energy, so have higher pressures. Calculations show that injected fluids do not invade the pore system of the matrix rocks, and therefore, those not yet recovered in flowback must be located in newly-created (or enhanced) openings – typically fracture-like features. After one hydraulic fracture stage, the subsurface state is considerably altered, with impacts on subsequent stages. After multiple stages, the state is characterised by high energy levels that work against the maintenance of the permeability created by the stimulation activities. The full-physics interactions, expressed in terms of energy components and partitioning, lead to new insights, and provide a framework within which new operational practices can be contemplated. Panel_14926 Panel_14926 8:30 AM 5:00 PM

Panel_14450 Panel_14450 8:30 AM 5:00 PM

In this study we evaluate the vertical and along-strike variability of the thin-bedded distal delta-front and prodelta facies of the Upper Cretaceous Ferron Notom Delta Complex in Central Utah. Processes that potentially form thin beds include ignitive turbidity currents, hyperpycnal flows, and storm surges. After evaluation of sedimentary features of individual event beds in measured sections, the relative proportion of beds generated by these depositional processes/events has been calculated within a single parasequence (P6), which is continuously exposed along depositional strike. For each measured section, sedimentological data including grain size, lithology, bedding thickness, sedimentary structures, and ichnological suites have been documented. Fourteen different facies, and eight different facies associations were identified among 12 measured sections in this study. Overall fining-upward facies successions that show partial Bouma sequences are interpreted as due to ignitive turbidity currents. Facies successions showing either inverse-to-normal grading patterns or variations of sedimentary structures indicative of waxing and waning flow conditions are considered characteristic of deposition from hyperpycnal flows. Small silty to sandy wave ripple laminations or hummocky cross stratification (HCS) overlying erosional surfaces and capped by bioturbated mudstones are interpreted as the product of storm surges. Facies successions that show mixed influence from both fluvial- and storm-dominated depositional processes probably indicate deposition from storm-influenced ignitive turbidity currents or storm-influenced hyperpycnal flows. By combining the relative amount of sedimentary structures generated from different depositional processes, and small-scale features of the fine-grained facies within each section, the lateral variation of parasequence 6 can be illustrated. Parasequence 6 shows a strong along-strike variation with a completely wave-influenced environment in the north, passing abruptly into a fluvial-dominated area, then to an environment with varying degrees of fluvial and wave influence southward, and back to a wave-dominated environment further to the southeast. The depositional model of parasequence 6 is therefore interpreted as a storm-dominated symmetric delta with a large bayhead system. In this study we evaluate the vertical and along-strike variability of the thin-bedded distal delta-front and prodelta facies of the Upper Cretaceous Ferron Notom Delta Complex in Central Utah. Processes that potentially form thin beds include ignitive turbidity currents, hyperpycnal flows, and storm surges. After evaluation of sedimentary features of individual event beds in measured sections, the relative proportion of beds generated by these depositional processes/events has been calculated within a single parasequence (P6), which is continuously exposed along depositional strike. For each measured section, sedimentological data including grain size, lithology, bedding thickness, sedimentary structures, and ichnological suites have been documented. Fourteen different facies, and eight different facies associations were identified among 12 measured sections in this study. Overall fining-upward facies successions that show partial Bouma sequences are interpreted as due to ignitive turbidity currents. Facies successions showing either inverse-to-normal grading patterns or variations of sedimentary structures indicative of waxing and waning flow conditions are considered characteristic of deposition from hyperpycnal flows. Small silty to sandy wave ripple laminations or hummocky cross stratification (HCS) overlying erosional surfaces and capped by bioturbated mudstones are interpreted as the product of storm surges. Facies successions that show mixed influence from both fluvial- and storm-dominated depositional processes probably indicate deposition from storm-influenced ignitive turbidity currents or storm-influenced hyperpycnal flows. By combining the relative amount of sedimentary structures generated from different depositional processes, and small-scale features of the fine-grained facies within each section, the lateral variation of parasequence 6 can be illustrated. Parasequence 6 shows a strong along-strike variation with a completely wave-influenced environment in the north, passing abruptly into a fluvial-dominated area, then to an environment with varying degrees of fluvial and wave influence southward, and back to a wave-dominated environment further to the southeast. The depositional model of parasequence 6 is therefore interpreted as a storm-dominated symmetric delta with a large bayhead system. Panel_15147 Panel_15147 8:30 AM 5:00 PM

The type locality of the Loyd Sandstone member of the Buck Tongue of the Mancos Shale (Loyd) is located 100 km northeast of Rangely, CO near Hamilton. Subsurface correlations indicate that Loyd-equivalent strata are exposed in outcrops near Rangely. We describe the facies, ichnology, and architecture of the Loyd near Rangley and compare-contrast these with previously identified Cretaceous river-dominated deltas of the Panther Tongue and Ferron Sandstone. This approach reveals that abundant foresets built by traction-dominated underflows (hyperpycnal flows) indicate that the Loyd delta should be classified as river-dominated. An argument can be made; however, that a high abundance and high diversity trace fossil assemblage, deeply penetrating burrows, and flaser-wavy-lenticular bedded mud between foresets is evidence that the delta front experienced recurring, extended periods of slow sedimentation and oxygen-rich marine water influx during which marine fauna flourished and tidal and wave forces dominated. North of Rangley, the Loyd thickens laterally from a sub-meter scale sand bed to a 20+ m-thick succession. The basal contact of the Loyd is gradational with the underlying Buck Tongue of the Mancos, displaying a classic upward-coarsening succession typical of deltas. Facies include: muddy-siltstones, low-angle planar laminated sandstones interbedded with flaser-wavy-lenticular bedded muds, and gradational to erosively-based trough cross-stratified sands. Interpreted depositional environments include prodelta, delta front, distributary mouth bars, and distributary channels. Low angle planar lamination in delta foresets is the dominant sedimentary structure and mirrors the sequences documented from the Ferron and Panther Tongue. Trough cross-stratified sands the top of the Loyd are interpreted as mouth bars and subaqueous to subaerial distributary channels. The trace fossil assemblage that includes Ophiomorpha, Thalassinoides, Planolites, Schaubcylindrichnus, Palaeophycus, Diplocraterion, Helminthopsis, and Bergaueria is uncharacteristically high in diversity for a delta that sedimentary structures and architectures indicate to be river-dominated. Although the Loyd has many characteristics typical of a river-dominated delta, care should be taken when assigning this classification. Closer inspection may reveal that much time is recorded by relative quiescence on the delta front, a characteristic not typically associated with river dominance. The type locality of the Loyd Sandstone member of the Buck Tongue of the Mancos Shale (Loyd) is located 100 km northeast of Rangely, CO near Hamilton. Subsurface correlations indicate that Loyd-equivalent strata are exposed in outcrops near Rangely. We describe the facies, ichnology, and architecture of the Loyd near Rangley and compare-contrast these with previously identified Cretaceous river-dominated deltas of the Panther Tongue and Ferron Sandstone. This approach reveals that abundant foresets built by traction-dominated underflows (hyperpycnal flows) indicate that the Loyd delta should be classified as river-dominated. An argument can be made; however, that a high abundance and high diversity trace fossil assemblage, deeply penetrating burrows, and flaser-wavy-lenticular bedded mud between foresets is evidence that the delta front experienced recurring, extended periods of slow sedimentation and oxygen-rich marine water influx during which marine fauna flourished and tidal and wave forces dominated. North of Rangley, the Loyd thickens laterally from a sub-meter scale sand bed to a 20+ m-thick succession. The basal contact of the Loyd is gradational with the underlying Buck Tongue of the Mancos, displaying a classic upward-coarsening succession typical of deltas. Facies include: muddy-siltstones, low-angle planar laminated sandstones interbedded with flaser-wavy-lenticular bedded muds, and gradational to erosively-based trough cross-stratified sands. Interpreted depositional environments include prodelta, delta front, distributary mouth bars, and distributary channels. Low angle planar lamination in delta foresets is the dominant sedimentary structure and mirrors the sequences documented from the Ferron and Panther Tongue. Trough cross-stratified sands the top of the Loyd are interpreted as mouth bars and subaqueous to subaerial distributary channels. The trace fossil assemblage that includes Ophiomorpha, Thalassinoides, Planolites, Schaubcylindrichnus, Palaeophycus, Diplocraterion, Helminthopsis, and Bergaueria is uncharacteristically high in diversity for a delta that sedimentary structures and architectures indicate to be river-dominated. Although the Loyd has many characteristics typical of a river-dominated delta, care should be taken when assigning this classification. Closer inspection may reveal that much time is recorded by relative quiescence on the delta front, a characteristic not typically associated with river dominance. Panel_15136 Panel_15136 8:30 AM 5:00 PM

Exceptional rates of subsidence (up to 3000 m/Ma) and sediment supply (from a tectonically-active hinterland) have preserved a >6 km stratigraphic record of Mio-Pliocene coastal-deltaic sedimentation in the Baram Delta Province (BDP) of NW Borneo. Equivalent present-day coastal systems (e.g. Baram, Trusan and Padas deltas) display substantial decadal-kyr morphological changes. Deconvolving allogenic vs. autogenic controls on the evolution of these systems will be illustrated in two contrasting late-mid Miocene outcrop successions in the BDP: (1) the Lambir Formation (western BDP), and (2) the Belait Formation (eastern BDP). The Lambir Formation records deposition during rapid early coastal-deltaic progradation and comprises fluvio-tidal sandstones that are sharp-to-erosionally juxtaposed on wave-dominated (storm-reworked) prodelta to delta front successions. Single and multi-storey channel bodies comprise: (i) sand-dominated bars and dunes (2-9 m thick); (ii) laterally migrating, elongate tidal bars (inclined heterolithic strata, 1-6 m thick); and (iii) mud-dominated carbonaceous hetereolithics (1-2 m thick). Abrupt vertical changes from sandier facies to bioturbated mudstones reflect rapid autogenic changes in local sediment supply and fluvial energy. Proximal parasequence sets also contain 4-17 m scale, erosive-based fluvial channel bodies and wave-tide influenced, muddy sandbar deposits, representing local flooding or wave ravinement during channel abandonment. The Belait Formation was deposited under significant tectonic influence within a narrow (5-20 km), fault-bounded embayment (Berakas Syncline). This sub-basin configuration and its high rate of accommodation creation formed an effective sediment trap, with high aggradation and a steeply rising shelf trajectory. Abundant upward coarsening successions are interpreted as prograding storm- and river flood-influenced delta front deposits. Storm-reworking of tidal bars and intercalated tidal sand bodies further indicate mixed-energy processes. However, larger-scale (10-100 m) partitioning of stratigraphic architecture into relatively tide- and wave-dominated successions suggests temporal changes in process dominance, in response to allogenic-forced changes in shoreline geometry. The different sedimentological and physical stratigraphic expressions of these two time-equivalent and geographically-adjacent coastal-deltaic successions will be discussed in relation to autogenic and allogenic processes. Exceptional rates of subsidence (up to 3000 m/Ma) and sediment supply (from a tectonically-active hinterland) have preserved a >6 km stratigraphic record of Mio-Pliocene coastal-deltaic sedimentation in the Baram Delta Province (BDP) of NW Borneo. Equivalent present-day coastal systems (e.g. Baram, Trusan and Padas deltas) display substantial decadal-kyr morphological changes. Deconvolving allogenic vs. autogenic controls on the evolution of these systems will be illustrated in two contrasting late-mid Miocene outcrop successions in the BDP: (1) the Lambir Formation (western BDP), and (2) the Belait Formation (eastern BDP). The Lambir Formation records deposition during rapid early coastal-deltaic progradation and comprises fluvio-tidal sandstones that are sharp-to-erosionally juxtaposed on wave-dominated (storm-reworked) prodelta to delta front successions. Single and multi-storey channel bodies comprise: (i) sand-dominated bars and dunes (2-9 m thick); (ii) laterally migrating, elongate tidal bars (inclined heterolithic strata, 1-6 m thick); and (iii) mud-dominated carbonaceous hetereolithics (1-2 m thick). Abrupt vertical changes from sandier facies to bioturbated mudstones reflect rapid autogenic changes in local sediment supply and fluvial energy. Proximal parasequence sets also contain 4-17 m scale, erosive-based fluvial channel bodies and wave-tide influenced, muddy sandbar deposits, representing local flooding or wave ravinement during channel abandonment. The Belait Formation was deposited under significant tectonic influence within a narrow (5-20 km), fault-bounded embayment (Berakas Syncline). This sub-basin configuration and its high rate of accommodation creation formed an effective sediment trap, with high aggradation and a steeply rising shelf trajectory. Abundant upward coarsening successions are interpreted as prograding storm- and river flood-influenced delta front deposits. Storm-reworking of tidal bars and intercalated tidal sand bodies further indicate mixed-energy processes. However, larger-scale (10-100 m) partitioning of stratigraphic architecture into relatively tide- and wave-dominated successions suggests temporal changes in process dominance, in response to allogenic-forced changes in shoreline geometry. The different sedimentological and physical stratigraphic expressions of these two time-equivalent and geographically-adjacent coastal-deltaic successions will be discussed in relation to autogenic and allogenic processes. Panel_15146 Panel_15146 8:30 AM 5:00 PM

Modeling the size, shape, and connectivity of deltaic stratal bodies has important implications for hydrocarbon reservoir assessment and prediction. Here, we present initial results from 12 depth-averaged simulations of river, tide, and wave-dominated deltaic systems in Delft3D. All runs were computed on a 24 x 16 km grid with 100 x 100 m cell size. For the offshore boundary conditions, we specified time-varying wave conditions, and/or constant semidiurnal tidal forcing. For the upstream boundary condition we specified a steady river discharge of 11,000 m3/s, carrying an initial sand to cohesive mud ratio of approximately 2:1. Analyses of runs consisted of extracting sand and mud body dimensions. Results show that river delta sand bodies are predominantly composed of elongate levees and mouth bars, which together create digitate deposits with long axes parallel to local flow. Fluvial sand bodies have limited connectivity due to intervening interdistributary muds. Tide-dominated delta sand bodies are composed of two types: near fluvial channels there are elongate levee and crescentic mouth bar sands, while in interdistributary bays tidal flats develop with shore-perpendicular sandy tidal shoals. As a result, tide-dominated deltas tend to have high sand connectivity along the delta perimeter. On the contrary, in the delta interior where river influence is low, connectivity is low due to local accumulation of mud that caps and separates sandy tidal shoals. Early in the development of wave dominated deltas, sand bodies are similar to those of river-dominated deltas. However, as deltas prograde into deeper water where wave influence is higher, levees and mouth bars are replaced by spits and sand ridges. In areas downdrift of alongshore transport, sand body connectivity is low due to the presence of sandy spits with intervening mud deposits. Initial analysis suggests that small-scale gyres trap mud leading to enhanced deposition in these regions. At the delta front, sediment distribution by longshore transport leads to the formation of laterally continuous sand ridges forming sheet-like sand bodies. Additional experiments show that basin bathymetry is a major control on stratal body dimensions. For example, for the same tidal amplitude, tidal strength is amplified in shallower basins compared to deeper basins. Conversely, for the same wave height, wave strength is amplified in deeper basins relative to shallower basins. Modeling the size, shape, and connectivity of deltaic stratal bodies has important implications for hydrocarbon reservoir assessment and prediction. Here, we present initial results from 12 depth-averaged simulations of river, tide, and wave-dominated deltaic systems in Delft3D. All runs were computed on a 24 x 16 km grid with 100 x 100 m cell size. For the offshore boundary conditions, we specified time-varying wave conditions, and/or constant semidiurnal tidal forcing. For the upstream boundary condition we specified a steady river discharge of 11,000 m3/s, carrying an initial sand to cohesive mud ratio of approximately 2:1. Analyses of runs consisted of extracting sand and mud body dimensions. Results show that river delta sand bodies are predominantly composed of elongate levees and mouth bars, which together create digitate deposits with long axes parallel to local flow. Fluvial sand bodies have limited connectivity due to intervening interdistributary muds. Tide-dominated delta sand bodies are composed of two types: near fluvial channels there are elongate levee and crescentic mouth bar sands, while in interdistributary bays tidal flats develop with shore-perpendicular sandy tidal shoals. As a result, tide-dominated deltas tend to have high sand connectivity along the delta perimeter. On the contrary, in the delta interior where river influence is low, connectivity is low due to local accumulation of mud that caps and separates sandy tidal shoals. Early in the development of wave dominated deltas, sand bodies are similar to those of river-dominated deltas. However, as deltas prograde into deeper water where wave influence is higher, levees and mouth bars are replaced by spits and sand ridges. In areas downdrift of alongshore transport, sand body connectivity is low due to the presence of sandy spits with intervening mud deposits. Initial analysis suggests that small-scale gyres trap mud leading to enhanced deposition in these regions. At the delta front, sediment distribution by longshore transport leads to the formation of laterally continuous sand ridges forming sheet-like sand bodies. Additional experiments show that basin bathymetry is a major control on stratal body dimensions. For example, for the same tidal amplitude, tidal strength is amplified in shallower basins compared to deeper basins. Conversely, for the same wave height, wave strength is amplified in deeper basins relative to shallower basins. Panel_15140 Panel_15140 8:30 AM 5:00 PM

Mouth bars develop where fluvial distributaries deliver coarse sediment to a shoreline. As a consequence, they are typically considered, by default, to be fluvial-dominated. Detailed studies of both modern and ancient shorelines show this to be an oversimplification. Mouth bars can have a complicated internal architecture strongly influenced by wave and/or tidal reworking and can, in fact, be wave- or tide-dominated. We show examples of end-member, wave- and tide-dominated mouth bars and compare these to the morphology of a classical fluvial-dominated mouth bar model. The examples show that the balance of fluvial, wave and tidal processes operating at the mouth bar location can result in highly contrasting mouth bar geometries, facies stacking patterns, preserved sedimentary structures and the internal architectures of baffles and barriers. Contrasting mouth bar growth patterns can also significantly affect the large-scale architecture of the system. We use geocellular modeling to illustrate the architecture of an ancient wave-dominated, tide-influenced mouth bar system from the Upper Cretaceous (Campanian) Horseshoe Canyon Formation, exposed near Drumheller, Canada. Near continuous outcrop exposure, in combination with four cored wells and seventy five wireline logs, allow detailed characterization of the mouth bar system in outcrop and subsurface. A hierarchy of depositional units are included in the modeling. At the largest scale is a Regressive Element Complex Assemblage Set (RECAS) up to 8 m thick. This consists of two wave-dominated, tide-influenced, fluvial-affected (Wtf) Mouth bar Element Complexes (EC). Each Wtf-Mouthbar EC can be subdivided into three to four Element Sets (ES), made up of multiple kilometre-scale mouth bar Element (E) lobes. Dipping, mud-draped clinoform surfaces are identified at two scales (bed- and bedset-scale), and tidal bundle sequences are recognized within clinoform bedsets. Geocellular models have been constructed at a scale sufficiently fine to enable the reconstruction of individual mouth bar lobes and intra-lobe baffles and barriers. A partial modern analogue from the Mitchell River Delta, Gulf of Carpentaria, Australia, is also used to help constrain planform geometries of the mouth bar sand-body and distributary channels. The resulting models can be used to assess the impact of intra-lobe architectures on reservoir connectivity and fluid flow characteristics. Mouth bars develop where fluvial distributaries deliver coarse sediment to a shoreline. As a consequence, they are typically considered, by default, to be fluvial-dominated. Detailed studies of both modern and ancient shorelines show this to be an oversimplification. Mouth bars can have a complicated internal architecture strongly influenced by wave and/or tidal reworking and can, in fact, be wave- or tide-dominated. We show examples of end-member, wave- and tide-dominated mouth bars and compare these to the morphology of a classical fluvial-dominated mouth bar model. The examples show that the balance of fluvial, wave and tidal processes operating at the mouth bar location can result in highly contrasting mouth bar geometries, facies stacking patterns, preserved sedimentary structures and the internal architectures of baffles and barriers. Contrasting mouth bar growth patterns can also significantly affect the large-scale architecture of the system. We use geocellular modeling to illustrate the architecture of an ancient wave-dominated, tide-influenced mouth bar system from the Upper Cretaceous (Campanian) Horseshoe Canyon Formation, exposed near Drumheller, Canada. Near continuous outcrop exposure, in combination with four cored wells and seventy five wireline logs, allow detailed characterization of the mouth bar system in outcrop and subsurface. A hierarchy of depositional units are included in the modeling. At the largest scale is a Regressive Element Complex Assemblage Set (RECAS) up to 8 m thick. This consists of two wave-dominated, tide-influenced, fluvial-affected (Wtf) Mouth bar Element Complexes (EC). Each Wtf-Mouthbar EC can be subdivided into three to four Element Sets (ES), made up of multiple kilometre-scale mouth bar Element (E) lobes. Dipping, mud-draped clinoform surfaces are identified at two scales (bed- and bedset-scale), and tidal bundle sequences are recognized within clinoform bedsets. Geocellular models have been constructed at a scale sufficiently fine to enable the reconstruction of individual mouth bar lobes and intra-lobe baffles and barriers. A partial modern analogue from the Mitchell River Delta, Gulf of Carpentaria, Australia, is also used to help constrain planform geometries of the mouth bar sand-body and distributary channels. The resulting models can be used to assess the impact of intra-lobe architectures on reservoir connectivity and fluid flow characteristics. Panel_15138 Panel_15138 8:30 AM 5:00 PM

Conventionally, the lower Middle Jurassic of the Brent Group in the northern North Sea, accumulating Rannoch, Etive and parts of Ness formations, has always been classed as a northward prograding delta system. Recently, it is shown to include thick (15-40 m) sandy deposits with tidal signatures, are also high quality reservoirs. Tidal signatures in these three formations are various but may be of similar origin and controlled by syn-depositional system. The Rannoch formation has generally been assumed as wave-dominated delta front that expressed by repeated HCS and SCS storm events. However, in this case, 20% of the total thickness of the cored part, consists of tidally influenced deposits as capping to storm-event beds. Evidence of tidal currents are manifested as tidal bundle, tidal rhythmites, double mud drapes and reactivation surface. The whole packages are dominated by alternation of storm-event beds and fair-weather tidal intervals. The overlain Etive formation is genetically-related with the Rannoch Formation, but there is a marked erosional surface suggesting the onset of transgression and causing development of small scale estuary in inter-deltaic lobe. Tidal signatures within Etive formation are manifested as fluid mud in distributary channels. The basal Ness formation is composed of nearly 40 m thick, marine sandstone units, showing compound cross-bedding, and Ophimorpha traces, they are likely to be stacked tidal bars composed of single or compound dunes. The overall upward-finning succession, suggests that the bars fill channels in an open-estuary setting that was transgressive. The clean nature, good sorting, and coarse grain size suggests that these estuarine tidal bars received sediment supply at the estuary mouth by strong tidal currents. Tidal signatures repeated in the lower Brent Group is regionally occurred and may be related to tectonic rifting, where tidal influence is amplified by reshaping of shoreline geometry causing by variations in the subsidence/uplift rate. Conventionally, the lower Middle Jurassic of the Brent Group in the northern North Sea, accumulating Rannoch, Etive and parts of Ness formations, has always been classed as a northward prograding delta system. Recently, it is shown to include thick (15-40 m) sandy deposits with tidal signatures, are also high quality reservoirs. Tidal signatures in these three formations are various but may be of similar origin and controlled by syn-depositional system. The Rannoch formation has generally been assumed as wave-dominated delta front that expressed by repeated HCS and SCS storm events. However, in this case, 20% of the total thickness of the cored part, consists of tidally influenced deposits as capping to storm-event beds. Evidence of tidal currents are manifested as tidal bundle, tidal rhythmites, double mud drapes and reactivation surface. The whole packages are dominated by alternation of storm-event beds and fair-weather tidal intervals. The overlain Etive formation is genetically-related with the Rannoch Formation, but there is a marked erosional surface suggesting the onset of transgression and causing development of small scale estuary in inter-deltaic lobe. Tidal signatures within Etive formation are manifested as fluid mud in distributary channels. The basal Ness formation is composed of nearly 40 m thick, marine sandstone units, showing compound cross-bedding, and Ophimorpha traces, they are likely to be stacked tidal bars composed of single or compound dunes. The overall upward-finning succession, suggests that the bars fill channels in an open-estuary setting that was transgressive. The clean nature, good sorting, and coarse grain size suggests that these estuarine tidal bars received sediment supply at the estuary mouth by strong tidal currents. Tidal signatures repeated in the lower Brent Group is regionally occurred and may be related to tectonic rifting, where tidal influence is amplified by reshaping of shoreline geometry causing by variations in the subsidence/uplift rate. Panel_15143 Panel_15143 8:30 AM 5:00 PM

The Mitchell River megafan comprises a distributive network of modern and palaeo-distributary channel belts. This monsoonal catchment supplies sediment to a mixed-process marginal marine system within the low accommodation Gulf of Carpentaria. Detailed mapping, sonic coring, trenching and topographic surveying have been used to characterise the palaeo-distributary channel belts; the bathymetry and bottom composition of their modern counterparts on the lower delta plain have also been surveyed. These data have revealed systematic downstream and lateral changes in palaeo-channel belt architecture, with implications for similar subsurface reservoirs. The deepest channel belts occur proximal to the apex of the fan and are characterised by coarse fills. Their planform geometries are generally straight and single thread. Laterised alluvium has restricted their lateral migration and promoted aggradation and avulsion on the fan. These channel belts transition into laterally accreted scrolled systems on the lower fan, which are shallower and are comprised of finer grained material. The highest concentration of avulsion nodes occurs in this downstream zone, which coincides with the landward limit of the backwater effect. These channel belts are not directly influenced by tidal currents. Further downstream, channel belts on the delta plain have been influenced by tidal currents and are classified along the continuum of fluvial- dominated, tide-influenced (Ft), to tide-dominated fluvial-influenced (Tf), to tide dominated (T). The majority of active channels that comprise these belts show a landward tapering, “funnel shaped” morphology. Ft channels are sinuous and are characterised tidally influenced inclined heterolithic stratification (IHS) overlying fluvial sand, and drawdown effects near their mouths determine that their channel depths typically reduce upstream. In contrast, Tf fills are composed of a higher proportion of mud than Ft channels, and often exhibit a straight-meandering-straight pattern, typical of estuaries. T channels are almost entirely mud filled. This continuum of channel types is also observed laterally within channel belts on the delta, as upstream avulsions cause channel belts to become progressively abandoned and influenced by changing combinations of processes. The geometry and composition of the channel fills are thus intimately linked to the palaeogeographic evolution of entire distributive system and are the subject of ongoing research. The Mitchell River megafan comprises a distributive network of modern and palaeo-distributary channel belts. This monsoonal catchment supplies sediment to a mixed-process marginal marine system within the low accommodation Gulf of Carpentaria. Detailed mapping, sonic coring, trenching and topographic surveying have been used to characterise the palaeo-distributary channel belts; the bathymetry and bottom composition of their modern counterparts on the lower delta plain have also been surveyed. These data have revealed systematic downstream and lateral changes in palaeo-channel belt architecture, with implications for similar subsurface reservoirs. The deepest channel belts occur proximal to the apex of the fan and are characterised by coarse fills. Their planform geometries are generally straight and single thread. Laterised alluvium has restricted their lateral migration and promoted aggradation and avulsion on the fan. These channel belts transition into laterally accreted scrolled systems on the lower fan, which are shallower and are comprised of finer grained material. The highest concentration of avulsion nodes occurs in this downstream zone, which coincides with the landward limit of the backwater effect. These channel belts are not directly influenced by tidal currents. Further downstream, channel belts on the delta plain have been influenced by tidal currents and are classified along the continuum of fluvial- dominated, tide-influenced (Ft), to tide-dominated fluvial-influenced (Tf), to tide dominated (T). The majority of active channels that comprise these belts show a landward tapering, “funnel shaped” morphology. Ft channels are sinuous and are characterised tidally influenced inclined heterolithic stratification (IHS) overlying fluvial sand, and drawdown effects near their mouths determine that their channel depths typically reduce upstream. In contrast, Tf fills are composed of a higher proportion of mud than Ft channels, and often exhibit a straight-meandering-straight pattern, typical of estuaries. T channels are almost entirely mud filled. This continuum of channel types is also observed laterally within channel belts on the delta, as upstream avulsions cause channel belts to become progressively abandoned and influenced by changing combinations of processes. The geometry and composition of the channel fills are thus intimately linked to the palaeogeographic evolution of entire distributive system and are the subject of ongoing research. Panel_15141 Panel_15141 8:30 AM 5:00 PM

Shelf accommodation has been emphasized as a major control on progradation of shelf margin systems and delivery of sand to deep water. However, a complicated interplay of factors including rate of sediment supply, shelf physiography, and lateral variability in dominant process regime challenge simple predictive models for slope sediment bypass and the development of basin-floor fans. Three-dimensional datasets can help to deconvolve these factors, but need to be regional in scale to capture basin margin architecture, with detailed facies observations to capture process regimes and the distribution of depositional environments. Here, the evolution of a shelf margin in the Permian Karoo basin, South Africa is investigated. More than 1000 regionally distributed sedimentary logs along a >150 km strike section, from shelf to basin-floor in both the Tanqua and Laingsburg depocentres provide data for stratigraphic panels that show the position of the clinoform rollover and the base-of slope through time. This helps to constrain water depth estimates, and to capture changes in slope length and gradient. This dataset has also been integrated with absolute age control and isopach mapping. A differential subsidence across the basin led to a thinner and progradational ramp type setting in the Tanqua depocentre, whereas a thicker slope succession in the Laingsburg depocentre features an aggradation followed by progadational stacking pattern. Late stage shelf margin progradation in the Laingsburg area operated by the accretion of silt through multiple parasequence cycles without the sandy part of each clinothem reaching the clinoform rollover. The downdip correlation of the Laingsburg deltas show that their associated slope deposits are generally less sand-rich than the underlying basin-floor stratigraphy of the Fort Brown Formation, which points to either physiographic change in the basin margin architecture and/or process regime through time. Detailed field observations have provided criteria to define a muddy shelf to slope transition. These findings provide a facies basis for equivalent seismic expressions in cases of margin progradation via fine grained material. These investigations have demonstrated that basin margin progradation can occur without development of basin-floor fans, and address the processes responsible for transporting fine grained material across the shelf and beyond the shelf edge rollover during relative sea-level highstands. Shelf accommodation has been emphasized as a major control on progradation of shelf margin systems and delivery of sand to deep water. However, a complicated interplay of factors including rate of sediment supply, shelf physiography, and lateral variability in dominant process regime challenge simple predictive models for slope sediment bypass and the development of basin-floor fans. Three-dimensional datasets can help to deconvolve these factors, but need to be regional in scale to capture basin margin architecture, with detailed facies observations to capture process regimes and the distribution of depositional environments. Here, the evolution of a shelf margin in the Permian Karoo basin, South Africa is investigated. More than 1000 regionally distributed sedimentary logs along a >150 km strike section, from shelf to basin-floor in both the Tanqua and Laingsburg depocentres provide data for stratigraphic panels that show the position of the clinoform rollover and the base-of slope through time. This helps to constrain water depth estimates, and to capture changes in slope length and gradient. This dataset has also been integrated with absolute age control and isopach mapping. A differential subsidence across the basin led to a thinner and progradational ramp type setting in the Tanqua depocentre, whereas a thicker slope succession in the Laingsburg depocentre features an aggradation followed by progadational stacking pattern. Late stage shelf margin progradation in the Laingsburg area operated by the accretion of silt through multiple parasequence cycles without the sandy part of each clinothem reaching the clinoform rollover. The downdip correlation of the Laingsburg deltas show that their associated slope deposits are generally less sand-rich than the underlying basin-floor stratigraphy of the Fort Brown Formation, which points to either physiographic change in the basin margin architecture and/or process regime through time. Detailed field observations have provided criteria to define a muddy shelf to slope transition. These findings provide a facies basis for equivalent seismic expressions in cases of margin progradation via fine grained material. These investigations have demonstrated that basin margin progradation can occur without development of basin-floor fans, and address the processes responsible for transporting fine grained material across the shelf and beyond the shelf edge rollover during relative sea-level highstands. Panel_15142 Panel_15142 8:30 AM 5:00 PM

Early sequence stratigraphic models applied to shallow-marine successions revolutionized methods of reservoir prediction and characterization. In the decades following introduction of these methods, there have been fundamental improvements in our understanding of depositional process controls on reservoir architecture and internal facies variations defined within a sequence-stratigraphic context. Such improvements reflect not just a better understanding of how changes in dominant depositional processes control facies patterns, but also recognition of process changes and differential preservation as areas along the shoreline are locally abandoned by river avulsion and reworked by shoreline and shelf processes during larger-scale shifts in the position of deposition. A classification of shallow-marine stratigraphic successions is presented based on: 1) dominant depositional process (river, wave, tide), 2) shoreline trajectory, and 3) relative preservation of regressive deposits following transgression (related to accommodation/sediment-supply ratios). Although all shallow-marine deposits reflect variable interaction of river and marine processes, and there is a gradation between extremes of shoreline trajectory, we define specific reservoir complex types: 1) to highlight reservoir-element variations within a range of systems, 2) as a framework for the organization of outcrop and subsurface analog examples, 3) to provide a structure for development of a reservoir-element dimensional database, and 4) to guide stratigraphic correlation-framework definition. Thirteen shallow-marine complex types are shown relative to their position within a regressive–transgressive clastic wedge formed during deposition of either a higher or lower long-term accommodation-growth sequence. Although such classification involves simplification and generalization, our goal is to broadly define classes that span the full range of shallow-marine reservoir systems, and to highlight contrasts in stratigraphic correlation styles and facies trends that need to be considered to characterize reservoirs within diverse types of shallow-marine deposits. A catalog of examples is presented to show each complex type, key stratigraphic surfaces, and stratigraphic position within longer-term regional sequences. General correlation concepts important for prediction of facies variations within each class are highlighted by presenting outcrop and subsurface examples. Early sequence stratigraphic models applied to shallow-marine successions revolutionized methods of reservoir prediction and characterization. In the decades following introduction of these methods, there have been fundamental improvements in our understanding of depositional process controls on reservoir architecture and internal facies variations defined within a sequence-stratigraphic context. Such improvements reflect not just a better understanding of how changes in dominant depositional processes control facies patterns, but also recognition of process changes and differential preservation as areas along the shoreline are locally abandoned by river avulsion and reworked by shoreline and shelf processes during larger-scale shifts in the position of deposition. A classification of shallow-marine stratigraphic successions is presented based on: 1) dominant depositional process (river, wave, tide), 2) shoreline trajectory, and 3) relative preservation of regressive deposits following transgression (related to accommodation/sediment-supply ratios). Although all shallow-marine deposits reflect variable interaction of river and marine processes, and there is a gradation between extremes of shoreline trajectory, we define specific reservoir complex types: 1) to highlight reservoir-element variations within a range of systems, 2) as a framework for the organization of outcrop and subsurface analog examples, 3) to provide a structure for development of a reservoir-element dimensional database, and 4) to guide stratigraphic correlation-framework definition. Thirteen shallow-marine complex types are shown relative to their position within a regressive–transgressive clastic wedge formed during deposition of either a higher or lower long-term accommodation-growth sequence. Although such classification involves simplification and generalization, our goal is to broadly define classes that span the full range of shallow-marine reservoir systems, and to highlight contrasts in stratigraphic correlation styles and facies trends that need to be considered to characterize reservoirs within diverse types of shallow-marine deposits. A catalog of examples is presented to show each complex type, key stratigraphic surfaces, and stratigraphic position within longer-term regional sequences. General correlation concepts important for prediction of facies variations within each class are highlighted by presenting outcrop and subsurface examples. Panel_15144 Panel_15144 8:30 AM 5:00 PM

Ancient river-dominated deltas host significant accumulations of hydrocarbons. The influence of wave energy is common, and adds architectural complexity to the stratigraphic record. While facies models for wave-influenced deltas exist, they are under-represented among the suite of deltaic outcrop analogs. The Campanian Upper Sego Member of the Iles Formation is composed of prograding deltaic parasequences. This study focuses on one parasequence, located around Hunter Canyon, Colorado, that is exceptionally well exposed in three dimensions and contains evidence of mixed fluvial and wave influence. During deposition the parasequence evolved from a fluvial-dominated delta, then to a wave-dominated delta, and finally back to a fluvial-dominated delta. This study documents the imprint of these process regimes on stratigraphic architecture. Data collected in this study include high-resolution interpreted photo panels, detailed measured sections at decimeter resolution, and paleocurrent data to document the 3D stratigraphic architecture and facies distribution of one delta lobe. Fluvial dominated components of the delta contain distributary channels, clinoforming mouth bars, and significant bottomset (i.e. prodelta mudstone) aggradation. In contrast, wave dominated components are erosional into underlying strata, composed primarily of swaley cross stratification, have relatively low-angle foresets, and contain a large proportion of soft-sediment deformational features. Ancient river-dominated deltas host significant accumulations of hydrocarbons. The influence of wave energy is common, and adds architectural complexity to the stratigraphic record. While facies models for wave-influenced deltas exist, they are under-represented among the suite of deltaic outcrop analogs. The Campanian Upper Sego Member of the Iles Formation is composed of prograding deltaic parasequences. This study focuses on one parasequence, located around Hunter Canyon, Colorado, that is exceptionally well exposed in three dimensions and contains evidence of mixed fluvial and wave influence. During deposition the parasequence evolved from a fluvial-dominated delta, then to a wave-dominated delta, and finally back to a fluvial-dominated delta. This study documents the imprint of these process regimes on stratigraphic architecture. Data collected in this study include high-resolution interpreted photo panels, detailed measured sections at decimeter resolution, and paleocurrent data to document the 3D stratigraphic architecture and facies distribution of one delta lobe. Fluvial dominated components of the delta contain distributary channels, clinoforming mouth bars, and significant bottomset (i.e. prodelta mudstone) aggradation. In contrast, wave dominated components are erosional into underlying strata, composed primarily of swaley cross stratification, have relatively low-angle foresets, and contain a large proportion of soft-sediment deformational features. Panel_15137 Panel_15137 8:30 AM 5:00 PM

Four cores and 14 image logs from the Strawn Formation in the Kinder Morgan Katz Field Unit and adjacent Orsborne Field were logged with particular attention given to identifying lithofacies. Direct comparisons between physical core and image logs were used to produce a borehole image lithofacies catalog for the Katz Field Unit (lithofacies A through L). Combined lithofacies identified in core and image logs include: A) mudstone to bioturbated mudstone; B) parallel laminated to bioturbated sandstone to shaley sandstone; C) flaser- to lenticular- to wavy-bedded sandstone and mudstone; D) heavily bioturbated sandstone; E) ripple-laminated to trough cross-stratified sandstone; F) ripple-laminated to herringbone cross-stratified sandstone; G) cross-bedded sandstone; H) interbedded sandstone and limestone; I) wavy- to parallel-bedded limestone; J) cross-bedded limestone; K) diagenetic-nodular and/or brecciated limestone; and L) interbedded limestone and shale. Accessories commonly associated with lithofacies in both core and Formation Micro-Imager (FMI) include: bioturbation, carbonate bioclasts, carbonate breccias, carbonate cement, plant debris, siderite nodules, slumps and contorted bedding, microfaults, mud balls, and mud rip-up clasts. Core and image log lithofacies associated with a combination of Skolithos, Cruziana, mixed Skolithos-Cruziana, and rare Zoophycus ichnofacies identified in the cores suggest that paleoenvironments of the Katz Field include a bayhead delta, back-barrier estuary-embayment, flood tidal delta, tidal flat, and upper to middle shoreface. Trace fossils include Asterosoma, Diplocraterion, Chondrites, Conichnus, Cosmorhaphe, Cylindrichnus, Helminthopsis, Phycosiphon, Rhizocorallium, Rosellia, Skolithos, Teichichnus, and Zoophycus. Conodonts collected from crinoid-bryozoan-brachiopod wackestone-packstones in two cores include age-diagnostic species (Neognathodus expansus and Gondolella pohi, Idiognathodus aff. I delicates) indicate a mid Desmoinesian age. The integration and interpretation of the Katz Field Unit core data, image log lithofacies, and ichnofacies help to guide the propagation of lithofacies to a larger area within the unit leading to a clearer understanding of the distribution of flow units between wells, both horizontally and vertically at depth. This assists in correlation of lithofacies geometries, supporting our current conceptual reservoir model and identification of pay zones and flow barriers. Four cores and 14 image logs from the Strawn Formation in the Kinder Morgan Katz Field Unit and adjacent Orsborne Field were logged with particular attention given to identifying lithofacies. Direct comparisons between physical core and image logs were used to produce a borehole image lithofacies catalog for the Katz Field Unit (lithofacies A through L). Combined lithofacies identified in core and image logs include: A) mudstone to bioturbated mudstone; B) parallel laminated to bioturbated sandstone to shaley sandstone; C) flaser- to lenticular- to wavy-bedded sandstone and mudstone; D) heavily bioturbated sandstone; E) ripple-laminated to trough cross-stratified sandstone; F) ripple-laminated to herringbone cross-stratified sandstone; G) cross-bedded sandstone; H) interbedded sandstone and limestone; I) wavy- to parallel-bedded limestone; J) cross-bedded limestone; K) diagenetic-nodular and/or brecciated limestone; and L) interbedded limestone and shale. Accessories commonly associated with lithofacies in both core and Formation Micro-Imager (FMI) include: bioturbation, carbonate bioclasts, carbonate breccias, carbonate cement, plant debris, siderite nodules, slumps and contorted bedding, microfaults, mud balls, and mud rip-up clasts. Core and image log lithofacies associated with a combination of Skolithos, Cruziana, mixed Skolithos-Cruziana, and rare Zoophycus ichnofacies identified in the cores suggest that paleoenvironments of the Katz Field include a bayhead delta, back-barrier estuary-embayment, flood tidal delta, tidal flat, and upper to middle shoreface. Trace fossils include Asterosoma, Diplocraterion, Chondrites, Conichnus, Cosmorhaphe, Cylindrichnus, Helminthopsis, Phycosiphon, Rhizocorallium, Rosellia, Skolithos, Teichichnus, and Zoophycus. Conodonts collected from crinoid-bryozoan-brachiopod wackestone-packstones in two cores include age-diagnostic species (Neognathodus expansus and Gondolella pohi, Idiognathodus aff. I delicates) indicate a mid Desmoinesian age. The integration and interpretation of the Katz Field Unit core data, image log lithofacies, and ichnofacies help to guide the propagation of lithofacies to a larger area within the unit leading to a clearer understanding of the distribution of flow units between wells, both horizontally and vertically at depth. This assists in correlation of lithofacies geometries, supporting our current conceptual reservoir model and identification of pay zones and flow barriers. Panel_15145 Panel_15145 8:30 AM 5:00 PM

Panel_14451 Panel_14451 8:30 AM 5:00 PM

The Cambrian Mount Clark Formation is potential reservoir-quality sandstone within the Central Mackenzie Valley of the Northwest Territories, Canada. The succession lies unconformably over Proterozoic rocks and represents a shoreface to offshore setting, and it is flanked by paleotopographic highs to the West (Mackenzie Arch) and East (Mahony Arch). The Mount Clark Formation has been the subject of several regional studies, but detailed ichnological and sedimentological investigations have not been conducted. Depositional affinities are poorly understood with fluvial to shallow marine environments proposed within existing lithostratigraphic schemes. To produce a detailed sedimentological framework, four outcrops within the Mackenzie Mountains were measured and described to identify characteristic ichnological assemblages and sedimentological fabrics. In general, the Mount Clark Formation is represented by a regressive parasequence set. Base-level changes are expressed at parasequence boundaries, these are demarcated by sharp erosional contacts separating highly bioturbated lower shoreface strata from hummocky and trough cross-stratified middle to upper shoreface strata, and the presence of a localized Glossifungites-demarcated omission assemblage. Observed trace fossils include Skolithos, Palaeophycus Striatus, Diplocraterion, Asterosoma, Planolites, Phoebichnus, Rosselia?, Rhizocorallium?, Teichichnus, Phycodes, and Chondrites. Depending on the proximity of the studied locales to the paleo-shoreline, trace fossils tend to represent the distal Skolithos Ichnofacies in proximal settings and the archetypal Cruziana Ichnofacies in more distal positions. Bioturbation intensity and ichnological diversity tends to increase towards the offshore. Importantly tempestite beds, indicating a storm-influenced depositional setting, are observed. Unlike well-studied Mesozoic tempestites, these exhibit poorly developed to non-existent post-storm tempestite colonization trace fossil suites. Our observations firmly place the studied sections of the Mount Clark Formation in the shallow marine (offshore to shoreface) realm. Characteristically, the unit appears to have deposited during a late highstand systems tract, where accommodation was low, thus leading to the progradation and amalgamation of these units. Future work is aimed at refining the depositional and stratigraphic framework. The Cambrian Mount Clark Formation is potential reservoir-quality sandstone within the Central Mackenzie Valley of the Northwest Territories, Canada. The succession lies unconformably over Proterozoic rocks and represents a shoreface to offshore setting, and it is flanked by paleotopographic highs to the West (Mackenzie Arch) and East (Mahony Arch). The Mount Clark Formation has been the subject of several regional studies, but detailed ichnological and sedimentological investigations have not been conducted. Depositional affinities are poorly understood with fluvial to shallow marine environments proposed within existing lithostratigraphic schemes. To produce a detailed sedimentological framework, four outcrops within the Mackenzie Mountains were measured and described to identify characteristic ichnological assemblages and sedimentological fabrics. In general, the Mount Clark Formation is represented by a regressive parasequence set. Base-level changes are expressed at parasequence boundaries, these are demarcated by sharp erosional contacts separating highly bioturbated lower shoreface strata from hummocky and trough cross-stratified middle to upper shoreface strata, and the presence of a localized Glossifungites-demarcated omission assemblage. Observed trace fossils include Skolithos, Palaeophycus Striatus, Diplocraterion, Asterosoma, Planolites, Phoebichnus, Rosselia?, Rhizocorallium?, Teichichnus, Phycodes, and Chondrites. Depending on the proximity of the studied locales to the paleo-shoreline, trace fossils tend to represent the distal Skolithos Ichnofacies in proximal settings and the archetypal Cruziana Ichnofacies in more distal positions. Bioturbation intensity and ichnological diversity tends to increase towards the offshore. Importantly tempestite beds, indicating a storm-influenced depositional setting, are observed. Unlike well-studied Mesozoic tempestites, these exhibit poorly developed to non-existent post-storm tempestite colonization trace fossil suites. Our observations firmly place the studied sections of the Mount Clark Formation in the shallow marine (offshore to shoreface) realm. Characteristically, the unit appears to have deposited during a late highstand systems tract, where accommodation was low, thus leading to the progradation and amalgamation of these units. Future work is aimed at refining the depositional and stratigraphic framework. Panel_15156 Panel_15156 8:30 AM 5:00 PM

The East China Sea Basin is a shelf basin located at the active continental margin of western Pacific. As the significant source rocks and reservoirs, the Pinghu and Huagang Formations show distinctive characters of tidal dominated delta and estuary deposition respectively. This study aims to understand the sedimentary mechanisms of the tidal dominated deposition, and how the tectonic movements and sea level change induced the transition from deltaic to estuarine environments. Seismic profiles (2D) and volumes (3D) were employed for interpreting tectonic patterns, stratigraphic framework, and large-scale (third-order) sequence stratigraphic cycles. The cores and well logs were used integrately for identifying sedimentary facies and subdividing the forth-order cycles. The Pinghu Formation spanning in the Eocene is characterized by stacked coarsening upward successions with thickness of 20 m to 40 m on well logs. The stacked, coarsening upward intervals contain the sedimentary features including thick structureless sandstone, mud drapes, fluid muds, and highly bioturbated mudstone. These sequences represent deltaic progradations on the shelf with strong tidal influences. The Huagang Formation in the Oligocene mainly consists of a series of thick, block sandbodies with thickness ranging from 15 m to 60 m on well logs. The heterolithic sandy intervals are characterized by erosive bases with mud clasts and conglomerates, bi-directional cross-beds/ripples, mud drapes, and flaser/rhythmitic beds, which indicate the tidal channel/bar deposits in an estuarine environment. On the regional stratigraphic profile, an unconformity was developed between the Pinghu and Huagang Formations, corresponding to the tectonic movement of Yuquan uplifting. This movement triggered the Diaoyu Island uplifting and relative sea level fall in the East China Sea Basin. Finally, this study reaches the conclusion that the transition from tidal-dominated deltaic to estuarine environments in the East China Sea Basin were mainly influenced by tectonic movements, subsidence, relative sea level changes, and sediment influx. During the Late Eocene, regressive cycles of tidal dominated deltas were formed in the period of relative sea level fall causing by tectonic uplifting. From the early stage of Oligocene, transgressions were developed by increasing subsidence, relative sea level rise, and less sediment supply in the East China Sea Basin, forming the tidal-dominated estuary deposition. The East China Sea Basin is a shelf basin located at the active continental margin of western Pacific. As the significant source rocks and reservoirs, the Pinghu and Huagang Formations show distinctive characters of tidal dominated delta and estuary deposition respectively. This study aims to understand the sedimentary mechanisms of the tidal dominated deposition, and how the tectonic movements and sea level change induced the transition from deltaic to estuarine environments. Seismic profiles (2D) and volumes (3D) were employed for interpreting tectonic patterns, stratigraphic framework, and large-scale (third-order) sequence stratigraphic cycles. The cores and well logs were used integrately for identifying sedimentary facies and subdividing the forth-order cycles. The Pinghu Formation spanning in the Eocene is characterized by stacked coarsening upward successions with thickness of 20 m to 40 m on well logs. The stacked, coarsening upward intervals contain the sedimentary features including thick structureless sandstone, mud drapes, fluid muds, and highly bioturbated mudstone. These sequences represent deltaic progradations on the shelf with strong tidal influences. The Huagang Formation in the Oligocene mainly consists of a series of thick, block sandbodies with thickness ranging from 15 m to 60 m on well logs. The heterolithic sandy intervals are characterized by erosive bases with mud clasts and conglomerates, bi-directional cross-beds/ripples, mud drapes, and flaser/rhythmitic beds, which indicate the tidal channel/bar deposits in an estuarine environment. On the regional stratigraphic profile, an unconformity was developed between the Pinghu and Huagang Formations, corresponding to the tectonic movement of Yuquan uplifting. This movement triggered the Diaoyu Island uplifting and relative sea level fall in the East China Sea Basin. Finally, this study reaches the conclusion that the transition from tidal-dominated deltaic to estuarine environments in the East China Sea Basin were mainly influenced by tectonic movements, subsidence, relative sea level changes, and sediment influx. During the Late Eocene, regressive cycles of tidal dominated deltas were formed in the period of relative sea level fall causing by tectonic uplifting. From the early stage of Oligocene, transgressions were developed by increasing subsidence, relative sea level rise, and less sediment supply in the East China Sea Basin, forming the tidal-dominated estuary deposition. Panel_15152 Panel_15152 8:30 AM 5:00 PM

The Upper Cretaceous Wall Creek member of the Frontier Formation in Wyoming’s Powder River Basin contains actively produced unconventional hydrocarbon reservoirs. Continued success of development of this unit partly depends on its detailed characterization. We have collected available cores and well logs from the southwestern part of the basin. Additionally, eight full stratigraphic sections and two partial stratigraphic sections were measured along a north-south traverse at the western margin of the basin. These data offer insight into local-scale and basin-scale variability of depositional environments represented by the lithofacies of the Wall Creek member. Measured sections exhibit 1-4 shallowing upward parasequences that grade up from shales, to thinly interbedded sands and shales, to amalgamated sandstone packages. Overall, there is an increase in the sandstone to shale ratio from south to north. However, the total thickness of the Wall Creek Member increases to the south. Sandstone packages range in thickness from 8 to 26 meters and contain a range of environmental and sediment transport indicators. Paleocurrent measurements from cross-stratification imply a diverse but southerly paleo-transport direction overall. Bioturbation via vertical and horizontal burrows of the thinly interbedded facies is common but not universally present. The degree of bioturbation, sandstone to shale ratio, and ichnofacies assemblages vary between and within outcrops. Some outcrops contain only Cruziana ichnofacies, whereas others contain a mixture of Cruziana and Skolithos ichnofacies. These observations support the hypothesis that these strata represent a range of depositional environments, from mixed river-wave-dominated deltaic to near shore. It is clear that there was greater accommodation in the south but that the fluvial sediment source was located in the north near Kaycee, Wyoming. Coupled with southerly longshore transport, the system preserved an asymmetrical delta and a variety of near shore lithofacies. We interpret the non-systematic variability of stacking patterns and sedimentary structures between outcrops as the result of autogenic processes in this complex depositional system. The Upper Cretaceous Wall Creek member of the Frontier Formation in Wyoming’s Powder River Basin contains actively produced unconventional hydrocarbon reservoirs. Continued success of development of this unit partly depends on its detailed characterization. We have collected available cores and well logs from the southwestern part of the basin. Additionally, eight full stratigraphic sections and two partial stratigraphic sections were measured along a north-south traverse at the western margin of the basin. These data offer insight into local-scale and basin-scale variability of depositional environments represented by the lithofacies of the Wall Creek member. Measured sections exhibit 1-4 shallowing upward parasequences that grade up from shales, to thinly interbedded sands and shales, to amalgamated sandstone packages. Overall, there is an increase in the sandstone to shale ratio from south to north. However, the total thickness of the Wall Creek Member increases to the south. Sandstone packages range in thickness from 8 to 26 meters and contain a range of environmental and sediment transport indicators. Paleocurrent measurements from cross-stratification imply a diverse but southerly paleo-transport direction overall. Bioturbation via vertical and horizontal burrows of the thinly interbedded facies is common but not universally present. The degree of bioturbation, sandstone to shale ratio, and ichnofacies assemblages vary between and within outcrops. Some outcrops contain only Cruziana ichnofacies, whereas others contain a mixture of Cruziana and Skolithos ichnofacies. These observations support the hypothesis that these strata represent a range of depositional environments, from mixed river-wave-dominated deltaic to near shore. It is clear that there was greater accommodation in the south but that the fluvial sediment source was located in the north near Kaycee, Wyoming. Coupled with southerly longshore transport, the system preserved an asymmetrical delta and a variety of near shore lithofacies. We interpret the non-systematic variability of stacking patterns and sedimentary structures between outcrops as the result of autogenic processes in this complex depositional system. Panel_15153 Panel_15153 8:30 AM 5:00 PM

Recognition of depositional processes in clastic coastal-deltaic deposits forms the basis for predicting their key reservoir properties, including dimensions, geometries, orientations and the three-dimensional distribution of petrophysical properties and reservoir heterogeneities. The application of this well-established approach can be problematic in mixed-energy coastal-deltaic systems, in which process interpretation is weakly constrained. We have addressed this problem through a detailed sedimentary facies analysis of exceptionally well-preserved and widely distributed cores, calibrated with their wireline log signatures, which enable confident process and environmental interpretations in all preserved parts of the depositional system. This study focusses on the lower, progradational part of the Lower to Middle Jurassic Ile Formation in the southern part of the Halten Terrace on the Norwegian shelf. The 100 m thick Ile formation forms the top of a 300 m thick megasequence, comprising progradational to aggradational deltaic sediments, which are overlain by a succession of retrogradational coastal deposits. The progradational to aggradational succession contains three types of regressive parasequences: (1) mixed-wave-tide influenced parasequences consist of bioturbated mudstones, which coarsen upward from micro-hummocky cross-stratified sandstones and mudstones, through intervals with increasing bidirectional current-ripple cross-lamination and into cross-bedded sandstones with mud-draped foresets and toesets; (2) mixed-wave-fluvial influenced parasequences consist of mudstones that coarsen upwards through micro-hummocky cross-stratified fine-grained sandstone and mudstone into poorly sorted coarse- to very coarse-grained sandstone; and (3) wave-dominated parasequences consist of bioturbated mudstones which pass upwards into mudstones interbedded with hummocky cross-stratified sandstones that amalgamate upwards. Parasequences observed in core have a thickness varying between 3 and 28 m, with a decrease in thickness upwards. The number and thickness of parasequences are variable laterally. The mixed-wave-fluvial influenced and mixed-wave-tide influenced parasequences are found in close association with each other, and represent active and abandoned parts of the delta, respectively. Wave-dominated parasequences are interpreted as linear coastlines lateral to the deltas. Recognition of depositional processes in clastic coastal-deltaic deposits forms the basis for predicting their key reservoir properties, including dimensions, geometries, orientations and the three-dimensional distribution of petrophysical properties and reservoir heterogeneities. The application of this well-established approach can be problematic in mixed-energy coastal-deltaic systems, in which process interpretation is weakly constrained. We have addressed this problem through a detailed sedimentary facies analysis of exceptionally well-preserved and widely distributed cores, calibrated with their wireline log signatures, which enable confident process and environmental interpretations in all preserved parts of the depositional system. This study focusses on the lower, progradational part of the Lower to Middle Jurassic Ile Formation in the southern part of the Halten Terrace on the Norwegian shelf. The 100 m thick Ile formation forms the top of a 300 m thick megasequence, comprising progradational to aggradational deltaic sediments, which are overlain by a succession of retrogradational coastal deposits. The progradational to aggradational succession contains three types of regressive parasequences: (1) mixed-wave-tide influenced parasequences consist of bioturbated mudstones, which coarsen upward from micro-hummocky cross-stratified sandstones and mudstones, through intervals with increasing bidirectional current-ripple cross-lamination and into cross-bedded sandstones with mud-draped foresets and toesets; (2) mixed-wave-fluvial influenced parasequences consist of mudstones that coarsen upwards through micro-hummocky cross-stratified fine-grained sandstone and mudstone into poorly sorted coarse- to very coarse-grained sandstone; and (3) wave-dominated parasequences consist of bioturbated mudstones which pass upwards into mudstones interbedded with hummocky cross-stratified sandstones that amalgamate upwards. Parasequences observed in core have a thickness varying between 3 and 28 m, with a decrease in thickness upwards. The number and thickness of parasequences are variable laterally. The mixed-wave-fluvial influenced and mixed-wave-tide influenced parasequences are found in close association with each other, and represent active and abandoned parts of the delta, respectively. Wave-dominated parasequences are interpreted as linear coastlines lateral to the deltas. Panel_15159 Panel_15159 8:30 AM 5:00 PM

Thin, shallow-water deltaic sandstones are important reservoirs for future reserve growth in the Bohai Bay Basin and elsewhere. In comparison with well-known thick deltaic systems that are associated with clinoformal seismic configurations, these deltaic systems have been less recognized because of the lack of visible seismic clinoforms. In this study, we identified high-order (< 20 m thick) shallow-water deltaic depositional sequences by integrating sequence-stratigraphic correlation, core and wireline-log analysis, and seismic-amplitude stratal slices in the context of depositional facies and depositional history. In the Raoyang Depression, Sha-1 to Dong-3 members of the Tertiary were recognized as third-order LST, TST, and HST deposits in a late postrift lacustrine environment. Conventional core and wireline-log analysis revealed predominantly deltaic sediments (distributary channel sands, mouth sand bars, delta-front sand sheets, and bay muds and silts) followed by meandering fluvial deposits (point-bar sands and floodplain muds). The color of interbed shales in wells grades from gray at the base to red at the top, suggesting a relative change in water depth from deep to shallow. In dip seismic sections, shingled clinoforms were observed at the base, followed by discontinuous, subparallel reflections at the top, indicating a water-depth variation from at least 50 m to less than 5 m. On amplitude stratal slices, observed seismic geomorphologic patterns range from shingled, separate channel-form/lobate systems at the base, to amplitude-zoned but continuous channel-form/lobate systems in the middle section, to meandering and arch-shaped channel-form complexes at the top. As a tentative conclusion, although shallow-water deltas with subseismic clinoforms are difficult to interpret in conventional seismic correlation, they can be expressed as characteristic amplitude-zoning patterns on stratal slices. This observation has been applied to hydrocarbon exploration in the area, with a greatly improved, successful rate of drilling. Thin, shallow-water deltaic sandstones are important reservoirs for future reserve growth in the Bohai Bay Basin and elsewhere. In comparison with well-known thick deltaic systems that are associated with clinoformal seismic configurations, these deltaic systems have been less recognized because of the lack of visible seismic clinoforms. In this study, we identified high-order (< 20 m thick) shallow-water deltaic depositional sequences by integrating sequence-stratigraphic correlation, core and wireline-log analysis, and seismic-amplitude stratal slices in the context of depositional facies and depositional history. In the Raoyang Depression, Sha-1 to Dong-3 members of the Tertiary were recognized as third-order LST, TST, and HST deposits in a late postrift lacustrine environment. Conventional core and wireline-log analysis revealed predominantly deltaic sediments (distributary channel sands, mouth sand bars, delta-front sand sheets, and bay muds and silts) followed by meandering fluvial deposits (point-bar sands and floodplain muds). The color of interbed shales in wells grades from gray at the base to red at the top, suggesting a relative change in water depth from deep to shallow. In dip seismic sections, shingled clinoforms were observed at the base, followed by discontinuous, subparallel reflections at the top, indicating a water-depth variation from at least 50 m to less than 5 m. On amplitude stratal slices, observed seismic geomorphologic patterns range from shingled, separate channel-form/lobate systems at the base, to amplitude-zoned but continuous channel-form/lobate systems in the middle section, to meandering and arch-shaped channel-form complexes at the top. As a tentative conclusion, although shallow-water deltas with subseismic clinoforms are difficult to interpret in conventional seismic correlation, they can be expressed as characteristic amplitude-zoning patterns on stratal slices. This observation has been applied to hydrocarbon exploration in the area, with a greatly improved, successful rate of drilling. Panel_15154 Panel_15154 8:30 AM 5:00 PM

Marginal marine systems show a significant degree of variability that is not described in most widely used depositional models. A careful examination of a large number of modern and ancient systems demonstrates that: (1) mixed-influence systems (Fw, Ft, Fwt, Ftw, Wf, Wt, Wft, Wtf, Tw, Tf, Twf, Tfw) are much more common in the geological record than fluvial-dominated (F), wave-dominated (W), and tide-dominated (T) end members; (2) there is often a significant process and architectural variability within the same regressive or transgressive sediment package (intra-parasequence scale); (3) there can be a continuum between different depositional environment types in the same system; (4) shoreline deposition can be affected by fluvial distributive networks formed by avulsions on the delta plain or avulsions further upstream as part of larger megafan systems, which can result in different stratigraphic architecture; (5) a system can contain different scales of discontinuities, which can be either regional or of limited lateral extent; (6) the same system can contain lobate shoreline components, linear shoreline components and transitional linear-to-lobate components. A practical way of dealing with such variability is adopting a hierarchical classification framework, where issues occurring at specific architectural scales can be addressed. Such an approach allows describing architecture deposited over hundreds of thousands to millions of years (e.g., the nature of stacking of regressive and transgressive packages), thousands to tens of thousand of years (e.g., extent of individual transgressive or regressive packages; major changes in process or sediment depocenters within such packages), tens to hundreds of years (e.g., progradation pulses and internal facies association variability within individual delta lobes), months to years (formation of individual mouth bars). The variability within each hierarchy level is then described in terms of a limited set of architectural categories that are related to process. Investigating the possible links between categories belonging to different hierarchy levels allows a component of prediction, where parent, child and sibling units can be identified. We show a number of worked modern and ancient examples that describe how the classification system can be used in practice, and how this approach can be used for prediction, uncertainty management, and compiling geospatial data and databases. Marginal marine systems show a significant degree of variability that is not described in most widely used depositional models. A careful examination of a large number of modern and ancient systems demonstrates that: (1) mixed-influence systems (Fw, Ft, Fwt, Ftw, Wf, Wt, Wft, Wtf, Tw, Tf, Twf, Tfw) are much more common in the geological record than fluvial-dominated (F), wave-dominated (W), and tide-dominated (T) end members; (2) there is often a significant process and architectural variability within the same regressive or transgressive sediment package (intra-parasequence scale); (3) there can be a continuum between different depositional environment types in the same system; (4) shoreline deposition can be affected by fluvial distributive networks formed by avulsions on the delta plain or avulsions further upstream as part of larger megafan systems, which can result in different stratigraphic architecture; (5) a system can contain different scales of discontinuities, which can be either regional or of limited lateral extent; (6) the same system can contain lobate shoreline components, linear shoreline components and transitional linear-to-lobate components. A practical way of dealing with such variability is adopting a hierarchical classification framework, where issues occurring at specific architectural scales can be addressed. Such an approach allows describing architecture deposited over hundreds of thousands to millions of years (e.g., the nature of stacking of regressive and transgressive packages), thousands to tens of thousand of years (e.g., extent of individual transgressive or regressive packages; major changes in process or sediment depocenters within such packages), tens to hundreds of years (e.g., progradation pulses and internal facies association variability within individual delta lobes), months to years (formation of individual mouth bars). The variability within each hierarchy level is then described in terms of a limited set of architectural categories that are related to process. Investigating the possible links between categories belonging to different hierarchy levels allows a component of prediction, where parent, child and sibling units can be identified. We show a number of worked modern and ancient examples that describe how the classification system can be used in practice, and how this approach can be used for prediction, uncertainty management, and compiling geospatial data and databases. Panel_15150 Panel_15150 8:30 AM 5:00 PM

Coastal plain to open shelf sediments are transported and deposited through the complex interaction of continental and marine processes. The physical transition from non-marine to marine process regimes is documented along dip profiles of ancient regressive systems. Less commonly documented, however, is the lateral (strike) variability of transitional successions and basin margin progradation, although this can impact reservoir architecture. In the Karoo Basin, continuous NW-SE oriented outcrop exposes more than 200 km of the basin margin. Eight 500m logged sections with 4-15 km spacing were correlated and tied to detailed photo panoramas along a 70km long transect. Successions of 5-25m thick packages of current ripple laminated, thin-bedded inverse to normally graded and dirty siltstone (St)-sandstone (Sd), are interpreted as prodelta lobes of a river-dominated partly wave-reworked system. Where these are sand-prone with climbing ripples they are interpreted as distal mouth bars. Structureless Sd in channel-forms that incise into fine-grained St is interpreted as distributary channels cutting into bay-fill mudstones in the lower delta plain. Laterally, these successions pass into thickening upwards units with thin-bedded and lenticular Sd with symmetrical ripple forms overlain by clean Sd containing convex-up lamination or to amalgamated Sd. These are interpreted as shoreface-to-offshore transition to shoreface units. More than 2500 paleocurrents show dominant transport to the N-NE, with local E-W and NE-SW bidirectional components confirming that the section is a regional strike to oblique-strike orientation. Seven correlated units summarize the stratigraphic evolution. The overall succession, and regional context, reflects the progradation of the basin margin to the NE. However, the mixed influence of river- and wave-dominated process regimes leads to a more complicated depositional architecture along strike. Although the nearshore environments were river-dominated, the paleocurrents and lateral changes in depositional environments and sand cleanness suggest that there was across shelf sediment transport by waves and storms. The marine to non-marine transition shows mixed influence shoreline systems evolving through time in a non-coal-bearing, moderate to high-latitude paleo-climatic setting, providing a good example of architecture heterogeneity in paralic reservoirs. Coastal plain to open shelf sediments are transported and deposited through the complex interaction of continental and marine processes. The physical transition from non-marine to marine process regimes is documented along dip profiles of ancient regressive systems. Less commonly documented, however, is the lateral (strike) variability of transitional successions and basin margin progradation, although this can impact reservoir architecture. In the Karoo Basin, continuous NW-SE oriented outcrop exposes more than 200 km of the basin margin. Eight 500m logged sections with 4-15 km spacing were correlated and tied to detailed photo panoramas along a 70km long transect. Successions of 5-25m thick packages of current ripple laminated, thin-bedded inverse to normally graded and dirty siltstone (St)-sandstone (Sd), are interpreted as prodelta lobes of a river-dominated partly wave-reworked system. Where these are sand-prone with climbing ripples they are interpreted as distal mouth bars. Structureless Sd in channel-forms that incise into fine-grained St is interpreted as distributary channels cutting into bay-fill mudstones in the lower delta plain. Laterally, these successions pass into thickening upwards units with thin-bedded and lenticular Sd with symmetrical ripple forms overlain by clean Sd containing convex-up lamination or to amalgamated Sd. These are interpreted as shoreface-to-offshore transition to shoreface units. More than 2500 paleocurrents show dominant transport to the N-NE, with local E-W and NE-SW bidirectional components confirming that the section is a regional strike to oblique-strike orientation. Seven correlated units summarize the stratigraphic evolution. The overall succession, and regional context, reflects the progradation of the basin margin to the NE. However, the mixed influence of river- and wave-dominated process regimes leads to a more complicated depositional architecture along strike. Although the nearshore environments were river-dominated, the paleocurrents and lateral changes in depositional environments and sand cleanness suggest that there was across shelf sediment transport by waves and storms. The marine to non-marine transition shows mixed influence shoreline systems evolving through time in a non-coal-bearing, moderate to high-latitude paleo-climatic setting, providing a good example of architecture heterogeneity in paralic reservoirs. Panel_15157 Panel_15157 8:30 AM 5:00 PM

The inherent deformation due to the growth of normal faults in an extensional basin results in mechanisms such as rotation and subsidence of the hangingwall and syncline growth that constitute first order modifiers of the substrate gradients. Their interaction with the marine environment can result in an intricate development of straits and embayments affecting the circulation of marine currents. The impact of these structural induced features is studied by a combination of traditional field methods and digital outcrop techniques (LIDAR and photogrammetry) from very well preserved Miocene early syn-rift exposures at the Nezzazat Fault System, Suez Rift, Sinai Peninsula, Egypt. The early syn-rift succession is composed of shallow marine carbonates and siliciclastics of early Miocene age (Aquitanian) found in a series of synclines developed in a terrace zone along the El Qaa half-graben’s western border (Nezzazat Fault System). They are constituted by bioclastic rudstones and conglomerates forming 2 to 8 m thick cross-bedded sets, intercalated by 1.5 to 9 m mudstone-rich intervals containing some millimetric silty horizons and a few floating pebbles. Rudstones appear in 20 to 50 cm thick tabular beds with sharp planar bases and tops. The conglomerates are well sorted 30 cm thick beds, made of rounded to subrounded equant and prolate coarse pebbles to cobbles with fine to medium boulders derived from the pre-rift lithologies. The cross-bedded sets resulted from the migration of 3D dunes. Detailed analysis of their geometries and palaeotransport directions show a preferred orientation aligned parallel to the syncline axes and the main normal faults. The deposition of the dunes was synchronous with the formation of the synclines and growth of the normal faults in the area. The deposits in the area consistently thin towards the syncline limbs while they thicken towards their axes. Thickness variations also occur consistently along strike the syncline axes, following its dip direction. Reconstruction of the 3D geometry of the syn-rift units preserved in the area together with the main extensional structures suggests that the dunes were deposited along a shallow structural strait with local embayments, less than 1.5 km wide than prolonged for at least 5 km parallel to a depocentre’s border fault system. The inherent deformation due to the growth of normal faults in an extensional basin results in mechanisms such as rotation and subsidence of the hangingwall and syncline growth that constitute first order modifiers of the substrate gradients. Their interaction with the marine environment can result in an intricate development of straits and embayments affecting the circulation of marine currents. The impact of these structural induced features is studied by a combination of traditional field methods and digital outcrop techniques (LIDAR and photogrammetry) from very well preserved Miocene early syn-rift exposures at the Nezzazat Fault System, Suez Rift, Sinai Peninsula, Egypt. The early syn-rift succession is composed of shallow marine carbonates and siliciclastics of early Miocene age (Aquitanian) found in a series of synclines developed in a terrace zone along the El Qaa half-graben’s western border (Nezzazat Fault System). They are constituted by bioclastic rudstones and conglomerates forming 2 to 8 m thick cross-bedded sets, intercalated by 1.5 to 9 m mudstone-rich intervals containing some millimetric silty horizons and a few floating pebbles. Rudstones appear in 20 to 50 cm thick tabular beds with sharp planar bases and tops. The conglomerates are well sorted 30 cm thick beds, made of rounded to subrounded equant and prolate coarse pebbles to cobbles with fine to medium boulders derived from the pre-rift lithologies. The cross-bedded sets resulted from the migration of 3D dunes. Detailed analysis of their geometries and palaeotransport directions show a preferred orientation aligned parallel to the syncline axes and the main normal faults. The deposition of the dunes was synchronous with the formation of the synclines and growth of the normal faults in the area. The deposits in the area consistently thin towards the syncline limbs while they thicken towards their axes. Thickness variations also occur consistently along strike the syncline axes, following its dip direction. Reconstruction of the 3D geometry of the syn-rift units preserved in the area together with the main extensional structures suggests that the dunes were deposited along a shallow structural strait with local embayments, less than 1.5 km wide than prolonged for at least 5 km parallel to a depocentre’s border fault system. Panel_15155 Panel_15155 8:30 AM 5:00 PM

In overfilled lacustrine basins deltas are deposited at the level of the outflow sill where rivers enter the lake. Thus, they are ideally positioned to record even subtle fluctuations in lake level caused by changes in discharge and basin subsidence. In balanced-fill basins the fluvial-deltaic environment can migrate tens of kilometers laterally almost instantaneously since lake level is not pinned at the elevation of the outflow sill. The Farson Sandstone Member, deposited in the Greater Green River Basin (GGRB) of Wyoming, is a fluvial-deltaic sandstone unit which covered nearly one third of the basin during a period of lake basin evolution between overfilled and balanced-fill conditions. In addition to recording basin-scale changes in subsidence and sediment supply, detailed stratigraphic study of the Farson Sandstone and laterally equivalent Tipton Shale Member has shown that paleotopography on the basin floor influenced the distribution of lithofacies. In particular, recognition of a paleohigh seems to explain the presence of a series of enigmatic mounded facies possibly related to spring discharge and microbial activity. Ten detailed stratigraphic measured sections of the Farson Sandstone Member and interbedded Tipton Shale Member were described in the summer of 2014 in southwestern WY and integrated with those of previous studies. This combined data set provides a high resolution two-dimensional stratigraphic framework to define lateral and vertical lithofacies distributions and significant stratal surfaces along a depositional dip transect. This data allows for a better understanding of the depositional history of the GGRB as it relates to basin subsidence, water discharge, and sediment supply. Interpretations produced by this study can act as analogues for other lacustrine basins. In overfilled lacustrine basins deltas are deposited at the level of the outflow sill where rivers enter the lake. Thus, they are ideally positioned to record even subtle fluctuations in lake level caused by changes in discharge and basin subsidence. In balanced-fill basins the fluvial-deltaic environment can migrate tens of kilometers laterally almost instantaneously since lake level is not pinned at the elevation of the outflow sill. The Farson Sandstone Member, deposited in the Greater Green River Basin (GGRB) of Wyoming, is a fluvial-deltaic sandstone unit which covered nearly one third of the basin during a period of lake basin evolution between overfilled and balanced-fill conditions. In addition to recording basin-scale changes in subsidence and sediment supply, detailed stratigraphic study of the Farson Sandstone and laterally equivalent Tipton Shale Member has shown that paleotopography on the basin floor influenced the distribution of lithofacies. In particular, recognition of a paleohigh seems to explain the presence of a series of enigmatic mounded facies possibly related to spring discharge and microbial activity. Ten detailed stratigraphic measured sections of the Farson Sandstone Member and interbedded Tipton Shale Member were described in the summer of 2014 in southwestern WY and integrated with those of previous studies. This combined data set provides a high resolution two-dimensional stratigraphic framework to define lateral and vertical lithofacies distributions and significant stratal surfaces along a depositional dip transect. This data allows for a better understanding of the depositional history of the GGRB as it relates to basin subsidence, water discharge, and sediment supply. Interpretations produced by this study can act as analogues for other lacustrine basins. Panel_15158 Panel_15158 8:30 AM 5:00 PM

Panel_14452 Panel_14452 8:30 AM 5:00 PM

With recent advances in technology, North American shale gas plays are now considered to be well defined. But, the relative lack of success elsewhere in the world, is a reminder that there are shales - and there are shales. By better defining depositional controls, can missed opportunities in North America be identified, and applied to reduce unconventionals risk globally? To identify new shale gas opportunities within North America, our methodology focuses on depositional factors, by reconstructing and modelling those processes which affect shale depositional systems. Fundamental to this is to reconstruct the sediment system, from source to sink. Reconstruction of the structural and tectonic framework of North America acts as a foundation for detailed paleogeographic reconstructions of the tectonic and depositional history of the North American Plate. This is important, as it relates to sediment supply (uplift, weathering, erosion and transport). The depositional environments are mapped according to their gross depositional environment, which, when combined with lithology, provides information on facies. These reconstructions are then converted to paleolandscapes, within which are reconstructed paleodrainage systems, derived from analysis of Present Day river networks, provenance data and paleocurrent directions. Earth Systems Modelling gives insight into contemporary climatic conditions, this is an important controlling factor on weathering in the hinterland. This affects the nature of the eroded sediments, the process of their transportation and their routing to the sink area. Ocean and tide models are then used to deduce the submarine sediment transport pathways. Through the integration of these data an informed interpretation of the nature and extent of deposition in the sink areas can be reached. By adding modelled outputs of processes including productivity, upwelling, oxygen saturation and calibrating these with measured geochemical source rock richness data, insight can be gained into not only the distribution of shales, but also a calibrated, quantitative prediction of the depositional quality of the shale can be achieved. Through the application of these methods, and integration of the knowledge that has been accrued through exploration over time, our aim is to establish a more effective method of shale gas exploration, which could then be applied on a global scale. With recent advances in technology, North American shale gas plays are now considered to be well defined. But, the relative lack of success elsewhere in the world, is a reminder that there are shales - and there are shales. By better defining depositional controls, can missed opportunities in North America be identified, and applied to reduce unconventionals risk globally? To identify new shale gas opportunities within North America, our methodology focuses on depositional factors, by reconstructing and modelling those processes which affect shale depositional systems. Fundamental to this is to reconstruct the sediment system, from source to sink. Reconstruction of the structural and tectonic framework of North America acts as a foundation for detailed paleogeographic reconstructions of the tectonic and depositional history of the North American Plate. This is important, as it relates to sediment supply (uplift, weathering, erosion and transport). The depositional environments are mapped according to their gross depositional environment, which, when combined with lithology, provides information on facies. These reconstructions are then converted to paleolandscapes, within which are reconstructed paleodrainage systems, derived from analysis of Present Day river networks, provenance data and paleocurrent directions. Earth Systems Modelling gives insight into contemporary climatic conditions, this is an important controlling factor on weathering in the hinterland. This affects the nature of the eroded sediments, the process of their transportation and their routing to the sink area. Ocean and tide models are then used to deduce the submarine sediment transport pathways. Through the integration of these data an informed interpretation of the nature and extent of deposition in the sink areas can be reached. By adding modelled outputs of processes including productivity, upwelling, oxygen saturation and calibrating these with measured geochemical source rock richness data, insight can be gained into not only the distribution of shales, but also a calibrated, quantitative prediction of the depositional quality of the shale can be achieved. Through the application of these methods, and integration of the knowledge that has been accrued through exploration over time, our aim is to establish a more effective method of shale gas exploration, which could then be applied on a global scale. Panel_15163 Panel_15163 8:30 AM 5:00 PM

The Eagle Plain, located in the Northeastern Yukon Territory, Canada, forms a northern segment of the Cretaceous Western Interior Sea. Its preserved Cretaceous strata document the initial inundation of northwestern Canada by the Polar Sea. Preserved strata are the result of an active structural regime, sea-level fluctuations and changing sediment supply areas. The Cretaceous rocks are unconformably underlain by either Paleozoic or younger Mesozoic formations. Recent paleontological evidence including pollen, foraminifera and macrofossils from outcrop sections in the Eagle Plain suggested that Aptian to Cenomanian aged strata are preserved. This package includes the Whitestone River, Parkin, Fishing Branch, Burnthill Creek and Cody Creek formations. The area became terrestrially exposed during the upper Cretaceous when paleoshorelines moved northward and eastward to the Peel Plateau region. This project takes this new stratigraphy into the subsurface by examining two cores and their foraminiferal assemblages that represent proximal shelf and slope settings. In both regions foraminiferal assemblages are almost entirely dominated by agglutinated taxa and document response to fluctuating sea-level changes during the Albian Stage. The Ellen C-24 core represents a proximal shelf setting where the lower to middle Albian Whitestone River Formation is fully marine with hospitable benthic conditions. The Molar P-34 well represents an offshore setting with increased accommodation space marked by sediment slumping, representing a northwestward deepening of the basin. The deep water setting is evidenced by abundant tubular suspension feeders which are rarer in the Ellen C-24 core. In both settings a marked lithological change from shale to sandstone takes place within the upper Albian Parkin Formation corresponding to a distinct faunal changeover to an impoverished fauna. This shallowing event alludes to a regionally recognizable late Albian sea-level drop that is expressed in the Peel Plateau region as a paleosol, but remains elusive in the lithology of the Eagle Plain. The distinct faunal loss, however, clearly marks a basin change. The Whitestone River Formation documents Aptian/Albian sea-level fluctuations that can be correlated to the Polar Sea and Sverdrup Basin to the North and to southern basins of the Western Interior Sea. The Eagle Plain, located in the Northeastern Yukon Territory, Canada, forms a northern segment of the Cretaceous Western Interior Sea. Its preserved Cretaceous strata document the initial inundation of northwestern Canada by the Polar Sea. Preserved strata are the result of an active structural regime, sea-level fluctuations and changing sediment supply areas. The Cretaceous rocks are unconformably underlain by either Paleozoic or younger Mesozoic formations. Recent paleontological evidence including pollen, foraminifera and macrofossils from outcrop sections in the Eagle Plain suggested that Aptian to Cenomanian aged strata are preserved. This package includes the Whitestone River, Parkin, Fishing Branch, Burnthill Creek and Cody Creek formations. The area became terrestrially exposed during the upper Cretaceous when paleoshorelines moved northward and eastward to the Peel Plateau region. This project takes this new stratigraphy into the subsurface by examining two cores and their foraminiferal assemblages that represent proximal shelf and slope settings. In both regions foraminiferal assemblages are almost entirely dominated by agglutinated taxa and document response to fluctuating sea-level changes during the Albian Stage. The Ellen C-24 core represents a proximal shelf setting where the lower to middle Albian Whitestone River Formation is fully marine with hospitable benthic conditions. The Molar P-34 well represents an offshore setting with increased accommodation space marked by sediment slumping, representing a northwestward deepening of the basin. The deep water setting is evidenced by abundant tubular suspension feeders which are rarer in the Ellen C-24 core. In both settings a marked lithological change from shale to sandstone takes place within the upper Albian Parkin Formation corresponding to a distinct faunal changeover to an impoverished fauna. This shallowing event alludes to a regionally recognizable late Albian sea-level drop that is expressed in the Peel Plateau region as a paleosol, but remains elusive in the lithology of the Eagle Plain. The distinct faunal loss, however, clearly marks a basin change. The Whitestone River Formation documents Aptian/Albian sea-level fluctuations that can be correlated to the Polar Sea and Sverdrup Basin to the North and to southern basins of the Western Interior Sea. Panel_15165 Panel_15165 8:30 AM 5:00 PM

Southwestern Energy has drilled over 4,000 wells in the Mississippian Fayetteville Shale Formation across nearly one million acres in Arkansas, revealing that productivity and calculated GIP varies significantly throughout the lease area. Early hypotheses attributed these variations in production to mineralogical changes, which were subsequently not observed at the log scale. This study assesses if changes in productivity are controlled by fabric or textural properties of the rock. Petrographic analysis of 561 thin sections from 9 wells across the lease area was conducted and textural variability was documented both laterally and vertically through the stratigraphic intervals of the Fayetteville Shale. Additionally, XRD analysis was performed on 175 samples. Petrographic analysis shows that the Fayetteville Shale consists of five main facies based on texture, diagenesis, mineralogy, and organic content: siliceous organic-rich, mixed siliceous-argillaceous, carbonate-rich, argillaceous laminated, and silty argillaceous mudstones. Reservoir intervals in the Lower Fayetteville Shale are characterized by the siliceous organic-rich mudstone facies that are punctuated by zones of the mixed siliceous-argillaceous or carbonate-rich mudstone facies. Quartz, calcite and dolomite cement are the most common pore-reducing authigenic phases along with varying amounts of phosphate, pyrite, chlorite, kaolinite, and siderite. Silica is an important component of the Fayetteville Shale and it is primarily biogenic and not detrital in origin. The silica is sourced from radiolaria and sponge spicules (opal-A), which are highly unstable and undergo early diagenesis near the sediment-water interface. A more stable form of silica precipitated as chert in the matrix and filled Tasmanites algal cysts. Tasmanites are a common microfossil in the siliceous organic-rich mudstone facies. The abundance of phosphate, pyrite, and organisms such as radiolaria and Tasmanites in organic-rich sediment indicate that the Lower Fayetteville Shale reservoir intervals were deposited under high productivity and anoxic to suboxic conditions in a coastal upwelling system. A strong correlation between silica and TOC can be demonstrated and is related to high biogenic activity in algal blooms during upwelling. The distribution of silica both vertically and laterally is thus an essential control on reservoir quality. Southwestern Energy has drilled over 4,000 wells in the Mississippian Fayetteville Shale Formation across nearly one million acres in Arkansas, revealing that productivity and calculated GIP varies significantly throughout the lease area. Early hypotheses attributed these variations in production to mineralogical changes, which were subsequently not observed at the log scale. This study assesses if changes in productivity are controlled by fabric or textural properties of the rock. Petrographic analysis of 561 thin sections from 9 wells across the lease area was conducted and textural variability was documented both laterally and vertically through the stratigraphic intervals of the Fayetteville Shale. Additionally, XRD analysis was performed on 175 samples. Petrographic analysis shows that the Fayetteville Shale consists of five main facies based on texture, diagenesis, mineralogy, and organic content: siliceous organic-rich, mixed siliceous-argillaceous, carbonate-rich, argillaceous laminated, and silty argillaceous mudstones. Reservoir intervals in the Lower Fayetteville Shale are characterized by the siliceous organic-rich mudstone facies that are punctuated by zones of the mixed siliceous-argillaceous or carbonate-rich mudstone facies. Quartz, calcite and dolomite cement are the most common pore-reducing authigenic phases along with varying amounts of phosphate, pyrite, chlorite, kaolinite, and siderite. Silica is an important component of the Fayetteville Shale and it is primarily biogenic and not detrital in origin. The silica is sourced from radiolaria and sponge spicules (opal-A), which are highly unstable and undergo early diagenesis near the sediment-water interface. A more stable form of silica precipitated as chert in the matrix and filled Tasmanites algal cysts. Tasmanites are a common microfossil in the siliceous organic-rich mudstone facies. The abundance of phosphate, pyrite, and organisms such as radiolaria and Tasmanites in organic-rich sediment indicate that the Lower Fayetteville Shale reservoir intervals were deposited under high productivity and anoxic to suboxic conditions in a coastal upwelling system. A strong correlation between silica and TOC can be demonstrated and is related to high biogenic activity in algal blooms during upwelling. The distribution of silica both vertically and laterally is thus an essential control on reservoir quality. Panel_15167 Panel_15167 8:30 AM 5:00 PM

This study reports organic-rich shale in Kimmeridgian Jhuran Formation in western India and discusses effects of small-scale igneous dyke intrusions on textural and geochemical characteristics of the shale. Field, petrography, Rock-Eval pyrolysis and GC-MS data are presented to document changes in texture and geochemistry for the systematically collected samples in relation to the distance of dykes in outcrop. Unconformably resting over a carbonate succession, the overall coarsening-upward Jhuran Formation exhibits laterally extensive organic-rich shale (average thickness ~60 m) in the lower and middle segments, which are intervened by siltstone and sandstone interbeds of variable thicknesses. Inner to middle-shelf origin of the carbonaceous shale is inferred by abundant plant leaves in shales, hummocky cross-stratified and wave rippled sandstones, polymodal paleocurrent direction of sole marks and trace fossils Gyrochorte, Arenicolites, Skolithos, Planolites. TOC content of shales vary from 1.7% to 7.5%, with an average Tmax 430°C. HI and OI range from 46 to 15 and 19 to 71 mg HC/g Corg respectively, suggesting dominance of type-III kerogen. Phyllocladane, ent-kaurane, retene and simonellite dominates the biomarker assemblage indicating predominantly coniferal source of organic matter. Mafic igneous dykes (75-68 Ma old) intrude the shale at several localities, altering its textural and geochemical characteristics. The dykes form an intensely burnt zone within the shale at its contact to about 2 m, and a weakly burnt zone up to around 8 m distance. Average Tmax value of samples at the intensely burnt zone is around 595°C. Original wavy and lenticular micro-texture of shale is completely lost as quartz silts exhibits floating texture within organic-rich matrix. Biomarker is represented by poly-aromatic fractions such as fluroanthrene, pyrene, benzo-fluorene, methylated pyrenes, benzo-naptho-thiophenes, anthracenes. Tmax sharply drops to ~460°C and thereafter it decreases gradually within the weakly burnt zone. Average HI and OI values of the intensely burnt zone are 10 and 20 mg HC/g Corg respectively which increase gradually as the wavy and lenticular micro-texture of shale gradually reappears with increasing distance from dykes. This study documents a sharp rise of Tmax and sharp fall in HI and OI in the intensely burnt zone adjacent to dykes and gradual changes in these parameters within the weakly burnt zone to the unaffected zone. This study reports organic-rich shale in Kimmeridgian Jhuran Formation in western India and discusses effects of small-scale igneous dyke intrusions on textural and geochemical characteristics of the shale. Field, petrography, Rock-Eval pyrolysis and GC-MS data are presented to document changes in texture and geochemistry for the systematically collected samples in relation to the distance of dykes in outcrop. Unconformably resting over a carbonate succession, the overall coarsening-upward Jhuran Formation exhibits laterally extensive organic-rich shale (average thickness ~60 m) in the lower and middle segments, which are intervened by siltstone and sandstone interbeds of variable thicknesses. Inner to middle-shelf origin of the carbonaceous shale is inferred by abundant plant leaves in shales, hummocky cross-stratified and wave rippled sandstones, polymodal paleocurrent direction of sole marks and trace fossils Gyrochorte, Arenicolites, Skolithos, Planolites. TOC content of shales vary from 1.7% to 7.5%, with an average Tmax 430°C. HI and OI range from 46 to 15 and 19 to 71 mg HC/g Corg respectively, suggesting dominance of type-III kerogen. Phyllocladane, ent-kaurane, retene and simonellite dominates the biomarker assemblage indicating predominantly coniferal source of organic matter. Mafic igneous dykes (75-68 Ma old) intrude the shale at several localities, altering its textural and geochemical characteristics. The dykes form an intensely burnt zone within the shale at its contact to about 2 m, and a weakly burnt zone up to around 8 m distance. Average Tmax value of samples at the intensely burnt zone is around 595°C. Original wavy and lenticular micro-texture of shale is completely lost as quartz silts exhibits floating texture within organic-rich matrix. Biomarker is represented by poly-aromatic fractions such as fluroanthrene, pyrene, benzo-fluorene, methylated pyrenes, benzo-naptho-thiophenes, anthracenes. Tmax sharply drops to ~460°C and thereafter it decreases gradually within the weakly burnt zone. Average HI and OI values of the intensely burnt zone are 10 and 20 mg HC/g Corg respectively which increase gradually as the wavy and lenticular micro-texture of shale gradually reappears with increasing distance from dykes. This study documents a sharp rise of Tmax and sharp fall in HI and OI in the intensely burnt zone adjacent to dykes and gradual changes in these parameters within the weakly burnt zone to the unaffected zone. Panel_15166 Panel_15166 8:30 AM 5:00 PM

The Kanguk Formation is a Cenomanian-Maastrichtian source rock in the Sverdrup Basin. Source rocks of similar age are also present to the west of the basin and may be present in Baffin Bay. In 2013 and 2014 three sections were logged through the Kanguk Formation on Ellesmere and Axel Heiberg islands. The basal contact of the Kanguk Formation is sharp. On Ellesmere Island Kanguk Formation shales overlie deltaic sandstones of the Albian-Cenomanian Hassel Formation; on Axel Heiberg Island they overlie the Strand Fiord Formation volcanic rocks of the High Arctic Large Igneous Province. Dark shales, showing traces of bioturbation near the base of the formation indicate an offshore environment below storm wave base. These are overlain by black, papery, bituminous shales, which potentially indicate anoxic bottom water conditions during the OAE 2. Bentonites are abundant in this part of the succession but occur throughout. Upwards, thin, silty layers exhibiting faint cross lamination become more common. Higher up in the section, on Axel Heiberg Island, these beds are arranged in several coarsening-upward cycles that contain hummocky cross stratification indicating deposition in a lower shoreface setting. These sediments are overlain by a more homogeneous, silty interval containing several distinct, red weathering horizons with abundant Late Santonian to Early Campanian Inoceramid shells. This interval is present in the upper part of all three sections and appears to be a marker horizon. Near the top of the formation grain size increases rapidly. Herringbone cross stratification and mud drapes indicate a tidal environment. These beds grade into very low angle cross bedded beach sandstones. Overlying trough cross bedded sandstones with basal conglomerates and reworked red mudclasts indicate a rapid facies change from shoreface to fluvial deposition at the base of the Paleogene Eureka Sound Group. The thickness of the Kanguk Formation decreases from +500 m in the basinal setting on Axel Heiberg Island to approximately 130 m in the most marginal section on Ellesmere Island. Shale samples were collected at meter intervals from the formation for ongoing TOC, biomarker and palynological analyses, Rock Eval Pyrolysis, kerogen typing, vitrinite reflectance, mudstone petrography, XRD, and microfossils studies. Zircons were separated from bentonites for ongoing U-Pb age dating using ion-microprobes and chemical abrasion isotope dilution thermal ionization mass spectrometry. The Kanguk Formation is a Cenomanian-Maastrichtian source rock in the Sverdrup Basin. Source rocks of similar age are also present to the west of the basin and may be present in Baffin Bay. In 2013 and 2014 three sections were logged through the Kanguk Formation on Ellesmere and Axel Heiberg islands. The basal contact of the Kanguk Formation is sharp. On Ellesmere Island Kanguk Formation shales overlie deltaic sandstones of the Albian-Cenomanian Hassel Formation; on Axel Heiberg Island they overlie the Strand Fiord Formation volcanic rocks of the High Arctic Large Igneous Province. Dark shales, showing traces of bioturbation near the base of the formation indicate an offshore environment below storm wave base. These are overlain by black, papery, bituminous shales, which potentially indicate anoxic bottom water conditions during the OAE 2. Bentonites are abundant in this part of the succession but occur throughout. Upwards, thin, silty layers exhibiting faint cross lamination become more common. Higher up in the section, on Axel Heiberg Island, these beds are arranged in several coarsening-upward cycles that contain hummocky cross stratification indicating deposition in a lower shoreface setting. These sediments are overlain by a more homogeneous, silty interval containing several distinct, red weathering horizons with abundant Late Santonian to Early Campanian Inoceramid shells. This interval is present in the upper part of all three sections and appears to be a marker horizon. Near the top of the formation grain size increases rapidly. Herringbone cross stratification and mud drapes indicate a tidal environment. These beds grade into very low angle cross bedded beach sandstones. Overlying trough cross bedded sandstones with basal conglomerates and reworked red mudclasts indicate a rapid facies change from shoreface to fluvial deposition at the base of the Paleogene Eureka Sound Group. The thickness of the Kanguk Formation decreases from +500 m in the basinal setting on Axel Heiberg Island to approximately 130 m in the most marginal section on Ellesmere Island. Shale samples were collected at meter intervals from the formation for ongoing TOC, biomarker and palynological analyses, Rock Eval Pyrolysis, kerogen typing, vitrinite reflectance, mudstone petrography, XRD, and microfossils studies. Zircons were separated from bentonites for ongoing U-Pb age dating using ion-microprobes and chemical abrasion isotope dilution thermal ionization mass spectrometry. Panel_15162 Panel_15162 8:30 AM 5:00 PM

The anisotropy of magnetic susceptibility (AMS) in most shale units is characterized by a normal magnetic fabric where the magnetic foliation is parallel to the bedding plane with a distinctly oblate shape. New AMS data from the Woodford and Marcellus shales show anomalous AMS signatures with a magnetic foliation perpendicular to the bedding plane and a mixed prolate/oblate fabric. The acquisition of these magnetic fabrics may be explained by the following processes: (1) fluid filled fractures displacing adjacent ferromagnetic and paramagnetic grains; (2) bioturbation; (3) inverse magnetic fabrics carried by single domain magnetite or goethite; (4) granular rotation of magnetic carrier minerals in localized viscoplastic zones (5) and authigenic ferromagnetic and minerals formed in association with fluid events. Preliminary observations of the Woodford shale suggest that anomalous AMS fabrics are associated with localized vertical/sub vertical fluid filled fractures however, further investigation is required. Observations of the Marcellus shale indicate an association between anomalous AMS fabrics and localized viscoplastic zones. Paleomagnetic and rock magnetic investigations reveal that the dominant magnetic carrier mineral is magnetite for both shale units. The degree of anisotropy (P’) in both the Woodford and Marcellus shales increases with depth, suggesting fabric stretching in response to overburden. The average shape factor (T) in the Marcellus shale is oblate. The average T in the Woodford shale is prolate. Significant spatial variability of magnetic susceptibility is observed in both shales, suggesting a complex magnetic mineralogy. An understanding of anomalous AMS fabric development in these shales units can provide insight into fluid flow processes. The anisotropy of magnetic susceptibility (AMS) in most shale units is characterized by a normal magnetic fabric where the magnetic foliation is parallel to the bedding plane with a distinctly oblate shape. New AMS data from the Woodford and Marcellus shales show anomalous AMS signatures with a magnetic foliation perpendicular to the bedding plane and a mixed prolate/oblate fabric. The acquisition of these magnetic fabrics may be explained by the following processes: (1) fluid filled fractures displacing adjacent ferromagnetic and paramagnetic grains; (2) bioturbation; (3) inverse magnetic fabrics carried by single domain magnetite or goethite; (4) granular rotation of magnetic carrier minerals in localized viscoplastic zones (5) and authigenic ferromagnetic and minerals formed in association with fluid events. Preliminary observations of the Woodford shale suggest that anomalous AMS fabrics are associated with localized vertical/sub vertical fluid filled fractures however, further investigation is required. Observations of the Marcellus shale indicate an association between anomalous AMS fabrics and localized viscoplastic zones. Paleomagnetic and rock magnetic investigations reveal that the dominant magnetic carrier mineral is magnetite for both shale units. The degree of anisotropy (P’) in both the Woodford and Marcellus shales increases with depth, suggesting fabric stretching in response to overburden. The average shape factor (T) in the Marcellus shale is oblate. The average T in the Woodford shale is prolate. Significant spatial variability of magnetic susceptibility is observed in both shales, suggesting a complex magnetic mineralogy. An understanding of anomalous AMS fabric development in these shales units can provide insight into fluid flow processes. Panel_15164 Panel_15164 8:30 AM 5:00 PM

Mudrocks in the Eagle Ford Formation of South Texas are dominantly carls and argillaceous carls that represent mixtures of extrabasinal silicate detritus and intrabasinal carbonate grain assemblages containing both planktic and benthic carbonate allochems. There is also a significant component of biosiliceous debris in these mudrocks, much of which is extensively replaced. Close petrographic inspection of Eagle Ford lithologies reveals the local presence of sarls, dominated by massively calcitized radiolarian skeletons. Mobilization of silica by the replacement process is a likely cause of the precipitation of several forms of authigenic quartz, including microcrystalline allochem replacements, pore-filling quartz euhedra, and matrix-dispersed authigenic microquartz. Interestingly, little of this authigenic quartz is found associated with obvious radiolaria, suggesting considerable transport of the silica prior to precipitation. Cathodoluminescence imaging reveals that such authigenic quartz represents a large portion of the total quartz in the South Texas Eagle Ford Formation. Mudrocks in the Eagle Ford Formation of South Texas are dominantly carls and argillaceous carls that represent mixtures of extrabasinal silicate detritus and intrabasinal carbonate grain assemblages containing both planktic and benthic carbonate allochems. There is also a significant component of biosiliceous debris in these mudrocks, much of which is extensively replaced. Close petrographic inspection of Eagle Ford lithologies reveals the local presence of sarls, dominated by massively calcitized radiolarian skeletons. Mobilization of silica by the replacement process is a likely cause of the precipitation of several forms of authigenic quartz, including microcrystalline allochem replacements, pore-filling quartz euhedra, and matrix-dispersed authigenic microquartz. Interestingly, little of this authigenic quartz is found associated with obvious radiolaria, suggesting considerable transport of the silica prior to precipitation. Cathodoluminescence imaging reveals that such authigenic quartz represents a large portion of the total quartz in the South Texas Eagle Ford Formation. Panel_15161 Panel_15161 8:30 AM 5:00 PM

Panel_14464 Panel_14464 8:30 AM 5:00 PM

The Paleocene-Eocene Wilcox Group of onshore South Texas reaches a thickness of 1300 m, and contains a linked facies succession passing from coastal plain to shoreline to shelf and out to deepwater slope deposits. This spectrum of facies associations across Texas were the very deposits giving rise to the original concepts of ‘depositional systems’ by Fisher and McGowen (1967). A re-visit of some 500 wells and 1500 feet of cores through the Wilcox succession in South Texas shows that the fundamental organization of the linked facies tracts was one of some 24 transgressive(T) to regressive(R) units, thickening from av. 25 m on inner shelf to av. 75 m on outer shelf. Cores show that the transgressive part of units or sequences formed mainly from mixed energy, tidally-influenced estuaries, whereas the regressive part represents mainly river- and wave-dominated deltas. These fundamental sequences reflect the fact that the Wilcox shelf-margin prism was constructed by the repeated T-R transits of shorelines across the widening shelf, driven ultimately by northerly rivers. As successive T-R sequences accumulated, the shelf break of the clinoform system migrated up to 8 km basinward per sequence. To further evaluate the feeder river systems that drove the Wilcox shoreline, the Paleocene, Raton and Poison Canyon formations of the Laramide Raton Basin were examined, as these represent coeval fluvial systems that flowed southwards across New Mexico and Texas. The fluvial channels of the older Raton Formation are up to 6 times wider and up to 5 times deeper than the younger Poison Canyon channels. In addition, the former were more interconnected and sometimes sheet-like in their amalgamation, compared to the more isolate, lower net-to-gross channels of the Poison Canyon Formation. It is likely that the decreased sediment discharge through time in the Raton Basin reflects the change from coarser-grained Lower Wilcox to finer-grained Middle Wilcox on the GOM shelf-margin prism, and is also consistent with the recorded decrease in rates of shelf-margin progradation from Lower Wilcox (20-30 km/My) to Middle and Upper Wilcox (4-8 km/My). Although the large Raton channels and Wilcox distributary channels indicate Paleocene high sediment discharges to the coeval Gulf coast, the decreasing sediment discharge in late Paleocene and Eocene suggests lower Laramide relief generation and possibly northward diversion of some of the Laramide rivers. The Paleocene-Eocene Wilcox Group of onshore South Texas reaches a thickness of 1300 m, and contains a linked facies succession passing from coastal plain to shoreline to shelf and out to deepwater slope deposits. This spectrum of facies associations across Texas were the very deposits giving rise to the original concepts of ‘depositional systems’ by Fisher and McGowen (1967). A re-visit of some 500 wells and 1500 feet of cores through the Wilcox succession in South Texas shows that the fundamental organization of the linked facies tracts was one of some 24 transgressive(T) to regressive(R) units, thickening from av. 25 m on inner shelf to av. 75 m on outer shelf. Cores show that the transgressive part of units or sequences formed mainly from mixed energy, tidally-influenced estuaries, whereas the regressive part represents mainly river- and wave-dominated deltas. These fundamental sequences reflect the fact that the Wilcox shelf-margin prism was constructed by the repeated T-R transits of shorelines across the widening shelf, driven ultimately by northerly rivers. As successive T-R sequences accumulated, the shelf break of the clinoform system migrated up to 8 km basinward per sequence. To further evaluate the feeder river systems that drove the Wilcox shoreline, the Paleocene, Raton and Poison Canyon formations of the Laramide Raton Basin were examined, as these represent coeval fluvial systems that flowed southwards across New Mexico and Texas. The fluvial channels of the older Raton Formation are up to 6 times wider and up to 5 times deeper than the younger Poison Canyon channels. In addition, the former were more interconnected and sometimes sheet-like in their amalgamation, compared to the more isolate, lower net-to-gross channels of the Poison Canyon Formation. It is likely that the decreased sediment discharge through time in the Raton Basin reflects the change from coarser-grained Lower Wilcox to finer-grained Middle Wilcox on the GOM shelf-margin prism, and is also consistent with the recorded decrease in rates of shelf-margin progradation from Lower Wilcox (20-30 km/My) to Middle and Upper Wilcox (4-8 km/My). Although the large Raton channels and Wilcox distributary channels indicate Paleocene high sediment discharges to the coeval Gulf coast, the decreasing sediment discharge in late Paleocene and Eocene suggests lower Laramide relief generation and possibly northward diversion of some of the Laramide rivers. Panel_15280 Panel_15280 8:30 AM 5:00 PM

Growth styles of shelf-margin clinoforms are reliable but understudied predictors of Source-to Sink sand- and sediment-budget partitioning. Three discrete clinoform-growth styles were recognized, including strongly progradational clinoforms with low growth-trajectory angles (Gct), low aggradation/progradation ratios (A/P), low clinoform heights (Hc) and long clinoform length (Lc), mixed progradational and aggradational shelf-margin clinoforms are characterized by moderate Gct, moderate A/P, intermediate Hc and moderate Lc, and strongly aggradational clinoforms show high Gct, high A/P, high Hc and short Lc. In the South China Sea dataset considered, strongly progradational shelf-margin clinoforms exhibit flat progradational and at times a mildly aggrading stacking patterns, whereas mixed progradational and aggradational shelf-margin clinoforms display stacking patterns with significant progradation and aggradation . Strongly aggradational shelf-margin clinoforms are dominated by aggradational stacking patterns. Each clinoform-growth style therefore represents a specific stratal stacking pattern, providing an important tool for approaching a model-independent methodology in sequence stratigraphy. In the study dataset strongly progradational and strongly aggradational n clinoforms are fronted by sand-prone submarine fan systems with high sand-shale ratios and mud-dominated mass-transport systems with low sand-shale ratios, respectively. Mixed progradational and aggradational clinoforms are associated with mixed sand-mud submarine canyon systems with moderate sand-shale ratios. Additionally, strongly progradational shelf-margin clinoforms partitioned great volumes of sediment into deep-water areas, as reflected by high rates of shelf-edge progradation. Strongly aggradational clinoforms, in contrast, stored great volumes of sediment on the shelf itself, as indicated by high rates of shelf-edge aggradation and very thick clinoform topsets. Gct and Hc therefore increase linearly with sediment volumes partitioned into shelf margins, but decrease linearly with sand- and sediment-budget partitioning into deep-water areas, given a constant supply condition. Clinoforms growth styles are thus good predictors of sand- and sediment-volume partitioning into and across shelf margins, assisting greatly in developing a more dynamic stratigraphy. Growth styles of shelf-margin clinoforms are reliable but understudied predictors of Source-to Sink sand- and sediment-budget partitioning. Three discrete clinoform-growth styles were recognized, including strongly progradational clinoforms with low growth-trajectory angles (Gct), low aggradation/progradation ratios (A/P), low clinoform heights (Hc) and long clinoform length (Lc), mixed progradational and aggradational shelf-margin clinoforms are characterized by moderate Gct, moderate A/P, intermediate Hc and moderate Lc, and strongly aggradational clinoforms show high Gct, high A/P, high Hc and short Lc. In the South China Sea dataset considered, strongly progradational shelf-margin clinoforms exhibit flat progradational and at times a mildly aggrading stacking patterns, whereas mixed progradational and aggradational shelf-margin clinoforms display stacking patterns with significant progradation and aggradation . Strongly aggradational shelf-margin clinoforms are dominated by aggradational stacking patterns. Each clinoform-growth style therefore represents a specific stratal stacking pattern, providing an important tool for approaching a model-independent methodology in sequence stratigraphy. In the study dataset strongly progradational and strongly aggradational n clinoforms are fronted by sand-prone submarine fan systems with high sand-shale ratios and mud-dominated mass-transport systems with low sand-shale ratios, respectively. Mixed progradational and aggradational clinoforms are associated with mixed sand-mud submarine canyon systems with moderate sand-shale ratios. Additionally, strongly progradational shelf-margin clinoforms partitioned great volumes of sediment into deep-water areas, as reflected by high rates of shelf-edge progradation. Strongly aggradational clinoforms, in contrast, stored great volumes of sediment on the shelf itself, as indicated by high rates of shelf-edge aggradation and very thick clinoform topsets. Gct and Hc therefore increase linearly with sediment volumes partitioned into shelf margins, but decrease linearly with sand- and sediment-budget partitioning into deep-water areas, given a constant supply condition. Clinoforms growth styles are thus good predictors of sand- and sediment-volume partitioning into and across shelf margins, assisting greatly in developing a more dynamic stratigraphy. Panel_15286 Panel_15286 8:30 AM 5:00 PM

While the provenance of modern sands delivered to the Gulf of Mexico by the Mississippi is well studied using heavy mineral analysis, scant attention is placed on what insights can be gained from the lighter components of sands. Although proven to detect broad source domains, heavy minerals grains such as zircon can suffer from a number of drawbacks including recycling and non-uniqueness. Conversely, the monocyclic nature of K-feldspar and its modal abundance in sands means K-feldspar grains are more uniquely representative fingerprints of their source rock(s). The association of K-feldspar and quartz particularly in granitoid rocks also mean that it can act as a proxy for the source of at least some of the quartz grains. In addition, only small sample sizes are required as sands and source rocks can be characterised using relatively few grains. A preliminary study shows that the Pb in K-feldspar technique is effective in detecting distinct Pb populations within modern sands of the Mississippi and its tributaries. In order to re-evaluate the provenance of modern river sands on a spatially representative scale, common Pb isotopes in detrital K-feldspars are characterised by LA-MC-ICPMS in over 40 samples collected across the Mississippi drainage basin. Tributaries including the Arkansas, Red, Platte, Missouri, and Ohio Rivers are also sampled in an attempt to evaluate the contribution from each tributary and understand the effect, if any, of dilution and mixing of detrital grain populations. A number of samples are also examined from coastal plain rivers draining into the Gulf of Mexico to determine if diagnostic Pb signatures are present. Understanding the provenance of sands delivered by the Mississippi system has significant implications for the evolution of the drainage basin. By investigating the contributions from different areas within the catchment we can gain a greater understanding of sediment pathways and the processes which govern the supply of sediment to the offshore. In this way, this research has important implications for the distribution and quality of reservoir sands within the Gulf of Mexico. Furthermore, as the Pb in K-feldspar technique has not yet been applied at this spatial resolution to a modern continental-scale drainage basin, this study affords the opportunity to evaluate the Pb in K-feldspar technique and uncover what insights it can offer over, and in combination with, more conventional provenance markers. While the provenance of modern sands delivered to the Gulf of Mexico by the Mississippi is well studied using heavy mineral analysis, scant attention is placed on what insights can be gained from the lighter components of sands. Although proven to detect broad source domains, heavy minerals grains such as zircon can suffer from a number of drawbacks including recycling and non-uniqueness. Conversely, the monocyclic nature of K-feldspar and its modal abundance in sands means K-feldspar grains are more uniquely representative fingerprints of their source rock(s). The association of K-feldspar and quartz particularly in granitoid rocks also mean that it can act as a proxy for the source of at least some of the quartz grains. In addition, only small sample sizes are required as sands and source rocks can be characterised using relatively few grains. A preliminary study shows that the Pb in K-feldspar technique is effective in detecting distinct Pb populations within modern sands of the Mississippi and its tributaries. In order to re-evaluate the provenance of modern river sands on a spatially representative scale, common Pb isotopes in detrital K-feldspars are characterised by LA-MC-ICPMS in over 40 samples collected across the Mississippi drainage basin. Tributaries including the Arkansas, Red, Platte, Missouri, and Ohio Rivers are also sampled in an attempt to evaluate the contribution from each tributary and understand the effect, if any, of dilution and mixing of detrital grain populations. A number of samples are also examined from coastal plain rivers draining into the Gulf of Mexico to determine if diagnostic Pb signatures are present. Understanding the provenance of sands delivered by the Mississippi system has significant implications for the evolution of the drainage basin. By investigating the contributions from different areas within the catchment we can gain a greater understanding of sediment pathways and the processes which govern the supply of sediment to the offshore. In this way, this research has important implications for the distribution and quality of reservoir sands within the Gulf of Mexico. Furthermore, as the Pb in K-feldspar technique has not yet been applied at this spatial resolution to a modern continental-scale drainage basin, this study affords the opportunity to evaluate the Pb in K-feldspar technique and uncover what insights it can offer over, and in combination with, more conventional provenance markers. Panel_15285 Panel_15285 8:30 AM 5:00 PM

A quantitative measurement of sediment supply derived from stratigraphy is an elusive goal, but realization could provide the opportunity to elucidate dynamic interactions between sediment supply and other basin dynamics. To this end, we address the question of how changes in sediment supply influence stratigraphic patterns using cosmogenic nuclides to calculate paleo-denudation rates (a proxy for sediment supply) feeding a catchment-fan system. The Pleistocene Pleasant Canyon fan complex emanates from the west flank of the Panamint Mountains, Inyo County, California, and is exposed in a ~200 m-thick and 2 km-wide outcrop of mixed alluvial fan-lacustrine stratigraphy. Several cycles are preserved within the succession, defined by changes in dominant grain size, sedimentary structures, and a repeating motif of lacustrine marl-to-gravel transitions. Sedimentological interpretations indicate cycles represent catchment-fan system response to lacustrine fill-desiccation cycles, with marl deposits representing lake highstands. Synsedimentary normal faults are documented but likely account for minor changes in accommodation relative to abrupt lake level changes. Paleo-sediment flux estimates could disentangle sediment supply variability from base-level changes during glacial-interglacial cycles. A detailed stratigraphic framework and cosmogenic nuclide sample suite allows us to construct a depositional model incorporating age determinations derived from paired isotope measurements (26Al/10Be) yielding aggradation rates and ultimately paleo-sediment flux. A quantitative measurement of sediment supply derived from stratigraphy is an elusive goal, but realization could provide the opportunity to elucidate dynamic interactions between sediment supply and other basin dynamics. To this end, we address the question of how changes in sediment supply influence stratigraphic patterns using cosmogenic nuclides to calculate paleo-denudation rates (a proxy for sediment supply) feeding a catchment-fan system. The Pleistocene Pleasant Canyon fan complex emanates from the west flank of the Panamint Mountains, Inyo County, California, and is exposed in a ~200 m-thick and 2 km-wide outcrop of mixed alluvial fan-lacustrine stratigraphy. Several cycles are preserved within the succession, defined by changes in dominant grain size, sedimentary structures, and a repeating motif of lacustrine marl-to-gravel transitions. Sedimentological interpretations indicate cycles represent catchment-fan system response to lacustrine fill-desiccation cycles, with marl deposits representing lake highstands. Synsedimentary normal faults are documented but likely account for minor changes in accommodation relative to abrupt lake level changes. Paleo-sediment flux estimates could disentangle sediment supply variability from base-level changes during glacial-interglacial cycles. A detailed stratigraphic framework and cosmogenic nuclide sample suite allows us to construct a depositional model incorporating age determinations derived from paired isotope measurements (26Al/10Be) yielding aggradation rates and ultimately paleo-sediment flux. Panel_15282 Panel_15282 8:30 AM 5:00 PM

Tectonics is very important to the depositional record preserved in nonmarine sedimentary basins. Tanan Sub-basin is a Lower Cretaceous active-fault bounded basin in Mongolia. Episodic rifting, differential subsidence both along the boundary fault strike and across the basin, resulted in the formation of distinct paleogeomorphology, including various types of transfer zones and fault-break zones. In this study, the control of paleogeomorphology to the spatial distribution and temporal evolution of depositional systems and sand bodies in Tanan Sub-basin were investigated using seismic profiles, cores and well logs. Transfer zones could be subdivided into two types according to the various displacement along the fault strike and the related topographies. They were synthetic approaching transfer zones characterized by the topography of transverse uplifts and synthetic overlapping transfer zones characterized by the topography of relay ramps. Transfer zones controlled the locations of sedimentary provenances, entry points for sediments into the basin, and as a result, the development of depositional systems. The large-scale, coarse grained sandstone/conglomerate of fan deltas are mainly deposited in the transfer zones, in contract, small-scale, fine grained sandstone deposited in other positions along the fault strike. According to fault geometry and the location, four fault-break zones and related depositional systems were identified. They were fault-scarp zones controlling the development of fan-deltas and nearshore sublacustrine, fault-terrace zones controlling the development of fan-deltas and offshore sublacustrine fans, half-graben dip-slope zones controlling the development of braided river and braided deltas, and intra-basinal fault-break zones controlling the development of offshore sublacustrine fans. The fault-break zones mainly influenced the distribution of depositional systems and sand bodies. Areas where the fault-break zone overlapped with transfer zones were sites for major drainage systems and the optimum locations of fan deltas and sublacustrine fans. The sand bodies were mainly accumulated at the lower part of fault-break zones, and the rift-interior sediment dispersal directions are consistent with the strike of the fault-break zone. Due to interbedded with deep lacustrine mudstone, sand bodies deposited here are favorable targets for the prospecting of litho-stratigraphic traps in Tanan sub-basin. Tectonics is very important to the depositional record preserved in nonmarine sedimentary basins. Tanan Sub-basin is a Lower Cretaceous active-fault bounded basin in Mongolia. Episodic rifting, differential subsidence both along the boundary fault strike and across the basin, resulted in the formation of distinct paleogeomorphology, including various types of transfer zones and fault-break zones. In this study, the control of paleogeomorphology to the spatial distribution and temporal evolution of depositional systems and sand bodies in Tanan Sub-basin were investigated using seismic profiles, cores and well logs. Transfer zones could be subdivided into two types according to the various displacement along the fault strike and the related topographies. They were synthetic approaching transfer zones characterized by the topography of transverse uplifts and synthetic overlapping transfer zones characterized by the topography of relay ramps. Transfer zones controlled the locations of sedimentary provenances, entry points for sediments into the basin, and as a result, the development of depositional systems. The large-scale, coarse grained sandstone/conglomerate of fan deltas are mainly deposited in the transfer zones, in contract, small-scale, fine grained sandstone deposited in other positions along the fault strike. According to fault geometry and the location, four fault-break zones and related depositional systems were identified. They were fault-scarp zones controlling the development of fan-deltas and nearshore sublacustrine, fault-terrace zones controlling the development of fan-deltas and offshore sublacustrine fans, half-graben dip-slope zones controlling the development of braided river and braided deltas, and intra-basinal fault-break zones controlling the development of offshore sublacustrine fans. The fault-break zones mainly influenced the distribution of depositional systems and sand bodies. Areas where the fault-break zone overlapped with transfer zones were sites for major drainage systems and the optimum locations of fan deltas and sublacustrine fans. The sand bodies were mainly accumulated at the lower part of fault-break zones, and the rift-interior sediment dispersal directions are consistent with the strike of the fault-break zone. Due to interbedded with deep lacustrine mudstone, sand bodies deposited here are favorable targets for the prospecting of litho-stratigraphic traps in Tanan sub-basin. Panel_15284 Panel_15284 8:30 AM 5:00 PM

Trinidad is an uplifted segment of the Orinoco Neogene shelf. The Atlantic-facing shelf-margin sediment prism has an internal clinoform architecture, with both sandy marine topsets and muddy deepwater slope deposits with turbidite channels and collapsed shelf blocks. The shelf prism is several km thick and >200km wide, built from late Miocene to present. The shelf-margin had an irregularly rising trajectory with very thick topset aggradation and rapid progradation of the fronting deepwater slope. High sediment supply (18-33km/My progradation rate) and exceptionally high shelf-subsidence rates (up to 600m/My) led to prominent sand bypass from shelf into deepwater areas. Trinidad outcrops expose the proximal half of this sediment prism including Miocene deepwater strata. Cruse Fm. outcrops expose 10s of km in a downdip (shelf to basin) direction from west to east along southern Trinidad. This outcrop distribution allows the shelf-break position to be identified, separating a western shelf and shelf-edge delta segment from an eastern highly deformed segment with very large (house size) blocks of shallow-water facies that are disoriented and embedded in deformed mudstones. Below the shelf break, the facies are mainly very fine sandstone shelf-edge collapse blocks, as well as turbidite-filled slope channels and slope mudstones. Most of the sandstone blocks and associated chaotic beds contain highly deformed parallel-laminated and hummocky cross strata. Landward of the shelf-edge area, the facies are mainly stacked parasequences of undeformed, upward-coarsening shelf-edge delta deposits (3-15m thick), in places sharply truncating (toplap) the slope mudstones and mass transport deposits. The great thickness and downcutting of most of the topset channels and the repeated transits of the 30-40m thick delta cycles may indicate forced regressive deltas that were driven across the shelf by falling relative sea level at this time. The facies architectures, both vertically and laterally (from distal to proximal) provide two hypotheses for the Cruse Fm. clinoform sets morphology as well as facies patterns: (1) a simple rising trajectory with upward-growing clinoforms, or (2) a rising and then flat (forced regressive) trajectory combination. The Cruse Fm. clinoform sets record not only the position of the growing shelf edge, but also provide a quantitative indicator that up to two-thirds of the total sediment flux budget was by-passing the shelf edge into deepwater areas. Trinidad is an uplifted segment of the Orinoco Neogene shelf. The Atlantic-facing shelf-margin sediment prism has an internal clinoform architecture, with both sandy marine topsets and muddy deepwater slope deposits with turbidite channels and collapsed shelf blocks. The shelf prism is several km thick and >200km wide, built from late Miocene to present. The shelf-margin had an irregularly rising trajectory with very thick topset aggradation and rapid progradation of the fronting deepwater slope. High sediment supply (18-33km/My progradation rate) and exceptionally high shelf-subsidence rates (up to 600m/My) led to prominent sand bypass from shelf into deepwater areas. Trinidad outcrops expose the proximal half of this sediment prism including Miocene deepwater strata. Cruse Fm. outcrops expose 10s of km in a downdip (shelf to basin) direction from west to east along southern Trinidad. This outcrop distribution allows the shelf-break position to be identified, separating a western shelf and shelf-edge delta segment from an eastern highly deformed segment with very large (house size) blocks of shallow-water facies that are disoriented and embedded in deformed mudstones. Below the shelf break, the facies are mainly very fine sandstone shelf-edge collapse blocks, as well as turbidite-filled slope channels and slope mudstones. Most of the sandstone blocks and associated chaotic beds contain highly deformed parallel-laminated and hummocky cross strata. Landward of the shelf-edge area, the facies are mainly stacked parasequences of undeformed, upward-coarsening shelf-edge delta deposits (3-15m thick), in places sharply truncating (toplap) the slope mudstones and mass transport deposits. The great thickness and downcutting of most of the topset channels and the repeated transits of the 30-40m thick delta cycles may indicate forced regressive deltas that were driven across the shelf by falling relative sea level at this time. The facies architectures, both vertically and laterally (from distal to proximal) provide two hypotheses for the Cruse Fm. clinoform sets morphology as well as facies patterns: (1) a simple rising trajectory with upward-growing clinoforms, or (2) a rising and then flat (forced regressive) trajectory combination. The Cruse Fm. clinoform sets record not only the position of the growing shelf edge, but also provide a quantitative indicator that up to two-thirds of the total sediment flux budget was by-passing the shelf edge into deepwater areas. Panel_15289 Panel_15289 8:30 AM 5:00 PM

Collision between Laurentia and Gondwana and intervening terranes had terminated the passive margin continental slope sedimentation and formed the Ouachita Orogen and related foreland basins in the southern mid-continent during the Paleozoic. Multiple Paleozoic age clastic rocks are cropped along the southwest Missouri, northeast Oklahoma, and northwest Arkansas. Different models, including local vs. long distance transported, have been proposed to interpret the sources of those clastic rocks. In this study, a series of Ordovician to Pennsylvanian age sandstones were sampled from outcrops. LA-ICP-MS U-Pb detrital zircon geochronology was utilized to constrain sediment sources and dispersal patterns. In total 20 samples and 1300 single detrital zircon grains were analyzed. Results show that there are five distinct age groups, including 0.4-0.6 Ga, 1.0-1.2 Ga, 1.3-1.5 Ga, 1.6-1.8 Ga, and >2.5 Ga. Regional source terranes correlation suggest that the oldest group (>2.5 Ga) is attributed to the Superior Province of the Canadian Shield; the 1.6-1.8 Ga group corresponds well with Yavapai-Mazatzal provinces; the 1.3-1.5 Ga group is not tightly constrained, but may originate from a localized midcontinent source, such as the Ozark Dome; the 0.4-0.6 Ga group is believed to have originated from Acadian and Taconic Orogenies; and the 1.0-1.2 Ga range is mostly likely derived from the Grenville crystalline rocks. The Ordovician sandstones are characterized by older age groups (older than 1.0 Ga) and were interpreted as mainly recycled sources originated from the Canadian Shield. All post-Ordovician sandstones show mixed source signatures. In addition to the older age groups, 0.4-0.6 Ga age group became another primary source. In contrast to previous model, provenance change started in the Early Mississippian. All Mississippian and Pennsylvanian sandstones share same sources, either directly derived from craton and/or recycled from previous sediments source to the north and northeast. Collision between Laurentia and Gondwana and intervening terranes had terminated the passive margin continental slope sedimentation and formed the Ouachita Orogen and related foreland basins in the southern mid-continent during the Paleozoic. Multiple Paleozoic age clastic rocks are cropped along the southwest Missouri, northeast Oklahoma, and northwest Arkansas. Different models, including local vs. long distance transported, have been proposed to interpret the sources of those clastic rocks. In this study, a series of Ordovician to Pennsylvanian age sandstones were sampled from outcrops. LA-ICP-MS U-Pb detrital zircon geochronology was utilized to constrain sediment sources and dispersal patterns. In total 20 samples and 1300 single detrital zircon grains were analyzed. Results show that there are five distinct age groups, including 0.4-0.6 Ga, 1.0-1.2 Ga, 1.3-1.5 Ga, 1.6-1.8 Ga, and >2.5 Ga. Regional source terranes correlation suggest that the oldest group (>2.5 Ga) is attributed to the Superior Province of the Canadian Shield; the 1.6-1.8 Ga group corresponds well with Yavapai-Mazatzal provinces; the 1.3-1.5 Ga group is not tightly constrained, but may originate from a localized midcontinent source, such as the Ozark Dome; the 0.4-0.6 Ga group is believed to have originated from Acadian and Taconic Orogenies; and the 1.0-1.2 Ga range is mostly likely derived from the Grenville crystalline rocks. The Ordovician sandstones are characterized by older age groups (older than 1.0 Ga) and were interpreted as mainly recycled sources originated from the Canadian Shield. All post-Ordovician sandstones show mixed source signatures. In addition to the older age groups, 0.4-0.6 Ga age group became another primary source. In contrast to previous model, provenance change started in the Early Mississippian. All Mississippian and Pennsylvanian sandstones share same sources, either directly derived from craton and/or recycled from previous sediments source to the north and northeast. Panel_15288 Panel_15288 8:30 AM 5:00 PM

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Panel_14470 Panel_14470 8:30 AM 5:00 PM

The mechanical stratigraphy of the Upper Ordovician Utica Shale is characterized by studying outcrops and core from Montgomery County in eastern New York State. Previous studies of the Utica Shale in New York State have focused on characterizing fracture orientations, distinguishing fracture generations, and establishing a relationship between fracture density and proximity to faults, but fractures in outcrops of the Utica Shale have not been studied in the context of mechanical stratigraphy. The composition, sedimentary texture, strength, and thickness of individual beds within the Flat Creek Shale and Dolgeville Formation are studied to better understand the nature of fracture propagation in relatively thinly-bedded mudrocks. The Flat Creek Shale and Dolgeville Formation are fine-grained siliciclastics containing varying amounts of detrital carbonate grains. There are also multiple bentonites within both members. A fracture bedding termination analysis is conducted at three outcrops of the Flat Creek Shale to identify mechanical interfaces. A Schmidt Hammer is used to measure rock strengths approximately every .2 vertical meters of the outcrop section being studied. Additionally, samples are collected throughout the vertical section to be analyzed by XRD. Utica Core 74 NY-5 is described in terms of bedding thicknesses, lithofacies, and sedimentary texture. Three thin sections are analyzed with petrographic microscopes to identify common textures and mechanical flaws associated with individual lithofacies. The combination of the fracture bedding termination analysis, rock strength measurement, core description, petrographic investigation, and XRD analysis assist with characterizing the mechanical behavior of these rocks. The fracture bedding termination analysis indicates that bentonites are responsible for approximately 51% of identifiable fracture terminations; therefore bentonites act as mechanical barriers to fracture propagation. The bentonites exhibit significantly lower present day rock strength values and are likely primarily composed of clays. While the remaining 49% of vein-filled fracture terminations occur elsewhere, there are few shale mechanical interfaces identified. Our observation that bentonite horizons form significant mechanical barriers to fracture propagation has important implications for modeling subsurface fracture networks because bentonites are widespread in this and other basins, and are easily distinguished on gamma ray logs. The mechanical stratigraphy of the Upper Ordovician Utica Shale is characterized by studying outcrops and core from Montgomery County in eastern New York State. Previous studies of the Utica Shale in New York State have focused on characterizing fracture orientations, distinguishing fracture generations, and establishing a relationship between fracture density and proximity to faults, but fractures in outcrops of the Utica Shale have not been studied in the context of mechanical stratigraphy. The composition, sedimentary texture, strength, and thickness of individual beds within the Flat Creek Shale and Dolgeville Formation are studied to better understand the nature of fracture propagation in relatively thinly-bedded mudrocks. The Flat Creek Shale and Dolgeville Formation are fine-grained siliciclastics containing varying amounts of detrital carbonate grains. There are also multiple bentonites within both members. A fracture bedding termination analysis is conducted at three outcrops of the Flat Creek Shale to identify mechanical interfaces. A Schmidt Hammer is used to measure rock strengths approximately every .2 vertical meters of the outcrop section being studied. Additionally, samples are collected throughout the vertical section to be analyzed by XRD. Utica Core 74 NY-5 is described in terms of bedding thicknesses, lithofacies, and sedimentary texture. Three thin sections are analyzed with petrographic microscopes to identify common textures and mechanical flaws associated with individual lithofacies. The combination of the fracture bedding termination analysis, rock strength measurement, core description, petrographic investigation, and XRD analysis assist with characterizing the mechanical behavior of these rocks. The fracture bedding termination analysis indicates that bentonites are responsible for approximately 51% of identifiable fracture terminations; therefore bentonites act as mechanical barriers to fracture propagation. The bentonites exhibit significantly lower present day rock strength values and are likely primarily composed of clays. While the remaining 49% of vein-filled fracture terminations occur elsewhere, there are few shale mechanical interfaces identified. Our observation that bentonite horizons form significant mechanical barriers to fracture propagation has important implications for modeling subsurface fracture networks because bentonites are widespread in this and other basins, and are easily distinguished on gamma ray logs. Panel_15339 Panel_15339 8:30 AM 5:00 PM

Detailed analysis of natural fracture network geometry is an important step in the geomechanical modelling and characterization of unconventional tight reservoirs as fractures provide flow pathways for hydrocarbons and other fluids in the subsurface as well as influence hydraulically induced fracture development. Characterizing subsurface fractures is challenging since boreholes provide a limited view, but outcrops provide useful 3D subsurface analogs. Exposed outcrops of the Second White Specks Formation along the Highwood River in southwestern Alberta were divided into three major facies: 1) the Jumping Pound Sandstone; 2) interbedded finely laminated siltstones and mudstones; and 3) black organic-rich mudstone. Natural fracture parameters were recorded from each facies interval using scanlines and additionally using the circular estimator method on the bedding plane of the Jumping Pound Sandstone. Results from the sampling methods were used to compare the relative differences in natural fracture characteristics between sedimentary facies in the Second White Specks Formation. The Jumping Pound Sandstone contains compressional conjugate shear fractures that occur at relatively low intensity (2.56–4.7 fractures per meter) with relatively tall heights (0.79–3.38 meters). The interbedded finely laminated siltstones and mudstones contain extensional fractures that occur at relatively high intensity (29.2 fractures per meter) with relatively short heights (0.18 meters), the latter being related to the finely interlaminated siltstone-mudstone fabric. The black organic-rich mudstone contains fractures that are conjugate to the underlying thrust fault in addition to extensional fractures that both occur at relatively low intensity (4.88–7.4 fractures per meter) with relatively tall heights (1.18–1.25 meters). Elevated fluid pressures resulting from hydrocarbon generation within the two mudstone facies could have altered the stress field in such a way that promoted the formation of extensional fractures compared to the compressional shear fractures that occur in the overlying Jumping Pound Sandstone. The results from this analysis suggest that sedimentary facies characteristics such as lithology, heterogeneity and mechanical bed thickness have a strong influence on fracture generation and propagation in the Second White Specks Formation outcrops along the Highwood River that are also likely to be present in the subsurface. Detailed analysis of natural fracture network geometry is an important step in the geomechanical modelling and characterization of unconventional tight reservoirs as fractures provide flow pathways for hydrocarbons and other fluids in the subsurface as well as influence hydraulically induced fracture development. Characterizing subsurface fractures is challenging since boreholes provide a limited view, but outcrops provide useful 3D subsurface analogs. Exposed outcrops of the Second White Specks Formation along the Highwood River in southwestern Alberta were divided into three major facies: 1) the Jumping Pound Sandstone; 2) interbedded finely laminated siltstones and mudstones; and 3) black organic-rich mudstone. Natural fracture parameters were recorded from each facies interval using scanlines and additionally using the circular estimator method on the bedding plane of the Jumping Pound Sandstone. Results from the sampling methods were used to compare the relative differences in natural fracture characteristics between sedimentary facies in the Second White Specks Formation. The Jumping Pound Sandstone contains compressional conjugate shear fractures that occur at relatively low intensity (2.56–4.7 fractures per meter) with relatively tall heights (0.79–3.38 meters). The interbedded finely laminated siltstones and mudstones contain extensional fractures that occur at relatively high intensity (29.2 fractures per meter) with relatively short heights (0.18 meters), the latter being related to the finely interlaminated siltstone-mudstone fabric. The black organic-rich mudstone contains fractures that are conjugate to the underlying thrust fault in addition to extensional fractures that both occur at relatively low intensity (4.88–7.4 fractures per meter) with relatively tall heights (1.18–1.25 meters). Elevated fluid pressures resulting from hydrocarbon generation within the two mudstone facies could have altered the stress field in such a way that promoted the formation of extensional fractures compared to the compressional shear fractures that occur in the overlying Jumping Pound Sandstone. The results from this analysis suggest that sedimentary facies characteristics such as lithology, heterogeneity and mechanical bed thickness have a strong influence on fracture generation and propagation in the Second White Specks Formation outcrops along the Highwood River that are also likely to be present in the subsurface. Panel_15341 Panel_15341 8:30 AM 5:00 PM

The performance of unconventional mudstone reservoirs is in large part a function of the mechanical properties of the mudstone. Mechanical properties (yield and failure strength, nonlinear elasticity, anisotropy, etc.) are controlled by a variety of geologic variables, including detrital and authigenic mineralogy including cements, organic content, and the spatial distribution of these characteristics (i.e., heterogeneity). We are investigating impact of these lithologic controls across a wide range of scales for a common lithofacies of Cretaceous Mancos Shale. We map lithologic characteristics at different scales using a variety of techniques. Mudstone core samples are first subdivided into principal macroscopic lithofacies. Samples of the macroscopic lithofacies were further characterized petrographically, and microscopic facies identified using laser confocal microscopy to map the abundance, size, and spatial distribution of porosity, kerogen, and mineralogy. Mudstone mechanical properties were measured at a range of scales, including seismic wave velocity (Vp, Vs) and creep data for cm-sized samples, and nanoindentation measurements of focused ion-beam milled pillars. Our goal is to allow more accurate prediction of reservoir performance by developing a multi-scale understanding of mudstone response to reservoir stimulation efforts. The performance of unconventional mudstone reservoirs is in large part a function of the mechanical properties of the mudstone. Mechanical properties (yield and failure strength, nonlinear elasticity, anisotropy, etc.) are controlled by a variety of geologic variables, including detrital and authigenic mineralogy including cements, organic content, and the spatial distribution of these characteristics (i.e., heterogeneity). We are investigating impact of these lithologic controls across a wide range of scales for a common lithofacies of Cretaceous Mancos Shale. We map lithologic characteristics at different scales using a variety of techniques. Mudstone core samples are first subdivided into principal macroscopic lithofacies. Samples of the macroscopic lithofacies were further characterized petrographically, and microscopic facies identified using laser confocal microscopy to map the abundance, size, and spatial distribution of porosity, kerogen, and mineralogy. Mudstone mechanical properties were measured at a range of scales, including seismic wave velocity (Vp, Vs) and creep data for cm-sized samples, and nanoindentation measurements of focused ion-beam milled pillars. Our goal is to allow more accurate prediction of reservoir performance by developing a multi-scale understanding of mudstone response to reservoir stimulation efforts. Panel_15337 Panel_15337 8:30 AM 5:00 PM

Natural fracture pathways are a critical component of unconventional hydrocarbon plays. A unique challenge is examining these fracture networks to gain key insights into the connectivity and potential migration pathways of a reservoir. Fracture networks should be considered in conjunction with the varying mechanical properties of the stratigraphy and the regional and local stress regimes. The Ozark Plateau is an ideal study area for fracture research, since the stratigraphy of the area is similar to major onshore carbonate reservoirs currently being exploited, notably the Miss. Lime play, where fractures play a large role in reservoir permeability. In addition, Ozark Plateau fracture networks are the product of several fracturing events from the multi-stage Ouachita Orogeny during the late Paleozoic. This study used field observations of lithology, fracture attributes and hardness data over 17 outcrops in the Mississippian (360-323 Ma) carbonate sequence in Missouri and Arkansas. Outcrops were chosen to give extensive data through the St. Joe to Boone Formations and in areas where there were 3D representations of the fracture patterns. Fracture attributes collected included orientation, intensity, length, and abutting relationships. Rock hardness data were collected from in-situ outcrop samples using a rebound hammer. 34 thin sections were prepared for the description and analysis of all major lithologies observed. Initial results indicate 4 main fracture orientations that resulted from at least 3 discrete phases of deformation during the Miss-Penn. Two primary sets strike NE-SW and NW-SE and appear through most of the sequence. Secondary sets are oriented E-W and NNW-SSE and the presence of these sets may be controlled by mechanical or diagenetic factors. However, present-day mechanical stratigraphy apparently differs from that during the deformation phases, as some fracture sets do not show a relationship to either bed boundaries or the differences in mechanical properties. This study suggests that fractures related to the main regional stress direction can overcome variation in mechanical properties, while fractures forming under local stress perturbations are more sensitive to mechanical and diagenetic changes. Fully characterizing naturally fractured reservoirs requires a detailed analysis of the interplay between regional stress regimes and local variation in mechanical properties. Natural fracture pathways are a critical component of unconventional hydrocarbon plays. A unique challenge is examining these fracture networks to gain key insights into the connectivity and potential migration pathways of a reservoir. Fracture networks should be considered in conjunction with the varying mechanical properties of the stratigraphy and the regional and local stress regimes. The Ozark Plateau is an ideal study area for fracture research, since the stratigraphy of the area is similar to major onshore carbonate reservoirs currently being exploited, notably the Miss. Lime play, where fractures play a large role in reservoir permeability. In addition, Ozark Plateau fracture networks are the product of several fracturing events from the multi-stage Ouachita Orogeny during the late Paleozoic. This study used field observations of lithology, fracture attributes and hardness data over 17 outcrops in the Mississippian (360-323 Ma) carbonate sequence in Missouri and Arkansas. Outcrops were chosen to give extensive data through the St. Joe to Boone Formations and in areas where there were 3D representations of the fracture patterns. Fracture attributes collected included orientation, intensity, length, and abutting relationships. Rock hardness data were collected from in-situ outcrop samples using a rebound hammer. 34 thin sections were prepared for the description and analysis of all major lithologies observed. Initial results indicate 4 main fracture orientations that resulted from at least 3 discrete phases of deformation during the Miss-Penn. Two primary sets strike NE-SW and NW-SE and appear through most of the sequence. Secondary sets are oriented E-W and NNW-SSE and the presence of these sets may be controlled by mechanical or diagenetic factors. However, present-day mechanical stratigraphy apparently differs from that during the deformation phases, as some fracture sets do not show a relationship to either bed boundaries or the differences in mechanical properties. This study suggests that fractures related to the main regional stress direction can overcome variation in mechanical properties, while fractures forming under local stress perturbations are more sensitive to mechanical and diagenetic changes. Fully characterizing naturally fractured reservoirs requires a detailed analysis of the interplay between regional stress regimes and local variation in mechanical properties. Panel_15340 Panel_15340 8:30 AM 5:00 PM

Unconventional resources such as tight sands, shales and coal seam gas reservoirs are defined by low matrix permeability. Economic production of these reservoirs relies on natural fracture networks and hydraulic fracture stimulation to enhance reservoir permeability. Seismic curvature analysis is commonly used to identify areas of higher natural fracture density and regions of lower horizontal stress; stress condition is a key success factor in hydraulic fracture stimulation treatments. This study uses geomechanical models to interrogate traditional assumptions of curvature and stress distribution in extensional and compressional tectonic settings. It is an oversimplification to assume that anticlines have favourable curvature and synclines have unfavourable curvature. A more realistic view of these structural features considers the sum of multiple phenomena: bending beam forces, overburden force, the Poisson’s ratio effect, the arch effect, friction between lithological layers and regional tectonic forces. (1) Bending beam theory states that beams will be in compression inside the ‘neutral surface’ and in extension outside the neutral surface. (2) Weight of the overburden is self-explanatory and generates the vertical stress. (3) Poisson’s ratio effect will convert vertical stress into horizontal stress. (4) Arch effect of an anticline/syncline will lessen vertical stress and increase horizontal stress. Paradoxically, the lessened vertical stress translates (via the Poisson’s ratio effect) to lowered horizontal stress. (5) Friction between lithological layers can suppress the bending beam effect. (6) Regional tectonic forces can influence horizontal stress and the arch effect. Models presented here are generated with the poro-elastic equation and with ABAQUS, a 2D/3D finite-element simulator that incorporates stress-strain relationships, gravity, pore pressure, far field (tectonic) stress and rock mechanical properties. We calculate vertical and horizontal stress distribution through three lithological layers and across a structural high. Results challenge common assumptions of seismic curvature: they show low stress sweet spots occur not only at the crest of an anticline but on the flanks too, and horizontal stress may be increasing or decreasing with depth, depending on lithology type and bounding layers. This study argues that traditional conclusions from curvature analysis should be scrutinised more closely, especially in application to unconventional reservoirs. Unconventional resources such as tight sands, shales and coal seam gas reservoirs are defined by low matrix permeability. Economic production of these reservoirs relies on natural fracture networks and hydraulic fracture stimulation to enhance reservoir permeability. Seismic curvature analysis is commonly used to identify areas of higher natural fracture density and regions of lower horizontal stress; stress condition is a key success factor in hydraulic fracture stimulation treatments. This study uses geomechanical models to interrogate traditional assumptions of curvature and stress distribution in extensional and compressional tectonic settings. It is an oversimplification to assume that anticlines have favourable curvature and synclines have unfavourable curvature. A more realistic view of these structural features considers the sum of multiple phenomena: bending beam forces, overburden force, the Poisson’s ratio effect, the arch effect, friction between lithological layers and regional tectonic forces. (1) Bending beam theory states that beams will be in compression inside the ‘neutral surface’ and in extension outside the neutral surface. (2) Weight of the overburden is self-explanatory and generates the vertical stress. (3) Poisson’s ratio effect will convert vertical stress into horizontal stress. (4) Arch effect of an anticline/syncline will lessen vertical stress and increase horizontal stress. Paradoxically, the lessened vertical stress translates (via the Poisson’s ratio effect) to lowered horizontal stress. (5) Friction between lithological layers can suppress the bending beam effect. (6) Regional tectonic forces can influence horizontal stress and the arch effect. Models presented here are generated with the poro-elastic equation and with ABAQUS, a 2D/3D finite-element simulator that incorporates stress-strain relationships, gravity, pore pressure, far field (tectonic) stress and rock mechanical properties. We calculate vertical and horizontal stress distribution through three lithological layers and across a structural high. Results challenge common assumptions of seismic curvature: they show low stress sweet spots occur not only at the crest of an anticline but on the flanks too, and horizontal stress may be increasing or decreasing with depth, depending on lithology type and bounding layers. This study argues that traditional conclusions from curvature analysis should be scrutinised more closely, especially in application to unconventional reservoirs. Panel_15342 Panel_15342 8:30 AM 5:00 PM

Successful shale gas and tight oil production is enabled by the engineering innovation of horizontal well and hydraulic fracturing. In the reservoirs with ultra-low permeability, closely spaced hydraulic fractures and multilateral wells are required to improve production. Thus understanding the stress evolution and potential fracture interaction is critical in optimizing fracture/well design and completion strategy in multi-stage horizontal wells. In this paper, a new fully coupled flow and geomechanics model based on the dual-lattice system is developed to simulate multiple non-planar fractures propagation. The numerical model from Discrete Element Method (DEM) is used to simulate the mechanics of fracture propagations and interactions, while a conjugate irregular lattice network is generated to represent fluid flow in both fractures and formation. Initiation, growth and coalescence of the microcracks will lead to the generation of macroscopic fractures, which is explicitly mimicked by failure and removal of bonds between particles from the discrete element network. Based on above model, a sensitivity study is performed to investigate the effects of fracture spacing, in-situ stress anisotropy and fluid viscosity on hydraulic fracture propagation. The results show that fracture from one perforation cluster may inhibit the growth of neighboring perforation clusters due to the stress shadow effect. However, a larger initial in-situ anisotropy helps overcome this phenomenon. Reducing the viscosity of injection fluid was found to increase the possibility of hydraulic fracture branching, resulting in the formation of a more complex fracture network. This effect is not captured in traditional fracturing simulators. Multiple fractures creation both simultaneously and sequentially from horizontal wells is examined next. In simultaneous fracturing, fractures from the same horizontal well tend to repel each other while fractures from two different horizontal wells appear to attract each other. The curvature of fractures is controlled by the magnitude of stress shadow and far-field stress contrast. In sequential fracturing, the subsequent fracture trajectory is significantly affected by both fracture spacing and the fracture treatment in previous fractures. Finally, a case study on a shale reservoir in Eagle Ford is presented and this dual lattice DEM-Flow model is shown to capture realistic growth pattern of hydraulic fractures in heterogeneous reservoirs. Successful shale gas and tight oil production is enabled by the engineering innovation of horizontal well and hydraulic fracturing. In the reservoirs with ultra-low permeability, closely spaced hydraulic fractures and multilateral wells are required to improve production. Thus understanding the stress evolution and potential fracture interaction is critical in optimizing fracture/well design and completion strategy in multi-stage horizontal wells. In this paper, a new fully coupled flow and geomechanics model based on the dual-lattice system is developed to simulate multiple non-planar fractures propagation. The numerical model from Discrete Element Method (DEM) is used to simulate the mechanics of fracture propagations and interactions, while a conjugate irregular lattice network is generated to represent fluid flow in both fractures and formation. Initiation, growth and coalescence of the microcracks will lead to the generation of macroscopic fractures, which is explicitly mimicked by failure and removal of bonds between particles from the discrete element network. Based on above model, a sensitivity study is performed to investigate the effects of fracture spacing, in-situ stress anisotropy and fluid viscosity on hydraulic fracture propagation. The results show that fracture from one perforation cluster may inhibit the growth of neighboring perforation clusters due to the stress shadow effect. However, a larger initial in-situ anisotropy helps overcome this phenomenon. Reducing the viscosity of injection fluid was found to increase the possibility of hydraulic fracture branching, resulting in the formation of a more complex fracture network. This effect is not captured in traditional fracturing simulators. Multiple fractures creation both simultaneously and sequentially from horizontal wells is examined next. In simultaneous fracturing, fractures from the same horizontal well tend to repel each other while fractures from two different horizontal wells appear to attract each other. The curvature of fractures is controlled by the magnitude of stress shadow and far-field stress contrast. In sequential fracturing, the subsequent fracture trajectory is significantly affected by both fracture spacing and the fracture treatment in previous fractures. Finally, a case study on a shale reservoir in Eagle Ford is presented and this dual lattice DEM-Flow model is shown to capture realistic growth pattern of hydraulic fractures in heterogeneous reservoirs. Panel_15338 Panel_15338 8:30 AM 5:00 PM

Devonian age black shale deposition across foreland basins along the Appalachians has recently become very important economically because of their gas-shale potential. Understanding the natural fracture patterns is important for unconventional gas-shale reservoirs because natural fractures play a vital role in the movement of fluids such as oil and gas, and are also a critical controlling factor in the adequate distribution of hydraulic fracture treatments of gas-shale reservoirs. In Alabama, Shale Gas targets including the Chattanooga are being explored for their gas potential. We have collected LIDAR images from a Chattanooga shale outcrop along the backlimb of the Wills Valley Anticline. LIDAR image acquisition and analysis advance the ability to characterize outcrops in terms of accuracy across the exposure as well as fracture relationships within the bedding. LIDAR imaging of Chattanooga Shale allows for quantitative capture of fracture geometry, orientation, and density. We are using these images to determine the relationship between bedding thickness and fracture density in the Cherty beds of the Chattanooga Shale. The chert content in the Chattanooga outcrop increases upsection. We have obtained three 1 m2 close up scan images from three distinctive lithologies of the outcrop. The first one is close to the base of the unit with high organic content and very low chert content. The second one is in middle of the section with intermediate organic content and intermediate chert content. The third one is higher in the section with a very low organic content and high chert content. Our preliminary interpretation suggest that the shale unit tends to be better fractured in the chert rich beds of than the organic rich beds. The chert rich beds contain well developed orthogonal fracture pattern. We are in the process of quantifying a) the chert and organic content of the Chattanooga shale; and b) fracture density and fracture length and their relationship to the bed thickness in three different scanned images. Fractures within the Chattanooga Shale also offer potential insight into subsurface natural fracturing as well as local and regional stress environments when the Wills Valley Anticline developed during the Alleghanian orogeny. Devonian age black shale deposition across foreland basins along the Appalachians has recently become very important economically because of their gas-shale potential. Understanding the natural fracture patterns is important for unconventional gas-shale reservoirs because natural fractures play a vital role in the movement of fluids such as oil and gas, and are also a critical controlling factor in the adequate distribution of hydraulic fracture treatments of gas-shale reservoirs. In Alabama, Shale Gas targets including the Chattanooga are being explored for their gas potential. We have collected LIDAR images from a Chattanooga shale outcrop along the backlimb of the Wills Valley Anticline. LIDAR image acquisition and analysis advance the ability to characterize outcrops in terms of accuracy across the exposure as well as fracture relationships within the bedding. LIDAR imaging of Chattanooga Shale allows for quantitative capture of fracture geometry, orientation, and density. We are using these images to determine the relationship between bedding thickness and fracture density in the Cherty beds of the Chattanooga Shale. The chert content in the Chattanooga outcrop increases upsection. We have obtained three 1 m2 close up scan images from three distinctive lithologies of the outcrop. The first one is close to the base of the unit with high organic content and very low chert content. The second one is in middle of the section with intermediate organic content and intermediate chert content. The third one is higher in the section with a very low organic content and high chert content. Our preliminary interpretation suggest that the shale unit tends to be better fractured in the chert rich beds of than the organic rich beds. The chert rich beds contain well developed orthogonal fracture pattern. We are in the process of quantifying a) the chert and organic content of the Chattanooga shale; and b) fracture density and fracture length and their relationship to the bed thickness in three different scanned images. Fractures within the Chattanooga Shale also offer potential insight into subsurface natural fracturing as well as local and regional stress environments when the Wills Valley Anticline developed during the Alleghanian orogeny. Panel_15336 Panel_15336 8:30 AM 5:00 PM

Panel_14472 Panel_14472 8:30 AM 5:00 PM

A detachment can be defined as a horizon or zone, centimeters to kilometers in thickness, which mechanically decouples deforming rocks or sediments from underlying, non-deforming sequences. Shale detachments have been previously described as largely ductile in their mechanism of deformation, however, increasing resolution of seismic imaging and understanding of these zones suggest brittle, fault-dominated deformation may have a significant role in their behavior and the deformation of overlying fold and thrust belts. Dependence on seismic imaging and other indirect and low-resolution study methods has resulted from the lack of outcropping shale detachment zones for detailed study. Recent investigation details the structural style of an exceptionally well-exposed upper-level shale detachment zone in the Sap Bon Formation of the Khao Khwang Fold and Thrust Belt, Central Thailand. We use detailed structural analysis to investigate the deformational mechanisms of this exhumed detachment zone, as an analogue to active modern-day examples. We present detailed structural cross-sections through the detachment zone and use a multi-analysis approach to constrain geochemistry and deformational temperature given the potential influence on the rheology of the detachment zone when active. Carbon and oxygen stable isotope geochemistry is used to investigate the temperature of syn-deformational fluid flow while illite crystallinity analysis is used to estimate the maximum deformational temperature. Deformational complexity and intensity increases with proximity to the basal thrust of the detachment zone and is associated with increasing temperature of syn-deformational fluids and higher TOC values. Centimeter-scale ‘shale shear zones’ within the Sap Bon Formation accommodate significant shortening in complex, three-dimensional geometries and are associated with higher degree of illite crystallinity values. These shear zones exhibit higher strain than surrounding rock, and a quantitative relationship between finite strain (RS) and illite crystallinity is observed. These shear zones and associated structural features occur at a scale well beyond the resolution of seismic imaging. Finally, we present a suite new data and structural interpretation from other known shale detachments in the Chrystalls Beach Complex in southern Otago, New Zealand, and the Osen Røa thrust sheet in the Norwegian Caledonides, for comparison with results from the Khao Khwang FTB. A detachment can be defined as a horizon or zone, centimeters to kilometers in thickness, which mechanically decouples deforming rocks or sediments from underlying, non-deforming sequences. Shale detachments have been previously described as largely ductile in their mechanism of deformation, however, increasing resolution of seismic imaging and understanding of these zones suggest brittle, fault-dominated deformation may have a significant role in their behavior and the deformation of overlying fold and thrust belts. Dependence on seismic imaging and other indirect and low-resolution study methods has resulted from the lack of outcropping shale detachment zones for detailed study. Recent investigation details the structural style of an exceptionally well-exposed upper-level shale detachment zone in the Sap Bon Formation of the Khao Khwang Fold and Thrust Belt, Central Thailand. We use detailed structural analysis to investigate the deformational mechanisms of this exhumed detachment zone, as an analogue to active modern-day examples. We present detailed structural cross-sections through the detachment zone and use a multi-analysis approach to constrain geochemistry and deformational temperature given the potential influence on the rheology of the detachment zone when active. Carbon and oxygen stable isotope geochemistry is used to investigate the temperature of syn-deformational fluid flow while illite crystallinity analysis is used to estimate the maximum deformational temperature. Deformational complexity and intensity increases with proximity to the basal thrust of the detachment zone and is associated with increasing temperature of syn-deformational fluids and higher TOC values. Centimeter-scale ‘shale shear zones’ within the Sap Bon Formation accommodate significant shortening in complex, three-dimensional geometries and are associated with higher degree of illite crystallinity values. These shear zones exhibit higher strain than surrounding rock, and a quantitative relationship between finite strain (RS) and illite crystallinity is observed. These shear zones and associated structural features occur at a scale well beyond the resolution of seismic imaging. Finally, we present a suite new data and structural interpretation from other known shale detachments in the Chrystalls Beach Complex in southern Otago, New Zealand, and the Osen Røa thrust sheet in the Norwegian Caledonides, for comparison with results from the Khao Khwang FTB. Panel_15355 Panel_15355 8:30 AM 8:30 AM

The Lower Magdalena Valley (LMV) and the adjacent San Jacinto Fold Belt (SJFB), have been considered as two distinct basins separated by the Romeral Fault System (RFS). This fault has been mapped from the Central Cordillera and extended to the North, along the beginning of the deformation of SJFB. However, few sub-surface imaging has been published in order to understand better this structural limit and its relation during the evolution of the northern part of Colombia from the Late Cretaceous to the Oligocene. During the last decade, the Colombia National Hydrocarbons Agency has acquired data wells that add considerable insight on these two important basins. In the Southern part of LMV and SJFB, there are two main stratigraphic packages: Upper Cretaceous – Paleocene and middle Eocene – Oligocene, separated by an early to middle Eocene unconformity. The pre-unconformity sequence includes the Cansona and San Cayetano formations, a very thick sequence deformed by thrust faults. Evidence of compression prior to the unconformity is shown in some areas, related to the accretion of the oceanic crust. The post-unconformity sequence includes the Chengue, Toluviejo, San Jacinto and Ciénaga de Oro formations. This sequence is comprised by several cycles that filled the basin progressively from Northwest to Southeast. The RFS was an active basin edge until early to middle Eocene times; afterwards, the topography was already created and the post-unconformity sequence was deposited with no major influence of the existing fault system. The limit of Oceanic and Continental Crust can be placed further to the East of the SJFB, at least in the area of El Cabano-1 well, as seismic images show that the Cretaceous – Paleocene sequence is still present below and strong reflectors are not the top of the Basement as was previously thought. U-Pb data from El Cabano-1 well, indicates that these reflectors seen below the Unconformity are Paleocene-Eocene in age, which agrees with the seismic correlation. These new data provide important information that shows that the RFS, acted during the formation of the LMV, and that the main activity took place before the Middle-Eocene. Recent tectonic deformation that caused the formation of the SJFB is not related to the activity of the RFS, but the result of the compression between the Caribe and South American deforming all the sequence, using the Cansona shales as a detachment zone. The Lower Magdalena Valley (LMV) and the adjacent San Jacinto Fold Belt (SJFB), have been considered as two distinct basins separated by the Romeral Fault System (RFS). This fault has been mapped from the Central Cordillera and extended to the North, along the beginning of the deformation of SJFB. However, few sub-surface imaging has been published in order to understand better this structural limit and its relation during the evolution of the northern part of Colombia from the Late Cretaceous to the Oligocene. During the last decade, the Colombia National Hydrocarbons Agency has acquired data wells that add considerable insight on these two important basins. In the Southern part of LMV and SJFB, there are two main stratigraphic packages: Upper Cretaceous – Paleocene and middle Eocene – Oligocene, separated by an early to middle Eocene unconformity. The pre-unconformity sequence includes the Cansona and San Cayetano formations, a very thick sequence deformed by thrust faults. Evidence of compression prior to the unconformity is shown in some areas, related to the accretion of the oceanic crust. The post-unconformity sequence includes the Chengue, Toluviejo, San Jacinto and Ciénaga de Oro formations. This sequence is comprised by several cycles that filled the basin progressively from Northwest to Southeast. The RFS was an active basin edge until early to middle Eocene times; afterwards, the topography was already created and the post-unconformity sequence was deposited with no major influence of the existing fault system. The limit of Oceanic and Continental Crust can be placed further to the East of the SJFB, at least in the area of El Cabano-1 well, as seismic images show that the Cretaceous – Paleocene sequence is still present below and strong reflectors are not the top of the Basement as was previously thought. U-Pb data from El Cabano-1 well, indicates that these reflectors seen below the Unconformity are Paleocene-Eocene in age, which agrees with the seismic correlation. These new data provide important information that shows that the RFS, acted during the formation of the LMV, and that the main activity took place before the Middle-Eocene. Recent tectonic deformation that caused the formation of the SJFB is not related to the activity of the RFS, but the result of the compression between the Caribe and South American deforming all the sequence, using the Cansona shales as a detachment zone. Panel_15354 Panel_15354 8:30 AM 8:30 AM

The central Rocky Mountain region in the western interior of U.S.A. consists of a sequence of basement-cored mountain ranges and intervening petroleum-bearing basins. The area was situated within the foreland of the Cordilleran retroarc thrust belt during the Cretaceous, and was partitioned by the Laramide deformation during the latest Cretaceous-early Eocene. Although it is generally agreed that the Laramide deformation was caused by the low-angle subduction of the Farallon oceanic plate underneath western U.S.A., recent studies suggest that hot asthenospheric upwelling associated with slab-removal may be the major driver of the deformation. Here we test whether mantle processes induced by slab-removal may have influenced the formation of these intermontane basins in the state of Wyoming. We assume that the Wyoming lithosphere behaved as an infinite elastic beam under the tectonic loading of the Laramide ranges, and conduct 2D flexural subsidence modeling to the intermontane basins in order to document the temporal and spatial variations of mountain size and lithosphere flexural rigidity (D). The decompacted profile of basin fill along a transect perpendicular to the basin-bounding mountain range represents the observed amount of flexural subsidence. We derive the mountain size and D by matching modeled subsidence profile to the observed subsidence profile. Our results show that the Laramide ranges gained elevations equal to or higher than their present mean elevations during the Laramide deformation, and the uplift of most of the ranges accelerated during the early Eocene. D remained relatively constant in each basin, but decreased from northeastern Wyoming (~1023 Nm) to southwestern Wyoming (~1020 Nm) during the Laramide deformation. When compared to the Wyoming lithosphere strength (D=1023-24 Nm) during the late Cretaceous and at present, the lithosphere in southwestern and central Wyoming was weakened during the Laramide deformation. We suggest that the uplift of the Laramide ranges and the weakening of the Wyoming lithosphere were caused by the breakoff and subsequent removal of the Farallon flat slab. The flat slab may break off underneath southwestern Wyoming, and the associated asthenospheric upwelling thermally weakened the lithosphere. The loading of Laramide ranges and weakening of lithosphere caused the fast subsidence of the intermontane basins, which contributed significantly to the burial and maturation of the Cretaceous source rocks. The central Rocky Mountain region in the western interior of U.S.A. consists of a sequence of basement-cored mountain ranges and intervening petroleum-bearing basins. The area was situated within the foreland of the Cordilleran retroarc thrust belt during the Cretaceous, and was partitioned by the Laramide deformation during the latest Cretaceous-early Eocene. Although it is generally agreed that the Laramide deformation was caused by the low-angle subduction of the Farallon oceanic plate underneath western U.S.A., recent studies suggest that hot asthenospheric upwelling associated with slab-removal may be the major driver of the deformation. Here we test whether mantle processes induced by slab-removal may have influenced the formation of these intermontane basins in the state of Wyoming. We assume that the Wyoming lithosphere behaved as an infinite elastic beam under the tectonic loading of the Laramide ranges, and conduct 2D flexural subsidence modeling to the intermontane basins in order to document the temporal and spatial variations of mountain size and lithosphere flexural rigidity (D). The decompacted profile of basin fill along a transect perpendicular to the basin-bounding mountain range represents the observed amount of flexural subsidence. We derive the mountain size and D by matching modeled subsidence profile to the observed subsidence profile. Our results show that the Laramide ranges gained elevations equal to or higher than their present mean elevations during the Laramide deformation, and the uplift of most of the ranges accelerated during the early Eocene. D remained relatively constant in each basin, but decreased from northeastern Wyoming (~1023 Nm) to southwestern Wyoming (~1020 Nm) during the Laramide deformation. When compared to the Wyoming lithosphere strength (D=1023-24 Nm) during the late Cretaceous and at present, the lithosphere in southwestern and central Wyoming was weakened during the Laramide deformation. We suggest that the uplift of the Laramide ranges and the weakening of the Wyoming lithosphere were caused by the breakoff and subsequent removal of the Farallon flat slab. The flat slab may break off underneath southwestern Wyoming, and the associated asthenospheric upwelling thermally weakened the lithosphere. The loading of Laramide ranges and weakening of lithosphere caused the fast subsidence of the intermontane basins, which contributed significantly to the burial and maturation of the Cretaceous source rocks. Panel_15356 Panel_15356 8:30 AM 8:30 AM

The NE-trending Tan-Lu fault zone is a large-scale strike-slipping fault zone which traverses the eastern side of the Bohai Bay basin, eastern China. There are many controversies on its deformation and evolution for a long time. In order to meet the needs of oil and gas exploration in the offshore Bohai Bay basin, many high-quality 3D seismic surverys have been acquired in the past decade, which affords an exceptional opportunity to study the structural features of the Tan-Lu fault zone. The newest 3D seismic data show that the along-strike segmentation of the Tan-Lu fault zone are obvious in the offshore Bohai Bay basin. Based on its deformation difference in various areas, the Tan-Lu fault zone can be divided into three large segments with more subsegments. The northern segment which is located in the eastern part of the Liaodongwan depression has the narrowest distribution area in plane, and the most predominant strike-slipping characteristics. The segment comprise of 2-3 major faults with length of about 200km, which act as the boundary faults between elongated uplifts and sags. The middle segment in the Bozhong depression is composed of several branch fault zones with poor continuity and wider distribution area. The part has mixed features of strike-slipping and extensional deformation. The southern segment in the Bonan depression which is mainly controlled by EW-trending extensional faults comprises of three branch fault zones, each of them has multiple faults. The segment has the widest distribution area, and the branch fault zones are nearly vertical in cross sections. Compared to EW-trending extensional faults, the NNE-trending southern segment experienced later activity and cut the former extensional faults. The former studies addressed that the rhombic sags within the Bonan depression were pull-apart subbasin resulted from the dextral strike-slipping movement of the Tan-Lu fault zone. The new 3D seismic data, however, confirm that they should be extensional faulted sags which are also reformed by the Tau-Lu fault zone. The NE-trending Tan-Lu fault zone is a large-scale strike-slipping fault zone which traverses the eastern side of the Bohai Bay basin, eastern China. There are many controversies on its deformation and evolution for a long time. In order to meet the needs of oil and gas exploration in the offshore Bohai Bay basin, many high-quality 3D seismic surverys have been acquired in the past decade, which affords an exceptional opportunity to study the structural features of the Tan-Lu fault zone. The newest 3D seismic data show that the along-strike segmentation of the Tan-Lu fault zone are obvious in the offshore Bohai Bay basin. Based on its deformation difference in various areas, the Tan-Lu fault zone can be divided into three large segments with more subsegments. The northern segment which is located in the eastern part of the Liaodongwan depression has the narrowest distribution area in plane, and the most predominant strike-slipping characteristics. The segment comprise of 2-3 major faults with length of about 200km, which act as the boundary faults between elongated uplifts and sags. The middle segment in the Bozhong depression is composed of several branch fault zones with poor continuity and wider distribution area. The part has mixed features of strike-slipping and extensional deformation. The southern segment in the Bonan depression which is mainly controlled by EW-trending extensional faults comprises of three branch fault zones, each of them has multiple faults. The segment has the widest distribution area, and the branch fault zones are nearly vertical in cross sections. Compared to EW-trending extensional faults, the NNE-trending southern segment experienced later activity and cut the former extensional faults. The former studies addressed that the rhombic sags within the Bonan depression were pull-apart subbasin resulted from the dextral strike-slipping movement of the Tan-Lu fault zone. The new 3D seismic data, however, confirm that they should be extensional faulted sags which are also reformed by the Tau-Lu fault zone. Panel_15364 Panel_15364 8:30 AM 8:30 AM

Physical models predict that multiphase rifts which have experienced a change in extension direction between stretching phases will typically develop non-colinear normal fault sets and hence will display a greater frequency and range of styles of fault interactions than single-phase rifts. We test these model-based predictions by studying a natural fault network in the northern Horda Platform, northern North Sea using an integrated 3D seismic reflection and borehole dataset. We focus on the >60 km long, N-S-striking Tusse fault that has over 500 m of throw and was active in the Permian-Triassic and again in the Late Jurassic-to-Early Cretaceous. The Tusse Fault forms part of a non-colinear fault network that also comprises numerous smaller (2-10 km long), lower throw (<100 m) and predominantly NW-SE-striking faults that were only active during the Late Jurassic to Early Cretaceous. We examine how the 2nd-stage NW-SE-striking faults have grown and interacted with the N-S-striking Tusse Fault, noting a series of key end-member styles including faults that are: i) isolated and non-interacting; ii) abutting; iii) cross-cutting; and iv) hybrid. To constrain the nucleation sites, growth histories and diagnostic throw distributions associated with each interaction style, we apply throw-versus-length (T-x), throw-versus-depth (T-z) and 3D strike-projection throw contouring techniques to key faults. Our results show that: i) pre-existing (1st-stage) faults can act as sites of nucleation for 2nd-stage faults; ii) abutting relationships are particularly common and can develop by 2nd-stage faults nucleating either at, or away from pre-existing faults; iii) the throw distribution on reactivated 1st-stage faults will be modified in a predictable manner if they are intersected or influenced by 2nd-stage faults; and iv) fault segment boundaries, and fault kinks or corrugations along 1st-stage faults, can act as preferential nucleation sites for 2nd-stage faults, and facilitate the development of complex cross-cutting relationships. In addition to furthering fundamental understanding of the characteristic geometries, kinematics and throw distributions of normal faults in multiphase rifts, our results also have broader implications for understanding the physiographic and tectono-stratigraphic evolution of multiphase rift basins. Physical models predict that multiphase rifts which have experienced a change in extension direction between stretching phases will typically develop non-colinear normal fault sets and hence will display a greater frequency and range of styles of fault interactions than single-phase rifts. We test these model-based predictions by studying a natural fault network in the northern Horda Platform, northern North Sea using an integrated 3D seismic reflection and borehole dataset. We focus on the >60 km long, N-S-striking Tusse fault that has over 500 m of throw and was active in the Permian-Triassic and again in the Late Jurassic-to-Early Cretaceous. The Tusse Fault forms part of a non-colinear fault network that also comprises numerous smaller (2-10 km long), lower throw (<100 m) and predominantly NW-SE-striking faults that were only active during the Late Jurassic to Early Cretaceous. We examine how the 2nd-stage NW-SE-striking faults have grown and interacted with the N-S-striking Tusse Fault, noting a series of key end-member styles including faults that are: i) isolated and non-interacting; ii) abutting; iii) cross-cutting; and iv) hybrid. To constrain the nucleation sites, growth histories and diagnostic throw distributions associated with each interaction style, we apply throw-versus-length (T-x), throw-versus-depth (T-z) and 3D strike-projection throw contouring techniques to key faults. Our results show that: i) pre-existing (1st-stage) faults can act as sites of nucleation for 2nd-stage faults; ii) abutting relationships are particularly common and can develop by 2nd-stage faults nucleating either at, or away from pre-existing faults; iii) the throw distribution on reactivated 1st-stage faults will be modified in a predictable manner if they are intersected or influenced by 2nd-stage faults; and iv) fault segment boundaries, and fault kinks or corrugations along 1st-stage faults, can act as preferential nucleation sites for 2nd-stage faults, and facilitate the development of complex cross-cutting relationships. In addition to furthering fundamental understanding of the characteristic geometries, kinematics and throw distributions of normal faults in multiphase rifts, our results also have broader implications for understanding the physiographic and tectono-stratigraphic evolution of multiphase rift basins. Panel_15360 Panel_15360 8:30 AM 8:30 AM

Hydrocarbon column height is a crucial parameter in predicting prospect volumes. A difference of a few meters may significantly alter a prospect’s estimated success-case volumes. Such sensitivity renders accurate prediction of column height critically important when evaluating prospects for drilling and acreage-capture decisions. In the absence of direct hydrocarbon indicators (DHIs) or known fill controls, column-height modeling must rely on a synthesis of empirical observations from existing discoveries. An extensive compilation of global column-height data demonstrates how trap geometry, genetic history and geologic setting influence the relative roles exacted by various hydrocarbon exit mechanisms (i.e. synclinal spill, fault juxtaposition, erosional leak, capillary leak, and mechanical seal failure). The results also highlight the interplay among trap closure height, seal capacity, and fluid type, as postulated by Sales (1997). Analysis of column-height data for traps containing both oil and gas enable estimation of the capillary entry pressure controlling fluid-contact elevations and provide a proxy for regional seal capacity. Globally, 40% of structures shorter than 250m fill to synclinal spill point. The data suggests combining a uniform column-height distribution with a filled-to-spill distribution, weighted between zero and 0.4, for modeling prospects between 250 and 800m tall. However, the use of global benchmarks for column-height prediction is discouraged without careful consideration of trap-specific geology. Fill patterns for broad, low relief traps contradict the hypothesis that the probability of encountering a cryptic leak, i.e. an unresolved fault juxtaposition or erosional leak, increasing exponentially in probability from trap crest down structure. Characterization of effective seal area for various top-seal lithologies provides an estimate of cryptic leak distribution. The use of a shallow leak contact model, versus a uniform distribution, is suggested when prospect area is much larger than the effective seal area. These results provide a framework to determine two critical inputs for prospect evaluation: (1) the probability functions most appropriate for modeling column height and (2) the weighting of these functions to best reflect the relative likelihood of various fill-control scenarios. This approach is more objective than other methods, which can fail to accurately capture the range and probability of column-height uncertainty. Hydrocarbon column height is a crucial parameter in predicting prospect volumes. A difference of a few meters may significantly alter a prospect’s estimated success-case volumes. Such sensitivity renders accurate prediction of column height critically important when evaluating prospects for drilling and acreage-capture decisions. In the absence of direct hydrocarbon indicators (DHIs) or known fill controls, column-height modeling must rely on a synthesis of empirical observations from existing discoveries. An extensive compilation of global column-height data demonstrates how trap geometry, genetic history and geologic setting influence the relative roles exacted by various hydrocarbon exit mechanisms (i.e. synclinal spill, fault juxtaposition, erosional leak, capillary leak, and mechanical seal failure). The results also highlight the interplay among trap closure height, seal capacity, and fluid type, as postulated by Sales (1997). Analysis of column-height data for traps containing both oil and gas enable estimation of the capillary entry pressure controlling fluid-contact elevations and provide a proxy for regional seal capacity. Globally, 40% of structures shorter than 250m fill to synclinal spill point. The data suggests combining a uniform column-height distribution with a filled-to-spill distribution, weighted between zero and 0.4, for modeling prospects between 250 and 800m tall. However, the use of global benchmarks for column-height prediction is discouraged without careful consideration of trap-specific geology. Fill patterns for broad, low relief traps contradict the hypothesis that the probability of encountering a cryptic leak, i.e. an unresolved fault juxtaposition or erosional leak, increasing exponentially in probability from trap crest down structure. Characterization of effective seal area for various top-seal lithologies provides an estimate of cryptic leak distribution. The use of a shallow leak contact model, versus a uniform distribution, is suggested when prospect area is much larger than the effective seal area. These results provide a framework to determine two critical inputs for prospect evaluation: (1) the probability functions most appropriate for modeling column height and (2) the weighting of these functions to best reflect the relative likelihood of various fill-control scenarios. This approach is more objective than other methods, which can fail to accurately capture the range and probability of column-height uncertainty. Panel_15363 Panel_15363 8:30 AM 8:30 AM

Predicting the sealing capacity of carbonate fault zones is complicated by the heterogeneity of intact carbonates and their respective fault rock textures, and the propensity for carbonates to respond to fluids and diagenetic processes. Carbonate-hosted extensional fault zones have been examined for locations of fault rock, types of fault rock produced and their influence on a fault’s hydraulic behaviour. The location of fault rock affects fluid flow pathways across/along faults and is dependent on the fault’s architecture. Fault zones with multiple slip surfaces often occur in weaker carbonates, distributing fault rock and preventing production of a continuous fault core at lower displacements, allowing fluids to flow across the fault. The sealing potential is also a function of the deformation mechanisms active during fault rock production. Lithological heterogeneity in a faulted carbonate succession leads to a variety of deformation mechanisms, generating several fault rock types with a range of microstructures along a single slip surface. The types of fault rock produced is a function of the host rock texture, specifically grain size, sorting, porosity and strength. Dispersed deformation creates large fracture networks within homogeneously fine-grained, weaker carbonates. In contrast, localised deformation occurs in heterogeneous, coarse-grained, stronger carbonates, creating cataclasite and cemented fault rocks. Each microstructure has different poroperm values, varying along-strike and down-dip. Permeability of all analysed fault rocks range from 0.0001 to >1000 mD and porosities vary from 1.6% to 34.7%. However, trends to the variable poroperm are observed, dependent on host lithofacies, juxtaposition and displacement. Mixing of different lithofacies at higher displacements increases the types of deformation mechanisms active, creating a variety of fault rocks, each with different poroperm values. This causes faults to have a negligible response when simulating reservoir models, with transmissibility multipliers of c. 0.86. Conversely, juxtaposition of similar lithofacies increases the fault rock homogeneity including their poroperm, and reduces the transmissibility multipliers to 0.001, causing the faults to significantly reduce flow. Understanding the deformation mechanisms active during faulting of a carbonate sequence aids prediction of the types of fault rocks formed, their hydraulic properties and influence during reservoir simulation. Predicting the sealing capacity of carbonate fault zones is complicated by the heterogeneity of intact carbonates and their respective fault rock textures, and the propensity for carbonates to respond to fluids and diagenetic processes. Carbonate-hosted extensional fault zones have been examined for locations of fault rock, types of fault rock produced and their influence on a fault’s hydraulic behaviour. The location of fault rock affects fluid flow pathways across/along faults and is dependent on the fault’s architecture. Fault zones with multiple slip surfaces often occur in weaker carbonates, distributing fault rock and preventing production of a continuous fault core at lower displacements, allowing fluids to flow across the fault. The sealing potential is also a function of the deformation mechanisms active during fault rock production. Lithological heterogeneity in a faulted carbonate succession leads to a variety of deformation mechanisms, generating several fault rock types with a range of microstructures along a single slip surface. The types of fault rock produced is a function of the host rock texture, specifically grain size, sorting, porosity and strength. Dispersed deformation creates large fracture networks within homogeneously fine-grained, weaker carbonates. In contrast, localised deformation occurs in heterogeneous, coarse-grained, stronger carbonates, creating cataclasite and cemented fault rocks. Each microstructure has different poroperm values, varying along-strike and down-dip. Permeability of all analysed fault rocks range from 0.0001 to >1000 mD and porosities vary from 1.6% to 34.7%. However, trends to the variable poroperm are observed, dependent on host lithofacies, juxtaposition and displacement. Mixing of different lithofacies at higher displacements increases the types of deformation mechanisms active, creating a variety of fault rocks, each with different poroperm values. This causes faults to have a negligible response when simulating reservoir models, with transmissibility multipliers of c. 0.86. Conversely, juxtaposition of similar lithofacies increases the fault rock homogeneity including their poroperm, and reduces the transmissibility multipliers to 0.001, causing the faults to significantly reduce flow. Understanding the deformation mechanisms active during faulting of a carbonate sequence aids prediction of the types of fault rocks formed, their hydraulic properties and influence during reservoir simulation. Panel_15365 Panel_15365 8:30 AM 8:30 AM

Rift basins often form within lithosphere containing structures imparted from previous tectonic events, yet the extent to which the reactivation of these structures affects the evolution of rifts is poorly understood. Several key aspects of petroleum system development, such as the timing of trap formation and distribution of syn-rift sediments, may be influenced by reactivated intra-crystalline basement (ICB) structures. However, determining the impact of ICB structure on rift evolution is difficult as crystalline basement is often buried beneath thick sedimentary successions and contains small acoustic impedance contrasts. Therefore, crystalline basement typically appears poorly reflective on seismic reflection data, hampering efforts to interpret internal structure. In this study we use borehole-constrained 2D and 3D seismic reflection data from offshore SW Norway to map a series of prominent ICB reflections, and document how they affect rift evolution. Crystalline basement is exceptionally well-imaged throughout the data due to large impedance contrasts within a highly heterogeneous, shallow basement, allowing for the 3D mapping of ICB structure. From our analyses, we observe two types of structure: i) Type 1 - thin (100 m) reflection packages, showing a ramp-flat geometry; and ii) Type 2 - thick (1 km), steeply dipping (30°) packages comprising multiple reflections. These structures correlate northwards along-strike to Caledonian orogeny-related structures mapped onshore southern Norway. Based on this spatial relationship we interpret the structures as Caledonian thrusts (Type 1) and large-scale Devonian shear zones (Type 2). We observe multiple phases of extensional reactivation of some ICB structures during Devonian, Permo-Triassic and Late Jurassic-Early Cretaceous rifting, along with reverse reactivation during Late Cretaceous inversion. However, rifting is also associated with the initiation of faults that cross-cut ICB structure; implying selective reactivation of ICB structures, which may be controlled by their relative strength and geometry. From detailed 3D mapping of an ancient thrust belt and overlying rift, we show that the presence of ICB structures can control the structure and evolution of rift basins. Selective reactivation of ICB structures will control the location and orientation of major rift-related faults. Repeated reactivation of these structures during later rifting may modify pre-existing structural traps or migration pathways. Rift basins often form within lithosphere containing structures imparted from previous tectonic events, yet the extent to which the reactivation of these structures affects the evolution of rifts is poorly understood. Several key aspects of petroleum system development, such as the timing of trap formation and distribution of syn-rift sediments, may be influenced by reactivated intra-crystalline basement (ICB) structures. However, determining the impact of ICB structure on rift evolution is difficult as crystalline basement is often buried beneath thick sedimentary successions and contains small acoustic impedance contrasts. Therefore, crystalline basement typically appears poorly reflective on seismic reflection data, hampering efforts to interpret internal structure. In this study we use borehole-constrained 2D and 3D seismic reflection data from offshore SW Norway to map a series of prominent ICB reflections, and document how they affect rift evolution. Crystalline basement is exceptionally well-imaged throughout the data due to large impedance contrasts within a highly heterogeneous, shallow basement, allowing for the 3D mapping of ICB structure. From our analyses, we observe two types of structure: i) Type 1 - thin (100 m) reflection packages, showing a ramp-flat geometry; and ii) Type 2 - thick (1 km), steeply dipping (30°) packages comprising multiple reflections. These structures correlate northwards along-strike to Caledonian orogeny-related structures mapped onshore southern Norway. Based on this spatial relationship we interpret the structures as Caledonian thrusts (Type 1) and large-scale Devonian shear zones (Type 2). We observe multiple phases of extensional reactivation of some ICB structures during Devonian, Permo-Triassic and Late Jurassic-Early Cretaceous rifting, along with reverse reactivation during Late Cretaceous inversion. However, rifting is also associated with the initiation of faults that cross-cut ICB structure; implying selective reactivation of ICB structures, which may be controlled by their relative strength and geometry. From detailed 3D mapping of an ancient thrust belt and overlying rift, we show that the presence of ICB structures can control the structure and evolution of rift basins. Selective reactivation of ICB structures will control the location and orientation of major rift-related faults. Repeated reactivation of these structures during later rifting may modify pre-existing structural traps or migration pathways. Panel_15357 Panel_15357 8:30 AM 8:30 AM

The intersection of regional seismic profiles with a high-resolution 3D seismic volume in the central Illinois Basin provides a unique opportunity to expand our understanding of deep Paleozoic and Precambrian structure related to basin development. The new data, acquired in Decatur, Illinois and extending east and west across the basin, allow the northward continuation of geophysical observations from the better-studied southern portion of the Illinois Basin. The geophysical interpretation of both profiles and volume data was guided by application of a suite of seismic attribute calculations, including reflection heterogeneity and cosine of phase angle. Geological interpretation is constrained locally by new deep drill-hole data, which reveal a rhyolitic Precambrian “basement.” The seismic data volume provides a detailed 3D view of internal basement reflectivity beneath the basin (i.e., below the base of the Cambrian Mt. Simon Sandstone), expressed locally as a very strong dipping reflector. This strong reflector could be evidence of volcani-clastic material associated with rhyolitic volcanism; or part of a sequence of basaltic sills intruded into a known granitic-composition basement, as hypothesized from geophysical data further south in the Illinois Basin. The basement reflector may be overlain by a possible “wedge” of relatively horizontal reflectivity, interpretable as a “seismic stratigraphic” sequence, similar to Precambrian sequences mapped further south in the basin; however, we also investigate the possible influence of complex-path multiple reflections generated in the lower Paleozoic portion of the seismic data volume. Lower Paleozoic and upper basement structure can also be well-resolved on the new regional 2D seismic data. For example, possible syn-depositional faults appear to affect the lower part of the Paleozoic stratigraphic section, possibly extending into Precambrian basement. Both, these faults and the Precambrian reflectivity, spatially correlate to a regional north-south elongated zone of thickened Mt. Simon Sandstone. The thickened zone of Mt. Simon can be interpreted as a zone of early Paleozoic rifting, possibly associated with the break-up of the Supercontinent of Rodinia. The intersection of regional seismic profiles with a high-resolution 3D seismic volume in the central Illinois Basin provides a unique opportunity to expand our understanding of deep Paleozoic and Precambrian structure related to basin development. The new data, acquired in Decatur, Illinois and extending east and west across the basin, allow the northward continuation of geophysical observations from the better-studied southern portion of the Illinois Basin. The geophysical interpretation of both profiles and volume data was guided by application of a suite of seismic attribute calculations, including reflection heterogeneity and cosine of phase angle. Geological interpretation is constrained locally by new deep drill-hole data, which reveal a rhyolitic Precambrian “basement.” The seismic data volume provides a detailed 3D view of internal basement reflectivity beneath the basin (i.e., below the base of the Cambrian Mt. Simon Sandstone), expressed locally as a very strong dipping reflector. This strong reflector could be evidence of volcani-clastic material associated with rhyolitic volcanism; or part of a sequence of basaltic sills intruded into a known granitic-composition basement, as hypothesized from geophysical data further south in the Illinois Basin. The basement reflector may be overlain by a possible “wedge” of relatively horizontal reflectivity, interpretable as a “seismic stratigraphic” sequence, similar to Precambrian sequences mapped further south in the basin; however, we also investigate the possible influence of complex-path multiple reflections generated in the lower Paleozoic portion of the seismic data volume. Lower Paleozoic and upper basement structure can also be well-resolved on the new regional 2D seismic data. For example, possible syn-depositional faults appear to affect the lower part of the Paleozoic stratigraphic section, possibly extending into Precambrian basement. Both, these faults and the Precambrian reflectivity, spatially correlate to a regional north-south elongated zone of thickened Mt. Simon Sandstone. The thickened zone of Mt. Simon can be interpreted as a zone of early Paleozoic rifting, possibly associated with the break-up of the Supercontinent of Rodinia. Panel_15358 Panel_15358 8:30 AM 8:30 AM

Located at the intersection between NW-trending slip system and NE-trending rift system in the northern South China Sea, the Central Depression of Qiongdongnan Basin (CDQB) and adjacent areas embed critical information on Indochina block extrusion and South China Sea seafloor spreading. In this study, we systematically reveal the striking structural differences between the western and eastern CDQB from fault distribution, depression form, rifting pattern, fault activities and structure evolution. A semi-quantitative analysis of the fault cut-offs identifies four stages of rifting evolution: (1) 45–32 Ma, sparsely distributed NE-trending faults formed mainly in the western and the central part of the study area; (2) 32–28.4 Ma, the area influenced by NE-trending faulting was extended into the eastern part of the study area and some NW-trending faults formed in the central and the eastern part of the study area; (3) 28.4-23Ma, the subsidence area was further enlarged but mainly extended into the flanking area of the main rift zone; and (4) 23-15.5 Ma, the old faults ended and a lot of NW-trending slip faults were activate in the eastern part of the study area. As a result, the shape of depressions is NE-trending in the west but WE-trending in the east. Composite half-grabens are distributed mainly in the western and central CDQB, composite symmetric or asymmetric grabens are focused in the eastern CDQB, and the transverse folds are observed exceptionally in the southeastern CDQB. Besides that, the deep and thermal structures are invoked to account for such deformation differences. The lithosphere of the eastern CDQB is very hot and thinned because of mantle upwelling and heating, composite symmetric grabens formed, but the lithosphere in the western sector is transitional from very hot to normal. Eventually, the tectonic development of the CDQB may be summarized into four stages with dominating influences, slab-pull of the Proto-South China Sea (45–32 Ma), rapid Indochina block extrusion together with NE-trending and uniform seafloor spreading in Northwest Sub-sea Basin (32–28.4Ma), slow Indochina block extrusion together with NS-trending Central South China Sea seafloor spreading(28.4-23Ma), and the lithospheric thermal cooling together with the NE-trending seafloor spreading and non-uniformly spreading rates in Southwest Sub-sea Basin (23-15.5Ma). Located at the intersection between NW-trending slip system and NE-trending rift system in the northern South China Sea, the Central Depression of Qiongdongnan Basin (CDQB) and adjacent areas embed critical information on Indochina block extrusion and South China Sea seafloor spreading. In this study, we systematically reveal the striking structural differences between the western and eastern CDQB from fault distribution, depression form, rifting pattern, fault activities and structure evolution. A semi-quantitative analysis of the fault cut-offs identifies four stages of rifting evolution: (1) 45–32 Ma, sparsely distributed NE-trending faults formed mainly in the western and the central part of the study area; (2) 32–28.4 Ma, the area influenced by NE-trending faulting was extended into the eastern part of the study area and some NW-trending faults formed in the central and the eastern part of the study area; (3) 28.4-23Ma, the subsidence area was further enlarged but mainly extended into the flanking area of the main rift zone; and (4) 23-15.5 Ma, the old faults ended and a lot of NW-trending slip faults were activate in the eastern part of the study area. As a result, the shape of depressions is NE-trending in the west but WE-trending in the east. Composite half-grabens are distributed mainly in the western and central CDQB, composite symmetric or asymmetric grabens are focused in the eastern CDQB, and the transverse folds are observed exceptionally in the southeastern CDQB. Besides that, the deep and thermal structures are invoked to account for such deformation differences. The lithosphere of the eastern CDQB is very hot and thinned because of mantle upwelling and heating, composite symmetric grabens formed, but the lithosphere in the western sector is transitional from very hot to normal. Eventually, the tectonic development of the CDQB may be summarized into four stages with dominating influences, slab-pull of the Proto-South China Sea (45–32 Ma), rapid Indochina block extrusion together with NE-trending and uniform seafloor spreading in Northwest Sub-sea Basin (32–28.4Ma), slow Indochina block extrusion together with NS-trending Central South China Sea seafloor spreading(28.4-23Ma), and the lithospheric thermal cooling together with the NE-trending seafloor spreading and non-uniformly spreading rates in Southwest Sub-sea Basin (23-15.5Ma). Panel_15362 Panel_15362 8:30 AM 8:30 AM

The Black Hills uplift and Powder River Basin are separated by the Black Hills (BHM) and Fanny Peak (FPM) monoclines that intersect about seven miles east of Newcastle, Wyoming. The northwest and north-south trends of these structures, combined with an assumed regional Laramide horizontal stress field oriented approximately N70°E, suggests possible high-angle, oblique movement for basement faults that form the cores of these structures. A previous study focused on the geometry of structures within the monoclines and related them to features formed in a strike-slip environment, e.g. restraining bends, in-line anticlines, oblique faults and lenses such as the Newcastle terrace. To test the idea of a strike slip component, this study utilizes the kinematics of mesoscopic faults and joint data collected along the monoclines and manipulated in fault kinematic software (FaultKin 6). Preliminary results show a minor clockwise, eastward rotation of maximum compressive stress from N25°E to N45°E along the Black Hills monocline from west of the Newcastle terrace to the intersection of the BHM and FPM. Conjugate fault orientations suggest pre- to syn-tectonic formation of two thrust fault systems with dips which were subsequently rotated with bedding during rotation of the sedimentary layers. The intersection of monoclines of this magnitude is rare in the Rocky Mountains allowing for this research to add to the current knowledge of Laramide tectonics and to help further reconstruct the tectonic evolution of the Black Hills uplift. The Black Hills uplift and Powder River Basin are separated by the Black Hills (BHM) and Fanny Peak (FPM) monoclines that intersect about seven miles east of Newcastle, Wyoming. The northwest and north-south trends of these structures, combined with an assumed regional Laramide horizontal stress field oriented approximately N70°E, suggests possible high-angle, oblique movement for basement faults that form the cores of these structures. A previous study focused on the geometry of structures within the monoclines and related them to features formed in a strike-slip environment, e.g. restraining bends, in-line anticlines, oblique faults and lenses such as the Newcastle terrace. To test the idea of a strike slip component, this study utilizes the kinematics of mesoscopic faults and joint data collected along the monoclines and manipulated in fault kinematic software (FaultKin 6). Preliminary results show a minor clockwise, eastward rotation of maximum compressive stress from N25°E to N45°E along the Black Hills monocline from west of the Newcastle terrace to the intersection of the BHM and FPM. Conjugate fault orientations suggest pre- to syn-tectonic formation of two thrust fault systems with dips which were subsequently rotated with bedding during rotation of the sedimentary layers. The intersection of monoclines of this magnitude is rare in the Rocky Mountains allowing for this research to add to the current knowledge of Laramide tectonics and to help further reconstruct the tectonic evolution of the Black Hills uplift. Panel_15359 Panel_15359 8:30 AM 8:30 AM

The evolution of rift fault networks is typically associated with changes in the size, density and throw characteristics of constituent faults. Many studies have statistically analysed such changes to determine how strain is accommodated across fault networks through time. Although useful, such analyses neglect to incorporate the arrangement of, and relationships between, faults in the network, that is, the network topology. As such, changes in fault intersection type and frequency that occur in evolving networks, aspects that become increasingly critical in networks with faults sets of different orientations, have not previously been explored. Analysis of fault network topology has previously been applied to final fault networks with the aim of understanding fault connectivity and fluid flow in a ‘static’ sense. These studies divide the network into nodes and branches. Nodes are classified as either intersections between faults or free fault tips, whereas branches represent portions of the faults in between nodes and are classified according to the degree of connectivity to other branches. The topology of a given network is determined by plotting the total number and ratio of different node or branch types on ternary plots. Here we build on this approach by introducing the concept of ‘dynamic’ topology, that is, quantifying changes in the topology of a given network through time. In particular, we assess if: i) ‘dynamic’ topology can elucidate trends as a given fault network evolves; and ii) rifts of different types (e.g. single phase rifts, multiphase rifts etc) have distinctive evolutionary pathways. To achieve these aims we constrain and compare topology data from sequential plan view fault maps from physical models of different rift types. Physical model outputs are ideal for this study as map view fault intersections are well imaged and boundary conditions controlling the formation of the fault networks are tightly-constrained. We then test the applicability of ‘dynamic’ topology to natural fault systems, applying the approach to seismically imaged natural fault networks. Our results indicate: (1) ‘dynamic’ topology can be applied to fault networks from rifts with different modes of formation; (2) as fault networks mature there are marked changes in intersection type and frequency, along with overall increases in fault connectivity that are captured in ternary plots; and, strikingly, (3)) rifts of different types have distinctive evolutionary pathways. The evolution of rift fault networks is typically associated with changes in the size, density and throw characteristics of constituent faults. Many studies have statistically analysed such changes to determine how strain is accommodated across fault networks through time. Although useful, such analyses neglect to incorporate the arrangement of, and relationships between, faults in the network, that is, the network topology. As such, changes in fault intersection type and frequency that occur in evolving networks, aspects that become increasingly critical in networks with faults sets of different orientations, have not previously been explored. Analysis of fault network topology has previously been applied to final fault networks with the aim of understanding fault connectivity and fluid flow in a ‘static’ sense. These studies divide the network into nodes and branches. Nodes are classified as either intersections between faults or free fault tips, whereas branches represent portions of the faults in between nodes and are classified according to the degree of connectivity to other branches. The topology of a given network is determined by plotting the total number and ratio of different node or branch types on ternary plots. Here we build on this approach by introducing the concept of ‘dynamic’ topology, that is, quantifying changes in the topology of a given network through time. In particular, we assess if: i) ‘dynamic’ topology can elucidate trends as a given fault network evolves; and ii) rifts of different types (e.g. single phase rifts, multiphase rifts etc) have distinctive evolutionary pathways. To achieve these aims we constrain and compare topology data from sequential plan view fault maps from physical models of different rift types. Physical model outputs are ideal for this study as map view fault intersections are well imaged and boundary conditions controlling the formation of the fault networks are tightly-constrained. We then test the applicability of ‘dynamic’ topology to natural fault systems, applying the approach to seismically imaged natural fault networks. Our results indicate: (1) ‘dynamic’ topology can be applied to fault networks from rifts with different modes of formation; (2) as fault networks mature there are marked changes in intersection type and frequency, along with overall increases in fault connectivity that are captured in ternary plots; and, strikingly, (3)) rifts of different types have distinctive evolutionary pathways. Panel_15353 Panel_15353 8:30 AM 8:30 AM

Rift basins and passive margins continue to be significant targets for hydrocarbon exploration. Modern, active rift basins allow us to closely examine the evolution of structural traps in such settings. The Afar region of east Africa is the only sub-aerial exposure of a rift-rift-rift triple junction, and thus provides a rare view of the final stages of continental break-up. In the Afar, the East African rift meets the Red Sea and Gulf of Aden mid-ocean ridge rift propagators. Here, the ridges do not link discretely; rather diffuse normal faulting with some minor components of strike slip faulting accommodates extension between the overlapping rift propagators. All Quaternary deformation dissects extensive flood basalts of the 1 – 4 Ma Afar Stratoid Basalt series, such that minimum estimates of fault displacement can be easily determined by examining vertical offsets of the relict stratoid surface. One question that we seek to address in the Afar rift is the contribution of small faults to the overall extensional budget of the region. The contribution of large faults has been studied in past decades, but as faulting is very diffuse in this region, the contribution of small faults cannot be ignored. Fault displacement and length scaling relations provide a means of assessing the bulk strain and fault density in a rift basin. To examine fault growth and fault scaling relationships, we analyzed a set of stereographic panchromatic and orthorectified multispectral images. The stereographic images were processed into a 5 m DEM, which was used with the panchromatic and multispectral images were used as basis for mapping in ArcGIS. Once mapped, the fault traces were analyzed using a script in ArcGIS, with fault throws being calculated along the length of each fault. This analysis shows that fault maximum throw in Dobe graben scales proportionally to fault length following a power law. Additionally, fault length appears to follow a power law distribution. Previous work has shown that fault length follows an exponential distribution in regions experiencing high amounts of strain (e.g. mid ocean ridges; ? > 8%), while following a power law distribution in regions of lesser strain. Further mapping and statistical analysis should help pinpoint the transition between largely exponentially distributed fault length in the hyperextended Asal rift with power law fault scaling in the central Afar rift and Main Ethiopian Rift. Rift basins and passive margins continue to be significant targets for hydrocarbon exploration. Modern, active rift basins allow us to closely examine the evolution of structural traps in such settings. The Afar region of east Africa is the only sub-aerial exposure of a rift-rift-rift triple junction, and thus provides a rare view of the final stages of continental break-up. In the Afar, the East African rift meets the Red Sea and Gulf of Aden mid-ocean ridge rift propagators. Here, the ridges do not link discretely; rather diffuse normal faulting with some minor components of strike slip faulting accommodates extension between the overlapping rift propagators. All Quaternary deformation dissects extensive flood basalts of the 1 – 4 Ma Afar Stratoid Basalt series, such that minimum estimates of fault displacement can be easily determined by examining vertical offsets of the relict stratoid surface. One question that we seek to address in the Afar rift is the contribution of small faults to the overall extensional budget of the region. The contribution of large faults has been studied in past decades, but as faulting is very diffuse in this region, the contribution of small faults cannot be ignored. Fault displacement and length scaling relations provide a means of assessing the bulk strain and fault density in a rift basin. To examine fault growth and fault scaling relationships, we analyzed a set of stereographic panchromatic and orthorectified multispectral images. The stereographic images were processed into a 5 m DEM, which was used with the panchromatic and multispectral images were used as basis for mapping in ArcGIS. Once mapped, the fault traces were analyzed using a script in ArcGIS, with fault throws being calculated along the length of each fault. This analysis shows that fault maximum throw in Dobe graben scales proportionally to fault length following a power law. Additionally, fault length appears to follow a power law distribution. Previous work has shown that fault length follows an exponential distribution in regions experiencing high amounts of strain (e.g. mid ocean ridges; ? > 8%), while following a power law distribution in regions of lesser strain. Further mapping and statistical analysis should help pinpoint the transition between largely exponentially distributed fault length in the hyperextended Asal rift with power law fault scaling in the central Afar rift and Main Ethiopian Rift. Panel_15366 Panel_15366 8:30 AM 8:30 AM

Many rifts develop through multiphase extension; it can be difficult, however, to determine how strain is distributed during reactivation because structural and stratigraphic evidence associated with earlier rifting is often deeply buried. Using 2D and 3D seismic reflection and borehole data from the northern North Sea, we examine the style, magnitude and timing of reactivation of a pre-existing, Permian-Triassic (Rift Phase 1) fault array during a subsequent period of Middle Jurassic-to-Early Cretaceous (Rift Phase 2) extension. We show that Rift Phase 2 led to the formation of new N-S-striking faults close to the North Viking Graben, but did not initially reactivate pre-existing, seemingly optimally aligned Rift Phase 1 structures on the Horda Platform. We suggest that, at the beginning of Rift Phase 2, strain was focused in a zone of thermally weakened lithosphere associated with the Middle Jurassic North Sea thermal dome, rather than reactivating extant faults. Diachronous reactivation of the Permian-Triassic fault network did eventually occur, with those faults located closer to the Middle Jurassic-to-Early Cretaceous rift-axis reactivating earlier than those toward the eastern margin. In addition, faults on the southern Horda Platform reactive before those in the north, leading to both an eastward and northward migration in fault reactivation in this area through time. This diachroneity in the timing of fault reactivation may have been related to flexural down-bending as strain became focused within the North Viking Graben and/or the shifting of the locus of rifting from the North Sea to the proto-North Atlantic in the Early Cretaceous. Our study shows that the geometry and evolution of multiphase rifts is not only controlled by the orientation of the underlying fault network, but also by the thermal and rheological evolution of the lithosphere and variations in the regional stress field. Many rifts develop through multiphase extension; it can be difficult, however, to determine how strain is distributed during reactivation because structural and stratigraphic evidence associated with earlier rifting is often deeply buried. Using 2D and 3D seismic reflection and borehole data from the northern North Sea, we examine the style, magnitude and timing of reactivation of a pre-existing, Permian-Triassic (Rift Phase 1) fault array during a subsequent period of Middle Jurassic-to-Early Cretaceous (Rift Phase 2) extension. We show that Rift Phase 2 led to the formation of new N-S-striking faults close to the North Viking Graben, but did not initially reactivate pre-existing, seemingly optimally aligned Rift Phase 1 structures on the Horda Platform. We suggest that, at the beginning of Rift Phase 2, strain was focused in a zone of thermally weakened lithosphere associated with the Middle Jurassic North Sea thermal dome, rather than reactivating extant faults. Diachronous reactivation of the Permian-Triassic fault network did eventually occur, with those faults located closer to the Middle Jurassic-to-Early Cretaceous rift-axis reactivating earlier than those toward the eastern margin. In addition, faults on the southern Horda Platform reactive before those in the north, leading to both an eastward and northward migration in fault reactivation in this area through time. This diachroneity in the timing of fault reactivation may have been related to flexural down-bending as strain became focused within the North Viking Graben and/or the shifting of the locus of rifting from the North Sea to the proto-North Atlantic in the Early Cretaceous. Our study shows that the geometry and evolution of multiphase rifts is not only controlled by the orientation of the underlying fault network, but also by the thermal and rheological evolution of the lithosphere and variations in the regional stress field. Panel_15361 Panel_15361 8:30 AM 8:30 AM

Panel_14474 Panel_14474 8:30 AM 5:00 PM

The Miocene Monterey Formation is the principle petroleum source rock in California. The unit is characterized by fine-grained carbonate, phosphatic, and siliceous rocks of diatomaceous origin, deposited in silled, oxygen-poor basins. It is generally bounded both below and above by coarse-grained clastic rocks, preserving the history of basin formation, fill, and uplift. Extensional tectonics related to migration of the present-day Mendocino Triple Junction and development of the strike-slip San Andreas Fault is thought to be the primary tectonic driver of basin formation. In many basins, releasing bends or stepovers on strike-slip fault systems appear to play a large role in controlling sedimentation, while near the classic Santa Barbara outcrops, there is the additional influence of vertical-axis block rotation. Although the Monterey Formation is widely thought of as a single unit, previous work suggests variations to this framework. The unit is diachronous, with the timing of the transition from calcareous to siliceous facies varying from basin to basin. In addition, the unit thickness and lithological facies vary over short distances. It is likely that tectonics has a strong influence on these sedimentary characteristics, but it is not clear to what degree due to the limited understanding of the evolution of the geometry of basin-bounding strike-slip faults. The Monterey Formation exposed along the eastern flank of Santa Lucia Range, west of the Salinas Valley, may be a good location to test models of strike-slip basin formation. Along this trend, the Monterey Formation can be mapped as a continuous unit extending from Monterey southward toward Santa Maria. However, previous workers have noted that the base of the formation is diachronous along strike, there is evidence of rapid subsidence and uplift, and the unit contains large facies variations over short distances. These features are not consistent with simple models of releasing bend evolution. Instead, we suggest that instead of static releasing bends or step-overs, a more dynamic model involving migrating releasing bends, or releasing bends that evolve into restraining bends, may be able to better explain the sedimentary record of these basins. Migrating releasing bends allow for depocenter migration and extinction that may better explain the sedimentary variability within the Monterey Formation of the Santa Lucia Range. The Miocene Monterey Formation is the principle petroleum source rock in California. The unit is characterized by fine-grained carbonate, phosphatic, and siliceous rocks of diatomaceous origin, deposited in silled, oxygen-poor basins. It is generally bounded both below and above by coarse-grained clastic rocks, preserving the history of basin formation, fill, and uplift. Extensional tectonics related to migration of the present-day Mendocino Triple Junction and development of the strike-slip San Andreas Fault is thought to be the primary tectonic driver of basin formation. In many basins, releasing bends or stepovers on strike-slip fault systems appear to play a large role in controlling sedimentation, while near the classic Santa Barbara outcrops, there is the additional influence of vertical-axis block rotation. Although the Monterey Formation is widely thought of as a single unit, previous work suggests variations to this framework. The unit is diachronous, with the timing of the transition from calcareous to siliceous facies varying from basin to basin. In addition, the unit thickness and lithological facies vary over short distances. It is likely that tectonics has a strong influence on these sedimentary characteristics, but it is not clear to what degree due to the limited understanding of the evolution of the geometry of basin-bounding strike-slip faults. The Monterey Formation exposed along the eastern flank of Santa Lucia Range, west of the Salinas Valley, may be a good location to test models of strike-slip basin formation. Along this trend, the Monterey Formation can be mapped as a continuous unit extending from Monterey southward toward Santa Maria. However, previous workers have noted that the base of the formation is diachronous along strike, there is evidence of rapid subsidence and uplift, and the unit contains large facies variations over short distances. These features are not consistent with simple models of releasing bend evolution. Instead, we suggest that instead of static releasing bends or step-overs, a more dynamic model involving migrating releasing bends, or releasing bends that evolve into restraining bends, may be able to better explain the sedimentary record of these basins. Migrating releasing bends allow for depocenter migration and extinction that may better explain the sedimentary variability within the Monterey Formation of the Santa Lucia Range. Panel_15382 Panel_15382 8:30 AM 5:00 PM

The Fort Worth Basin in north-central Texas is a foreland basin of the Ouachita orogeny formed by the oblique collision of the Laurentia and Gondwana continents during the late Paleozoic. Although current studies on the Fort Worth Basin focus mainly on unconventional hydrocarbon exploration and production, how the tectonic evolution of the basin has controlled the hydrocarbon maturation has not been well understood. Here we study the late Paleozoic evolution of sedimentation patterns in the Fort Worth Basin by correlating well logs and reconstructing isopach and structure maps. Our results show that the tectonic uplift of the Muenster Arch to the northeast of the basin and the Ouachita thrust belt to the east of the basin influenced the subsidence of the basin as early as the middle-late Mississippian, and caused the middle Mississippian-early middle Pennsylvanian strata thickening toward the two structures. The Ouachita thrust belt became the primary tectonic load of the basin by the late middle Pennsylvanian when the depocenter shifted to the east part of the basin. We then model the one-dimensional and two-dimensional subsidence histories of the Fort Worth Basin during the Paleozoic, and constrain its dynamic relationship to the basin-bounding Ouachita thrust belt. Because the latest Paleozoic-Cenozoic strata have been largely eroded in the region, which adds uncertainty to strata decompaction and subsidence reconstruction, we use Petromod 1D to conduct thermal maturation modeling in order to constrain the post-Paleozoic burial and exhumation histories by matching the modeled vitrinite reflectance with measured vitrinite reflectance along several depth profiles in the basin. Our thermal maturation modeling results show that the northeast part of the basin experienced a total of 6.5 km of subsidence during the Pennsylvanian and Permian, suggesting the flexural subsidence of the Fort Worth Basin continued to the Permian in response to the continued propagation of the Ouachita thrust belt. The propagation of the Ouachita thrust belt also caused subsidence acceleration of the basin during the middle Pennsylvanian-Permian, which then controlled hydrocarbon maturation of the Mississippian and Pennsylvanian sources rocks. This study advances our understanding to the tectonic control on hydrocarbon maturation in the Fort Worth Basin. The Fort Worth Basin in north-central Texas is a foreland basin of the Ouachita orogeny formed by the oblique collision of the Laurentia and Gondwana continents during the late Paleozoic. Although current studies on the Fort Worth Basin focus mainly on unconventional hydrocarbon exploration and production, how the tectonic evolution of the basin has controlled the hydrocarbon maturation has not been well understood. Here we study the late Paleozoic evolution of sedimentation patterns in the Fort Worth Basin by correlating well logs and reconstructing isopach and structure maps. Our results show that the tectonic uplift of the Muenster Arch to the northeast of the basin and the Ouachita thrust belt to the east of the basin influenced the subsidence of the basin as early as the middle-late Mississippian, and caused the middle Mississippian-early middle Pennsylvanian strata thickening toward the two structures. The Ouachita thrust belt became the primary tectonic load of the basin by the late middle Pennsylvanian when the depocenter shifted to the east part of the basin. We then model the one-dimensional and two-dimensional subsidence histories of the Fort Worth Basin during the Paleozoic, and constrain its dynamic relationship to the basin-bounding Ouachita thrust belt. Because the latest Paleozoic-Cenozoic strata have been largely eroded in the region, which adds uncertainty to strata decompaction and subsidence reconstruction, we use Petromod 1D to conduct thermal maturation modeling in order to constrain the post-Paleozoic burial and exhumation histories by matching the modeled vitrinite reflectance with measured vitrinite reflectance along several depth profiles in the basin. Our thermal maturation modeling results show that the northeast part of the basin experienced a total of 6.5 km of subsidence during the Pennsylvanian and Permian, suggesting the flexural subsidence of the Fort Worth Basin continued to the Permian in response to the continued propagation of the Ouachita thrust belt. The propagation of the Ouachita thrust belt also caused subsidence acceleration of the basin during the middle Pennsylvanian-Permian, which then controlled hydrocarbon maturation of the Mississippian and Pennsylvanian sources rocks. This study advances our understanding to the tectonic control on hydrocarbon maturation in the Fort Worth Basin. Panel_15389 Panel_15389 8:30 AM 5:00 PM

Continental rifts commonly undergo multiple phases of rifting, with variations in both the rate and orientation of extension through time. Physical analogue experiments have demonstrated that the fault network developed during the initial rift phase influences subsequent fault populations. However, the full 3D geometry, evolution and interaction of fault networks are difficult to constrain from such models. A 3D discrete element model is employed to compare the evolution of normal fault networks in multi-phase rift environments with networks developed during a single rift phase. Faults are defined as an accumulation of broken bonds in the brittle layer, and their location, throw and interaction are recorded through time. Thus incremental fault displacement and geometry and the 4D evolution of the fault network can be examined. We investigate how the maturity of an initial normal fault network impacts fault network evolution and geometry during a second rift phase. We examine how strongly the presence of Phase I structures controls the initiation and localization of subsequent structures by setting secondary extension directions at 30, 45 and 60 degrees to the initial phase, and varying the length of Phase I relative to Phase II. Extension in the initial rift phase results in conjugate fault sets that nucleate and organize themselves by segment growth, interaction and linkage into co-linear fault zones. Increased extension leads to a preferred dip polarity and crustal-scale half grabens. The degree of development of this first-phase fault network strongly influences the second phase fault geometry and evolution. A small amount of Phase I extension promotes fault orientations in Phase II that are initially controlled by the orientation of Phase I before Phase II dominates. An intermediate level of Phase I extension results in complex Phase II fault geometries where reactivation of Phase I faults is common and new faults form to accommodate displacement on earlier faults. Sigmoidal planform fault geometries develop, with complex, zig-zag and rhomboidal fault patterns. A mature initial fault network results in Phase II being dominated by, and deformation localized onto, Phase I faults. Domains dominated by new Phase II faults occur where the density of Phase I faults is low. In all models, fault geometry shows clear variation with depth - faults become less segmented and are better represented by the Phase I orientation at deeper structural levels. Continental rifts commonly undergo multiple phases of rifting, with variations in both the rate and orientation of extension through time. Physical analogue experiments have demonstrated that the fault network developed during the initial rift phase influences subsequent fault populations. However, the full 3D geometry, evolution and interaction of fault networks are difficult to constrain from such models. A 3D discrete element model is employed to compare the evolution of normal fault networks in multi-phase rift environments with networks developed during a single rift phase. Faults are defined as an accumulation of broken bonds in the brittle layer, and their location, throw and interaction are recorded through time. Thus incremental fault displacement and geometry and the 4D evolution of the fault network can be examined. We investigate how the maturity of an initial normal fault network impacts fault network evolution and geometry during a second rift phase. We examine how strongly the presence of Phase I structures controls the initiation and localization of subsequent structures by setting secondary extension directions at 30, 45 and 60 degrees to the initial phase, and varying the length of Phase I relative to Phase II. Extension in the initial rift phase results in conjugate fault sets that nucleate and organize themselves by segment growth, interaction and linkage into co-linear fault zones. Increased extension leads to a preferred dip polarity and crustal-scale half grabens. The degree of development of this first-phase fault network strongly influences the second phase fault geometry and evolution. A small amount of Phase I extension promotes fault orientations in Phase II that are initially controlled by the orientation of Phase I before Phase II dominates. An intermediate level of Phase I extension results in complex Phase II fault geometries where reactivation of Phase I faults is common and new faults form to accommodate displacement on earlier faults. Sigmoidal planform fault geometries develop, with complex, zig-zag and rhomboidal fault patterns. A mature initial fault network results in Phase II being dominated by, and deformation localized onto, Phase I faults. Domains dominated by new Phase II faults occur where the density of Phase I faults is low. In all models, fault geometry shows clear variation with depth - faults become less segmented and are better represented by the Phase I orientation at deeper structural levels. Panel_15381 Panel_15381 8:30 AM 5:00 PM

Outcrop analogues are often used to aid understanding of subsurface rock geometries and deformation. For fold-thrust belts field analogues play an important role in prediction of fold-thrust forelimb structures, that are difficult to image seismically. Understanding the continuity of strata in forelimbs and the extent of damage is critical for determining trap geometry and viability. Further, the extent of deformation in carbonate reservoir formations may inhibit or enhance flow within the reservoir, with implications for the petroleum charge of, and production from carbonate reservoirs. Kinematic forward models of fold thrust systems (e.g. fault-bend fold, trishear) provide end-members for the possible kinematic evolution of fold-thrust structures. These kinematic models are however very limited, matching the broad geometries of some structures, but do not effectively predict smaller scale deformation features, or the damage seen in many field analogues. The French sub-Alpine chain has been used as an analogue for carbonate fold-thrust systems. The chain is dominated by a 200-300m thick Urgonian limestone key bed, beneath which carbonates, of different geomechanical characteristics, are inter-bedded with more ductile shale units. 3D models of large tracts of the fold-thrust belt have been created from satellite, map, well and field data. Analysis of the 3D models has been combined with detailed studies of specific fold-thrust forelimb outcrops. At these forelimb field-sites investigation of the main deformation mechanisms and formation damage at a range of scales has been made. The field studies are compared with kinematic model predictions of deformation based on the 3D models. The mechanical stratigraphy provides difficulties in predicting structures and structural styles using simple kinematic models. Our combined modeling and field data raises issues in determining deformation mechanisms in carbonate fold thrust belts and whether damage and fractures in fold-thrust fore-limbs can be predicted. Outcrop analogues are often used to aid understanding of subsurface rock geometries and deformation. For fold-thrust belts field analogues play an important role in prediction of fold-thrust forelimb structures, that are difficult to image seismically. Understanding the continuity of strata in forelimbs and the extent of damage is critical for determining trap geometry and viability. Further, the extent of deformation in carbonate reservoir formations may inhibit or enhance flow within the reservoir, with implications for the petroleum charge of, and production from carbonate reservoirs. Kinematic forward models of fold thrust systems (e.g. fault-bend fold, trishear) provide end-members for the possible kinematic evolution of fold-thrust structures. These kinematic models are however very limited, matching the broad geometries of some structures, but do not effectively predict smaller scale deformation features, or the damage seen in many field analogues. The French sub-Alpine chain has been used as an analogue for carbonate fold-thrust systems. The chain is dominated by a 200-300m thick Urgonian limestone key bed, beneath which carbonates, of different geomechanical characteristics, are inter-bedded with more ductile shale units. 3D models of large tracts of the fold-thrust belt have been created from satellite, map, well and field data. Analysis of the 3D models has been combined with detailed studies of specific fold-thrust forelimb outcrops. At these forelimb field-sites investigation of the main deformation mechanisms and formation damage at a range of scales has been made. The field studies are compared with kinematic model predictions of deformation based on the 3D models. The mechanical stratigraphy provides difficulties in predicting structures and structural styles using simple kinematic models. Our combined modeling and field data raises issues in determining deformation mechanisms in carbonate fold thrust belts and whether damage and fractures in fold-thrust fore-limbs can be predicted. Panel_15388 Panel_15388 8:30 AM 5:00 PM

We review opening models for the Gulf of Mexico (GOM) in light of our own studies of deep-penetration seismic reflection data in the eastern GOM. Most groups agree that the first phase of syn-rift GOM opening is late Triassic-early Jurassic (235-174 Ma) in age, NW-to-SE in extension direction, and responsible for creating a broad zone of thinned, continental crust along the northern margin of the GOM and underlying the northern salt basins of Texas, Louisiana and Mississippi. This Late Triassic-early Jurassic rift zone is an along-strike continuation of Triassic rifts present along the eastern margin of North America - but in the northern GOM case failed to culminate in production of a parallel and contiguous zone of oceanic crust across the broad northern GOM. Progress has been slow in understanding the early history and crustal structure of this area in the GOM due to the obscuring presence of an overlying sag basin of post-early Jurassic age filled by 3-4 km of depositional salt (now remobilized). The second and much better understood phase of GOM opening is late Jurassic (156-145 Ma) and post-salt in age and formed a large expanse of salt-free, Jurassic oceanic crust underlying the deepwater GOM shared by the US, Mexico and Cuba. This second late Jurassic opening phase occurred along a highly arcuate slow spreading ridge now well imaged on basin-wide, satellite gravity maps. We have georeferenced our grid of deep-penetration seismic and well data in the EGOM along with recent refraction studies to both ground-truth these satellite images and provide details of the early breakup and separation. Our eastern and NE GOM continent-ocean boundary defined by deep seismic profiles is within 20 km of that inferred from satellite gravity. We have used the shape of the satellite-imaged fracture zones in the Mexican GOM to improve the pole position for this second phase of GOM opening which is located in the Straits of Florida. This pole restores trends of crustal fabric in Florida and the Yucatan Peninsula seen on gravity and magnetic maps to pre-rotation parallelism. We use this pole to create a kinematic plate model for the second phase of GOM opening that respects all available seismic reflection, refraction, well, and satellite imagery. We review opening models for the Gulf of Mexico (GOM) in light of our own studies of deep-penetration seismic reflection data in the eastern GOM. Most groups agree that the first phase of syn-rift GOM opening is late Triassic-early Jurassic (235-174 Ma) in age, NW-to-SE in extension direction, and responsible for creating a broad zone of thinned, continental crust along the northern margin of the GOM and underlying the northern salt basins of Texas, Louisiana and Mississippi. This Late Triassic-early Jurassic rift zone is an along-strike continuation of Triassic rifts present along the eastern margin of North America - but in the northern GOM case failed to culminate in production of a parallel and contiguous zone of oceanic crust across the broad northern GOM. Progress has been slow in understanding the early history and crustal structure of this area in the GOM due to the obscuring presence of an overlying sag basin of post-early Jurassic age filled by 3-4 km of depositional salt (now remobilized). The second and much better understood phase of GOM opening is late Jurassic (156-145 Ma) and post-salt in age and formed a large expanse of salt-free, Jurassic oceanic crust underlying the deepwater GOM shared by the US, Mexico and Cuba. This second late Jurassic opening phase occurred along a highly arcuate slow spreading ridge now well imaged on basin-wide, satellite gravity maps. We have georeferenced our grid of deep-penetration seismic and well data in the EGOM along with recent refraction studies to both ground-truth these satellite images and provide details of the early breakup and separation. Our eastern and NE GOM continent-ocean boundary defined by deep seismic profiles is within 20 km of that inferred from satellite gravity. We have used the shape of the satellite-imaged fracture zones in the Mexican GOM to improve the pole position for this second phase of GOM opening which is located in the Straits of Florida. This pole restores trends of crustal fabric in Florida and the Yucatan Peninsula seen on gravity and magnetic maps to pre-rotation parallelism. We use this pole to create a kinematic plate model for the second phase of GOM opening that respects all available seismic reflection, refraction, well, and satellite imagery. Panel_15376 Panel_15376 8:30 AM 5:00 PM

The reactivation potential of pre-existing basement structures affects the geometry of subsequent deformation structures and location of some hydrocarbon traps. Potential hydrocarbon migration routes and their effectiveness, as well as the lateral extents of traps, are heavily influenced by faults and fractures, the intensity of which may be altered by reactivation. The Sawtooth Range, Montana, has been used as a study area. A model for the development of structures close to the Augusta Syncline in the Sawtooth Range is being developed using: 1) a compilation of the basement structures of the belt based on analysis of gravity and aeromagnetic anomalies, seismic data and well logs where available, and 2) a compilation of the surface deformation structures of the belt based on remote sensing images and field data indicating stress directions and age relationships. The final result will be a conceptual model based on the interpretation of the two previous maps including statistical correlations of data and development of balanced cross-sections. Preliminary results indicate that the change in orientation of surface thrust faults observed in the Sawtooth Range, from a NNW-SSE orientation near the Gibson Reservoir to a WNW-ESE trend near Haystack Butte, correlates with the Scapegoat-Bannatyne trend, a pre-existing structure lying within the Great Falls Tectonic Zone. The Scapegoat-Bannatyne trend may be composed of up to 4 NE-SW oriented, en-echelon basement strike-slip faults reactivated from the Proterozoic suture zone between the Medicine Hat and Wyoming Cratons. These multiple reactivated features of deformation influence fracture intensity both at depth and at the surface. This is indicated by the variations between along-dip versus along-strike folding and fracturing observed at the surface. An understanding of these reactivation relationships can lead to more successful unconventional exploration in that an analysis of fault migration or sealing potential can be determined. The fracture intensity will determine the effectiveness of the faults as a hydrocarbon seal versus a migration pathway. In addition, an assessment of the pre-existing structures with respect to the present-day stress direction will contribute to the understanding of which fracture sets will be open or closed and enhance the design of hydrofracturing treatments. The reactivation potential of pre-existing basement structures affects the geometry of subsequent deformation structures and location of some hydrocarbon traps. Potential hydrocarbon migration routes and their effectiveness, as well as the lateral extents of traps, are heavily influenced by faults and fractures, the intensity of which may be altered by reactivation. The Sawtooth Range, Montana, has been used as a study area. A model for the development of structures close to the Augusta Syncline in the Sawtooth Range is being developed using: 1) a compilation of the basement structures of the belt based on analysis of gravity and aeromagnetic anomalies, seismic data and well logs where available, and 2) a compilation of the surface deformation structures of the belt based on remote sensing images and field data indicating stress directions and age relationships. The final result will be a conceptual model based on the interpretation of the two previous maps including statistical correlations of data and development of balanced cross-sections. Preliminary results indicate that the change in orientation of surface thrust faults observed in the Sawtooth Range, from a NNW-SSE orientation near the Gibson Reservoir to a WNW-ESE trend near Haystack Butte, correlates with the Scapegoat-Bannatyne trend, a pre-existing structure lying within the Great Falls Tectonic Zone. The Scapegoat-Bannatyne trend may be composed of up to 4 NE-SW oriented, en-echelon basement strike-slip faults reactivated from the Proterozoic suture zone between the Medicine Hat and Wyoming Cratons. These multiple reactivated features of deformation influence fracture intensity both at depth and at the surface. This is indicated by the variations between along-dip versus along-strike folding and fracturing observed at the surface. An understanding of these reactivation relationships can lead to more successful unconventional exploration in that an analysis of fault migration or sealing potential can be determined. The fracture intensity will determine the effectiveness of the faults as a hydrocarbon seal versus a migration pathway. In addition, an assessment of the pre-existing structures with respect to the present-day stress direction will contribute to the understanding of which fracture sets will be open or closed and enhance the design of hydrofracturing treatments. Panel_15378 Panel_15378 8:30 AM 5:00 PM

Recent studies of the South Atlantic oceanic fracture zones indicate that the timing of changes in their azimuth during continental breakup can be linked to the timing of the regional unconformities in the circum-South Atlantic continental blocks. However, it is not yet clear if and how the timing of other geologic events, such as tectonic inversion and igneous activity, are linked to changes in the oceanic fracture azimuthal geometry. Here, we attempt to link plate boundary and plate interior geodynamics associated with South Atlantic opening by focusing on the tectono-stratigraphic evolution of the Bornu Basin, NE Nigeria, one of several continental rifts located in the West African Rift System. More specifically, we use 2D and 3D time-migrated seismic reflection, borehole, field and geochemical data to determine how plate margin processes impact normal fault growth, inversion, stratigraphic patterns, igneous activity and petroleum systems development within interior basins. We demonstrate that key tectonic events in the basin were broadly time equivalent to changes in the azimuth of the major oceanic fracture zones. For example, the timing of rift initiation in Bornu Basin during the Early Aptian correlates with the early change in azimuth observed in Kane Oceanic Fracture Zone (KFZ). The subsequent change in azimuth of the KFZ during the Turonian was coeval with the onset of basin shortening and inversion, with the formation of a major regional unconformity corresponding to another major change in azimuth of the KFZ in the Late Maastrichtian. Furthermore, the three main phases of igneous activity in the basin in the Early Cretaceous, Late Cretaceous and Tertiary correlate with the timing of the major azimuth changes observed in the Kane, Fifteen Twenty and St. Paul Oceanic fracture zones. Our study highlights that the geodynamics of the South Atlantic Ocean opening during continental break up was not only expressed by changes in the azimuth of the oceanic fracture zones, but was also recorded in the surrounding, intra-plate continental rift basins. Furthermore, understanding of the timing of the normal fault inversion and igneous activity can help to minimize exploration risks associated with trap charging, reservoir quality and source rock hydrocarbon potential. Recent studies of the South Atlantic oceanic fracture zones indicate that the timing of changes in their azimuth during continental breakup can be linked to the timing of the regional unconformities in the circum-South Atlantic continental blocks. However, it is not yet clear if and how the timing of other geologic events, such as tectonic inversion and igneous activity, are linked to changes in the oceanic fracture azimuthal geometry. Here, we attempt to link plate boundary and plate interior geodynamics associated with South Atlantic opening by focusing on the tectono-stratigraphic evolution of the Bornu Basin, NE Nigeria, one of several continental rifts located in the West African Rift System. More specifically, we use 2D and 3D time-migrated seismic reflection, borehole, field and geochemical data to determine how plate margin processes impact normal fault growth, inversion, stratigraphic patterns, igneous activity and petroleum systems development within interior basins. We demonstrate that key tectonic events in the basin were broadly time equivalent to changes in the azimuth of the major oceanic fracture zones. For example, the timing of rift initiation in Bornu Basin during the Early Aptian correlates with the early change in azimuth observed in Kane Oceanic Fracture Zone (KFZ). The subsequent change in azimuth of the KFZ during the Turonian was coeval with the onset of basin shortening and inversion, with the formation of a major regional unconformity corresponding to another major change in azimuth of the KFZ in the Late Maastrichtian. Furthermore, the three main phases of igneous activity in the basin in the Early Cretaceous, Late Cretaceous and Tertiary correlate with the timing of the major azimuth changes observed in the Kane, Fifteen Twenty and St. Paul Oceanic fracture zones. Our study highlights that the geodynamics of the South Atlantic Ocean opening during continental break up was not only expressed by changes in the azimuth of the oceanic fracture zones, but was also recorded in the surrounding, intra-plate continental rift basins. Furthermore, understanding of the timing of the normal fault inversion and igneous activity can help to minimize exploration risks associated with trap charging, reservoir quality and source rock hydrocarbon potential. Panel_15386 Panel_15386 8:30 AM 5:00 PM

Transfer zones between major rift basins are critical locations in rift architecture as they often form long lived structural features that are pervasive during lithospheric extension from rifting through into post-rift passive margins. Here we undertake a regional structural analysis of the Tanganyika-Rukwa-Malawi (TRM) system, which is located on the Western Branch of the East African Rift System (EARS). The TRM fault zone is a 1000 km long and 200 km wide zone that follows the trend of the Ubendian Orogeny Precambrian lineament. Additionally, the region is within rifted Permo-Triassic (Karoo) and Cretaceous rifting. Much debate has centered about the role of the Rukwa basin within this part of the EARS, specifically whether it forms a transfer between the en echelon troughs of the Tanganyika and Malawi Rifts; and whether it has opened in oblique or pure extension. Recent studies have highlighted the possibility of more than one orientation of rifting both within the Rukwa Rift and surrounding rift basins, and there is much potential for the inheritance from and reactivation of existing earlier rift faults. Although a number of studies have considered the evolution of each of these basins, these have tended to consider basins in isolation. In this study we integrate existing seismic reflection data with new high resolution reflection, Full Tensor Gradient and Digital Elevation Modelling data to construct a unified structural model of the TRM system. The structural model allows us to investigate a number of key parameters, including the distribution of strain across the system, the role of pre-existing fabrics on fault geometry, the distribution of volcanics and the role of stress obliquity on fault evolution. These findings provide a new understanding of the evolution of this area but also insights into the processes involved at transfer zones in both mature rift basins and passive margin settings. Transfer zones between major rift basins are critical locations in rift architecture as they often form long lived structural features that are pervasive during lithospheric extension from rifting through into post-rift passive margins. Here we undertake a regional structural analysis of the Tanganyika-Rukwa-Malawi (TRM) system, which is located on the Western Branch of the East African Rift System (EARS). The TRM fault zone is a 1000 km long and 200 km wide zone that follows the trend of the Ubendian Orogeny Precambrian lineament. Additionally, the region is within rifted Permo-Triassic (Karoo) and Cretaceous rifting. Much debate has centered about the role of the Rukwa basin within this part of the EARS, specifically whether it forms a transfer between the en echelon troughs of the Tanganyika and Malawi Rifts; and whether it has opened in oblique or pure extension. Recent studies have highlighted the possibility of more than one orientation of rifting both within the Rukwa Rift and surrounding rift basins, and there is much potential for the inheritance from and reactivation of existing earlier rift faults. Although a number of studies have considered the evolution of each of these basins, these have tended to consider basins in isolation. In this study we integrate existing seismic reflection data with new high resolution reflection, Full Tensor Gradient and Digital Elevation Modelling data to construct a unified structural model of the TRM system. The structural model allows us to investigate a number of key parameters, including the distribution of strain across the system, the role of pre-existing fabrics on fault geometry, the distribution of volcanics and the role of stress obliquity on fault evolution. These findings provide a new understanding of the evolution of this area but also insights into the processes involved at transfer zones in both mature rift basins and passive margin settings. Panel_15385 Panel_15385 8:30 AM 5:00 PM

Seismic imaging and resolution frequently present a critical issue in defining reservoir geometry and closure, greatly affecting estimated hydrocarbon volumes and well planning. This problem is compounded in compressional systems, where even normally seismically resolvable structures are frequently poorly imaged due to complex or steeply dipping strata. As a result, multiple geometric interpretations may be consistent with the available subsurface data. This study considers a suite of alternate interpretations for duplexes beneath the Nunchia Syncline of the frontal ranges of the Llanos Basin, Eastern Cordillera, Colombia. Seismic forward modelling is used to simulate these cases, varying structural configuration and pore fluid content, to gain further insight on effective interpretation strategies. Subsequently, synthetic volumes are compared to each other, and against the actual data to explore more subtle geometric changes in the forelimb of related fault propagation folds. We propose that utilising seismic forward modelling will assist in reducing interpretation uncertainty in these settings. Seismic imaging and resolution frequently present a critical issue in defining reservoir geometry and closure, greatly affecting estimated hydrocarbon volumes and well planning. This problem is compounded in compressional systems, where even normally seismically resolvable structures are frequently poorly imaged due to complex or steeply dipping strata. As a result, multiple geometric interpretations may be consistent with the available subsurface data. This study considers a suite of alternate interpretations for duplexes beneath the Nunchia Syncline of the frontal ranges of the Llanos Basin, Eastern Cordillera, Colombia. Seismic forward modelling is used to simulate these cases, varying structural configuration and pore fluid content, to gain further insight on effective interpretation strategies. Subsequently, synthetic volumes are compared to each other, and against the actual data to explore more subtle geometric changes in the forelimb of related fault propagation folds. We propose that utilising seismic forward modelling will assist in reducing interpretation uncertainty in these settings. Panel_15384 Panel_15384 8:30 AM 5:00 PM

The Cordillera Oriental of Colombia is a thick-skinned thrust-belt produced by Oligocene-recent inversion of a Jurassic-early Cretaceous rift followed by post-rift thermal subsidence and deposition of a Cretaceous marine sedimentary sequence. In the eastern foothills of the Cordillera Oriental thrust deformation transitions from a thick-skinned style to the thin-skinned style characterized by antiformal stack duplex overlying other thrust sheets. The formation of thrust-related structural traps, pulses of uplift and exhumation of the foothills thrust-belt over a period of 30 Ma is important to understand a known petroleum system with known discoveries since 1990’s totaling 1083 MBOE. Four balanced cross section illustrate the deformation of the Cretaceous Guadalupe formation, Paleocene Barco Formation and Eocene Mirador formation reservoir rocks at the Pauto, Florena and Huron producing fields. Along the southern areas through the Pauto and Volcanera fields, the south-dipping thrust faults have larger throws (4.8 km) but less folding and fewer thrust sheets. To the north thrust deformation increase with the appearance of more thrust sheets (50% of shortening) with less displacement on major faults (Yopal and Guaicaramo thrust faults). Axial planes of the Nunchia syncline and Monterralo anticline plunge southward showing that the basal detachment of the Nunchia syncline shallows in the north with many underlying thrust sheets which are all prospective traps and seals for hydrocarbons. Areas of likely reservoirs will less risk are proposed using the cross sections and its sequence of deformation. The Cordillera Oriental of Colombia is a thick-skinned thrust-belt produced by Oligocene-recent inversion of a Jurassic-early Cretaceous rift followed by post-rift thermal subsidence and deposition of a Cretaceous marine sedimentary sequence. In the eastern foothills of the Cordillera Oriental thrust deformation transitions from a thick-skinned style to the thin-skinned style characterized by antiformal stack duplex overlying other thrust sheets. The formation of thrust-related structural traps, pulses of uplift and exhumation of the foothills thrust-belt over a period of 30 Ma is important to understand a known petroleum system with known discoveries since 1990’s totaling 1083 MBOE. Four balanced cross section illustrate the deformation of the Cretaceous Guadalupe formation, Paleocene Barco Formation and Eocene Mirador formation reservoir rocks at the Pauto, Florena and Huron producing fields. Along the southern areas through the Pauto and Volcanera fields, the south-dipping thrust faults have larger throws (4.8 km) but less folding and fewer thrust sheets. To the north thrust deformation increase with the appearance of more thrust sheets (50% of shortening) with less displacement on major faults (Yopal and Guaicaramo thrust faults). Axial planes of the Nunchia syncline and Monterralo anticline plunge southward showing that the basal detachment of the Nunchia syncline shallows in the north with many underlying thrust sheets which are all prospective traps and seals for hydrocarbons. Areas of likely reservoirs will less risk are proposed using the cross sections and its sequence of deformation. Panel_15383 Panel_15383 8:30 AM 5:00 PM

An array of faults mapped at Marshall Mesa represent the southwestern exposure of a fault system interpreted as the result of either “listric growth faulting” or “decollement high-angle reverse faulting”. The faults crop out within the Late Cretaceous Fox Hills Sandstone and Laramie Formation in part of the Boulder-Weld coal field and have economic and environmental implications for sub-surface gas and coal reserves and the Laramie-Fox Hills aquifer in the Denver Basin. The listric growth faulting model interprets high-angle normal faults at the surface as the products of growth faulting developed in the delta-front environment that deposited the upper Pierre Shale through the lower Laramie Formation. Listric normal faults observed in seismic data within the uppermost Cretaceous are also interpreted to have spacial a relationship with NE-SW striking deep basement-controlled faults on the northeast projection of the Ralston shear zone. NE-SW striking faults also compartmentalize reservoirs within the nearby Wattenberg gas field. The decollement high-angle reverse faulting model interprets sub-surface faults along strike to the northeast of the mapped array as representing the leading edge of deformation of the upper Cretaceous sedimentary rocks along a bedding plane decollement within the upper Pierre Shale. This deformation has uplifted the Laramie-Fox Hills aquifer and repeated sections within the aquifer, locally increasing its thickness by nearly 75 meters. Detailed, integrated digital mapping of the exposed fault array at Marshall Mesa reveals a series of complex structural relationships that indicate both normal faulting and subsequent shortening, marked by folding and locally reverse faulting, plus inversion of earlier normal faults. A history of extension and growth faulting linked to down-dip contraction, with localized inversion reconciles the competing earlier interpretations and illustrates the advantages of integrating digital data collection with detailed field mapping and cross section restorations. An array of faults mapped at Marshall Mesa represent the southwestern exposure of a fault system interpreted as the result of either “listric growth faulting” or “decollement high-angle reverse faulting”. The faults crop out within the Late Cretaceous Fox Hills Sandstone and Laramie Formation in part of the Boulder-Weld coal field and have economic and environmental implications for sub-surface gas and coal reserves and the Laramie-Fox Hills aquifer in the Denver Basin. The listric growth faulting model interprets high-angle normal faults at the surface as the products of growth faulting developed in the delta-front environment that deposited the upper Pierre Shale through the lower Laramie Formation. Listric normal faults observed in seismic data within the uppermost Cretaceous are also interpreted to have spacial a relationship with NE-SW striking deep basement-controlled faults on the northeast projection of the Ralston shear zone. NE-SW striking faults also compartmentalize reservoirs within the nearby Wattenberg gas field. The decollement high-angle reverse faulting model interprets sub-surface faults along strike to the northeast of the mapped array as representing the leading edge of deformation of the upper Cretaceous sedimentary rocks along a bedding plane decollement within the upper Pierre Shale. This deformation has uplifted the Laramie-Fox Hills aquifer and repeated sections within the aquifer, locally increasing its thickness by nearly 75 meters. Detailed, integrated digital mapping of the exposed fault array at Marshall Mesa reveals a series of complex structural relationships that indicate both normal faulting and subsequent shortening, marked by folding and locally reverse faulting, plus inversion of earlier normal faults. A history of extension and growth faulting linked to down-dip contraction, with localized inversion reconciles the competing earlier interpretations and illustrates the advantages of integrating digital data collection with detailed field mapping and cross section restorations. Panel_15377 Panel_15377 8:30 AM 5:00 PM

Panel_14480 Panel_14480 8:30 AM 5:00 PM

Key onshore plays across the margin of the northern Gulf of Mexico are investigated on a new and unique mega-regional, PSDM seismic dataset that for the first time illustrates the full scope of play configuration and offers new approaches for the explorationist. The onshore dataset is unique as no other dataset like it exists on any margin in the world today. The seismic data consists of onshore strike and dip lines composited from over 470 segments of legacy onshore data that were reprocessed from field tapes, and connects to offshore, long offset, seismic surveys providing a view of the whole Gulf basin. The widely-spaced onshore seismic grid extends from the updip limit of the Louann Salt to the present-day shoreline, and from the South Texas/Mexico border to the Florida Panhandle. The grid clarifies the configuration and later Mesozoic structuring of the onshore basins and uplifts, the extent of older salt gravity sliding, and paleo-shelf edges in the Cotton Valley. New onshore strike lines show the Eagle Ford/Tuscaloosa onlap transgressive wedge in its entirety, and highlight the west to east chronostratigraphic relationships. The Cenomanian/Woodbine lowstand wedges and deeper water facies of fans filled into accommodation space created by a major collapse of the Mesozoic margins creating possible play areas that have been inadequately imaged due to the limited scope of previous datasets. The strike view shows 100 km wide, collapse fault complexes breaking apart the Cretaceous margins, and due to the size of these features, the mega-regional grid may provide new insight into Wilcox play opportunities as these sediments expanded to fill the faulted topography. Onshore tilted fault blocks involving Wilcox and Mesozoic sediments are numerous under a regional onshore allochthonous salt weld and provide prospective leads with overburden thicknesses and drilling depths comparable to the Wilcox deep water fold belt discoveries. Paleocene to Wilcox-age incised canyons occur around the margin and could provide plays against the canyon incisions into older rock, as well as new play ideas as these features could provide downdip conduits for lowstand fan sediments. Key onshore plays across the margin of the northern Gulf of Mexico are investigated on a new and unique mega-regional, PSDM seismic dataset that for the first time illustrates the full scope of play configuration and offers new approaches for the explorationist. The onshore dataset is unique as no other dataset like it exists on any margin in the world today. The seismic data consists of onshore strike and dip lines composited from over 470 segments of legacy onshore data that were reprocessed from field tapes, and connects to offshore, long offset, seismic surveys providing a view of the whole Gulf basin. The widely-spaced onshore seismic grid extends from the updip limit of the Louann Salt to the present-day shoreline, and from the South Texas/Mexico border to the Florida Panhandle. The grid clarifies the configuration and later Mesozoic structuring of the onshore basins and uplifts, the extent of older salt gravity sliding, and paleo-shelf edges in the Cotton Valley. New onshore strike lines show the Eagle Ford/Tuscaloosa onlap transgressive wedge in its entirety, and highlight the west to east chronostratigraphic relationships. The Cenomanian/Woodbine lowstand wedges and deeper water facies of fans filled into accommodation space created by a major collapse of the Mesozoic margins creating possible play areas that have been inadequately imaged due to the limited scope of previous datasets. The strike view shows 100 km wide, collapse fault complexes breaking apart the Cretaceous margins, and due to the size of these features, the mega-regional grid may provide new insight into Wilcox play opportunities as these sediments expanded to fill the faulted topography. Onshore tilted fault blocks involving Wilcox and Mesozoic sediments are numerous under a regional onshore allochthonous salt weld and provide prospective leads with overburden thicknesses and drilling depths comparable to the Wilcox deep water fold belt discoveries. Paleocene to Wilcox-age incised canyons occur around the margin and could provide plays against the canyon incisions into older rock, as well as new play ideas as these features could provide downdip conduits for lowstand fan sediments. Panel_15444 Panel_15444 8:30 AM 5:00 PM

Large volumes of intrusive igneous material associated with volcanic rift margins introduces significant uncertainty to both hydrocarbon exploration and subsequent prospectivity. Understanding the habit, emplacement and distribution of such material in the context of rift evolution is reduces this uncertainty and helps enhance our understanding the evolution of volcanic rift margins. The recent availability of high-quality 3D seismic data from the rift basins of the NE Atlantic Margin has enhanced our understanding of the 3D geometry and emplacement mechanisms of sill intrusions. Exactly how the characteristics and timing of these intrusions fit within the wider margin context is often overlooked. The West of Shetland area provides an insight into the process of volcanic rift interaction in a petroleum prospective area. Using multi-client 2D and 3D seismic data we place reservoir scale observations of sill morphology, size, distribution and sill-fault interactions within a wider basin context. We have identified three distinct sill facies through detailed 3D seismic interpretation and seismic attribute analysis, each show significant morphological variations and are emplaced within contrasting structural settings. Given the variations in sill size and frequency within each facies there are also implications for bulk regional intrusive magma distribution across the margin. We demonstrate that the style and volume of sill intrusion is heavily influenced by the large scale basin structure, the position along the volcanic margin and small scale structural heterogeneities. Large volumes of intrusive igneous material associated with volcanic rift margins introduces significant uncertainty to both hydrocarbon exploration and subsequent prospectivity. Understanding the habit, emplacement and distribution of such material in the context of rift evolution is reduces this uncertainty and helps enhance our understanding the evolution of volcanic rift margins. The recent availability of high-quality 3D seismic data from the rift basins of the NE Atlantic Margin has enhanced our understanding of the 3D geometry and emplacement mechanisms of sill intrusions. Exactly how the characteristics and timing of these intrusions fit within the wider margin context is often overlooked. The West of Shetland area provides an insight into the process of volcanic rift interaction in a petroleum prospective area. Using multi-client 2D and 3D seismic data we place reservoir scale observations of sill morphology, size, distribution and sill-fault interactions within a wider basin context. We have identified three distinct sill facies through detailed 3D seismic interpretation and seismic attribute analysis, each show significant morphological variations and are emplaced within contrasting structural settings. Given the variations in sill size and frequency within each facies there are also implications for bulk regional intrusive magma distribution across the margin. We demonstrate that the style and volume of sill intrusion is heavily influenced by the large scale basin structure, the position along the volcanic margin and small scale structural heterogeneities. Panel_15445 Panel_15445 8:30 AM 5:00 PM

Offshore Uruguay is considered to be an under-explored, potentially prospective region. BG Group has acquired an extensive state-of-the-art 3D seismic survey, which is being studied within the context of an existing multi-client, 2D dataset. The combination of several surveys of both high resolution and long recording times allows the influence of basement structures and volcanics to be determined, within the context of margin evolution. In this study we use 3D imaging of the Rio de la Plata transform zone to enhance our understanding of the interaction between transform faulting and the volcanic processes associated with early margin formation. In particular, we investigate the links between faulting and the spatial development of Seaward Dipping Reflectors (SDRs) within a three-dimensional perspective and use gravity and magnetic data to aid our understanding of the morphology of volcanic features along the margin. Evidence of an incipient spreading centre and raised Moho suggest there has been multiple stages of extension resulting in a complex interplay of strain and volcanism along the transform zone. We provide a number of alternatives to explain the observed features including magmatic contributions from depth in a ‘leaky’ transform system, triggered by oblique south Atlantic opening and the possible existence of an early triple junction. Although the project is primarily focused upon the Uruguayan segment, integration of the conjugate margin of Namibia/South Africa provides a unique insight into the fundamental processes associated with lithospheric extension on both sides of the margin. Offshore Uruguay is considered to be an under-explored, potentially prospective region. BG Group has acquired an extensive state-of-the-art 3D seismic survey, which is being studied within the context of an existing multi-client, 2D dataset. The combination of several surveys of both high resolution and long recording times allows the influence of basement structures and volcanics to be determined, within the context of margin evolution. In this study we use 3D imaging of the Rio de la Plata transform zone to enhance our understanding of the interaction between transform faulting and the volcanic processes associated with early margin formation. In particular, we investigate the links between faulting and the spatial development of Seaward Dipping Reflectors (SDRs) within a three-dimensional perspective and use gravity and magnetic data to aid our understanding of the morphology of volcanic features along the margin. Evidence of an incipient spreading centre and raised Moho suggest there has been multiple stages of extension resulting in a complex interplay of strain and volcanism along the transform zone. We provide a number of alternatives to explain the observed features including magmatic contributions from depth in a ‘leaky’ transform system, triggered by oblique south Atlantic opening and the possible existence of an early triple junction. Although the project is primarily focused upon the Uruguayan segment, integration of the conjugate margin of Namibia/South Africa provides a unique insight into the fundamental processes associated with lithospheric extension on both sides of the margin. Panel_15454 Panel_15454 8:30 AM 5:00 PM

In preparation for upcoming assessments of the undiscovered, technically recoverable oil and gas resources in several formations of the onshore coastal plain and State waters of the U.S. Gulf Coast, the U.S. Geological Survey (USGS) is continuing research on the generation, migration, and accumulation of hydrocarbons across the Gulf of Mexico Basin. This effort includes an examination of the impact of the basin’s structural evolution on the Upper Jurassic-Cretaceous-Tertiary Composite Total Petroleum System. The USGS has licensed and interpreted a series of regional-scale dip-oriented 2D seismic lines that cover Texas, Louisiana, and western Mississippi. The lengths of each line range from approximately 160 km to 450 km. Each seismic line begins near the coastline and extends updip across the Lower Cretaceous shelf edge. Interpretations are shown for twelve of these regional seismic lines. Analyzing this sequence of interpreted seismic lines provides a clear perspective on how key structural elements of the northwestern Gulf of Mexico Basin (including fault zones, uplifts, interior salt basins, and coastal diapir provinces) vary along strike. Based upon interpretations of these lines, structural restorations have been constructed that model the post-Middle Triassic sequential structural evolution for this part of the Gulf of Mexico Basin. Additionally, a suite of geohistory curves have been constructed for wells along each of the seismic lines in order to model the timing of hydrocarbon generation from the Oxfordian Smackover Formation and the Cenomanian-Turonian Eagle Ford Shale. Combining the seismic interpretations and structural models with the geohistory curves highlight the differences in timing of hydrocarbon generation between different Gulf Coast structural provinces. In preparation for upcoming assessments of the undiscovered, technically recoverable oil and gas resources in several formations of the onshore coastal plain and State waters of the U.S. Gulf Coast, the U.S. Geological Survey (USGS) is continuing research on the generation, migration, and accumulation of hydrocarbons across the Gulf of Mexico Basin. This effort includes an examination of the impact of the basin’s structural evolution on the Upper Jurassic-Cretaceous-Tertiary Composite Total Petroleum System. The USGS has licensed and interpreted a series of regional-scale dip-oriented 2D seismic lines that cover Texas, Louisiana, and western Mississippi. The lengths of each line range from approximately 160 km to 450 km. Each seismic line begins near the coastline and extends updip across the Lower Cretaceous shelf edge. Interpretations are shown for twelve of these regional seismic lines. Analyzing this sequence of interpreted seismic lines provides a clear perspective on how key structural elements of the northwestern Gulf of Mexico Basin (including fault zones, uplifts, interior salt basins, and coastal diapir provinces) vary along strike. Based upon interpretations of these lines, structural restorations have been constructed that model the post-Middle Triassic sequential structural evolution for this part of the Gulf of Mexico Basin. Additionally, a suite of geohistory curves have been constructed for wells along each of the seismic lines in order to model the timing of hydrocarbon generation from the Oxfordian Smackover Formation and the Cenomanian-Turonian Eagle Ford Shale. Combining the seismic interpretations and structural models with the geohistory curves highlight the differences in timing of hydrocarbon generation between different Gulf Coast structural provinces. Panel_15447 Panel_15447 8:30 AM 5:00 PM

We have carried out a reappraisal of the structural and tectonic evolution of the Mozambique Basin in the wider context of the East African Margin. Detailed interpretation of gravity and magnetic data alongside SRTM, bathymetry and Landsat data enables us to apply the most recent research in passive and transform margin formation to the East African margin. Based on these concepts, we interpret features such as exhumation of the sub-continental lithospheric mantle within broad zones of complex transitional crust, which have generally been previously unrecognised in this region. Southern Mozambique comprises the Mozambique Coastal Plains (MCP), a flat lying area bordered to the west by the Lebombo Monocline and to the north by the Matake-Sabi/Mwenetzi Monocline. The area to the east and south of these major crustal structures has been variably interpreted as continental or oceanic crust within the literature. Interpreting the MCP as continental crust causes problems in rigid plate models; overlap between two regions of known cratonic crust (Kaapvaal and Grunehogna Cratons) implies extension of cratonic crust that is unobserved. The interpretation of a fully continental basement also ignores the continuation of gravity and magnetic anomalies over the Mozambique Ridge, which we interpret as thickened oceanic crust, northwards beneath the Mozambique Coastal Plains. An entirely oceanic basement for the MCP would eradicate problematic overlaps between eastern and western Gondwana. However this is at odds with relatively thick crust (~30 km) shown underlying the area from our geophysical analyses and seismological investigations (Copley et al., 2012). Using potential field data, we define three spreading ridges in the Mozambique Ridge in agreement with Leinweber & Jokat (2012) and show the eastern part of the MCP to be underlain by thickened oceanic crust continuous with the Mozambique Ridge. This is in agreement with the drilled interception of Jurassic volcanics over the eastern part of the MCP, which were previously interpreted as Karoo-age. In the west, the interpretation of early Jurassic (pre-seafloor spreading) grabens (e.g., Salman & Abdulla, 1995) indicates the presence of continental crust; consequently, we interpret the western part of the MCP to be underlain by attenuated continental crust related to the end-Karoo (~182 Ma) formation of the Lebombo and Matake-Sabi Monoclines. We have carried out a reappraisal of the structural and tectonic evolution of the Mozambique Basin in the wider context of the East African Margin. Detailed interpretation of gravity and magnetic data alongside SRTM, bathymetry and Landsat data enables us to apply the most recent research in passive and transform margin formation to the East African margin. Based on these concepts, we interpret features such as exhumation of the sub-continental lithospheric mantle within broad zones of complex transitional crust, which have generally been previously unrecognised in this region. Southern Mozambique comprises the Mozambique Coastal Plains (MCP), a flat lying area bordered to the west by the Lebombo Monocline and to the north by the Matake-Sabi/Mwenetzi Monocline. The area to the east and south of these major crustal structures has been variably interpreted as continental or oceanic crust within the literature. Interpreting the MCP as continental crust causes problems in rigid plate models; overlap between two regions of known cratonic crust (Kaapvaal and Grunehogna Cratons) implies extension of cratonic crust that is unobserved. The interpretation of a fully continental basement also ignores the continuation of gravity and magnetic anomalies over the Mozambique Ridge, which we interpret as thickened oceanic crust, northwards beneath the Mozambique Coastal Plains. An entirely oceanic basement for the MCP would eradicate problematic overlaps between eastern and western Gondwana. However this is at odds with relatively thick crust (~30 km) shown underlying the area from our geophysical analyses and seismological investigations (Copley et al., 2012). Using potential field data, we define three spreading ridges in the Mozambique Ridge in agreement with Leinweber & Jokat (2012) and show the eastern part of the MCP to be underlain by thickened oceanic crust continuous with the Mozambique Ridge. This is in agreement with the drilled interception of Jurassic volcanics over the eastern part of the MCP, which were previously interpreted as Karoo-age. In the west, the interpretation of early Jurassic (pre-seafloor spreading) grabens (e.g., Salman & Abdulla, 1995) indicates the presence of continental crust; consequently, we interpret the western part of the MCP to be underlain by attenuated continental crust related to the end-Karoo (~182 Ma) formation of the Lebombo and Matake-Sabi Monoclines. Panel_15448 Panel_15448 8:30 AM 5:00 PM

Of the numerous models explaining the opening of the Amerasian Basin, those showing northern Alaska and the East Russian Arctic Shelf rotating away from the Canadian Arctic around an Euler pole near the MacKenzie Delta have gained the widest acceptance. However, the rotational models leave a number of unresolved issues including: 1) were the New Siberian Islands originally part of a plate encompassing Alaska-Chukotka or were these two areas juxtaposed during the opening of the Amerasian Basin across a transform requiring hundreds to thousands of kilometers of right-lateral slip, and 2) how does the Chukchi Borderland fit into a reconstruction of the plates surrounding the Amerasian Basin? The new Eastern Russian ArcticSPANTM (ERAS), a survey consisting of >13000 km of seismic covering the Laptev, East Siberian and Chukchi seas, provides a wealth of new information addressing these issues. In our opinion, the data do not show a transform that would have separated the New Siberian Islands from the Chukotka-Alaska plate, but indicate continuity of geologic trends such as the Mesozoic thrust front from Wrangel Island west to the New Siberian Islands. The survey also shows the North Chukchi-Vilkitski Basin to be filled by some 20 km of Mesozoic and Tertiary sediments and floored by oceanic crust or exhumed mantle. The west side of the basin connects with the East Siberian Sea Rift, a feature that shallows and narrows to the south. Closing this rift around an Euler pole located at the South Anyui Suture both significantly shortens the east-west extent of the greater Alaska-Chukotka-New Siberia plate and allows the Chukchi Borderland to restore into the eastern end of the North Chukchi-Vilkitski Basin. When these observations are combined with (1) a moderately tight fit for Europe and the Lomonosov Ridge relative to North America, (2) restoration of the Eurekan orogeny of the western Canadian Arctic, and (3) a postulated orocline located just west of Prudhoe Bay on Alaska’s North Slope, the circum-Arctic plates fit together with very few gaps. This plate reconstruction also brings paleomagnetic poles available for the Alaska-Chukotka-New Siberia plate into better alignment with the North American apparent polar wandering path, and presents several possible kinematic models that have implications for tectonic elements flooring the Amerasian Basin. Of the numerous models explaining the opening of the Amerasian Basin, those showing northern Alaska and the East Russian Arctic Shelf rotating away from the Canadian Arctic around an Euler pole near the MacKenzie Delta have gained the widest acceptance. However, the rotational models leave a number of unresolved issues including: 1) were the New Siberian Islands originally part of a plate encompassing Alaska-Chukotka or were these two areas juxtaposed during the opening of the Amerasian Basin across a transform requiring hundreds to thousands of kilometers of right-lateral slip, and 2) how does the Chukchi Borderland fit into a reconstruction of the plates surrounding the Amerasian Basin? The new Eastern Russian ArcticSPANTM (ERAS), a survey consisting of >13000 km of seismic covering the Laptev, East Siberian and Chukchi seas, provides a wealth of new information addressing these issues. In our opinion, the data do not show a transform that would have separated the New Siberian Islands from the Chukotka-Alaska plate, but indicate continuity of geologic trends such as the Mesozoic thrust front from Wrangel Island west to the New Siberian Islands. The survey also shows the North Chukchi-Vilkitski Basin to be filled by some 20 km of Mesozoic and Tertiary sediments and floored by oceanic crust or exhumed mantle. The west side of the basin connects with the East Siberian Sea Rift, a feature that shallows and narrows to the south. Closing this rift around an Euler pole located at the South Anyui Suture both significantly shortens the east-west extent of the greater Alaska-Chukotka-New Siberia plate and allows the Chukchi Borderland to restore into the eastern end of the North Chukchi-Vilkitski Basin. When these observations are combined with (1) a moderately tight fit for Europe and the Lomonosov Ridge relative to North America, (2) restoration of the Eurekan orogeny of the western Canadian Arctic, and (3) a postulated orocline located just west of Prudhoe Bay on Alaska’s North Slope, the circum-Arctic plates fit together with very few gaps. This plate reconstruction also brings paleomagnetic poles available for the Alaska-Chukotka-New Siberia plate into better alignment with the North American apparent polar wandering path, and presents several possible kinematic models that have implications for tectonic elements flooring the Amerasian Basin. Panel_15451 Panel_15451 8:30 AM 5:00 PM

There are four main types of plate kinematic models that have been postulated to explain the opening of the Gulf of Mexico: a) rotational-translational movement, with a pole of rotation south of Florida (e.g. Pindell and Kennan, 2009), b) rotational-translational movement, with a pole of rotation southwest of Mexico (e.g. Hall et al., 1982), c) the Gulf of Mexico has opened contemporaneously and as part of the Central atlantic (e.g. Klitgord and Schouten, 1986), d) models that suggest more complex relations with Caribbean subduction and ocean spreading (e.g. Dutch, 2009). Each of these models requires differing driving forces and modes of opening for the Gulf of Mexico and lead to different types of margin formation across the different segments of the Gulf of Mexico. These differences affect the history, geometry and volume of accommodation space for source rocks, seals and reservoirs, with concomitant impacts on ocean circulation, source to sink relations and depositional systems. Additionally, subsequent deformation phases, such as the Laramide Orogeny across Mexico can be also be represented in the plate model’s global context. Such events have a great influence on fault reactivation and, consequently, on fluid migration and trap formation. In this paper we present a refined tectonic plate model that details the tectonic evolution of the Gulf of Mexico and highlights the impact of different, existing models on the development of petroleum systems. Our model is based on the interpretation of remote sensing (Gravity and Magnetic, Landsat, SRTM) and public domain data, that were used to create a 1:1 000 000 scale structural coverage and detailed understanding of the crustal types and crustal architecture. This forms the foundations for a regional plate model which is constrained further by placing it into the context of a global plate model to understand the consequences and interactions it may have within the greater global plate circuit. There are four main types of plate kinematic models that have been postulated to explain the opening of the Gulf of Mexico: a) rotational-translational movement, with a pole of rotation south of Florida (e.g. Pindell and Kennan, 2009), b) rotational-translational movement, with a pole of rotation southwest of Mexico (e.g. Hall et al., 1982), c) the Gulf of Mexico has opened contemporaneously and as part of the Central atlantic (e.g. Klitgord and Schouten, 1986), d) models that suggest more complex relations with Caribbean subduction and ocean spreading (e.g. Dutch, 2009). Each of these models requires differing driving forces and modes of opening for the Gulf of Mexico and lead to different types of margin formation across the different segments of the Gulf of Mexico. These differences affect the history, geometry and volume of accommodation space for source rocks, seals and reservoirs, with concomitant impacts on ocean circulation, source to sink relations and depositional systems. Additionally, subsequent deformation phases, such as the Laramide Orogeny across Mexico can be also be represented in the plate model’s global context. Such events have a great influence on fault reactivation and, consequently, on fluid migration and trap formation. In this paper we present a refined tectonic plate model that details the tectonic evolution of the Gulf of Mexico and highlights the impact of different, existing models on the development of petroleum systems. Our model is based on the interpretation of remote sensing (Gravity and Magnetic, Landsat, SRTM) and public domain data, that were used to create a 1:1 000 000 scale structural coverage and detailed understanding of the crustal types and crustal architecture. This forms the foundations for a regional plate model which is constrained further by placing it into the context of a global plate model to understand the consequences and interactions it may have within the greater global plate circuit. Panel_15449 Panel_15449 8:30 AM 5:00 PM

Compositional and structural variations within crystalline basement may influence the nucleation and growth of normal faults and hence, the overall rift geometry. However, the degree to which basement heterogeneities control normal fault evolution has not been studied in detail yet and remains a fundamental research theme given that large volumes of hydrocarbons remain in rifts that have evolved above heterogeneous basement. Furthermore, limitations in the depth of conventional seismic imaging, the commonly acoustically transparent nature of basement, minimal well penetrations, and complex overprinting of multiple tectonic events often complicate investigations of the crust beneath sedimentary basins. This study integrates 3D seismic reflection, borehole, and potential field data to identify variations in basement composition and to examine their influence on normal fault growth and rift structural style, offshore Mid-Norway; covering an area of approximately 3000 km2. Intra-basement structures are well-imaged on seismic and potential field data in this area due to relatively shallow burial of the basement beneath a rather thin sedimentary cover (<3.5 km). We aim to determine the offshore continuation of Precambrian basement, Caledonian nappes and Devonian basins which are well documented on the Norwegian mainland performing extensive 3D mapping of intra-basement reflections and seismic facies. Additionally, 2D gravity and magnetic data modelling provide further constraints on the upper and lower crustal configuration. Variations in basement composition along the Mid-Norwegian margin have been interpreted involving Western Gneiss cored anticlines and the presence of basement folds and mylonite zones. Preliminary results from quantitative fault analysis indicate a distinct change in fault characteristics and strain distribution on faults from S to N. This change in fault properties can be correlated with the suspected variations in basement composition and structure. Therefore, we propose that the observed changes in structural style and fault characteristics may be influenced by variations in basement composition and pre-existing weaknesses. The results of this study not only provide a fundamental understanding of normal fault growth above heterogeneous basement but also show the potential of integrating different geophysical datasets for determining the structural and compositional nature of crystalline basement in the absence of sufficient borehole control. Compositional and structural variations within crystalline basement may influence the nucleation and growth of normal faults and hence, the overall rift geometry. However, the degree to which basement heterogeneities control normal fault evolution has not been studied in detail yet and remains a fundamental research theme given that large volumes of hydrocarbons remain in rifts that have evolved above heterogeneous basement. Furthermore, limitations in the depth of conventional seismic imaging, the commonly acoustically transparent nature of basement, minimal well penetrations, and complex overprinting of multiple tectonic events often complicate investigations of the crust beneath sedimentary basins. This study integrates 3D seismic reflection, borehole, and potential field data to identify variations in basement composition and to examine their influence on normal fault growth and rift structural style, offshore Mid-Norway; covering an area of approximately 3000 km². Intra-basement structures are well-imaged on seismic and potential field data in this area due to relatively shallow burial of the basement beneath a rather thin sedimentary cover (<3.5 km). We aim to determine the offshore continuation of Precambrian basement, Caledonian nappes and Devonian basins which are well documented on the Norwegian mainland performing extensive 3D mapping of intra-basement reflections and seismic facies. Additionally, 2D gravity and magnetic data modelling provide further constraints on the upper and lower crustal configuration. Variations in basement composition along the Mid-Norwegian margin have been interpreted involving Western Gneiss cored anticlines and the presence of basement folds and mylonite zones. Preliminary results from quantitative fault analysis indicate a distinct change in fault characteristics and strain distribution on faults from S to N. This change in fault properties can be correlated with the suspected variations in basement composition and structure. Therefore, we propose that the observed changes in structural style and fault characteristics may be influenced by variations in basement composition and pre-existing weaknesses. The results of this study not only provide a fundamental understanding of normal fault growth above heterogeneous basement but also show the potential of integrating different geophysical datasets for determining the structural and compositional nature of crystalline basement in the absence of sufficient borehole control. Panel_15456 Panel_15456 8:30 AM 5:00 PM

Our team has analysed a set of more than 1500 crude oil samples for African and South American basins, placed them in their tectono-structural setting and tested the resulting maps by comparing paleo-reconstructions of the region against the paleo-depositional settings inferred from the oils data. This poster has for its focus the southern South Atlantic conjugate basins. Of particular interest are plays related to Upper Jurassic-Neocomian syn-rift lacustrine source rocks. Our tectono-structural interpretation uses recent compilations of geophysical data (bathymetry, gravity, magnetics, basement depth, sediment thickness) to direct and refine our mapping of the regional tectonic elements and basin features. We illustrate South Atlantic conjugate regions, namely the continental terraces from Southern Brazil across Argentina and from Namibia across South Africa. The northern segment, influenced by a Proterozoic craton, contains relatively shallow margin basins extending from Pelotas to the Salado-Colorado Mesozoic aulacogens and their counterparts the Namibia-Luderitz-Orange basins. The southern segment, Patagonia, extends from the Colorado Anomaly to the Malvinas (Falkland) Plateau where our magnetics displays help image the influence of Triassic and Jurassic volcanism (LIPS). The geochemical point control has iterated through an expanding data volume (Schiefelbein & Dickson 2014) using a combination of multivariate statistical analysis (MSA) and spatial comparisons to tecto-structural mapping. Our poster illustrates examples of MSA significance, matching rift basin and sub-basin containers with inferred paleo-geographies and associated ages derived from the oils analysis. Our team has analysed a set of more than 1500 crude oil samples for African and South American basins, placed them in their tectono-structural setting and tested the resulting maps by comparing paleo-reconstructions of the region against the paleo-depositional settings inferred from the oils data. This poster has for its focus the southern South Atlantic conjugate basins. Of particular interest are plays related to Upper Jurassic-Neocomian syn-rift lacustrine source rocks. Our tectono-structural interpretation uses recent compilations of geophysical data (bathymetry, gravity, magnetics, basement depth, sediment thickness) to direct and refine our mapping of the regional tectonic elements and basin features. We illustrate South Atlantic conjugate regions, namely the continental terraces from Southern Brazil across Argentina and from Namibia across South Africa. The northern segment, influenced by a Proterozoic craton, contains relatively shallow margin basins extending from Pelotas to the Salado-Colorado Mesozoic aulacogens and their counterparts the Namibia-Luderitz-Orange basins. The southern segment, Patagonia, extends from the Colorado Anomaly to the Malvinas (Falkland) Plateau where our magnetics displays help image the influence of Triassic and Jurassic volcanism (LIPS). The geochemical point control has iterated through an expanding data volume (Schiefelbein & Dickson 2014) using a combination of multivariate statistical analysis (MSA) and spatial comparisons to tecto-structural mapping. Our poster illustrates examples of MSA significance, matching rift basin and sub-basin containers with inferred paleo-geographies and associated ages derived from the oils analysis. Panel_15453 Panel_15453 8:30 AM 5:00 PM

The evolution of sedimentary systems within rift basins is primarily controlled by the feedback interaction of surface processes and tectonics. Deformation along a margin provides material for erosion/transport and accommodation space for deposition; while changes in climate influence the supply and transport of source materials, and subsequently the total isostatic and thermal impact of sediment from source to sink. Despite the recognition of this link, decoding the sedimentary signals recorded in basins of the relative impact of surface vs. tectonic forcing remains a significant challenge. This problem is due, in part, because analogue and 2D numerical models are unable to simulate the non-linear thermo-mechanical feedback loops between high-detail surface processes (sediment yield, dispersion, stratigraphy) and the large-scale (spatially and temporally) tectonics of continental rifting. To overcome this limitation, we have coupled a set of self-consistent numerical frameworks capable of simulating the landscape evolution on a thermally and mechanically realistic lithosphere under tectonic forcing. With this coupled framework, we can investigate the evolution of basins down to the grain-scale, while incorporating the influences of isostatic, tectonic, and deep Earth forces. To demonstrate this new toolkit, we have run a number of experiments on rifting continental lithosphere under different climatic forcing. By varying the mode of surface processes (none, elevation thresholds, self-consistent coupling), we find that only the coupled model is able to produce the range of natural complexities seen in nature, including migration of depocentres, transition of sinks to sources, thermal blanketing, and dynamic links between surface loading/unloading and faulting. This work is part of the Basin GENESIS Hub, a new 5-year project based on a consortium of Australian Universities and industry partners. By combining existing and new workflows for climate, stratigraphic, tectonic, and mantle convection modelling into a cohesive workbench, we hope to develop new knowledge incorporating deep to surface processes involved in the formation and evolution of basins. This also opens opportunities for data assimilation methods and uncertainty quantification, leading to a new generation of 5D basin models (space, time, uncertainty). The evolution of sedimentary systems within rift basins is primarily controlled by the feedback interaction of surface processes and tectonics. Deformation along a margin provides material for erosion/transport and accommodation space for deposition; while changes in climate influence the supply and transport of source materials, and subsequently the total isostatic and thermal impact of sediment from source to sink. Despite the recognition of this link, decoding the sedimentary signals recorded in basins of the relative impact of surface vs. tectonic forcing remains a significant challenge. This problem is due, in part, because analogue and 2D numerical models are unable to simulate the non-linear thermo-mechanical feedback loops between high-detail surface processes (sediment yield, dispersion, stratigraphy) and the large-scale (spatially and temporally) tectonics of continental rifting. To overcome this limitation, we have coupled a set of self-consistent numerical frameworks capable of simulating the landscape evolution on a thermally and mechanically realistic lithosphere under tectonic forcing. With this coupled framework, we can investigate the evolution of basins down to the grain-scale, while incorporating the influences of isostatic, tectonic, and deep Earth forces. To demonstrate this new toolkit, we have run a number of experiments on rifting continental lithosphere under different climatic forcing. By varying the mode of surface processes (none, elevation thresholds, self-consistent coupling), we find that only the coupled model is able to produce the range of natural complexities seen in nature, including migration of depocentres, transition of sinks to sources, thermal blanketing, and dynamic links between surface loading/unloading and faulting. This work is part of the Basin GENESIS Hub, a new 5-year project based on a consortium of Australian Universities and industry partners. By combining existing and new workflows for climate, stratigraphic, tectonic, and mantle convection modelling into a cohesive workbench, we hope to develop new knowledge incorporating deep to surface processes involved in the formation and evolution of basins. This also opens opportunities for data assimilation methods and uncertainty quantification, leading to a new generation of 5D basin models (space, time, uncertainty). Panel_15455 Panel_15455 8:30 AM 5:00 PM

In this presentation we show our new modeling software, Kynedin, that can be used to simulate basement topography, heat-flow, subsidence and sedimentation patterns during rift and post-rift phases along a given seismic profile. This program gives as output the distribution in time and space of faulting, crustal and lithospheric thinning, heat flow, subsidence and sedimentation, effectively combining results that are traditionally obtained with a combination of section restoration and forward modeling techniques. The model combines a kinematic treatment of sedimentation and upper crustal faulting with a dynamic description of lower crust and mantle deformation. The latter deform as non-Newtonian fluids with a viscosity that depends on strain rate and temperature. The code reproduces whole lithospheric deformation more realistically than traditional forward models based on kinematic approaches, where all lithospheric deformation is prescribed with geometric rules. This is because the feedbacks that occur during rifting between upper crustal faulting and ductile lithosphere deformation depart from the traditional pure-shear (either uniform or non-uniform) kinematic descriptions typically implemented in forward models of lithospheric deformation during extension. Our program includes a user interface where interpreted faults on a given seismic profile can be digitized and given as input for the model. Likewise, crustal and lithospheric thickness, the initial temperature field, and lower crustal rheology and extension velocities are given as inputs to the model. In this presentation we use a seismic line along the magma poor West Iberia margin to demonstrate how the code works and its abilities. In this presentation we show our new modeling software, Kynedin, that can be used to simulate basement topography, heat-flow, subsidence and sedimentation patterns during rift and post-rift phases along a given seismic profile. This program gives as output the distribution in time and space of faulting, crustal and lithospheric thinning, heat flow, subsidence and sedimentation, effectively combining results that are traditionally obtained with a combination of section restoration and forward modeling techniques. The model combines a kinematic treatment of sedimentation and upper crustal faulting with a dynamic description of lower crust and mantle deformation. The latter deform as non-Newtonian fluids with a viscosity that depends on strain rate and temperature. The code reproduces whole lithospheric deformation more realistically than traditional forward models based on kinematic approaches, where all lithospheric deformation is prescribed with geometric rules. This is because the feedbacks that occur during rifting between upper crustal faulting and ductile lithosphere deformation depart from the traditional pure-shear (either uniform or non-uniform) kinematic descriptions typically implemented in forward models of lithospheric deformation during extension. Our program includes a user interface where interpreted faults on a given seismic profile can be digitized and given as input for the model. Likewise, crustal and lithospheric thickness, the initial temperature field, and lower crustal rheology and extension velocities are given as inputs to the model. In this presentation we use a seismic line along the magma poor West Iberia margin to demonstrate how the code works and its abilities. Panel_15446 Panel_15446 8:30 AM 5:00 PM

The Ceduna Sub-basin is the main depocentre of the frontier Bight Basin, which formed as a result of the late Jurassic-Cenozoic separation of Australia and Antarctica. The sedimentary fill of the Ceduna Sub-basin is dominated by two structurally distinct deltaic lobes of Cenomanian and Santonian-Maastrichtian age with a combined thickness exceeding 12 km. These lobes are collectively known as the Ceduna Delta, which is likely the largest deltaic system to have existed in the geological history of the Australian continent. Understanding the origin and evolution the Ceduna Sub-basin is of profound importance for Mesozoic palaeogeographic reconstructions of Australia. Furthermore, this region is the focus of growing exploration interest, and thus improved knowledge of its origin and evolution is essential for reducing exploration uncertainty. However, because the Ceduna sub-basin is located completely offshore in water depths up to 5 km, to date there has been little exploratory drilling in this region, with only one well drilled in water depths >300 m. With primary data from the sub-basin itself lacking, we have collected a variety of new thermochronological (e.g. apatite fission track analysis (AFTA) and vitrinite reflectance (VR)) and geochronological (e.g. zircon U-Pb and fission track) datasets from the onshore margins and hinterland, which have a bearing on the evolution of the offshore region. These datasets include: (1) Zircon U-Pb ages from several samples of drillcore from the Lower Cretaceous Loongana Formation, which underlies the onshore Eucla Basin. Age populations within these data suggest that sediment input at this time was predominantly from the north and west. (2) AFTA and VR data from outcropping and subsurface rocks in the Eyre Peninsula, to the northeast of the Ceduna sub-basin. These data point to substantial exhumation of this region during the late Cretaceous. (3) Zircon U-Pb and fission track ages from the Turonian-Maastrichtian sequence penetrated by the offshore Gnarlyknots-1 well. These ages suggest that this sequence was largely sourced from recycled Permian-Early Cretaceous cover and underlying basement rocks eroded from the proximal, northeastern basin margin. The integration of these onshore and offshore datasets provides new, valuable insights into the Cretaceous palaeogeography of the Ceduna sub-basin, the tectonic processes controlling the input of clastic sediments, and the prospectivity of this frontier region. The Ceduna Sub-basin is the main depocentre of the frontier Bight Basin, which formed as a result of the late Jurassic-Cenozoic separation of Australia and Antarctica. The sedimentary fill of the Ceduna Sub-basin is dominated by two structurally distinct deltaic lobes of Cenomanian and Santonian-Maastrichtian age with a combined thickness exceeding 12 km. These lobes are collectively known as the Ceduna Delta, which is likely the largest deltaic system to have existed in the geological history of the Australian continent. Understanding the origin and evolution the Ceduna Sub-basin is of profound importance for Mesozoic palaeogeographic reconstructions of Australia. Furthermore, this region is the focus of growing exploration interest, and thus improved knowledge of its origin and evolution is essential for reducing exploration uncertainty. However, because the Ceduna sub-basin is located completely offshore in water depths up to 5 km, to date there has been little exploratory drilling in this region, with only one well drilled in water depths >300 m. With primary data from the sub-basin itself lacking, we have collected a variety of new thermochronological (e.g. apatite fission track analysis (AFTA) and vitrinite reflectance (VR)) and geochronological (e.g. zircon U-Pb and fission track) datasets from the onshore margins and hinterland, which have a bearing on the evolution of the offshore region. These datasets include: (1) Zircon U-Pb ages from several samples of drillcore from the Lower Cretaceous Loongana Formation, which underlies the onshore Eucla Basin. Age populations within these data suggest that sediment input at this time was predominantly from the north and west. (2) AFTA and VR data from outcropping and subsurface rocks in the Eyre Peninsula, to the northeast of the Ceduna sub-basin. These data point to substantial exhumation of this region during the late Cretaceous. (3) Zircon U-Pb and fission track ages from the Turonian-Maastrichtian sequence penetrated by the offshore Gnarlyknots-1 well. These ages suggest that this sequence was largely sourced from recycled Permian-Early Cretaceous cover and underlying basement rocks eroded from the proximal, northeastern basin margin. The integration of these onshore and offshore datasets provides new, valuable insights into the Cretaceous palaeogeography of the Ceduna sub-basin, the tectonic processes controlling the input of clastic sediments, and the prospectivity of this frontier region. Panel_15457 Panel_15457 8:30 AM 5:00 PM

The pre-Cenozoic tectonic history of the Gulf of Mexico (GoM) can be broadly described as Triassic rifting, followed by Jurassic seafloor spreading, and post-rift igneous activity as well as rapid subsidence during the Late Cretaceous. The igneous system, emplaced ca. 108 – 65 Ma, mainly consists of alkaline basalts, as well as nepheline syenites, carbonatites and phonolites, of which some are characteristically derived from the sublithospheric mantle. They span the entirety of the Northern GoM from the Uvalde and Balcones volcanic fields in Texas, through Louisiana and Arkansas, to the Jackson Dome in Mississippi. How this widespread magmatism affected the structural framework and thermal history of the basement and the overlying sedimentary package is still not clear. Competing hypotheses regarding the post-rift magmatism in the Gulf of Mexico include: 1) Magmatism in the Northern GoM was a consequence of the Bermuda hotspot as the North America plate moved over it; 2) Extensional reactivation of Ouachita-Appalachian and Grenville structures led to low-degree melting, due to crustal flexure induced by increased sediment load and/or compression in the western US; 3) Edge-driven mantle convection produced melts at the continent-ocean boundary; and 4) Tearing of stagnant Farallon slabs caused asthenospheric upwelling, decompression melting, and magma emplacement. Preliminary results show that there is no eastward age progression as predicted by the Bermuda hotspot hypothesis. Our S-wave tomography in Texas area reveals an overlap of the Uvalde-Balcones Igneous Province with the boundary between S-wave velocity anomalies in the crust and upper mantle, as well as the remnant of the Ouachita suture. While the spacing among igneous provinces matches the predicted size of edge-driven convection cells, this model does not readily explain the timing of the magmatism. It is also possible that tearing of a Farallon slab could trigger magmatism ca. 1200 km from the trench along the western margin of North America; a modern analog is the Changbai volcano associated with the stagnant Pacific slab in northeast Asia. We are acquiring new igneous rock ages and geochemical data, and integrating seismic reflection, tomography, and potential field data. This study aims to unravel the Late Cretaceous lithospheric structure and thermal evolution of the northern GoM, and to better understand the influence of post-rift magmatism on petroleum systems at passive margins. The pre-Cenozoic tectonic history of the Gulf of Mexico (GoM) can be broadly described as Triassic rifting, followed by Jurassic seafloor spreading, and post-rift igneous activity as well as rapid subsidence during the Late Cretaceous. The igneous system, emplaced ca. 108 – 65 Ma, mainly consists of alkaline basalts, as well as nepheline syenites, carbonatites and phonolites, of which some are characteristically derived from the sublithospheric mantle. They span the entirety of the Northern GoM from the Uvalde and Balcones volcanic fields in Texas, through Louisiana and Arkansas, to the Jackson Dome in Mississippi. How this widespread magmatism affected the structural framework and thermal history of the basement and the overlying sedimentary package is still not clear. Competing hypotheses regarding the post-rift magmatism in the Gulf of Mexico include: 1) Magmatism in the Northern GoM was a consequence of the Bermuda hotspot as the North America plate moved over it; 2) Extensional reactivation of Ouachita-Appalachian and Grenville structures led to low-degree melting, due to crustal flexure induced by increased sediment load and/or compression in the western US; 3) Edge-driven mantle convection produced melts at the continent-ocean boundary; and 4) Tearing of stagnant Farallon slabs caused asthenospheric upwelling, decompression melting, and magma emplacement. Preliminary results show that there is no eastward age progression as predicted by the Bermuda hotspot hypothesis. Our S-wave tomography in Texas area reveals an overlap of the Uvalde-Balcones Igneous Province with the boundary between S-wave velocity anomalies in the crust and upper mantle, as well as the remnant of the Ouachita suture. While the spacing among igneous provinces matches the predicted size of edge-driven convection cells, this model does not readily explain the timing of the magmatism. It is also possible that tearing of a Farallon slab could trigger magmatism ca. 1200 km from the trench along the western margin of North America; a modern analog is the Changbai volcano associated with the stagnant Pacific slab in northeast Asia. We are acquiring new igneous rock ages and geochemical data, and integrating seismic reflection, tomography, and potential field data. This study aims to unravel the Late Cretaceous lithospheric structure and thermal evolution of the northern GoM, and to better understand the influence of post-rift magmatism on petroleum systems at passive margins. Panel_15452 Panel_15452 8:30 AM 5:00 PM

Gravity driven collapse systems occur on most of the world’s passive continental margins and are becoming an increasingly attractive target for hydrocarbon exploration. Existing models that assume a balanced up-dip extension coupled to a down-dip toe thrust system have recently been called into question because of a growing consensus that there is commonly a mis-balance with an excess of extensional strain. Previous studies have focussed on seismic or experimental data partially due to the lack of onshore field examples on which sub-seismic features can be observed; this has left a gap in our understanding of their temporal and spatial evolution. In this study we consider field examples of a shale detachment gravity driven systems in Northern Spain, in which we observed multiple smaller scale compressive features. These structures are contained within the extensional portion of the collapse system imply considerable internal compaction prior to the formation of a down dip compressional domain. We use these field observations to re-interpret seismic examples of multiple shale driven collapses in the Orange Basin, offshore Namibia and South Africa. These seismic examples show considerable variations in style and complexity including; multiple detachment horizons lines containing only extensional features and numerous reactivations. We undertake multiple restorations of both field and seismic examples to estimate the effect of smaller scale deformation on measurements of extension versus compression. Our results suggest that this sub-seismic scale strain can account for up to 10% of previously unrecognized compression. By applying our observations from the field to seismic examples we are able to interpret structures close to seismic resolution and make predictions about the likely effects of sub-seismic features on reservoir prospectivity, hazard prediction, permeability and porosity Gravity driven collapse systems occur on most of the world’s passive continental margins and are becoming an increasingly attractive target for hydrocarbon exploration. Existing models that assume a balanced up-dip extension coupled to a down-dip toe thrust system have recently been called into question because of a growing consensus that there is commonly a mis-balance with an excess of extensional strain. Previous studies have focussed on seismic or experimental data partially due to the lack of onshore field examples on which sub-seismic features can be observed; this has left a gap in our understanding of their temporal and spatial evolution. In this study we consider field examples of a shale detachment gravity driven systems in Northern Spain, in which we observed multiple smaller scale compressive features. These structures are contained within the extensional portion of the collapse system imply considerable internal compaction prior to the formation of a down dip compressional domain. We use these field observations to re-interpret seismic examples of multiple shale driven collapses in the Orange Basin, offshore Namibia and South Africa. These seismic examples show considerable variations in style and complexity including; multiple detachment horizons lines containing only extensional features and numerous reactivations. We undertake multiple restorations of both field and seismic examples to estimate the effect of smaller scale deformation on measurements of extension versus compression. Our results suggest that this sub-seismic scale strain can account for up to 10% of previously unrecognized compression. By applying our observations from the field to seismic examples we are able to interpret structures close to seismic resolution and make predictions about the likely effects of sub-seismic features on reservoir prospectivity, hazard prediction, permeability and porosity Panel_15450 Panel_15450 8:30 AM 5:00 PM

Panel_14484 Panel_14484 8:30 AM 5:00 PM

Shallow hazards in offshore oilfield developments often come in the form of gas chimneys and shallow gas emplacements, and can endanger the integrity of rig or platform foundations as well as ongoing drilling operations. Therefore mapping them accurately prior to any drilling or development operations can be critical for safety, and reducing costs due to interruptions. An analysis was carried out to determine if 3D seismic, interrogated in a data driven but interpreter guided fashion, could be used to build a subsurface model revealing in detail where gas escape chimneys feed shallow gas accumulations, allowing the shallow hazards to not only be mapped accurately and reduce risk, but also inform the risk of trap leakage. Modern high-resolution 3D seismic is often more than adequate to locate such features and capture their extents, it is available from the main reservoir interpretation at no extra cost, and with its large areal coverage can locate and prioritize targets for ultra-high resolution shallow hazard surveys. A dataset over the Maari field, Taranaki basin, offshore New Zealand was used for the analysis. Although the field was discovered in 1983, it was not produced until 2009, due to complexities of commercialization requiring many injection and production wells. This complexity increases the importance of a thorough subsurface understanding of hazards and their geometries. The method followed was to initially condition the data using structurally oriented, edge preserving noise attenuation filters. This increased the signal to noise ratio, and helped discriminate genuinely chaotic gas signatures from the background seismic. Attribute analyses, including frequency decomposition and RGB blending, clearly revealed the presence of three main gas chimneys, and associated shallow gas accumulations. Crucially these gas chimneys were traced to specific leakage points in the reservoir units. Finally, these results were used as the basis for geobody extractions that when combined together, comprised a subsurface model that accurately described the movement of gas from depth to accumulation points in the shallow zone. The analysis proved an effective and accurate method for quickly building a subsurface model that not only located shallow hazard risk and provided targets for special survey analysis, but also tied that information back to the reservoir itself, providing an insight into the post-trap migration of hydrocarbons and trap effectiveness. Shallow hazards in offshore oilfield developments often come in the form of gas chimneys and shallow gas emplacements, and can endanger the integrity of rig or platform foundations as well as ongoing drilling operations. Therefore mapping them accurately prior to any drilling or development operations can be critical for safety, and reducing costs due to interruptions. An analysis was carried out to determine if 3D seismic, interrogated in a data driven but interpreter guided fashion, could be used to build a subsurface model revealing in detail where gas escape chimneys feed shallow gas accumulations, allowing the shallow hazards to not only be mapped accurately and reduce risk, but also inform the risk of trap leakage. Modern high-resolution 3D seismic is often more than adequate to locate such features and capture their extents, it is available from the main reservoir interpretation at no extra cost, and with its large areal coverage can locate and prioritize targets for ultra-high resolution shallow hazard surveys. A dataset over the Maari field, Taranaki basin, offshore New Zealand was used for the analysis. Although the field was discovered in 1983, it was not produced until 2009, due to complexities of commercialization requiring many injection and production wells. This complexity increases the importance of a thorough subsurface understanding of hazards and their geometries. The method followed was to initially condition the data using structurally oriented, edge preserving noise attenuation filters. This increased the signal to noise ratio, and helped discriminate genuinely chaotic gas signatures from the background seismic. Attribute analyses, including frequency decomposition and RGB blending, clearly revealed the presence of three main gas chimneys, and associated shallow gas accumulations. Crucially these gas chimneys were traced to specific leakage points in the reservoir units. Finally, these results were used as the basis for geobody extractions that when combined together, comprised a subsurface model that accurately described the movement of gas from depth to accumulation points in the shallow zone. The analysis proved an effective and accurate method for quickly building a subsurface model that not only located shallow hazard risk and provided targets for special survey analysis, but also tied that information back to the reservoir itself, providing an insight into the post-trap migration of hydrocarbons and trap effectiveness. Panel_15492 Panel_15492 8:30 AM 5:00 PM

Basin-scale modeling of the Jurassic Navajo and Entrada Sandstone and the Late Cretaceous Dakota-Cedar Mountain Formations (undifferentiated) was conducted for two projects: (1) to calculate the CO2 storage capacity for the NATCARB database and (2) to evaluate water production from and potential disposal of water into reservoirs in the Uinta Basin. Several other reservoirs not discussed here were modeled for both projects. Mapping for the projects consisted of structure, gross and net thickness, net feet of porosity, and bubble maps of cumulative and monthly gas and water production. Water quality data were collected for the three reservoirs, which show spatial and depth variation of both quality and composition. Maps were first hand contoured in order to make reasonable projections into deeper portions of the basin where well control is lacking. Each of the contour maps was digitized, creating point data every 3000 feet along each contour line. The contour data points were added to the well data and then gridded in ArcMap. An average porosity value was assigned to each grid cell for calculation of storage. However, the average porosity resulted in an overestimation of storage capacity in the deeper portions of the basin where porosity is often significantly lower than the average. To improve the models we calculated feet of sandstone with 6% and 12% porosity using porosity logs. We then plotted the ratios of feet of 6% and 12% porosity over total feet of sandstone against depth. A ratio-depth equation was calculated for each reservoir and the models were recalculated. Areas of high CO2 storage capacity are assumed to also have high waste-water storage potential. Basin-scale modeling of the Jurassic Navajo and Entrada Sandstone and the Late Cretaceous Dakota-Cedar Mountain Formations (undifferentiated) was conducted for two projects: (1) to calculate the CO₂ storage capacity for the NATCARB database and (2) to evaluate water production from and potential disposal of water into reservoirs in the Uinta Basin. Several other reservoirs not discussed here were modeled for both projects. Mapping for the projects consisted of structure, gross and net thickness, net feet of porosity, and bubble maps of cumulative and monthly gas and water production. Water quality data were collected for the three reservoirs, which show spatial and depth variation of both quality and composition. Maps were first hand contoured in order to make reasonable projections into deeper portions of the basin where well control is lacking. Each of the contour maps was digitized, creating point data every 3000 feet along each contour line. The contour data points were added to the well data and then gridded in ArcMap. An average porosity value was assigned to each grid cell for calculation of storage. However, the average porosity resulted in an overestimation of storage capacity in the deeper portions of the basin where porosity is often significantly lower than the average. To improve the models we calculated feet of sandstone with 6% and 12% porosity using porosity logs. We then plotted the ratios of feet of 6% and 12% porosity over total feet of sandstone against depth. A ratio-depth equation was calculated for each reservoir and the models were recalculated. Areas of high CO₂ storage capacity are assumed to also have high waste-water storage potential. Panel_15491 Panel_15491 8:30 AM 5:00 PM

We are using airborne lidar and satellite-based radar interferometry (InSAR) to quantify short-term (months to years) and longer-term (decades) subsidence in the area surrounding two large (100- to 200-m diameter) sinkholes that formed above Permian bedded salt in 1980 and 2002 in the Hendrick Field near Wink, Texas. Radar interferograms constructed from synthetic aperture radar data acquired between 2008 and 2011 with the ALOS PALSAR L-band satellite-borne instrument reveal local areas that are subsiding at rates that reach a few cm per month. Subsiding areas identified on radar interferograms enable labor-intensive ground investigations (such as microgravity surveys) to focus on areas where subsidence is occurring and shallow-source mass deficits might exist that could be sites of future subsidence or collapse. Longer-term elevation changes are being quantified by comparing digital elevation models (DEMs) constructed from high-resolution airborne lidar data acquired over a 32 square km area in 2013 with older, lower-resolution DEMs constructed from data acquired during the NASA- and NGA-sponsored Shuttle Radar Topographic Mission in February 2000 and from USGS aerial photogrammetry-derived topographic data from the 1960s. Total subsidence reaches more than 10 m over 45 years in some areas. Maximum rates of subsidence measured on annual (from InSAR) and decadal (from lidar) time scales are about 0.25 m/yr. In addition to showing the extent and magnitude of subsidence at the 1980 and 2002 sinkholes, comparison of the 2013 lidar-derived DEM with the 1960s photogrammetry-derived DEM revealed other locations that have undergone significant (more than 1 m) elevation change since the 1960s, but show no evidence of recent (2008 to 2011) ground motion from satellite radar interferograms. Regional coverage obtained by radar interferometry and local coverage obtained with airborne lidar show that areas of measurable subsidence are all within a few km of the 1980 and 2002 sinkholes. We are using airborne lidar and satellite-based radar interferometry (InSAR) to quantify short-term (months to years) and longer-term (decades) subsidence in the area surrounding two large (100- to 200-m diameter) sinkholes that formed above Permian bedded salt in 1980 and 2002 in the Hendrick Field near Wink, Texas. Radar interferograms constructed from synthetic aperture radar data acquired between 2008 and 2011 with the ALOS PALSAR L-band satellite-borne instrument reveal local areas that are subsiding at rates that reach a few cm per month. Subsiding areas identified on radar interferograms enable labor-intensive ground investigations (such as microgravity surveys) to focus on areas where subsidence is occurring and shallow-source mass deficits might exist that could be sites of future subsidence or collapse. Longer-term elevation changes are being quantified by comparing digital elevation models (DEMs) constructed from high-resolution airborne lidar data acquired over a 32 square km area in 2013 with older, lower-resolution DEMs constructed from data acquired during the NASA- and NGA-sponsored Shuttle Radar Topographic Mission in February 2000 and from USGS aerial photogrammetry-derived topographic data from the 1960s. Total subsidence reaches more than 10 m over 45 years in some areas. Maximum rates of subsidence measured on annual (from InSAR) and decadal (from lidar) time scales are about 0.25 m/yr. In addition to showing the extent and magnitude of subsidence at the 1980 and 2002 sinkholes, comparison of the 2013 lidar-derived DEM with the 1960s photogrammetry-derived DEM revealed other locations that have undergone significant (more than 1 m) elevation change since the 1960s, but show no evidence of recent (2008 to 2011) ground motion from satellite radar interferograms. Regional coverage obtained by radar interferometry and local coverage obtained with airborne lidar show that areas of measurable subsidence are all within a few km of the 1980 and 2002 sinkholes. Panel_15488 Panel_15488 8:30 AM 5:00 PM

The quality of seismic image of underlying strata is negatively affected by shallow gas. Seismic events below shallow gas are dominated by several special phenomena such as low frequency, drop-down and weak energy. Therefore, it is difficult to predict the depth of target zone accurately. Thus the drilling risk of horizontal wells is greatly raised as well. Currently, the influence of shallow gas on underlying strata is still under qualitative analysis. The purpose of this paper is to quantize the gas influence in order to provide a solution to achieve accurate depth prediction of target zone. In this paper, the influence mechanism of shallow gas on underlying strata is discussed in detail. Based on the discussion we find out main influential factors, including thickness of gas-bearing layer, horizontal scale of gas-bearing layer, buried depth of gas-bearing layer, distance between gas-bearing layer and target layer, receiving cable length and the formation velocity. With certain simplifications, we write a program to calculate the influence range and extent of shallow gas on underlying strata with main influential factors. Although there are some differences between simulation and the real situation, it is available to intuitively present the influence of shallow gas. Furthermore, we build many models based on different gas-bearing formation conditions to achieve pre-stack forward modeling with formation velocities derived from real drilling data in Bohai Bay Basin. Then we complete pre-stack time migration with shot records derived from forward modeling. Finally, we build a series of time correlation templates related to different offsets and depth of underlying strata through event auto-tracking and interpolation. The templates are applied to quantitatively estimate time correlation caused by shallow gas for any point of underlying strata, thus we achieve to improve the accuracy of depth prediction. The application of templates in BZ oilfield shows that we achieve a high-precision depth prediction for underlying reservoir of shallow gas. For instance, the drilled well A shows that the predicted depth error using new method is only 3 meters while conventional predicted error is 10 meters. Therefore, we basically solve the problem of depth prediction and efficiently guide the drilling of development wells in BZ oilfield. We believe that the new method proposed here will be widely used in other oilfields containing shallow gas as well. The quality of seismic image of underlying strata is negatively affected by shallow gas. Seismic events below shallow gas are dominated by several special phenomena such as low frequency, drop-down and weak energy. Therefore, it is difficult to predict the depth of target zone accurately. Thus the drilling risk of horizontal wells is greatly raised as well. Currently, the influence of shallow gas on underlying strata is still under qualitative analysis. The purpose of this paper is to quantize the gas influence in order to provide a solution to achieve accurate depth prediction of target zone. In this paper, the influence mechanism of shallow gas on underlying strata is discussed in detail. Based on the discussion we find out main influential factors, including thickness of gas-bearing layer, horizontal scale of gas-bearing layer, buried depth of gas-bearing layer, distance between gas-bearing layer and target layer, receiving cable length and the formation velocity. With certain simplifications, we write a program to calculate the influence range and extent of shallow gas on underlying strata with main influential factors. Although there are some differences between simulation and the real situation, it is available to intuitively present the influence of shallow gas. Furthermore, we build many models based on different gas-bearing formation conditions to achieve pre-stack forward modeling with formation velocities derived from real drilling data in Bohai Bay Basin. Then we complete pre-stack time migration with shot records derived from forward modeling. Finally, we build a series of time correlation templates related to different offsets and depth of underlying strata through event auto-tracking and interpolation. The templates are applied to quantitatively estimate time correlation caused by shallow gas for any point of underlying strata, thus we achieve to improve the accuracy of depth prediction. The application of templates in BZ oilfield shows that we achieve a high-precision depth prediction for underlying reservoir of shallow gas. For instance, the drilled well A shows that the predicted depth error using new method is only 3 meters while conventional predicted error is 10 meters. Therefore, we basically solve the problem of depth prediction and efficiently guide the drilling of development wells in BZ oilfield. We believe that the new method proposed here will be widely used in other oilfields containing shallow gas as well. Panel_15490 Panel_15490 8:30 AM 5:00 PM

Subsurface injection of large-volume, high-pressure fluids is integral to fluid disposal. As these technologies develop, societal impacts and safety considerations require that subsurface storage scenarios proceed with site-specific risk assessments that include evaluation of the impacts of mechanical rock properties, stress orientations and an understanding of geo-tectonic history. Mechanical failure in rocks is a function of cohesive, tensile, and frictional strengths and the current and historic in situ stress. We examine mechanical rock properties from analog clastic rocks to determine their modified Coulomb-Griffith failure envelopes and apply these modeled failure envelopes to understand the rock failure potential at depth under conditions of increased pore pressure. Laboratory derived tensile rock strength data have a lithologic dependence; indirect tensile strength ranges from 2.3 MPa in siltstone to 11.5 MPa in calcareous shale. When combined with results from triaxial compressive rock strengths, which range from 6 MPa to 33 MPa, the shape change of the Coulomb-Griffith failure envelopes predict variability in the maximum pressures each intact rock type can withstand in the subsurface. The failure envelopes constrain the predicted mechanical behavior of the disposal reservoir and its seals. Associated top and bottom seal intervals respond to increased pore fluid pressure, and this response can be used in risk assessments for the reactivation of existing fractures or faults or creation of unintended hydrofractures within the injection reservoir or over/underlying seal lithologies. We combine rock material properties and the failure envelope variability with pressure data derived from evaluation of active injection wells where deep injection (0.5-6 km) occurs at maximum permitted injection pressures that range from 0.7 to 41 MPa. Incorporation of rock strength data helps predict the effect changes in intact rock strength have on fracture gradients and the potential for mechanical failure in the subsurface. Changes in cohesive and tensile strengths due to lateral and vertical anisotropy including lithological changes or the presence of fractures will result in variations in their associated failure envelopes and the fracture gradient. These types of analyses can be used to better constrain the conditions under which rocks fail and provide improved risk assessment of sequestration systems. Subsurface injection of large-volume, high-pressure fluids is integral to fluid disposal. As these technologies develop, societal impacts and safety considerations require that subsurface storage scenarios proceed with site-specific risk assessments that include evaluation of the impacts of mechanical rock properties, stress orientations and an understanding of geo-tectonic history. Mechanical failure in rocks is a function of cohesive, tensile, and frictional strengths and the current and historic in situ stress. We examine mechanical rock properties from analog clastic rocks to determine their modified Coulomb-Griffith failure envelopes and apply these modeled failure envelopes to understand the rock failure potential at depth under conditions of increased pore pressure. Laboratory derived tensile rock strength data have a lithologic dependence; indirect tensile strength ranges from 2.3 MPa in siltstone to 11.5 MPa in calcareous shale. When combined with results from triaxial compressive rock strengths, which range from 6 MPa to 33 MPa, the shape change of the Coulomb-Griffith failure envelopes predict variability in the maximum pressures each intact rock type can withstand in the subsurface. The failure envelopes constrain the predicted mechanical behavior of the disposal reservoir and its seals. Associated top and bottom seal intervals respond to increased pore fluid pressure, and this response can be used in risk assessments for the reactivation of existing fractures or faults or creation of unintended hydrofractures within the injection reservoir or over/underlying seal lithologies. We combine rock material properties and the failure envelope variability with pressure data derived from evaluation of active injection wells where deep injection (0.5-6 km) occurs at maximum permitted injection pressures that range from 0.7 to 41 MPa. Incorporation of rock strength data helps predict the effect changes in intact rock strength have on fracture gradients and the potential for mechanical failure in the subsurface. Changes in cohesive and tensile strengths due to lateral and vertical anisotropy including lithological changes or the presence of fractures will result in variations in their associated failure envelopes and the fracture gradient. These types of analyses can be used to better constrain the conditions under which rocks fail and provide improved risk assessment of sequestration systems. Panel_15486 Panel_15486 8:30 AM 5:00 PM

The mapping of shallow geohazards often demands special site surveys which provide sufficient resolution to delineate the hazards. Often, however, shallow geohazards are directly linked to deeper geological structures, which makes a seamless investigation from the seafloor down to deep geological structures desirable. The main obstacle preventing this seamless analysis has been insufficient signal-to-noise ratio, and low vertical and lateral resolution of geophysical data. A new method for analysis and interpretation is presented which maps the geophysical data into the color domain, allows the extraction of geological structures, and provides color texturing for the results. With this method the geologist can interpret geophysical data in a color environment, and obtain results which resemble the clarity and interpretability of satellite images for subsurface geological structures. Seafloor instabilities, shallow faults, and gas hydrates are delineated and studied in their structural and depositional context, providing a geological background for geohazard assessment from 3D geophysical data. The mapping of shallow geohazards often demands special site surveys which provide sufficient resolution to delineate the hazards. Often, however, shallow geohazards are directly linked to deeper geological structures, which makes a seamless investigation from the seafloor down to deep geological structures desirable. The main obstacle preventing this seamless analysis has been insufficient signal-to-noise ratio, and low vertical and lateral resolution of geophysical data. A new method for analysis and interpretation is presented which maps the geophysical data into the color domain, allows the extraction of geological structures, and provides color texturing for the results. With this method the geologist can interpret geophysical data in a color environment, and obtain results which resemble the clarity and interpretability of satellite images for subsurface geological structures. Seafloor instabilities, shallow faults, and gas hydrates are delineated and studied in their structural and depositional context, providing a geological background for geohazard assessment from 3D geophysical data. Panel_15484 Panel_15484 8:30 AM 5:00 PM

In January 2014, a panel of Alberta Energy Regulator (AER) hearing commissioners conducted an inquiry into odours and emissions from heavy oil and bitumen operations in the Peace River area of Alberta. In response to the regulatory panel’s recommendations, we were tasked with creating a 22000 km2 3D geological model, developing a sample program to address odour and source rock issues, and to evaluate the petroleum chemistry in a petroleum systems context. The model consists of 18 geological horizons spanning the surface digital elevation model (DEM) to the Precambrian basement. Elements incorporated into the model include wells, oil and gas pools, bitumen deposits, play areas, faults, geochemical data, petroleum chemical data, and satellite imagery. Various data were gathered using in-house and publicly available sources. Stratigraphic tops for over 25,000 wells were gathered from various sources to model the complex series of surfaces, including four major unconformities. The model was used to correlate produced petroleum chemistry to source rock petroleum chemistry, in an effort to predict where and why odours occur from some oil sands operations. A small sampling program was conducted to evaluate the geochemistry and petroleum chemistry of the Peace River area produced hydrocarbons, including the potentially odorous volatile organic compounds. This data was compared to hydrocarbons produced from other similar or related plays. The results of this project will be presented. These findings and similar workflows can be used to anticipate environmental impacts, and mitigate risks to the public and the environment through efficient and effective energy regulation. In addition, the 3D model has shown to be a good tool for communicating the information in a clear way to all the Stakeholders with various levels of background knowledge involved in the initial inquiries. In January 2014, a panel of Alberta Energy Regulator (AER) hearing commissioners conducted an inquiry into odours and emissions from heavy oil and bitumen operations in the Peace River area of Alberta. In response to the regulatory panel’s recommendations, we were tasked with creating a 22000 km² 3D geological model, developing a sample program to address odour and source rock issues, and to evaluate the petroleum chemistry in a petroleum systems context. The model consists of 18 geological horizons spanning the surface digital elevation model (DEM) to the Precambrian basement. Elements incorporated into the model include wells, oil and gas pools, bitumen deposits, play areas, faults, geochemical data, petroleum chemical data, and satellite imagery. Various data were gathered using in-house and publicly available sources. Stratigraphic tops for over 25,000 wells were gathered from various sources to model the complex series of surfaces, including four major unconformities. The model was used to correlate produced petroleum chemistry to source rock petroleum chemistry, in an effort to predict where and why odours occur from some oil sands operations. A small sampling program was conducted to evaluate the geochemistry and petroleum chemistry of the Peace River area produced hydrocarbons, including the potentially odorous volatile organic compounds. This data was compared to hydrocarbons produced from other similar or related plays. The results of this project will be presented. These findings and similar workflows can be used to anticipate environmental impacts, and mitigate risks to the public and the environment through efficient and effective energy regulation. In addition, the 3D model has shown to be a good tool for communicating the information in a clear way to all the Stakeholders with various levels of background knowledge involved in the initial inquiries. Panel_15480 Panel_15480 8:30 AM 5:00 PM

Studies to understand potential effects of hydraulic fracturing on human health and the environment are currently being done at the state and federal levels; however, none have included a human health risk assessment. We have undertaken a human health risk evaluation for spills, specifically focusing on potential risks to drinking water in basins underlain by formations targeted for oil and gas development via hydraulic fracturing. We use a probabilistic (Monte Carlo) framework that incorporates the distribution of potential spill volumes and environmental characteristics that influence the concentrations of hydraulic fracturing and flowback constituents for cases where a spill might reach a surface water or groundwater drinking water resource. The modeling also incorporates the likelihood of spills occurring and, if a spill occurs, the likelihood that containment or mitigation measures might capture the spill and prevent potential impacts on drinking water resources altogether. The results from the modeling are distributions of potential constituent concentrations in hypothetical surface water and groundwater resources. For comparison, the toxicity of 177 chemicals potentially present in 12 different HF fluid systems (including slickwater, gels, foams, and hybrids) and flowback fluid were evaluated to establish risk-based human health benchmarks. By taking the ratio of modeled concentrations to the health-based benchmarks, we performed a screening analysis to identify the likelihood that a spill might warrant further investigation with respect to potential human health effects via drinking water. Overall, our analysis demonstrates that there is an extremely low probability that an oil or gas well might have a spill that would warrant additional investigation with respect to potential human health effects. These findings are consistent with data from several states where studies have investigated potential impacts of hydraulic fracturing on surface water and groundwater. The broad range of environmental settings, fluid types, and spill scenarios considered in our analysis makes the results broadly applicable and helps provide some much needed perspective on the overall likelihood of the migration scenarios and potential risks. Studies to understand potential effects of hydraulic fracturing on human health and the environment are currently being done at the state and federal levels; however, none have included a human health risk assessment. We have undertaken a human health risk evaluation for spills, specifically focusing on potential risks to drinking water in basins underlain by formations targeted for oil and gas development via hydraulic fracturing. We use a probabilistic (Monte Carlo) framework that incorporates the distribution of potential spill volumes and environmental characteristics that influence the concentrations of hydraulic fracturing and flowback constituents for cases where a spill might reach a surface water or groundwater drinking water resource. The modeling also incorporates the likelihood of spills occurring and, if a spill occurs, the likelihood that containment or mitigation measures might capture the spill and prevent potential impacts on drinking water resources altogether. The results from the modeling are distributions of potential constituent concentrations in hypothetical surface water and groundwater resources. For comparison, the toxicity of 177 chemicals potentially present in 12 different HF fluid systems (including slickwater, gels, foams, and hybrids) and flowback fluid were evaluated to establish risk-based human health benchmarks. By taking the ratio of modeled concentrations to the health-based benchmarks, we performed a screening analysis to identify the likelihood that a spill might warrant further investigation with respect to potential human health effects via drinking water. Overall, our analysis demonstrates that there is an extremely low probability that an oil or gas well might have a spill that would warrant additional investigation with respect to potential human health effects. These findings are consistent with data from several states where studies have investigated potential impacts of hydraulic fracturing on surface water and groundwater. The broad range of environmental settings, fluid types, and spill scenarios considered in our analysis makes the results broadly applicable and helps provide some much needed perspective on the overall likelihood of the migration scenarios and potential risks. Panel_15482 Panel_15482 8:30 AM 5:00 PM

Constructing and operating Oil & Gas pipeline facilities and protecting the environment are not mutually exclusive. To be successful, we must proactively seek solutions that prevent releases and reduce impacts when an incident occurs. To do so requires a well coordinated spill response program involving a fully integrated system that incorporates risk reduction with spill response. There are typically four spill response phases. Industry refers to these as: Prevention, Preparedness, Response and Restoration. Spill prevention incorporates upfront risk reduction strategies with comprehensive response capabilities and begins by identifying liabilities and prioritizing areas most at risk. Detailed sensitivity mapping and modeling of spill flow paths for each concern identified during planning helps prioritize areas most at risk. Proper planning requires contingency and mitigation plans that protect highest risk assets and help ensure an immediate and well organized response, thus reducing ecological risk and community disruptions. Preparedness has no distinct beginning or end, but rather is an ongoing process involving proper training, organized teams of knowledgeable and competent staff, and the commitment of a company to be always ready. It includes pre-developed plans and support materials, regular training exercises, and experienced, qualified, and readily available subcontractors with strong backgrounds in health and safety. Response begins with the occurrence, incident notifications, and immediate mobilization of key personnel to the scene. Initial responders assess site conditions; identify additional personnel/equipment to initiate an effective and immediate response; and develop a preliminary containment and capture strategy of any fugitive release to mitigate further transport into the environment. In addition, responders determine if a public relations officer and/or community liaison are needed to assure stakeholders and the public are kept informed. A decision process such as the Net Environmental Benefit Analysis should be used for selecting appropriate response options when considering how and when to initiate restoration. This final phase is the first step in determining the timing and approach for restoring spill impacted areas and any potential impacts restoration activities themselves may contribute. Restoration usually occurs after completing response and cleanup activities, although undertaking early emergency restoration actions during a response often maximizes environmental benefits. In order to survive in the court of public opinion and protect shareholder value, companies must set a goal of responding to a release in a timely and efficient manner, allowing the protection of human health and the environment. This goal – in conjunction with available digital tools and the ICS system - is achievable when using the described approach. Constructing and operating Oil & Gas pipeline facilities and protecting the environment are not mutually exclusive. To be successful, we must proactively seek solutions that prevent releases and reduce impacts when an incident occurs. To do so requires a well coordinated spill response program involving a fully integrated system that incorporates risk reduction with spill response. There are typically four spill response phases. Industry refers to these as: Prevention, Preparedness, Response and Restoration. Spill prevention incorporates upfront risk reduction strategies with comprehensive response capabilities and begins by identifying liabilities and prioritizing areas most at risk. Detailed sensitivity mapping and modeling of spill flow paths for each concern identified during planning helps prioritize areas most at risk. Proper planning requires contingency and mitigation plans that protect highest risk assets and help ensure an immediate and well organized response, thus reducing ecological risk and community disruptions. Preparedness has no distinct beginning or end, but rather is an ongoing process involving proper training, organized teams of knowledgeable and competent staff, and the commitment of a company to be always ready. It includes pre-developed plans and support materials, regular training exercises, and experienced, qualified, and readily available subcontractors with strong backgrounds in health and safety. Response begins with the occurrence, incident notifications, and immediate mobilization of key personnel to the scene. Initial responders assess site conditions; identify additional personnel/equipment to initiate an effective and immediate response; and develop a preliminary containment and capture strategy of any fugitive release to mitigate further transport into the environment. In addition, responders determine if a public relations officer and/or community liaison are needed to assure stakeholders and the public are kept informed. A decision process such as the Net Environmental Benefit Analysis should be used for selecting appropriate response options when considering how and when to initiate restoration. This final phase is the first step in determining the timing and approach for restoring spill impacted areas and any potential impacts restoration activities themselves may contribute. Restoration usually occurs after completing response and cleanup activities, although undertaking early emergency restoration actions during a response often maximizes environmental benefits. In order to survive in the court of public opinion and protect shareholder value, companies must set a goal of responding to a release in a timely and efficient manner, allowing the protection of human health and the environment. This goal – in conjunction with available digital tools and the ICS system - is achievable when using the described approach. Panel_15487 Panel_15487 8:30 AM 5:00 PM

Shallow gas in the Dutch sector of the North Sea has largely been encountered in marginal marine clastic deposits of the Plio-Pleistocene Eridanos delta. However, the origin of this shallow gas is not well understood. The shallow gas may originate solely from biogenic bacterial alteration. However, it is difficult to distinguish truly biogenic gas from thermogenic gas altered by shallow bacterial processes. Disturbed zones indicating potential gas chimneys were noted below the shallow gas anomalies. However, it was difficult without additional analysis to determine if this seismic response represented true vertical gas migration or was a seismic processing artifact. A gas chimney detection project was undertaken in the 3D seismic survey to assess the reliability of the suspected chimneys, determine from which interval they originated, and how they were linked to the shallow gas occurrences. By understanding the hydrocarbon migration pathways we should be able to delineate deep prospective traps and high grade additional shallow gas leads. Gas chimneys were detected using a supervised neural network trained on reliable examples of gas chimneys. The resultant chimneys were validated based on a set of criteria used in many studies. Results of the study indicate that chimneys providing charge to the shallow gas sands are generally reliable. The chimneys originate from a Carboniferous gas-prone source rock interval that can be directly linked to the shallow gas sands. Gas migrated vertically from the Paleozoic interval through faults in the Upper Permian Zechstein Salt. We observe gas clouds over some of the shallow channel reservoirs, indicating they are fully saturated with gas. The results of this study have three important implications for successful gas exploration in this sector of the North Sea. First, the study highlights deep vertical gas migration pathways which provide charge to prospective Triassic reservoir objectives. Second, the study highlights vertical gas migration pathways which provide preferential charge to shallow reservoirs. Third, the study provides clues about the top seal integrity of the shallow traps. Top seal integrity is a critical risk in the poorly consolidated shallow sands. Breached traps can still have strong AVO anomalies due to “fizz gas”. The morphology of gas chimneys above the trap (gas cloud or fault related) provides important clues about the top seal integrity. Shallow gas in the Dutch sector of the North Sea has largely been encountered in marginal marine clastic deposits of the Plio-Pleistocene Eridanos delta. However, the origin of this shallow gas is not well understood. The shallow gas may originate solely from biogenic bacterial alteration. However, it is difficult to distinguish truly biogenic gas from thermogenic gas altered by shallow bacterial processes. Disturbed zones indicating potential gas chimneys were noted below the shallow gas anomalies. However, it was difficult without additional analysis to determine if this seismic response represented true vertical gas migration or was a seismic processing artifact. A gas chimney detection project was undertaken in the 3D seismic survey to assess the reliability of the suspected chimneys, determine from which interval they originated, and how they were linked to the shallow gas occurrences. By understanding the hydrocarbon migration pathways we should be able to delineate deep prospective traps and high grade additional shallow gas leads. Gas chimneys were detected using a supervised neural network trained on reliable examples of gas chimneys. The resultant chimneys were validated based on a set of criteria used in many studies. Results of the study indicate that chimneys providing charge to the shallow gas sands are generally reliable. The chimneys originate from a Carboniferous gas-prone source rock interval that can be directly linked to the shallow gas sands. Gas migrated vertically from the Paleozoic interval through faults in the Upper Permian Zechstein Salt. We observe gas clouds over some of the shallow channel reservoirs, indicating they are fully saturated with gas. The results of this study have three important implications for successful gas exploration in this sector of the North Sea. First, the study highlights deep vertical gas migration pathways which provide charge to prospective Triassic reservoir objectives. Second, the study highlights vertical gas migration pathways which provide preferential charge to shallow reservoirs. Third, the study provides clues about the top seal integrity of the shallow traps. Top seal integrity is a critical risk in the poorly consolidated shallow sands. Breached traps can still have strong AVO anomalies due to “fizz gas”. The morphology of gas chimneys above the trap (gas cloud or fault related) provides important clues about the top seal integrity. Panel_15485 Panel_15485 8:30 AM 5:00 PM

Saline waters co-produced from both unconventional shale gas and conventional sandstone wells provide a unique opportunity to investigate sources of the formation brines and water rock interactions. In this study, multi-collector ICPMS was used to measure lithium isotope ratios (?7Li) in water and whole rock samples from hydraulically fractured wells in the Marcellus shale (Middle Devonian), and water from conventional wells producing from Upper Devonian sandstones. The distribution of lithium concentration in different minerals was determined using sequential extraction techniques. The results show that Li is primarily associated with silicate minerals. Structurally bound Li accounted for 75-91% by weight whereas exchangeable Li is less than 2%. In the Marcellus Shale, the main sink for Li is uptake by clays whereas carbonate cement contains negligible amounts of Li (< 2%). ?7Li values of shale whole rocks in both Greene Co., Pennsylvania and Tioga Co., New York ranged from -2.3‰ to +4.3‰, similar to values reported for shales in the literature. Time-series samples of Marcellus Shale water in southwestern Pennsylvania showed that both Li concentrations and ?7Li increased over the first 45 days of production then remained constant ([Li]=98±5 mg/L; ?7Li=10.3±0.2‰, 2SD) for 27 months of continued sampling. The initial trend can be explained by mixing of isotopically light Li in the injected fluid with formation brine containing high concentrations of isotopically heavier Li. The U. Devonian sandstone brines (Greene Co.) have ?7Li values in a narrow range (+13.7‰ to +15.4‰) and are distinct from Marcellus Shale produced waters from the same region (+7.63‰ to +10.5‰). This suggests minimal present migration of brine from Marcellus brines and deeper units upward into the overlying U. Devonian sandstones. Marcellus brines from Tioga Co., north-central Pennsylvania, contain more Li (208-233 mg/L) and isotopically heavier Li (14.3‰ to 15.0‰) than those in southwestern Pennsylvania. Our preliminary data for Marcellus Shale produced water suggest regional differences in the Li concentration and isotopic ratios, possibly reflecting differences in sources, the original water trapped in the shale fractures, diagenetic processes, thermal histories, or paleo-fluid flow pathways. Saline waters co-produced from both unconventional shale gas and conventional sandstone wells provide a unique opportunity to investigate sources of the formation brines and water rock interactions. In this study, multi-collector ICPMS was used to measure lithium isotope ratios (?7Li) in water and whole rock samples from hydraulically fractured wells in the Marcellus shale (Middle Devonian), and water from conventional wells producing from Upper Devonian sandstones. The distribution of lithium concentration in different minerals was determined using sequential extraction techniques. The results show that Li is primarily associated with silicate minerals. Structurally bound Li accounted for 75-91% by weight whereas exchangeable Li is less than 2%. In the Marcellus Shale, the main sink for Li is uptake by clays whereas carbonate cement contains negligible amounts of Li (< 2%). ?7Li values of shale whole rocks in both Greene Co., Pennsylvania and Tioga Co., New York ranged from -2.3‰ to +4.3‰, similar to values reported for shales in the literature. Time-series samples of Marcellus Shale water in southwestern Pennsylvania showed that both Li concentrations and ?7Li increased over the first 45 days of production then remained constant ([Li]=98±5 mg/L; ?7Li=10.3±0.2‰, 2SD) for 27 months of continued sampling. The initial trend can be explained by mixing of isotopically light Li in the injected fluid with formation brine containing high concentrations of isotopically heavier Li. The U. Devonian sandstone brines (Greene Co.) have ?7Li values in a narrow range (+13.7‰ to +15.4‰) and are distinct from Marcellus Shale produced waters from the same region (+7.63‰ to +10.5‰). This suggests minimal present migration of brine from Marcellus brines and deeper units upward into the overlying U. Devonian sandstones. Marcellus brines from Tioga Co., north-central Pennsylvania, contain more Li (208-233 mg/L) and isotopically heavier Li (14.3‰ to 15.0‰) than those in southwestern Pennsylvania. Our preliminary data for Marcellus Shale produced water suggest regional differences in the Li concentration and isotopic ratios, possibly reflecting differences in sources, the original water trapped in the shale fractures, diagenetic processes, thermal histories, or paleo-fluid flow pathways. Panel_15481 Panel_15481 8:30 AM 5:00 PM

Panel_14496 Panel_14496 8:30 AM 5:00 PM

The geological effects on methane adsorption capacity for the Jurassic continental shales in the Tarim Basin, Northwestern China, have been investigated in this paper compared to the marine gas shales in the North Amarica and the South China. The methane adsorption capacity ranges from 0.58 cm3/g to 16.57 cm3/g and the total organic carbon (TOC) content is between 0.5 wt% and 13.5 wt%. The organic maturity measured by Tmax is between 410 °C (immature) and 499 °C (overmature). The methane adsorption capacity of the Jurassic continental shales in Tarim Basin is affected by many geological factors, including the TOC content, organic matter maturity, mineral composition, surface area, pore size distribution, etc. The TOC content is the most significant factor with a positive effect on the adsorption capacity of the Jurassic shales, and the influence varies piecewise according to the TOC content. The TOC content contributes much more to the methane adsorption capacity of organic-rich shale samples (TOC content > 0.7 wt%) than to the organic-lean samples (TOC content < 0.7 wt%). The mineral composition is a secondary factor, and the abundance of clay content has a positive effect on the methane adsorption capacity despite its relatively weaker adsorption ability compared to TOC. The pore size distribution has different effects on surface area and pore volume. Mesopores and micropores provide the major surface area and are mainly derives from TOC and illite, which has a positive influence on the adsorption capacity. Mesopores and macropores offer the major pore volume and are mainly formed by illite, which is the major contributor for pore volume rather than surface area. Besides, the TOC and illite contents of the Jurassic shales in Tarim Basin are closely related to the origin, maturity and diagenesis evolution of the shale: 1) both TOC and illite contents variations are related to the different provenances and depositional environments of shale; 2) the decrease of TOC content with increasing maturity is also partly attributed to hydrocarbon generation; and 3) the increase of illite content with increasing maturity is due to illitization in the diagenesis of shale. The geological effects on methane adsorption capacity for the Jurassic continental shales in the Tarim Basin, Northwestern China, have been investigated in this paper compared to the marine gas shales in the North Amarica and the South China. The methane adsorption capacity ranges from 0.58 cm3/g to 16.57 cm3/g and the total organic carbon (TOC) content is between 0.5 wt% and 13.5 wt%. The organic maturity measured by Tmax is between 410 °C (immature) and 499 °C (overmature). The methane adsorption capacity of the Jurassic continental shales in Tarim Basin is affected by many geological factors, including the TOC content, organic matter maturity, mineral composition, surface area, pore size distribution, etc. The TOC content is the most significant factor with a positive effect on the adsorption capacity of the Jurassic shales, and the influence varies piecewise according to the TOC content. The TOC content contributes much more to the methane adsorption capacity of organic-rich shale samples (TOC content > 0.7 wt%) than to the organic-lean samples (TOC content < 0.7 wt%). The mineral composition is a secondary factor, and the abundance of clay content has a positive effect on the methane adsorption capacity despite its relatively weaker adsorption ability compared to TOC. The pore size distribution has different effects on surface area and pore volume. Mesopores and micropores provide the major surface area and are mainly derives from TOC and illite, which has a positive influence on the adsorption capacity. Mesopores and macropores offer the major pore volume and are mainly formed by illite, which is the major contributor for pore volume rather than surface area. Besides, the TOC and illite contents of the Jurassic shales in Tarim Basin are closely related to the origin, maturity and diagenesis evolution of the shale: 1) both TOC and illite contents variations are related to the different provenances and depositional environments of shale; 2) the decrease of TOC content with increasing maturity is also partly attributed to hydrocarbon generation; and 3) the increase of illite content with increasing maturity is due to illitization in the diagenesis of shale. Panel_15595 Panel_15595 8:30 AM 5:00 PM

The majority of the Marcellus Shale in the Appalachian Basin is a proven hydrocarbon producing reservoir with repeatable production results. These results are related to the geologic parameters of the shale in an area as well as the completion techniques applied to a given well. However, portions of the Marcellus Shale, specifically those deposits residing near the Allegheny Structural Front, have undergone folding and faulting related to Alleghenian tectonism which allowed hydrocarbons to escape through geologic time. The variable migration of hydrocarbons out of the system is manifested as inconsistent production results from wells at some proximity to mapped faults. This study compares the methane and ethane isotopic signatures of Marcellus Shale production from wells in structurally complex and structurally benign geologic settings. In a normal maturation trend, the methane and ethane isotopes show isotopic reversal at higher thermal maturities. Methane and ethane isotopes in structural complex areas trend isotopically lighter than would be expected based on the shale’s thermal maturity. When these isotopic signatures are evaluated relative to thermal maturity parameters such as vitrinite reflectance, relationships indicate the gases have experienced a fractionation of the isotopes during folding and faulting events and/or the isotopes preserve the composition of the methane and ethane when the structural event occurred. In the more structurally complex areas these isotopic signatures may be attributed to increased migration out of the source rock over geologic time. The majority of the Marcellus Shale in the Appalachian Basin is a proven hydrocarbon producing reservoir with repeatable production results. These results are related to the geologic parameters of the shale in an area as well as the completion techniques applied to a given well. However, portions of the Marcellus Shale, specifically those deposits residing near the Allegheny Structural Front, have undergone folding and faulting related to Alleghenian tectonism which allowed hydrocarbons to escape through geologic time. The variable migration of hydrocarbons out of the system is manifested as inconsistent production results from wells at some proximity to mapped faults. This study compares the methane and ethane isotopic signatures of Marcellus Shale production from wells in structurally complex and structurally benign geologic settings. In a normal maturation trend, the methane and ethane isotopes show isotopic reversal at higher thermal maturities. Methane and ethane isotopes in structural complex areas trend isotopically lighter than would be expected based on the shale’s thermal maturity. When these isotopic signatures are evaluated relative to thermal maturity parameters such as vitrinite reflectance, relationships indicate the gases have experienced a fractionation of the isotopes during folding and faulting events and/or the isotopes preserve the composition of the methane and ethane when the structural event occurred. In the more structurally complex areas these isotopic signatures may be attributed to increased migration out of the source rock over geologic time. Panel_15588 Panel_15588 8:30 AM 5:00 PM

An iterative cycle of petroleum systems interpretations provides two supporting lines of evidence of the asymmetric opening of the Atlantic Equatorial Margins: the tectono-structural evolution and hydrocarbon geochemistry. Research on evolution of Atlantic ocean crust and margin basins has clarified the tectono-structural history of the conjugate passive margins and associated Equatorial Transform Margins. Given the prominent structural asymmetry of the passive margins, we anticipated asymmetry along the Equatorial Margin. We investigated the region with new compilations of high resolution geophysical data and comparisons of oil geochemistries from both margins. An initial suite of 1467 oil samples spanned the southern Central Atlantic plus Equatorial and South Atlantic margins. After analysis to establish a South Atlantic framework, we selected a subset of 387 samples from the Equatorial Margins. Reliability tests of oil family assignments continued by inspecting spatial relationships versus basin shapes. Tectono-structural interpretation from our geophysical data and published knowledge of basin and reservoir temperatures helped define where there was sufficient burial depth for maturity of each source and where structural features would block or guide hydrocarbon migration. Non-Cretaceous sourced oils like those of the Niger Delta (Tertiary) or Dahomey Embayment (Paleozoic) were excluded and after twenty iterations, the set was reduced to 284 oils. Fourteen (14) parameters accounted for 65% of sample variance and five broad groups of compositionally similar oils (A - E) were identified of which only Family E is represented along the West African Transform (WAT) Margin. Equatorial Atlantic opening was asymmetric with deep monoclinal basins along the WAT Margin between St Paul and Chain Fracture Zones while the Brazilian-Guyanan conjugates retained most of the early syn-rift architecture. Hence the opening asymmetry a) biased the location of potential lacustrine (early to mid-Cretaceous pre-rift to early syn-rift) source and b) locally narrowed the width of optimal marine (Mid to Late Cretaceous post-rift) kitchens. The latter, where rapidly buried offshore Ivory Coast-Ghana, contribute to a risk of late charge from light hydrocarbons. Finding a rich, more oil-prone lacustrine source would be a surprise along the WAT Margin where we see minor evidence of mixed source, possibly lacustrine stringers within an alluvial to marine setting. An iterative cycle of petroleum systems interpretations provides two supporting lines of evidence of the asymmetric opening of the Atlantic Equatorial Margins: the tectono-structural evolution and hydrocarbon geochemistry. Research on evolution of Atlantic ocean crust and margin basins has clarified the tectono-structural history of the conjugate passive margins and associated Equatorial Transform Margins. Given the prominent structural asymmetry of the passive margins, we anticipated asymmetry along the Equatorial Margin. We investigated the region with new compilations of high resolution geophysical data and comparisons of oil geochemistries from both margins. An initial suite of 1467 oil samples spanned the southern Central Atlantic plus Equatorial and South Atlantic margins. After analysis to establish a South Atlantic framework, we selected a subset of 387 samples from the Equatorial Margins. Reliability tests of oil family assignments continued by inspecting spatial relationships versus basin shapes. Tectono-structural interpretation from our geophysical data and published knowledge of basin and reservoir temperatures helped define where there was sufficient burial depth for maturity of each source and where structural features would block or guide hydrocarbon migration. Non-Cretaceous sourced oils like those of the Niger Delta (Tertiary) or Dahomey Embayment (Paleozoic) were excluded and after twenty iterations, the set was reduced to 284 oils. Fourteen (14) parameters accounted for 65% of sample variance and five broad groups of compositionally similar oils (A - E) were identified of which only Family E is represented along the West African Transform (WAT) Margin. Equatorial Atlantic opening was asymmetric with deep monoclinal basins along the WAT Margin between St Paul and Chain Fracture Zones while the Brazilian-Guyanan conjugates retained most of the early syn-rift architecture. Hence the opening asymmetry a) biased the location of potential lacustrine (early to mid-Cretaceous pre-rift to early syn-rift) source and b) locally narrowed the width of optimal marine (Mid to Late Cretaceous post-rift) kitchens. The latter, where rapidly buried offshore Ivory Coast-Ghana, contribute to a risk of late charge from light hydrocarbons. Finding a rich, more oil-prone lacustrine source would be a surprise along the WAT Margin where we see minor evidence of mixed source, possibly lacustrine stringers within an alluvial to marine setting. Panel_15596 Panel_15596 8:30 AM 5:00 PM

Crude oil and natural gas can carry various high-impurity products which are inherently corrosive such as carbon dioxide (CO2) and hydrogen sulfide (H2S). These impurities increase operations safety risk and can be detrimental to production both in terms of equipment damage and permeability impairment by scale build up. Problems with FeS containing scale build occur when H2S comes in contact with spent acid solutions containing dissolved iron ions. While dissolution of pipeline and iron bearing core materials in H2S solutions is known to result in FeS scale build up, reactivity of iron containing proppant material under sour conditions is poorly understood and documented. Here presented study evaluates and compares dissolution kinetics of pipeline material, iron bearing formation and iron containing proppants in H2S acid solution in order to evaluate their relative contribution to FeS containing scale build up. Study uses X-ray diffraction (XRD), X-ray fluorescence (XRF) analysis and inductively-coupled plasma atomic emission spectroscopy (ICP-AES) analysis to qualify present Fe containing crystallite forms and quantify dissolution and scale build up reaction kinetic. Scanning electron Microscopy (SEM) evaluates surface morphology changes associated with iron dissolution and FeS scale build up. Finally reactivity of all tested materials is compared based on their initial iron concentration and relative dissolution affinity. Effects of FeS scale build up on EUR and proppant cost related ROI is also discussed. Crude oil and natural gas can carry various high-impurity products which are inherently corrosive such as carbon dioxide (CO₂) and hydrogen sulfide (H2S). These impurities increase operations safety risk and can be detrimental to production both in terms of equipment damage and permeability impairment by scale build up. Problems with FeS containing scale build occur when H2S comes in contact with spent acid solutions containing dissolved iron ions. While dissolution of pipeline and iron bearing core materials in H2S solutions is known to result in FeS scale build up, reactivity of iron containing proppant material under sour conditions is poorly understood and documented. Here presented study evaluates and compares dissolution kinetics of pipeline material, iron bearing formation and iron containing proppants in H2S acid solution in order to evaluate their relative contribution to FeS containing scale build up. Study uses X-ray diffraction (XRD), X-ray fluorescence (XRF) analysis and inductively-coupled plasma atomic emission spectroscopy (ICP-AES) analysis to qualify present Fe containing crystallite forms and quantify dissolution and scale build up reaction kinetic. Scanning electron Microscopy (SEM) evaluates surface morphology changes associated with iron dissolution and FeS scale build up. Finally reactivity of all tested materials is compared based on their initial iron concentration and relative dissolution affinity. Effects of FeS scale build up on EUR and proppant cost related ROI is also discussed. Panel_15591 Panel_15591 8:30 AM 5:00 PM

Embedded in regional exploration workflows is generally a strong preference for prospects to be located on the continental crust. The main logic in this rule of thumb is that continental crust generates 10-100 times more radioactive heat per volume than oceanic crust and, therefore, ensures sufficiently warm thermal history of source rocks within sedimentary section to mature and generate hydrocarbons. Neglected in this reasoning is a fact that thermal history of a basin is a function of not only basement heat flow history, but also sediment thermal properties and depositional history. Although overall thermal history of sediments deposited on the oceanic crust tend to be cooler than over the continental crust, it does not automatically prevent source rock maturation. In this study we investigate a number of crustal type, crustal and sedimentary thickness scenarios and their impact on hydrocarbon generation. We consider a basin with a rifting period during 100-90 Ma and continuous siliciclastic sedimentation to present-day. The results of basin modeling indicate, for example, that over the thinned continental and oceanic crusts the potential source rocks would reach their maturity of 1% VRo (mid-range of oil window) at present day ~3-km and ~5-km depths, respectively. These estimates support presence of sufficient heat flow for hydrocarbon generation in areas of thick sedimentary deposits over the oceanic crust. Although exceptional, well-known examples of the basins with sedimentary thickness exceeding 5 km over the oceanic crust are the Foz do Amazonas and Niger Delta. Exploration geologists commonly use rules of thumb to help them quickly screen a basin. Limitations and uncertainties of such rules are often underestimated and not considered. Moreover, initial incorrect perceptions about basin history may persist even though later basin models may indicate a different story. This happens because basin model is typically built later in the exploration workflow after “all the geology” is put together. Our example illustrates the need for performing a numerical integration early in, and throughout, the exploration workflow and keeping in mind that rules have their exceptions. Embedded in regional exploration workflows is generally a strong preference for prospects to be located on the continental crust. The main logic in this rule of thumb is that continental crust generates 10-100 times more radioactive heat per volume than oceanic crust and, therefore, ensures sufficiently warm thermal history of source rocks within sedimentary section to mature and generate hydrocarbons. Neglected in this reasoning is a fact that thermal history of a basin is a function of not only basement heat flow history, but also sediment thermal properties and depositional history. Although overall thermal history of sediments deposited on the oceanic crust tend to be cooler than over the continental crust, it does not automatically prevent source rock maturation. In this study we investigate a number of crustal type, crustal and sedimentary thickness scenarios and their impact on hydrocarbon generation. We consider a basin with a rifting period during 100-90 Ma and continuous siliciclastic sedimentation to present-day. The results of basin modeling indicate, for example, that over the thinned continental and oceanic crusts the potential source rocks would reach their maturity of 1% VRo (mid-range of oil window) at present day ~3-km and ~5-km depths, respectively. These estimates support presence of sufficient heat flow for hydrocarbon generation in areas of thick sedimentary deposits over the oceanic crust. Although exceptional, well-known examples of the basins with sedimentary thickness exceeding 5 km over the oceanic crust are the Foz do Amazonas and Niger Delta. Exploration geologists commonly use rules of thumb to help them quickly screen a basin. Limitations and uncertainties of such rules are often underestimated and not considered. Moreover, initial incorrect perceptions about basin history may persist even though later basin models may indicate a different story. This happens because basin model is typically built later in the exploration workflow after “all the geology” is put together. Our example illustrates the need for performing a numerical integration early in, and throughout, the exploration workflow and keeping in mind that rules have their exceptions. Panel_15584 Panel_15584 8:30 AM 5:00 PM

Sixty-nine crude oils from wells in the southeastern Denver Basin and Las Animas Arch areas are grouped into three major oil families based on genetic-specific biomarkers and stable carbon isotope compositions using multivariate statistics. These oils are largely distinguished by sterane distributions, biomarkers for different algal populations. High amounts of C28 steranes are very unusual for Paleozoic source rocks (Family 1) while high C27 steranes with upwelling signatures are more common in oils generated regionally from Middle Pennsylvanian sources (Family 3). Higher C29 steranes often indicate a component of terrigenous, coaly sources, consistent with the waxy character of some Family 2 oils. Since Sub-families 3a & 3b are almost exclusively produced from Middle Pennsylvanian reservoirs and 80% of Sub-families 1a & 1b oils are from Mississippian reservoirs, it is fair to propose that source horizons for these families are also Middle Pennsylvanian and Mississippian, respectively. Many of Family 2 waxy oils are reservoired in, and likely sourced, in part, from the Lower Pennsylvanian Morrow Formation. Pennsylvanian source rocks for Family 3 oils were deposited under the influence of strong and persistent upwelling conditions, promoting high phytoplankton productivity. Oils that contain abundant aryl isoprenoids – only Family 3 – suggest shallow water anoxia and enhanced preservation of source organic matter. Family 3a oils in Pennsylvanian reservoirs, likely generated from Desmoinesian source marls, occur only on the northwestern flank of the Las Animas Arch and within the Denver Basin. These oils originated and migrated from Denver Basin depocenters. Pennsylvanian Family 3b oils only occur on the eastern flank of the Arch. These are likely derived from depocenters to the east, perhaps deeper within the Hugoton Embayment. Similarly, Family 1b oils in Mississippian reservoirs, likely sourced from Mississippian shales, occur exclusively on the eastern flank of the Las Animas Arch and are, again, likely derived from depocenters to the east. Morrow Family 2 oils only occur in the Denver Basin. A number of maturity-sensitive biomarker ratios were subjected to principal component analysis and converted into an vitrinite reflectance equivalent (VRE) values. Mississippian shale source rocks to the east of the Arch generated oil in the 0.82-0.90% VRE range. In contrast, the Pennsylvanian-sourced oils were generated at lower levels of maturity, 0.69-0.74% VRE. Sixty-nine crude oils from wells in the southeastern Denver Basin and Las Animas Arch areas are grouped into three major oil families based on genetic-specific biomarkers and stable carbon isotope compositions using multivariate statistics. These oils are largely distinguished by sterane distributions, biomarkers for different algal populations. High amounts of C28 steranes are very unusual for Paleozoic source rocks (Family 1) while high C27 steranes with upwelling signatures are more common in oils generated regionally from Middle Pennsylvanian sources (Family 3). Higher C29 steranes often indicate a component of terrigenous, coaly sources, consistent with the waxy character of some Family 2 oils. Since Sub-families 3a & 3b are almost exclusively produced from Middle Pennsylvanian reservoirs and 80% of Sub-families 1a & 1b oils are from Mississippian reservoirs, it is fair to propose that source horizons for these families are also Middle Pennsylvanian and Mississippian, respectively. Many of Family 2 waxy oils are reservoired in, and likely sourced, in part, from the Lower Pennsylvanian Morrow Formation. Pennsylvanian source rocks for Family 3 oils were deposited under the influence of strong and persistent upwelling conditions, promoting high phytoplankton productivity. Oils that contain abundant aryl isoprenoids – only Family 3 – suggest shallow water anoxia and enhanced preservation of source organic matter. Family 3a oils in Pennsylvanian reservoirs, likely generated from Desmoinesian source marls, occur only on the northwestern flank of the Las Animas Arch and within the Denver Basin. These oils originated and migrated from Denver Basin depocenters. Pennsylvanian Family 3b oils only occur on the eastern flank of the Arch. These are likely derived from depocenters to the east, perhaps deeper within the Hugoton Embayment. Similarly, Family 1b oils in Mississippian reservoirs, likely sourced from Mississippian shales, occur exclusively on the eastern flank of the Las Animas Arch and are, again, likely derived from depocenters to the east. Morrow Family 2 oils only occur in the Denver Basin. A number of maturity-sensitive biomarker ratios were subjected to principal component analysis and converted into an vitrinite reflectance equivalent (VRE) values. Mississippian shale source rocks to the east of the Arch generated oil in the 0.82-0.90% VRE range. In contrast, the Pennsylvanian-sourced oils were generated at lower levels of maturity, 0.69-0.74% VRE. Panel_15589 Panel_15589 8:30 AM 5:00 PM

Recent exploration for unconventional hydrocarbon resources in British Columbia with abundant shale intervals leads to increase British Columbia’s natural gas resources. However, higher economic value of gas condensates attracts higher attention to the formations in the gas condensate zone. The present study reports the high resolution organic matter characterization of subsurface samples of the Lower Cretaceous Garbutt Formation obtained from 3 cores in the eastern part of Liard Basin. The Garbutt Formation consists of black, silty shale and mudrock. Samples are from 3 wells in a north to south direction parallel to the eastern margin of Liard Basin in the vicinity of Bovie fault, at depths ranging from 1200 to 1400m. High percentage of farmboidal pyrite (Up to 30%), high Mo and U concentration of Garbutt Formation in two upper wells indicate a euxinic environment during deposition. The majority of samples have very good to excellent TOC content ranging from 1.1 to 10.3% with an average of 4.3%. The current TOC content of samples represents 75-88% of the residual carbon with an increasing trend from north to south. The Tmax values obtained from the Rock-Eval analysis ranges from 432 to 470°C which represent the onset of the oil window to the onset of the dry gas window toward south. Samples in the oil window with high S2 values exude oil under fluorescent light. The maceral group composition of these samples appears to reflect the thermal maturity populations. Those samples in the lowest maturity zone are predominately liptinite group macerals (alginate) (64%), with 25% vitrinite and 11% inertinite group macerals by volume. Samples within the middle population of maturity contain 44% liptinite group macerals (alginate), with higher vitrinite at (40%), and low inertinite (16%). Samples with the highest maturity, are rich in vitrinite (41%) and inertinite group (37.5%) macerals, and lower in liptinite group macerals (liptodetrinite) at 21.5%. Vitrinite reflectance (VRo) was measured in these samples and exhibit a slight variation in thermal maturity compared to Tmax values. Samples with lower maturity show two distinct vitrinite populations, one with an average peak of 0.75%, the other with an average peak of 1.08%. Within samples with higher maturity, these two populations are far closer, with greatly overlapping measurement distribution, with peaks at 1.49%, and 1.31%, respectively. Recent exploration for unconventional hydrocarbon resources in British Columbia with abundant shale intervals leads to increase British Columbia’s natural gas resources. However, higher economic value of gas condensates attracts higher attention to the formations in the gas condensate zone. The present study reports the high resolution organic matter characterization of subsurface samples of the Lower Cretaceous Garbutt Formation obtained from 3 cores in the eastern part of Liard Basin. The Garbutt Formation consists of black, silty shale and mudrock. Samples are from 3 wells in a north to south direction parallel to the eastern margin of Liard Basin in the vicinity of Bovie fault, at depths ranging from 1200 to 1400m. High percentage of farmboidal pyrite (Up to 30%), high Mo and U concentration of Garbutt Formation in two upper wells indicate a euxinic environment during deposition. The majority of samples have very good to excellent TOC content ranging from 1.1 to 10.3% with an average of 4.3%. The current TOC content of samples represents 75-88% of the residual carbon with an increasing trend from north to south. The Tmax values obtained from the Rock-Eval analysis ranges from 432 to 470°C which represent the onset of the oil window to the onset of the dry gas window toward south. Samples in the oil window with high S2 values exude oil under fluorescent light. The maceral group composition of these samples appears to reflect the thermal maturity populations. Those samples in the lowest maturity zone are predominately liptinite group macerals (alginate) (64%), with 25% vitrinite and 11% inertinite group macerals by volume. Samples within the middle population of maturity contain 44% liptinite group macerals (alginate), with higher vitrinite at (40%), and low inertinite (16%). Samples with the highest maturity, are rich in vitrinite (41%) and inertinite group (37.5%) macerals, and lower in liptinite group macerals (liptodetrinite) at 21.5%. Vitrinite reflectance (VRo) was measured in these samples and exhibit a slight variation in thermal maturity compared to Tmax values. Samples with lower maturity show two distinct vitrinite populations, one with an average peak of 0.75%, the other with an average peak of 1.08%. Within samples with higher maturity, these two populations are far closer, with greatly overlapping measurement distribution, with peaks at 1.49%, and 1.31%, respectively. Panel_15587 Panel_15587 8:30 AM 5:00 PM

The Utica-Pt. Pleasant unconventional play produces gas and condensate in eastern Ohio and western Pennsylvania. Condensate yield is important to the commercial success of the play, so there is in interest in improving the pre-drill prediction of this parameter. In general, measured and modeled maturity can be used as a predictive tool to distinguish areas prospective for oil, wet gas and dry gas for unconventional plays. Usually oil is found in the 0.6-1.1 Ro range, wet gas from 1.1-1.7 and dry gas over 1.7. In this case we attempt to predict condensate yield rather than just wet gas based on a range of modeled maturity. A 3D maturity model of the Utica-Point Pleasant Basin was constructed in order to predict maturity (vitrinite reflectance equivalence or VRE) for multiple stratigraphic horizons. The horizons modeled were the Berea, Marcellus, Top Ordovician, Utica, Top Knox, Base Knox and Basement. In addition to structural horizons a map estimating late Paleozoic erosion was constructed. An uncorrected temperature gradient map from bottom hole temperatures from nearly 1500 wells was also made. This map was adjusted to correlate the Utica-Point Pleasant modeled maturity to the rock maturity for this interval. Utica-Point Pleasant model maturity to rock maturity correlation coefficient was about .50. This calibrated temperature gradient map was then used to model the other six horizons. Condensate yield was calculated from Utica-Point Pleasant production data for 256 wells provided by the Ohio Department of Natural Resources. These condensate yields were correlated to Utica-Pt. Pleasant modeled maturity and a good correlation (R2 = .76) was found between these data sets. The Utica-Point Pleasant modeled maturity map was then transformed to a condensate yield map by means of the equation. It was observed that there was a geographic difference between the relative condensate yield at a given maturity. Wells in Guernsey, Noble and Washington Counties have a higher condensate yield than wells to the north of this area in Harrison, Carroll and Columbiana Counties. Therefore, one function from maturity to condensate yield for the entire eastern Ohio area was not sufficient. One function with relatively lower condensate yield was used for the northern area and another was used for the southern area. This technique has proven successful in other North American unconventional plays. The Utica-Pt. Pleasant unconventional play produces gas and condensate in eastern Ohio and western Pennsylvania. Condensate yield is important to the commercial success of the play, so there is in interest in improving the pre-drill prediction of this parameter. In general, measured and modeled maturity can be used as a predictive tool to distinguish areas prospective for oil, wet gas and dry gas for unconventional plays. Usually oil is found in the 0.6-1.1 Ro range, wet gas from 1.1-1.7 and dry gas over 1.7. In this case we attempt to predict condensate yield rather than just wet gas based on a range of modeled maturity. A 3D maturity model of the Utica-Point Pleasant Basin was constructed in order to predict maturity (vitrinite reflectance equivalence or VRE) for multiple stratigraphic horizons. The horizons modeled were the Berea, Marcellus, Top Ordovician, Utica, Top Knox, Base Knox and Basement. In addition to structural horizons a map estimating late Paleozoic erosion was constructed. An uncorrected temperature gradient map from bottom hole temperatures from nearly 1500 wells was also made. This map was adjusted to correlate the Utica-Point Pleasant modeled maturity to the rock maturity for this interval. Utica-Point Pleasant model maturity to rock maturity correlation coefficient was about .50. This calibrated temperature gradient map was then used to model the other six horizons. Condensate yield was calculated from Utica-Point Pleasant production data for 256 wells provided by the Ohio Department of Natural Resources. These condensate yields were correlated to Utica-Pt. Pleasant modeled maturity and a good correlation (R2 = .76) was found between these data sets. The Utica-Point Pleasant modeled maturity map was then transformed to a condensate yield map by means of the equation. It was observed that there was a geographic difference between the relative condensate yield at a given maturity. Wells in Guernsey, Noble and Washington Counties have a higher condensate yield than wells to the north of this area in Harrison, Carroll and Columbiana Counties. Therefore, one function from maturity to condensate yield for the entire eastern Ohio area was not sufficient. One function with relatively lower condensate yield was used for the northern area and another was used for the southern area. This technique has proven successful in other North American unconventional plays. Panel_15594 Panel_15594 8:30 AM 5:00 PM

Panel_14500 Panel_14500 8:30 AM 5:00 PM

In order to better understand gas and water interaction with organic matter (natural coal) of different maturity we developed a molecular concept with experimental and literature support for sorption of CH4, CO2 and H2O on organic material over a broad range of thermal maturity (0.5–3.3% vitrinite reflectance). We present a conceptual model to explain CO2 and CH4 sorption in the presence of water on coal with varying coal maturity (from subbituminous to anthracite). Adsorption experiments have been performed on coals of different maturity at temperatures between 303 and 350 K, pressures up to 20 MPa and under dry and moisture-equilibrated conditions. With increasing coal maturity we find for both gases a linear sorption capacity trend for the moist and a more parabolic trend for the dry coal samples (Busch and Gensterblum, 2011). Based on the differences in CH4 and CO2 sorption capacity on coals of different maturity as a function of moisture content we infer that oxygen-containing functional groups represent the primary sorption sites for which CO2 or CH4 compete with water molecules. The competitive interaction turns out to be a volumetric displacement independent of the gas type. A pore blocking mechanism could not be confirmed. Adsorbed molecules on anthracite are mobile within the adsorbed phase at low surface coverage. Additionally, restrictions in translational and vibrational movements of the sorbed gas molecules induced by adsorbed water molecules are observed. Therefore we conclude that sorbed molecules are more localised when water is present in the adsorbed phase, whereas at high surface coverage, the thermodynamic properties of adsorbed molecules are dominated by adsorbate–adsorbate interactions. In order to better understand gas and water interaction with organic matter (natural coal) of different maturity we developed a molecular concept with experimental and literature support for sorption of CH₄, CO₂ and H₂O on organic material over a broad range of thermal maturity (0.5–3.3% vitrinite reflectance). We present a conceptual model to explain CO₂ and CH₄ sorption in the presence of water on coal with varying coal maturity (from subbituminous to anthracite). Adsorption experiments have been performed on coals of different maturity at temperatures between 303 and 350 K, pressures up to 20 MPa and under dry and moisture-equilibrated conditions. With increasing coal maturity we find for both gases a linear sorption capacity trend for the moist and a more parabolic trend for the dry coal samples (Busch and Gensterblum, 2011). Based on the differences in CH₄ and CO₂ sorption capacity on coals of different maturity as a function of moisture content we infer that oxygen-containing functional groups represent the primary sorption sites for which CO₂ or CH₄ compete with water molecules. The competitive interaction turns out to be a volumetric displacement independent of the gas type. A pore blocking mechanism could not be confirmed. Adsorbed molecules on anthracite are mobile within the adsorbed phase at low surface coverage. Additionally, restrictions in translational and vibrational movements of the sorbed gas molecules induced by adsorbed water molecules are observed. Therefore we conclude that sorbed molecules are more localised when water is present in the adsorbed phase, whereas at high surface coverage, the thermodynamic properties of adsorbed molecules are dominated by adsorbate–adsorbate interactions. Panel_15636 Panel_15636 8:30 AM 5:00 PM

For the oil shales in Northeast China, the transient temperature field of in situ conversion was calculated through numerical simulation. And the kinetics parameters were obtained from Rock-Eval pyrolysis experiments. Hydrocarbon generation rates of oil shale at various times and temperatures were calculated from kinetics parameters and temperature field. Under in situ retorting, the pyrolysis temperature of oil shale ranged from 200 to 280 degrees Celsius, i.e. the oil shale needs to be heated about 8-10 years. For the oil shales in Northeast China, the transient temperature field of in situ conversion was calculated through numerical simulation. And the kinetics parameters were obtained from Rock-Eval pyrolysis experiments. Hydrocarbon generation rates of oil shale at various times and temperatures were calculated from kinetics parameters and temperature field. Under in situ retorting, the pyrolysis temperature of oil shale ranged from 200 to 280 degrees Celsius, i.e. the oil shale needs to be heated about 8-10 years. Panel_15639 Panel_15639 8:30 AM 5:00 PM

This study will elucidate geochemical variations in the development of Lake Uinta (Eocene Green River Formation – GRF), in both marginal and basin center environments in Colorado through elemental geochemistry at Douglas Pass, and later on cores at the U. S. Geological Survey Core Research Center. Major and trace element abundances can be compared to existing geochemical and mineralogic data to define the salinity, alkalinity, silica activity, redox potential and trace element character of sediments of the GRF. X-ray fluorescence analyses were conducted on excavated outcrop surfaces and samples removed from outcrop with a Niton (XL3 Analyzer) handheld spectrometer over part of a previously described stratigraphic section in Douglas Pass. Outcrop surfaces present challenges to effective measurement, particularly due to the potential for visually fresh surfaces to be contaminated by recent precipitation (e. g. gypsum) from ground water, due to the relatively small depth of penetration. Results of our first season analysis show the tool to be an effective means of rapid dense sampling and give an enhanced view of the chemical variability of marginal sedimentation. Repeatability was confirmed by regular measurements of a single sample, especially before and after battery changeout. Even where potential contamination was identified after analysis was complete, element ratios provide a means to understand chemical variation. Major element chemistry identifies much of the section as mixed clastic and carbonate siltstone/mudstone, shale, with interbedded sandstone and carbonate beds that are recognized markers of stratigraphic boundaries. Si/Al ratio faithfully reflects sand/clay content in mixed beds, and is especially distinct in thick sandstone near the top of the measured interval. Ca/Mg ratio is relatively constant, with high Ca/Mg spikes, suggesting calcite rich intervals in a background of constant calcite/dolomite. Fe concentration declines at the top of the interval, primarily due its low abundance in the sandstones that mark base of the R4 zone. Fe and Al are weakly correlated, suggesting iron arrives with clastic components. Zr/Nb effectively identifies sandier intervals in a section notable for the difficulty of hand specimen grain size estimation. V/Cr ratio ranges from 1.5-3, in good agreement with previous results, indicating oxic to dysoxic conditions. This study will elucidate geochemical variations in the development of Lake Uinta (Eocene Green River Formation – GRF), in both marginal and basin center environments in Colorado through elemental geochemistry at Douglas Pass, and later on cores at the U. S. Geological Survey Core Research Center. Major and trace element abundances can be compared to existing geochemical and mineralogic data to define the salinity, alkalinity, silica activity, redox potential and trace element character of sediments of the GRF. X-ray fluorescence analyses were conducted on excavated outcrop surfaces and samples removed from outcrop with a Niton (XL3 Analyzer) handheld spectrometer over part of a previously described stratigraphic section in Douglas Pass. Outcrop surfaces present challenges to effective measurement, particularly due to the potential for visually fresh surfaces to be contaminated by recent precipitation (e. g. gypsum) from ground water, due to the relatively small depth of penetration. Results of our first season analysis show the tool to be an effective means of rapid dense sampling and give an enhanced view of the chemical variability of marginal sedimentation. Repeatability was confirmed by regular measurements of a single sample, especially before and after battery changeout. Even where potential contamination was identified after analysis was complete, element ratios provide a means to understand chemical variation. Major element chemistry identifies much of the section as mixed clastic and carbonate siltstone/mudstone, shale, with interbedded sandstone and carbonate beds that are recognized markers of stratigraphic boundaries. Si/Al ratio faithfully reflects sand/clay content in mixed beds, and is especially distinct in thick sandstone near the top of the measured interval. Ca/Mg ratio is relatively constant, with high Ca/Mg spikes, suggesting calcite rich intervals in a background of constant calcite/dolomite. Fe concentration declines at the top of the interval, primarily due its low abundance in the sandstones that mark base of the R4 zone. Fe and Al are weakly correlated, suggesting iron arrives with clastic components. Zr/Nb effectively identifies sandier intervals in a section notable for the difficulty of hand specimen grain size estimation. V/Cr ratio ranges from 1.5-3, in good agreement with previous results, indicating oxic to dysoxic conditions. Panel_15638 Panel_15638 8:30 AM 5:00 PM

The interaction and the coupling of slip-flow, a fluid dynamic phenomenon, and the cleat volume compressibility which is a poroelastic phenomenon has been investigated on two samples from the Taroom coal measure, Surat Basin, Queensland Australia (Gensterblum et al., 2014). Measurements were performed using inert (helium and argon) and sorbing gases (nitrogen, methane and carbon dioxide) at controlled effective stress. Apparent permeability coefficients decreased in the order helium >> argon = nitrogen > methane > carbon dioxide. Even after slip-flow correction different permeability coefficients were obtained for the same sample and identical stress conditions when different gases were used as permeating fluids. These observations are inconsistent with the concept of “intrinsic permeability” which, as a material property, should be independent of the permeating fluid. Obviously the sequence of the “intrinsic” permeability is identical to the sequence of increasing non-ideality. Therefore, it should be considered that the classical Darcy equation, which is derived using the ideal gas law has a reduced validity for non-ideal gases like N2, CH4 and especially CO2. The cleat volume compressibility cf was evaluated using the “matchstick approach” (Robertson and Christiansen, 2008). The cleat volume compressibility coefficients cf are almost identical for the two samples taken from the same well. However, for one sample a strong dependence of the cf with the mean pore pressure was observed. This is attributed to a strong slip-flow effect caused by a narrow cleat system as compared to the sister sample. The cleat volume compressibility coefficient cf is almost the same for non-sorbing and sorbing gases. The obvious strong coupling of slip-flow and poro-elastic properties is due to the generally more compressibility of coals in comparison to sandstones. The interaction and the coupling of slip-flow, a fluid dynamic phenomenon, and the cleat volume compressibility which is a poroelastic phenomenon has been investigated on two samples from the Taroom coal measure, Surat Basin, Queensland Australia (Gensterblum et al., 2014). Measurements were performed using inert (helium and argon) and sorbing gases (nitrogen, methane and carbon dioxide) at controlled effective stress. Apparent permeability coefficients decreased in the order helium >> argon = nitrogen > methane > carbon dioxide. Even after slip-flow correction different permeability coefficients were obtained for the same sample and identical stress conditions when different gases were used as permeating fluids. These observations are inconsistent with the concept of “intrinsic permeability” which, as a material property, should be independent of the permeating fluid. Obviously the sequence of the “intrinsic” permeability is identical to the sequence of increasing non-ideality. Therefore, it should be considered that the classical Darcy equation, which is derived using the ideal gas law has a reduced validity for non-ideal gases like N2, CH₄ and especially CO₂. The cleat volume compressibility cf was evaluated using the “matchstick approach” (Robertson and Christiansen, 2008). The cleat volume compressibility coefficients cf are almost identical for the two samples taken from the same well. However, for one sample a strong dependence of the cf with the mean pore pressure was observed. This is attributed to a strong slip-flow effect caused by a narrow cleat system as compared to the sister sample. The cleat volume compressibility coefficient cf is almost the same for non-sorbing and sorbing gases. The obvious strong coupling of slip-flow and poro-elastic properties is due to the generally more compressibility of coals in comparison to sandstones. Panel_15637 Panel_15637 8:30 AM 5:00 PM

Egypt is facing an excruciating energy crisis. One of the solutions to such a crisis is by developing the tremendous oil shale resources that exist in the Quseir - Safaga district in the Eastern Desert and is expected to contain around 12 billion barrels of oil and 24 trillion standard cubic feet of gas. This resource could be produced either by ex-situ or in-situ techniques; the latter being the subject of this paper. There are many problems facing the application of in-situ heating in the Quseir – Safaga oil shale resources. First of all, all the current world projects to produce shale oil by in situ heating methods are in test and pilot stages; none have demonstrated large scale commercial production. An additional problem is that not much data is available about the geology of such resources. To overcome such problems, and based on the scarce available data, a simple screening study is carried out in order to evaluate the applicability of the various methods of in-situ production of oil and gas. The most promising techniques that need deeper investigations are found to be Geothermic Fuel Cells (GFC), Radio Frequency (RF) heating, and EcoShale™ In-Capsule Technology. However, many problems are associated with their application. Solution of the many questions related to such problems could most likely come about by means of carefully monitored pilot-scale experiments in the field. However, performing such experiments in the deep formation would be highly costly. To help solve these questions, the research has modified upon existing techniques. The new techniques, namely Solid Oxide Fuel Cell (SOFC) In-Capsule and Radio Frequency (RF) In-Capsule techniques, can be seen as combinations of the previously selected techniques but with modifications that could increase the process efficiency. Compared to other heating techniques, these techniques might save much money, help solve the problems and much facilitate the second generation field scale pilot in-situ experiments. Egypt is facing an excruciating energy crisis. One of the solutions to such a crisis is by developing the tremendous oil shale resources that exist in the Quseir - Safaga district in the Eastern Desert and is expected to contain around 12 billion barrels of oil and 24 trillion standard cubic feet of gas. This resource could be produced either by ex-situ or in-situ techniques; the latter being the subject of this paper. There are many problems facing the application of in-situ heating in the Quseir – Safaga oil shale resources. First of all, all the current world projects to produce shale oil by in situ heating methods are in test and pilot stages; none have demonstrated large scale commercial production. An additional problem is that not much data is available about the geology of such resources. To overcome such problems, and based on the scarce available data, a simple screening study is carried out in order to evaluate the applicability of the various methods of in-situ production of oil and gas. The most promising techniques that need deeper investigations are found to be Geothermic Fuel Cells (GFC), Radio Frequency (RF) heating, and EcoShale™ In-Capsule Technology. However, many problems are associated with their application. Solution of the many questions related to such problems could most likely come about by means of carefully monitored pilot-scale experiments in the field. However, performing such experiments in the deep formation would be highly costly. To help solve these questions, the research has modified upon existing techniques. The new techniques, namely Solid Oxide Fuel Cell (SOFC) In-Capsule and Radio Frequency (RF) In-Capsule techniques, can be seen as combinations of the previously selected techniques but with modifications that could increase the process efficiency. Compared to other heating techniques, these techniques might save much money, help solve the problems and much facilitate the second generation field scale pilot in-situ experiments. Panel_15641 Panel_15641 8:30 AM 5:00 PM

Statistical data show that gas outburst has a very close relationship with tectonic deformation because it often occurs in shear zones where deformed coals are widely developed. The amounts of outburst gas are usually much higher than the maximum adsorptions that are supposed to be in coal, which means that excess coalbed methane (CBM) may exist in deformed coals. Therefore, a correct understanding of the occurrence of excess gas may lead to an important breakthrough in explaining the gas outburst mechanism and gas occurrence theory. Deformed coals collected from Huainan-Huaibei and Qinshui Basin of China have been studied through a series of experiments over the past few years in our research group. Sub-high-temperature and sub-high-pressure deformation experiments on middle and high rank coals were designed to explore the mechanisms of gas generation during coal deformation. CH4 and CO were collected from middle and high rank coals, respectively. Preliminary results of elemental analysis, FTIR and quantum chemistry methods etc. show that ductile deformation could increase the structure defects of basic structural units. Oxygen-containing groups or ether bond are degraded by less than 10% strain energy, and generate gas micromolecule. As a result, lower rank coals that contain many alkane chains which have low bond energy could easily degrade under tectonic deformation. This process could generate large quantities of gas which will result in gas outburst when aggregated to a certain amounts. Therefore, coal deformation can occur under the tectonic stress, leading to the production of gas, which may be one of the sources of the excess CBM. The discussion of the conventional physical ideas on coal-absorbed gas is extended in these studies, according to the phenomenon of excess CBM, the gas molecular has a significant chance of existing in chemical bonds of low bond energy in coal structure. Furthermore, the surface area and volume of nanopores in strongly deformed coal are greater than that in primary structure coal, which could provide more spaces for gas accumulation. Keywords: Coal; Tectonic deformation; Macromolecular structure; Excess CBM; Gas generation Statistical data show that gas outburst has a very close relationship with tectonic deformation because it often occurs in shear zones where deformed coals are widely developed. The amounts of outburst gas are usually much higher than the maximum adsorptions that are supposed to be in coal, which means that excess coalbed methane (CBM) may exist in deformed coals. Therefore, a correct understanding of the occurrence of excess gas may lead to an important breakthrough in explaining the gas outburst mechanism and gas occurrence theory. Deformed coals collected from Huainan-Huaibei and Qinshui Basin of China have been studied through a series of experiments over the past few years in our research group. Sub-high-temperature and sub-high-pressure deformation experiments on middle and high rank coals were designed to explore the mechanisms of gas generation during coal deformation. CH₄ and CO were collected from middle and high rank coals, respectively. Preliminary results of elemental analysis, FTIR and quantum chemistry methods etc. show that ductile deformation could increase the structure defects of basic structural units. Oxygen-containing groups or ether bond are degraded by less than 10% strain energy, and generate gas micromolecule. As a result, lower rank coals that contain many alkane chains which have low bond energy could easily degrade under tectonic deformation. This process could generate large quantities of gas which will result in gas outburst when aggregated to a certain amounts. Therefore, coal deformation can occur under the tectonic stress, leading to the production of gas, which may be one of the sources of the excess CBM. The discussion of the conventional physical ideas on coal-absorbed gas is extended in these studies, according to the phenomenon of excess CBM, the gas molecular has a significant chance of existing in chemical bonds of low bond energy in coal structure. Furthermore, the surface area and volume of nanopores in strongly deformed coal are greater than that in primary structure coal, which could provide more spaces for gas accumulation. Keywords: Coal; Tectonic deformation; Macromolecular structure; Excess CBM; Gas generation Panel_15635 Panel_15635 8:30 AM 5:00 PM