This course is designed for geologists who interpret fine-grained rocks, explore for or develop conventional hydrocarbons, shale gas or oil shale. Mudstones contain the most detailed records of earth history and are sources, reservoirs, and seals of hydrocarbons, as well as serving as key elements in reservoir and aquifer models as baffles and barriers. Sequence stratigraphy provides an excellent framework within which to integrate the many scales of observations of physical, chemical and biological attributes necessary to understand these rocks across the spectrum of depositional settings. This workshop combines interactive lectures and exercises addressing the expression of depositional sequences in mudstones on seismic, well-log, core, and outcrop data. Examples include the New Albany Shale, Barnett Shale, Shublik Formation, Kimmeridge Formation, Kingak Formation, Hue Shale, Mowry Shale, and Monterey Formation.
Participants will practice recognizing and correlating significant stratigraphic packages through seismic stratigraphy, stacking pattern analysis of well-log, core and outcrop data, and facies analysis.
Although flooding surfaces and depositional-sequence boundaries may be subtly expressed in mudstones, they can be recognized through distinct changes observed in commonly available physical, chemical, and biological data. Beyond the chronostratigraphic utility of correlative conformity, abundant paleoenvironmental information is recorded in fine-grained strata - depositional sequences do not just fade away into obscurity in distal reaches, but have objective attributes that allow extension of stratigraphic frameworks and play-element predictions over very large areas.
Interactions of sediment supply and accommodation with pre-existing topography control the expression of depositional sequences. Marine environments tend to be mostly localized and abruptly changing. Lacustrine sequences vary according to lake-basin type, and range from very similar to shallow-marine siliciclastic sequences to very dissimilar.