Revisiting Old Areas: Improving Correlations and Enhancing Exploration Success Using a Sequence-Stratigraphic Framework

Jim Puckette1,   Matt Huhnke2,   Kurtis Boucher3

¹Oklahoma State University,   ²RKI Exploration,   ³El Paso Exploration and Production

Discovering new reserves in mature petroleum provinces requires an understanding of the depositional and diagenetic processes that generated reservoir and sealing lithofacies. A key element to the logical interpretation of depositional processes is a sound stratigraphic framework based on geologic principles. Hot shales and coals were used to construct a chronostratigraphic framework for Pennsylvanian intervals where carbonate markers were undetectable. This framework was used to clarify stratigraphy, interpret depositional settings and assess the impact of subsidence rates on sediment dispersal.

This new stratigraphic framework relies on radioactive “hot shales” to identify maximum flooding and the cross-cutting relationship between sandstone bodies and hot shales to identify sequence boundaries. This framework can be extended into outer shelf and basinal settings where conditions were unsuitable for deposition of the thin carbonates that serve as conventional lithostratigraphic markers. Once the framework is in place, it is usually easier to interpret depositional systems, explain trapping mechanisms, and identify genetic units that could be partially or totally isolated from previously produced reservoirs. Interpreting the spatial distribution of sandstone bodies within a sequence-stratigraphic framework provides a mechanism to separate juxtaposed oil- and gas-bearing and water-bearing reservoirs. This framework is applied in the Arkoma and Anadarko basins to help explain the distribution pattern of thicker sandstone trends and enhance the search for targets for vertical and horizontal wells. Vintage areas in northeastern Oklahoma are reexamined using modern wireline log data that allows the delineation of interpreted lowstand incised valley trends and areas of potential oil and gas accumulations.

AAPG Search and Discover Article #90097 © 2009 Tulsa Geological Society, Tulsa, Oklahoma

 

 

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