Comparing the Depositional Environment of the Upper Smackover Formation in Southwestern Clarke County, Mississippi and Brooklyn/Little Cedar Creek Field, Alabam

This research evaluated the depositional settings of the upper Smackover Formation in southwestern Clarke County (SCC), Mississippi and compared its facies to those of the Brooklyn and Little Cedar Creek Fields (BF/LCC) in Conecuh and Escambia Counties, Alabama. The Smackover Formation has been a prolific oil producing formation in the Gulf of Mexico since its discovery in Union County, Arkansas in 1937. The discovery of the LCC in 1994 and the BF in 2007 has generated additional interest in the Smackover. The BF/ LCC occur near the updip limit of the Upper Jurassic (Oxfordian) Smackover Formation. These fields produce from oolitic/ oolmoldic stratigraphically trapped reservoirs in the upper Smackover Formation. In SCC, the Smackover extends farther updip than in the BF/LCC. SCC also has several small oil fields that have produced from the Smackover Formation since 1976. This research used resistivity well logs and core analyses of SCC fields and selected four fields with the most oolites and therefore, the highest potential for similarity to production in the BF/LCC. The resistivity logs and core analyses of these four fields were used to construct structure contour maps and cross-sections for each field, illustrating the Smackover facies in the region. Higher resolution resistivity logs and core analyses from the BF/LCC were also used to construct cross sections of that area. Lithofacies and logfacies were defined for the research and used to compare the BF/LCC and SCC. Interpretation of the cross sections and maps showed that the BF/LCC and SCC have similar depositional settings and also similar lithofacies/depositional sequence. The difference between the study areas are: a lack of mudstones lithofacies in the BF/LCC; differences in thickness of the upper Smackover and; differences in logfacies. The BF/LCC and SCC have substantial similarities in their depositional environment and sequence with the East Nancy field in SCC showing the most similarities to the BF/LCC.