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Preliminary delineation of geologic trends and processes controlling petroleum accumulation in the Upper Jurassic of southwestern Alabama

Book ·
OSTI ID:6223768

The recent Upper Jurassic petroleum discoveries (Hatter's Pond and Chunchula Fields) in Mobile County indicate that southwestern Alabama is an important area for petroleum exploration. The geologic history of the Upper Jurassic (Smackover and Norphlet Formations) appears to be ideal for petroleum generation, migration, and entrapment. The petroleum trap in Chunchula Field is an anticline, probably resulting from salt tectonics, associated with favorable stratigraphy. The petroleum trapping mechanism in Hatter's Pond Field is a combination of extensional faulting of the Jackson fault, salt movement, and favorable stratigraphy. Additional anticlinal structures are present in southwestern Alabama to the northeast and east of the producing fields. Smackover medium-grained dolomite and Norphlet eolian sandstone are the petroleum reservoirs. The Smackover grainstones probably accumulated on shoal areas on a shallow shelf or near the shelf margin. The Smackover medium-grained dolomite grades into fine-grained dolomite to the east and northeast of the fields. The apparently more diagenetically altered carbonate reservoir in Chunchula Field is probably a result of leaching, cementation, and dolomitization of paleohighs during the time of Smackover deposition or post-depositionally. Smackover fine-grained carbonates are speculated to be the petroleum source.

OSTI ID:
6223768
Report Number(s):
NP-23725
Country of Publication:
United States
Language:
English