Print this pageAbstract: Deposition, Facies Patterns, and Hydrocarbon Potential of Bangor Limestone (Mississippian), Northern Black Warrior Basin, Alabama and Mississippi
The Bangor Limestone was deposited as a carbonate-shelf, ramp-and-basin sequence on the northeast flank of the Warrior basin. Progradation southwestward was episodic and resulted in several cyclic units which grade upward from deeper water muddy facies into grainy-shoal facies. Shoal-facies regression eventually expanded the shelf more than 14 mi (22 km) basinward.
The Bangor can be divided into three members which are mappable throughout the shelf and ramp. Each member contains a shelf-blanketing, grain-support facies rich in crinoids, bryozoans, and oolites. Widely scattered patches of porous reservoir-quality limestone are present in this shallow-water suite; however, there are no indications of broad porosity pockets which might serve as large stratigraphic traps on the shelf.
Known gas accumulations on the Bangor shelf, i.e., Whitehouse and Falls City fields, appear to be low-relief closures with small reserves. Future discoveries are anticipated to be analogous to these. Small potential reserves and probable inability seismically to detect the low-relief structures make the shelf an unattractive objective. The Bangor ramp may offer better hydrocarbon potential. One speculative ramp model suggests the possibility of bryozoan-crinoidal mounding. Suggested mound-trap closure could reach 100 to 150 ft (30 to 45 m). If such mounds were densely spaced or areally large, economic hydrocarbon reserves could be present.
AAPG Search and Discovery Article #90972©1976 AAPG-SEPM Annual Convention and Exhibition, New Orleans, LA