An Assessment of Undiscovered Oil and Gas Resources in Clastic Facies of the Lower Cretaceous Sligo Formation, Eastern U.S. Gulf of Mexico Coastal Plain

Colin A. Doolan and Alexander W. Karlsen
U.S. Geological Survey, 12201 Sunrise Valley Dr., Reston, Virginia 20192

As part of a basin-wide study, the U.S. Geological Survey (USGS) has completed an assessment of the technically recoverable undiscovered oil and gas resources in the Lower Cretaceous Sligo Sandstone Gas and Oil Assessment Unit (AU) of the U.S. Gulf of Mexico Coastal Plain and state waters. This AU consists of the clastic facies of the Sligo Formation in the eastern Gulf Coastal Plain (the states of Mississippi, Alabama, and Florida) and is bound stratigraphically by the underlying Lower Cretaceous Hosston Formation and the overlying Lower Cretaceous Pine Island Shale (where present) and Rodessa Formation.

To date, thirteen gas fields and thirteen oil fields have produced from within the AU. This production is exclusive to the flanks of salt anticlines and salt ridges within the Mississippi Interior Salt Basin and associated normal fault traps. Therefore, we suspect undiscovered reservoirs will primarily be around similar features that are unexplored or underexplored to date. Based on existing well log, seismic, and production data, the undiscovered resources within the AU are most likely natural gas accumulations toward the center of the Mississippi Interior Salt Basin.

The possibility exists for the discovery of petroleum accumulations updip from the Mississippi Interior Salt Basin. These updip reservoirs would likely be small accumulations trapped stratigraphically or by normal faults. However, undiscovered resource potential in this area remains low due to the absence of a continuous sealing formation. Seismic investigations involving a network of high resolution 2D surveys would be necessary to delineate specific areas of potential hydrocarbon accumulation in the updip area of the AU.

AAPG Search and Discovery Article #90158©2012 GCAGS and GC-SEPM 6nd Annual Convention, Austin, Texas, 21-24 October 2012