Hydrocarbon Potential of the Ferry Lake Anhydrite, Eastern Gulf of Mexico, Southern Mississippi Province
Faith O. Amadi
The University of Mississippi, Department of Geology and Geological Engineering
The Lower Cretaceous Ferry Lake Anhydrite in the Southern Mississippi Province is composed of approximately 76 m (250 ft) of alternating carbonate and evarporite beds that have been interpreted as being deposited within a stratopycline free-flow exchange basin, which functioned as a broad lagoon behind the Staurt City reef. Evaluation of cores from Waveland field, located in Hancock County, Mississippi, and several cross sections across the Southern Mississippi Province indicate interfingering between alternating carbonate and anhydrite facies. Farther south, thinning of anhydrite beds and interfingering thickening carbonate beds provides potential for stratigraphic hydrocarbon traps. Although the Ferry Lake Anhydrite in this area is characterized by minor fracture porosity, low overall porosities (approximately 8%) and low permeabilities (approximately 20 md). There is proven hydrocarbon production from similar Ferry Lake facies west of the Mississippi River (Fairway field in Texas and Caddo-Pine Island field in Louisiana).
Samples for geochemical analysis were selected from two carbonate beds within the unit. The first sample is at the depth of 4,084 m (13,398 ft) with 0.53% total organic carbon, vitrinite reflectance of 0.71%, and Tmax of 437 0C. A second sample from 4106 meters (13471 feet) has 1.0% total organic carbon, vitrinite reflectance of 0.72%, and Tmax of 438 0C. These results indicate that Ferry Lake carbonates in this area are fair to good source rocks that are thermally mature, placing these units within the oil-generation window.
AAPG Search and Discovery Article #90070 © 2007 AAPG Foundation Grants in Aid