A geophysical characterization of stratigraphy in the Eastern Black Warrior Basin underlying Gorgas Power Generation Plant, Walker County, Alabama

The Black Warrior Basin is a triangular shaped foreland basin located in the southeastern United States between the Appalachian and Ouachita fold and thrust belts. The basin has the potential to provide geologic carbon sinks into multiple stacked saline reservoirs over a large area. CO_2 storage potential of saline aquifers and oil and gas reservoirs in the Black Warrior Basin has yet to be fully assessed. This study evaluates saline reservoirs on the eastern edge of the basin underlying William C. Gorgas Power Plant (Plant Gorgas), Walker County, Alabama. Key reservoirs include the Pennsylvanian Boyles Sandstone, the Mississippian Hartselle Sandstone and Tuscumbia Limestone, and the Ordovician Stones River Group. Data include two post-stack time-migrated seismic reflection profiles, geophysical logs collected in a 1498 m (4915 ft) stratigraphic test well, and a zero-offset vertical seismic profile (ZVSP). Interpretations of key seismic reflectors in the Black Warrior Basin are presented based on a synthetic seismogram, check-shots, a zero-offset VSP, and a well-constrained well-seismic tie. Units in the velocity model are based on lithologic boundaries interpreted as seismic horizons and well tops. An investigation of geologic structures and the lateral extent of saline aquifers in the area surrounding Plant Gorgas is based on depth converted seismic data. Volumetric calculations for the Boyles and Hartselle sandstones, and the Tuscumbia and Stones River Group limestones were calculated to demonstrate the potential to store substantial amounts of carbon dioxide in the Black Warrior Basin. The volumetric estimations that are listed below show the effects of injecting 10% of Plant Gorgas's emissions (0.75 Megatons of CO_2 /year) over a thirty-year period. The Lower Boyles Sandstone CO_2 plume would extend to a radius of 3.6 km (2.25 miles) ± 0.22 km (0.14 miles) around the borehole; 5.2 km (3.23 miles) ± 0.35 km (0.22 miles) in the Hartselle Sandstone; 4.7 km (2.92 miles) ± 0.07 km (0.04 miles) in the Tuscumbia Limestone; and 7.2 km (4.47 miles) ± 0.065 km (0.04 miles) in the Stones River Formation. (Published By University of Alabama Libraries