Geothermal and Geopressure Assessment with Implications for Carbon Dioxide Sequestration, Lower Tuscaloosa Formation, Louisiana

Timmon Drumm and Jeffrey A. Nunn
Department of Geology and Geophysics, Louisiana State University, E235 Howe-Russell Complex, Baton Rouge, Louisiana 70803

Proximity to near-term anthropogenic carbon dioxide sources and existing infrastructure make Louisiana a desirable location for carbon capture and storage. Spontaneous potential, gamma ray, and resistivity logs from 96 wells were used in a regional scale evaluation of the Massive Sand member of the lower Tuscaloosa Formation in Louisiana for carbon dioxide sequestration. Subsurface depths to the top of the Massive Sand member range from roughly 750 m to 6400 m (2460–21,000 ft) with a regional basinward dip. Gross sandstone isopach reveals substantial sandstone thicknesses with a general trend of thickening basinward. Reservoir temperatures, estimated from corrected bottom hole temperatures, range from 44°C to 196°C (111–353°F) with an average regional geothermal gradient of 0.029°C/m (1.6°F/100 ft). Reservoir pressures, determined from mud weight data, indicate a pressure range from 8 MPa (1160 psi) in north Louisiana to 71 MPa (10,300 psi) in the deepest locations. Under these conditions, carbon dioxide should be in a supercritical phase with densities of 200–750 kg/m³ (13–50 lbs/ft³). Regionally, the Massive Sand member varies from normally pressured in the north to geopressured in the south. However, locally thick sandstones, greater than 45 m (150 ft) located in Pointe Coupee, East Feliciana, East Baton Rouge, and Livingston parishes in central Louisiana appear to be normally pressured even though they are below the regional top of geopressure trend. Volumetric estimation suggests the area could sequester over 80 million metric tons (176 billion lbs) of carbon dioxide.

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