Paper No. 6
Presentation Time: 9:00 AM-6:30 PM


AKINTUNDE, Olusoga Martins, Earth and Ocean Sciences, University of South Carolina, 701 Sumter Street EWS 617, Columbia, SC 29208, KNAPP, Camelia C., Earth Sciences Research Institute, University of South Carolina, 701 Sumter Street EWS 617, Columbia, SC 29208 and KNAPP, James H., Earth and Ocean Sciences, University of South Carolina, 701 Sumter Street, Columbia, SC 29208,

The Triassic-Jurassic South Georgia Rift (SGR) basin, buried beneath Coastal Plain sediments of southern South Carolina, southeastern Georgia, western Florida, and southern Alabama, consists of an assemblage of continental rift deposits (popularly called red beds) and mafic igneous rocks (basalt flows and diabase sills). The red beds are capped by basalts and/or diabase sills, and constitute our target for supercritical CO2 storage as part of a Department of Energy funded project to study feasibility for long term sequestration. This geophysical characterization study is part of the growing response to the global need and urgency to mitigate rising concentrations of CO2 in the atmosphere, and by extension prevent its negative impacts on the environment.

The purpose of this research is to determine subsurface suitability for underground CO2 storage in terms of the local and regional distribution of porous and permeable target reservoirs. Also unlike shale-capped CO2 reservoirs, very little is known about the ability of basalts and diabase sills to act as viable seals for CO2 storage. Therefore, with this research, we implemented several methods including (1) lithologic analysis of cores and deep wells, (2) laboratory measurements on core samples, (3) analyses of XRD and X-ray CT data, and (4) interpretation of thin sections coupled with geophysical interpretation of well data. Our new results suggest that the SGR basin has confined porous rocks that may be capable of storing between 3.73 and 13.23 Gt of CO2. Reservoir thicknesses of about 420 m, and an average porosity of 14% were obtained. Besides, the basin manifests distinct porosity-permeability regimes that are influenced by the depositional environments. Also, the presence of low permeability red beds is a prominent occurrence within the basin. Analysis further show that the basalt flows and diabase sills possess characteristics favorable to caprock integrity.