GEOPHYSICAL CHARACTERIZATION OF THE SOUTH GEORGIA RIFT BASIN FOR SUPERCRITICAL CO2 STORAGE: A PRELIMINARY ASSESSMENT
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.