Shuvajit Bhattacharya, Sujith Swaminadhan, Sahar Bakhshian

We study the feasibility of time-lapse surface seismic to detect and monitor CO2 plume movement over the time at the onshore Decatur CCS site, United States. We develop and test a workflow, integrating results from subsurface characterization, dynamic flow simulation, rock physics, time-lapse fluid saturation logs, and operational information to model surface seismic responses of the CO2-saturated Mt. Simon sandstone reservoir over the time. We perform fluid substitution modeling under both uniform and patchy mixing conditions. Results show that 4D surface seismic responses for the Mt. Simon reservoir are weak under the historic 1 Mt of CO2 injection, regardless of rock physics modeling constraints. Our modeled data under a hypothetical 10 Mt of CO2 injection improves the detectability of 4D surface seismic to detect CO2 plume boundary.