Quantification of Injected CO2 Volumes from 4D Seismic Anomalies & Associated Uncertainties

Abstract

CO 2 capture and geological storage (CCS) is one solution among others to reduce greenhouse gas emission and mitigate climate change in a fossil fuel-dependent world. To be efficient, CCS technologies will have to be deployed at large scale, with the goal of storing Giga Tons of CO 2 . Several monitoring technologies are available today to ensure the safety of these storage operations by tracking the CO 2 plume in the reservoir to verify that the injected gas remains well contained and is not leaking out of the reservoir to shallower formations. Among the different techniques established to monitor CO 2 injection, 4D (time-lapse) seismic is one of the most accurate to determine the spatio-temporal evolution of the plume (as seen in the Sleipner and Snøhvit cases). 4D active seismic benefits from large amount of know-how from the oil and gas industry and, when justified by a feasibility study, is one of the techniques that is most frequently used for CCS monitoring. However, quantification of the injected CO 2 volumes directly from 4D anomalies is something that remains difficult, with uncertainties arising from several places including: