Geophysical monitoring of CO2 at the Ketzin storage site - The Results of the second 3D repeat seismic survey

Abstract

Various geophysical methods applied at the Ketzin storage site have successfully imaged migration of the injected CO2 within the target reservoir zone of the ~ 650-680 m deep saline aquifer. Results from the first 3D repeat seismic survey conducted in 2009, after about 15 months of injection (~22,000 t), showed that the CO2 plume was concentrated around the injection well with a lateral extent of approximately 300-400 m and a thickness of about 5–20 m. The plume, however, was not radially symmetric, but had a rather westerly trending tendency, revealing the heterogeneous nature of the reservoir. A second 3D repeat seismic survey was acquired in the Summer/Fall of 2012, when ~ 61,000 tons of CO2 had been injected. Preliminary results show further growth and migration of the anomaly which has been interpreted to be induced by the CO2 injection. It is similar in shape to the one observed at the time of the first repeat survey, but larger by approximately 100-200 m and much stronger with the highest amplitudes nearly centered at the injection well. There is still a pronounced westward propagating tendency. The new seismic data show no indication of upward migration into the caprock.