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Free keywords:
CO2 sequestration;
Ketzin pilot site;
Seismic monitoring;
3D time-lapse (4D);
Abstract:
tTo date, 3D time-lapse seismic monitoring at the Ketzin CO2storage pilot site comprised a baseline surveyconducted in 2005 and two repeat surveys conducted in 2009 and 2012. At the time of the first repeatsurvey (22–25 kt of CO2), the CO2plume was found to be concentrated around the injection well witha maximum lateral extent of approximately 300–400 m and a thickness of 5–20 m. Data from the 2012survey (61 kt of CO2), show further growth and migration of the amplitude anomaly interpreted to beinduced by the CO2injection. The anomaly is similar in shape to that obtained from the 2009 survey, butsignificantly stronger and larger by ∼150 m in the N–S direction and by ∼200 m in the E–W direction.In agreement with the 2009 survey, the new data show a westward propagation of the plume, a trendgoverned by the complex structure of the reservoir. No evidence of systematic changes in the seismic signaturewithin the overburden is observed. A quantitative assessment of the plume reveals a 15% discrepancywith the injected amount, which could be attributed to the ongoing dissolution processes. However, theestimated quantity also contains significant uncertainty.
