Time-lapse Analysis of Sparse 3D Seismic Data from the CO2 Storage Pilot Site at Ketzin, Germany

In April 2004, a research pilot project in the German town of Ketzin started as the first onshore CO2 storage project in Europe. Injection started in June 2008 and until the latest repeat survey in February 2011 around 45 kilotons of CO2 had been injected into a saline aquifer at approximately 630 m depth. Different seismic methods, such as time-lapse Vertical Seismic Profiling, Crosswell, Moving Source Profiling and surface seismics have been employed to detect and monitor changes in the reservoir. We present here time-lapse results from sparse pseudo-3D seismic surveying with a radial distribution of acquisition profiles directed towards the approximate location of the injection well, which were acquired to link downhole surveys with full 3D surface seismic surveys. The results are consistent with the 3D seismic time-lapse studies over the injection site and show that the sparse 3D geometry can be used to qualitatively map the CO2 in the reservoir at a significantly lower effort than the full 3D surveying. The last repeat survey indicates preferential migration of the CO2 to the west. There are no indications of migration into the caprock on either of the repeat surveys. The same observation was obtained from the full 3D dataset.