Monitoring of CO_2 injected at Sleipner using time-lapse seismic data

摘要

Since October 1996, Statoil and its Sleipner partners have injected CO_2 into a saline aquifer, the Utsira Sand, at a depth of approximately 1000 m. The aquifer has a thickness of more than 200 m near the injection site and is sealed by thick shales. A multi-institutional research project SACS (Saline Aquifer CO_2 Storage) was formed to predict and monitor the migration of the injected CO_2. To this end two time-lapse seismic surveys over the injection area have been acquired, one in October 1999, after 2.35 million tonnes of CO_2 had been injected, and the second in October 2001, after approximately 4.26 million tonnes of CO_2 had been injected. Comparison with the baseline seismic survey of 1994 prior to injection provides insights into the migration of the CO_2. In this paper the results of the seismic interpretation will be shown, supported by synthetic seismic modelling and reservoir flow simulation of the migrating CO_2 at the two different time-steps.