Full waveform inversion in the time lapse mode applied to CO₂storage at Sleipner

Carbon capture and storage is a viable greenhouse gas mitigation technology and the Sleipner CO 2 sequestration site in the North Sea is an excellent example. Storage of CO 2 at the Sleipner site requires monitoring over large areas, which can successfully be accomplished with time lapse seismic imaging. One of the main goals of CO 2 storage monitoring is to be able to estimate the volume of the stored CO 2 in the reservoir. This requires a parametrization of the subsurface as exact as possible. Here we use elastic 2D time‐domain full waveform inversion in a time lapse manner to obtain a P‐wave velocity constrain directly in the depth domain for a base line survey in 1994 and two post‐injection surveys in 1999 and 2006. By relating velocity change to free CO 2 saturation, using a rock physics model, we find that at the considered location the aquifer may have been fully saturated in some places in 1999 and 2006.