Feasibility study of time-lapse seismic monitoring of CO₂ sequestration

Marie Macquet, Donald C. Lawton, Jessica M. Dongas, Jacky Barraza

Geological sequestration is one way to reduce our CO₂ emissions in the atmosphere. Background studies are made prior to the beginning of the injection to ensure the security of this method. In the CaMI.FRS project near Brooks, Alberta, numerous wells give us information about the lithology, the porosity, the permeability, the velocities (and many others parameters) of the medium. Beside these direct data, seismic studies were conducted in order to characterize the subsurface.

After this prior work is done, numerical simulations were done in order to characterize the feasibility of the time-lapse seismic monitoring. Indeed, once the injection begins, seismic survey will be made at regular intervals to monitor the CO₂ injection. Fluid simulations allow us to work on synthetic models, but yet are close to what we expect in the reality.

We use here Gassmann fluid substitution to obtain the elastic parameters (VP, VS and ) for different time of injection (1 year after the beginning of the injection and 1 year after the end of the injection), for a 300m depth CO₂ reservoir. In those models, synthetic data are generated then processed. This work give us a good approximation of the feasibility of a time-lapse seismic monitoring, considering the conditions of CaMI.FRS project.