Feasibility Study of Time-Lapse Monitoring of Foam-Assisted EOR Using RTM

Among many methods to achieve Enhanced Oil Recovery (EOR), we focus on foam-assisted EOR because of the high performance in sweep by a foam zone to avoid fingering or tonguing in reservoir. The mechanisms of foam-assisted EOR have been revealed by many studies both in microscopic and macroscopic ways. However, the monitoring method to explore the advancement of foam front in the subsurface and property change in reservoir caused by injected fluids and surfactants has not been fully established yet.

We hypothesized that seismic methods could be used for the monitoring of foam-assisted EOR. To validate this hypothesis, we conducted numerical simulation of time-lapse seismic monitoring by finite-difference method. We made numerical models assuming the practice of foam-assisted EOR utilizing Marmousi2 model and generated synthetic data sets from the models. Then we applied RTM to the obtained data sets.

Our numerical experiments indicated that we could capture the advancement of sweeping foam front using RTM even if the reservoir exists in complicated structure and that we could gain some information on variation of properties of reservoir by analyzing obtained RTM results.