Seismic Plume Evolution in a Heterogeneous Sandstone Reservoir: Role and Impact of Patchy CO2 Saturation.

Abstract

In this study we combine reservoir simulation with 2D synthetic reflection seismic time-lapse data to assess the ability of seismic methods to image plume growth and evolution within a heterogeneous saline reservoir. In order to capture the range of responses which could be encountered, two end-member fluid distribution models were used: uniform saturation model and patchy saturation model. Patchy saturation corresponds to short time-scale while uniform saturation is the equilibrium state achieved after sufficient time has elapsed. These end-member models give rise to different velocity distributions in the reservoir. The change in velocity is shown to be directly related to the concentration of the CO2 in the reservoir, which not only has great implications for CO2 detectability, but also for quantifying the volume of injected CO2 within the reservoir.