Impact of Top-reservoir Morphology on CO2 Sequestration

Models used for evaluating CO2 plume behaviour in the subsurface often employ simplified geological reservoir descriptions. Experiences from the petroleum industry show, however, that geological heterogeneities significantly influence fluid flow. The present study addresses the need for evaluating the impact of realistic geology on CO2 behaviour in the subsurface. We here demonstrate the effect of adding realistic complexity to the top reservoir morphology. A sensitivity matrix consisting of combinations of depositional and structural irregularities creating relief along the top of a reservoir was set up and the resulting models run in a fluid flow simulator monitoring CO2 plume dynamics. Results demonstrate the interaction between specific geological features and resulting plume behaviour and added retention capacity. Our study highlights the need to include realistic geology in models forecasting migration behaviour in subsurface reservoir.