The large-scale effects of multiple CO2 injection sites on formation stability

AbstractWe present results of a recent study investigating consequences of large scale deployment of CO2 sequestration within a region spanning tens of kilometers. This initial study considered a faulted aquifer bounded above and below by impermeable rock. We performed a parameter study of fault activation due to elevated pore pressures and addressed several combinations of injection scenarios and in situ stress orientations. The simulations were performed using iteratively coupled flow and geomechanical capabilities. For each scenario, a multiple fluid injection was simulated using a non-steady reservoir flow model. At various phases of injection, the pore-pressure field was mapped over to our geomechanical codes to evaluate the evolving stress state throughout the region of interest. The geomechanical analysis specifically investigated the potential for fault activation. The results of the geomechanical simulations were used to update the flow model and modified the subsequent CO2 plume and pressure perturbation. In addition to demonstrating large scale coupled fluid-geomechanical solver capabilities, the results highlight the importance of site selection, site characterization and in situ stress determination. The results also emphasize that site specific injection scenarios will be required for regions with substantial sequestration resource to manage permitting and deployment in such a way as to avoid unintended negative consequences of large-scale deployment