Reservoir engineering to accelerate the dissolution of CO2 stored in aquifers.

It is possible to accelerate the dissolution of CO2 injected into deep aquifers by pumping brine from regions where it is undersaturated into regions occupied by CO2. For a horizontally confined reservoir geometry, we find that it is possible to dissolve most of the injected CO2 within a few hundred years at an energy cost that is less than 20% of the cost of compressing the CO2 to reservoir conditions. We anticipate that use of reservoir engineering to accelerate dissolution can reduce the risks of CO2 storage by reducing the duration over which buoyant free-phase CO2 is present underground. Such techniques could simplify risk assessment by reducing uncertainty about the long-term fate of injected CO2, and could expand the range of reservoirs which are acceptable for storage.