Accelerating The Dissolution of CO2 in Aquifers

Abstract Assessments of aquifer storage capacity and security have generally assumed that reservoir engineering would be limited to site selection and placement of the injection wells. In previous work we have shown that it is possible to accelerate the dissolution of CO2 in brines by active reservoir engineering achieved by pumping brines from regions where it is undersaturated into regions occupied by CO2 [1]. Here we report 2and 3-D reservoir simulations of aquifers with/without horizontal confinement and with/without inhomogeneity. For a horizontally confined reservoir geometry, we find that it is possible to dissolve essentially all injected CO2 within 300 years at an energy cost that is less than 10% of the cost of compressing the CO2 from atmospheric pressure to reservoir conditions. We anticipate that reservoir engineering to accelerating dissolution can simplify risk assessment and permitting of storage projects, and will expand the number and geographic extent of reservoirs which are acceptable for storage.