Enhancing CO2 dissolution in saline aquifers: Sensitivity analysis of well configuration and water injection strategies

Carbon dioxide (CO 2 ) sequestration in deep saline aquifers is a viable large-scale strategy for reducing anthropogenic emissions; however, the impact of operational design on dissolution trapping efficiency remains insufficiently quantified. This study systematically evaluates the influence of injection strategy, well configuration, and pressure management on CO 2 dissolution using compositional simulations in CMG-GEM over a 200-year period. A heterogeneous aquifer model was developed, and systematic sensitivity analyses were performed to identify key operational parameters governing CO 2 solubility and plume stability. Intermittent CO 2 injection improved long-term dissolution compared with continuous injection by enhancing CO 2 –brine contact and convective mixing. Well placement significantly influenced storage performance. Central injector positioning increased dissolution by 8%, 20%, and 5% under WAG, SWAG, and no-water-injection scenarios, respectively, compared with edge placement. Strategic brine extraction improved pressure stability, with 1000 m injector–extractor spacing providing the most favorable long-term pressure control and sustained dissolution enhancement. Horizontal wells yielded approximately 5% higher dissolution efficiency than vertical wells due to increased reservoir contact area. Pressure-management through brine extraction emerged as one of the most influential operational control, followed by water-assisted injection and well placement. Overall, maximizing CO 2 –brine contact while maintaining favorable reservoir pressure conditions was identified as the primary mechanism governing dissolution trapping. These findings provide a practical engineering framework for improving long-term storage security in saline aquifers through enhanced solubility trapping.