Residual trapping, solubility trapping and capillary pinning complement each other to limit CO2 migration in deep saline aquifers

We derive a theoretical model for the post-injection migration of a CO2 gravity current in a confined, sloping aquifer under the influence of residual trapping, solubility trapping, and capillary pinning. The resulting model consists of two coupled partial differential equations that describe the local thickness of the buoyant CO2 current and the thickness of the mound of brine saturated with dissolved CO2 as a function of time. We apply this …