Impact of capillary pressure on permeability impairment during CO2 injection into deep saline aquifers

During CO2 injection in deep saline aquifers, salt precipitation happens around the injection well because of capillary driven back flow, inducing permeability impairment. The permeability impairment affects CO2 injectivity and migration. Different values of three characteristic parameters for capillary pressure function (air entry pressure, empirical parameter m and liquid residual saturation) as well as input absolute value of maximum capillary are chosen in numerical simulation to figure out their effects on salt precipitation. Verma & Pruess model is then used for quantifying permeability impairment. Results show that permeability decreases with higher air entry pressure, larger liquid residual saturation, and especially smaller value of empirical parameter m. To enhance CO2 injectivity and avoid blocking of CO2 migration, a homogenous formation with large pore size should be chosen before CO2 injection into deep saline aquifer.