A Numerical Evaluation of the Impact of Wettability on CO₂ Trapping Capacity: Implications for Carbon Geo-Sequestration

Subsurface reservoir wettability is of vital importance in the prediction of CO₂ trapping capacity and containment security. However, quantifying the effect of reservoir wetting behavior on CO₂ sequestration potential in heterogeneous reservoirs remains to be challenging. This study conducts field-scale numerical simulations to understand the role of wetting characteristics and injection duration on the migration trend of CO₂ plume and trapping capacity. These simulations were conducted on a heterogeneous sandstone reservoir with realistic relative permeability curves. The results indicate that CO₂ plume migration and storage efficiency are influenced by wettability and injection duration. A water-wet system leads to higher residual gas trapping with less mobile CO₂ and less dissolution. Moreover, an increase in injection duration would result in a decrease in residual trapping but the solubility trapping and plume migration distance would both increase.