Influence of heterogeneous capillary pressure on CO2 sequestration in different wetting conditions

Abstract

In heterogeneous capillary pressure fields, a number of capillary barriers can exist and CO2 accumulates below them. This phenomenon is regarded as capillary trapping for CO2 sequestration. To analyze the amount of CO2 trapped and leakage, wettability as well as heterogeneity should be taken into account. Numerical simulations are undertaken to estimate the quantity of CO2 trapped by dissolution, residual, and capillary trapping under different heterogeneity and CO2/brine wettability scenarios. As the permeability variation increases, the amount of CO2 leakage decreases. In strongly water-wet system, the largest portion of stored CO2 is immobilized securely.