Simulation of Co2 Plume in Porous Media: Consideration of Capillarity and Buoyancy Effects

IMplicit Pressure Explicit Saturation (IMPES) scheme with treating buoyancy and capillary forces is used to solve the two-phase water-CO2 flow problem. In most of the previous studies of the two-phase flow, the buoyancy force term was ignored; however, in the case of liquidgas systems such as water-CO2, the gravity term is very important to express the buoyancy effect. In this paper, we present three numerical examples to study the CO2 plume in homogeneous, layered, and fractured porous media. In each numerical example, we tested four different models by ignoring both gravity and capillary pressure, considering only gravity, considering only capillary pressure, and considering both gravity and capillary pressure. The cell-centered finite difference (CCFD) method is used to discretize the problem under consideration. Furthermore, we also present the stability analysis of the IMPES scheme. The numerical results demonstrate the effects of the gravity and the capillary pressure on the flow for the four different cases.