Micro-Sweep Characteristics of CO2 Flooding

In this paper a micro multi-phase flow equation is built based on the mechanism of a multi-phase fluid flow in porous media. The authors consider the impact of convection diffusion and the improved component mixing rule. In order to accurately evaluate the fluid flow in a low permeability reservoir, two models are established to simulate simple pore throat structure and complex pore throat structure. The predicted residual oil distribution characteristics of CO 2 flooding in low permeability reservoir, calculated by finite element microsimulation, have been further verified by experiment. Furthermore, we analyze the effect of different wettability on microflow characteristics of CO 2 flooding. The results show that CO 2 flooding improving microsweep volume by convective diffusion is more evident in low permeability reservoirs than in high permeability reservoirs. The residual oil is mainly distributed following a pattern of prismatic, wedge-shape, or membrane microstructure. With decrease in the wetting angle on the fluid-rock boundary, the efficiency of oil displacement is further improved.