Pore‐scale flow simulation of high‐viscosity crude oil in anisotropic pore channels

Abstract Anisotropy is one of the key factors affecting reservoirs development. Previous studies on anisotropic porous media reservoirs have predominantly centred on continuous‐scale and regular models, while studies about irregular pore‐scale anisotropic reservoirs are relatively less frequent. This study aims to establish an irregular anisotropic pore scale reservoir model and investigate its flow characteristics. A two‐dimensional irregular anisotropic pore scale reservoir model is established by using the quartet structure generation set (QSGS) method. By computational fluid dynamics (CFD), a numerical simulation analysis is performed to compares the differences in absolute permeability, heavy oil recovery rate, and remaining oil distribution in different directions. The results indicate that the differences of absolute permeability are relatively small within the same (horizontal or vertical) direction. However, the absolute permeability of horizontal direction is approximately twice that of the vertical direction. When the water injection velocities increase from 0.001 to 0.015 m · s −1 , the differences in horizontal direction of heavy oil recovery rates are very small, all less than 0.0933. However, they are relatively large in the vertical direction, all greater than 0.1778. Under the same conditions (except for different combinations of water injection inlet and outlet), the heavy oil recovery rate is positively correlated with the average pore length on the water injection inlet side. The longer the average pore channel length on the inlet side, the higher the heavy oil recovery rate.