Multi-scale Reservoir Simulation Incorporating Permeability Evolution

In high-water-cut waterflood reservoirs, prolonged water injection induces significant changes in reservoir properties and leads to highly dispersed residual oil. While fine-scale reservoir simulation is vital for evaluating remaining oil potential, conventional simulators face two key challenges: the inability to directly model temporal property evolution and excessive computational demands. This study introduces a novel multi-scale simulation method (MsM) that explicitly incorporates dynamic permeability. Through experimental and field data, we characterized permeability changes using effective displacement flux and adjusted the black oil model equations. A multi-scale grid system was then constructed, and the pressure equation was solved via the multi-scale finite volume method, enhancing computational efficiency through parallel processing. Validation using the Egg model demonstrated that MsM reduces total simulation time by 59.26% and linear solver time by 92.53% compared to the traditional fully implicit method (FIM), with production curves and pressure/saturation distributions showing excellent agreement with FIM results. This method provides an efficient and accurate tool for simulating high-water-cut reservoirs, enabling more precise residual oil prediction and supporting optimized recovery strategies in mature oilfields.