微观储层岩石内孔隙率对砂粒流动的影响研究

Research on Influence of Porosity on Flow Behavior of Sand Grains in Micro-scale Rock Cracks

请采用DEM-CFD方法对微尺度储层岩石内沙粒流动特性进行模拟。建立了复杂形状的微通道模型,通过改变微通道的孔隙率,分析了沙粒在微通道中的速度分布、停留时间以及颗粒拟温度的分布。模拟结果表明,在形状复杂并且孔隙率低的情况下,沙粒极易被堵塞、沉积在微通道底部。随着孔隙率的增加,停留时间呈上升趋势;平均颗粒拟温度先增加后减小;颗粒轴向速度脉动幅度减小;而且颗粒接触力的平均值和标准方差也减小并且范围集中。

The flow behavior of sand grains in micro-scale rock cracks was simulated by means of DEM-CFD. Micro channel model with complex shape was established. Through changing the porosity of micro-channel, the velocity distribution, residence time of sand grains, and particle pseudo-temperature distribution in the micro-channel were analyzed. The simulation results show that, the sand grains easily deposit in the bottom of the micro-channel with complex shape and lower porosity to block the micro-channel. With increasing of the porosity, residence time is on the rise, average particle pseudo-temperature increases first and then decreases, while the mean particle axial velocity pulsation amplitude decreases, mean particle contact force decreases.