利用孔隙网络模型模拟岩样中驱替过程的一种新方法

本文提出准动态驱替的概念以描述岩石内驱替速度介于准静态和动态之间的驱替过程.准动态模型在不同的尺度区别对待黏性力:将表征单元体(REV)尺度的驱替视为动态,而将孔隙尺度的驱替视为准静态.在REV尺度上,提出双重网络简化计算黏性力和毛管力的综合作用;在孔隙尺度上,运用概率方法描述界面在不同孔隙内的运动几率,提高了计算效率.通过与现有的计算和实验结果进行对比验证了模型的正确性,并基于特定岩石微CT扫描图像建立等价孔隙网络,计算分析了岩样内驱替速度、孔隙半径分布和孔隙角落形状对水驱油过程的影响.本文计算模型有利于认识岩石内水油两相驱替的动态全过程.

A new pore network based algorithm for water-oil displacements in core

The concept of quasi-dynamic displacement is presented to describe displacement with velocity between quasi-static and dynamic process. Viscousity is treated in different way in different scale： displacement in representative elementary volume（REV） scale is treated as dynamic, while displacement in pore scale is treated as quasi-static. In REV scale, double network is proposed for simplified calculation of viscous force and capillary force. In pore scale, probability technique is used to reduce computational demanding. The new model is validated by previous numerical and experimental results. With the network established based on specific micro CT scan images, the influences of displacement velocity, pore radius distribution and pore corner shape on water flooding process are analysed. The numerical model in this work is conducive to the understanding of the whole process of water-oil displacement.