Homogeneous equivalents of naturally fractured porous media for miscible fluid displacements

Abstract

The displacement of one fluid by another miscible fluid in fractured porous media was investigated. The possibility of using an equivalent porous medium model (continuum model) was studied using a three-dimensional particle walk model which is capable of handling nearly one million grid blocks. It was shown that, for a given set of fracture properties, there exists a range of number of fractures within which a homogeneous porous medium with equivalent properties can be used to describe the behavior of the system. Furthermore, a technique is proposed to reduce the number of grid blocks used in simulation for cases where detailed fracture representation results in an excessive number of grid blocks. A data reduction technique is presented which shows that a given network can be reduced from one million grid blocks to 36,000 grid blocks. Miscible displacement simulations carried out in both networks show that the reduced network behaves similar to the original one.