International Journal of Heat and Mass Transfer, Vol.96, 396-405, 2016
Multiscale mixed finite element, discrete fracture-vug model for fluid flow in fractured vuggy porous media
Numerical simulation in naturally fractured-vuggy media is challenging because of the coexistence of porous media, fractures and vugs on multiple scales that need to be coupled. We present a new approach to reservoir simulation, based on the discrete fracture-vug network (DFVN) model, which gives accurate resolution of both large-scale and fine-scale flow patterns. In this work, we use a multiscale mixed finite element method (MsMFEM) for fluid flow in fractured-vuggy media using the discrete fracture-vug model. By combining MsMFEM with the discrete fracture-vug model, we aim towards a numerical scheme that facilitates fractured vuggy reservoir simulation without upscaling. MsMFEM uses a standard Darcy model to approximate the pressure and velocity on a coarse grid, whereas fine scale effects are captured through basis functions constructed by solving local flow problems using the discrete fracture-vug model. The accuracy and the robustness of MsMFEM are shown through several examples. In the first example, we consider Beavers-Joseph model and then compare the analytic solution. We use the MsMFEM in more complex models. The results indicate that the MsMFEM is a promising path toward direct simulation of highly resolution geomodels. (C) 2015 Elsevier Ltd. All rights reserved.