A dynamic coarsening approach to immiscible multiphase flows in heterogeneous porous media

We have developed a sequential approach to accelerate immiscible multiphase flow modelling in heterogeneous porous media using discontinuous Galerkin methods and dynamic mesh coarsening. This approach involves dynamic domain decomposition and different solution strategies in the different flow regions, using a criterion that can be fastly evaluated. We use high-resolution grids and low order methods in the multiphase flow regions near the saturation discontinuity and a discontinuous Galerkin method along with low-resolution grids in single-phase flow regions of the domain. We present a fast technique to estimate the position of the saturation front and identify the flow zones that need high-resolution gridding. We demonstrate the accuracy of our approach through test cases from the second SPE10 model by comparing our results with fine-scale simulations.