First-order multirate mass transfer for modeling coupled flow and deformation in heterogeneous fractured media

Abstract

Modeling fractured porous media is essential for the analysis of aquifers and underground reservoirs. The flow and deformation processes that occur both in the porous matrix and in the fracture network are key when studying phenomena such as land subsidence, induced seismicity or underground hydrogen storage. In this work we derive a first-order multirate mass transfer (MRMT) approach for the efficient numerical simulation of coupled flow and deformation in highly heterogeneous porous and fractured media. The model is predictive in the sense that the first-order exchange rates are parameterized in terms of the matrix geometry and permeability distribution. The performance of the numerical MRMT approach is demonstrated for the consolidation and drainage of a synthetic highly-heterogeneous fractured porous medium. The MRMT results are compared with high-fidelity direct numerical simulations that explicitly model flow and deformation in the detailed fracture–matrix system. This allows to account for rock fracturing in a realistic way when modeling processes such as induced seismicity or fluid storage in underground formations.