A fully coupled method to model fracture permeability change in naturally fractured reservoirs

We present a new approach to model the fracture permeability change in naturally fractured reservoirs by combining a finite difference method (FDM) for fluid diffusivity equation in a fracture network, a fully coupled displacement discontinuity method (DDM) for the global relation of fracture deformation and the Barton-Band is joint deformation model for the local relation of fracture deformation. The method is applied to naturally fractured reservoirs under isotropic in-situ stress conditions and an isotropic in-situ stress conditions, respectively. The application of the new approach shows that the fracture permeability decreases with the pressure depletion under isotropic in-situ stress condition. Under highly anisotropic stress, it is possible that shear dilation can increase fracture permeability even as pore pressure decreases with production. Published by Elsevier Ltd.