Quantifying the Effects of Fluid Flow Along Faults on Formation Geomechanics: Implications for Stability and Reservoir Integrity

Abstract This study quantifies the effects of fluid flow along fault planes on the geomechanical response of subsurface formations, with a focus on the distribution of the displacement vector, stress-strain distribution, pore pressure changes and consequent changes in the displacement vector, as well as the stress and strain tensors. To achieve this, we developed the first-of-its-kind coupled flow and geomechanical model that leverages embedded discrete fracture model (EDFM) implemented for corner-point grids. Unlike the standard approach in traditional simulators that use fault-transmissibility multipliers to account for only flow across fault surfaces, the EDFM approach accounts for the effects of flow across and along fault faces on the mechanical response of the rock. It incorporates critical parameters such as fault permeability, fluid pressure gradients, and rock mechanical properties. By applying the model to simulate CO2 storage in the Johansen formation, we observed that neglecting the flow along the fault under-predicts the early-time changes in the geomechanical properties of the formation. These findings highlight the need to correctly model the flow in a fault as it can affect the geomechanical properties of the formation especially during the period of injection.