Method to assess the impact of existing fractures and faults for reservoir management

Assessing the impact of existing fractures and faults for reservoir management, in one aspect, may comprise employing a numerical mesh to generate a geomechanical model, the numerical mesh representing a geological reservoir and its surrounding regions, the numerical mesh comprising delimitation associated with regions and layering of geology without constraining the numerical mesh to explicitly represent a fault or fracture, initializing the geomechanical model to define initial stress-strain compatible with measured stress in well locations associated with the geological reservoir, generating a fluid-flow model employing the numerical mesh, solving for a coupled solution of the fluid-flow model and the geomechanical model, and employing the solved fluid-flow model and the geomechanical model to assess the impact.