Phase-Field Modeling of Coupled Thermo-Hydromechanical Processes for Hydraulic Fracturing Analysis in Enhanced Geothermal Systems

Abstract

Abundant geothermal energy can be harvested from deep, low-permeability rocks using an enhanced geothermal system (EGS) that relies on an artificially created permeable fracture network through cold water injection. In this study, a two-way coupling technique for thermo-hydromechanical modeling was used to simulate hydraulic fracture propagation in an EGS. The transient heat and fluid flow in porous media were modeled using the finite volume method, while hydraulic fracture propagation and interaction with natural fractures were modeled using the variational phase-field method. Our findings underscore the importance of poroelastic and thermoelastic effects on fracture propagation in naturally fractured reservoirs. The results of this study demonstrate that thermo-hydromechanical processes are crucial elements in simulating and optimizing an enhanced geothermal reservoir system.

Keywords

• EGS
• phase-field approach
• thermal-hydromechanical coupling
• hydraulic fracturing
• OpenGeoSys