An assumed enhanced strain finite element formulation for modeling hydraulic fracture growth in a thermoporoelastic medium

Abstract

This paper presents an assumed enhanced strain finite element framework for simulating hydraulic fracture propagation in saturated thermoporoelastic media, considering the influence of thermal effects. The proposed approach combines classical thermoporoelasticity theory with a cohesive fracture model to describe the coupled behaviors of fluid flow, rock deformation and fracture propagation. Within this framework, fractures are represented using constant strain triangular elements enriched with constant displacement jumps. The mechanical response of fractures is governed by a trilinear cohesive law, and fracture initiation and propagation are both determined by using standard Newton’s method while maintaining global equilibrium. The numerical framework is verified through a series of examples, including cases without fractures, cases with rigid and deformable fractures, and hydraulic fracture propagation with thermal effects. The results show that thermal stress primarily affects the region near the injection point but has limited impact on fracture length evolution and fluid pressure distribution within the fracture. In contrast, temperature-dependent viscosity can significantly influence hydraulic fracture propagation. This work can be beneficial to our understanding of hydraulic fracture modeling in thermoporoelastic media and provide a potential useful numerical tool for simulating hydraulic fracturing processes with consideration of thermal effects.