Analysis of Hydraulic Fracture Propagation Behavior Using a Thermo-Hydro-Mechanical Coupled Model

Hydraulic fracturing is a key reservoir stimulation technology for enhancing hydrocarbon recovery from unconventional reservoirs. However, fracture initiation and propagation are governed by complex thermo-hydro-mechanical (THM) coupling processes, which strongly influence fracture geometry, propagation dynamics, and overall reservoir stimulation efficiency. In this study, a fully coupled THM numerical model is developed to investigate the multiphysics mechanisms governing hydraulic fracture initiation, propagation, and evolution under realistic reservoir conditions. Beyond hydraulic fracturing applications, the proposed framework can also be extended to analyze fracture propagation, multiphase fluid migration, and coupled rock–fluid interactions in subsurface energy systems, including geological carbon storage and geothermal energy extraction. The simulation results demonstrate that reservoir temperature and reservoir pressure significantly influence fracture propagation by altering the pressure differential between the hydraulic fracture and the in situ stress field. Elevated reservoir pressure promotes fracture extension, whereas elevated reservoir temperature suppresses fracture propagation by increasing fluid leak-off and accelerating pressure dissipation. Furthermore, molecular-scale analyses are conducted to interpret how thermodynamic conditions influence intermolecular interactions, fluid behavior, stress transfer, and fracture evolution, and the macroscopic simulation results are interpreted in light of molecular-scale hypotheses drawn from previous literature concerning intermolecular interactions, hydrogen bond network evolution and polymer adsorption. These findings provide new insights into the coupled THM mechanisms controlling fracture evolution and establish a theoretical basis for optimizing hydraulic fracturing strategies, improving energy recovery efficiency, and advancing subsurface energy engineering applications. The proposed framework also provides valuable guidance for the sustainable development of unconventional hydrocarbon resources, enhanced geothermal systems, and geological carbon storage technologies, thereby contributing to long-term energy security and sustainable energy supply.