Numerical Simulation of Fracture Propagation Characteristics Under Thermal-Hydraulic-Mechanical-Damage Coupling Effects During Hydrogen Storage in Tight Sandstone Gas Reservoirs

During hydrogen storage in tight sandstone gas reservoirs, the injection of low-temperature, high-pressure hydrogen induces thermal stress through cold shock, which significantly influences the initiation and propagation of fractures within the reservoir. However, the evolution characteristics of the stress and temperature fields in high-temperature rock matrix, as well as the initiation and propagation patterns of fractures under the coupled effects of low-temperature-induced thermal stress and in-situ stress, remain unclear. Therefore, a thermal-hydraulic-mechanical-damage coupling model was established to analyze the evolution characteristics of the stress and temperature fields in reservoir rocks, along with fracture propagation patterns, under varying stress conditions and injection temperatures. The results indicate that fractures propagate predominantly along the direction of the maximum principal stress. Additionally, larger temperature differences and smaller in-situ stress differentials favor the formation of complex fracture networks. This study holds significant implications for the safety and stability of hydrogen storage in depleted gas reservoirs.