Thermo-Hydro-Mechanical Coupling Processes in Carbonate Geothermal Reservoirs and Their Numerical Simulation

Abstract Reinjecting low-temperature tailwater into geothermal reservoirs leads to complex thermo-hydro-mechanical coupling processes, making it more difficult predict the thermal breakthrough of reservoirs. By taking example deep carbonate karst fissure type in Xianxian field China, this paper studied processes case reinjection based on previous tracer tests. It established a three-field model two-dimensional discrete fracture network and further verified its suitability through inversion analyses. Moreover, discovered regularity effects temperature pressure changes deformation rock masses clarified mechanisms seepage heat transfer processes. Meanwhile, presented extraction efficiency production well production-reinjection system field. As indicated by results, increased decreased, respectively, initial phase reinjection, leading an increase aperture reservoir permeability. Then, they tended gradually stabilize, amplitude change permeability decreased as proceeded. Finally, proposed optimized scheme study area, aiming provide scientific support for reinjection.