Abstract: Natural fractures play the critical role in controlling fluid flow and in the heat transfer in carbonate geothermal reservoirs, and the connectivity of fracture networks directly determines the injection-production performance of well groups. Taking the Wumishan Formation in the JR block of Huabei Oilfield as the research object, this study adopts the damage mechanics method to quantitatively characterize the distribution of natural fractures in the reservoir. On this basis, a thermo-hydro-mechanical (THM) coupled finite element model is established to simulate the coupled deformation, seepage and heat transfer behaviors during well group injection-production, and to quantitatively evaluate the connectivity of inter-well fracture networks and to rank their performance. Based on the above methods, the injection-production capacities of 18 wells in the JR well group are calculated and analyzed quantitatively. Combined with the constraints of an alternate well arrangement, the total flow balance and the injection-production well ratio (1:1, 3:2), the well locations, and injection-production functions are optimized. After optimization, the overall balance of injection-production flow is achieved under the given injection-production pump pressure. The total water injection capacity and total water production capacity are increased by 12.1% and 6.73%, respectively, and the relative difference between total injection and production flow is reduced from 3.6% to 1.3%. The results show that the combination of damage mechanics and THM coupled numerical simulation provides an effective technical method for the fine characterization of natural fractures and for the optimization of injection-production schemes in fractured carbonate geothermal reservoirs. This study does not consider the fracture enhancement effects caused by weathering and acid fracturing, which will be further improved in future researches.