Fracture propagation laws of staged hydraulic fracture in fractured geothermal reservoir based on phase field model

Abstract Hydraulic fracturing is widely used in geothermal resource exploitation, and many natural fractures exist hot dry rock reservoirs due to in-situ stress faults. However, the influence of on hydraulic fracture propagation not considered current study. In this paper, based phase field model, a thermo-hydro-mechanical coupled model was established reveal injection time, method, flow rate, distribution mechanism. The results show that complexity increases with an increase time. disturbance causes initiation pressure second cluster significantly higher than first third clusters. zipper-type method can reduce degree by 7.2% compared simultaneous fracturing. Both low high rate lead decrease which conducive complexity. An angle leads crossing fracture, but has lesser effect we analyzed different factors complexity, providing valuable guidance for exploitation resources.