Evaluation of the Fault Activation Risk Induced by Hot Dry Rock Reservoir Development Based on Thermal–Hydraulic–Mechanical Coupling

Due to the nature of hot dry rock resources and the particularity of the development methods, the fault activation induced by injection and production of hot dry rocks involves a complex multifield coupling mechanism. Traditional methods cannot effectively evaluate the fault activation behavior in hot dry rock injection and production. Aiming at the above-mentioned problems, a thermal-hydraulic-mechanical coupling mathematical model of injection and production of hot dry rocks is established and solved by a finite element method. At the same time, the fault slip potential (FSP) is introduced to quantitatively evaluate the risk of fault activation induced by injection and production of hot dry rocks under different injection and production conditions and geological conditions. The results show that under the same geological conditions, the greater the well spacing of injection and production wells, the greater the risk of fault activation induced by injection and production and the greater the injection flow, the greater the risk of fault activation. Under the same geological conditions, the lower the reservoir permeability, the greater the fault activation risk and the higher the initial reservoir temperature, the greater the fault activation risk. Different fault occurrences result in different risks of fault activation. These results provide a certain theoretical reference for the safe and efficient development of hot dry rock reservoirs.