Thermo-Hydro-Mechanical Coupled Optimization of the Layout of Egs Subregions with Different Depths for Commercial Utilization

In this work, a three-dimensional T-H-M model is proposed to explore the optimal layout of EGS subregions for commercial utilization of EGS. The results show that the main flow path is in the fracture surface, and the flow dominant area is concentrated between the production and injection wells. The fracture displacement changes due to the variation of reservoir temperature and pressure, which alters the reservoir permeability and finally determines the transport characteristics in the reservoir. With the progress of the production, the flow dominant region is strengthened while the region with the weak flow is weakened, resulting in sufficient heat extraction in the central region and insufficient heat extraction near the marginal region. To improve the heat extraction of EGS, the fluidity of the marginal region needs to be improved. Under different commercial injection conditions, the EGS subregions that meet Standard 1 and Standard 2 are obtained with different combinations of depth and width, which provides basic guidance for future research. The fracture structure is particularly important during the construction of thermal storage. The width of fracture should reach a certain value to effectively reduce the injection pressure and improve economic efficiency