Numerical Analysis of Thermal Recovery Performance of Enhanced Geothermal System

In order to analyze the effects of fracture width and fluid velocity on the heat transfer performance of enhanced geothermal system, this paper uses CO2 as the heat transfer medium of EGS, adopts the orthogonal experimental design method, selects a three-factor and three-level orthogonal experimental table, and analyzes the effects of fracture width and fluid velocity in the fracture on the heat recovery performance of ESG and its change law based on CFD method. The analysis results show that: the influence of fluid velocity on reservoir heat recovery performance is greater than that of fracture width on reservoir heat recovery performance; the net heat extraction rate of the system decreases with the decrease of fluid velocity in the fracture and decreases with the decrease of fracture width; the reduction rate of net heat extraction rate of the system increases about 10% for each decrease of fluid velocity in the fracture by 0.001 m/s; the reduction rate of single-slit heat extraction rate increases about 10% for each decrease of fracture width by 0.002 m. The reduction rate of net heat extraction rate increases by about 3% for each 0.002 m reduction in fracture width.