Numerical investigation of heat transfer performance of water flowing through a reservoir with two intersecting fractures

Abstract

Understanding the water flow and heat transfer process in rock fractures is crucial for the development and utilization of geothermal reservoirs. This study develops a numerical model of a granite reservoir with two intersecting fractures to evaluate the heat production performance. Then, the evolution of the distribution of the rock and fluid temperatures is investigated. In addition, the effect of the injection temperature, heat transfer coefficient and injection flow velocity on the heat transfer characteristics are analyzed. Additionally, in order to study heat transfer performance with different fracture distributions, four cases of intersecting fractures with different angles are designed. The results indicate that, at different locations along the direction of seepage, the water temperature changes with time follow different rules. The results also show that, when the distribution of fractures is more uniform in the reservoir, the heat extraction rate of flowing water from the surrounding reservoir is faster. These results provided theoretical basis for geothermal system location selection, optimal selection of the reservoir stimulation scheme and reservoir thermal output prediction.