Numerical simulation of temperature field and pressure field of the fracture system at Zhangzhou geothermal field

摘要

Zhangzhou geothermal field is one of the highest temperature in southeastern coastal areas in China. Zhangzhou geothermal field is an uplift-fracture type geothermal resource, and there are several deep fractures in the geothermal field, controlling water flow and heat transfer. Presently there is no systematic study of the characteristics of the temperature field, pressure field and water density distribution in the geothermal field, and there is no systematic analysis of the main factors affecting the temperature field. In this work, geological features of the fracture system are considered, and a conceptual model of the fracture system is established. Based on these, the distribution of the temperature field, pressure field and water density field at Zhangzhou geothermal field are numerically studied, the controlling effect of the fracture system on the temperature field is analyzed, and the main factors affecting the temperature field, pressure field and water density field are discussed. The results indicate that the temperature field and water density field at Zhangzhou geothermal field are strongly controlled by the fracture system, and the zone of high-temperature and low-density is confined within the fracture system. Main factors affecting the temperature field and water density field include the permeability of the fracture zone, the thermal conductivity of rocks and the water recharge rate. Higher fracture zone permeability will reduce the temperature and increase the water density in the center of the fracture system. Higher water recharge rate will increase the temperature and reduce the water density in the center of the fracture system.