Numerical simulation of electricity generation potential through five vertical wells at Fengshun geothermal field in China

Fengshun geothermal field is the first medium low temperature geothermal field to exploit geothermal energy for electricity generation in China. Due to poor economy and low efficiency, the geothermal power plant was forced to shut down in 2016. In this work, based on the geological data of the well ZK11, we proposed a new heat exploitation scheme with five vertical wells and a binary system, computed the power generation potential and efficiency, and analyzed the main factors influencing heat production. The results indicate that through the five vertical wells, the system attains an electrical power of 1.49–1.05 MW, a reservoir impedance of 0.23–0.29 MPa/(kg/s), a pump power of 0.30–0.49 MW, and an electrical energy efficiency of 4.55–2.12. The electric power of unit flow rate is 22.4–31.7 times that of the existing power plant. Thus, this five-vertical-well system has significant development potential for medium low temperature hydrothermal field. The sensitivity analysis indicates that overburden and underburden permeability, water production rate and injection temperature have a significant impact on heat production performance. Increasing the overburden or underburden permeability will significantly reduce reservoir impedance and increase energy efficiency. Reducing the water production rate and injection temperature within a certain range can improve energy efficiency. This work also provides a guideline for the exploitation and power generation of future medium low temperature hydrothermal field in Fengshun and other sites under similar conditions.