Analysis of Heat Extraction Rate of Open-Loop Geothermal Single Well System

China’s carbon peak and carbon neutrality commitments at the 75th UN General Assembly will greatly promote the use of green and clean energy in China. Geothermal energy is a clean, low-carbon, stable and reliable renewable energy, its development and utilization will contribute to the dual-carbon goal. Geothermal resources in China are mainly medium-low temperature, the traditional utilization mode of pumping hot water for heat exchange and then reinjecting has a high heat output. However, due to the difficulty of sandstone formation reinjection, it is currently limited in the Beijing-Tianjin-Hebei region of China. The close-loop of shallow and deep borehole heat exchangers has also been criticized for its low heat output. In contrast, the open-loop geothermal single-well system exchanges heat and mass with the formation, and the heat extraction rate is much higher than that of the close-loop system, which has become a research hotspot. In this paper, a flow and heat transfer model of the open loop geothermal single well system is established and numerically simulated, the effect of the position of the packer in the same aquifer and fluid flow rate on the reinjection pressure and the heat extraction rate of the single well is studied. The results show that: the position of the packer has a great effect on the reinjection pressure under large flow rate, while the position of the packer has little effect on the heat extraction rate under the same flow rate.