Numerical Simulation on the Heat Recovery Law of Exploiting Geothermal Energy from a Closed-Loop Geothermal System Converted from an Abandoned Five-Spot Well Pattern

[Image: see text] Exploiting geothermal energy from abandoned wells is a research hotpot at present. However, there is still a lack of research on exploiting geothermal energy using an abandoned well pattern. Aiming at this problem, in this paper, a novel method for exploiting geothermal energy from an abandoned well pattern is proposed. An unsteady heat transfer model is proposed to study the influence of some key parameters on the production law of the novel scheme, and the proposed model is verified with field experimental data. The result indicates that there exists a critical flow rate that can change the form of the characteristic curve of the outlet temperature with production time. The change of flow rate has more influence on the outlet temperature than that of temperature. A higher geothermal gradient is conducive to production. When the total number of wells and the total flow rate of the system are fixed, fewer production wells will be conducive to production. When the number of production wells and injection wells is determined, changing the deployment of production wells and injection wells has little effect on the outlet temperature and thermal power.