Research progress of technologies and numerical simulations in exploiting geothermal energy from abandoned wells: A review

Exploiting geothermal energy from abandoned wells is one of the current international research hotspots, while there is a lack of introduction on the research progress of technologies and numerical simulations at present. Aiming at this problem, the research progress of geothermal development of abandoned wells is systematically investigated and summarized. The heat extraction technologies include open-loop heat extraction and closed-loop heat extraction. Flash steam system and binary cycle system are the main technologies that be used in geothermal power generation, and direct utilization of heat energy is also a good choice. The main study object of the numerical simulation of abandoned wells is closed-loop heat extraction. There are already some mathematical models for reference, but the relevant conclusions of these models need to be further verified by more field tests. By analyzing the existing research results and problems, it is considered that the screening of abandoned wells that have the potential to exploit geothermal energy, the creation and optimization of production and utilization technologies, etc. are important research directions in the future.