Based on a comprehensive review of domestic and foreign literature, this article discusses the technical difficulties and development status of enhanced geothermal system(EGS) concerning the thermal energy extraction ...Based on a comprehensive review of domestic and foreign literature, this article discusses the technical difficulties and development status of enhanced geothermal system(EGS) concerning the thermal energy extraction of deep hot dry rock(HDR) reservoirs and proposes suggestions for the research focus of numerical simulation of HDR reservoir stimulation. Additionally, it summarizes the existing methods and mainstream working fluids for HDR reservoir stimulation. The article emphasizes the significance of factors such as well location, production well depth, artificial fracture orientation, and complexity in optimizing the thermal production efficiency of the EGS. Furthermore, this article delves into a detailed discussion on the influence of fracture spacing, fracture permeability,fracture length, fluid injection rate, and injected fluid temperature on the performance of the EGS. In light of the thermo-hydro-mechanical coupling challenges associated with high-temperature reservoirs, it is suggested that future research efforts should focus on investigating the impact of thermo-induced stresses on the stability of the artificial fracture network within the EGS during long-term(>30 years) circulation of hot and cold fluids.展开更多
Hot dry rock,as a renewable and sustainable energy source,can alleviate resource shortages and environmental pollution.Based on data from the Qiabuqia geothermal field and an established thermal-hydrological-mechanica...Hot dry rock,as a renewable and sustainable energy source,can alleviate resource shortages and environmental pollution.Based on data from the Qiabuqia geothermal field and an established thermal-hydrological-mechanical coupled mathematical model,a novel horizontally layered enhanced geothermal system(EGS)is proposed and compared with the conventional double vertical well EGS.Under the simulated conditions in this paper,the comprehensive heat recovery performance of the horizontally layered EGS is significantly better than that of the double vertical well EGS.Specifically,although the average production temperature of the double vertical well EGS is higher than that of the horizontally layered EGS in the attenuation stage,the heat power output of the horizontally layered EGS ranges from 6.10 MW to 12.25 MW,which is 1.36 to 1.67 times that of the double vertical well EGS.Additionally,the heat recovery rate of the horizontally layered EGS is 6.63%higher than that of the double vertical well EGS and is thus more economical.Finally,parametric analysis was performed to investigate the influence of the controllable parameters on heat recovery for the horizontally layered EGS.The heat power output and heat extraction ratio are proportional to the pressure difference and well spacing and inversely proportional to the injection fluid temperature.The thermal power output is most greatly influenced by the pressure difference,followed by the well spacing and injection fluid temperature.The effects of the pressure difference and well spacing on the heat recovery rate are almost the same,and the injection fluid temperature has no effect.展开更多
基金Research Foundation of the Department of Natural Resources of Hunan ProvinceGrant/Award Number:20230101DZ+7 种基金Natural Science Foundation of Hunan ProvinceGrant/Award Number:2023JJ20062National Key Research and Development Program of ChinaGrant/Award Number:2022YFC2903704National Natural Science Foundation of ChinaGrant/Award Number:52104112Science and Technology Innovation Program of Hunan Province of ChinaGrant/Award Number:2023RC3051。
文摘Based on a comprehensive review of domestic and foreign literature, this article discusses the technical difficulties and development status of enhanced geothermal system(EGS) concerning the thermal energy extraction of deep hot dry rock(HDR) reservoirs and proposes suggestions for the research focus of numerical simulation of HDR reservoir stimulation. Additionally, it summarizes the existing methods and mainstream working fluids for HDR reservoir stimulation. The article emphasizes the significance of factors such as well location, production well depth, artificial fracture orientation, and complexity in optimizing the thermal production efficiency of the EGS. Furthermore, this article delves into a detailed discussion on the influence of fracture spacing, fracture permeability,fracture length, fluid injection rate, and injected fluid temperature on the performance of the EGS. In light of the thermo-hydro-mechanical coupling challenges associated with high-temperature reservoirs, it is suggested that future research efforts should focus on investigating the impact of thermo-induced stresses on the stability of the artificial fracture network within the EGS during long-term(>30 years) circulation of hot and cold fluids.
基金supported by the Fundamental Research Funds for the Central Universities(No.2020ZDPY0222)。
文摘Hot dry rock,as a renewable and sustainable energy source,can alleviate resource shortages and environmental pollution.Based on data from the Qiabuqia geothermal field and an established thermal-hydrological-mechanical coupled mathematical model,a novel horizontally layered enhanced geothermal system(EGS)is proposed and compared with the conventional double vertical well EGS.Under the simulated conditions in this paper,the comprehensive heat recovery performance of the horizontally layered EGS is significantly better than that of the double vertical well EGS.Specifically,although the average production temperature of the double vertical well EGS is higher than that of the horizontally layered EGS in the attenuation stage,the heat power output of the horizontally layered EGS ranges from 6.10 MW to 12.25 MW,which is 1.36 to 1.67 times that of the double vertical well EGS.Additionally,the heat recovery rate of the horizontally layered EGS is 6.63%higher than that of the double vertical well EGS and is thus more economical.Finally,parametric analysis was performed to investigate the influence of the controllable parameters on heat recovery for the horizontally layered EGS.The heat power output and heat extraction ratio are proportional to the pressure difference and well spacing and inversely proportional to the injection fluid temperature.The thermal power output is most greatly influenced by the pressure difference,followed by the well spacing and injection fluid temperature.The effects of the pressure difference and well spacing on the heat recovery rate are almost the same,and the injection fluid temperature has no effect.