Department of Civil Engineering,Tsinghua University

There is abundant geothermal resource in the intermediate⁃deep (200-3 000 m)and deep (>3 000 m)geo⁃thermal reservoirs in China,which has great potential for development,and the sustainable development and utilizationof geothermal energy is one of the important guarantees for carbon peaking and carbon neutrality goals to be achievedon schedule. However,the exploitation process of geothermal energy involves some complex interactions between tem⁃perature,seepage and stress fields. Therefore,the achievements on the coupled multi⁃field effects in the developmentof hydrothermal geothermal resources obtained by the authors are summarized,including the resource assessmentfor the sustainable development of urban deep geothermal energy, the method of optimal design of exploitationschemes,and demonstrated applications in typical geothermal engineering. A multi⁃index assessment system for thesustainable development of urban deep geothermal energy from the aspects of temperature, water level and deformation,as well as the calculation formula of recoverable geothermal energy based on numerical model are pro⁃posed. Based on the coupled multi⁃field numerical model of deep geothermal well⁃reservoir system,the method of re⁃coverable geothermal energy assessment which meets sustainable development criteria is presented,and the ‘trafficlight system’ for the risk assessment of production wells is proposed. Relying on the urban geothermal developmentproject in the Rongdong resettlement district of Xiongan New Area,the rationality of the proposed method of geothermalenergy assessment is demonstrated. Based on the coupled multi⁃field numerical model of deep geothermal well⁃reservoir system,the method of optimal design of exploitation schemes which meets the sustainable development criteriais presented,the surrogate model is constructed by the Plackett⁃Burman design,and the rapid optimization of parame⁃ters is realized by multiple response optimization. Relying on the urban geothermal development project in the Bei⁃jing Municipal Administrative Center,the rationality of the proposed method of optimal design of exploitation schemesis demonstrated. In this study, the theoretical and numerical supports for the sustainable development of urbandeep geothermal energy are provided,which promotes the development and utilization of urban deep geothermal energyon a larger scale and with higher quality.