Coupled Thermo-Hydro-Mechanical Modeling on the Rongcheng Geothermal Field, China

Numerical reservoir modeling plays an important role in understanding and predicting the performance of geothermal reservoirs to varying exploitation schemes. In this study, four parameters including thermal breakthrough time, water level and vertical displacement at the production wells and the recoverable energy in the licensed region are selected to assess the potential exploitation schemes. An integrated model combining the simplified 1D geothermal well model and the 3D geothermal reservoir model is developed to simulate the fully coupled thermo-hydro-mechanical (THM) processes in geothermal reservoirs including multiple wells, and the measured surface settlement data in the Geysers geothermal field is used to validate the reasonability and efficiency of the developed modeling method. A case study of the Rongcheng geothermal field, China, is presented to clarify the important role of coupled THM processes in the sustainable exploitation of geothermal resources. The results show that the developed integrated model is a robust simulation tool to understand and predict the performance of city-scale geothermal fields under different patterns of well groups. The production wells may not reach the designed lifetime due to various natural or artificial reasons, so the optimal well patterns should be designed to maximize the recoverable geothermal energy considering the natural properties of geothermal reservoirs.