DYNAMIC STUDY ON OPTIMAL EXPLOITATION MODE OF GEOTHERMAL RESOURCES IN BEIJING TONGZHOU DISTRICT

Optimal exploitation of geothermal wells is of great significance to the intensive and efficient utilization of geothermal resources. According to the stratigraphic characteristics and the distribution of geothermal wells in Beijing Tongzhou District, a three-dimensional heat storage model was established. The multi-scale coupling simulation of heat and water in reservoir rock mass was carried out, and the model was calibrated using the monitoring data of pumping test and recharge test. Using the calibrated model, the thermal breakthrough time under different exploitation and recharge rates was calculated, and the variation of geothermal field caused by thermal breakthrough under the current mode and the evolution trend of pumping funnel with different exploitation rates were predicted. The dynamic contours of temperature field and water level field of 25 geothermal wells in Tongzhou area after 100 years of exploitation were predicted. Based on the above analysis and the current exploitation and recharge conditions, different well distribution plans were proposed, including "one exploitation well with one recharge well", "one exploitation well with two recharge wells" and "two exploitation wells with three recharge wells". Furthermore, numerical simulation of temperature field and water field with different exploitation and recharge flow rates were carried out, and the optimized well distribution mode was proposed, which provided a theoretical base for long-term development and utilization of geothermal resources.