Simulation And Prospect Of Pore Type Geothermal Tail Water Reinjection In Sanqiao District Of Xi'an

In recent years,with the gradual increase of underground hot water exploitation in Xi'an City,over the years,underground hot water level declines seriously in Xi 'an because of exploitation no reinjection.In order to achieve the sustainable exploitation and utilization of underground hot water resources,underground hot tail water reinjection is one of the most effective and direct ways to ease or even resolve the decline of underground hot water levels.In the paper,numerical simulation is used to simulate the hydraulic connection between wells and wells,the evolution of reasonable well spacing,chemical field,seepage field and temperature field in the process of reinjection,and to predict the underground hot water level under different mining schemes after many years.And based on the results of the model,the future prospects for reinjection are forecasted in Xi'an.The research results are of great significance to the effective reinjection of geothermal tail water and the sustainable development and utilization of geothermal resources.In the paper,Xi'an Sanqiao Huisen Company mining and reinjection wells which have been studied in opened environment about underground hot water reinjection is the research object.Based on borehole data,geothermal geological data,water level and temperature monitoring data over many years,a medium-deep pore type geothermal water geothermal tail water reinjection numerical model was established.And the FEFLOW was used to transfer the solute of the wells to the wells.The reasonably well spacing,seepage field and temperature field were simulated,and the dynamic changes of underground hot water in the three-field under different recovery rates and different reinjection rates were predicted after 15 years.The simulation results show that the reasonable interval between wells for irrigation and irrigation is 200-250 meters.Under the condition of 100% reinjection rate,the water level decline value is the slowest for many years after the group soaking.It is suggested that the mining of medium-deep geothermal water in the Sanqiao area in the future must achieve a mining-to-well mining system,and strive to achieve a recharge rate of over 70% in order to achieve the sustainable development and utilization of underground hot water.