地热采灌对井回灌温度场的模拟研究

Simulation research on reinjection temperature field of geothermal doublet well

利用地下水流数值模拟软件Feflow求解地热采灌对井系统水热耦合模型,进行温度场模拟研究。结果表明:在现状回灌温度为39.6℃时,5年后该系统回灌温度场影响半径为64 m,当回灌温度降低到13.5℃时,回灌温度场影响半径为68 m。该系统回灌温度场随采暖周期呈周期性变化,停灌后温度有所回升,说明该系统回灌尾水温度(39.6℃)偏高,且采灌井距(850 m)偏大,不利于热储水位流场的恢复。在进行地热对井回灌时,应根据热储层特征和布井场地条件,选择合适的采灌井距和回灌温度。

Applying the groundwater flow simulation software Feflow to solve the water-heat coupled model of geothermal doublet well system, the authors carry out the simulation study of the temperature field. The results show that ： under the status of recharge temperature is 39.6 ℃, the influence radius of recharge temperature field is about 64 m after five years; when the recharge temperature drops to 13.5 ℃, the influence radius of recharge temperature field is reach to 68 m. The recharge temperature field in this system changes periodically with the heating cycle, and the temperature increases after irrigation stopping. The fact indicates that recharge water temperature （39.6 ℃ ） of the system is high and distance of geothermal doublet well （850 m） is large, which is not conducive to the recovery of geothermal reservoir water level field. Therefore, geothermal doublet well reinjection should be select appropriate distance of geothermal doublet well and recharge temperature based on geothermal reservoir characteristics and well layout conditions.