单井采灌系统现场试验研究及理论模型构建  

Field Experimental Study and Theoretical Model Development on the Pumping Recharging Geothermal System of the Single Well

作　　者：马凌 尹洪梅 杨轩 宋超凡 赵军[1] MA Ling;YIN Hongmei;YANG Xuan;SONG Chaofan;ZHAO Jun(Key Laboratory of Efficient Utilization of Low and Medium Grade Energy(Tianjin University),Ministry of Education of China,Tianjin 300350,China)

机构地区：[1]中低温热能高效利用教育部重点实验室(天津大学),天津300350

出　　处：《工程热物理学报》2022年第7期1942-1950,共9页Journal of Engineering Thermophysics

摘　　要：设计并建立了全长1764 m深的单井采灌换热试验系统并进行60 h的抽水–换热–回灌试验,结果表明封隔器坐封条件下抽水温度和换热量平均值分别为56.31℃和1020 kW,远高于无坐封的开放式井底的单井采灌系统。基于“分区解耦建模+耦合求解”的计算方法提出了单井采灌换热系统传热流动理论模型,通过对导热区和采灌区耦合计算,可获得采灌区降深分布、越流量、抽水温度及换热量等随时间的演变函数。模型计算表明,抽水层与回灌层降深变化高度一致,水头影响半径增长速度远高于热影响半径;越流量随着时间增速放缓,抽水温度随时间略有衰减;系统最大理论换热量为1428 kW,内外管引起的热量损失为401 kW,约占最大总换热量的28.08%。A field experiment was designed and conducted to study the pumping recharging geothermal system of the single well with the depth of 1764 m,and the experimental studies of the groundwater pumping,heat transfer and recharging processes were completed with the duration of 60 h.The experimental results indicated that with the sealed rubber packer condition,the average values of the outlet groundwater temperature and heat transfer rate are 56.31℃ and 1020 kW,respectively,much larger than the experimental results with the unsealed rubber packer condition.Based on the research approach of “decoupling modeling of every partition and coupling calculation”,the theoretical models of the pumping recharging geothermal system of the single well were constructed to describe the heat transfer and groundwater flow processes.By coupling the calculations of the heat conduction zone and pumping recharging zone,the models could develop the variation functions of drawdowns in the pumping and recharging aquifers,leakage groundwater flowrate through the aquitard,outlet groundwater temperature and heat transfer rate.Theoretical calculation indicated that the drawdown functions of the pumping aquifer coincided exactly with that of the recharging aquifer,and the hydraulic-affected zone grew quickly than that of thermal-affected zone.The leakage groundwater flowrate through the aquitard grew slowly with time and the leakage caused a slight decrease of the outlet groundwater temperature during the experimental duration.The maximum heat transfer rate was 1428 kW,and the heat loss caused by the thermal interference between the upward flow in the annular zone and downward flow in the inner pipe was 401 kW,accounting to28.08% of the maximum value.

关 键 词：地热能 单井采灌系统 理论模型 越流 含水层 

分 类 号：TK529[动力工程及工程热物理—热能工程]