越流型单井系统含水层渗流传热规律研究  

Investigating the Seepage and Heat Transfer Law of Aquifers in the Leaky Type Single-Well System

作　　者：赵军[1,2] 宋超凡 尹洪梅 李默涵 李扬[1,2] Zhao Jun;Song Chaofan;Yin Hongmei;Li Mohan;Li Yang(School of Mechanical Engineering,Tianjin University,Tianjin 300350,China;Key Laboratory of Efficient Utilization of Low and Medium Grade Energy(Tianjin University),Ministry of Education,Tianjin 300350,China)

机构地区：[1]天津大学机械工程学院,天津300350 [2]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：《天津大学学报（自然科学与工程技术版）》2023年第4期333-345,共13页Journal of Tianjin University：Science and Technology

基　　金：天津市重点研发计划资助项目(20YFYSGX00020);中国科学院科技服务网络计划(STS计划)资助项目(KFJ-STS-QYZD-2021-02-006).

摘　　要：单井抽灌技术具有节约打井成本、盘活老井的经济优势,但由于存在热贯通问题,长期稳定的换热效率难以保证.而天然条件下的含水层多是由透水性较好的含水层和弱透水层组成的越流型结构,其中弱透水层由于具有低渗水性,可以有效地减缓含水层内的热贯通现象,对单井抽灌系统的可持续运行具有重要意义.鉴于弱透水层对越流型单井抽灌系统的取热效率有重要影响,同时越流型含水层的渗流规律尚不明确,因此有必要对其渗流传热规律进行研究.本文搭建了越流型单井抽灌系统室内渗流砂箱实验台,研究了弱透水层的存在对单井抽灌系统的传热特性以及含水层渗透性能的影响.结果表明,在边界补给充足的条件下,单井抽灌系统可以维持长期稳定的取热效率,4组不同抽灌流量工况下的稳定抽水温度分别为55.1℃、51.3℃、48.1℃、46.0℃,换热量分别稳定在0.93 kW、1.11 kW、1.18 kW、1.24 kW;含水层渗透系数随抽灌时间呈指数变化,抽水层渗透系数随抽水时间的增加而增大,而长时间回灌则降低了含水层的渗透性能,4组抽灌期的渗透系数分别减小27.0%、27.5%、28.1%、29.8%;根据实验结果得到了相对稳定时系统抽水温度的实验关联式以及含水层渗透系数的变化关系式.本文得到的研究结果可以为该类系统的后续研究提供一定的基础.Single-well pumping and recharging technology is economically advantageous as it saves well-drilling costs and revitalizes old wells.However,because of the thermal transfixion issue,it is difficult to ensure long-term stable heat exchange efficiency.Aquifers naturally are mostly leaky structures composed of well-permeable aquifers and aquitards.Among them,the aquitard has low water permeability,which can effectively reduce the thermal trans-fixion and is crucial to the sustainable operation of the single-well pumping and recharging system.The aquitard is also important for the heat extraction efficiency of the single-well pumping and recharging system;however,the seepage law of a leaky aquifer is not clear.Therefore,it is necessary to examine the seepage and heat transfer law.In this study,an indoor sandbox experimental platform for a leaky type single-well system is constructed to study the influence of the existence of an aquitard on the heat transfer characteristics of the single-well pumping system and the permeability of aquifers.The results indicate that when boundary replenishment is sufficient,the single-well pumping and recharging system can maintain long-term,stable heat extraction efficiency.The stable pumping temperatures under four groups of different pumping flow conditions are 55.1℃,51.3℃,48.1℃and 46.0℃,and the heat exchange is stable at 0.93 kW,1.11 kW,1.18 kW and 1.24 kW,respectively.The permeability coefficient of the aquifer varies exponentially with the pumping and recharging time.It increases with the increase in pumping time,while long-time reinjection reduces the permeability of the recharging aquifer.Moreover,the permeability coefficients of the recharging aquifer of the four pumping and recharging periods decrease by 27.0%,27.5%,28.1%and 29.8%,respectively.According to the experimental results,the experimental correlation equations of the system pumping temperature and the aquifer permeability coefficient change equations are obtained when the system is relatively stable.The resul

关 键 词：地热能 单井抽灌 砂箱实验 弱透水层 渗流传热 

分 类 号：TK448.21[动力工程及工程热物理—动力机械及工程]