中深层地热U型井地埋管换热器的试验研究  

Experimental investigation on U-type ground heat exchanger of medium-deep geothermal energy

作　　者：李振兴[1] LI Zhenxing(Hydrogeology Bureau of China National Administration of Coal Geology,Handan 056004,China)

机构地区：[1]中国煤炭地质总局水文地质局,河北邯郸056004

出　　处：《热科学与技术》2023年第4期399-407,共9页Journal of Thermal Science and Technology

基　　金：河北省重点研发计划项目资源与环境专项资助项目(20374503D);中国煤炭地质总局中深层地热能开发利用科技创新团队(T-03)资金资助项目。

摘　　要：为了了解中深层地热U型井地埋管换热性能及井下换热参数变化,完成了新型的U型井地埋管换热器工程,并在此基础上进行了实验研究。首先,确定了研究区的地层温度,根据热储的物性条件选取了水平井段及对接位置;其次,分析空载循环试验工况下循环水的流量及井下温度的变化情况,研究了负载工况下供回水温度、流量、换热量、不同井段对换热的贡献率、井下温度的动态变化、U型井的恢复能力等因素。实验结果表明:中深层U型井地埋管换热器井底温度会随运行时间增长而降低,流量大且回水温度较低的情况下,换热器的换热量比较高,最高为1 336.8 kW;回水井对换热量的增加有限,每百米增加0.12℃,实际工程中可以考虑减小口径,降低建设费用;U型井地埋管换热器的地温恢复能力较强,停止运行24 h左右井底温度与初始温度差为-13.00℃。研究结果有助于研究人员对中深层U型井地埋管换热器有更进一步的认识,从而推动中深层地热能的健康可持续发展。In order to understand the heat transfer performance of underground pipes and the change of downhole heat exchange parameters of medium and deep geothermal U-shaped wells,the new U-shaped underground pipe heat exchanger project was completed,and experimental research was carried out on this basis.Firstly,the ground temperature was measured,the formation temperature of the study area was determined,and the horizontal well section and docking location were selected according to the physical conditions of heat storage.Secondly,the flow rate of circulating water and the change of downhole temperature under no-load cycle test conditions were analyzed,and the factors such as supply and return water temperature,flow rate,heat exchange amount,contribution rate of different well sections to heat exchange,dynamic change of downhole temperature,and recovery ability of U-shaped wells under load conditions were studied.The experimental results show that the temperature at the bottom of the buried pipe heat exchanger in the medium and deep U-shaped wells will decrease with the increase of operating time,and the heat exchange of the heat exchanger is relatively high when the flow rate is large and the return water temperature is low,up to 1336.8 kW;the rise of heat exchange amountwith the return well is limited,increasing by O.12℃ per 100 meters.The ground temperature recovery ability of the U-shaped underground pipe heat exchanger is strong,and the difference between the bottom temperature and the initial temperature is -13.0℃ after stopping operation 24 h.The results of the study will help researchers to have a better understanding of the buried tube heat exchanger in medium and deep U-shaped wells,so as to promote the healthy and sustainable development of medium and deep geothermal energy.

关 键 词：地热能 地埋管换热器 换热试验分析 光纤测温 中深层地热U型对接井 

分 类 号：P314[天文地球—固体地球物理学] TK11[天文地球—地球物理学]