U型地热井作为开采中深层地热能的一种方式，其热开采效率的提高对地热储层的能源利用具有重要意义。为了研究U型地热井的换热特征及相关因素对热开采效率的影响，结合陕西黄陵地区地质与储层资料，通过建立3 500 m深U型地热井数值模型，对现场实验案例进行了模拟验证，重点分析了地热井井型、储层地温梯度和工况条件等因素对热开采效率的影响，并进一步对井型优选与参数优化做出了评价。研究结果表明：U型地热开采井相较于其他类型的地热井，在岩土地温梯度较高，尤其是管道埋深3 000 m以上的地区热开采效率更为突出；在本研究的参数选择范围内（注水流量分别为40、60、80、100、120 m³/h，注入温度分别为20、25、30、35、40 ℃），U型地热井的出入口的流体温差越大，换热量也就相应越高，研究区域U型地热开采井的注入流量采用100 m³/h，注入温度采用20 ℃为最佳，对于注入流量的选择需综合考虑出口温度和热开采功率的要求以及循环水泵的功耗进行设计。研究成果有望指导所在地区中深层地热开采的优化设计。

The U-shaped geothermal well, as a method for extracting medium-deep geothermal energy, is considered significant for enhancing the energy utilization efficiency of geothermal reservoirs. Geological and reservoir data from the Huangling area in Shaanxi Province were used to establish a numerical model of a U-shaped geothermal well with a depth of 3 500 meters. Field experiment cases were simulated and validated to investigate the heat transfer characteristics of U-shaped geothermal wells and the impact of related factors on thermal extraction efficiency. The effects of well type, reservoir geothermal gradient, and operational conditions on thermal extraction efficiency were analyzed, and the optimization of well type and parameters was further evaluated. The results indicate that U-shaped geothermal wells achieve higher thermal extraction efficiency compared to other types, particularly in areas with high geothermal gradients and depths exceeding 3 000 meters. Within the parameter range of this study (injection flow rates of 40, 60, 80, 100, and 120 m³/h, and injection temperatures of 20, 25, 30, 35, and 40 ℃), it was found that a larger temperature difference between the inlet and outlet fluids of the U-shaped geothermal well leads to a higher heat transfer rate. The optimal injection flow rate and temperature for U-shaped geothermal wells in the study area were determined to be 100 m³/h and 20 ℃, respectively. The selection of the injection flow rate should consider the requirements for outlet temperature, thermal extraction power, and the power consumption of the circulating water pump. The research findings are expected to provide guidance for optimizing medium-deep geothermal extraction in the region.