Abstract: In the development of geothermal energy, U-shaped well closed heat exchange is adopted, and all reclaimed water is treated by a closed system. Its technical feature of "taking heat without taking water" avoids groundwater pollution caused by insufficient or leaking reclaimed water. The drilling of U-shaped wells requires precise point-to-point docking between vertical and horizontal sections, which is difficult to achieve with conventional directional drilling techniques due to the limitations of large well depth and trajectory adjustment. The research is based on existing magnetic guidance drilling technology. By increasing the number of magnetic columns on the magnetic short section to enhance the magnetic field strength, effective measures such as filtering noise reduction and angle compensation are adopted to improve measurement accuracy. At the same time, the magnetic guidance tools and operating process parameters are optimized to improve the detection range and applicability. The optimized magnetic guidance tool demonstrated good process performance in ground experiments, with an azimuth error of ±1.5°, a distance error of ±3%, and a temperature resistance of 175 ℃. This technology was applied to the Chaore R3-U1 well group in Daqing. Tracking measurements began at a depth of 3 907 m and magnetic guidance measurements were completed at a depth of 4 021 m. The azimuth deviation was only 0.16°, and the trajectory was accurately aligned with the target point of the vertical well. The research results have solved the technical problem of precise connection of geothermal U-shaped wells, achieved efficient extraction of geothermal energy, minimized groundwater pollution, and provided technical reference and on-site experience for the industrial promotion of advanced geothermal systems.