Optimized Design of Downhole Magnetic Source for U-Well Magnetic Guidance System

This study focuses on the optimization of the downhole magnetic source of the U-shaped well magnetic guidance system, aiming to improve the system performance to meet the needs of efficient and safe energy development. The study utilizes theoretical calculations, finite element analysis, and experimental tests to investigate the design of the downhole magnetic source. For the selection of permanent magnet materials, N42H NdFeB permanent magnets are selected after complete consideration of multiple factors, and their performance is verified through temperature-resistant experiments. For the φ172 magnetic node, the maximum diameter of the permanent magnet is determined to be 30 mm. Through theoretical, simulation, and experimental studies on the distribution of magnetic induction intensity under different aperture layouts, it is found that for a specific layout, the signal can be received at a distance of 120 m away from the magnetic source, and at least 62 magnetic poles are required. Through theoretical calculations, finite element calculations, and experimental measurements to mutually verify the magnetic induction intensity data at different distances, the results show that the designed magnetic short section can obtain good magnetic induction intensity at 120 m, which can meet the practical needs of difficult-to-drill formations, and provide theoretical and data support for the design of magnetically guided downhole magnetic source.