Technology Application of Borehole Magnetic Gradient Method on Deeply Buried Ferromagnetic Pipeline Detection

It is difficult to accurately detect the plane position and buried depth of deeply buried ferromagnetic pipelines by conventional geophysical methods. The plane position and buried depth of the parallel pipelines across the river are detected by borehole magnetic gradient method and borehole penetration. The results showed that the magnetic curves at different positions from the pipeline presented different characteristics with the change in distance, which verified the effectiveness and accuracy of the borehole magnetic gradient method in detecting deeply buried ferromagnetic pipelines. However, other detection methods are needed to improve the detection efficiency. The magnetic anomaly response of pipelines with different diameters in the same detection position and the magnetic anomaly range of the instrument are analyzed, which provides reference for the rapid and accurate detection of ferromagnetic pipelines with different diameters.