Improvement Effect of Active Magnetization on Subsea Pipeline Localization

Abstract

Accurate localization of subsea pipelines is the prerequisite for its inspection, reinforcement and maintenance. Magnetic anomaly generated by the ferromagnetic pipeline immersed in the earth’s magnetic field can be used to locate the pipeline. However, since the magnetic field decays rapidly with distance, the detection distance is very limited. This paper proposes a method to improve the sensitivity and limit distance of pipeline detection and positioning through active magnetization. When the magnet is directly above the pipe, the magnetization effect is best, so a magnet array should be used to cover the pipe with wide enough coverage. Experiments have proved that by using a magnet array, with SNR = 20 dB as the judging criterion, the limit detection distance of a Φ219mm steel pipe can be increased from 0.363m to 0.554m.