Research on Unsaturated Magnetization MFL Detection of Gouge in Oil and Gas Pipeline

Abstract

AbstractOil and gas pipeline online detection technology can effectively detect metal loss defects, but the ability to identify mechanical damage gouge is limited. Given the shortcomings of the existing pipeline inspection technology, a DC magnetic yoke unsaturated magnetic flux leakage detection technology is proposed. The transient mechanics three-dimensional finite element model of the gouge site of the pipeline mechanical damage is established and the simulation results show that the obvious compressive stress is generated in the gouge part of the pipeline. A test device for unsaturated magnetic flux leakage detection is set up, and an experiment of gouge of oil and gas pipelines under unsaturated magnetization is carried out. The results show that the amplitude and peak-to-peak value of the MFL signal are affected by the stress at the defect region, which is very different from the leakage magnetic field signal of gouge without stress. Unsaturated magnetic flux leakage detection technology can not only effectively detect gouge defects, but also realize the identification and differentiation of them. The research results provide technical support for the application of unsaturated magnetic flux leakage detection technology in the detection and identification of oil and gas pipeline mechanical damage gouge.