Quantitative Study on Signal Characteristics of MFL Internal Inspection in Oil and Gas Pipelines Based on Magnetoelectric Unification

The unified theory of magnetism and electricity based on Maxwell’s equations is utilized to calculate the magnetic leakage field at the defect location of the pipeline. This establishes a quantitative equation for magnetic flux leakage (MFL) signals under magnetoelectric unification. The quantization relationship involving the dimensions of defects along with MFL signals is calculated. The variation of MFL signals for different circumferential offsets and liftoffs of the probe is calculated. The findings show that the intensity of the MFL signal increases with increasing defect depth and width, and decreases with increasing defect length. It was found that the MFL signals intensity is most sensible to the depth of the defects. The MFL signal width expands as the defect length increases, but it remains unaffected by changes in the defect’s depth and width. The conducted analyses indicate that the peak point of the axial component and the over-zero points of the radial component in MFL signals remain positioned at the defect center. The calculation accuracy under the magnetoelectric unification method is improved by 21% and 13.1%. It is found that the MFL signal intensity decays linearly and exponentially with the circumferential offset and liftoff, but the signal characteristics are not affected.