Some methods of enhancing oil-gas pipeline magnetic flux leakage (MFL) detection
technique are introduced in the paper. Some man-made defects or imperfections on the pipe surface
are detected via the axial magnetization inspection vehicle along the pipeline. The magnetic dipole
model of corrosion defect is stated and the important interference factors on magnetic flux leakage are
analyzed. Finite element method is used to analyze and simulate normal defects on pipe surface,
which can attribute to get natural defect MFL signal. The influence of benign pipeline artifacts
(valves, welds, tees, flanges, etc.), pipe material and pipe wall, vehicle velocity, defect dimensions
and interaction among defects, and so on are studied in detail. The magnetic flux leakage contour
images or indication extraction maps are given and presented. These interference factors are
compensated and solved. These approaches and results applied in the paper are contributed to the
feature extraction and indication of pipeline abnormality. The results suggest that these approaches
and conclusions are significantly effective for the pipeline magnetic flux leakage inspection.
The axial crack testing model for long distance oil-gas pipeline based on magnetic flux leakage internal inspection method