Inspection and Identification of Inner-outer Defects on Oil-gas Pipeline

The paper discussed pipeline inner-outer defects inspection and identification methods in pipeline magnetic flux leakage (MFL) inspection. Inspection vehicle got across defects in some velocity, bringing residual MFL, its signal frequency and peak value depend on defects size, defects shape, defects in inner or outer, inspected by Hall element sensors. The results of this research indicate different character of defects MFL signal is a method of inspection and identification of inner-outer defects, improving integrity assessment of defects.