Detecting metal loss and pipeline wall thinning with a combination of Ultrasonic Testing (UT) and Magnetic Flux Leakage (MFL)

In-line inspections with Ultrasonic Testing (UT) and Magnetic Flux Leakage (MFL) have become standard for pipeline integrity management programs worldwide. UT allows direct and highly accurate measurements of two-dimensional features, notably pipeline wall thickness. In contrast, MFL provides a versatile and dependable method for determining the geometry of metal loss in pipelines. ROSEN has developed a system that combines the two technologies in the single inspection tool RoCorr·MFL/UT. While the UT unit of this tool accurately scans general wall thinning and uniformly corroded areas, the MFL component supplies detailed information on smaller anomalies such as pitting corrosion. This paper shows that since the two technologies ideally complement each other, their combination constitutes an important step forward on account of its great benefits for asset integrity programs and operational cost management.