In line Inspection (ILI) tools have been the primary pipelines’ inspection methodology for decades. With the increasing knowledge of identified damage mechanisms in pipelines, more ILI technologies evolved to accurately detect and size all pipeline integrity threats. The major integrity threat for carbon steel pipelines is corrosion (pitting and general corrosion). In this paper, a comparison between two most popular ILI technologies has been discussed. The first is Magnetic Flux Leakage (MFL) and the second is Ultrasonic Thickness Metal Loss (UTML) tool.

Firstly, the principle of detection technology of both MFL and UTML has been discussed for their applicability and feasibility including any limitations during pipeline operations. Secondly, identification and sizing accuracies are other important aspects to identify all susceptible damage mechanisms of the pipeline and their implications on fitness for service assessments have also been discussed. A special focus has been given to specific attributes of each technology that enables detecting important pipe features; in particular: metallic sleeves and mid wall features.

The paper has concluded with a case study of a crude pipeline was inspected by both MFL and UTML ILI technologies respectively to demonstrate the comparison on critical parameters discussed earlier and to optimize the inspection and maintenance cost.