A study of crack detection ultrasonic calls relating to the different types of cracking discovered in pipelines when using crack detection ILI

摘要

MANY PIPELINE OPERATOES today are using a risk based approach in their (IMP) Integrity Management Plans, including the susceptibility of their pipelines to have Stress Corrosion Cracking or long seam fatigue cracking issues. However, through the cumulative experience of crack inspection, we have identified more than 17 different crack morphologies found in pipelines. This distinction then ultimately leads to a next generation of crack ILI specifications, where the focus shifts from detection ( Probability of Detection = POD) to identification (Probability of Identification = POI) and quantitative sizing. The emphasis is changing from detection and sizing of cracking, to one of "what type of crack is it?", and its signifcance to pipeline integrity; including consideration of location, and whether that type of crack is growing or is benign.