PR-652-195104-R02 Development of Heavy Wall ILI Test Samples

Guidance is needed for the pipeline industry’s in-line inspection (ILI) technologies as current industry practices address mainly thin-wall pipe specifications as well as spool and defect design. Heavy-wall pipe is mostly found in subsea applications where the predominant threats are internal; however, external defects cannot be discounted. Nondestructive evaluation (NDE) sensing technologies for heavy-wall pipe often have very different specifications for examining external versus internal defects.

The end uses for ILI technologies in the heavy-wall subsea applications often put a premium on low limits of detection for purposes of gauging time-dependent growth of internal wall loss rather than for fitness for service assessments. The test samples associated with the current study considers both. Post run ILI performance verification via external NDE, as is often employed for onshore applications, is prohibitively expensive for offshore applications. Thus, a high confidence in the ILI tool performance is required prior to run execution. This often drives project specific ILI performance testing and verification via an onshore pull testing as described herein. The seven categories from the Pipeline Operators Forum (POF), with an emphasis on external integrity condition performance, do not address the reasons pipeline operators may require project-specific, large-scale testing in advance of deployment. PRCI commissioned the SPIM-1-6 project to provide guidance on the design of ILI test samples for both training and blind validation purposes. It is envisioned that a standardized design process will lead to resource sharing between operators and ILI providers.