In-Ditch Validation Methodology for Determination of Defect Sizing

Overview

Main Objective

The project will develop, improve and demonstrate a robust technology for accurate and reliable sizing of complex crack like anomalies by adopting an existing, proven technology for the purpose. Applus RTD has developed the technology over the last several years, primarily for girth weld inspection in new pipeline construction. However, the capabilities of the technology and the robustness of the tool make it ideally suited for in-ditch application for pipeline integrity. The tool's ability to discriminate closely spaced defects and accurately size cracks irrespective of their orientation make it an ideal solution for sizing complex cracks such as stress corrosion cracks and seam weld defects. Successful completion of this project would provide the industry with valuable defect measurements as well as enable a step change in the way in-line inspection data from crack tools is used.

Public Abstract

In-line inspection is one of the most efficient and effective tools for evaluating the integrity of a pipeline. Knowledge of existing defects in a pipeline, combined with robust and reliable methods to assess the defects enables pipeline operators to optimize their response while maintaining a high level of reliability and safety. Until recently, however, in-line inspection tools were not as effective in detecting and measuring cracks and crack colonies with a high level of accuracy. Furthermore, since most crack detection tools utilized ultrasonic technology, inspection of gas transmission pipelines for cracks was difficult. Recent advancements such as development of Electromagnetic Acoustic Transducer (EMAT) technology for in-line inspection, circumferential and combination MFL and further development of ultrasonic ILI tools has paved the way for effectively utilizing ILI to manage the threat of cracks and crack colonies. Every measurement tool has some inherent error, comprising of both a systematic and a random component. While these errors cannot be completely eliminated, the errors can be minimized if it can be measured and understood. Pipeline operators are able to do that by performing verification measurements using more direct examinations at excavations along the pipelines. One key requirement of doing such verifications is that the verification measurements have to be an order of magnitude more accurate than the primary inspection (ILI). For verification inspection of cracks, this is a gap in technology. Current verification technologies are either broadly applicable, but not as accurate or are accurate, but not very robust. This project aims at bridging that gap by adopting a proven technology, Inverse Wave Field Extrapolation (IWEX), which is being developed by Applus RTD for several years aimed at improving the detection and sizing of defects in pipeline girth welds during new pipeline construction. This project comprises adopting IWEX for the inspection of cracks and crack colonies in existing pipelines. The project follows from preliminary trials performed by Applus RTD on real pipeline defects as a proof of concept. The study identified that improvements need to be made to the existing hardware and software to make the technique more robust and to increase the range of applicability. The expected deliverable is a field ready prototype that utilizes the IWEX technology to provide reliable, robust and accurate means of measuring cracks in in-service pipelines.

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