A Case Study How Reduced Uncertainties of Latest Enhancements in Ultrasonic Wall Measurement ILI Technology Benefit Engineering Criticality Assessments
Proceedings Publication Date
A case study is presented by which the operational inspection results demonstrate the added value of a pitting versus standard resolution inspection from an operator perspective, e.g. the aspects of reduced non-needed repairs and finding the “unknowns” are addressed. The increased precision and reliability of data are identified as key for the selection of higher resolution tools. The high scanning rates achieved in both the axial, and circumferential, directions of the pipeline is providing the enhanced information needed particularly for the presence of smaller shaped, but critical defects. These enhancements have then enabled a basis for accurate corrosion rate estimation and life-time predictions of a pipeline. With quantitatively improved data it is possible for the operator to allocate effort and financial resources more efficiently. Wall measurement inline inspection of pipelines that uses liquid-coupled ultrasonic technology, has been established and run for more than 25 years. The technique is based on pulse echo signals providing the advantage of a quantitative measurement of the wall thickness with a standard reporting accuracy around +/- 0.5mm. The latest enhancements have enabled more reliable detection and more accurate reporting with smaller sizing tolerances, though the true value rests with what the integrity engineering specialists are able to do with the enhanced information. This paper describes how the inline inspection Wall Measurement (WM) uncertainties influence the engineering criticality assessment. Moreover the development of a high resolution WM tool and its benefits of supporting a more accurate integrity assessment are covered.