Post in-line inspection (ILI) digs are essential tools in the integrity arsenal to help validate and verify ILI tool performance and provide additional data, which can be input into post-ILI integrity assessments. In addition to supporting ILI, digs also have standalone benefits. Dig verification can be utilized to validate material properties, increase confidence in feature characterization or even replace previously lost records vital for assessing the integrity of features identified by ILI.
Historically, to either fully characterize ILI features and/or verify line pipe material properties, the only viable option was to destructively remove sections for destructive testing/examination. This had obvious disadvantages; however, as technology has developed, more advanced non-destructive methods have become available. These can provide accurate data without having to remove affected sections.
Recently a number of new technologies have become available for NDT sizing and characterization of features, including PAUT, TFM, XCT and laser scanning. There are also various technologies that can characterize unknown line pipe material properties, such as Instrumented Indentation Technology (IIT). An unfortunate consequence of this proliferation of new technologies is that they often require the expertise of a number of different 3rd parties. This can lead to organizational challenges and even multiple dig campaigns.
This paper reviews a number of new and emerging technologies, as well as established techniques for the in-field, non-destructive characterization of ILI features and line pipe material property verification, and it analyses the benefits and potential limitations in using them. In addition, the paper also looks at current ROSEN in-field processes, which allow for full ILI indication verification and material property verification to be performed at the same time, by the same team of technicians.