Gouge detection on dents below 1 depth with multiple data set technologies on an ILI tool

摘要

U.S.federal regulation 49 CFR192/195 requires repair of dents with depths greater than 6% of the pipeline's outer diameter, as well as any dent with metal loss.Pipeline failures have occurred from dents that pass these regulations.For example, dents with depths shallower than 3% may result in pipeline failure due to fatigue.Conversely, dents interacting with coincidental metal loss have been known to survive for extended service.Technology that records multiple data sets using a single in-line inspection device has shown capability in detecting low level mechanical damage interacting with dents less than 1%, with the results verified by dig feedback.The technology-which uses an oblique high field magnetizer, an axial high field magnetizer, an axial low field magnetizer, and a high-resolution geometry module-has also discriminated metal loss signatures indicative of gouging from corrosion and identified dents that have been re-rounded from those that are constrained.These factors are all important to integrity decisionmaking.This paper evaluates the multiple data set tool's detection and sizing accuracy against in-the-ditch NDE results.Specifically, it compares the capabilities of the tool versus NDE on dents below 1% depth with associated gouging or metal loss, and on constrained and re-rounded dents.