At the Pipeline Pigging Integrity Management Conference, some of Kiefner’s specialists will be giving a lecture on the following topic:
Validating ILI Accuracy Using Spatial in-ditch Scanning Measurements
by Harvey Haines, Lucinda Smart, and Ben Wright, Kiefner & Associates, Inc., USA
This paper looks at using spatially recorded metal-loss data collected in-the-ditch to measure the accuracy of ILI tool results. Spatially-mapped metal loss, because all of the corrosion area is mapped, has the advantage of allowing more comparisons to be made for a given corrosion area which can allow many more corrosion pits to be compared, yielding a larger sample set for a minimum number of excavations; it also allows the interaction among corrosion pits to be studied for examining burst pressure calculation accuracy. From our studies we find the depth error for shallow corrosion 10%-20% wt deep is often not representative of deeper corrsion in the same pipeline, and the interaction criteria for ILI tools needs to be larger than the interaction criteria for in-ditch data. Examples are shown where certain ILI runs require no excavations and others may require additional excavations than suggested by normal ILI data.
