An in-line inspection (ILI) report provides the following details about a pipeline feature:
- Length and number of pipe in which the feature exists, and length of pipes in the vicinity;
- Internal or external dimension of the feature – length, width and maximum depth of the feature (box), along with its B-scan and C-scan;
- Orientation of the feature, also known as the ‘o’clock position’ of the feature;
- Distance of the feature (box) from upstream weld; and,
- Distance of the feature (box) from downstream weld.
Once these details have been logged, the pipeline is then geographically located using an XYZ ILI tool, which maps pipe circumferential welds against their ‘northing and easting’ log distance. However, these readings have errors in them and therefore take one to the general vicinity of the feature but do not confirm the exactness of its location.