Is your pipeline clean enough for in-line inspection?

摘要

Intelligent inspection plays a key role in the continuing monitoring of pipeline integrity. It is widely recognised thatnone of the main causes of the failure of such surveys is the unexpected presence of unacceptable quantities of debrisnin the line being surveyed, leading to a degradation of data quality. As a result, the design of a suitable pre-cleaningnprogramme, and the reliable assessment of its results, plays an important role in the overall success of the inspectionnprocess. However, since techniques for assessing pipeline cleanliness have remained relatively primitive, it is generallynrequired to design these pre-inspection cleaning programmes in a conservative way, for example by aiming to clean untilnsatisfied with the volume of debris produced with a pigging tool. This extends the timescale for the operation, whilennevertheless – all too frequently – failing to prevent surveys which deliver data compromised by the presence of largenquantities of debris.nRecent advances in intelligent calipering technology have resulted in improvements in the tools used to carry out thesenassessments, allowing for far greater accuracy when measuring the depth of debris present on the pipe wall. This papernlooks at the techniques currently adopted for assessing the cleanliness of pipelines and in particular describes the usenof Hall Effect based sensor technology, configured to detect proximity to the pipe wall. The paper considers how thisnhas been used in a tool with a suitable arrangement of pig mounted sensors which has the capability to measure thencircumferential profile of debris to an accuracy of +/-0.5mm.