In pipe inspection techniques are important in the ongoing maintenance of the gas transmission pipeline infrastructure. Acoustic Resonance Technology is a new type of in line inspection measurement which uses ultrasonic techniques.

The main advantage of the technique would be the ability to accurately locate features on the pipe circumferentially and accurately size any defects identified. This will be key information in understanding criticality of defects found when assessing the pipeline integrity and making effective, efficient decisions repairs and replacement.

The ultrasonic technique means there is no requirement for a liquid couplant between the measuring probe and the pipe wall. It can also cope with a large stand-off between the pipe wall and the sensor so multiple diameter pipelines can be inspected with the same sensor arrangement. This arrangement also offers advantages as it potentially requires less onerous network configurations for running inspections. In recent times changing flow patterns mean that the scheduling of ILI runs and the flow / speed control required can be problematic. A tool which can cope with higher gas flows would be advantageous.

Detection of coating disbondment is also seen as a key enhancement ART could bring. This is an area of risk particularly related to metal loss corrosion at AGI sites. Coating disbondment can lead to false cathodic protection readings and lead to rapid corrosion in localised areas. Current disbondment survey techniques are limited to EMAT. This technique remains expensive and has proven to be unreliable in evaluating disbondment. Evaluation of coating disbondment capability through ART, will, if successful provide additional information on an existing integrity risk which cannot currently be readily quantified or targeted.

Benefits