KOC operates several gas and liquid pipelines supplying fuel to power station. A 42”, 62 km. long Gas pipeline (FG067) was due for inspection. Earlier inspection using ultrasonic ILI tool had identified several laminations, which were repaired by cutting out and replacing with new pipes. Hence the re-inspection required to be done using ultrasonic ILI tool to identify metal loss features as well as mid-wall anomalies. Since the pipeline is in gas service, running conventional ultrasonic tools would require a liquid batch which is not possible without shutdown of the pipeline, and consequently shutdown of power station gas turbines.
NDT Systems & Services has developed a new ILI tool (3TM) combining three different technologies in a single sensor (ultrasonic, eddy current, MFL) whereby ultrasound is generated using the EMAT method. The latter allows for similar performance as conventional UT inspection and can detect - apart from metal loss - mid-wall lamination. The EMAT method does not require liquid media and can perform in Gas service. KOC entrusted inspection of 42” gas line to M/s NDT utilizing this tool. This paper describes the operational details, challenges faced and verification results.