In a nutshell:
Every in-line pipeline inspection is a complex project, and the coming together of various pieces is vital for success. First-run success, as we call it, becomes more vital in certain inspections for various reasons, one of them being product demand. This was the case in the Vung Tau area of Vietnam with the inspection of a high-risk, multi-phase pipeline crucial to the import and export of product from and to an onshore terminal and for the supply of gas and condensate throughout the country. The 26-inch pipeline (371 kilometers in length) was also home to a unique WYE piece that would require some attention as it resulted in product to be transported even faster than the already high 5m/s flow rate. As is so often the case, simple data collection is not enough; what matters is what you do with the data. The ultimate goal was to provide a geometry profile of the line, conduct a dent strain analysis and gain insight into any wall loss.
Before the inspection process could even begin, complete ATEX documentation, review of experience lists and various other safety precautions had to be taken by both ROSEN and the operator because the pipeline also crossed an explosive environment. Once these securities had been assured, the project could continue. Given the need for a certain first-run success and the idea that the cleaner the pipeline, the higher the probability of a successful in-line inspection run, the cleaning tool was tailored to ensure passage through the WYE piece. For additional confidence, this set up was validated with pull tests at the ROSEN Technology and Research Center in Lingen, Germany.
After cleanliness of the line had been ensured, the ROSEN group continued with the collection of data for geometry and metal loss assessments. With this in mind, a targeted technology selection was made, and the process began with a geometry inspection – specifically an inspection dedicated to the mapping and sizing of the internal diameter and a strain analysis study using XT measurement technology. This technology is a combination of mechanical caliper measurements with eddy current proximity sensors. This technology collected the data required for the geometry profile and the dent strain analysis.
With the knowledge gained from the geometry inspection and the information that the production speed of the pipeline was faster (approximately 5 m/s) than the ideal inspection speed, the set up for the metal loss detection and sizing tool could be made. The trusty companion, axial magnetic flux leakage (MFL-A) with an additional speed control unit, would provide the results. Prior to the inspection, using 3D finite modeling calculations, the bypass of product can be pre-set, and the speed control unit, equipped with an active valve, can achieve slowed down and smooth run conditions. This allowed for the tool to travel at 1 m/s and the entire wall thickness to be magnetized throughout the inspection, ultimately resulting in high-quality data collection.
In conclusion, from optimizing cleaning performance to ideal technology selection – in only 6 days – the operator gained valuable insights into the status of the pipeline, allowing for further integrity management activities. With the data collected, the ROSEN Group was able to deliver a corrosion growth assessment, a detailed geometry profile, a dent strain analysis and a wall loss percentage measurement. In addition, any dangers were mitigated through detailed ATEX certifications, thus minimizing risk and instilling confidence in the procedure.