Pipeline threats can generally be grouped into three main categories: geometry, metal loss and cracking. Geometry and metal loss threats seem to be the most addressed, with their severity changing over time and becoming more and more obvious. Cracking threats, however, can easily be overlooked – especially tiny hairline cracks that are only millimeters in size, yet pose a much higher risk to pipeline integrity.
Addressing all three threat groups well means using a broad range of technologies to obtain an in-depth understanding of a pipeline’s current integrity status – all to ensure the data collected allows for the best integrity management decisions, now and in the future.
ROSEN Canada and Énergir have partnered on various projects since 2016. These have mostly consisted of services that utilize corrosion or geometry technologies, focused predominantly on smaller diameter, 8” to 12” pipelines. The most recent project with Énergir included inspections on two 16” sections of pipe located in Quebec, Canada, utilizing a wide array of technologies. Rather than choosing a new vendor, the way forward meant expanding within the ROSEN portfolio.
The almost 40-year-old pipeline had two previous inspections done in the 2000s and 2010s. However, with a long list of potential threats needing to be addressed – anything from metal loss and geometry to long-seam cracking and coating disbondment – the integrity status was in need of an update. The pipeline segments in question included two sections of a 16” gas line – one 93.1 km in length (from Mekinac to Bostannais) and the other 65.3 km (from St. Maurice to Mekinac), for a total of 158.4 km of pipeline to be inspected.
WHEN YOU NEED IT ALL
The project began in Trois Rivières, Quebec, with an incrementally more aggressive cleaning program. This cleaning approach was deemed necessary to ensure the more sensitive in-line inspection technologies to follow would be able to collect the best possible data and deliver an accurate integrity status.
This cleaning program consisted of running the following series of more and more aggressive cleaning tools in each pipeline section:
- Dual-body disc lamella brush tool
- Dual-body descaling disc lamella brush tool
- Heavy-duty cleaning tool with umbrella cup pull unit.
Once the pipeline had been deemed clean, the long list of potential integrity threats that Énergir wanted to monitor in these pipelines could be addressed. These included general corrosion, circumferential grooving, dents, pitting, axial grooving, mill defects and mechanical damage. Additional integrity threats from Stress Corrosion Cracking (SCC), cracking in the long seam and the degradation of the coating system two-layer extruded polyethylene) were also considered.
To ensure all of these potential threats could be managed properly, ROSEN employed an extensive series of technologies. Kicking off things was axial Magnetic Flux Leakage combined with XT technology, a combination of mechanical calipers with an electronic measurement system based on the eddy current principle. This specific combination of technologies provides insights regarding metal loss anomalies such as corrosion, erosion and gauging while measuring the depth and contour of any geometric features. Next up was circumferential MFL technology. Different from MFL-A technology, MFL-C circumferentially magnetizes the pipe to detect axial features. This makes it suitable for detecting and sizing narrow corrosion, channeling and preferential seam weld corrosion. The final technology needed to complete data collection on all possible features was EMAT-C. This technology is best used for the detection and sizing of axial crack anomalies and coating disbondment. In addition to “seeing” some general corrosion features, the MFL-C data also supports EMAT-C data analysis, thus increasing POI of crack features. After each MFL run, pipeline cleanliness was assessed based on the tool condition, the amount of debris found in the receiver trap and lift-off data, ensuring the success of the more sensitive EMAT-C inspection.
Table 1 – Why use this technology for this project?
Simply collecting data is not generally enough to fully understand the integrity status of any pipeline. Therefore, in this case, ROSEN also deployed their Crack Management Framework to ensure that the understanding of the cracking and coating threat was embedded into data analysis activities. This framework is a consolidation of current industry best practices and the most advanced pipeline crack inspection solutions with the knowledge of subject-matter experts. It outlines all the key elements needed to develop a comprehensive and justifiable crack management program. It is a systematic, collaborative approach effective for managing even the most challenging forms of cracking.
Being able to use this vast combination of technologies, all threats were appropriately considered, and ROSEN continues to support Énergir in their integrity management plan.
Typically, the ILI tools would return to their “home base” at the main ROSEN Canada facility in Calgary, Alberta, after each run to be cleaned and rebuilt with the appropriate tool combinations prior to the next run in the program. However, this process could take six to eight weeks, and transporting tools back and forth is extremely costly.
Therefore, in order to reduce this time and cost, ROSEN was able to send a number of specialized maintenance technicians to the site in Quebec. The technicians were able to complete the necessary cleaning and tool adjustment at the local Énergir workshop, completing the entire campaign in just one month.
Figure 2 – On site in Quebec