In-line inspection of oil pipeline network by TDW

T.D. Williamson has recently carried out an in-line inspection of a key oil pipeline network that runs through Parentis Lake, a popular leisure destination nestled among pine forests in southwest France.

The inspection programme was carried out on 12 oil production lines and one oil transmission line near Bordeaux, and was the first time T.D. Williamson (TDW) supplied this service to Vermilion REP, a division of Canadian energy firm Vermilion Energy.

Parentis Lake is dotted with numerous oil platforms that Vermilion uses to extract oil from wells, down to 2.4 km. The lines connect with the platforms on the lake and transport the extracted material, an oil and water mix, to the treatment stations in Parentis. The oil is then transported to a storage area in Ambès, from where it is delivered to refineries throughout France.

Custom solution protects lake and wildlife

As Parentis Lake is an environmentally-sensitive location, all aspects of the operation had to comply with Direction Régionale de l’Environnement de l’Aménagement et du Logement, France’s strict environmental legislation. To ensure that the operation would conform to the stringent regulations, Vermilion retained TDW to assess the corrosion levels of its 4 inch, 6 inch, and 8 inch oil production lines, using a magnetic-flux leakage (MFL) in-line inspection tool.

Because portions of the pipelines are located below lake level, a complex series of bypasses were installed to interconnect the lines and ensure that longer inspection runs, of up to 10 km, were feasible. Work had to be performed from the production platforms, where temporary launchers and receivers were installed, as well as on tankers used to collect residual from the pig traps. Distributed throughout the lake, the lines scheduled for inspection ranged in length from 400 m up to 11.2 km. This configuration required TDW to continually transport materials and technicians by barge between the production platforms, and the logistics for this operation required meticulous advance planning and attention to detail by TDW and Vermilion project managers, as well as by boat fleet personnel.

Record runs

To ensure that the MFL tool would be capable of travelling through the various pipeline bends, TDW technicians conducted cleaning and gauging operations prior to the inspection. During the operation, technicians monitored the pipeline pressure, which varied from 10 to 20 bar.

TDW performed the inspection runs at a constant speed of 0.8 m per second, preventing the tool from becoming lodged in the pipeline and ensuring that the data collected were of the highest quality. Field-data were systematically checked and validated by TDW technicians, and subsequently forwarded for analysis to TDW analysts in Swindon, UK.

TDW conducted its first MFL inspection campaign for Vermilion, on five separate lines, in a record time of six days. The operation was performed on schedule and in accordance with the very stringent environmental rules applicable to this specific site.

Following this first inspection for Vermilion in France, TDW conducted another successful inspection campaign on the remaining eight 4 inch diameter pipelines in the protected lakes and forests surrounding the Parentis Lake region. Looking ahead, TDW will inspect additional 6 and 8 inch diameter pipelines for Vermilion in the Paris Basin fields this year.

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