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Pipeline replacement under challenging conditions

  • 4.5-kilometre pipeline
  • 300,000 cubic metres sand removed
  • 7 metres tidal difference

Operating in vulnerable environments or at remote locations is what inspires Van Oord’s engineers to come up with innovative solutions. The Tetney Sealine project has both: the project site was inaccessible by land and minimal environmental impact had to be ensured. In other words, replacing a 40-year-old pipeline under these conditions required a project team full of ingenious people.

Marine ingenuity puzzle

Energy supplier and logistics company Phillips 66 contracted Van Oord to replace the pipeline that connected the Humber oil refinery in North Lincolnshire, to the Single Point Mooring buoy (SPM buoy)  in the North Sea. The pipeline had to be replaced to guarantee the safe transport of oil. Joep Athmer, Managing Director of Van Oord Offshore: ‘Most of it was installed under water, but we were also responsible for landfall on the beach and for connecting the new pipeline to the current onshore pipeline. Because the project site was inaccessible by land, the execution was a true Marine ingenuity puzzle.’

Logistical challenge

Normally, the new sections of the pipeline – the strings – would have been delivered to the site over land. But this project site adjoins an area that is off-limits to our client, so the only option was to transport the strings over water. In fact, everything had to be transported over water, even the earthmoving equipment and the employees. In other words, the situation presented a true logistical challenge! The pipes were transported to Britain on a giant pontoon. During spring tide, this pontoon was positioned carefully on the beach near the project site. A walkway allowed everyone to move between the pontoons safely. 

This is an exciting and challenging project that has been in the planning for more than four years. The team has been working extremely hard to ensure that the pipeline replacement was uneventful and, most importantly, safe.

Clive Hitchman, Technical Manager, Humber Refinery

Care for flora and fauna

The set-up with pontoons on the beach also minimised impact to the surrounding area. Local infrastructure was not affected by the works. In order to ensure minimal environmental impact, Phillips 66 worked in partnership with a number of stakeholders, including the Royal Society for the Protection of Birds, the Environment Agency, and Natural England. Photographs had been taken of the beach and a topography survey carried out to measure the height and depth before our activities commenced. In this way we could ensure it would be restored to its natural state once the project was completed. 

Ready for the future

To execute the pipeline replacement, the refinery was taken off-line for more than two months: from early May until mid-July 2015. After the SPM buoy was overhauled by the client, it was returned to its original location. Everything was reconnected, and the pipeline was buried on the beach. Finally, trailing suction hopper dredger backfilled the trench, so that the new pipeline lays in a stable and protected position on the seabed. Back in operation, the pipeline is ready to face the next 40 years!

We can thank our good relationship with Phillips 66 and our inventiveness for this project. The remote project location and tight schedule made the Tetney project in England a real logistical challenge.

Hans Bekendam, Regional Manager North Sea & Europe for Offshore
Additional information
  • Start date
    31 October 2014
  • End date
    31 July 2015
  • Location
    North Lincolnshire, United Kingdom
  • Business Unit
    Offshore
  • Client
    Phillips 66