DOF Subsea Completes North Sea Decom Work For Repsol Sinopec

DOF Subsea has carried out a decommissioning project on behalf of Repsol Sinopec Resources UK at the Buchan and Hannay fields in the Central North Sea.

DOF Subsea stated that it achieved a 99 percent rate for the combined recycling and repurposing of recovered materials.

The offshore works, which were carried out over 74 days, using DOF Subsea’s Skandi Acergy and Skandi Skansen vessels, saw the recovery of 135 concrete mattresses weighing approximately 800 tons, more than 7.5 miles of rigid pipelines, SSIV/PLEM structures, some 10 miles of flexibles and umbilicals, spool pieces, and around 1,500 grout bags, and general debris.

The material was shipped to Aberdeen Harbour’s Clipper Quay for dispersal, with 95 percent of the material being recycled and 4 percent being repurposed. Only 1 percent was sent to landfills as a last resort.

A total of 15 concrete mattresses were repurposed into aggregate and used in the roads at the $460 million Aberdeen Harbour extension project. The plastic sheaths from the flexible risers and umbilicals were recycled by an approved supplier and all of the metal was smelted.

This was the second decommissioning project carried out by DOF Subsea on behalf of Repsol Sinopec in the Buchan and Hannay fields. In 2019, the company carried out the removal of the 124-ton Mid-Water Arch – among other things – which is still one of the largest structures ever decommissioned through Aberdeen Harbour.

That project also included the recovery of risers and all associated equipment, achieving a combined recycling and repurposing rate of 97.7 percent.

“This project is a demonstration of the DOF Group’s capability to use our fleet of world-class vessels to deliver turnkey solutions to the subsea energy sectors, in this instance a decommissioning scope for a key repeat customer. […] work with Repsol Sinopec [enabled] 99 percent recycling and repurposing at Buchan and Hannay,” Jan Kristian Haukeland, DOF Subsea’s EVP for the Atlantic Region, said.

“We are delighted with this outcome as part of one of our biggest subsea decommissioning projects in the North Sea to date,” Luis Batalla, Head of Decommissioning at Repsol Sinopec, stated.

“A truly collaborative and open communication approach was taken on this project between Repsol Sinopec and DOF Subsea and I do not doubt that this helped to facilitate the success and safe execution of this part of our decommissioning program. Our decommissioning strategy is focused on efficiency, performance management, innovative contracting models, technology development, and fit-for-purpose design which aligns well with DOF Subsea and their way of working,” Batalla added.

DOF Subsea claimed that this latest project confirmed its commitment to leading the way in championing environmental and social sustainability in the industry.

“Being named as one of only 300 companies in the Europe Climate Leaders Report was an important recognition for DOF Subsea on a number of levels,” said Stig Clementsen, DOF Subsea Chief Sustainability Officer. “It clearly demonstrates our leadership in reducing our GHG emissions intensity.”

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