Heerema, a major marine contractor based in Leiden, the Netherlands, has broken the record for the largest single lift jacket removal.
Heerema’s semi-submersible crane vessel (SSCV) Sleipnir successfully removed the 8,100-tonne Jotun-B jacket in the Norwegian North Sea for client Vår Energi. The Jotun-B wellhead platform was installed in 1998 by Heerema’s Thialf deepwater construction vehicle (DCV), which returned last year to remove the topsides and conductors at the Jotun Field.
Sleipnir arrived at the Jotun Field, 200 km west of Stavanger, Norway on 11 July. The project was completed on Thursday, July 16 and the jacket was offloaded onto the quayside of the decommissioning site in Vats, AF Miljøbase.
The removal was completed in four days; according to Heerema this was one day ahead of schedule.
During this project, Heerema cut skirt piles with 2.7m diameters and 80mm wall thickness subsea, the largest ever done in this way. The spreaderbar fabricated by Heerema was 40m long with a 2mm tolerance.
Sleipnir performed the operation while running on LNG fuel. Heerema said that in comparison with traditional Marine Gas Oil crane vessels LNG fuel reduces CO2 emissions by 25%, NOx emissions by 92%, SOₓ emissions by 99% and particulate materials by <99%.
The Jotun-B jacket will end its lifecycle by being recycled up to 99%.
Heerema CEO Koos-Jan van Brouwershaven said: “We set records to break them, and we are proud to have worked alongside our client Vår Energi to complete the Jotun-B removal with mighty Sleipnir safely, sustainably, and in the shortest possible time.”