Heerema’s Sleipnir, the LNG-powered world’s largest semi-submersible crane vessel, has set a record for the largest single lift jacket removal.
Heerema said on Monday that Sleipnir successfully removed the 8,100-tonne Jotun-B jacket in the Norwegian North Sea for client Vår Energi.
The platform was installed in 1998 by Heerema’s Thialf, who returned to the Jotun Field last year to remove the topsides and conductors – demonstrating the circularity of Heerema’s involvement in the lifecycle of these now retiring platforms.
For the jacket removal, Sleipnir arrived at the Jotun Field, located 200 kilometres west of Stavanger, on 11 July. It completed the project by offloading the jacket onto the quayside at the AF Miljøbase decommissioning site in Vats, Norway, on 16 July. The jacket will end its lifecycle by being recycled up to 99 per cent.
It is worth noting that the entire removal scope in the Jotun field was completed in only four days.
During this project, skirt piles – with diameters 2.7 metres and 80 millimetres of wall thickness – were cut subsea, the largest ever done in this way. Also, Heerema fabricated a 40-metres-long spreader bar.
Sleipnir performed the full removal operations while running on emission-reducing LNG fuel. By using LNG, the vessel reduces CO2 emissions by 25 per cent, reduces NOx emissions by 92 per cent, SOx by 99 per cent, and particulate materials by <99 per cent compared to traditional marine gas oil crane vessels.
Heerema’s 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”.