Allseas’ Pioneering Spirit deployed its revolutionary jacket lift system for the first time on 21 April to remove CNR International’s Ninian Northern jacket from the northern North Sea. At 8100 tonnes, this first commercial lift is one of the heaviest offshore jacket lifts ever, but remains well within the system’s 20,000-tonne single-lift capacity.
The world’s largest and most versatile offshore construction vessel has since arrived at the deep-water port of Lerwick, in the Shetland Islands, where the jacket will be delivered intact to the Veolia-Peterson yard for recycling. The facility targets 98 per cent steel reuse.
Pioneering Spirit arrived in the Ninian field, 160 km northeast of the Shetland Islands, on 14 April. After final preparations including cuts through the eight legs, the jacket lift system (JLS) was engaged to lift the jacket safely out of the water.
Main hoist blocks suspended from the JLS beams were attached to the jacket top by means of bespoke rigging (built by Allseas Fabrication) and, after final cuts, the 85-metre structure lifted safely out of the water. The jacket was subsequently aligned with the beams and lowered onto the main aft deck for transit to the Shetlands.
Thursday’s lift concludes two years of planning and design, which started with the safe and successful single-lift removal of the 14,200 t Ninian Northern platform topsides by Pioneering Spirit in 2020.
See the operation in pictures below (all pictures by Allseas).
Fundamentally different to conventional crane-lifting vessels, the aft-mounted system comprises two connected 170-metre-long beams that lift and support jackets of all sizes during removal and installation operations. The system also enables the transport of jackets in a near-vertical position to safeguard structure integrity.
This advanced technology enables direct transfer of structures to and from the quayside and eliminates the need for support barges. There is no need to seafasten the jacket to the beams during transit due to the vessel’s high level of stability, significantly reducing time in the field and lowering the emissions footprint.
‘With the successful removal of the Ninian Northern jacket, Allseas has realised its long-term vision of a vessel that provides the offshore industry with a total solution for offshore work,’ says Allseas President Edward Heerema.
123,000 tonnes of structures planned for 2022
Ninian Northern is the first of several major jacket removal and installation commitments for Pioneering Spirit in 2022. The vessel will lift and transport more than 123,000 tonnes of structures for the offshore energy industry this year utilising both its Jacket lift and motion-compensated Topsides lift systems.
Allseas‘ Pioneering Spirit is the largest vessel in the world and capable of lifting and transporting entire platform topsides of up to 48,000 tonnes in one piece using motion-compensated single-lift technology. The twin-hulled vessel is 382 metres long and 124 metres wide.