ALLSEAS PIONEERING SIPRIT REMOVES NINIAN NORTHERN TOPSIDES IN THE NORTH SEA
Pioneering Spirit has successfully completed her third and final decommissioning job of 2020, single-lift removal of the North Sea’s 14,200 t Ninian Northern topsides.
Just days after delivering the Tyra flare jackets to Sagro’s recycling yard in Vlissingen, the Netherlands, the world’s largest construction vessel was back north of the Shetland Islands pulling more decommissioned facilities out of the North Sea.
Completed Friday morning, 28 August, the removal operation took 2 hours, from connecting the vessel’s topsides lifting beams to the platform to the lift, ensuring environmental emissions from the removal activities were kept to a minimum with the efficient vessel systems.
Safely on board after a 7-second “fast-lift”, the former drilling and production topsides were heading to the Peterson-Veolia yard in Dales Voe, Shetland, for recycling. The facility will target over a 97% reuse/recycle ratio and create a number of jobs over the period the topsides is dismantled.
The lift concluded a busy 2020 heavy lift season, during which Pioneering Spirit removed more than 57,000 tonnes of steel – equal to 8 Eiffel Towers! – out of the North Sea’s Brent oil and Tyra gas fields, and delivered the structures to yards in Denmark, the Netherlands and the UK.
The Ninian Central Platform is an oil platform in the North Sea. When constructed in Loch Kishorn, Scotland in 1978 the 600,000 tonne platform was the world’s largest man-made movable object before being towed to its current position and sunk to the sea floor.
It is a circular concrete gravity structure, 140 m in diameter at its base, with seven concentric walls of stepped heights intersected by radial walls at 45-degree angles. A 14 m wide central shaft is surrounded by a breakwater wall, 45 m in diameter and 1.6 m thick pierced with 1.5m diameter holes. Between these two walls drill slots are arranged for drilling up to 42 wells
The Ninian field lies in United Kingdom Continental Shelf (UKCS) Blocks 3/2, 3/3, 3/7 and 3/8. The reservoir is contained in the marine-deltaic sandstones of the Middle Jurassic Brent Group. There were estimated to be 2,920 million barrels (464 million cubic metres) of oil in place of which 35 to 40 percent was thought to be recoverable. Ninian oil is a paraffinic-naphthenic type with an API gravity of 36°.
Ninian Central operates in conjunction with the Ninian Southern and Ninian Northern platforms. First oil was produced from the field in December 1978. Production reached a peak of 315,000 barrels (50,100 m3) of oil per day in the summer of 1982. At the end of 1988 over 811 million bbl (129 million m3) had been produced.[
(Source and image: Allseas)