Sheffield Forgemasters goes large with record breaking contract win
Sheffield Forgemasters’ specialist offshore design and engineering division, has announced a triple record-breaking contract win.
The contract, on behalf of Hyundai and Technip is the largest won by Sheffield Forgemasters. It will see delivery of the largest cast steel nodes ever made, for the world’s largest floating Spar gas production platform– the first of its type to operate in the Norwegian Sea.
Sheffield Forgemasters will deliver 12 ultra-large castings for the Spar, operated by Statoil ASA on behalf of the partners OMV, ConocoPhillips and Statoil, which will see service in the deep water Aasta Hansteen field off the coast of Norway.
Paul Mockford, design director at Sheffield Forgemasters, said: “The project to develop the Aasta Hansteen gas field requires the world’s largest Spar platform.”
The castings will form high strength and fatigue resistant nodal joints to connect the main leg and brace tubulars which make up the lower, truss section of the Spar platform.
Paul added: “The Aasta Hansteen Spar is the largest diameter Spar which has ever been built with a diameter of 50 metres and a total hull length of 198 meters, most of which is below the surface of the sea.
“With water depths of more than 4,200 feet this is a deep water application and floating platforms are the only real option at these depths.”
Technip is acknowledged as the world leader in the manufacture of Spars, and in particular, truss Spars. The platform will sit vertically in the water, with its cylindrical hull providing buoyancy and stability, and tethered by mooring lines connected to piles in the sea bed.
Sheffield Forgemasters will design and supply 12 cast nodes, the largest of which weigh 117 tonnes, seven tonnes heavier than the largest nodes made to date.
Paul continued: “The castings will be made in a specially developed and proven grade of steel offering a balance of strength, toughness and weldability. The strength is developed through heat treatment involving water quenching and these are the biggest castings we have ever quenched.
“Like all the cast nodes we have designed and supplied over the past 30 years, these castings will need to withstand immense stresses when in use. Sheffield Forgemasters has a unique track record in the supply of this type of component.”
Total recoverable reserves for Aasta Hansteen, previously called Luva, are estimated at about 47 billion standard cubic metres (scm) of gas and 0.9 million scm of condensate.
The platform, which will be located approximately 186 miles off the Norwegian coast will be the first Spar platform built with storage capacity. It will be able to store about 25,000 scm of condensate, and export gas via the Polarled pipeline to Norway’s Nyhamna gas plant.
Sheffield Forgemasters’s involvement in the project is expected to run through until March 2014.