Statfjord A loading buoy towed out

By Finn Harald Sandberg, Norwegian Petroleum Museum

The loading buoy for Statfjord A was towed out and moored on the field in August 1978, following its launch at the Kværner Brug Egersund yard south of Stavanger that May.

— Illustration: Jan Ø. Ulriksen

This structure ranked as the largest articulate loading platform (ALP) in the world. It stood 190 metres high in all, weighed some 5 000 tonnes, and had a loading capacity of 600 000 barrels per hour.

Although Kværner had been main contractor for the buoy, and fabricated the 130-metre-long, 3 800-tonne column, foreign companies were also involved in the project. Its base section was built in France by Compagnie Francaise d’Entreprises et Metalliques (CFEM) and Equipmemts Mechanies et Hydraulics (EMH) for mating with the column in Egersund.

From there, it was skidded onto a barge and towed into the harbour basin. The vessel was then submerged so that the buoy floated free. It was raised to an upright position and towed to the Åmøy Fjord for mating with the topside – also built by Kværner.
The latter was a rotating unit standing 15 metres high and weighing 530 tonnes, topped with a 25-metre-diameter helideck plus safety nets. It had also been skidded onto a barge and towed to the mating site.

A great deal of expensive equipment was mounted on the buoy, including a set of three generators, each producing 50 kilowatts, to supply it with power.

Although the buoy would be unstaffed, it had the facilities for people to stay on board in order to conduct repair or maintenance work. There was one four-berth cabin, a kitchen, a toilet and a shower.

The structure reached the field in mid-August 1978 after being towed from Stavanger by two tugs, which started on 9 August. The voyage took longer than expected because of difficult currents, and lasted five days at an average speed of just under two knots. Small Zodiac-type boats with outboard motors were used to assist during installation, which required both wind and waves to be favourable.

The foundation for the buoy and the flowline connecting it with Statfjord A had been installed on the field 14 months earlier.

Learn more: Statfjord Loading buoys

Sources
Hæreid, Jan-Erik. Project planning – an Analysis of the Statfjord A Project. Trondheim 1980, p 44.
Operating manual, Statfjord A articulated loading platform, volume I, 1.2.3 and 1.4.5.
Stavanger Aftenblad, weeks 47-49 and 27 May 1978.