Constructing the C topside

By Ole Jone Eide

The start of construction in the plate workshop at Aker Stord in October 1986 marked the beginning of bustling activity at the yard in Leirvik. Much was similar to the Gullfaks A topside that had been built at the same location a few years earlier, but there were also important differences.

— Module lift on Gullfaks C, March 1988. Photo: Øyvind Hagen/Equinor

On 5 October 1986, Aker Stord gradually began construction of the Gullfaks C topside. In February the following year, work started in the dock. The years 1986, 1987 and 1988 were marked by the construction of the C topside including all the associated modules. The work was carried out in several places around the country, before everything was finally assembled at Stord.

At roughly the same time that Aker Stord received the main contract for the Gullfaks C topside, the yard was awarded a similar assignment for Oseberg A. This triggered a very hectic period in the yard’s history. At peak, about 2,500 people were accommodated in the area. All conceivable conventional lodging was used, along with a large number of caravans.[REMOVE]Fotnote: Myklebust, Alf Terje (1994). “75 år på Kjøtteinen 1919–1994. Anniversary Book for Aker Stord.” Stord: Aker Stord, pp. 116–117. The yard had previously housed many contract workers as well; during the Statfjord A topside build, the figure in January 1977 reached 2,719.[REMOVE]Fotnote: Meland, Trude. “The work camps.” In: Industriminne Statfjord.
https://statfjord.industriminne.no/en/2018/04/05/the-work-camps/

Many suppliers

The Aker group was a key player in building the Gullfaks C topside. A substantial part of the module support frame (MSF) for Gullfaks C was fabricated at Aker Verdal.[REMOVE]Fotnote: Myklebust, Alf Terje (1994). “75 år på Kjøtteinen 1919–1994. Anniversary Book for Aker Stord.” Stord: Aker Stord, p. 129. That yard was also responsible for the control room and power distribution modules. Aker Engineering handled engineering for both the MSF and the individual modules. Aker Elektro carried out electrical installation on the topside and in the concrete substructure (GBS), while Aker Stord had overall responsibility for fabricating the MSF, assembling the modules, mating the topside to the substructure, and offshore hook‑up and completion (HUC).[REMOVE]Fotnote: Norsk oljerevy / Norwegian Oil Review. 1990, Vol. 16, No. 4, p. 31.

Leirvik Sveis delivered the living quarters (LQ), as they also had for the two other Gullfaks platforms and all the Statfjord platforms. [REMOVE]Fotnote: Resser, Tor (2001). “Byen Stord.” Stord: Eige forlag, p. 89.The company received the assignment just before Christmas 1985, and the contract was worth NOK 344 million. As at Aker Stord, this led to an extremely labor‑intensive period, since in addition to Gullfaks C they also had work on Gullfaks B and Oseberg A. The company also built the substructure for Gullfaks C’s helideck, including stairs/elevator and a waiting room. The helideck itself was fabricated by Oil Industry Services (IOS) in Kristiansand.[REMOVE]Fotnote: Myklebust, A., Leirvik sveis. (1996). “Leirvik sveis 50: Anniversary Book for Leirvik sveis.” Stord: [Leirvik sveis], pp. 123 and 194.

Modules for the living quarters are lifted into place at Aker Stord in March 1988. Photo: Øyvind Hagen/Equinor

Other suppliers included Kværner Bruk, which delivered the gas turbine package and the compressor module; Kristiansand Mekaniske Verksted built the water‑injection and process support module; Vindholmen Offshore handled the
modules for the drilling derrick, pipe rack and office; and Moss Fredrikstad Verksted fabricated the gas treatment module. Foreign suppliers included Italy’s Belleli, which provided wellhead modules, and the Netherlands’ Grootint, which built the separation module. In addition to the major suppliers, the Gullfaks C project sourced equipment and deliveries from many other companies worldwide.

How similar to the A topside?

The Gullfaks A and C topsides are in most respects alike (see article on the A topside). That yielded considerable savings, from calculations and drawings through to practical fabrication. There are, however, some key differences: Gullfaks C stands in deeper water and has longer shafts than A, which increases hydrodynamic loads from currents and waves on the structure. As a result, an extra 3,000 tonnes of steel went into strengthening the MSF. The MSF was also three metres wider and two metres longer than on the A topside.[REMOVE]Fotnote: “Gullfaks C to Aker Stord” (no author) (12 September 1986). In:
Sunnhordland, 12 September 1986.

A consequence of the similarity to the A topside was that the man‑hours needed to build the C topside fell significantly. Thanks to the experience gained from the previous project, fewer people from Statoil [now Equinor] followed the process at Stord.[REMOVE]Fotnote: Hansen, Thorvald Buch et al. (1990). “Gullfaks – Glimpses from the
History of a Fully Norwegian Oil Field.” Stavanger: Statoil, pp. 113–114. A central objective was to complete as much as possible onshore; work offshore on the continental shelf carries far higher costs and increased safety risk.

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The table below shows who built many of the key modules for the Gullfaks C topside. See also the table at the end for a comparison with Gullfaks A. The
lists are not exhaustive.[REMOVE]Fotnote: The tables were prepared by Ole Kvadsheim.