Statfjord A leaves the dry dock

by Trude Meland, Norwegian Petroleum Museum

Norwegian Contractors (NC) had secured a lease from the City of Stavanger to use the Hinnavågen site and mooring points in the Gands Fjord.

— The GBS is towed into the Gandsfjord for further slip casting of the shafts. Photo: Unknown/Norwegian Petroleum Museum

It filled in the Hinna bay to create a dry dock and installed warehousing and a work camp on the adjacent fields.[REMOVE]Fotnote: Stangeland, P. (1977). Condeep : En arbeidsplass i Stavanger (Vol. 1/77, Rapport (Rogalandsforskning : trykt utg.)). Stavanger: Rogalandsforskning: 157.

The base section of the Statfjord A gravity base structure (GBS) was cast in this facility. Before concrete work could start, however, a steel “skirt” had to be installed where each cell would stand, so that the GBS would dig down into the seabed and ensure the stability of the platform. Nineteen concrete cells were then constructed to a height of 14 metres on top of the skirts.

Once that work had been completed, the dock was filled with water so that the structure floated and could be towed out to the fjord. It was moored about a kilometre from land. From then on, all equipment and personnel had to be ferried out and in by boat.

Fifteen of the cells were intended to store crude oil, one would serve as a storage tank for diesel oil to run machinery on the platform, and the final three cells were extended upwards as shafts to support the topside.

Casting of the cells in the Hinnavågen dock was completed without problems or delays, and the base section could be towed out into the Gands Fjord in May 1975 for continued slipforming of cells and shafts.

To learn more about why the choice fell on such a large and heavy structure as the Condeep, why it was built in Stavanger, what slipforming actually involves, how the work was done, and the challenges and working environment involved.

see the article: Building the Statfjord A GBS.

Notes:
[1] Stangeland, Per. Condeep. En arbeidsplass i Stavanger. Rogaland Research, report no 1 1977, p 157.