More than 20 years after its discovery and five years since Statoil pushed the development button, the Norwegian North Sea Gjoa field will soon begin production.
The prize is some 82million barrels of oil and condensate plus 1.4trillion cu ft of natural gas, and it will have cost some 30billion NKr (£3.1billion at current exchange rates, but less than that in reality) to access.
Of this sum, the platform has consumed some 8billion NKr (£830million), based on the contract awarded to Aker Kvaerner (now Aker Solutions) in late-2006.
The semi-submersible structure left the fjord at Stord on June 13 and is now tethered in the field on Norwegian Continental Shelf blocks 35/9 and 36/7.
According to Statoil, getting the platform finished has not been easy.
The unusually long and snow-laden winter of a few months ago created a number of challenges for the project. And when spring finally arrived, the platform tow had to be postponed.
Also, a systematic review revealed that some minor modifications had to be carried out to the hull, so Gjoa had to remain in dock for an extended period.
“We have tackled a number of unforeseen hitches on the Gjoa project. So far, we have solved all the challenges without delaying the planned start-up in the fourth quarter of 2010,” said Statoil’s vice-president for the Gjoa field development, Kjetel Digre.
“This says a lot about what our project people are made of, and it also speaks volumes about the need for having access to a competent specialist network, both in Statoil and at our suppliers.”
Some 70% of the work went to Norwegian companies, although the hull of the floater was built on sub-contract in South Korea by Samsung and then towed to Norway for mating with its deck at Stord.
Gjoa will be the first floating platform to be supplied with electricity from shore. Statoil claims this will reduce environmental emissions equivalent to those from 100,000 passenger cars.
Gjoa ranks as one of the largest ongoing field development projects in the North Sea. Aker Solutions designed, engineered and part-fabricated the platform.
Though the hull was built in the Far East, the topsides were built at the group’s Stord yard. All told, the platform has a topsides weight of 22,000 tonnes and a hull dry weight of 15,000 tonnes. Its deck measures 110m (361ft) by 85m (279ft) and therefore covers an area larger than a football field.
Aker Solutions said that more than 500 engineers located in Oslo and Mumbai designed the platform. Peak manning during the construction phase was 3,000, mostly tradesmen.
Installation of the mooring system, transportation and installation of the Gjoa platform was carried out by subsidiary Aker Marine Contractors.
Gjoa will be produced via a suite of subsea wells linked to the platform through five templates and an array of umbilicals that are being installed by Technip. FMC won the contract to provide 14 subsea wellhead trees, five templates with manifolds, a topsides control system and workover systems.
The rig, Transocean Searcher, started drilling the first of 13 wells (nine oil and four gas) during summer 2009. Transocean holds an option to drill a further three wells. The field has two satellites, named Vega and Vega South, which are being developed as subsea tie-ins to the mother field.
Gjoa and Vega gas production will be exported via a 130km (81-mile), 28in pipeline to the FLAGS pipeline system, which landfalls at St Fergus in the Scottish north-east. Oil will travel to the Mongstad refinery in Norway through Troll field infrastructure.
GDF Suez will assume operatorship at production start-up.