Statfjord was discovered by Mobil in 1974, and then Statoil, now Equinor, took over the operatorship on 1 January 1987.
The field has been developed with the Statfjord A, B and C production platforms, which all have concrete gravity base structures incorporating storage cells.
Statfjord A
Began production on 24 November 1979.
- Topside weight: 41,500 tons
- Concrete substructure weight: 200,100 tons
- Storage volume: 206,000 m3
- Total height: 270 metres
- Living quarters accommodate: 206 people.
- Production start: 24 November 1979
Followed on 5 November 1982, and Statfjord C on 26 June 1985.
The Norwegian share of the field lies in blocks 33/9 and 33/12 in production licence 037, while the British part is in UK block 211/25 in licences 104 and 293.
Statfjord is one of the oldest producing fields on the Norwegian continental shelf, and the largest oil discovery in the North Sea.
Oil and gas transport
Statfjord oil production is loaded into shuttle tankers on the field and shipped to a number of ports in north-western Europe.
The gas export, previously going via Statpipe to Kårstø, has since the startup of Statfjord Late-life in 2008 gone through Tampen Link and the FLAGS system to the St. Fergus gas terminal in Scotland.
Britain’s 14.53 per cent of the gas has since the startup of the Statfjord field travelsled by a separate pipeline via the NLGP pipeline to Scotland.
Cargoes are allocated between the field licensees in proportion to their interest in the respective licences.
RECOVERY STRATEGY
The field was originally produced by pressure support from water alternating gas injection (WAG), water injection and partially gas injection. Statfjord Late Life entails that all injection now has ceased. To release the solution gas from the remaining oil, depressurisation of the reservoirs started in 2007.
STATUS
Work is ongoing to extend the lifetime of the field. Plans include prolonging the lifetime of the platforms and drilling of many new wells in the years to come. Satellite fields tied-back to Statfjord as well as nearby discoveries will benefit from the lifetime extension.
DEVELOPMENT
Statfjord is a field in the Tampen area in the northern part of the North Sea, on the border between the Norwegian and UK sectors. The Norwegian share of the field is 85.47 per cent. The water depth is 150 metres. Statfjord was discovered in 1974, and the plan for development and operation (PDO) was approved in 1976. The field has been developed with three fully integrated concrete facilities: Statfjord A, Statfjord B and Statfjord C. Statfjord A, centrally located on the field, came on stream in 1979. Statfjord B, in the southern part of the field, in 1982, and Statfjord C, in the northern part, in 1985. The satellite fields Statfjord Øst, Statfjord Nord and Sygna have a dedicated inlet separator on Statfjord C. A PDO for Statfjord Late Life was approved in 2005.
RESERVOIR
Statfjord produces oil and associated gas from Jurassic sandstone in the Brent and Statfjord Groups, and in the Cook Formation. The Brent and Statfjord Groups have excellent reservoir quality. The reservoirs lie at a depth of 2,500-3,000 metres in a large fault block tilted towards the west, and in several smaller blocks along the eastern flank.
TRANSPORT
Stabilised oil is stored in storage cells at each facility. Oil is loaded onto tankers from one of the two oil-loading systems on the field. Since 2007, gas is exported through Tampen Link, and routed via the Far North Liquids and Gas System (FLAGS) pipeline to the UK. The UK licensees route their share of the gas through the FLAGS pipeline from Statfjord B to St Fergus in the UK.