The COSLPromoter drilling rig. (Photo: COSL)

Equinor has awarded COSL Offshore Management AS a contract to drill four wells on Statfjord Øst with the COSLPromoter rig from the spring of 2023. In addition, the rig has options for drilling five wells for Statfjord satellites afterwards.

The contract value is calculated at around USD 56 million for the fixed part of the contract, which has an estimated duration of 220 days.

The value includes drilling and completion services, fuel, treatment of wastewater, handling of cuttings and upgrading of the rig by installing an automatic drilling control system. Additional services include running of casing, remote-operated vehicle (ROV), mobilisation and demobilisation, calculated at around USD 4 million.

After the preliminarily planned work programme has been completed, the intention is to extend the cooperation by continuing options. Prior to the planned work programme, options for any other tasks have been agreed. After drilling for Equinor on the Troll field from April 2013 to April 2021, the COSLPromoter rig is currently in hot lay-up at the CCB base outside Bergen.

“With this contract Equinor shows continued demand for smaller rigs on the Norwegian Continental Shelf as long as they are competitive and fit for the required drilling operations. The rig will be anchored at Statfjord Øst, helping maintain a low carbon emission level. We are pleased that COSL assumes responsibility for the fuel consumption, and they are working on several technologies and measures to reduce their emissions. This work will be important to us going forward,” says Mette Ottøy, chief procurement officer (CPO).

The rig will have a key role in Equinor’s commitment to extending the life of late-life fields (FLX), where safety, efficiency, new ways of working and low emissions are central to maintaining profitable operation.

“We are pleased to continue the good cooperation with this rig, which has provided safe and efficient deliveries to us for eight years on the Troll field. We are also looking forward to continuing our effort on late-life fields together with an experienced player, and we have high expectations to COSL helping us reach our FLX ambitions,” says Erik G. Kirkemo, senior vice president of drilling & well operations.

“We will focus on simple and standardised well solutions and successful improvements, in addition to proving that mature fields can also offer profitable production for many more years and hence contribute to production to 2040 from the Statfjord area,” he says.

The rig contract was signed digitally by Mette H. Ottøy (left), chief procurement officer, and Frank Tollefsen, CEO of COSL Offshore Management AS. (Photo: Kjetil Eide / Equinor ASA)

Partners of the Statfjord Øst licence are: Equinor Energy AS (31.6875% - operator), Petoro AS (30%), Vår Energi AS (20.55%), Spirit Energy Norway AS (11.5625%), Idemitsu Petroleum Norge AS (4.8%), Wintershall Dea Norge AS (1.4%).

The Statfjord area

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.

Statfjord B

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.

The field will remain in production until 2025 and possibilities to furter expand the lifetime are being looked into.

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 Norwegian share of gas from the field is piped to the Kårstø processing complex north of Stavanger and on to continental Europe.

Britain’s 14.53 per cent of the gas travels by pipeline via the Brent field to Scotland.

Cargoes are allocated between the field licensees in proportion to their interest in the respective licences.

STORAGE CAPACITY

• The storage cells on the Statfjord A hold 206 000 standard cubic metres, 1,3 million barrels of oil
• The storage cells on the Statfjord B hold 302 000 standard cubic metres, 1,9 million barrels of oil
• The storage cells on the Statfjord C hold 302 000 standard cubic metres, 1,9 million barrels of oil

OIL AND GAS PRODUCTION

The hydrocarbon reservoir formations on Statfjord lie at depths of 2 500-3 000 metres. They consist of sandstones, with the oil and gas held in pores between the individual sand grains. These hydrocarbon-bearing sediments were all deposited in the Jurassic era, about 150 million years ago.

The production record for a single day on Statfjord was set on 16 January 1987, when 850 204 barrels were produced.

Roughly four million cubic metres of gas are exported daily by the Statfjord Unit.

Topside weight: 42,500 tons
Concrete substructure weight: 310,500 tons
Storage volume: 302,000 m3
Total height: 271 metres
Living quarters accommodate: 228 people.
Production start: 5 November 1982.

Statfjord C

Topside weight: 50,000 tons
Concrete substructure weight: 290,000 tons
Storage volume: 302,000 m3
Total height: 290 metres
Living quarters accommodate: 345 people.
Production start: 26 June 1985. The field is likely to remain in production until 2025. 
Area: 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
Production: Oil and gas

Statfjord Nord

Statfjord Nord was discovered by Norskald in 1977 and lies in block 33/9.

This field and Statfjord Øst are tied back to the Statfjord C platform as satellite developments.

Statfjord Nord lies about 22 kilometres north-east of Statfjord C, and has been developed with three subsea templates (D, E and F). These installations are tied back to Statfjord C with 10-inch flowlines. The D template is for water injection, while the other two handle oil production.

All installations on the field are subsea, and remotely operated from Statfjord C.

Location: Block 33/9
Production: Oil and gas

Statfjord Øst

Statfjord Øst was discovered by Norskald in 1977, and began production on 23 September 1994.

This field and Statfjord Nord are tied back to the Statfjord C platform as satellite developments.

Statfjord Øst lies five kilometres north-east of Statfjord C, in production licences 037 and 089.

Like the nearby Statfjord Nord field, this discovery has been developed with subsea installations tied back to Statfjord C by flowlines.

Statfjord Øst is provided with three subsea templates (K, L and M). The K structure is for water injection, while the other two handle oil production.

Location: Five kilometres north-east of Statfjord C
Production start: 24 September 1994
Production: Oil and gas

Sygna

The Sygna oil field is located in the north-east corner of the Statfjord area in the Norwegian North Sea.

It began producing on 1 August 2000, and will most likely remain in production until the end of 2019.

Sygna is shared between two production licences: 55 per cent lies in block 33/9 (Statfjord), and the remainder falls inside block 34/7 (Snorre). The development solution embraces a subsea template tied by a pipeline to the Statfjord C platform, which is 22 kilometres away.

Two production wells have been drilled through the template, and water will also be injected into the reservoir through an extended-reach well drilled from the Statfjord Nord satellite.

Location: In the north-east corner of the Statfjord area in the Norwegian Sea
Production start: 1 August 2000
Production: Oil

KeyFacts Energy: Equinor Norway country profile