Ekofisk, the oldest oil field in the Norwegian North Sea, contained approximately 129 million cubic metres of remaining recoverable reserves as of December 2012 making it the biggest oil field in Norway. The field is located 300km southwest of Stavanger in block 2/4 on the Norwegian Continental Shelf.
Phillips Petroleum Company discovered the Ekofisk field in 1969 and started producing oil from the field directly to tankers through four subsea wells in 1971. The offshore oil field has since then gone through many phases of development and modernisation, currently comprising of nine platforms. A wellhead platform and a combined field centre and accommodation platform installed in 2013 as part of the Ekofisk South development project are the newest platforms at the field.
ConocoPhillips, the operator of Ekofisk, holds 35.11 % interest in the offshore project, while the remaining interest is held by Total (39.9%), Eni (12.39%), Statoil (7.60%) and Petoro (5%). The field was estimated to produce 102,000 barrels of oil per day in 2013. Ekofisk is expected to be in production until 2050.
The Snorre oil field in blocks 34/4 and 34/7 in the Tampen area of the Norwegian North Sea contained estimated recoverable reserves of more than 64 million cubic metres as of December 2012 making it Norway's second biggest oil field.
The oil field commenced production in August 1992 with the integrated production, drilling and quarters (PDQ) platform Snorre A. The second platform named Snorre B, a semisubmersible PDQ platform installed about 7km north to Snorre A, was brought on stream in 2001. Oil from Snorre A is sent via pipe to the nearby Statfjord A platform for final processing, whereas the oil from Snorre B is piped to the Statfjord B platform for storage and export.
Statoil, which holds 33.31% ownership in the project, is also the operator of Snorre. Other stakeholders include Petoro (30%), ExxonMobil (11.58%), Idemitsu (9.6%), RWE (8.28%), Total (6.17%), and Core Energy (1.03%). The Snorre platforms were estimated to produce 85,000 barrels of oil per day in 2013 and the oil field is likely to remain in production until 2040.
The Valhall oil field located in blocks 2/8 and 2/11 in the Norwegian North Sea is the third biggest oil field in Norway. Remaining recoverable oil reserves of the field as of December 2012 were estimated at 41.5 million cubic metres.
Valhall was discovered in 1975, brought into production in 1982, and is currently operated with six bridge-linked platforms including a new combined production and hotel platform that started operation in January 2013 and two unmanned flank platforms located in the southern and northern parts of the field. The new Valhall production facility has a design life of 40 years and oil production capacity of 120,000 barrels per day.
BP, holding 35.9% working interest, is the operator of Valhall, while Hess owns the remaining 64.1% interest in the field. Valhall was estimated to produce 45,000 barrels of oil per day in 2013 and is expected to be in production until 2050.
The Heidrun oil field located 190km off the west coast of Norway in the Haltenbanken region in the Norwegian Sea contained 40.1 million cubic metres of recoverable oil reserves as of December 2012 making it the country's fourth biggest oil field.
Heidrun was discovered by Conoco in 1985 and was brought on stream with a floating tension leg platform with a concrete hull in October 1995. The oil field currently has 51 producing wells, 24 water injectors, and one gas injector. The oil output is transported via shuttle tankers to Statoil's Mongstad terminal near Bergen and also to Tetney in the UK.
Heidrun is scheduled to have a permanent floating storage unit (FSU) from 2015 onwards for which Samsung Heavy Industries was awarded a $230m contract in 2012.
Statoil operates the Heidrun field while holding a 12.41% interest, while the other stakeholders include Petoro (58.16%), ConocoPhillips (24.31%), and Eni (5.11%). Heidrun was estimated to produce 65,000 barrels of oil per day in 2013. The development partners plan to maintain Heidrun in production until 2045.
The Eldfisk field lying about 16km south to Ekofisk in block 2/7 of the Norwegian North Sea is Norway's fifth biggest oil field, possessing about 37.3 million cubic metres of recoverable oil reserves at the end of 2012.
The field commenced production in 1979 after nine years of its discovery, and is currently operated with four platforms, three of which are bridge connected. Eldfisk 2/7 Bravo, a new combined drilling, production and process platform of the field, is located about 6km northwest of the Eldfisk Complex. The oil produced from Eldfisk is sent to the nearby Ekofisk facility for storage and export.
ConocoPhillips operates the Eldfisk field with 35.11% ownership. Other stake holders include Total (39.9%), Eni (12.39%), Statoil (7.6%), and Petoro (5%). The field produced around 34,000 barrels of oil per day in 2013. A major development project namely the Eldfisk II project that includes installation of a new integrated platform and modernisation of the existing infrastructure is underway to extend the field's production up to 2050.
The Grane field located 185km from Haugesund in block 25/11 of the Norwegian North Sea was estimated to contain 36.1 million cubic metres of recoverable oil reserves as of December 2013 making it the sixth biggest oil field in Norway.
The field was discovered by Hydro in 1991 and came on stream in September 2003 with nine production and three injection wells. Grane was the first Norwegian field to produce heavy crude oil. The Grane platform currently features 40 well slots and pipes to the Sture terminal for storage and export.
Grane is operated by Statoil, which holds 36.66% ownership of the field. The other licence holders of the field are ExxonMobil (28.22%), Petero (28.94%), and ConocoPhillips (6.17%). The oil field was estimated to produce 98,000 barrels of oil per day in 2013. Grane's life is expected to be 25 years, thanks to a number of new wells planned at the field.
Oseberg, estimated to hold 22.7 million cubic metres of recoverable oil reserves at the end of 2012, is Norway's seventh biggest oil field. The Oseberg oil field is located in water depths of 100m in the northern part of North Sea.
The field, discovered in 1979 and brought on stream in 1988, was developed in multiple phases. It comprises four platforms namely Oseberg A, B, C and D. The A, B and C are three bridge linked platforms located in the southern part of the field, while the Oseberg D is gas processing platform located 14km north of the field centre. Oil from the Oseberg field is transported through the Oseberg Transport System (OTS) to the Sture terminal near Bergen in western Norway.
Statoil, holding 49.30% interest, is the operator of Oseberg, while other licensees include Petero (33.60%), Total (10%), ExxonMobil (4.70%), and ConocoPhillips (2.4%). Oseberg was estimated to produce 59,000 barrels of oil per day in 2013.
At 18.6 million cubic metres of recoverable oil as of December 2012, Åsgard is Norway's eighth biggest oil field. The Åsgard field is located 50km south of Heidrun on the Halten Bank in the Norwegian Sea.
The field was discovered in 1981 and started oil production in 1999. It was developed in two phases that involved the drilling of 52 wells through 16 seabed templates. Oil is produced and stored in the vessel Åsgard A, while two other facilities namely Åsgard B and C are used for processing and storage of gas and condensates from the field. The oil produced from the Åsgard field is shipped by shuttle tankers.
Statoil with 34.57 % ownership is the operator of Åsgard field, while the other stakeholders of the field are Petero (35.69%), Eni (14.82%), and ExxonMobil (7.24%). The estimated daily oil output of Åsgard in 2013 stood at 55,000 barrels.
The Alvheim oil field, located west of Heimdal in the Norwegian North Sea, contained 17.5 million cubic metres of oil in recoverable reserves as of December 2012 making it the ninth biggest oil field in Norway.
The oil field is divided into three areas Kamelon, Boa and Kneler and was brought on stream in 2008 after 10 years of discovery. The field is currently operated with 15 subsea producing wells tied back to the Alvheim FPSO. Oil from the FSPO is buoy-loaded to tankers.
Marathon, holding 65% interest, is the operator of the Alvheim field, while ConocoPhillips (20%) and Lundin (15%) hold the remaining interest in the asset. Alvheim was estimated to produce 59,000 barrels of oil per day in 2013, and is expected to remain in production until 2032.
The Oseberg Sør field located south of the Oseberg field in the northern part of the North Sea is the tenth biggest oil field in the Norwegian Shelf by reserve. The oil field was estimated to contain 17.2 million cubic metres of recoverable oil reserves as of December 2012.
Oseberg Sør was discovered in 1984 and brought on stream in 2000. It is developed with an integrated drilling, accommodation, and first stage oil and gas separation facility. A number of deposits at the field are tied back to the Oseberg Sør platform by means of subsea templates. Oil from the Oseberg Sør facility is sent to the Oseberg Field Centre for final processing.
Statoil, with 49.3% interest, is the operator of the Oseberg Sør field, while Petero (33.6%), Total (10%), ExxonMobil (4.7%) and ConocoPhillips (2.4%) hold the remaining interest in the field. Daily oil production from Oseberg Sør during 2013 was estimated at 46,000 barrels.