1. Troll Oil and Gas Field, Norway – 5.18 billion barrels of oil-equivalent
The Troll oil and gas field is located in the northern part of the North Sea, Norway. It includes two structures, Troll Øst and Troll Vest, which lie in blocks 31/2, 31/3, 31/5 and 31/6.
The field is jointly owned by Equinor Energy (30.58%, operator), Petoro (56%), Norske Shell (8.10%), Total E&P Norge (3.69%), and ConocoPhillips Skandinavia (1.62%). It commenced production in September 1995 and is estimated to contain approximately 40% of the gas reserves held within the Norwegian continental shelf (NCS).
Equinor Energy is currently undertaking the third phase development of the field, which will extend its life beyond 2020 and produce 2.2 billion barrels of oil-equivalent (Bboe).
2. Johan Sverdrup Oil Field, Norway – 2.7 billion barrels of oil-equivalent
The Johan Sverdrup oil field is one of the five biggest fields located in the NCS. It lies on the Utsira Heigh of the North Sea, Norway.
The field is jointly owned by Equinor Energy (40.02%, operator), Lundin Norway (22.6%), Petoro (17.36%), AkerBP (11.57%), and Total (8.44%). It is estimated to hold remaining recoverable reserves of 2.7Bboe.
Johan Sverdrup is being developed in two phases with the first phase scheduled to commence production in November 2019. The second phase is currently under construction and expected to begin production in the fourth quarter of 2022.
3. Snøhvit Gas Field, Norway – 1.14 billion barrels of oil-equivalent
The Snøhvit gas field is located in the Hammerfest Basin of the Barents Sea, Norway. It includes three fields, namely Snøhvit, Albatross and Askeladd. The Snøhvit and Albatross fields commenced production in 2007, while Askeladd is scheduled to produce first oil in 2021.
The field is jointly owned by Equinor Energy (36.8%, operator), Petoro (30%), Total E&P Norge (18.4%), Neptune Energy (12%), and DEA Norge (2.8%).
Snøhvit is the first field in the NCS to be developed without the installation of fixed or floating units. It is developed using subsea production facilities installed on the seabed.
4. Buzzard Field, UK – 700 million barrels of oil-equivalent
The Buzzard field is located 96km north-east of Aberdeen, UK, in blocks 19 and 20 of production licences P986 and P928. It is considered as the country’s highest-producing field.
The field is jointly owned by CNOOC Petroleum Europe (43.21%, operator), Suncor Energy UK (29.89%), Chrysaor (21.73%), Dyas Exploration UK (4.70%), and Oranje-Nassau Energie Resources (0.46%).
CNOOC launched the second project phase in 2007, which includes the installation of a 12-slot production and injection manifold connected to the Buzzard complex. First oil from phase two is expected in 2021.
5. Ormen Lange Gas Field, Norway – 653 million barrels of oil-equivalent
Ormen Lange gas field is located in the southern part of the North Sea, 120km offshore Norway. It supplies approximately 20% of the UK’s gas needs, through the 1,200km-long Langeled pipeline.
The field is owned by Petoro (36.48%), Equinor Energy (25.34%), Norske Shell (17.81%, operator), INEOS E&P Norge (14.02%), and ExxonMobil Exploration and Production Norway (6.33%).
Production from the Ormen Lange field has been declining as the reservoir pressure reduces. Two subsea compression options are being explored to boost the production. The best option is expected to be chosen in 2019.
6. Clair Ridge Oil Field, UK – 640 million barrels of oil-equivalent
The Clair Ridge oil field lies in block 206/08 west of the Shetland Islands, UK. It is the biggest field located on the UK continental shelf.
BP is the field operator with a 45.1% interest while the remaining interest is held by ConocoPhillips (45.1%), Shell UK (28%), and Chevron North Sea (19.4%).
The field is being developed in two phases, of which the first phase commenced production in 2004. The second phase is being developed north of the first phase and includes the installation of two fixed steel jacket platforms. Construction is underway and commissioning is expected in 2019.
7. Snorre Oil and Gas Field, Norway – 577 million barrels of oil-equivalent
The Snorre oil and gas field lies in blocks 34/4 and 34/7 of the Tampen area of the North Sea, offshore Norway. It has been in production since 1992 through two platforms, namely Snorre A and Snorre B.
The field is jointly owned by Equinor Energy (33.27%, operator), Petoro (30%), ExxonMobil Exploration and Production Norway (17.44%), Idemitsu Petroleum Norge (9.6%), DEA Norge (8.57%), and Vår Energi (1.11%).
An expansion plan for the project was approved in July 2018 to increase recovery from the field. It is expected to expand the field’s life beyond 2040 and the recovery rate by up to 51%. It is expected to commence production in 2021.
8. Oseberg Oil and Gas Field, Norway – 567.97 million barrels of oil-equivalent
The Oseberg oil and gas field located in the North Sea, Norway, was developed in several phases, with first production achieved in 1988.
Equinor Energy, the operator, holds 49.3% interest in the field. The remaining interest is held by Petoro (33.6%), Total E&P Norge (14.7%) and ConocoPhillips Skandinavia (2.4%).
The field is produces oil and gas using four platforms named Oseberg A, Oseberg B, Oseberg C, and Oseberg D. Development of the western flank of the field was approved in 2016 and included the installation of an unmanned wellhead platform.
9. Johan Castberg Oil Field, Norway – 559.16 million barrels of oil-equivalent
Johan Castberg oil field is located in the production license 532 of the Barents Sea, Norway. It includes the development of three oil discoveries named Skrugard, Havis, and Drivis.
The field is owned by Equinor Energy (50%, operator), Eni (30%), and Petoro (20%). It is estimated to produce for approximately 30 years, at the current production rate.
The development plan for the project was approved in June 2018. It includes the installation of a 200m-long production, storage, and offloading vessel (FPSO) and drilling of 18 production wells. Oil will be recovered through gas and water injection. First production is expected to be achieved in 2020.
The Ekofisk oil and gas field is located in the southern part of the North Sea, offshore Norway. Located in block 2/4 of the production licence 018, the field produced first oil in 1971.
ConocoPhillips Skandinavia is the field operator with an interest of 35.1%, while the remaining interest is held by Total E&P Norge (39.89%), Vår Energi (12.38%), Equinor Energy (7.6%), and Petoro (5%).
The field is installed with nine platforms and bridge supports, which also handle production from nearby fields.