Elgin-Franklin

Location and Geology

• The Elgin and Franklin fields are located in the UK North Sea, approximately 240 km east of Aberdeen in the Central Graben Area.
• Elgin field is situated in blocks 22/30b, 22/30c, and 29/5b, while Franklin field is located in block 29/5b, about 6 kilometers southeast of Elgin.
• The water depth at both fields is around 92-93 meters.

Discovery and Ownership

• The Elgin field was discovered by Elf in 1991, and the Franklin field was discovered by Ultramar Corp. in 1986.
• The operator of the fields is TotalEnergies (previously TotalFinaElf), with a 46.17% stake. Other partners include Chrysaor (now part of Harbour Energy), Eni, ExxonMobil, Ithaca, One Dyas, Premier Oil, and others.

Development and Infrastructure

• The Elgin-Franklin project is the world's largest high-pressure/high-temperature (HP/HT) development, with reservoir pressures of approximately 1,100 bar and temperatures of around 190°C.
• The development includes a large processing, utilities, and quarters (PUQ) platform located in the Elgin field, connected to two wellhead platforms – one in Elgin and one in Franklin. The Elgin wellhead platform is linked to the PUQ by a 100-meter access bridge, while the Franklin platform is connected via an inter-field pipeline system.
• The PUQ platform has the capacity to process 525 million cubic feet per day (MMcfd) of gas and 175,000 barrels per day (b/d) of condensate.

Production

• Production from the Elgin field began in March 2001, and from the Franklin field in August 2001. Initial production rates were 13,500 b/d of condensate and 1.2 MMcm of gas from Elgin, with combined peak production expected to reach 140,000 b/d of condensate and 13 MMcm of gas.
• The fields achieved peak production of 140,000 barrels of condensate and 485 million cubic feet of gas per day by March 2002, contributing approximately 7% of total UK production.

Economic and Operational Aspects

• The total investment in the Elgin-Franklin project was approximately £1.65 billion ($2.6 billion), with the project completed within budget and within 48 months from sanction to start-up.
• The development required the drilling of 10 new wells, five in each field, along with the tie-back of an appraisal well and the discovery well in Elgin. The drilling program was complex due to the HP/HT nature of the reservoirs, necessitating early drilling to avoid depletion issues.
• The project employed over 5,000 people during peak construction and created 160,000 man-months of work in the UK. About 82% of the contracts were awarded to UK industry.

Export Facilities

• Hydrocarbons from both fields are processed on the PUQ platform and then exported ashore via separate lines. Gas is exported through the SEAL (Shearwater Elgin Area Line) pipeline, which connects to the Transco terminal at Bacton and the Interconnector pipeline for transmission to the Continent. Condensate is shipped through the Graben Area Export Line (GAEL) and the Forties Pipeline System (FPS) to Kinneil for stabilization.

Life Extension and Current Status

• Despite initial expectations of producing fewer than 800 million barrels of oil equivalent (boe), the Elgin-Franklin fields have exceeded expectations, producing over 1 billion boe as of 2020.
• Total is considering a life extension for the fields, involving facilities and integrity work to maintain production beyond the original forecasted end date of 2022. The infrastructure is now expected to be operational until at least 2040.

Challenges and Innovations

• The project required significant preparatory research and development, with £21 million ($34 million) spent between 1993-96 to master the necessary technologies. The HP/HT nature of the reservoirs posed considerable development challenges, necessitating innovative solutions such as the use of a jack-up-style PUQ platform that could be built onshore and then refloated and removed once the fields are depleted.

In summary, the Elgin-Franklin project is a landmark HP/HT development in the North Sea, characterized by its complex geology, innovative infrastructure, and significant economic and operational achievements.