French oil and energy group Total said on Monday it made a major gas discovery on the Glendronach prospect, located off the west coast of the Shetland islands in the North Sea.

Wood Mackenzie North Sea research analyst Kevin Swann told Reuters the find was the largest conventional discovery in the UK since Culzean in 2008, and it could contribute as much as 10% of the UK’s annual gas production in its early years.

“Exploration in the UK has been a huge concern so far in 2018 with just five exploration wells spudded to date – on track for lowest levels of activity since the 1960s … so this discovery is welcome news,” said Swann.

Total said in a statement: “Preliminary tests confirm good reservoir quality, permeability and well production deliverability, with recoverable resources estimated at about one trillion cubic feet.”

The Glendronach discovery is operated by Total E&P UK with a 60% interest alongside partners Ineos E&P UK Limited (20%) and SSE E&P UK Limited (20%).

“Glendronach is a significant discovery for Total which gives us access to additional gas resources in one of our core areas and validates our exploration strategy,” said Arnaud Breuillac, president exploration & production at Total.

“Located on an emerging play of the prolific West of Shetland area, the discovery can be commercialized quickly and at low cost by leveraging the existing Laggan-Tormore infrastructure.”

Total added: “Located on Block 206/04a, in water depth of about 300 meters and in a formation below the Edradour reservoir, the discovery can be developed quickly with the existing infrastructure around the Edradour field and the Laggan-Tormore facilities of the Shetland Gas Plant.”

Oil & Gas UK’s chief executive, Deirdre Michie, said: “This is a major discovery by Total which demonstrates the exciting potential the West of Shetland frontier region holds.

“The focus on quick commercialisation of this find, made viable by the UKCS’ existing infrastructure, provides motivation for investors as well as industry.

“As our Economic Report recently highlighted, an increase in drilling activity is key to unlocking the remaining potential of the UKCS.

“This significant discovery demonstrates that the improved competitiveness of the basin is having positive results.

“This is thanks to the hard work undertaken by industry since the downturn.

“It also highlights what can be achieved when companies maximise the potential yield from their existing blocks.

“This increased activity is critical as we look to maximise economic recovery from the UK Continental Shelf and realise Vision 2035.”

Martin Pibworth, SSE’s Wholesale Director, said: “This discovery represents a major addition to SSE’s recoverable gas resources.

“Gas production assets are a natural complement to SSE’s interests in gas-fired power generation and gas supply to business customers.

“They are expected to add to SSE’s earnings from gas production in due course.  In the meantime, we will continue to support exploration and appraisal activities around our existing assets.”

Total’s production in the UK comes principally from operated fields located offshore in three major zones — the Alwyn/Dunbar area in the Northern North Sea, the Elgin/Franklin area in the Central North Sea and the Laggan-Tormore hub in the West of Shetland area, and from recently acquired Maersk Oil assets.

Total also operates the Culzean gas field (formerly Maersk Oil operated) with a 49.99% working interest, scheduled to start-up in 2019.