Gas production has got under way from an “impossible” North Sea field discovered more than 40 years ago when the technology did not exist to allow extraction.
US oil company Chevron said the Alder project, around 100 miles off the Scottish coast, had already created hundreds of jobs throughout the UK, including in Aberdeen and Invergordon.
The scheme has been estimated at around £1.5 billion and is expected to produce up to 110 million cubic feet of gas and 14,000 barrels of gas condensate per day at its peak.
The company said development was originally considered impossible due to the challenges of the field’s reservoir, lying 14,700ft (4,480m) beneath the seabed.
The company said it was now viable due to the “right combination of technology, infrastructure for processing and export, and commercial conditions”.
Greta Lydecker, Chevron Upstream Europe managing director, said: “First gas at Alder represents a significant milestone for Chevron and highlights our commitment to investing and developing resources in the UK.
“The safe and successful completion was underpinned by strong collaboration between Chevron and Alder co-venturer ConocoPhillips.
“Alder supports our goal of helping maximize the economic recovery of the UK, adds significant production to our portfolio, and helps extend the field life of Britannia, an important asset to Chevron in the North Sea.”
The Alder field, discovered in 1975, is now viable due to innovative subsea technologies designed to meet its temperature and pressure challenges.
Key technologies include a vertical mono-bore subsea tree system; a subsea high integrity pressure protection system and a specially designed corrosion monitoring system to measure the real-time condition of the production pipeline.
Andy Samuel, chief executive at the Oil and Gas Authority, said: “We are very pleased to see the safe flow of first gas from the Alder Field. Chevron’s application of innovative subsea technologies and use of the UK’s experienced supply chain is closely aligned to the Maximising Economic Recovery Strategy, adding reserves and extending the life of an existing asset.”