A significant gas discovery in the central North Sea is being described as the biggest find in more than a decade.
Chinese state-owned company CNOOC said it made the gas discovery - equivalent to 250 million barrels of oil - in its Glengorm project, east of Aberdeen.
Further appraisal work is planned, but it is understood it could be extracted using existing infrastructure.
Friends of the Earth Scotland said the find was terrible news for the climate.
Glengorm sits 118 miles (190km) east of Aberdeen, close to Total's Elgin-Franklin and Culzean fields, and could be tied back to one of their platforms.
Total owns a 25% stake in the Glengorm field.
Xie Yuhong, of CNOOC, said the company was "looking forward to further appraisal".
Still life in mature waters
Kevin McLachlan, of Total, added: "Glengorm is another great success for Total in the North Sea, with results at the top end of expectations and a high condensate yield in addition to the gas.
"Our strong position in the region will enable us to leverage existing infrastructures nearby and optimise the development of this discovery.
"Glengorm is an achievement that demonstrates our capacity to create value in a mature environment thanks to our in-depth understanding of the basin."
Analysts Wood Mackenzie described the find as the largest in the North Sea since the Culzean field was discovered in 2008.
Senior analyst Kevin Swann said: "There is a lot of hype around frontier areas like West of Shetland, where Total discovered the Glendronach field last year. But Glengorm is in the Central North Sea and this find shows there is still life in some of the more mature UK waters."
Environmental groups have criticised the discovery which, they say, will further contribute to climate change.
They want energy companies to leave oil and gas in the ground and focus instead on renewable sources.
Caroline Rance, from Friends of the Earth Scotland, said: "It's a disgrace that oil and gas exploration is still going ahead in the seas off Scotland.
"It's high time our governments stopped supporting fossil fuel development, and get serious about planning a just transition away from this industry.
"These companies know all too well that their business is built on the destruction of the climate, which is devastating for millions of people around the world but they continue to seek profit from driving this catastrophe."
The Oil and Gas Authority has welcomed the discover, and said it demonstrated the considerable potential the industry still had to offer.
Chief executive Andy Samuel said: "This is very exciting news. Glengorm was first mapped as a prospect around 20 years ago and it is great to see CNOOC taking up the exploration opportunity and completing a difficult high-pressure, high-temperature exploration well.
"Our official estimate is that there still remains between 10 and 20 billion barrels plus to be recovered, so there is every chance of yet more significant finds, provided industry can increase exploration drilling and capitalise on the real value to be had here in the UK."
Energy Minister Paul Wheelhouse said the announcement, "highlights the significant potential for oil and gas which still exists beneath Scotland's waters".
He added: "Scotland's offshore oil and gas industry has an important role to play with up to 20 billion barrels of oil equivalent remaining under the North Sea and in the wider basin and discoveries such as this help to support security of supply as we make the transition to a low carbon energy system."