IRISH oil and gas company Providence Resources said new interpretations of old data suggest that a field off the west coat of Ireland contains as much as 200 million barrels of oil and gas, which would make it as big as the Corrib find and twice as valuable.
Drilling about 170km off the coast and 400 metres deep will begin in 2012 at the explorer's Spanish Point project and oil and gas could begin flowing by late 2014 or 2015, Providence said yesterday.
The company has identified the primary appraisal well location, where it will begin drilling.
Shares in Providence have jumped around 50pc since the beginning of the month on hopes that several projects where Providence has a large stake will soon bear fruit.
The company is also positive about the prospects for oil at a field off Dublin and is set to drill in six different basins over the next two years.
"If we find oil in any one, it's a game changer," said chief executive Tony O'Reilly.
A 200-million-barrel find of 75pc gas and 25pc oil would meet Ireland's gas needs for several years and around a fifth of the country's oil needs.
It would only be the fourth time in 40 years that an oil field was commercially developed in Irish waters.
"This is not only a significant event for Providence and its partners, but for the whole Irish offshore (industry)," Mr O'Reilly said. "There will be lots more (good news). We have many things in the hopper," he added.
Providence is using a new computer programme that produces a three-dimensional image of the sea bed based on existing information.
Such programmes are common in the oil industry these days and have reduced the element of surprise when oil companies begin drilling.
"It is like moving from a chalk board to an iPad," Mr O'Reilly said yesterday.
Providence has a majority interest while UK-based Chrysaor E&P Ireland has a 30pc stake and UK-based Sosina Exploration a 14pc interest. The partners may have to invest around $1bn (€743m) to extract the oil and gas, he said.
"That will be good for Ireland, good for the people of Ireland. They are no losers," he added.