An Irish company says it has found the Republic's first viable oil well.
Oil exploration company Providence Resources says it has made the discovery 70km off the Cork coast.
The firm said its exploratory Barryroe oil well delivered double the amount of oil needed for future full-scale extraction to make commercial sense.
The exploratory well yielded almost 4,000 barrels of oil a day. Providence Resources Plc also has drilling permits in Northern Ireland.
The company will now seek international investors to help it exploit the well and the surrounding field, which the firm hopes will contain many further viable wells.
The company's technical director, John O'Sullivan, said: "Oil was discovered by Esso in the 1970s, but it was never commercial, as oil prices were a lot lower.
"The oil price has gone from $10 to $15 a barrel to $125 a barrel.
"Our target was 1,800 barrels from this well. So we drilled and we got 3,500 barrels, which is twice our target for a commercial threshold. This has far exceeded what we expected."
Providence chief executive Tony O'Reilly Jr paid tribute to the team for delivering such a successful outcome within what he described as "a challenging 15-month timeline".
"We are a company who have been doing this for 30 years. We are not in any way fly-by-nights coming in to make money and get out.
"We will bring in partners to co-venture with us, but ultimately we are doing a drilling programme."
Talking about the possibility of drilling off the north coast, near Rathlin island, Mr O'Reilly said: "We are very encouraged about that. We would be looking to do our exploration programme there. Obviously, we have to go through a consultative process and we have started to do that. It is a major interest area for us."
Providence assumed operatorship of the Barryroe oil well in late 2010.
BBC business correspondent Joe Lynam said: "This is Ireland's very first commercially viable well. They have found lots of little things in the past, but not something that can be translated into hard dollars."
Mr Lynam said that following the announcement on Thursday, the company's shares rose by 18%.