Oil giant ExxonMobil kicks off a $160m-plus (€125m) drilling programme off the west coast of Ireland this weekend with hopes that confirmation of major fossil fuel reserves will transform the country's economy.
The US company is planning to drill test wells over a four-month period at two prospects at the Dunquin licence area in the Porcupine Basin, 200km off shore.
Previous data has suggested that there could be over 300 million barrels of oil and 8.5 trillion cubic feet of gas between the two Dunquin prospects.
If they could be proven and then extracted, such finds would mark one of the biggest ever global discoveries of oil and gas and be a game-changer for Ireland's economic fortunes.
But despite the 200 or so wells drilled off Ireland's shores in the past number of decades, only two have resulted in commercial fields – Kinsale and Corrib.
Both are minnows compared to the prospective resources that could be hidden at Dunquin. Kinsale had about 1.5 trillion cubic feet of gas, while Corrib has about one trillion.
Located at a point in the Atlantic where the ocean is 1.6km deep, ExxonMobil's drilling programme is being eagerly watched by oil companies from abroad and Ireland, including Petrel Resources, which has an exploration block just 35km away from the Dunquin prospect.
ExxonMobil controls 27.5pc of the Dunquin prospect, with Italian firm Eni holding another 27.5pc.
Spanish energy firm Repsol owns 25pc and UK-based Sosina has a 4pc interest. Irish exploration firm Providence Resources has a 16pc interest in the prospect. A major oil or gas find could catapult its shares higher.
The Dunquin prospect – where the reserves are as deep as 3.6km under the seabed – is one of the most important exploration areas for Providence, which is headed by Tony O'Reilly Jnr.
Providence is also betting that it could have a major oil find on its hands at a site called Barryroe, which is close to the Kinsale field. The company reckons that there could be 280 million barrels of recoverable oil at the Barryroe prospect.
ExxonMobil has spent $20m to bring the exploration rig from west Africa to Ireland's waters. The rig is owned by Norwegian group Ocean Rig. ExxonMobil will spend over $1m a day on the drilling activities, which are expected to last between 90 and 120 days.
The Department of Transport has already issued a warning to shipping in the area. It says that the semi-submersible rig, called the Eirik Raude, will be supported by supply vessels operating out of the port of Cork.
A 500-metre exclusion zone will be enforced around the rig for the duration of the drilling.
"All vessels, particularly those engaged in fishing, are requested to give the Eirik Raude a wide berth and keep a sharp lookout in the relevant area," said the department.
The port of Cork is also hoping that it could become an epicentre for Ireland's oil-and-gas industry if offshore reserves are proven.