One of them manages to leave a sound-emitting device that temporarily interrupts proceedings at the Energy Ireland conference.

Tony O'Reilly Jnr, chief executive of Providence Resources, shakes his head at the disturbance. He is frustrated by the commonly conceived notion that Ireland's offshore natural resources have been 'given away' and points to the massive expenditure that companies such as his must stump up with zero guarantee of a lucky strike.

Providence Resources has been around in one guise or another since the 1980s, when it was known as Atlantic Resources. Since then, says the current chief executive, the O'Reilly family has sunk "millions of euro" into exploration. One would imagine that it's time for some payback. Tony O'Reilly hopes that day is closer than it's ever been.

"If ever there was a time to be doing this, it's now, " he says, pointing to the high oil and gas prices that have industry giants such as Chevron posting record profits (in the last quarter the world's five biggest oil companies reported a combined profit of almost $32bn).

The major play for Providence Resources is the massive Dunquin prospect in the Porcupine Basin off the southwest coast. Earlier this year, ExxonMobil, the world's biggest oil company, agreed to buy in to the project (it now owns an 80% stake) and next year will drill two wells at deep ocean targets. Each drilling project is likely to cost $50m and there's no guarantee that anything will be found. But the potential payoff is nothing short of staggering. Seismic data has shown there could be as much as 20 trillion cubic feet of gas (Corrib contains roughly one trillion) and three billion barrels of oil hidden far beneath the seabed. If reserves could be tapped into, the result could transform the Irish economy and provide security of supply for years to come.

"People always say that Ireland is at the end of the European gas pipeline network, " says O'Reilly. "Someday I want the country to be the start of it."

Other prospects, including Spanish Point (also in the Porcupine Basin) and others in the Celtic Sea (a survey agreement for prospects there was inked in September and has just been completed) and off Nigeria, could also provide generous returns for Providence's investors. To the outsider, though, it all sounds like an 'ifs and buts' game. And it is.

"You need a bit of luck, but it's like the guy who prays to win the lottery every night.

Eventually God tells him: 'Ok, I'll help, but at least buy a ticket first.'" Vast amounts of money need to be spent to ever have a hope of any return. That's the primary reason why the government seeks no royalty payments from oil or gas finds. There has to be some incentive to the industry to shoulder the massive outlays for surveys, drilling and rig hiring. More than ever, the security-of-supply issue is top of the agenda.

Last week the International Energy Agency (IEA) warned that Russia may not invest enough in infrastructure to maintain natural gas exports to Europe in coming years. The IEA also pointed out that for majors such as Royal Dutch Shell and BP, increased capital spending "is to a large extent illusory" because it is "blunted" by rising costs for labour and equipment such as drilling rigs and steel piping.

"With the energy demand in Europe, and the concerns about supply shocks, there is a real desire to find secure and reliable oil and gas resources, " according to O'Reilly. "I keep saying that Ireland offers a unique opportunity to the oil and gas industry, in the same way as it did to pharmaceutical or technology companies that came here.

"I think what the international market wants, though, is for it to demonstrate itself as a producer of hydrocarbons, " O'Reilly adds. "When that happens it will create more exploration and development investment."

To date the track record has been poor. In the past 30 years or so, prospectors have forked out over 2bn to sink more than 140 test wells in the seas around Ireland, but there is little to show for all the investment. Yet. Prior to Corrib, the last big find was Kinsale, over 20 years ago.

It's now almost dry.

O'Reilly points out that 81% of the gas we use is imported, along with 100% of the oil.

It's clear, then, that a big find could have dramatic positive consequences for the country.

If you want to be in the exploration business, enthusiasm has to be in your bones.

The long lead times, frequent disappointments and constant search for the 'big find' can surely become wearing.

Even if ExxonMobil was to find commercially extractable oil or gas tomorrow, it could take up to 10 years to bring a development on stream. A find in the shallower Celtic Sea could be brought to fruition a lot quicker.

He says the next two years will be "pivotal" for Providence Resources. During that time there will undoubtedly be a tense wait on the results ExxonMobil generates from its drilling programme in Dunquin.

At the moment Providence stock trades at just over seven cents. During the summer the company's broker, Davy, said that successes in the two Dunquin projects could add a potential 79 cents per share to the company's value, transforming it into a 1.5bn entity.

More importantly, they would at last provide definitive proof that offshore Ireland can offer big returns.