IT started 26 years ago in a small office down in Tullow Co Carlow. Today its interests span four continents, has a worth measured in billions and is on the cusp of joining the major league of oil producers worldwide.

So where along the way did founding chief executive Aidan Heavey realise he had made material his dream of running a major oil company? "I have been asked that several times and the truth is you don't notice. It creeps up on you."

He does, however, admit to a moment of realisation when last year he signed a contract to hire one of the largest rigs in the world for a five-year term -- that at a cost of $1m a day or a possible outlay of $1.85bn.

It is a novel idea, but using seismic surveys Tullow's geophysicists have identified major prospects offshore Guyana, Suriname and French Guiana which mirror those on the African side.