Afloat.ie previously reported on the Irish mineral exploration group's discovery in April this year, when the company confirmed the presence of light oil with an appraisal well at the site in the north Celic Sea.
Then on 15 March the firm announced that oil had begun to flow successfully from the Barryroe structure at a rate that could be worth billions of euro to the Irish economy.
The latest news suggests it could be worth even more over a longer period of time, as data compiled from six test wells on the site along with seismic data have led experts to estimate the field contains between 1 and 1.6 billion barrels of oil.
“It is clear that Barryroe is a substantial oil accumulation across multiple stacked horizons with much running room for further resource growth," said Providence chief executive Tony O'Reilly Jr.
The company also expects to begin explorations off Dalkey Island in Co Dublin by the end of the year, pending approval of its foreshore permit.
The so-called 'Dalkey Island prospect' has sparked much debate about its potential risks and benefits among the local community.