There's more gas off the coast of Co Mayo than originally estimated, according to an offshore sub-sea survey in the Corrib gas field.
Commercial gas is set to flow from the field in the middle of next year after a series of delays.
The partners in the project — Shell, Statoil and Vermilion — are expected to spend an additional €300m on the project this year to bring the total spend to €3.4 bn by year's end.
Now, new accounts filed Canadian-based firm, Vermilion Energy Ireland Ltd — show that the volume of gas at peak production will be 8% more than originally believed.