Tullow Oil has struck oil in a major new discovery at its well offshore French Guiana, the company said today.

The discovery, which was made at the Zaedyus well in the Guyane Maritime licence, raises the prospect of a major offshore oil producing province in South America.

Drilling encountered 72 metres of net oil pay, and the company said its investigation show the well has encountered good quality reservoir sands.

Tullow has already made discoveries at the Jubilee field in West Africa, and drilling at the the Zaedyus well was intended to find out whether this resource was mirrored on the other side of the Atlantic.

"This discovery therefore opens a new hydrocarbon basin within which several neighbouring prospects have been mapped," Tullow said in a statement.

Tullow has a 27.5 per cent stake in the Guyane Maritime license in partnership with Shell, which has 45 per cent, Total with 24 per cent and Northpet, which has 2.5 per cent.

“The discovery at Zaedyus has proved the extension of the Jubilee-play across the Atlantic and made an important new discovery in French Guiana," said Tullow's exploration director Angus McCoss.

"Tullow has built a commanding and unique acreage position in South America and this result marks the start of a significant and potentially transformational long-term exploration and appraisal campaign in the region.”