Tullow Oil has reported a "significant" oil discovery in Ghana.
It found "significant light oil accumulation" in the offshore Mahogany-1 exploration well on the West Cape Three Points license.
The hole, which has been drilled to a depth of 3,683 metres, "encountered a gross hydrocarbon column of 270 metres with 95 metres of net stacked pay," Tullow said in a drilling statement.
Mahogany-1 will be drilled up to a depth of 4,200 metres.
"Based on evidence to date, ultimate reserves are likely to be materially in excess of previous estimates, with some high-potential zones still to be drilled," said chief executive Aidan Heavey.
Analysts are now estimating the West Cape Three prospect to contain around 300-400 million barrels of oil following the Mahogany-1 discovery.