Ghana is on track to pump its first barrel of crude oil in December from total reserves put at 1.6 billion barrels, Vice President John Dramani Mahama said on Tuesday.

The comments reaffirmed its push to join the league of oil producers this year and the reserve estimate breaks from previous, more cautious forecasts to concur with a top-end figure given by operator Tullow Oil Plc.

"In December this year, Ghana will join the league of petroleum-producing nations as commercial production begins in the Jubilee field," Mahama told a conference in Accra.

"Conservative appraisal of the wells and available statistics based on credible scientific findings indicate that the country holds potentially about 1.6 billion barrels of crude oil," he added, updating previous official forecasts of merely 800 million barrels -- widely considered as overly conservative.

Field operator Tullow puts the upside potential of the core Jubilee Unit Area at one billion barrels of crude, with the southeast section under appraisal at a further 500 million.

Mahama said Ghana could expect oil revenues on average to contribute seven percentage points to annual gross domestic product but warned it would not in itself transform the fortunes of the country, a third of whose people live in poverty.

"Ghana cannot see the oil industry as a miracle wand to solve all problems," he said.

"Rather, the country can prudently use this resource to achieve significant economic turn around," he said, noting plans to base a nascent petrochemicals sector on gas from the field.

Mahama stressed the importance of ensuring local employment in the oil business, which has typically been more capital- than labour-intensive, and said oil revenue management legislation aimed at ensuring transparency was before parliament.

The field is due to take four to six months to reach planned output of 120,000 barrels per day -- a level it will maintain for three years, Ghana's energy minister told Reuters in an interview last month.

KOSMOS' STAKE

Oil firm Kosmos Energy said it had $350 million of extra credit to develop its assets in Ghana's Jubilee field and was committed to staying in Ghana, a week after it said it cancelled an accord to sell its stake to ExxonMobil.

"The funds will support Kosmos' share of Jubilee Field phase one development, appraisal of additional discoveries, and ongoing exploration activities on the West Cape Three Points Block and adjacent Deepwater Tano Block offshore Ghana," it said in a statement issued in Dallas.

Ghana's state petroleum company GNPC -- a fierce opponent of the sale of the Kosmos stake to ExxonMobil for what sources close to the deal put at $4 billion -- last week reiterated its interest in the Kosmos assets.

But the Kosmos statement noted the new funding was part of its plan to build on the value of its assets and repeated that "the company will remain in Ghana".

Kosmos is backed by private equity firms Warburg Pincus and Blackstone Group LP. It is the operator of the West Cape Three Points Block in which it holds a 30.875 percent interest and holds an 18 percent interest in the Deepwater Tano block.