Hardman managing director Ted Ellyard told corporatefile.com.au the drilling, to begin in August, would begin with an early development well which was expected to confirm the company's reserves figure of 95 million barrels.

"The early development well, planned for drilling in August/September, will be located in a part of the field already incorporated into Hardman's reserve case," Ellyard said.

"Therefore we don't expect a substantial increase ... but the well will provide confidence on the expected production rate for the field."

Mr Ellyard said the estimated capital cost for the Chinguetti field development was $US400 million to first oil production but this would be refined in the next few months as negotiations for production facilities take place. Hardman's bill for the four wells will be $24 million.

"At this stage we're comfortable with the figure and the estimate for Hardman's 21.6 per cent share of $US86 million," Ellyard said.

Mr Ellyard said there had been no discussion about delaying the project following the coup attempt by a minor army faction, which had been quickly suppressed, convincing banks the country remained politically stable.

Partners in the project include operator Woodside 35%, Hardman 21.6%, Italian ENI SpA 35%, Fusion Oil & Gas 6% and Roc Oil 2.4%.