US oil companies have been awarded most of the contracts on offer at the first open licence auction in Libya.
US companies have been out of Libya for two decades
Companies like Occidental and Chevron Texaco will return to Libya for the first time in more than 20 years.
European oil and gas companies were not awarded any of the licences to explore 127,000 sq km (51,000 sq miles).
Libya - which has Africa's largest oil reserves - is seeking massive foreign investment now that sanctions against Tripoli have been lifted.
Libya produces 1.6m barrels per day at present, but hopes to raise this to 2.1m bpd by the end of the decade.
The latest government licensing programme attracted more than 120 oil companies worldwide but only 63 pre-qualified for the bidding round.
A crowd of 300 black-tied international businessmen waited for the envelopes to be opened and their bids examined and compared before Libya's national oil company announced the winners of each bloc, reports the BBC's Rana Jawad from Tripoli.
In his opening remarks, Libyan Prime Minister Shukri Ghanim said both the government and the oil companies must be carry on business honestly.
"Transparency does not mean it should be on our side alone," he said. "It must also be the obligation on the side of the companies that they should be transparent."
Occidental, in conjunction with different consortiums, had a total of nine successful bids.
The overall result came as no surprise to the chairman of Libya's national oil company, Abdul al-Badri, who said local knowledge had paid off.
"Maybe Occi they know the country, they know the basins that they bid," he said.
"As you can see, some of the blocs they bid very high because maybe they don't have geological information; and some of the blocs they bid very low because they have some technical information."
Occidental acquired five licences bidding alone, and another in conjunction with the Australian company, Woodside Petroleum Ltd.
ChevronTexaco will explore the Marzouk basin south of Tripoli, with Amerada Hess being the other US company to win a licence. India Ltd and India Corp won the bid for the Syrte region.
Canada's Verenex Energy Inc, Algeria's Sonatrach, Medco Energy International of Indonesia, United Arab Emirates' Liwa and Brazil's Petrobras were also successful.
The notable losers in this auction round were the European oil and gas companies who went home with nothing.
Mr al-Badri said another 40 blocks would be offered at a second auction next month.