In morning trade, Brent North Sea crude for October delivery advanced 50 cents to $109.81 a barrel from Tuesday's close of $109.31.

New York's main contract, West Texas Intermediate (WTI) light sweet crude for October delivery added 18 cents to $85.61 a barrel.

Brent is more affected than WTI by the situation in Libya as oil from the North Sea as well as from Libya serve the European markets.

Around 85 percent of Libyan oil output was exported to Europe until the revolt disrupted the country's production six months ago.

Initial euphoria that Libyan oil production will resume pre-crisis levels soon evaporated as it was evident that the North African country will take more time than expected to get its facilities ready for operation.

"The fact that not only is the fighting not over but the realisation that it will take at least a year to get production back to 1.6 million barrels a day, that is having an impact on Brent," said Jim Nicholson, regional vice president with Argus Media energy market news publisher.

Before the uprising began in February, Libya produced about 1.6 million barrels per day and exported 1.3 million, much of it light crude highly valued by Europe's refiners, which have struggled to replace it.

Celebratory fire was heard Wednesday in Tripoli after rebels overran Moamer Kadhafi's compound, despite finding no sign of the Libyan strongman or his sons.

The attack came after three days of fighting in the capital which had left more than 400 killed and 2,000 wounded.

But Kadhafi loyalists still held out in parts of the city, and were in control of the Rixos Hotel, headquarters of the foreign journalists accredited to the regime, preventing any of them from leaving.

Copyright AFP (Agence France-Presse), 2011