London - World oil prices slid on Thursday as investors nervously awaited this week's crucial speech from Federal Reserve chairman Ben Bernanke.
Brent North Sea crude for delivery in October dropped 26 cents to $112.28 a barrel in late afternoon London deals.
New York's main contract, West Texas Intermediate (WTI) light sweet crude for October, retreated $1.53 to $93.96 a barrel.
Attention is now on a meeting of central bankers at Jackson Hole, Wyoming, where Bernanke is due to give a speech on Friday, with investors hoping he will outline plans for another round of monetary easing to kickstart the US economy.
"Crude oil prices remain in consolidation mode today, stuck in narrow ranges along with the broader commodity complex as markets continue to tread water ahead of Bernanke's Jackson Hole speech," said Sucden analyst Jack Pollard.
He added: "WTI's relative weakness thus far ... reflects an easing in storm damage concerns to offshore Gulf platforms following Hurricane Isaac's landfall yesterday."
"The weather conditions should keep north Gulf production limited for the remainder of the week, though the chance of permanent damage appears to have reduced."
Supply concerns eased Thursday after Hurricane Isaac left production facilities in the US Gulf of Mexico relatively unscathed, analysts said.
Fears about disruption to supply in the US Gulf from Hurricane Isaac had depressed prices but in the end proved unfounded, said Sanjeev Gupta, who heads the Asia-Pacific oil and gas practice at Ernst and Young.
"Most of the production facilities were shut down in advance of the storm, but early reports indicated fairly limited supply disruptions, thus taking some of the pressure off prices," he told AFP.
The Gulf of Mexico is the hub of US offshore energy production, accounting for 23% of crude oil output and 7% for natural gas.
The Gulf coast's facilities also have more than 40% of total US petroleum refining capacity and 30% of natural gas processing plant capacity.