Traders said oil prices were also stoked higher by a weakening US dollar and global supply jitters.
"The issue seems no longer to be whether oil will reach 100 dollars per barrel, but when," said Barclays Capital analyst Kevin Norrish.
The price gains in after-hours trading came after New York's main oil futures contract, light sweet crude for delivery in November, had jumped 2.07 dollars to a record close of 89.
47 dollars a barrel.
In electronic trade after the market close, the benchmark contract spiked to an all-time high of 90.
02 dollars.
London prices also pushed higher in after-hours trading, as Brent North Sea crude for December delivery soared to 84.
88 dollars after the contract had earlier settled 1.47 dollars higher at 84.60 dollars.
Oil prices have gained this week amid geopolitical angst, related to fears over a potential conflict affecting Turkey's boder with Iraq, and a weakening dollar.
The dollar's decline has made dollar-priced commodities, such as oil, che