London Brent crude futures hit $50 a barrel for the first time today, extending a relentless rise that has added around 65 per cent to the cost of crude this year.
Brent for November delivery on London's International Petroleum Exchange was up 29 cents on the session.
US light, sweet crude oil futures were hovering near last week's all-time high of $53.40 a barrel, trading down 3 cents at $53.28 this morning.
Spare production capacity among OPEC members has been eroded this year by strong demand growth from China and elsewhere, leaving the global market little flexibility to cope with the type of disruptions now dragging on in the United States.
"The main driver these days is the fact that world spare capacity is so low," said Mr David Thurtell at Commonwealth Bank of Australia in Sydney. "It's never been this low and that means that we're in uncharted territory."
About 475,000 barrels per day (bpd) of US Gulf of Mexico oil production remains out of commission, nearly four weeks after Hurricane Ivan struck the region.
More supplies to the United States were disrupted by weather at the weekend, as Tropical Storm Matthew forced the closure of the massive Louisiana Offshore Oil Port on Friday.