Oil prices jumped more than at $1 to over $71 a barrel on Friday evening as US refinery problems spurred concerns about fuel supplies in the world's top consumer.
US crude for October delivery gained $1.42 to $71.24 a barrel, after a 57 cents gain on Thursday.
London Brent crude rose 89 cents to $70.75 a barrel, after closing at a premium to U.S. oil on Thursday for the first time since July 27.
Traders said Chevron said a fire hit a crude unit at its 325,000 barrel per day Mississippi refinery.
The refinery could be running at 50% for three to four months, traders said.
The news pushed up crude and helped send US petrol futures over 3% higher.
A string of refinery outages during the US summer petrol season have helped support prices in recent months.
Oil has also been sensitive to weakness in world stock markets caused by concerns over the impact of troubles in the US mortgage market on the wider economy.
Financial markets remain nervous about further fall-out from the US mortgage problems that could hurt consumer confidence.
Oil hit a record high of $78.77 a barrel on 1 August, but financial market turmoil caused by the U.S. mortgage sector problems has pushed it lower.
