New York's main contract, light sweet crude for February delivery, rose 21 cents to $91.32 a barrel in the afternoon.
Brent North Sea crude for February dipped two cents to $97.59.
The closure of Norwegian oil producer Statoil's Snorre and Vigdis fields in the North Sea due to a gas leak was holding crude prices up, said Ong Yi Ling, investment analyst for Phillip Futures in Singapore.
"The shutdown of two North Sea oil fields... incites supply concerns for the market already on edge due to the Alaska pipeline closure," she told AFP.
Snorre produced an estimated 116,000 barrels of oil per day in 2010, the Norwegian Petroleum Directorate said on its website. Vigdis pumped 41,000 barrels of oil per day last year.
The oil field closures dealt a second blow to crude supply in as many weeks following the shutdown of the Trans Alaska Pipeline on January 8.
The suspension of the 800-mile (1,300-kilometre) pipeline's operations -- responsible for delivering 12 percent of US production -- entered its fifth day with no official word on when it would reopen.