Oil jumped to $80.05 a barrel on Wednesday, matching its one-year high hit the previous day, after a U.S. government report showed a smaller than expected rise in crude stocks in the world's top consumer.
Crude oil stocks rose 1.3 million barrels in the latest week, the Energy Information Administration said in its report released at 1430 GMT. That was less than the 1.8 million barrel rise expected.
The market is interpreting this report as bullish, but I think crude prices may be rising just because the report didn't contain any bearish surprise, said Gene McGillian, analyst at Tradition Energy in Stamford, Connecticut.
U.S. crude for December rose 50 cents to $79.62 a barrel by 1501 GMT (11:01 a.m. EDT). Brent crude added 66 cents to $77.90.
U.S. crude rose as high as $80.05, equalling the one-year high for a nearby contract the November contact reached on Tuesday before its expiry.
The EIA report also showed that gasoline supplies fell a more than expected 2.3 million barrels and distillate stocks also declined.
Oil also rose as the dollar weakened against a basket of currencies. A falling dollar makes oil relatively cheap to holders of other currencies. The euro rose above $1.50 for the first time since August 2008.
Crude had eased earlier in the session, extending the previous day's retreat from the one-year peak after the American Petroleum Institute said crude stocks rose 3.8 million barrels, more than the forecast.
The EIA report is widely seen as more accurate than the API's because U.S. energy firms are required to participate.
The weak dollar and anticipation of future economic recovery have been among the drivers of the oil price rally this year, rather than market fundamentals of supply, demand and inventories.
The International Energy Agency, which represents 28 industrialized countries, has warned that the fast rise in prices could pose a risk to global economic recovery.
But Nigeria's oil minister, Rilwanu Lukman, said on Wednesday $80 was a fair price for oil and one that should encourage investment in new supplies.
(Additional reporting by Nick Trevethan in Singapore and Reuters energy desk in New York; editing by William Hardy)