Oil prices rose on Monday as refinery outages in the United States stoked supply concerns again as the end of the summer driving season neared.
U.S. crude traded up 29 cents to $71.38 a barrel by 1:43 p.m. EDT, after jumping $1.26 on Friday. London Brent shed 15 cents to $70.47 a barrel, with trading volumes lighter than normal due to a holiday in Britain.
Gasoline futures got a boost from news of fresh refinery problems in the world's top consumer.
CITGO cut rates at its 156,000-barrel-per-day refinery in Corpus Christi, Texas, after a problem with the alkylation unit, traders said.
Chevron said it expected some shipments to its Pascagoula, Mississippi refinery, one of the 10 biggest in the United States, to be cancelled or rerouted following a fire at a crude unit.
Oil prices have fallen since reaching a record peak of $78.77 on August 1 due to concerns about a global credit crunch and wider economic problems.
Prices eased earlier as traders looked to the end of U.S. summer driving demand, and toward the autumn, when refiners typically build heating oil inventories ahead of the winter.
The failure of hurricane season to produce any protracted outages on the U.S. oil industry so far this year and a steep drop in natural gas prices also helped weaken crude.
I think the Atlantic storm season appears to be a bit of a bust, and with natural gas prices hitting 11-month lows, that is affecting crude prices, said Mike Zarembksi, senior commodities analyst for optionsXpress.
Fresh U.S. economic data showing the housing downturn had intensified also pressured prices in early trade.
OPEC Secretary-General Abdullah al-Badri said on Monday he felt the international oil market was well supplied, suggesting OPEC would keep supplies at current levels when the group next meets on September 11.
Speculators on the New York Mercantile Exchange slashed net long positions in crude oil futures by half to just over 40,000 lots last week, Commodity Futures Trading Commission data showed on Friday.
(Additional reporting by Randy Fabi in London and Fayen Wong in Sydney)