Oil prices rose Monday ahead of the expected restarts at U.S. refineries and Nigerian presidential elections that some fear could spark violence that may disrupt oil supplies.
The tenth consecutive week of draws on U.S. gasoline inventories last week also had potential to exert upward pressure on prices.
Light, sweet crude for May delivery rose 24 cents to US$63.77 a barrel in electronic trading on the New York Mercantile Exchange by midday in Europe. The contract is likely to experience slow trading because it expires this week.
Brent crude for June was up 42 cents at US$68.77 a barrel on London's ICE Futures exchange.
"On a short-term basis we don't really have specific factors" guiding the market, said Tetsu Emori, chief commodities strategist with Mitsui Bussan Futures in Tokyo. "The market is losing direction."
Still, some indicators pointed to an upward trend in the short term.
Last week, oil prices were lifted by problems at several U.S. refineries and a decrease in U.S. gasoline stockpiles. Some, including the McKee refinery in Texas, are expected to resume gasoline production this week, which should support prices.
"We will not know that refinery snag contagion has ended, until it ends. The bullish case is easy to make right now," said John Kilduff at Fimat USA.
Gasoline supplies sank during the first week of April amid strong demand, with stockpiles down 5.5 million barrels to 199.7 million barrels, the U.S. Energy Information Administration reported Wednesday.
Nigerians vote Saturday in presidential elections, a week after at least 21 were killed in violence surrounding state elections. Some fear that the election results could lead to more violence that may disrupt oil supplies in the African nation, the world's eighth-largest exporter and a main supplier of oil to the United States.
Vienna's PVM Oil Associates attributed at least part of the upward trend to "declining U.S. gasoline stocks," adding: "Further support came from Nigeria, with market participants concerned about supply disruptions ahead of the upcoming presidential elections in the country."
In other Nymex trading, heating oil futures were up half a cent at US$1.9060 a gallon while natural gas prices were down 8 cents to US$7.721 per 1,000 cubic feet.