Feb. 11 (Bloomberg) -- Crude oil rose to a one-month high after Valero Energy Corp. shut its Delaware refinery because of a storm-related power failure yesterday and cold weather moved across the northern U.S.

Valero, the biggest U.S. refining company, said it is starting units at the Delaware City plant today. Citgo Petroleum Corp.'s Lake Charles, Louisiana, refinery is starting units after a ``partial power failure'' yesterday. Oil also rose as the coldest weather of the winter moved into the U.S. Northeast.

``The Valero story is heightening nervousness about the refining industry,'' said Nauman Barakat, senior vice president of global energy futures at Macquarie Futures USA Inc. in New York. ``The big worry is that there will be a slew of problems as we prepare for the driving season this spring.''

Crude oil for March delivery rose $1.82, or 2 percent, to settle at $93.59 a barrel at 2:46 p.m. on the New York Mercantile Exchange, the highest close since Jan. 14. Futures are down 6.5 percent since touching a record $100.09 a barrel on Jan. 3.

Brent crude for March settlement rose $1.59, or 1.7 percent, to settle at $93.53 a barrel on London's ICE Futures Europe exchange. It was the highest close since Jan. 9. Brent touched a record $98.50 on Jan. 3.

Valero's Delaware City refinery can process 190,200 barrels of oil a day, according to U.S. Energy Department and company data. Citgo's Lake Charles refinery had the capacity to process 454,500 barrels of oil a day as of January.

U.S. refiners make repairs and upgrades during the lull in demand between the end of the heating season and the beginning of the driving season. Refineries probably operated at 84.3 percent of capacity last week, unchanged from the week before, according to a Bloomberg News survey. Refineries in the week ended Feb. 1 operated at the lowest rate since March 2006.

`We've Been Lucky'

``Temperatures have been very moderate so far this winter,'' said Brad Samples, commodity analyst for Summit Energy Inc. in Louisville, Kentucky. ``We've been lucky because heating-oil stocks were low at the start of the season. With all of the refinery utilization occurring, we can expect to see further inventory drops.''

The temperature in New York is forecast to plunge to 16 degrees Fahrenheit (minus 9 Celsius) tonight, 11 degrees below normal, the National Weather Service said.

Heating oil for March delivery rose 5.03 cents, or 2 percent, to $2.6044 a gallon in New York, the highest close since Jan. 9. Gasoline for March delivery climbed 3.9 cents, or 1.7 percent, to $2.3962 a gallon, the highest close since Jan. 9.

Venezuelan President Hugo Chavez threatened to halt oil exports to the U.S. after Exxon Mobil Corp. took action to freeze $12 billion of oil assets.

`Mr. Danger'

``Listen to me, Mr. Bush, Mr. Danger. If the economic war continues against Venezuela, the price of oil will reach $200. Venezuela will take up the economic war and more than one country is inclined to join us,'' Chavez said yesterday during his weekly television show.

Exxon's move may cut into Chavez's popularity by forcing him to cut back spending. Venezuela counts on oil income for 90 percent of its foreign exchange and half of federal tax revenue.

``The Exxon news came on Friday and he waited till today to respond,'' said Pedro Benitez, an oil consultant and political economy professor at the Central University of Venezuela in Caracas. ``Why not talk in the last three days? This is about maximizing the impact on the oil market.''

Venezuela was the fourth-biggest source of U.S. crude-oil imports during the first 11 months of 2007, according to the Energy Department.

``Supply threats abound at the moment, both real and imagined,'' said John Kilduff, vice president of risk management at MF Global Ltd. in New York. ``Violence in Nigeria looks to worsen after this latest round and while it may be empty rhetoric on the part of Hugo Chavez, you also must consider that he is capable of anything. The geopolitical risk is being reinflated.''

Vessel Attacks

Nigeria LNG Ltd. said a naval vessel escorting the company's staff boat came under fire today, killing one sailor, a spokeswoman said. A vessel operated by Total SA was also attacked prior to the shooting, said Siene Allwell-Brown, a spokeswoman for Nigeria LNG.

Nigerian production has been slashed by about 500,000 barrels a day over the past two years because of attacks on facilities. Nigeria produces low-sulfur, or sweet, crude oil, prized by U.S. refiners because of the proportion of high-value gasoline it yields.

To contact the reporter on this story: Mark Shenk in New York at mshenk1@bloomberg.net.

Last Updated: February 11, 2008 15:58 EST