Chevron Corp, the second-largest U.S. oil company, reported a three-fold jump in quarterly profit, beating expectations as refinery margins fattened.

Energy giants such as Chevron and its peers Exxon Mobil Corp and Royal Dutch Shell Plc , which reported earnings on Thursday, have benefited from renewed demand for oil and products such as gasoline and diesel fuel as the global economy crawls out of the deep recession.

Refining and marketing essentially doubled the best expectation that we had, said Oppenheimer & Co analyst Fadel Gheit. When things go well, they go really well.

Chevron's second-quarter net income jumped to $5.4 billion, or $2.70 per share, from $1.75 billion, or 87 cents per share, a year before.

Analysts had been expecting a profit of $2.44 per share, according to the average on Thomson Reuters I/B/E/S. Revenue rose 32 percent to $53 billion.

Chevron has so far felt only a modest impact from the drilling moratorium put in place after the BP Plc spill in the Gulf of Mexico.

But analysts have said the drilling halt could begin to threaten new prospects in the Gulf of Mexico, where Chevron is working on major projects such as Caesar/Tonga, due to start up in 2011.

Shares of Chevron slipped 1 percent to $75.29 in early trade, slightly lagging the 0.8 percent drop in the Chicago Board Options Exchange's oil company index <.OIX>.

SHARE BUYBACK ENDS

The company said it had terminated its three-year $15 billion share repurchase plan that started in September 2007, and put in place an ongoing repurchase plan with no set limits.

Its oil and gas production business reported profit of $4.5 billion, up from $1.66 billion a year ago on both higher volumes and prices.

Global production rose to 2.75 million barrels of oil equivalent per day from 2.67 million barrels, driven by increases in both natural gas and oil output gains.

Chevron's average sales price for oil and other liquids jumped 34 percent from a year ago to $71 per barrel, while its sales price for natural gas climbed 18 percent to $4.40 per thousand cubic feet.

Like others in the industry, Chevron's profit margins at its refineries rose sharply as consumer demand for products such as gasoline and diesel fuel recovered after two years of slack demand. The company posted a profit of $975 million versus $131 million a year ago for that business.

(Reporting by Matt Daily and Braden Reddall in San Francisco, editing by Dave Zimmerman)