Chevron Corp.'s (CVX) first-quarter earnings rose 36% as the second-largest U.S. oil company's results benefited from high oil prices and stronger refining margins.

Shares were down 0.4% at $108.35 in premarket trading as revenue missed analysts' expectations. The stock through Thursday's close is up 32% in the past year.

Chevron, which has been streamlining its downstream business--which deals with refined products--most recently disclosed plans to sell a
U.K. refinery and other assets to Valero Energy Corp. (VLO). The company last year acquired Atlas Energy Inc., a leading producer of natural gas from the Marcellus Shale, one of the many natural-gas-rich rock formations in the U.S. that have led to a surge in production.

Earlier this month, the company said it expected that quarterly exploration and production earnings will be higher, though the gains would be hurt by certain production-sharing contracts.

Chevron, the second-largest
U.S. oil company by market value after Exxon Mobil Corp. (XOM), reported a profit of $6.21 billion, or $3.09 a share, up from $4.55 billion, or $2.27 a share, a year earlier. The latest period included net charges of $388 million, compared with $368 million a year earlier. Revenue climbed 25% to $60.34 billion.

Analysts polled by Thomson Reuters most recently forecast earnings of $3 on revenue of $66.62 billion.

Exploration-and-production earnings rose 27% as production eased 0.7%. Higher oil prices were partly offset by the production decline.

U.S. E&P earnings increased 25% and average daily production dropped 5% amid normal field declines and weather-related maintenance. Average prices for oil and natural-gas liquids climbed 25% while natural gas prices slid 24%.

The company's downstream segment saw earnings more than triple as refining margins strengthened. The company's Chevron's chemical operations also contributed to the improved segment earnings.

Chevron's results echoed those of other oil companies that this week reported surging quarterly profits amid rising oil prices and improved refining margins. Oil giant ConocoPhillips (COP) on Wednesday reported a 44% surge in earnings. On Thursday ExxonMobil posted profit growth of 69% while Occidental Petroleum Corp.'s (OXY) earnings jumped 46%.