Shares of Unocal Corp. surged as much as 22 percent after The Wall Street Journal reported that ChevronTexaco Corp. is considering making a bid for its smaller rival.

The Journal said ChevronTexaco was in the early stages of its deliberations and it was unknown whether it would make a formal bid for the ninth-largest U.S.-based oil and natural gas company.

Shares of El Segundo-based Unocal rose $11.50 to $65 after the opening bell and were trading at $59, up 10.3 percent, by early afternoon in New York.

ChevronTexaco, the second-largest U.S. oil company, may be interested in Unocal to help it keep its oil and gas reserves growing, The Wall Street Journal said.

Unocal’s market value was about $14 billion at the close of trading on Wednesday.

The report comes nearly a month after China National Offshore Oil Corp., China’s top offshore oil and gas producer, was reported to have entered into talks with Unocal.