As predicted, Chevron Corp. has begun laying off staff at the headquarters of the former Unocal Corp., which the San Ramon oil giant purchased for $18 billion after a bitter fight with Chinese oil company CNOOC Ltd.

The numbers are small about 30 of the 130 or so people working at the El Segundo headquarters. More are expected to get the ax at the end of the month, even as others are being offered jobs at Chevron.

“About 90 percent of the Unocal employees had offers to work for Chevron, but most people didn’t take them,” said Unocal spokesman Mike Thacher. “People didn’t want to move to Houston or San Ramon.”

Chevron said it expected to save $325 million by eliminating duplicative operations, with the lion’s share of those savings coming from eliminating employee positions.

Overall, Chevron has announced that 5,000 of Unocal’s 6,400 workers will keep their jobs, while most of the remaining 1,400 will be offered different jobs. Many of Unocal’s employees work in Thailand, Indonesia and elsewhere around the world. Unocal also has marketing and trading offices in Texas, Calgary, Canada, and Singapore.

“They knew nobody would take the jobs,” said analyst Fadel Ghait of Oppenheimer & Co., who called the job offers a symbolic gesture. “Redundancy was absolutely part of the plan. That’s why CNOOC’s offer would have been better for Unocal employees. They promised not to lay people off.”

The lights aren’t all out yet at Unocal’s headquarters. A group of lawyers, accountants and insurance people will stay well into next year to work out retirement and severance issues.

Thacher said most of his communications staff was offered jobs, while company spokesman Barry Lane, the public face of Unocal since the 1970s, will retire. Thacher himself will be looking for a new job.

“We figured we were all dead ducks, but all my staff got offers,” he said. “Not me though. I’m here for three more weeks, then I’m gone.”