SAN FRANCISCO (AP) _ Chevron Corp. today named a vice chairman, Dave O'Reilly, as its new chairman and chief executive officer, replacing Ken Derr, who is retiring after running the oil company for the last 11 years.

Since Nov. 1998, O'Reilly, 52, has been responsible for Chevron's worldwide exploration and production activities, as well as the effort to cut Chevron's operating costs by $500 million.

``Dave O'Reilly is the right person to lead Chevron in the future,'' said Derr, 63. ``He combines broad company experience with a record of achieving superior business results, and he has strong leadership skills.''

A native of Dublin, Ireland, O'Reilly joined Chevron as an engineer in 1968. By 1989, he became CEO of Chevron's chemical subsidiary. Beginning in 1994, he led Chevron's U.S. refining and marketing operations, whose earnings rose from $75 million in 1995 to $633 million last year.

During Derr's tenure, Chevron has expanded its overseas oil production, cut its operating costs, increased its stock dividends and increased the company's market capitalization from $15 billion to $60 billion, the company said.