Unocal Corp. Chairman and Chief Executive Charles Williamson received an 86 percent increase in total pay last year to $4.6 million, according to the company’s annual proxy statement filed Monday with the Securities and Exchange Commission.

The bulk of Williamson’s salary in 2004 came from a hefty $2.3 million payout of restricted stock (though he received no restricted stock in 2003). His base salary increased 12 percent to $964,816.

Williamson could potentially receive a handsome payout when Unocal’s acquisition by ChevronTexaco Corp. is completed. He holds 115,902 Unocal shares outright, and has an additional 569,600 common shares underlying stock options exercisable within 60 days from March 15. If he exercised all the options, he would hold 711,875 shares worth an estimated $42 million (before subtracting the exercise price on options).

Earlier this month, Unocal announced its sale to ChevronTexaco, the No. 2 U.S. oil company, for roughly $16.4 billion. On Monday, Unocal shares were trading just below $59, up from around $37 a year earlier.