press release

Unocal completes drilling of Bohr prospect well in Gulf of Mexico

Sugar Land, Texas, March 26, 2003 - Unocal Corporation (NYSE: UCL) today said it has completed drilling operations on the Bohr prospect at Mississippi Canyon block 637 in the deepwater Gulf of Mexico.

The Bohr well has been temporarily abandoned. The well encountered hydrocarbons and evaluation is continuing. Additional analysis and evaluation will be required to determine the potential commerciality of the overall prospect.

Based on the initial understanding from the well, the company said it appears unlikely that the well encountered commercial quantities of oil and gas. Unocal will record a charge for its net expense on the well in the first quarter 2003 results. The company said the earlier dry hole guidance (issued Jan. 29, 2003) of $50 to $60 million overall for the first quarter 2003 remains unchanged. Unocal was operator of the Bohr well and had a 40 percent working interest in the well.

The Discoverer Spirit drillship is now on location to drill an appraisal well on the Champlain prospect on Atwater Valley block 63.

About Unocal Corporation

Unocal is one of the world's leading independent natural gas and crude oil exploration and production companies. The company's oil and gas activities are in North America and Asia.

Updated: March 2003