press release

Unocal, PTT reach agreement to extend gas contract, revise pricing

El Segundo, Calif., March 27, 2002 - Unocal Corporation (NYSE: UCL) today said its Unocal Thailand, Ltd., subsidiary has reached agreement with PTT Plc to extend the gas sales agreement (GSA) for the Erawan field by five-and-one-half years to 2012.

The parties also agreed to discount the average sales price of gas from GSA 1, 2 and 3. The discount for GSA 1 (Erawan) will become effective in July 2002; for GSA 2 and 3, the discount is effective in October. These three GSAs account for 82 percent of the daily contract minimum for the Unocal-operated fields in Thailand.

For 2003-2012, Unocal's sales price will be discounted by about 5 cents per mcf, or 2 percent. The current expected realized price for all of Unocal's Thailand GSAs in 2002 is about $2.45 per mcf.

"This agreement allows us to continue our long-term relationship with the Kingdom of Thailand and make the capital investments needed to develop additional resources in the Erawan, Baanpot and Dara gas fields," said Randy Howard, president of Unocal Thailand.

Unocal has said it expects gross capital expenditures in Thailand of approximately US$4.3 billion (186 billion baht) over the next 10 years.

"The natural gas from Erawan and other Unocal-operated fields provides significant electrical generation cost savings for Thailand and an economical source of clean fuel for the Kingdom into the next decade," Howard said.

"Thailand's natural gas resources give the Kingdom a definite competitive advantage in producing of electricity, as well as providing additional benefits to Thailand through royalties, taxes and domestic employment," Howard said.

Unocal holds a 70-percent net working interest in GSA 1, and 62-percent net working interests in GSA 2 and 3. Co-concessionaires are Mitsui Oil Exploration Co., Ltd., and PTT Exploration and Production PCL.

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, Asia, Latin America, the North Sea, and West Africa. Unocal is one of the world's largest producers of geothermal energy with operations in the Philippines and Indonesia.

This news release contains certain forward-looking statements about Unocal's future sales prices, capital expenditures and development plans. The statements are based upon Unocal's current expectations and beliefs and are subject to a number of known and unknown risks and uncertainties that could cause actual results to differ materially from those described in the forward looking statements. Actual results could differ materially as a result of factors discussed in Unocal's 2001 Annual Report on Form 10-K and subsequent reports filed with the Securities and Exchange Commission.

U.S. investors are urged to consider closely the disclosure in Unocal's 2001 Annual Report on Form 10-K (SEC File No. 1-8483). Copies of the company's SEC filings are available from the company by calling 800-252-2233. The reports are also available on the Unocal web site, www.unocal.com. You can also obtain this form from the SEC by calling 800-SEC-0330.

Updated: March 2002