press release

Unocal adds interest in deepwater block offshore Brazil to portfolio

Rio de Janeiro, Brazil - Feb. 19, 2002 - Unocal Corporation (NYSE: UCL) today said that its Unocal do Brasil Ltda. subsidiary has signed an agreement with Esso Explorao Espirito Santo Limitada to acquire a 25-percent non-operating working interest in the exploration block BM-ES-1 in the Espirito Santo basin offshore Brazil.

The block covers 2,700 square-kilometers (670,000 acres) and is approximately 150 kilometers (93 miles) offshore. The water depth ranges from 1,500 to 2,750 meters (4,900 to 9,000 feet).

Esso, operator of the block, holds a 50-percent working interest, while Wintershall BM-ES-1 Limitada has the remaining 25-percent working interest.

"Unocal continues to see opportunity for growth in Brazil," said Dioclcio Arajo, managing director of Unocal do Brasil Ltda. "The BM-ES-1 farm-in demonstrates a continuing commitment to strengthen our current portfolio of assets in Brazil. In addition, we are pleased to be part of this venture with Esso and Wintershall."

With the addition of BM-ES-1 to its portfolio, Unocal now has interests in three exploration blocks in the Espirito Santo basin. Unocal maintains a 40.5-percent operating interest in block BM-ES-2 and a 30-percent non-operating interest in block BES-2. In the Potiguar basin, Unocal holds a 17.5-percent interest in the Pescada-Arabaiana oil and gas project.

About Unocal Corporation

Unocal is one of the world's leading independent natural gas and crude oil exploration and production companies. The company's principal oil and gas operations 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.

Updated: February 2002