press release

Unocal-led consortium signs agreement with Petrobras for offshore block

El Segundo, Calif., July 30, 1999 - Unocal Corporation announced today that a consortium comprised of Unocal Campos Ltda., Petroleo Brasileiro S.A., Japex Brasil Ltda. (a Brazilian company established by Japan Petroleum Exploration Co., Ltd., and Marubeni Corporation), and YPF BRASIL S.A. signed a participation agreement for block BC-1009, offshore Brazil.

Block BC-1009, comprising 1,400-square-kilometers (346,000 acres), is located in the prolific Campos Basin - currently accounting for about 75 percent of Brazil's hydrocarbon production of 1.1 million barrels of oil per day.

"Unocal is very committed to working in Brazil, and we believe this is a significant opportunity for the consortium," said Sergio Brandao, Unocal's country manager for Brazil.

Unocal is operator of the consortium and has a 35-percent working interest. Petrobras has 35 percent; Japex has 20 percent, while YPF holds the remaining 10 percent.

The consortium could spend US$30-40 million over the next five years for seismic programs and exploratory drilling.

Forward-looking statements regarding future operations, capital spending, and business arrangements in this news release are based on assumptions concerning market, competitive, regulatory, environmental, operational and other considerations. Actual results could differ materially. Actual results could differ materially as a result of factors discussed in Unocal's 1998 Form 10-K report filed with the Securities and Exchange Commission.

Updated: July 1999