press release

Unocal announces completion of Lagosta well offshore Brazil

Sugar Land, Texas, Oct. 5, 2001 - Unocal Corporation today announced completion of the Lagosta exploration well located on Block BES-2 offshore Brazil in the Esprito Santo Basin.

Well data collection and evaluation has been completed, and the well has been plugged and abandoned in accordance with Brazilian regulations.

"We are pleased that the well had hydrocarbon shows and that the ANP [Agncia Nacional do Petrleo, Brazil's national petroleum agency] has extended the exploration term for this block for two years," said Dioclcio Arajo, president of Unocal do Brazil. "We will be meeting with the co-venturers to discuss plans for the block in 2002."

Unocal said that further analysis will be required to determine whether or not the prospect can be commercial. The company expects to take a US$18 million pretax charge to earnings in the third quarter 2001 for Unocal's share of costs related to drilling the well.

Unocal holds a 30-percent interest in Block BES-2. Other participants include Petrobras and Mobil Explorao e Desenvolvimento do Brasil Ltda., each with a 35-percent interest.

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 operations are located in North America (Gulf of Mexico region, Alaska and Canada) and in Asia (Thailand, Indonesia, Myanmar, Bangladesh and Azerbaijan). The company is also pursuing exploration programs in West Africa and Brazil.

In Brazil, Unocal, through Brazilian subsidiaries, is operator and holds a 35-percent working interest in Block BC-9, offshore Brazil in the Campos Basin; and, is operator with a 40.5-percent working interest in Block BM-ES-2, offshore Brazil in the Esprito Santo Basin. The company also has an interest in the Pescada Arabaiana oil and gas project in the Potiguar Basin.

This news release contains certain forward-looking statements about Unocal's dry hole expenses and future drilling plans. These statements are not guarantees of future performance. 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 2000 Form 10-K and subsequent reports filed with the Securities and Exchange Commission. . Unocal undertakes no obligation to update the information in this news release.

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.

Updated: October 2001