press release

Unocal tests successful appraisal well at Gehem field in Kutei Basin offshore Indonesia

El Segundo, Calif., Feb. 25, 2004 - Unocal Corporation (NYSE: UCL) said today its Unocal Ganal, Ltd., subsidiary has drilled a successful appraisal well at the Gehem field in the Ganal production sharing-contract (PSC) area offshore East Kalimantan, Indonesia.

"The Gehem-2 well results show the primary zone of interest to have a single gas column of greater than 550 feet (168 meters)," said David Stangor, president of Unocal Indonesia. "This single zone has the potential to contain up to 1.5 trillion cubic feet of recoverable gas."

A drillstem test (DST) of Gehem-2 flowed at a daily rate of 31.3 million cubic feet of gas and 1,917 barrels of condensate. The zone was perforated from 15,362 feet (4,682 meters) to 15,523 feet (4,731 meters) true vertical depth subsea. The DST had flowing tubing pressure of 6,545 pounds per square inch on a 32/64-inch choke. The test was constrained by test equipment capacity. The oil section was not tested.

The Gehem-2 well was drilled 300 feet (91 meters) downdip of Gehem-1 and encountered 240 feet (73 meters) of net gas pay in zones penetrated by Gehem-1. Beneath those zones, 55 feet (17 meters) of net oil pay was discovered in a single zone. Gehem-2 was drilled in 6,036 feet (1,840 meters) of water to a total vertical depth of 17,505 feet (5,335 meters). The well is located 1.8 miles (2.9 km) south of the Gehem-1 well in the Ganal PSC.

The next well to be drilled in Unocal's deepwater program offshore Indonesia is a deep test on the Gula structure, a large anticline immediately south of Gehem in the Ganal PSC. Following Gula, the company plans to drill Gehem-3 in the second quarter of 2004 to appraise the northwestern flank of the Gehem structure.

Unocal Ganal is operator of the Ganal PSC area and holds an 80-percent working interest. Eni-Ganal, Limited, a subsidiary of Eni (NYSE: E), holds the remaining 20-percent working interest.

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 activities are in North America and Asia.

This news release contains certain forward-looking statements about Unocal's 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 2002 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 2002 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 or from the SEC by calling 800-SEC-0330. The reports are also available on the Unocal web site.

Under the terms of the PSC, Unocal Ganal, Ltd., as contractor to Pertamina, the Indonesia national oil company, is entitled to varying shares of the oil and gas produced from commercial discoveries.

Updated: February 2004