press release

Unocal Midstream & Trade holds open season for proposed gas storage capacity at Sabine Pass

Unocal Midstream & Trade holds open season for proposed gas storage capacity at Sabine Pass

Sugar Land, Texas, Oct. 4, 2004 - Unocal Midstream & Trade (UMT), a business unit of a wholly owned subsidiary of Unocal Corporation (NYSE: UCL), announced today that it is conducting a non-binding open season for 6 billion cubic feet (Bcf) of future natural gas storage capacity at its Sabine Pass Gas Storage facility southwest of Beaumont, Texas.

During the open season, which will continue through October 27, 2004, UMT is soliciting expressions of interest in firm gas storage services for all or part of its proposed 6 Bcf of storage capacity. Sabine Pass construction is expected to begin in 2006, with storage operations expected to begin in late 2008.

Sabine Pass, located on Unocal's Big Hill salt dome structure, will be a state-of-the-art natural gas storage facility located 25 miles southwest of Beaumont in Jefferson County, Texas. Plans call for an initial 6 Bcf of natural gas of storage capacity, with 200 million cubic feet per day (MMcf/d) of injection capability and 400 MMcf/d of deliverability.

Sabine Pass is strategically positioned to serve the proposed LNG regasification terminals and current producers along the Texas and Louisiana Gulf Coasts and offshore Louisiana. Proposed bi-directional interconnects to multiple pipelines in the Sabine Pass area will provide access to the Texas intrastate and interstate natural gas markets, Mexican natural gas markets, and the Sabine and Houston Ship Channel industrial corridors.

"This open season will help us size the market demand for Sabine Pass Gas Storage capacity and provide us with information necessary to build sufficient cavern storage to meet the needs of our customers", said Joe Blount, president of Unocal Midstream & Trade. "The development of this greenfield natural gas storage project, much like our successful Keystone Gas Storage facility in West Texas, shows our commitment to establishing UMT as a safe, effective, and efficient developer and operator of underground natural gas storage."

Interested parties wanting to learn more about Sabine Pass' open season process or to obtain an information package should contact Michael Wilems at 281-287-7491 (michael.wilems@unocal.com) or Rex Bigler at 281-287-5513 (rbigler@unocal.com).

About Unocal Midstream & Trade

UMT, a business unit of a wholly owned subsidiary of Unocal Corporation (NYSE: UCL), manages Unocal's storage, pipeline and terminal assets, including interests in 67 Bcf of natural gas storage capacity, more than 8,000 miles of crude oil, natural gas and product pipelines, and 12 million barrels of crude oil and products storage. UMT also markets Unocal's worldwide natural gas, crude oil and condensate resources.

About Unocal Corporation

Unocal is one of the world's leading independent natural gas and crude oil exploration and production companies with principal operations in Asia and North America.

This news release contains forward-looking statements about matters such as Sabine Pass' open season, construction and design plans, storage capabilities, pipeline interconnections and natural gas transportation. Although these statements are based upon Unocal's current expectations and beliefs, they are subject to known and unknown risks and uncertainties that could cause actual results and outcomes to differ materially from those described in, or implied by, the forward-looking statements, including fluctuations in demand for natural gas, receipt of required regulatory approvals, operational and economic factors, performance by third party owners and operators of interconnected pipelines and other risks and uncertainties discussed in Unocal's 2003 Annual Report on Form 10-K, as amended, and other subsequent reports filed by Unocal with the U.S. Securities and Exchange Commission (SEC File No. 1-8483). Copies of Unocal's SEC filings are available from Unocal by calling 800-252-2233 or from the SEC by calling 800-SEC-0330. The reports are also available on the Unocal web site. Unocal undertakes no obligation to update the forward-looking statements in this news release to reflect future events or circumstances. All such statements are expressly qualified by this cautionary statement.

Updated: October 2004