press release

Unocal starts production from Moulavi Bazar gas field in Bangladesh

El Segundo, Calif., March 22, 2005 - Unocal Corporation (NYSE: UCL) today said that two of its subsidiaries have started production from the Moulavi Bazar gas field in Bangladesh.

The Moulavi Bazar field is currently producing more than 70 million cubic feet of gas per day (mmcfd), from two well completions. The company plans to complete two more wells by May 2005, which is expected to increase the field's production capacity to 150 mmcfd. The Moulavi Bazar field is located in block 14 in the northeast district of Sylhet. Unocal Bangladesh Blocks 13 and 14, Ltd., is operator and, together with Unocal Bangladesh, Ltd., has a 100-percent working interest in the production sharing contract (PSC) covering the field.

"Production of natural gas from the Moulavi Bazar field is a major milestone toward energy security for Bangladesh," said Andrew L. Fawthrop, president and managing director, Unocal Bangladesh. "The Honorable Prime Minister Begum Khaleda Zia is scheduled to officially inaugurate the plant on April 5. We are extremely pleased to be able to develop the field within budget and the stipulated time frame, helping our partner Petrobangla in its mission of fulfilling Bangladesh energy needs."

Natural gas production from the Moulavi Bazar field is delivered into the existing Bangladesh national gas network. Under the natural gas purchase and sales agreement (GPSA) signed with Petrobangla in October 2003, Unocal built the gas processing plant with a capacity of 150 mmcfd and a 24-kilometer pipeline to connect the field with the national grid. Total development cost of the project, including development wells, has been estimated at US$42 million.

The company estimates the Moulavi Bazar field has a gross resource potential of more than 440 billion cubic feet of gas.

Unocal, through subsidiaries, is producing approximately 200 mmcf of natural gas per day from the Jalalabad Field on block 13 for Petrobangla. With the new production from Moulavi Bazar, gross natural gas production from the fields operated by Unocal Bangladesh for Petrobangla currently totals about 270 million cubic feet of gas per day.

In addition, Unocal has signed a GPSA to develop the Bibiyana field which is expected to add another 200 mmcfd beginning in the fourth quarter 2006. With a total expected investment of $230 million, Unocal estimates that the Bibiyana field could ultimately produce 500 mmcfd by the end of 2009.

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 activities are in Asia and North America.

This news release contains forward-looking statements about matters such as drilling, development and other plans for future operations; production rates and timing; development costs; and assessments of hydrocarbon formations and potential resources. 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 volatility in commodity prices; Unocal's ability to develop and produce fields in a timely and cost-effective manner; the accuracy of Unocal's estimates and judgments regarding hydrocarbon resources and formations and reservoir performance; operational risks inherent in the exploration, development and production of hydrocarbons; international and domestic political and economic factors; and other factors discussed in Unocal's 2004 Annual Report on Form 10-K and subsequent reports filed or furnished by Unocal with the U.S. Securities and Exchange Commission (SEC).

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, www.unocal.com. 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, which is provided pursuant to the safe harbor provisions of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934.

Unocal refers to "resource potential" in this news release. The SEC has generally permitted oil and gas companies, in their filings with the SEC, to disclose only proved reserves that a company has demonstrated by actual production or conclusive formation tests to be economically and legally producible under existing economic and operating conditions. The SEC's guidelines may prohibit Unocal from including in filings with the SEC "resource potential" and similar estimates of hydrocarbon volumes that may be, in whole or in part, potentially recoverable through additional drilling or recovery techniques. These estimates are by their nature more speculative than estimates of proved reserves and accordingly are subject to substantially greater risk of being actually realized. Please refer to Unocal's 2004 Annual Report on Form 10-K for some of the risks and uncertainties in the exploration, development and production of hydrocarbons and for disclosures regarding Unocal's estimates of its proved reserves as of December 31, 2004.

Updated: March 2005