EXHIBIT 99.1

                                              UNOCAL
                                              2141 Rosecrans Avenue, Suite 4000
                                              El Segundo, California 90245

                                  [UNOCAL LOGO]

                                              NEWS RELEASE

                                              Contact: Barry Lane (News media)
                                                       310-726-7665
                                                       Robert Wright (Investors)
                                                       310-726-7665

          UNOCAL RECEIVES MERGER PROPOSAL FROM CNOOC FOR $67 PER SHARE


       El Segundo, Calif., June 22, 2005 - Unocal Corporation (NYSE: UCL) today
said it has received a proposal from CNOOC Limited, an affiliate of China
National Offshore Oil Company, to acquire all outstanding shares of Unocal for
$67 per share in cash.
       On April 4, 2005, Unocal agreed to be acquired by Chevron Corporation in
a merger that offers Unocal stockholders an election, subject to proration,
between $65 in cash, 1.03 shares of Chevron common stock and a combination of
cash and Chevron common stock for each Unocal share.
       In connection with entering into the Chevron merger agreement, the Unocal
board of directors recommended the transaction to Unocal stockholders. That
recommendation remains in effect.
       Unocal said that it intends to evaluate the CNOOC proposal in a manner
consistent with the board's fiduciary duties and its obligations under the
Chevron agreement. Unocal also said that there can be no assurance that the
proposal would result in a definitive agreement with CNOOC.

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 North America and Asia. For additional information about
Unocal's global activities, visit the company's web site at www.unocal.com.







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ADDITIONAL INFORMATION FOR INVESTORS
Chevron has filed a preliminary Form S-4, Unocal will file a proxy statement and
both companies will file other relevant documents concerning the proposed merger
transaction with Chevron with the Securities and Exchange Commission (SEC).
INVESTORS ARE URGED TO READ THE FORM S-4, PROXY STATEMENT AND ANY OTHER RELEVANT
DOCUMENTS FILED WITH THE SEC BECAUSE THEY CONTAIN IMPORTANT INFORMATION. You may
obtain the documents free of charge at the Web site maintained by the SEC at
www.sec.gov. In addition, you may obtain documents filed with the SEC by Chevron
free of charge by contacting Chevron Comptroller's Department, 6001 Bollinger
Canyon Road - A3201, San Ramon, CA 94583-2324. You may obtain documents filed
with the SEC by Unocal free of charge by contacting Unocal Stockholder Services
at (800) 252-2233, 2141 Rosecrans Avenue, Suite 4000, El Segundo, CA 90245.

Chevron, Unocal, and their respective directors and executive officers, may be
deemed to be participants in the solicitation of proxies from Unocal's
stockholders in connection with the proposed Chevron merger. Information about
the directors and executive officers of Chevron and their ownership of Chevron
stock is set forth in the proxy statement for Chevron's 2005 Annual Meeting of
Stockholders. Information about the directors and executive officers of Unocal
and their ownership of Unocal stock is set forth in the proxy statement for
Unocal's 2005 Annual Meeting of Stockholders. Investors may obtain additional
information regarding the interests of such participants by reading the Form S-4
and proxy statement for the merger.

Investors should read the Form S-4 and proxy statement carefully before making
any voting or investment decisions.

CAUTIONARY INFORMATION REGARDING FORWARD-LOOKING STATEMENTS
Except for the historical and factual information contained herein, the matters
set forth herein, including statements as to the proposed merger transaction
with Chevron, the CNOOC proposal and other statements identified by words such
as "estimates," "expects," "projects," "plans," and similar expressions are
forward-looking statements within the meaning of the "safe harbor" provisions of
the Private Securities Litigation Reform Act of 1995. These forward-looking
statements are subject to risks and uncertainties that may cause actual results
to differ materially, including uncertainties as a result of the CNOOC proposal
and other risk factors as detailed from time to time in Unocal's reports filed
or furnished with the SEC, including Unocal's most recent Annual Report on Form
10-K. You should not place undue reliance on these forward-looking statements,
which speak only as of the date of this press release. Unless legally required,
Unocal undertakes no obligation to update publicly any forward-looking
statements herein, whether as a result of new information, future events or
otherwise.

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