SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549



                                    FORM 8-K



                             Current Report Pursuant
                          to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934



    Date of report (Date of earliest event reported)        August 20, 2002
                                                        ------------------------



                               UNOCAL CORPORATION
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             (Exact name of registrant as specified in its charter)



                                    Delaware
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                 (State or Other Jurisdiction of Incorporation)



    1-8483                                   95-3825062
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(Commission File Number)                (I.R.S. Employer Identification No.)



2141 Rosecrans Avenue, Suite 4000, El Segundo, California         90245
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(Address of Principal Executive Offices)                       (Zip Code)



                                 (310) 726-7600
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              (Registrant's Telephone Number, Including Area Code)



Item 5.      Other Events.

The Company issued the following press release on August 20, 2002:

Unocal announces offer to acquire outstanding stock of Pure Resources
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     El Segundo,  Calif.,  Aug. 20, 2002 -- Unocal Corporation (NYSE: UCL) today
said its board of directors  has approved  plans for its  subsidiary,  Union Oil
Company of California,  to make an offer to the  stockholders of Pure Resources,
Inc.  (NYSE:  PRS) to acquire all of the  outstanding  shares of common stock of
Pure that Unocal does not already own.

     Pure  stockholders will be offered 0.6527 shares of Unocal common stock, in
an exchange designed to be tax-free, for each outstanding share of Pure's common
stock they own. Unocal would issue  approximately  12 million shares to complete
the transaction.

     Unocal,  through its  subsidiary  Union Oil of  California,  currently owns
approximately  65 percent of Pure's  common stock.  Based on the $34.09  closing
price of Unocal's  shares on Aug.  20,  2002,  the offer  represents  a value of
approximately  $22.25 per share of Pure common stock and a 27-percent premium to
the closing price of Pure common stock on that date.

     Unocal expects to file offering  materials with the Securities and Exchange
Commission  and to  commence  its  exchange  offer on or about  Sept.  5,  2002.
Unocal's  offer  will be  subject  to the  condition  that it  holds at least 90
percent of the outstanding  shares of Pure common stock at the completion of the
exchange offer and other customary conditions.

     Following successful completion of the exchange offer, Unocal will effect a
short-form  merger of Pure with a subsidiary of Unocal in which Pure shares held
by  the  remaining  public   stockholders   will  be  converted  into  the  same
consideration  paid in the exchange  offer,  except for those  stockholders  who
exercise appraisal rights.

About Unocal Corporation

     Unocal is one of the world's leading  independent natural gas and crude oil
exploration and production  companies.  The company's oil and gas activities are
in North America,  Asia, Latin America,  and the North Sea. Unocal is one of the
world's  largest   producers  of  geothermal   energy  with  operations  in  the
Philippines and Indonesia.

About Pure Resources, Inc.

     Pure is an independent exploration and production company that develops and
produces oil and natural gas in the Permian Basin,  the San Juan Basin, the Gulf
Coast and the Gulf of Mexico.  The company also owns an undivided interest under
approximately  6 million  gross fee mineral acres  throughout  the Southern Gulf
Coast region of the U.S. Pure was formed in May 2000 through the  combination of
Titan  Exploration,  Inc.,  and  the  Permian  Basin  business  unit  of  Unocal
Corporation.

                                      -1-

Additional information and where to find it

     In  connection  with the proposed  transaction,  Unocal  expects to file an
exchange offer prospectus and related materials with the Securities and Exchange
Commission.  These materials will contain important  information.  Investors and
security  holders are advised to  carefully  review  this  document  and related
materials when they become available.

     Investors and security holders may obtain a free copy of the exchange offer
prospectus  and other  documents  filed by  Unocal  with the  commission  at the
commission's web site, www.sec.gov.  Copies of the exchange offer prospectus, as
well as Unocal's related filings made with the Commission,  may also be obtained
from Unocal's Investor Relations Department at 310-726-7667.

Conference call

     Unocal will hold a conference  call with financial  analysts to discuss the
offer. The call will be held on Wednesday, Aug. 21, 2002, at 8 a.m. PDT (11 a.m.
EDT).

     To listen to the  conference  call over the  Internet,  go to the  Investor
Information section of the Unocal web site,  www.unocal.com.  To dial-in for the
call, the number is 888-810-8159 or 312-470-7113,  passcode 9836. Replays of the
conference  call,  including  questions and answers,  will be available  through
Sept. 20, 2002.

                                  * * * * *

This news  release  contains  certain  forward-looking  statements  about future
business  transactions  involving  Unocal  and Pure.  These  statements  are not
guarantees of future  performance  and involve  certain risks and  uncertainties
that are difficult to predict.  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 from what is expressed or forecasted in this news release. Those risk
factors are  discussed  in the Unocal and Pure  Annual  Reports on Form 10-K and
subsequent  reports  that  have  been  filed  by the  companies  with  the  U.S.
Securities and Exchange Commission.

NEWSLINE,  produced  for  employees  by  PR &  Communications,  is  archived  on
SeventySix Online at http://st.unocal.com/76.

                                      -2-



Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.




                                                 UNOCAL CORPORATION
                                                   (Registrant)




Date:  August 22, 2002                        By:  /s/ JOE D. CECIL
      ------------------                         -------------------------------
                                                  Joe D. Cecil
                                                  Vice President and Comptroller



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