Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
BRIFFETT JOHN A
  2. Issuer Name and Ticker or Trading Symbol
UNOCAL CORP [UCL]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Vice President and Comptroller
(Last)
(First)
(Middle)
1450 CABALLERO RD
3. Date of Earliest Transaction (Month/Day/Year)
08/10/2005
(Street)

ARCADIA, CA 91006
4. If Amendment, Date Original Filed(Month/Day/Year)
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock / $1.00 Par Value (1) 08/10/2005   D   8,648 D (2) 0 D  
Common Stock / $1.00 Par Value (1) 08/10/2005   A   111.66 A (3) 6,195.542 I Unocal Savings Plan (401-K)
Common Stock / $1.00 Par Value (1) 08/10/2005   D   6,195.542 D (4) 0 I Unocal Savings Plan (401-K)

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Option / (Right to Buy) $ 36.26 08/10/2005   D     5,599   (6) 02/12/2011 Common Stock / $1.00 Par Value (1) 5,599 (5) 0 D  
Option / (Right to Buy) $ 34.725 08/10/2005   D     3,280   (7) 02/12/2012 Common Stock / $1.00 Par Value (1) 3,280 (5) 0 D  
Option / (Right to Buy) $ 27.07 08/10/2005   D     4,322   (8) 02/11/2013 Common Stock / $1.00 Par Value (1) 4,322 (5) 0 D  
Option / (Right to Buy) $ 36.869 08/10/2005   D     5,154   (9) 02/10/2014 Common Stock / $1.00 Par Value (1) 5,154 (5) 0 D  
Option / (Right to Buy) $ 49.305 08/10/2005   D     4,583   (10) 02/08/2015 Common Stock / $1.00 Par Value (1) 4,583 (5) 0 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
BRIFFETT JOHN A
1450 CABALLERO RD
ARCADIA, CA 91006
      Vice President and Comptroller  

Signatures

 Paul R Moore, Asst Secretary, Attorney-In-Fact   08/12/2005
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Pursuant to the Agreement and Plan of Merger among Unocal Corporation, Chevron Corporation and Blue Merger Sub Inc. (the "Merger Agreement"), each share of Unocal Corporation Common Stock issued and outstanding immediately prior to the effectiveness of the merger on August 10, 2005 (the "Merger"), together with the Preferred Stock Purchase Rights attached thereto, was converted into the right to receive the merger consideration specified in the Merger Agreement.
(2) In connection with the Merger, the reporting person is entitled to receive merger consideration in both cash and/or stock of Chevron Corporation, subject to election and proration. Based on a press release issued by Chevron on August 10, 2005 announcing preliminary results of elections for merger consideration, and valuing Chevron shares at the closing price of $62.48 on August 10, 2005, the estimated value of the merger consideration to be received by the reporting person in exchange for these Unocal shares is between $556,537 and $583,523, depending upon the election made and any the final election and proration results.
(3) Shares are purchased at prevailing market prices by the trustee of the Unocal Savings Plan.
(4) In connection with the Merger, the reporting person is entitled to receive merger consideration in both cash and/or stock of Chevron Corporation, subject to election and proration. Based on a press release issued by Chevron on August 10, 2005 announcing preliminary results of elections for merger consideration, and valuing Chevron shares at the closing price of $62.48 on August 10, 2005, the estimated value of the merger consideration to be received by the reporting person in exchange for these Unocal shares is between $398,710 and $418,044, depending upon the election made and the final election and proration results.
(5) This option was assumed by Chevron Corporation pursuant to the Merger Agreement, and converted into an option to purchase a revised number of Chevron Corporation common shares (determined by multiplying the number of shares of Unocal Common Stock subject to the option by the Stock Award Exchange Ratio, rounded down to the nearest whole share) at a new exercise price (determined by dividing the exercise price per share of Unocal Common Stock subject to the option by the Stock Award Exchange Ratio, rounded up to the nearest one hundredth of a cent). The Stock Award Exchange Ratio is 1.0688331.
(6) The option became exercisable in four equal installments on 8/12/01, 02/12/02, 02/12/03, and 02/12/04
(7) The option became exercisable in four equal installments on 8/12/2002, 2/12/2003, 2/12/2004 and 2/12/2005.
(8) The option was originally scheduled to become exercisable in four equal installments on 8/11/2003; 2/11/2004; 2/11/2005; and 2/11/2006. The entire option became exercisable upon effectiveness of the merger on 8/10/2005.
(9) The stock option was originally scheduled to become exercisable in three equal annual installments on 2-10-2005, 2-10-2006 and 2-10-2007. The entire option became exercisable upon effectiveness of the merger on August 10, 2005.
(10) The option was originally scheduled to become exercisable in three equal installments on 2/8/2006, 2/8/2007 and 2/8/2008. The entire option became exercisable upon the effectiveness of the merger August 10, 2005.

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