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
OMB APPROVAL
OMB Number: 3235-0287
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
WILLIAMSON CHARLES R
  2. Issuer Name and Ticker or Trading Symbol
UNOCAL CORP [UCL]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
CEO
(Last)
(First)
(Middle)
643 SOUTH IRENA AVENUE
3. Date of Earliest Transaction (Month/Day/Year)
08/10/2005
(Street)

REDONDO BEACH, CA 90277
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   107,373 D (2) 0 D  
Common Stock / $1.00 Par Value (1) 08/10/2005   A   308.95 A (3) 8,838.255 I Unocal Savings Plan
Common Stock / $1.00 Par Value (1) 08/10/2005   D   8,838.255 D (4) 0 I Unocal Savings Plan
Common Stock / $1.00 Par Value (1) 08/10/2005   D   26,373 D (5) 0 I Williamson Family Tr. 1/18/95

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number. SEC 1474 (9-02)

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) $ 29.6875 08/10/2005   D     5,548   (7) 03/29/2003 Common Stock / $1.00 Par Value (1) 5,548 (6) 0 D  
Option / (Right to Buy) $ 32.8125 08/10/2005   D     8,000   (8) 03/25/2006 Common Stock / $1.00 Par Value (1) 8,000 (6) 0 D  
Option / (Right to Buy) $ 38.8125 08/10/2005   D     11,600   (9) 03/24/2007 Common Stock / $1.00 Par Value (1) 11,600 (6) 0 D  
Stock Option / (Right to Buy) $ 35.25 08/10/2005   D     100,000   (10) 12/04/2010 Common Stock / $1.00 Par Value (1) 100,000 (6) 0 D  
Stock Option / (Right to Buy) $ 35.355 08/10/2005   D     450,000   (11) 07/27/2011 Common Stock / $1.00 Par Value (1) 450,000 (6) 0 D  
Option / (Right to Buy) $ 49.305 08/10/2005   D     113,475   (12) 02/08/2015 Common Stock / $1.00 Par Value (1) 113,475 (6) 0 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
WILLIAMSON CHARLES R
643 SOUTH IRENA AVENUE
REDONDO BEACH, CA 90277
  X     CEO  

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 for Unocal stock owned, 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 shares is between $6,909,925 and $7,244,982, depending upon the election made and 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 for Unocal stock owned, 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 shares is between $568,781 and $596,360, depending upon the election made and the final election and proration results.
(5) In connection with the Merger, the reporting person is entitled to receive merger consideration in both cash and/or stock of Chevron Corporation for Unocal stock owned, 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 shares is between $1,697,219 and $1,779,516, depending upon the election made and the final election and proration results.
(6) 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.
(7) 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.
(8) The option became exercisable in four equal installments on 9/25/96, 3/25/97, 3/25/98 and 3/25/99
(9) The option became exercisable in four equal installments on 9/24/1997; 3/24/1998; 3/24/1999; and 3/24/2000
(10) The option became exercisable in four equal installments on: 6/4/2001, 12/4/2001, 12/4/2002 and 12/4/2003
(11) 50% became exercisable 7-27-2002; an additional 25% became exercisable 7-27-2003; and the remaining 25% became exercisable 7-27-2004
(12) 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.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.