SEC FORM 3/A

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

ANADARKO PETROLEUM CORP

(Last)

(First)

(Middle)

1201 LAKE ROBBINS DR.

(Street)

THE WOODLANDS

77380

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
06/22/2006

3. Issuer Name and Ticker or Trading Symbol
WESTERN GAS RESOURCES INC [ WGR ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

Director	X	10% Owner
Officer (give title below)		Other (specify below)

5. If Amendment, Date of Original Filed (Month/Day/Year)
06/29/2006

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	0⁽¹⁾	I⁽¹⁾	See Footnote (1 & 2)⁽²⁾

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)

Explanation of Responses:

1. This Form 3 is being filed as a result of certain Voting Agreements covering 13,900,602 shares (the "Shares") of common stock of Western Gas Resources, Inc. ("Western Gas") entered into on June 22, 2006 between Anadarko Petroleum Corporation ("Anadarko") and each of Dean Phillips, Bill M. Sanderson and Mabeth Sanderson, Cedar Assets Trust, James A. Senty, Roswitha Stonehocker, Walter L. Stonehocker, Brion Wise, John F. Chandler, and Peter A. Dea as part of a proposed acquisition of Western Gas by Anadarko. The Shares include 749,464 shares that are issuable upon the exercise of outstanding stock options that are exercisable within 60 days of the date of the Voting Agreements.

2. For additional information regarding the Voting Agreements and the acquisition of Western Gas by Anadarko, see the Schedule 13D filed by Anadarko with the Securities and Exchange Commission on June 29, 2006. Anadarko expressly disclaims any beneficial ownership of the Shares. Anadarko has no "pecuniary interest" in the Shares.

	/s/Charlene A. Ripley, Vice President, General Counsel, Corporate Secretary and Chief Compliance Officer	07/05/2006
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (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).
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