Filing Details

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1	NAMES OF REPORTING PERSONS
	Occidental Petroleum Corporation
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			200,281,578*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			200,281,578*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	200,281,578*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	49.0%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	HC; CO

* Represents (i) 161,319,520 common units representing limited partner interests in the Issuer (“Common Units”) held by Western Gas Resources, Inc. (“WGRI”), (ii) 457,849 Common Units held by APC Midstream Holdings, LLC (“AMH”), (iii) 14,364,949 Common Units held by Anadarko USH1 Corporation (“AUSH1”) and (iv) 24,139,260 Common Units held by WGR Asset Holding Company LLC (“WGRAH”). Occidental Petroleum Corporation (“Occidental”) indirectly owns 100% of the issued and outstanding common stock of Anadarko Petroleum Corporation (“Anadarko”), which directly or indirectly owns 100% of the issued and outstanding equity interests of WGRI, AMH, AUSH1 and WGRAH. Occidental may, therefore, be deemed to beneficially own the Common Units held by WGRI, AMH, AUSH1 and WGRAH.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	OXY USA Inc.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			200,281,578*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			200,281,578*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	200,281,578*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	49.0%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	CO

* Represents (i) 161,319,520 Common Units held by WGRI, (ii) 457,849 Common Units held by AMH, (iii) 14,364,949 Common Units held by AUSH1 and (iv) 24,139,260 Common Units held by WGRAH. OXY USA Inc. indirectly owns 100% of the issued and outstanding common stock of Anadarko, which directly or indirectly owns 100% of the issued and outstanding equity interests of WGRI, AMH, AUSH1 and WGRAH. OXY USA Inc. may, therefore, be deemed to beneficially own the Common Units held by WGRI, AMH, AUSH1 and WGRAH.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	Occidental Permian Manager LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			200,281,578*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			200,281,578*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	200,281,578*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	49.0%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	OO - limited liability company

* Represents (i) 161,319,520 Common Units held by WGRI, (ii) 457,849 Common Units held by AMH, (iii) 14,364,949 Common Units held by AUSH1 and (iv) 24,139,260 Common Units held by WGRAH. Occidental Permian Manager LLC may be deemed to beneficially own the Common Units held by WGRI, AMH, AUSH1 and WGRAH.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	OXY Oil Partners, Inc.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			0
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	0
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	0
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	HC; CO

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	Oxy USA WTP LP
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			200,281,578*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			200,281,578*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	200,281,578*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	49.0%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	PN - limited partnership

*Represents (i) 161,319,520 Common Units held by WGRI, (ii) 457,849 Common Units held by AMH, (iii) 14,364,949 Common Units held by AUSH1 and (iv) 24,139,260 Common Units held by WGRAH. Oxy USA WTP LP is the manager of New OPL, LLC, which indirectly owns 100% of the issued and outstanding common stock of Anadarko, which directly or indirectly owns 100% of the issued and outstanding equity interests of WGRI, AMH, AUSH1 and WGRAH. Oxy USA WTP LP may, therefore, be deemed to beneficially own the Common Units held by WGRI, AMH, AUSH1 and WGRAH.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	New OPL, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			200,281,578*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			200,281,578*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	200,281,578*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	49.0%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	OO - limited liability company

* Represents (i) 161,319,520 Common Units held by WGRI, (ii) 457,849 Common Units held by AMH, (iii) 14,364,949 Common Units held by AUSH1 and (iv) 24,139,260 Common Units held by WGRAH. New OPL, LLC indirectly owns 100% of the issued and outstanding common stock of Anadarko, which directly or indirectly owns 100% of the issued and outstanding equity interests of WGRI, AMH, AUSH1 and WGRAH. New OPL, LLC may, therefore, be deemed to beneficially own the Common Units held by WGRI, AMH, AUSH1 and WGRAH.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	Baseball Merger Sub 2, Inc.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			200,281,578*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			200,281,578*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	200,281,578*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	49.0%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	HC; CO

* Represents (i) 161,319,520 Common Units held by WGRI, (ii) 457,849 Common Units held by AMH, (iii) 14,364,949 Common Units held by AUSH1 and (iv) 24,139,260 Common Units held by WGRAH. Baseball Merger Sub 2, Inc. indirectly owns 100% of the issued and outstanding common stock of Anadarko, which directly or indirectly owns 100% of the issued and outstanding equity interests of WGRI, AMH, AUSH1 and WGRAH. Baseball Merger Sub 2, Inc. may, therefore, be deemed to beneficially own the Common Units held by WGRI, AMH, AUSH1 and WGRAH.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

CUSIP No.: 958669 103

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	Anadarko Holding Company
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Utah
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			14,364,949*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			14,364,949*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	14,364,949*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	3.5%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	HC; CO

* Represents 14,364,949 Common Units held by AUSH1.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	Western Gas Resources, Inc.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			185,916,629*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			185,916,629*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	185,916,629*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	45.5%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	HC; CO

* Represents (i) 161,319,520 Common Units held by WGRI, (ii) 457,849 Common Units held by AMH and (iii) 24,139,260 Common Units held by WGRAH. In addition to its Common Units held of record, WGRI directly or indirectly owns 100% of the issued and outstanding equity interests of AMH and WGRAH and may, therefore, be deemed to beneficially own the Common Units held by AMH and WGRAH.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	APC Midstream Holdings, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			24,597,109*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			24,597,109*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	24,597,109*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	6.0%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	OO - limited liability company

* Represents (i) 457,849 Common Units held by AMH and (ii) 24,139,260 Common Units held by WGRAH. In addition to its Common Units held of record, AMH directly owns 100% of the issued and outstanding equity interests of WGRAH and may, therefore, be deemed to beneficially own the Common Units held by WGRAH.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	WGR Asset Holding Company LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			24,139,260*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			24,139,260*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	24,139,260*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	5.9%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	OO - limited liability company

* Represents 24,139,260 Common Units held of record by WGRAH.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	Kerr-McGee Worldwide Corporation
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			14,364,949*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			14,364,949*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	14,364,949*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	3.5%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	HC; CO

* Represents 14,364,949 Common Units held by AUSH1.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

CUSIP No.: 958669 103

1	NAMES OF REPORTING PERSONS
	Anadarko USH1 Corporation
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☐
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	OO (please see Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0
		8	SHARED VOTING POWER
			14,364,949*
		9	SOLE DISPOSITIVE POWER
			0
		10	SHARED DISPOSITIVE POWER
			14,364,949*
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	14,364,949*
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	3.5%**
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	CO

* Represents 14,364,949 Common Units held of record by AUSH1.

** The calculation is based on a total of 408,390,278 Common Units issued and outstanding as of November 4, 2021.

Explanatory Note.

This Amendment No. 4 amends and supplements the Schedule 13D filed with the Securities and Exchange Commission on August 19, 2019 (the “Original Schedule 13D,” and as amended, the “Schedule 13D”) relating to the common units representing limited partner interests (the “Common Units”) in Western Midstream Partners, LP, a Delaware master limited partnership (the “Issuer”) beneficially owned by Occidental Petroleum Corporation (“Occidental”), OXY USA Inc. (“OXY USA”), Occidental Permian Manager LLC (“OPM”), OXY Oil Partners, Inc. (“OOP”), New OPL, LLC (“OPL”), Baseball Merger Sub 2, Inc. (“BMS”), Anadarko Petroleum Corporation (“Anadarko”), Western Gas Resources, Inc. (“WGRI”), APC Midstream Holdings, LLC (“AMH”), WGR Asset Holding Company LLC (“WGRAH”), Kerr-McGee Worldwide Corporation (“KWC”), Anadarko USH1 Corporation (“AUSH1”), Anadarko Holding Company (“AHC”) and Oxy USA WTP LP (“OXY USA WTP” and together with Occidental, OXY USA, OPM, OOP, OPL, BMS, Anadarko, WGRI, AMH, WGRAH, KWC, AUSH1 and AHC, the “Reporting Persons”). Capitalized terms used but not defined herein shall have the meanings ascribed to them in the Original Schedule 13D and subsequent amendments, as applicable.

The filing of this Amendment No. 4 shall not be construed as an admission that any of the Reporting Persons is for the purposes of Section 13(d) or 13(g) of the Securities Exchange Act of 1934, the beneficial owner of any of the Common Units reported herein. Pursuant to Rule 13d-4, each of the Reporting Persons disclaims all such beneficial ownership except to the extent of its pecuniary interest in any such Common Units, if applicable.

Item 2 of the Schedule 13D is hereby amended and supplemented by adding the following Reporting Persons and corresponding information:

(xiii) Oxy USA WTP LP, a Delaware limited partnership; and

(xiv) Anadarko Holding Company, a Utah corporation.

The general partner of Oxy USA WTP LP is OPM, and Oxy USA WTP LP is the manager of OPL. The business address of Oxy USA WTP LP is 5 Greenway Plaza, Suite 110, Houston, TX 77046 and its principal business is engaging in the exploration for and production of oil, gas and carbon dioxide.

Anadarko Holding Company is a wholly owned subsidiary of APC and is the majority shareholder of KWC. The business address of Anadarko Holding Company is 5 Greenway Plaza, Suite 110, Houston, TX 77046 and its principal business is to hold ownership interests in its various subsidiaries.

Item 2(d)-(e) is hereby amended and restated in its entirety.

During the past five years, none of the Reporting Persons have (i) been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors) nor (ii) been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and, as a result of such proceeding, was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Item 3 of the Schedule 13D is hereby amended and supplemented by adding the following:

The description of the transaction contemplated by the Unit Purchase Agreement (as defined below) in Item 4 of this Schedule 13D is hereby incorporated by reference into this Item 3.

Item 4 of the Schedule 13D is hereby amended and supplemented by adding the following:

Issuer Repurchase

On December 7, 2021, the Issuer entered into a Unit Purchase Agreement with WGRAH (the “Unit Purchase Agreement”), pursuant to which, on December 13, 2021, the Issuer repurchased 2,500,000 Common Units held by WGRAH for a purchase price of $20.09 per Common Unit, representing an aggregate purchase price of $50,225,000.

The foregoing description of the Unit Purchase Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Unit Purchase Agreement, which is incorporated by reference as Exhibit Y.

Item 5 of the Schedule 13D is hereby amended and restated in its entirety as follows:

(a) and (b) See the information on the cover pages of this Amendment No. 4 to the Schedule 13D, which is incorporated by reference herein.

(c) None of the Reporting Persons, or to the Reporting Persons’ knowledge, none of the Listed Persons, has effected any transactions in the Common Units during the past 60 days, other than as described in Item 4 of this Amendment No. 4 to the Schedule 13D.

(e) As of the date of this Amendment No. 4, OXY Oil Partners, Inc. does not beneficially own any Common Units of the Issuer.

Item 6 is hereby amended and supplemented by adding the following:

The description of the Unit Purchase Agreement in Item 4 above is hereby incorporated by reference into this Item 6. A copy of the Unit Purchase Agreement is included as an exhibit to this filing.

Item 7 of the Schedule 13D is hereby amended and supplemented by inserting the following exhibits:

SIGNATURES

After reasonable inquiry and to the best of their knowledge and belief, the undersigned certify that the information set forth in this statement is true, complete and correct.

Date: December 20, 2021