UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

WESTERN GAS PARTNERS, LP

(Name of Issuer)

Common Units

(Title of Class of Securities)

958254104

(CUSIP Number)

February 23, 2017

(Date of Event which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

☐ Rule 13d-1(b)

☒ Rule 13d-1(c)

☐ Rule 13d-1(d)

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Western Gas Partners, LP (the “Company”)

1201 Lake Robbins Drive

The Woodlands, Texas 77380

Each of the following is hereinafter individually referred to as a “Reporting Person” and collectively as the “Reporting Persons.” This statement is filed on behalf of:

FR XIII WES Holdings Parent LLC is the managing member of FR XIII WES Holdings, LLC. FR XIII Charlie AIV, L.P. is the sole member of FR XIII WES Holdings Parent LLC. First Reserve GP XIII, L.P. is the general partner of FR XIII Charlie AIV, L.P. First Reserve GP XIII Limited is the general partner of each of First Reserve GP XIII, L.P. and FR WES Co-Investment LP. William E. Macaulay is Chairman of First Reserve GP XIII Limited and has the right to appoint a majority of the board of directors of First Reserve GP XIII Limited.

One Lafayette Place, Third Floor, Greenwich, Connecticut 06830

Each of FR XIII WES Holdings LLC, FR WES Co-Investment LP and FR XIII WES Holdings Parent LLC is organized under the laws of the State of Delaware. Mr. Macaulay is a U.S. citizen. Each of FR XIII Charlie AIV, L.P., First Reserve GP XIII, L.P. and First Reserve GP XIII Limited are organized under the laws of the Cayman Islands.

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Common Units (the “Common Units”).

958254104

Not applicable.

(a) Amount beneficially owned:

As of the date hereof, each of the Reporting Persons may be deemed to be the beneficial owner of the Common Units listed on such Reporting Person’s cover page. FR XIII WES Holdings LLC directly holds 4,512,117 Common Units and 4,512,118 Series A Preferred Units of the Company (“Preferred Units”) that will convert into Common Units on a one-for-one basis on May 2, 2017, pursuant to the terms of a Consent and Conversion Agreement, dated as of February 22, 2017, entered into by and among the Company and holders of Preferred Units party thereto (the “Conversion Agreement”), and FR WES Co-Investment LP directly holds 2,343,750 Common Units and 2,343,750 Preferred Units that will convert into Common Units on a one-for-one basis on May 2, 2017, pursuant to the terms of the Conversion Agreement. Mr. Macaulay may be deemed to beneficially own an additional 621,770 Common Units held directly by KA First Reserve, LLC. Mr. Macaulay is Chairman of First Reserve GP XI, Inc. and has the right to appoint a majority of the board of directors. First Reserve GP XI, Inc. is the general partner of First Reserve GP XI, L.P., which owns a majority of the membership interests in KA First Reserve, LLC and controls the board of managers of KA First Reserve, LLC.

(b) Percent of class:

As of the date hereof, each of the Reporting Persons may be deemed to be the beneficial owner of the percentage of shares of Common Stock listed on such Reporting Person’s cover page.

(c) Number of Shares as to which the Reporting Person has:

See each cover page hereof.

See each cover page hereof.

See each cover page hereof.

See each cover page hereof.

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If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following:  ☐

Not applicable.

Not applicable.

Not applicable.

Not Applicable.

Each of the Reporting Persons hereby makes the following certification:

By signing below the undersigned certifies that, to the best of its or his knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under §240.14a-11.

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SIGNATURE

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

Dated: April 13, 2017

[Western Gas Partners, LP – Schedule 13G]

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[Western Gas Partners, LP – Schedule 13G]

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EXHIBIT LIST

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Exhibit A

JOINT FILING AGREEMENT

Pursuant to and in accordance with the Securities Exchange Act of 1934, as amended, and the rules and regulations thereunder (the “Exchange Act”) the undersigned hereby agree to the joint filing of FR XIII WES Holdings LLC, FR WES Co-Investment LP, FR XIII WES Holdings Parent LLC, FR XIII Charlie AIV, L.P., First Reserve GP XIII, L.P., First Reserve GP XIII Limited, and William E. Macaulay, on behalf of each of them of any filing required by such party under Section 13 or Section 16 of the Exchange Act or any rule or regulation thereunder (including any amendment, restatement, supplement, and/or exhibit thereto) with respect to securities of Western Gas Partners, LP, a Delaware limited partnership, and further agree to the filing, furnishing, and/or incorporation by reference of this Agreement as an exhibit thereto. This Agreement shall remain in full force and effect until revoked by any party hereto in a signed writing provided to each other party hereto, and then only with respect to such revoking party. This Agreement may be executed in any number of counterparts all of which taken together shall constitute one and the same instrument.

IN WITNESS WHEREOF, the undersigned hereby execute this Agreement this 13^th day of April 2017.

[Western Gas Partners, LP – Joint Filing Agreement]

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[Western Gas Partners, LP – Joint Filing Agreement]

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Exhibit B

POWER OF ATTORNEY

(LIMITED)

KNOW ALL MEN BY THESE PRESENTS, that I, WILLIAM E. MACAULAY of the Town/City of GREENWICH, County of FAIRFIELD, State of CONNECTICUT, reposing special trust and confidence in ANNE E. GOLD, of the Town of RYE, County of WESTCHESTER, State of NEW YORK and/or, ROBERT J. GALLAGHER, of the Town of RYE, County of WESTCHESTER, State of NEW YORK, have made, constituted and appointed, and by these presents do make, constitute and appoint each of the said ANNE E. GOLD and/or ROBERT J. GALLAGHER, my true and lawful attorney-in-fact and agent, both FOR ME PERSONALLY and in my name, place and stead, IN MY CAPACITY AS AN OFFICER OR DIRECTOR OF:

FRC FOUNDERS CORPORATION (“FOUNDERS”)

FIRST RESERVE CORPORATION, L.L.C. (“FRC”)

FIRST RESERVE PARTNERS LIMITED (“FRPL”)

FIRST RESERVE MANAGEMENT LIMITED (“FRML”)

FIRST RESERVE GP XIII LIMITED (“GP XIII”)

FIRST RESERVE GP XII LIMITED (“GP XII”)

FIRST RESERVE GP XI, INC. (“GP XI”)

FR XI OFFSHORE GP LIMITED (“OFFSHORE XI”)

FR HORIZON GP LIMITED (“FR HORIZON”)

FIRST RESERVE GP X, INC. (“GP X”)

FR X OFFSHORE GP LIMITED (“OFFSHORE X”)

FIRST RESERVE ENERGY INFRASTRUCTURE GP LIMITED (“FREI”)

FIRST RESERVE ENERGY INFRASTRUCTURE GP II LIMITED (“FREI II”)

FIRST RESERVE OLD CLEM GP LIMITED (“CLEM”)

FIRST RESERVE OLD CLEM GP II LIMITED (“CLEM II”)

FR DGE III ALTERNATIVE B GP, LTD. (“DGE III”)

FIRST RESERVE UPSTREAM ANNEX GP, INC. (“ANNEX”)

or any entity of which any the foregoing is the direct or indirect general partner or for which any of the foregoing otherwise has the authority to act (collectively with FOUNDERS, FRC, FRPL, FRML, GP XIII, GP XII, GP XI, OFFSHORE XI, FR HORIZON, GP X, OFFSHORE X, FREI, FREI II, CLEM, CLEM II, DGE III, and ANNEX the “First Reserve Entities”), with full power and authority to do and perform each and every act necessary, as fully as I might do if personally present, to accomplish and complete the following acts or transactions:

1. With respect to any entity in which any First Reserve Entities have an investment (each a “Company”), sign on my behalf, any and all filings (including filings with the Securities and Exchange Commission), agreements, notices or documents arising from, or related to any Company, including, (a) any holdings or investments of any First Reserve Entities in any Company; and (b) any holdings or investments of mine in any Company.

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2. Seek or obtain, as my representative and on my behalf, from any third party, including brokers, employee benefit plan administrators and trustees, information on transactions involving any Company or the securities of any Company, and I hereby authorize any such persons to release any such information to either attorney-in-fact designated hereunder and approve and ratify any such release of information; and

3. Perform any and all other acts which in the discretion of either such attorney-in-fact are necessary or desirable for and on my behalf in connection with the foregoing.

I acknowledge that:

(a) this Power of Attorney authorizes, but does not require, either such attorney-in-fact to act in his or her discretion on information provided to either such attorney-in-fact without independent verification of such information;

(b) any documents prepared and/or executed by either such attorney-in-fact on my behalf pursuant to this Power of Attorney will be in such form and will contain such information and disclosure as either such attorneys-in-fact, in his or her discretion, deems necessary or desirable;

(c) neither such attorney-in-fact nor any Company assumes (i) any liability for my responsibility to comply with the requirements of any law or regulation, including without limitation the Securities Act of 1933, as amended (the “Securities Act”) or the Exchange Act of 1934, as amended (the “Exchange Act”), or (ii) any liability of mine for any failure to comply with such requirements; and

(d) this Power of Attorney does not relieve me from responsibility for compliance with my obligations under any law or regulation, including without limitation the requirements under the Securities Act and the Exchange Act.

I hereby give and grant ANNE E. GOLD and/or ROBERT J. GALLAGHER, in the capacity set forth above, full power and authority to do and perform all and every act and thing whatsoever requisite, necessary or appropriate to be done in and about the foregoing matters as fully to all intents and purposes as I might or could do if present, hereby ratifying all that either such attorney-in-fact of, for and on my behalf, shall lawfully do or cause to be done by virtue of this Power of Attorney.

[Remainder of Page Intentionally Blank]

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This POWER OF ATTORNEY shall remain in effect until revoked and shall not be affected by disability of the Principal.

EXECUTED this 8th Day of December, 2016

/s/ William E. Macaulay                    

STATE OF CONNECTICUT)

                                                  )SS. Greenwich

COUNTY OF FAIRFIELD)

The foregoing instrument was acknowledged before me this 8th day of December, 2016, by William E. Macaulay, the Principal.

Witness my hand and official seal: Wendy Chauncey, Notary /s/ Wendy Chauncey

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