13G Filing: Luminus Management and Select Energy Services Inc (WTTR)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No.     )*

Select Energy
Services, Inc.

(Name of Issuer)

Class A Common Stock, Par Value $0.01

(Title of Class of Securities)

81617J301

(CUSIP Number)

James J. Moloney

Gibson, Dunn & Crutcher LLP

3161 Michelson Drive

Irvine, CA 92612

(949)
451-4343

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

April 20, 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 in 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).

(a) Name of Issuer

Select Energy Services, Inc.

(b) Address of Issuers Principal Executive Offices

1820 North I-35, P.O. Box 1715, Gainesville, Texas 76241

(a) Name of Person(s) Filing:

(A) LUMINUS MANAGEMENT, LLC

Luminus Management, LLC is the investment adviser of Luminus Energy Partners Master Fund, Ltd.

(B) LUMINUS ENERGY PARTNERS MASTER FUND, LTD.

(b) Address of Principal Business Office or, if none, Residence:

(A) 1700 Broadway, 38th Floor, New York, NY 10019

(B) 1700 Broadway, 38th Floor, New York, NY 10019

(c) Citizenship:

(A) DELAWARE

(B) BERMUDA

(d)
Title of Class of Securities:

Class A Common Stock, Par Value $0.01

(e) CUSIP Number:

81617J301

Not applicable.

Provide the following information regarding the aggregate number and percentage of the class
of securities of the issuer identified in Item 1.

(a), (b), and (c)

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.

By signing below I certify that, to the best of my 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.

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: May 1, 2017

Exhibit A Schedule 13G Joint Filing Agreement

The undersigned and each other person executing this joint filing agreement (this Agreement) agree as follows:

(i) The undersigned and each other person executing this Agreement are individually eligible to use the Schedule 13G to which this Exhibit is attached and
such Schedule 13G is filed on behalf of the undersigned and each other person executing this Agreement; and

(ii) The undersigned and each other person
executing this Agreement are responsible for the timely filing of such Schedule 13G and any amendments thereto, and for the completeness and accuracy of the information concerning such person contained therein; but none of the undersigned or any
other person executing this Agreement is responsible for the completeness or accuracy of the information statement concerning any other persons making the filing, unless such person knows or has reason to believe that such information is inaccurate.

This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, but all of which, taken together, shall
constitute one and the same instrument.

Dated: May 1, 2017

Exhibit B Power of Attorney

Know all by these presents, that each of the undersigned hereby constitutes and appoints Jonathan Barrett as the undersigneds true and lawful attorneys-in-fact to:

(1) execute for and on behalf of the undersigned, in the
undersigneds capacity as an officer, director or beneficial owner of Common Shares of Select Energy Services, Inc. (the Issuer), the Statement on Schedule 13G (or Schedule 13D, if applicable) in accordance with Section 13(d) of the
Securities Exchange Act of 1934, as amended (the Act), and the rules thereunder;

(2) do and perform any and all acts for and on behalf of the
undersigned which may be necessary or desirable to complete and execute any such Statement on Schedule 13G (or Schedule 13D, if applicable) and all amendment(s) thereto and timely file such form with the United States Securities and Exchange
Commission and any stock exchange or similar authority;

(3) execute for and on behalf of the undersigned, in the undersigneds capacity as an
officer, director or beneficial owner of Common Shares of the Issuer, to sign any reports on Form 3 (Initial Statement of Beneficial Ownership of Securities), Form 4 (Statement of Changes in Beneficial Ownership of Securities) and Form 5 (Annual
Statement of Beneficial Ownership of Securities) relating to transactions by the undersigned in Common Shares or other securities and all amendments thereto in accordance with Section 16 of the Act, and the rules thereunder; and

(4) take any other action of any type whatsoever in connection with the foregoing which, in the opinion of such attorneys-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorneys-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorneys-in-fact may approve in such attorneys-in-facts discretion.

The undersigned hereby grant to such attorneys-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite, necessary, or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the undersigned might or could do
if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that such attorneys-in-fact, or such attorneys-in-facts substitute or substitutes, shall lawfully do or cause to be done by virtue of this Power of Attorney and the rights and powers herein granted. The
undersigned acknowledges that the foregoing attorneys-in-fact, in serving in such capacity at the request of the undersigned, are not assuming, nor is the Issuer
assuming, any of the undersigneds responsibilities to comply with Sections 13(d) or 16 of the Act and the rules thereunder.

This Power of Attorney
shall remain in full force and effect until the undersigned is no longer required to (i) file a Statement on Schedule 13G or Schedule 13D with respect to the undersigneds holdings of and transactions in securities issued by the Issuer or
(ii) report transactions and holdings on Forms 3, 4 and 5, unless earlier revoked by the undersigned in a signed writing delivered to the foregoing
attorneys-in-fact.

[Signatures to
Follow]

IN WITNESS WHEREOF, each of the undersigned has caused this Power of Attorney to be executed as of this 1st day
of May, 2017.