Exhibit 4.5

THIRD SUPPLEMENTAL INDENTURE

THIRD Supplemental Indenture (this “Supplemental Indenture”), dated as of January 28, 2019, among Energen Corporation, an Alabama corporation, Energen Resources Corporation, an Alabama corporation, and EGN Services, Inc., an Alabama corporation (the “Guaranteeing Subsidiaries”), each a direct or indirect subsidiary of Diamondback Energy, Inc., a Delaware corporation (the “Company”), the Company, the other Guarantors (as defined in the Indenture referred to herein) and Wells Fargo Bank, National Association, as trustee under the Indenture referred to below (the “Trustee”).

W I T N E S S E T H

WHEREAS, the Company has heretofore executed and delivered to the Trustee an indenture (as amended and supplemented to the date hereof, the “Indenture”), dated as of October 28, 2016 providing for the issuance of 4.750% Senior Notes due 2024 (the “Notes”);

WHEREAS, the Indenture provides that under certain circumstances the Guaranteeing Subsidiaries shall execute and deliver to the Trustee a supplemental indenture pursuant to which the Guaranteeing Subsidiaries shall unconditionally guarantee all of the Company’s Obligations under the Notes and the Indenture on the terms and conditions set forth herein (the “Note Guarantee”); and

WHEREAS, pursuant to Section 9.01 of the Indenture, the Trustee is authorized to execute and deliver this Supplemental Indenture.

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Guaranteeing Subsidiaries, the Trustee and the other parties hereto mutually covenant and agree for the equal and ratable benefit of the Holders of the Notes as follows:

1.CAPITALIZED TERMS. Capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture.

2.AGREEMENT TO GUARANTEE. Subject to Article 10 of the Indenture, the Guaranteeing Subsidiaries, jointly and severally with the other Guarantors, unconditionally guarantee to each Holder of a Note authenticated and delivered by the Trustee and to the Trustee and its successors and assigns, that: (1) the principal of, premium on, if any, and interest and Special Interest, if any, on, the Notes will be promptly paid in full when due, whether at maturity, by acceleration, redemption or otherwise, and interest on the overdue principal of, premium on, if any, and interest and Special Interest, if any, on, the Notes, if lawful, and all other obligations of the Company to the Holders or the Trustee under the Indenture or the Notes will be promptly paid in full or performed, all in accordance with the terms of the Indenture and the Notes; and (2) in case of any extension of time of payment or renewal of any Notes or any of such other obligations, that the same will be promptly paid in full when due or performed in accordance with the terms of the extension or renewal, whether at stated maturity, by acceleration or otherwise.

3.NO RECOURSE AGAINST OTHERS. No director, officer, employee, incorporator or stockholder of the Company or any Guarantor, as such, will have any liability for any obligations of the Company or the Guarantors under the Notes, the Indenture, the Note Guarantees or for any claim based on, in respect of, or by reason of, such obligations or their creation. Each Holder of Notes by accepting a Note waives and releases all such liability. The waiver and release are part of the consideration for issuance of the Notes.

4.NEW YORK LAW TO GOVERN. THE INTERNAL LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

5.COUNTERPARTS. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of them together represent the same agreement. The exchange of copies of this Supplemental Indenture and of signature pages by facsimile or Portable Document Format (“PDF”) transmission shall constitute effective execution and delivery of this instrument as to the parties hereto and may be used in lieu of the original instrument for all purposes. Signatures of the parties hereto transmitted by facsimile or PDF shall be deemed to be their original signatures for all purposes.

6.EFFECT OF HEADINGS. The Section headings herein are for convenience only and shall not affect the construction hereof.

7.THE TRUSTEE. The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made solely by the Guaranteeing Subsidiaries and the Company.

[Signatures to Follow]

IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed and attested, all as of the date first above written.

GUARANTEEING SUBSIDIARIES:
ENERGEN CORPORATION
By:	/s/ Teresa L. Dick
Name:	Teresa L. Dick
Title:	Executive Vice President, Treasurer and
	Assistant Secretary
ENERGEN RESOURCES CORPORATION
By:	/s/ Teresa L. Dick
Name:	Teresa L. Dick
Title:	Chief Financial Officer, Executive Vice
	President, Treasurer and Assistant Secretary
EGN SERVICES, INC.
By:	/s/ Teresa L. Dick
Name:	Teresa L. Dick
Title:	Chief Financial Officer, Executive Vice
	President, Treasurer and Assistant Secretary
ISSUER:
DIAMONDBACK ENERGY, INC.
By:	/s/ Teresa L. Dick
Name:	Teresa L. Dick
Title:	Chief Financial Officer, Executive Vice
	President and Assistant Secretary

OTHER GUARANTORS:
DIAMONDBACK O&G LLC
By:	/s/ Teresa L. Dick
Name:	Teresa L. Dick
Title:	Executive Vice President, Chief Financial
	Officer and Assistant Secretary
DIAMONDBACK E&P LLC
By:	/s/ Teresa L. Dick
Name:	Teresa L. Dick
Title:	Executive Vice President, Chief Financial
	Officer and Assistant Secretary

TRUSTEE:
WELLS FARGO BANK, NATIONAL
ASSOCIATION, as Trustee
By:	/s/ Tina D. Gonzalez
	Authorized Signatory