X0206 3 2019-05-22 1 0001748773 RATTLER MIDSTREAM LP RTLR 0001539838 Diamondback Energy, Inc. 500 WEST TEXAS AVENUE, SUITE 1200 MIDLAND TX 79701 1 0 0 0 0001771397 Energen Resources Corp 500 WEST TEXAS AVENUE, SUITE 1200 MIDLAND TX 79701 1 0 0 0 This Form 3 is being filed jointly by Diamondback Energy, Inc. and Energen Resources Corporation (together, the "Reporting Persons") in connection with the effectiveness of the Registration Statement on Form S-1, as amended (File No. 333-226645), filed by Rattler Midstream LP (the "Issuer"). Diamondback Energy, Inc. is the sole shareholder of Energen Resources Corporation, which is the sole member of Rattler Midstream LLC (the "General Partner"), which owns the non-economic general partner interest in the Issuer. On the basis of the relationship between the Reporting Persons (whether directly or through their affiliates) and certain directors of the General Partner, the general partner of the Issuer, the Reporting Persons may be deemed to be directors of the Issuer. /s/ Teresa L. Dick, as Executive Vice President, Chief Accounting Officer and Assistant Secretary of Diamondback Energy, Inc. 2019-05-22 /s/ Teresa L. Dick, as Executive Vice President, Chief Accounting Officer and Assistant Secretary of Energen Resources Corporation 2019-05-22