Form SCHEDULE 13G/A PATTERSON UTI ENERGY Filed by: BEP Diamond Topco L.P.

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: (i) BEP Diamond Topco L.P. (ii) BEP Diamond Topco LLC (iii) BEP Diamond Aggregator L.P. (iv) BCP VII/BEP II Holdings Manager L.L.C. (v) Blackstone Energy Management Associates II L.L.C. (vi) Blackstone Management Associates VII L.L.C. (vii) BMA VII L.L.C. (viii) Blackstone EMA II L.L.C. (ix) Blackstone Holdings III L.P. (x) Blackstone Holdings III GP L.P. (xi) Blackstone Holdings III GP Management L.L.C. (xii) Blackstone Inc. (xiii) Blackstone Group Management L.L.C. (xiv) Stephen A. Schwarzman BEP Diamond Topco LLC is the general partner of BEP Diamond Topco L.P. BEP Diamond Aggregator L.P. holds a majority of the limited liability company interests in BEP Diamond Topco LLC, and has the power to appoint the majority of the members of the board of managers of BEP Diamond Topco LLC. BCP VII/BEP II Holdings Manager L.L.C. is the general partner of BEP Diamond Aggregator L.P. Blackstone Energy Management Associates II L.L.C. and Blackstone Management Associates VII L.L.C. are the managing members of BCP VII/BEP II Holdings Manager L.L.C. BMA VII L.L.C. is the sole member of Blackstone Management Associates VII L.L.C. Blackstone EMA II L.L.C. is the sole member of Blackstone Energy Management Associates II L.L.C. Blackstone Holdings III L.P. is the managing member of each of BMA VII L.L.C. and Blackstone EMA II L.L.C. Blackstone Holdings III GP L.P. is the general partner of Blackstone Holdings III L.P. Blackstone Holdings III GP Management L.L.C. is the general partner of Blackstone Holdings III GP L.P. Blackstone Inc. is the sole member of Blackstone Holdings III GP Management L.L.C. The sole holder of the Series II preferred stock of Blackstone Inc. is Blackstone Group Management L.L.C. Blackstone Group Management L.L.C. is wholly-owned by Blackstone Inc.'s senior managing directors and controlled by its founder, Stephen A. Schwarzman. Each Reporting Person may be deemed to beneficially own the Common Stock, $0.01 par value ("Common Stock") of Patterson-UTI Energy, Inc. (the "Issuer") beneficially owned by entities directly or indirectly controlled by it or him, but neither the filing of this Schedule 13G nor any of its contents shall be deemed to constitute an admission that any Reporting Person (other than BEP Diamond Topco L.P. and BEP Diamond Aggregator L.P. to the extent it directly holds Issuer securities reported herein) is the beneficial owner of the Common Stock referred to herein for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, or for any other purpose and each of the Reporting Persons expressly disclaims beneficial ownership of such shares of Common Stock. The filing of this statement should not be construed to be an admission that any member of the Reporting Persons are members of a "group" for the purposes of Sections 13(d) and 13(g) of the Act.

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, other than activities solely in connection with a nomination under ?? 240.14a-11.

EXHIBIT LIST Exhibit 99.1 Signature Blocks.