EX-21.1 2 d639374dex211.htm EX-21.1 EX-21.1

Exhibit 21.1

Subsidiaries of the Registrant

 

Name

    State of
Incorporation or
organization

Ambar Lone Star Fluid Services LLC

    Texas

Patterson Petroleum LLC

    Texas

Patterson-UTI Drilling Canada Limited

    Nova Scotia

Patterson-UTI Drilling Company LLC

    Texas

Patterson-UTI Drilling International, Inc.

    Delaware

Patterson-UTI International Holdings GP 1 LLC

    Delaware

Patterson-UTI International Holdings, Inc.

    Delaware

Patterson-UTI Management Services, LLC

    Delaware

Universal Pressure Pumping, Inc.

    Delaware

Universal Well Services, Inc.

    Delaware