EX-21.1 2 d78488exv21w1.htm EX-21.1
Exhibit 21.1
Subsidiaries of the Registrant

|  | State of
|  | Incorporation or
Name |  | 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 Management Services, LLC |  | Delaware
Universal Pressure Pumping, Inc. |  | Delaware
Universal Well Services, Inc. |  | Delaware