Tarrant County Sheriff's Office spokesman Terry Grisham says the 25-year-old man was working at an elevated position when a piece of equipment hit him in the head.
Grisham says the man did not fall to the ground because he was wearing a safety harness.
The Texas Railroad Commission and Occupational Safety and Health Administration are investigating.
The commission says XTO Energy is the well operator at the site, and the man worked for a contractor, Express Energy.
