Sept 21 (Reuters) - Onshore drilling contractor Patterson-UTI Energy Inc said its Chief Executive Douglas Wall will retire at the end of this month.
He will be replaced by Chief Operating Officer William Hendricks.
Wall has been the CEO since October 2007.
Hendricks, who joined Patterson in April 2012, worked at industry leader Schlumberger Ltd for 24 years.
The company's shares closed at $17.46 on Friday on the Nasdaq.