Patterson-UTI Energy Inc. said April 8 that Mark S. Siegel has advised the company of his intention to retire as executive chairman after more than 25 years of continuous service to Patterson-UTI Energy and its predecessor companies.

Siegel has decided not to stand for re-election to the board of directors and to retire as executive chairman, at the time of the company’s annual shareholder meeting, when it is anticipated that Curtis Huff will be appointed non-executive chairman. Huff has been a member of the board of directors of Patterson-UTI and one of its predecessor companies for 23 years and currently serves as the company’s lead independent director.

“Mark's many contributions to Patterson-UTI and the U.S. land drilling industry as a whole have been incomparable and immeasurable. When he first became involved with UTI Energy in 1995, that company’s total enterprise value was only $16 million. Among other notable M&A transactions, Mark was instrumental in achieving the merger of Patterson Energy and UTI Energy in 2001.

“Under his visionary leadership, a small, regional drilling company, through both mergers and organic growth, has become a leading oilfield services company and a primary player in the U.S. unconventional shale revolution. Given Mark’s long history with Patterson-UTI and his deep experience in our industry, I am pleased that Mark has agreed to provide transition support services and advice on strategic and other matters to the company after he steps down as executive chairman,” Andy Hendricks, Patterson-UTI Energy’s president and CEO, said.