Clay Williams is the Chairman, President, and Chief Executive Officer of National Oilwell Varco (NOV). Previously, he served as NOV’s President and Chief Operating Officer and its Executive Vice President and Chief Financial Officer. Prior to its merger with National Oilwell, Clay served as Varco’s Chief Financial Officer. He also served as Vice President of Finance, Vice President of Corporate Development, and Vice President of Pipeline Services for Varco and Tuboscope before the merger between the two companies. Before Tuboscope, he worked for SCF Partners and Shell Oil Company. Clay has a Bachelor of Science in Civil and Geological Engineering from Princeton University and holds a Master’s of Business Administration from the University of Texas.
Greg L. Armstrong
Mr. Armstrong has been a Director of the Company since March 2005 and previously served as a Director of Varco from May 20, 2004, until its merger with the Company on March 11, 2005. Mr. Armstrong is a co-founder and former Chairman and CEO of Plains All American Pipeline, L.P., a publicly-traded master limited partnership engaged in the business of marketing, gathering, transporting, terminalling, and storing crude oil. Mr. Armstrong retired as CEO of Plains in October 2018 and as Chairman in December 2019 and continues to serve as a member of its board of directors. Mr. Armstrong currently serves as a director of Memorial Hermann Healthcare System and serves on the advisory boards of the Baker Institute at Rice University and Veriten. He is a member of the adjunct faculty for the University of Oklahoma’s Executive MBA in Energy program; the Advisory Board of the Cox School’s Maguire Energy Institute at Southern Methodist University; and the National Petroleum Council, where he served as Chairman from 2017 to 2019. He previously served as a director in the Federal Reserve System for eleven years, serving the last three years as Chair of The Dallas Fed, completing his term in 2021. Mr. Armstrong is a member of the Texas Business Hall of Fame and a Distinguished Alumnus of Southeastern Oklahoma State University.
Marcela E. Donadio
Ms. Donadio has been a Director of the Company since April 2014. Ms. Donadio has over 37 years of audit and public accounting experience with a specialization in domestic and international operations in all segments of the energy industry. She was Americas Oil & Gas Sector Leader of Ernst & Young LLP, from which she retired in March 2014. Ms. Donadio joined Ernst & Young in 1976, serving since 1989 as audit partner for multiple companies in the oil and gas industry. She held various energy industry leadership positions until being named Americas Oil & Gas Sector Leader in 2007. In that role she was responsible for one of the firm's most significant industry groups in the US and throughout the Americas. Ms. Donadio earned a Bachelor of Science degree in Accounting from Louisiana State University and is a licensed certified public accountant in the State of Texas.
Ben A. Guill
Mr. Guill has been a Director of the Company since 1999. Since 2010, Mr. Guill has been a founding Partner of White Deer Energy, a private equity fund focused on the exploration & production, oilfield service and equipment, and midstream sectors of the oil and gas industry. Until April 2007, he was President of First Reserve Corporation, a corporate manager of private investments focusing on the energy and energy-related sectors, which he joined in September 1998. Prior to joining First Reserve, Mr. Guill was the Managing Director and Co-head of Investment Banking of Simmons & Company International, an investment-banking firm specializing in the oil service industry.
David D. Harrison
Mr. Harrison has been a Director of the Company since August 2003. He has served as Executive Vice President and Chief Financial Officer of Pentair, Inc., a diversified manufacturer in water technologies and enclosures businesses since February 2000 until his retirement in February 2007. From September 1999 through February 2000, Mr. Harrison was Executive Vice President and Chief Financial Officer of the Scotts Company, a lawn and garden products company. He was Executive Vice President and Chief Financial Officer and a Director of Coltec Industries, a company in the industrial and aerospace arena from 1996 to 1999. He also served as Executive Vice President and Chief Financial Officer of Pentair, Inc. from 1994 to 1996.
Eric L. Mattson
Mr. Mattson has been a Director of the Company since March 2005. Mr. Mattson served as a Director of Varco (and its predecessor, Tuboscope Inc.) from January 1994 until its merger with the Company on March 11, 2005. Mr. Mattson served as the EVP-Finance of Select Energy Services, Inc., a public oil service company located in Houston until his retirement in March 2018. Mr. Mattson also served as Senior Vice President and Chief Financial Officer of VeriCenter, Inc., a private provider of managed hosting services, from 2003 until its acquisition in August 2007. From November 2002 until October 2003, Mr. Mattson worked as an independent consultant. Mr. Mattson was the Chief Financial Officer of Netrail, Inc., a private Internet backbone and broadband service provider, from September 1999 until November 2002. From July 1993 until May 1999, Mr. Mattson served as Senior Vice President and Chief Financial Officer of Baker Hughes Incorporated, a provider of products and services to the oil, gas and process industries.
Patricia B. Melcher
Ms. Melcher has been a Director of the Company since January 2024. Ms. Melcher is a Managing Partner of EIV Capital, an energy-focused private equity firm she co-founded in 2009. Prior to co-founding EIV Capital, Ms. Melcher founded Allegro Capital Management in 1997, an investment firm which made equity investments in energy companies and provided consulting services. During her tenure at Allegro, she served as interim chief executive officer for Petrocom Energy Group from 2003 to 2004. Ms. Melcher joined SCF Partners at its formation to focus on private equity investments in the oilfield services sector and held positions of increasing responsibility from 1989 to 1994. Ms. Melcher has over 35 years of energy business experience, beginning her career as an investment banker for Simmons & Company International in 1986. Ms. Melcher received a Bachelor of Science in Systems Engineering from the University of Virginia and a Master of Business Administration from Harvard University.
William R. Thomas
Mr. Thomas has been a Director of the Company since November 2015. Mr. Thomas had served as the Non-Executive Chairman of EOG Resources, Inc. from October 2021 until October 2022 (NYSE: EOG). From January 2014 to October 2021, Mr. Thomas served as the Chairman and CEO of EOG. Prior to that, he served as President and Chief Executive Officer from July 2013 through December 2013 and as President from September 2011 to July 2013. Mr. Thomas previously held other leadership positions at EOG, including Senior Executive Vice President, Exploitation and Senior Executive Vice President, Exploration. Mr. Thomas received a Bachelor of Science degree in Geology from Texas A&M University in 1975.
Robert S. Welborn
Mr. Welborn has been a Director of the Company since October 2021. Since December 2021, Mr. Welborn has been serving as the Head of Meta Decision Science for Meta Inc. Prior to that, he was the Head of Programs Data Science, Small Business Group for Meta Inc. where he oversaw the development of solutions used by over 140 million businesses around the world. Before joining Meta Inc. in 2020, he held various positions within General Motors between 2018 and 2020, including Global Chief Data and Analytics Officer and served in several positions of increasing responsibility at USAA between 2009 and 2017, including Chief Data Scientist. From 1996 to 2009, Mr. Welborn was employed at Perot Systems and Wagonhound Investments. Mr. Welborn holds a Bachelor of Science in Engineering from Texas A&M University and a Master of Business Administration from the University of California, San Diego.