Pioneer Management

Wm. Stacy Locke, President and Chief Executive Officer
Mr. Locke has served as one of our directors as well as president of the Company since May 1995, when he joined Pioneer. In December 2003, Mr. Locke was appointed chief executive officer. In addition to his continuous role as president, Mr. Locke has also served as our chief financial officer and chief operating officer. Prior to joining Pioneer, Mr. Locke was in investment banking with Arneson, Kercheville, Ehrenberg & Associates from 1993 to 1995 and Chemical Banking Corp. from 1988 to 1992. He worked for Tesoro Petroleum Corp., Valero Energy Corp. and Huffco Petroleum Corp. as a geologist from 1979 to 1986. Mr. Locke received a Bachelor’s Degree in geology from the University of California Santa Barbara and a Master's of Business Administration Degree from Southern Methodist University. 
Lorne E. Phillips, Executive Vice President and Chief Financial Officer
Mr. Phillips was appointed executive vice president and chief financial officer in February 2009. Prior to joining Pioneer, Mr. Phillips worked for 10 years at Cameron International Corp., serving most recently as vice president and treasurer. Prior to that, he was general manager of Cameron's Canadian valves operations, vice president of marketing and M&A for the valves division, and business development manager for Cameron. Before joining Cameron, he was a financial analyst for SCF Partners, a provider of equity capital to energy service and equipment companies, and for Simmons & Company International, an investment bank focused on the energy industry.
Brian L. Tucker, Executive Vice President and President of Drilling Services Segment
Mr. Tucker was appointed president of our Drilling Services segment effective January 1, 2015. Since joining Pioneer in 2012, Mr. Tucker has served as senior vice president over Appalachia, Utah and North Dakota drilling divisions. Prior to joining Pioneer, Mr. Tucker was a vice president for Helmerich and Payne (H&P), managing its South Texas operations from 2010 to 2012. From 2004 to 2010, he served as drilling engineer and operations manager for the Barnett Shale, South Texas and West Texas operations for H&P. Mr. Tucker served eight years as an officer in the U.S. Army, is a West Point graduate with a Bachelor of Science in Systems Engineering, and completed the Harvard Business School Advanced Management Program in 2014.
Carlos R. Peña, Executive Vice President, President of Production Services Segment, General Counsel, Secretary and Compliance Officer
Mr. Peña joined Pioneer in 2008 as our Senior Vice President, General Counsel, Secretary and Compliance Officer.  As a Compliance Officer, Mr. Peña also oversaw the compliance function and Health, Safety and the Environment (HSE) Department at Pioneer.  In 2015 Mr. Peña was promoted to Executive Vice President and in 2016 he was promoted to President of our Production Services Segment, having gained valuable experience with a variety of industry issues during his almost ten year tenure here. Mr. Peña has practiced law since 1992 and has extensive experience providing both outside corporate and securities counsel with Fulbright & Jaworski L.L.P., Cox Smith Matthews Incorporated, and Vinson & Elkins L.L.P., and in-house M&A counsel with AT&T, Inc. Mr. Peña received a Bachelor's Degree in Economics from Princeton University and a Juris Doctor law degree from the University of Texas School of Law, and completed the Harvard Business School Advanced Management Program in 2016.
John “Skip” Locken, Vice President Operations, Drilling Services 
Mr. Locken joined Pioneer in 2009 as a North Dakota Division manager after serving as a drilling superintendent with Nabors Drilling USA. In 2014, he was promoted to vice president for the North Region. Mr. Locken has more than 30 years of experience in the drilling industry.
Donald G. Lacombe, Senior Vice President, Marketing Drilling Services
Mr. Lacombe has served as an officer of Pioneer since August 2000. Prior to joining Pioneer, Mr. Lacombe was the contracts and sales manager for Grey Wolf Drilling's South Texas Division and for Flournoy Drilling Co. from April 1993 to August 2000.
Joe Freeman, Senior Vice President, Well Servicing
Mr. Freeman joined Pioneer in 2008 as vice president of Well Servicing and was promoted to senior vice president in 2014. Previously, Mr. Freeman served as vice president of the well servicing division of WEDGE Oil and Gas Services from 2005 to 2008, Gulf Coast Division manager of Key Energy Services from 1998 to 2004, and independent entrepreneur and owner of JPF Well Service from 1987 to 1998, which was sold to Key Energy Services in 1998.
Scott Keenen, Vice President, Global Human Resources
Mr. Keenen joined Pioneer in 2010. He has 28 years of domestic and international experience across a diverse group of industries, including energy, technology, telecommunications and professional services.  Prior to joining Pioneer, Mr. Keenen was vice president, Global Human Resources, for Premier Research Group, a global contract research organization. Mr. Keenen started his career with Schlumberger Ltd., where he worked for 23 years. Beginning as a cased-hole field engineer working in the Gulf of Mexico, he spent the majority of his Schlumberger career in Human Resources management assignments.  
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