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 Chief Operating Officer
Mr. Tucker was appointed Chief Operating Officer effective January 1, 2019.  Since joining Pioneer in 2012, Mr. Tucker has served as our Senior Vice President Drilling, then as President of our Drilling Services Business 2015-2018, and as President of Drilling and Well Servicing  April -December 2018. Prior to joining Pioneer, Mr. Tucker was a Vice President for Helmerich and Payne (H&P) managing the South Texas operations from 2010 to 2012. From 2004 to 2010, Mr. Tucker 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. He currently serves as a board member of Catholic Charities Archdiocese of San Antonio.
Carlos R. Peña, Executive Vice President and Chief Strategic Officer
Mr. Peña was appointed Chief Strategic Officer effective January 1, 2019.  Mr. Peña joined Pioneer in 2008 as a Senior Vice President, General Counsel, Secretary and Compliance Officer. In 2016, Mr. Peña was promoted to President of our Production Services Business and in April 2018 he assumed the role of President of Wireline and Coiled Tubing Services. Prior to joining Pioneer, Mr. Peña had been practicing law since 1992, with Fulbright & Jaworski L.L.P., Cox Smith Matthews Incorporated, Vinson & Elkins L.L.P., and AT&T, Inc. Mr. Peña received a Bachelor's Degree in Economics from Princeton University, a Juris Doctor degree from the University of Texas School of Law, and completed the Harvard Business School Advanced Management Program in 2016.
Bryce Seki, Vice President, General Counsel, Secretary and Compliance Officer
Mr. Seki joined the Company in May of 2011, first serving as Corporate Counsel and then Associate General Counsel before being promoted to Vice President - Associate General Counsel in May 2016. Prior to joining the Company, Mr. Seki was an associate attorney at Fulbright & Jaworski L.L.P. (now known as Norton Rose Fulbright). Mr. Seki received a Bachelor of Arts from the University of Notre Dame and a Doctor of Jurisprudence from Notre Dame Law School. 
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.
W. Scott Keenen, Senior 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.