EMPOWERED - INSPIRED - EXPERIENCED
The Right Leadership for Today’s E&P Market
OUR TEAM
Jeff Fisher has been Chief Executive Officer since December 2014 and has served as Ascent’s Chairman of the Board since February 2015. Before joining Ascent, he served as COO for American Energy Partners and was instrumental in building multiple basin-focused companies including Ascent. Mr. Fisher worked at Chesapeake Energy Corporation from 2003 to 2013, most recently serving as Executive Vice President of Production, where he was responsible for upstream operations and integrated field developments. Prior to Chesapeake, he worked in various engineering and operational leadership roles at BP PLC, Vastar Resources and ARCO Oil and Gas, Inc. Mr. Fisher earned a Bachelor of Science in Mechanical Engineering from Oklahoma State University.

Mrs. Grigsby joined Ascent in 2015 as Executive Vice President – Chief Financial Officer. She previously worked at Chesapeake Energy Corporation for 19 years in management roles including her most recent positions as Senior Vice President, Corporate and Strategic Planning and Senior Vice President, Treasurer and Corporate Secretary. Prior to Chesapeake, Mrs. Grigsby worked for Commander Aircraft Company and Deloitte & Touche, LLP in various accounting and supervisory roles. She earned a Bachelor of Science in Accounting from Oklahoma State University and a Masters of Business Administration with an emphasis in finance from Oklahoma City University. Mrs. Grigsby is a Certified Public Accountant and Chartered Global Management Accountant.

Keith Yankowsky joined Ascent Resources in 2016 as Chief Operating Officer. Prior to joining Ascent, Mr. Yankowsky served as Executive Vice President and Chief Operating Officer at Magnum Hunter Resources in Dallas, TX. He previously spent nine years at Chesapeake Energy in a variety of leadership roles, most recently as Vice President of that company’s Appalachia South Business Unit. Mr. Yankowsky gained international experience during his tenure at Burlington Resources. Prior to that, he worked at Conoco Inc. in both Midland and Houston, TX. He earned his Bachelor of Science in Petroleum Engineering at Marietta College and has served as a member of the Society of Petroleum Engineers since 1983.

Mrs. Cook joined Ascent in 2015 as Senior Vice President & Chief Accounting Officer from American Energy Partners where she served as Chief Accounting Officer. Mrs. Cook previously served for 19 years at Chesapeake Energy Corporation, most recently as Vice President and Division Controller - Financial Analysis and Reporting since 2006. During her tenure at Chesapeake, she played a significant role in its filing of over 70 public debt or equity offerings and the initial public offerings of Chesapeake Midstream Partners, LP (later Access Midstream Partners, LP) and the Chesapeake Granite Wash Trust. At Chesapeake, Mrs. Cook was also responsible for corporate financial reporting, including SEC reporting, accounting process and data management, tax and budgeting and forecasting. Prior to joining Chesapeake, she worked as an audit manager for Deloitte & Touche for six years. Mrs. Cook earned a Bachelor of Science in Accounting from the University of Central Oklahoma and is a Certified Public Accountant.

Mr. Johnson joined Ascent in 2015 as Senior Vice President - Midstream and Marketing. He previously spent 18 years working for Chesapeake Energy Corporation where he served as Senior Vice President - Marketing and as President of Chesapeake Energy Marketing, Inc. (CEMI). Prior to Chesapeake, Mr. Johnson worked in multiple land and commercial roles at Enogex, Inc., Delhi Gas Pipeline Corporation, TXO Production Corp. and Gulf Oil Corporation. He earned a Bachelor of Business Administration in Petroleum Land Management from the University of Oklahoma.

Robert W. Kelly II joined Ascent Resources as Senior Vice President - General Counsel and Secretary in October 2015. Previously, Mr. Kelly served as General Counsel for American Energy Partners. Prior to that, he worked in various legal, land and acquisition roles including extended tenures at Chaparral Energy, LLC as Senior Vice President & General Counsel, EOG Resources as Division Land Manager and TXO Production Corp. as District Land Manager. Mr. Kelly earned a Bachelor of Business Administration degree in Petroleum Land Management from the University of Oklahoma, followed by a Juris Doctorate from Oklahoma City University’s School of Law. He is admitted to practice law in Oklahoma and Ohio.

John Adcock is Vice President – Operations at Ascent Resources. With more than 24 years of experience in engineering and management, Mr. Adcock most recently served as Vice President of Chesapeake Energy’s Mid-Continent business unit. Prior to that, he served in a variety of engineering and management roles at BJ Services Company in Texas and New Mexico. Mr. Adcock was the Chairman of the LOGA Technical Committee, the API RP 90-2 Committee, the co-author of the Marcellus Shale Coalition’s Well Completion and Work-Over Operations Best Practices and has served an integral role in the development of internal standards and best practices at each of the companies for which he has worked. He graduated from Texas Tech University with a Bachelor of Science degree in Mechanical Engineering and has been a member of the Society of Petroleum Engineers since 1993.

Dale Cook is Vice President – Accounting at Ascent Resources. He joined Ascent in 2016 from American Energy Partners where he served as Controller. Previously, Mr. Cook held a succession of managerial positions during 19 years of service at Chesapeake Energy Corporation culminating in his leadership role as Vice President – Accounting. Prior to Chesapeake, he served as Senior Accountant at the Haliburton Company in Oklahoma and Texas. Mr. Cook earned a Bachelor of Business Administration degree in Accounting from the University of Oklahoma.

Bryan Ely serves Ascent Resources as Vice President – Environment, Health & Safety (EHS) responsible for all EHS programs including air, water and waste compliance as well as multiple safety programs and initiatives. With more than 26 years of experience in operations and EHS management, Mr. Ely previously worked at Chesapeake Energy in multiple roles, most recently as Director – EHS for the Northern Division. Prior to that, he held management roles at RJR Engineering, LTD, Allied Waste Industries and positions within the Texas Commission on Environmental Quality (formerly known as the Texas Natural Resource Conservation Commission). He also served as EHS Advisor at American Energy Partners. Mr. Ely graduated from Stephen F. Austin State University with a Bachelor of Science in Biology.

Serena D. Evans serves as Vice President – Land for Ascent Resources. In this role, she directs all phases of petroleum land management, including acquisitions and divestitures for the company. Previously, Ms. Evans served as Director of Land at American Energy Partners. Prior to that, she held land management roles in multiple conventional and unconventional United States plays, most recently serving as Land Manager for the Marcellus Shale for Chesapeake Energy. Ms. Evans has also served in various land management roles for TXO Production Corp., Marathon Oil Company and EOG Resources, Inc. Ms. Evans is a Certified Petroleum Landman and earned a Bachelor of Science degree in Business Management from Oklahoma City University. She has also served as a mentor for the Energy Management program at the University of Oklahoma for the past 10 years.

Dan Hensley is Vice President – Exploration and Resource Development at Ascent Resources. He has more than 18 years of Exploration & Production (E&P) experience with an emphasis on operations, production, asset development and project economics. Prior to joining Ascent, Mr. Hensley served in various management positions at Chesapeake Energy culminating in his role as Director – Operations & Technical Services, Engineering Services – Drilling, Completions, Production & Reservoir Engineering. Prior to that, he held various engineering and leadership positions at ARCO, Phillips Petroleum and ConocoPhillips. Mr. Hensley holds a Bachelor of Science degree in Chemical Engineering from the University of Oklahoma and Associate of Science degrees in Mathematics and Engineering from Oklahoma City Community College. He is a member of several professional associations including the Society of Petroleum Engineers and the American Institute of Chemical Engineers.

Brad Sheriff joined Ascent Resources as Vice President - Information Technology in 2017. In this role, he is responsible for all aspects of IT at Ascent to enhance business growth, introduce strategic innovations and maintain cyber-security. Previously, Mr. Sheriff served at Permian Resources, LLC as Vice President/IT. Prior to that he spent four years at Chesapeake Energy in a variety of leadership roles, most recently leading the IT security and compliance team. Mr. Sheriff has also served in senior IT leadership roles in healthcare and retail including INTEGRIS Health and Sonic Industries. Mr. Sheriff attended Texas Lutheran University where he earned a Bachelor of Arts degree in Business Administration and played intercollegiate athletics. He serves on the United Way of Central Oklahoma - Technology Committee as well as several other non-profit boards.

James M. Tully is Vice President – Drilling at Ascent Resources. Mr. Tully has 35 years experience in all aspects of drilling, completions, fracturing, well stimulations, well testing and operations in several different basins across the United States. Prior to joining Ascent, he held a variety of engineering and management roles at Southwestern Energy culminating with his position as Drilling Manager – Fayetteville Shale Division where he managed a 25 rig program at its peak. Mr. Tully earned a Bachelor of Science in Petroleum Engineering Technology at Oklahoma State University. He is a member of the Society of Petroleum Engineers and the American Association of Drilling Engineers. Mr. Tully recently served on the board of directors for the Boys and Girls Club of Central Arkansas.

Cheri Shepard is Director – Human Resources at Ascent Resources. As the company’s HR lead, Ms. Shepard develops and implements people strategies, administers compensation and benefits programs and provides leadership support on employee relations and workforce planning. With more than 25 years experience in her field, she most recently served as Director – HR Business Partner at The Williams Companies and Director – Human Resources at Access Midstream. She previously held leadership roles at Chesapeake Energy and Hitachi Computer Products (America) respectively. Ms. Shepard earned a Bachelor of Business Administration in Finance and a Masters of Public Administration from the University of Oklahoma. She is a SHRM Senior Certified Professional (SHRM-SCP), Certified Compensation Professional (CCP) and a Senior Professional in Human Resources (SPHR). Ms. Shepard recently served on the board of directors for the Knowledge Is Power Program (KIPP).