Technical Team


David Mitchell
Vice President, Engineering

David Mitchell joined TransAtlantic Petroleum in 2013.  During his time with the company he has held positions as Sr. Operations Engineer, Operations Manager, and in 2017 VP Engineering.

Prior to joining TransAtlantic, Mr. Mitchell spent the first 8-years of his career with Talisman Energy, where he held various positions in Production, Midstream, Development, and Completions Engineering throughout British Columbia, Alberta, New York, and Pennsylvania.  Additionally, in 2016 David started working with Longfellow Energy focusing on conventional and unconventional projects in Oklahoma, Texas and New Mexico.

Mr. Mitchell holds a BASC. (Engineering) from the University of British Columbia, and is a registered Professional Engineer (Alberta).

Javier Gonzalez
Operation Manager

Javier Gonzalez joined TransAtlantic Petroleum as Operation Manager in early 2017. Mr. Gonzalez primary responsibilities are to oversee the safe and efficient operation and development of the company assets in Turkey, Bulgaria, and the region as well as manage the local technical teams.

Prior to joining TransAtlantic, Mr. Gonzalez served in several managerial and technical roles in Drilling, Completion, and Production Operations at Occidental Petroleum, Shell E&P, and Schlumberger. He has worked in the Permian Basin, South Texas, Venezuela, Mexico, Russia, and the Gulf of Mexico.

Mr. Gonzalez holds a B.Sc. in Petroleum Engineering from The University of Tulsa and a M.B.A. degree from the University of Houston.  He is also an active member of the SPE.

Koray Yilmaz
Senior Reservoir Engineer

Koray Yilmaz, is currently Senior Reservoir Engineer for TransAtlantic Petroleum.  He has held various positions in Completions and Reservoir Engineering for TransAtlantic Petroleum since 2012. His primary responsibilities include the all aspects of reservoir engineering studies and supporting asset teams to facilitate the execution of operations and asset development.

Prior to joining TransAtlantic, Mr. Yilmaz served as Coiled Tubing Engineer for Viking Services where he was heavily involved in horizontal well interventions in the Permian Basin. Before joining Viking, Mr. Yilmaz served in various production and reservoir engineering roles for independent oil/gas producers in Turkey. He also serves as a technical reviewer for Journal of Natural Gas Science and Engineering.

Mr. Yilmaz holds B.S. and M.S. degrees in Petroleum Engineering from Istanbul Technical University and an M.B.A. degree from The University of Texas Austin McCombs School of Business.

James Follis
Drilling Manager

James Follis has served as Drilling Manager for TransAtlantic Petroleum since 2014.  He has served as Vice President of Operations for Longfellow Energy since 2007 and has more than 25 years of experience in the oil and natural gas industry.

Prior to joining Longfellow Energy, Mr. Follis served in several managerial operational roles over 18 years with Riata Energy, Inc. and Lariat Services. He managed Riata’s operations in Texas, Oklahoma, Colorado, Utah, Wyoming and Kentucky and assumed the role of Vice President of Operations in 2000. In his career, he has drilled more than 350 wells.


Lee Muncy
Vice President, Geosciences

Lee Muncy joined TransAtlantic Petroleum in 2014 as Vice President of Geosciences.  Mr. Muncy oversees all of the geological and geophysical efforts of the company. He brings 35+ years of geological experience in the oil and natural gas industry, where he has focused on exploration, exploitation and worldwide transactions.

Prior to joining TransAtlantic, Mr. Muncy served as Vice President, Exploration for the Bass Companies, a group of Fort Worth, Texas-based independent oil and natural gas exploration and production companies, from 2000 to 2012. He began his career as a geologist with Mobil Oil Corporation and served as Exploration Manager for Fina Oil & Chemical Company and Vice President of Exploration and Land for TransTexas Gas Corp.

Mr. Muncy holds a B.S. degree and an M.S. degree in Geology & Mineralogy from The Ohio State University. 

Burc Umul
Senior Geoscientist

Burc Umul has served as Senior Geoscientist for TransAtlantic Petroleum since 2011.  Mr. Umul's responsibilities  include exploration and development projects in Southeast Turkey. Beginning his career as a Geologist with Thrace Basin Natural Gas Company (TBNG) in 2002, Mr. Umul served as the Exploration Team Leader upon TransAtlantic's acquisition of TBNG.

Mr. Umul holds a B.S. degree in Geological Engineering from Hacettepe University and is a member of AAPG and the Turkish Association of Petroleum Geologists.

Sherrie Peña Cawthon
Senior Geoscientist

Sherrie Peña Cawthon joined TransAtlantic Petroleum in 2014 as a Senior Geoscientist.  Mrs. Cawthon’s responsibilities include exploration and development projects focused on the Molla region of Southeast Turkey.

Prior to joining TransAtlantic Petroleum, Mrs. Cawthon worked for Pioneer Natural Resources for 10 years.  During that time, she worked various assets and her experience includes both Exploration and Development Geology with focus on a wide range of plays such as the Gulf of Mexico shelf, Deepwater West Africa, Marble Falls Clastics and Barnett Shale in the Fort Worth Basin, as well as the Edwards and Eagle Ford trends in South Texas.

Mrs. Cawthon holds a M.Sc. of Geosciences and a Certification in Remote Sensing from The University of Texas at Dallas and a B.A. degree in Geology from Southern Methodist University.  She is also a member of the AAPG.

Business Development, Land and Regulatory

Noah M. Mitchell 4th
Vice President

Noah M. Mitchell 4th has served as Vice President of TransAtlantic Petroleum since 2014. He serves as Director of Business Development for Viking Services and initiated its expansion into Turkey, Iraq, Poland and Hungary. Mr. Mitchell is responsible for oversight of the operational and financial performance of the company.

Mr. Mitchell also serves as a Founder and President of Viking Coil Tubing, an oilfield service company operating in Texas, New Mexico, and Oklahoma, with a primary focus on formulating and implementing strategic plans of the company.

Mr. Mitchell holds a B.S. degree from Southern Methodist University. 

Finance and Accounting

Veli Ozan Ülker
Eastern Europe Chief Financial Officer

Ozan Ulker joined TransAtlantic Petroleum in 2010 serving in different areas including management of marketing and trading unit. In 2016, he was appointed as Eastern Europe CFO for TransAtlantic Petroleum Turkey. His management responsibilities include area credit facilities, cash management, statutory accounting, tax, and auditing.

Prior to joining TransAtlantic, Mr. Ulker worked in different industries including Banking, FMCG, Retail and Energy Trading in multinational companies, Citibank from 2004-2007, Nestle and Fiba Group from 2008-2010.

Mr. Ulker has a Bachelor’s degree in Political Sciences from Istanbul University and holds Advanced Level Certificate from Capital Market Board of Turkey.

Matthew Hancock
Financial Controller

Matthew Hancock joined TransAtlantic Petroleum in 2016 and was appointed as the Financial Controller in 2017. Mr. Hancock’s responsibilities include internal and external financial reporting, internal controls, transaction handling and the development of the Dallas accounting staff.

Mr. Hancock has 13+ years of experience in the Oil and Gas industry.  Prior to joining TransAtlantic Petroleum, he served as the CFO for The Mitchell Group Domestic Oilfield Service Companies, and as a Consulting Manager at Grant Thornton, LLP in its Houston, Texas Business Advisory Practice.    

Mr. Hancock holds a Master of Business Administration degree and a Bachelor of Accountancy from New Mexico State University.