Technical Team


David Mitchell
Vice President, Engineering

David Mitchell was appointed Vice President, Engineering in 2017. Mr. Mitchell is responsible for and oversees all engineering operations and projects. During his time with TransAtlantic Petroleum since 2013, Mr. Mitchell has held positions as Sr. Operations Engineer, Operations Manager, and VP Engineering.

Besides his experience at TransAtlantic Petroleum, Mr. Mitchell started working with Longfellow Energy focusing on conventional and unconventional projects in Oklahoma, Texas and New Mexico in 2016. 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.

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's primary responsibilities are to oversee the safe and efficient operation and development of Tranatlantic Petroleum's 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 was appointed Senior Reservoir Engineer for TransAtlantic Petroleum in 2016. His primary responsibilities include the all aspects of reservoir engineering studies and supporting asset teams to facilitate the execution of operations and asset development. He has held various positions in Completions and Reservoir Engineering for TransAtlantic Petroleum since 2012.

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. Mr. Follis is responsible for and oversees all drilling operations.

Mr. Follis has been in the oil and natural gas industry since 1989 and has served as Vice President of Operations for Longfellow Energy since 2007. Prior to joining Longfellow Energy, Mr. Follis served in several managerial operational roles for 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 475 wells.


Harold Muncy
Vice President, Geosciences

Harold "Lee" Muncy joined TransAtlantic Petroleum in 2014 as Vice President of Geosciences. Mr. Muncy oversees all of the geological and geophysical efforts of TransAtlantic Petroleum. He brings more than 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 Petroleum, 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 Ohio State University. 

Burc Umul
Senior Geoscientist

Burc Umul has served as Senior Geoscientist for TransAtlantic Petroleum since 2012. Mr. Umul's responsibilities  include exploration and development projects in Southeast Turkey, with special focus in Mardin Cretaceous prospects and Selmo Field projects.

Prior to joining TransAtlantic Petroleum, Mr. Umul took over as Head of Geology Department at Thrace Basin Natural Gas Company (TBNG) from 2008 to 2012 and served as the Exploration Team Leader upon TransAtlantic Petroleum's acquisition of Thrace Basin Natural Gas Company (TBNG). From 2002 to 2008, Mr. Umul was Site Geologist at TBNC. Mr. Umul began his career as a Geological Engineer at a local surface investigation company in Turkey in 1997.

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 degree 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.

Prior to joining TransAtlantic Petroleum, Mr. Mitchell worked in various leadership capacities in international oilfield service companies. Mr. Mitchell continues to serve as an Executive Manager of Production Solutions International, an Eastern European focused oilfield service company.

In addition to his international experience, Mr. Mitchell founded and served as President of Viking Coil Tubing, an Permian Basin focused oilfield service company until its sale to Conquest Completion Services, a Warburg Pincus portfolio company, in 2018. Mr. Mitchell founded and serves as the Manager of the General Partner of Red Rock Minerals, LP, an Anadarko Basin focused mineral rights 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 was appointed as Eastern Europe CFO for TransAtlantic Petroleum Turkey in 2016. His management responsibilities include area credit facilities, cash management, statutory accounting, tax, and auditing. Mr. Ulker initially joined TransAtlantic Petroleum in 2010 serving in different areas including management of marketing and trading unit.

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

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 was appointed as Financial Controller in 2017 after joining TransAtlantic Petroleum in 2016. 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 been in the oil and gas industry since 2006.  Prior to joining TransAtlantic Petroleum, he served as the CFO for The Mitchell Group Domestic Oilfield Service Companies, and as 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.