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The Team
NSAI specializes in projects encompassing multiple disciplines. Our technical staff includes reservoir and operations engineers, petrophysicists, and geoscientists who are generally cross-trained in geology and geophysics. We also employ staff specializing in geologic modeling, reservoir simulations, complex computer mapping, and non-routine time-to-depth conversion. We apply the right combination of people, expertise, and technology to each assignment.
Our present organization consists of approximately 55 reservoir engineers, geoscientists, and petrophysicists; 70 engineering and geologic analysts; and additional support staff. Our technical staff is carefully recruited from the industry’s most qualified candidates. The average experience level of these individuals exceeds 20 years, including 5 to 15 years with a major oil company. Most of our engineers, geoscientists, and petrophysicists obtained their initial training and experience with BP, British Gas, Chevron, ConocoPhillips, or ExxonMobil. We recruit only those with academic excellence, sound judgment, intuitive skills, relevant experience, and an understanding of the critical relationship that exists between petroleum and the financial industry.
Executive Leadership
Richard B. Talley, Jr.
Chairman and Chief Executive Officer
Houston
Rick Talley joined NSAI in 2004 and had over 23 years of oil and gas experience when he was promoted to Chief Executive Officer in 2022. He has significant experience with preparing reserves evaluations for conventional and unconventional assets in most major onshore United States producing basins, as well as Gulf of America and international properties. Rick began his career at ExxonMobil Production Company and has a B.S. in Mechanical Engineering from University of Oklahoma and an M.B.A. from Tulane University. Rick is a licensed Professional Engineer in the States of Texas and Louisiana, a member of the Society of Petroleum Evaluation Engineers (SPEE) and the Society of Petroleum Engineers (SPE), and Chair of the Energy Institute at the University of Oklahoma.
Eric J. Stevens
President and Chief Operating Officer
Dallas
Eric Stevens joined NSAI in 2007 and has extensive experience overseeing complex projects and leading multidisciplinary teams in the evaluation of oil and gas assets worldwide. His work has focused particularly on projects throughout Central and South America, West Africa, and the United States. Prior to joining NSAI, Eric began his career with ExxonMobil Development Company as a reservoir engineer and development planner, where he worked on major projects in Russia and West Africa. Eric holds a B.S. in Mechanical Engineering from Brigham Young University and is a licensed Professional Engineer in the State of Texas. He is an active member of the Society of Petroleum Evaluation Engineers (SPEE), the Society of Petroleum Engineers (SPE), the ADAM Energy Forum, and the Dallas Petroleum Club, where he currently serves on the Board of Directors.
Senior Management
Lily W. Cheung
Senior Vice President
Engineering • Houston
M.B.A., University of Texas at Austin, 2007; B.S. in Mechanical Engineering, Massachusetts Institute of Technology, 2003. Prior to joining NSAI in 2007, Lily worked at ExxonMobil Production Company as a Senior Engineer supporting the Gulf of America and Piceance Basin. Her experience includes conventional and unconventional reserves and resources evaluations, drilling and workover prospect evaluation, volumes forecasting, operations engineering, property evaluations for acquisitions and divestitures, economic evaluations, artificial lift and well stimulation studies, and reserves-based lending analysis. Lily is a licensed Professional Engineer in the State of Texas.
John R. Cliver
Senior Vice President
Engineering • Houston
M.B.A., University of Texas at Austin, 2008; B.S. in Chemical Engineering, Rice University, 2004. Prior to joining NSAI in 2009, John was a Staff Reservoir Engineer with ExxonMobil Production Company. John has evaluated reserves, resources, and development plans for onshore and offshore assets worldwide, with extensive experience in deepwater environments in particular. He leverages his expertise in reservoir, well, and facility modeling to support his assessments where appropriate.
P. Scott Frost
Senior Vice President and Chief Financial Officer / Executive Committee
Engineering • Dallas
Scott Frost has been with NSAI since 1984 and has over 40 years of oil and gas evaluation experience. He was promoted to CFO in 2002. Scott has extensive experience in multi-disciplinary large project management, deepwater field evaluations, equity determinations, and probabilistic analysis of exploration prospects and new discoveries. He has evaluated oil and gas fields throughout the world with particular emphasis on all United States producing basins, the North Sea, Southeast Asia, and Brazil. Scott began his career at Exxon Company, U.S.A. and has an M.B.A. in Finance from Tulane University and a B.E. in Mechanical Engineering from Vanderbilt University.
Justin S. Hamilton
Senior Vice President
Engineering • Dallas
M.B.A, University of Texas at Austin, 2007; B.S. in Mechanical Engineering, Brigham Young University, 2000. Prior to joining NSAI in 2004, Justin was a Senior Project Engineer with ExxonMobil Production Company. His specific areas of expertise include reserves and resources estimation, property evaluation for sales and acquisitions, field studies, economic evaluations, and oil and gas reserves certifications. He has evaluated reserves and resources for oil and gas fields throughout the world, with particular emphasis on onshore and offshore basins in the United States, Mexico, South America, and West Africa.
John G. Hattner
Senior Vice President / Executive Committee
Geology and Geophysics • Dallas
M.B.A., Saint Mary’s College of California, 1989; M.S. in Geological Oceanography, Florida State University, 1980; B.S. in Geology, University of Miami, Florida, 1976. John joined NSAI in 1991. He was previously a Geophysicist for Chevron Overseas Petroleum, Amoseas Indonesia, and Chevron Petroleum U.K. John has served as the geologic leader on large projects in Mexico and Bolivia, a significant number of coalbed methane evaluations in domestic and international basins, and several evaluations for large international independents covering their worldwide exploration portfolios in Australia, Southeast Asia, the United States, Gulf of America deepwater, the North Sea, and West Africa.
Nathan C. Shahan
Senior Vice President
Engineering • Dallas
M.Eng. in Petroleum Engineering, Texas A&M University, 2007; B.S. in Petroleum Engineering, Texas A&M University, 2002. Nathan joined NSAI in 2007 and has recently been focused on evaluating unconventional reserves in the Anadarko, Delaware, Midland, and Williston Basins and Eagle Ford, Haynesville, and Utica plays. His prior work at NSAI includes international and domestic CBM and conventional gas reserves and resources estimation and enhanced oil recovery reserves evaluations in the Permian and San Joaquin Basins. He has prepared detailed technical reports for public offerings on the Hong Kong, London, Singapore, and Toronto stock exchanges and has assisted clients in public listings on the New York Stock Exchange. Before joining NSAI, he worked for Anadarko Petroleum Corporation in production and reservoir engineering roles.
Joseph J. Spellman
Senior Vice President / Executive Committee
Engineering • Dallas
B.S. in Civil Engineering, University of Wisconsin – Platteville, 1980. Joe has been with NSAI since 1989 and has over 45 years of oil and gas evaluation expertise. Joe’s geographic areas of expertise include all major United States producing basins, the Gulf of America, the Middle East, Africa, Southeast Asia, the northwest shelf of Australia, Papua New Guinea, the Former Soviet Union, Eastern Europe, and the United Kingdom. His work includes project coordination and property evaluations for use by clients in arranging financing and evaluating potential acquisitions or sales, with a focus on project finance. Joe has also led several major gas certifications used for LNG and pipeline projects in addition to leading multiple equity redetermination projects. Joe was a Senior Supervising Engineer with Exxon Company, U.S.A. before joining NSAI.
Geoscience, Engineering, and Petrophysics Experts
Jose A. Aburto
Vice President
Engineering • Houston
B.S. in Chemical Engineering, University of Illinois at Urbana-Champaign, 2009. Prior to joining NSAI in 2018, Jose worked at ExxonMobil as a Senior Reservoir Engineer and development planner supporting assets in Russia, the Middle East, and Guyana. His experience includes oil and gas reserves and resources estimation, field development planning, reservoir simulation modeling, and property evaluations for acquisitions and divestitures. Jose is a licensed Professional Engineer in the State of Texas. Jose speaks Spanish fluently.
Michael B. Begland
Senior Advisor
Engineering • Dallas
B.S. in Chemical Engineering, Ohio State University, 1983. Mike joined NSAI in 1993 after serving as a Staff Engineer with Exxon Company, U.S.A. He performs technical reservoir engineering and economic analyses for domestic and international projects, including reserves certifications and asset sale and acquisition packages. Mike has focused on domestic resource play evaluations for the past 10 years. He has specific technical expertise with gas storage and gas injection EOR projects.
James D. Berry
Vice President
Engineering • Dallas
B.S. in Chemical Engineering, University of Oklahoma, 2008. Prior to joining NSAI in 2014, James worked at ExxonMobil Development and ExxonMobil Production companies as a Senior Engineer for new developments in the Gulf of America as well as for development and production projects in the North Field in Qatar. His work includes oil and gas reserves and resources estimations, depletion planning and optimization, drilling and workover prospect evaluations, reservoir simulation modeling, and economic evaluations using deterministic and probabilistic methodologies.
Tony P. Blanker
Petroleum Engineer
Engineering • Houston
B.S. in Petroleum Engineering and B.S. in Energy Business Finance, The Pennsylvania State University, 2018. Prior to joining NSAI, Tony held various reservoir engineering positions with ExxonMobil supporting assets in Guyana, Brazil, and North Dakota. His experience includes oil and gas reserves estimation, reserves audits, fair market value evaluations, economic evaluations, property evaluations for acquisitions and divestitures, and reservoir simulation modeling. His main geographic areas of expertise are the Appalachian Basin and Brazil. Tony is a licensed Professional Engineer in the State of Texas and a member of the Society of Petroleum Engineers (SPE). Tony speaks Portuguese fluently and is conversational in Spanish.
Michelle L. Burnham
Vice President and Technical Advisor
Engineering • Dallas
M.B.A., University of Texas at Austin, 2011; B.S. in Electrical Engineering, Brigham Young University, 2006. Before joining NSAI in 2015, Michelle worked at Anadarko Petroleum Corporation and ExxonMobil Production Company as a Senior Reservoir Engineer. Her experience includes oil and gas reserves estimation, drilling and workover prospect evaluation using analytical modeling and reservoir simulation, property evaluations for sales and acquisitions, volumes forecasting, surveillance, and economic evaluations using deterministic and probabilistic methodologies. She is a licensed Professional Engineer in the State of Texas, a Registered Professional Engineer in Queensland (RPEQ) in Australia, and a member of the Society of Petroleum Engineers (SPE).
Wayne K. Burton II
Vice President and Senior Technical Advisor
Engineering • Houston
B.S. in Chemical Engineering, University of Nevada, 2001. Prior to joining NSAI in 2005, Wayne was a reservoir engineer for Amerada Hess Corporation and ExxonMobil Production Company. Wayne has performed reserves and resources evaluations and provided advisory services on conventional and unconventional properties in most emerging and major producing basins both onshore and offshore North America and in international basins throughout Europe, Australia, India, South America, and Africa. His experience includes reserves estimation, integrated production modeling, enhanced recovery projects, deliverability studies and optimizations, prospect evaluations, and economic evaluations utilizing both deterministic and probabilistic methodologies.
Andres F. Castaño
Vice President and Technical Advisor
Engineering • Dallas
M.S. in Petroleum Engineering, University of Oklahoma, 2009; B.S. in Petroleum Engineering, Universidad Nacional de Colombia, 2004. Prior to join NSAI in 2013, Andres worked at BP, where he held various reservoir engineering positions supporting operations in North America and Colombia. His work includes oil and gas reserves estimation, reserves audits, technical due diligence evaluations for potential acquisitions, field studies, contingent and prospective resources evaluations, sales gas deliverability studies, and economic evaluations. His main geographical area of expertise is Latin America; he speaks Spanish fluently and is conversational in Portuguese. Andres is a Licensed Petroleum Engineer in the State of Texas and the Republic of Colombia, a member of the Society of Petroleum Evaluation Engineers (SPEE), and a member of the Society of Petroleum Engineers (SPE).
Daniel C. Clements
Petroleum Engineer
Engineering • Dallas
M. Eng. in Petroleum Engineering, University of North Dakota, 2024; B.S. in Computer Science, The University of Texas at Arlington, 2009. Daniel joined NSAI in 2013 as a Petroleum Analyst and moved to the role of Petroleum Engineer in 2025. His work includes unconventional reserves estimation, production forecasting, economic evaluations, and machine learning modeling. He is a member of the Society of Petroleum Engineers (SPE).
Matt T. Dalka
Vice President and Team Leader
Engineering • Dallas
B.S. Chemical Engineering / Engineering and Public Policy, Carnegie Mellon University, 2005. Matt Dalka joined NSAI in 2013 and has extensive experience coordinating oil and gas reserves evaluations, conducting property evaluations for sales and acquisitions, and performing economic evaluations using deterministic and probabilistic methodologies. He has extensive experience in all of the unconventional basins of the United States, with a particular expertise in the Haynesville basin. Prior to joining NSAI, Matt began his career with ExxonMobil in a variety of technical and supervisory roles within reservoir, development planning, facilities, and process engineering. Matt is a licensed Professional Engineer in the State of Texas and is a member of the Society of Petroleum Engineers (SPE).
James A. Davidson
Vice President and Senior Technical Advisor
Petrophysics • Dallas
Ph.D. in Petroleum Engineering, University of Texas at Austin, 1998; M.S. in Petroleum Engineering, University of Texas at Austin, 1993; B.S. in Petroleum Engineering, Texas Tech University, 1979. Jim was a geoscientist with Landmark Graphics Corp. and a Senior Reservoir Engineer with Atlantic Richfield Indonesia Inc. before joining NSAI in 1998. Jim has performed petrophysical evaluations for wells located in most of the major petroleum provinces of the world.
Ruurdjan (Rudi) de Zoeten
Vice President and Technical Advisor
Geology and Geophysics • Dallas
M.A. in Geology, University of Texas, 1988; B.S. in Geology, University of Wisconsin, 1985. Rudi joined NSAI in 2008 with 19 years of worldwide exploration and development experience, primarily with Unocal Corporation. He performs integrated technical analyses and geocellular modeling to estimate reserves and resources for conventional and unconventional oil and gas properties. His areas of expertise include 3-D seismic interpretation, geological mapping, reservoir characterization, prospect evaluations, and reservoir engineering in terrestrial, shelf, and deepwater plays in the Gulf of America, South America, West Africa, Asia, and onshore United States.
Helena P. Doran
Petroleum Engineer
Engineering • Houston
B.S. in Chemical Engineering, The University of Texas at Austin, 2013. Before joining NSAI, Helena held various reservoir engineering and planning positions with ExxonMobil and XTO Energy supporting assets in Angola (deepwater), Oklahoma, Texas, and New Mexico. Her experience includes business planning, depletion planning and optimization, production surveillance, reserves and resources estimation, and reservoir simulation modeling.
Nicholas M. Gnyra
Vice President
Engineering • Dallas
B. Sc., Petroleum Engineering, University of Alberta, 2004. Prior to joining NSAI in 2013, Nick worked at Encana Corporation in a variety of technical and supervisory roles within reservoir, development, production, and facilities engineering, along with business development and strategic planning. Nick has experience in most of the major producing basins across Canada and throughout the United States. His work includes project coordination, oil and gas reserves and resources estimations, field studies, due diligence for acquisitions and divestitures, economic evaluations, and production optimization. He is experienced in lithium resource reporting, mineral and royalty evaluations, and fair market value determination. Nick is a Licensed Petroleum Engineer in the State of Texas and the Province of Alberta, a member of the Society of Petroleum Evaluation Engineers (SPEE), and a member of the Society of Petroleum Engineers (SPE).
Kyle B. Haft
Vice President
Engineering • Houston
Engineering • Houston
M. Eng. in Petroleum Engineering, Texas A&M University, 2016; B.S. in Civil Engineering, Georgia Institute of Technology, 2011. Before joining NSAI in 2019, Kyle held various reservoir engineering positions with ExxonMobil and XTO Energy for assets in Wyoming, New Mexico, Gulf of America, and Guyana. His experience includes reserves and resources estimation, drilling and workover opportunity evaluations, reservoir simulation modeling, depletion planning and optimization, production surveillance, and economic evaluations. Kyle frequently employs reservoir simulation modeling in support of reservoir characterization and field expansion assessments of natural gas storage fields.
Kathy J. Hartman
Senior Associate
Engineering • Dallas
B.S. in Chemical Engineering, Texas A&M University, 1980. Kathy worked for Mobil affiliates worldwide in a variety of positions, and later as an independent consultant, before joining NSAI in 2005. She has conducted reservoir engineering analyses for domestic and international projects including equity determinations, field studies, and reserves certifications of oil and gas properties, with specific expertise in reservoir simulation.
Michelle F. Herrera
Vice President and Team Leader
Geology and Geophysics • Dallas
B.S. in Geosciences, University of Texas at Dallas, 2002. Prior to joining NSAI in 2013, Michelle was a geophysicist with Encana Oil & Gas, Inc. (now Ovintiv Inc.) and Hunt Oil Company. She specializes in the integration of geologic, geophysical, and engineering data for reserves and resources assessments, including seismic data interpretation, well log correlation and analysis, and geocellular modeling. Michelle has over 20 years of experience with both conventional and unconventional plays in the United States, Africa, Mexico, Southeast Asia, Australia, South America and Europe.
Chad E. Ireton
Vice President
Engineering • Houston
B.S. in Petroleum Engineering, The University of Tulsa, 2000. Prior to joining NSAI in 2012, Chad held multiple reservoir engineering positions with ExxonMobil Production Company and worked several years as a Drilling Engineer with ExxonMobil Development Company. His experience includes project coordination, conventional and unconventional reserves and resources evaluations, field studies, development optimization projects, production forecasting, property evaluations for acquisitions and divestitures, economic evaluations, and reserves-based lending analysis.
Akshay N. Jayaram
Vice President
Engineering • Dallas
M. Eng. in Petroleum Engineering, Texas A&M University, 2017; B.S. in Mechanical Engineering, Carnegie Mellon University, 2009. Prior to joining NSAI in 2018, Akshay held various reservoir engineering positions with ExxonMobil supporting assets in the Middle East, Guyana, Russia, and Gulf of America. His experience includes oil and gas reserves and resources estimation, field development planning, reservoir simulation modeling, well testing, and economic evaluations using deterministic and probabilistic methodologies.
Benjamin W. Johnson
Vice President and Team Leader
Engineering • Dallas
B.S. in Petroleum Engineering, Texas Tech University, 2005. Benjamin was an operations engineer at Merit Energy Company before joining NSAI in 2007. He has evaluated properties on six continents, with a domestic focus on unconventional plays in the Rockies. His client base ranges from small independents to government agencies around the world. Benjamin works projects with operators, non-operators, and capital providers seeking reserves evaluations and technical expertise for year-end reports or potential acquisitions/divestitures.
Alexander V. Karpov
Vice President and Technical Advisor
Engineering • Houston
B.S. in Geology, State Academy of Oil and Gas, Moscow, 1992; M.S. in Petroleum Engineering, Texas A&M University, 2001. Alex was a reservoir engineer with BP for 7 years before joining NSAI in 2008; before that he worked for 7 years in petroleum exploration and production in Western Siberia. His background includes conventional and unconventional reserves assessments, production forecasting, nodal analysis, enhanced recovery and helium project evaluations. Alex is a licensed Professional Engineer in the State of Texas and is a member of the Society of Petroleum Engineers (SPE).
Michael J. Kingrey
Vice President and Technical Advisor
Engineering • Dallas
B.S. in Chemical Engineering, Texas A&M University, 2009. Michael started his career with ExxonMobil, gaining technical experience in the reservoir, production, and completion engineering disciplines with a focus on West Africa. He also served as a production surveillance and optimization advisor to ExxonMobil’s global affiliates and NOC partners before joining NSAI in 2015. He has extensive experience in deterministic reserves evaluation and cash flow modeling for reserves certifications, transaction due diligence, and fair market valuations for both domestic and international oil and gas assets.
William J. Knights
Vice President and Senior Technical Advisor
Geology and Geophysics • Dallas
M.S. in Geology, Texas Christian University, 1984; B.S. in Geology, Texas Christian University, 1981. Bill worked as an independent geologist, evaluating domestic and international exploration and development projects, before joining NSAI in 1991. Since 2002 he has had extensive experience in all the productive and emerging unconventional shale plays in the United States and Canada and in many prospective unconventional plays internationally. He has been involved in the estimation and classification of hydrocarbon volumes from prospective and contingent resources through maturation to proved, probable, and possible reserves in both unconventional and conventional reservoirs. Bill has also been active in domestic and international expert testimony.
Michael F. Krehel, Jr.
Vice President and Senior Technical Advisor
Engineering • Dallas
B.S. in Petroleum and Natural Gas Engineering, The Pennsylvania State University, 1983. Mike was a Production Engineer/Asset Team Leader at Conoco Inc. and later Operations Manager at Mueller Engineering Corp. before joining NSAI in 1998. Mike performs reservoir engineering and economic analyses for domestic and international projects, including reserves certifications and asset acquisition evaluations. He has an extensive background in surface and subsurface operations; areas of expertise include well completions and workovers and production and facility optimization. Mike is also active in dispute resolution, including litigation, expert witness testimony, and mediation/arbitration.
Richard F. Krenek II
Vice President and Team Leader
Engineering • Dallas
B.S. in Chemical Engineering, University of Oklahoma, 1986. Rick joined NSAI in 1990 after starting his career with Exxon Company, U.S.A. His work at NSAI has included oil and gas reserves and resources estimations, property evaluations, and advisory for properties located throughout the United States and in over 40 other countries throughout Europe, Asia, Africa, Australia, and the Americas. Rick has performed international expert testimony work and has led a number of large, complex field studies and equity determinations. Rick is a Licensed Professional Engineer in the State of Texas. He has been given the distinction of Honorary Lifetime Member of the Society of Petroleum Evaluation Engineers (SPEE), an organization in which he has served in many committee and leadership positions over two decades, including President, Executive Committee, Board of Directors, and Council of Past Presidents. Rick was instrumental in developing SPEE’s 2024 Monograph 5 – A Practical Guide to Type Well Profiles and has been actively conducting two-day immersion classes on Monograph 5 content throughout the Americas. Rick is a lifetime member of the Society of Petroleum Engineers (SPE), has previously served on SPE’s Oil and Gas Reserves Committee (OGRC), and is currently a member of the SPE OGRC’s PRMS 2028 Update Committee.
Jess C. Kweh
Petroleum Engineer
Engineering • Dallas
M.B.A., Coventry University, 2019; B.S. in Petroleum Engineering, Universiti Teknologi PETRONAS, 2016. Prior to joining NSAI in 2025, Jess held various reservoir engineering positions with PETRONAS supporting assets in Asia and the Middle East. She has recent involvement in evaluations in North America, South America, and West Africa. Her experience includes annual oil and gas reserves and resources estimation, field development studies, property evaluations for acquisitions and divestiture, and production surveillance.
Neil H. Little
Vice President and Team Leader
Engineering • Houston
M.B.A., University of Houston, 2007; B.S. in Chemical Engineering, Rice University, 2002. Before originally joining NSAI in 2006, Neil worked at ExxonMobil Production Company as a Senior Reservoir Engineer. Neil rejoined NSAI in 2011 after spending 3 years at MEI, LLC as a senior process engineer working on midstream and LNG projects. His experience includes property evaluations for reserves reporting to government and financial institutions, sales and acquisitions evaluations, and prospect evaluation. His specific areas of expertise include international evaluations with complex financial analysis and unconventional hydrocarbon evaluations.
Zachary R. Long
Vice President and Senior Technical Advisor
Geology and Geophysics • Houston
M.S. in Geophysics, Texas A&M University, 2005; B.S. in Petroleum Geology, University of Louisiana at Lafayette, 2003. Before joining NSAI in 2007, Zach worked as a Petrel reservoir modeling consultant for Schlumberger. During his time at NSAI, Zach has continued to apply his expertise in reservoir modeling for the purposes of field studies, reserves and resources estimation, and CCUS applications. His skill set also includes performing geologic and geophysical evaluations of onshore and offshore reservoirs through seismic interpretation and attribute analysis, geologic mapping, reservoir characterization, and probabilistic analysis. Zach has experience in numerous basins, both domestic and international.
Shu Luo
Petroleum Engineer
Engineering • Houston
Ph.D. in Petroleum Engineering, University of Tulsa, 2013; M.S. in Petroleum Engineering, University of Tulsa, 2010; B.S. in Petroleum Engineering, China University of Petroleum Beijing, 2008. Before joining NSAI, Shu held a variety of reservoir engineering and team lead roles at ExxonMobil and PetroTel, working on assets in Guyana, Canada East, Brazil, Permian, and other international fields. His expertise includes reserves and resources estimation, field development planning, reservoir modeling and simulation, well testing and economic analysis. Shu has authored numerous technical publications and served as a reviewer for multiple industry journals. In 2015, he was awarded the SPE Cedric K. Ferguson Medal, which recognizes professional achievement in petroleum engineering.
Joseph M. Mello
Vice President and Team Leader
Engineering • Houston
B.S. in Chemical Engineering, Rice University, 2010. Joe joined NSAI in 2015 after working over five years as a Reservoir Engineer at ExxonMobil Production Company. Joe has worked extensively in the offshore deepwater environment, where he leverages significant simulation experience to understand complex behavior. He also employs his simulation expertise to evaluate reservoirs for carbon sequestration projects.
Charles L. Melvin
Petroleum Engineer
Engineering • Dallas
B.S. in Chemical Engineering, North Carolina A&T State University, 2010. Charles joined NSAI in 2023 after working at BKV Corporation and ExxonMobil. Prior to joining NSAI, he held various reservoir engineering positions supporting unconventional assets within the United States. His primary experience includes reserves and resources estimation, depletion planning and optimization, valuations for M&A and Joint Ventures, evaluating recompletions in horizontal wells, and economic evaluations using deterministic and probabilistic methodologies. He is a licensed Professional Engineer in the state of Texas and a member of the Society of Petroleum Engineers (SPE).
Derek F. Newton
Senior Associate
Engineering • Houston
M.S. in Petroleum Engineering, Strathclyde University, Scotland, 1986; B.S. in Mechanical Engineering, University College Cardiff, Wales, 1983. Derek was a Principal Petroleum Engineer and Technical Manager for BG plc before joining NSAI in 1997. Derek uses his expertise with reservoir simulation on field development, gas storage, equity, and enhanced recovery project evaluations. He specializes in reservoir characterization and integration of geological and petrophysical data, usually involving simulation models scaled up from geo-cellular geological models.
Matthew D. Pankey
Vice President
Engineering • Houston
B.S. in Chemical Engineering, Auburn University, 2012. Before joining NSAI in 2019, Matt held various reservoir and production engineering positions with ExxonMobil for assets in California, Wyoming, and Central Africa. His experience includes reserves assessments, economic analysis, production surveillance and optimization, workover execution, and facilities design. Matt’s specific areas of expertise include unconventional oil and gas evaluations, surface and subsurface operations, and carbon capture and sequestration projects. He is a licensed Professional Engineer in the state of Texas and a member of the Society of Petroleum Engineers (SPE).
Connor B. Riseden
Vice President and Team Leader
Engineering • Houston
M.B.A., Tulane University, 2005; B.S. in Petroleum Engineering, Texas A&M University, 2001. Connor joined NSAI in 2006 after working as a Senior Engineer with ExxonMobil Production Company. During his career at NSAI, Connor has focused extensively on the evaluation of unconventional resources throughout the United States. Beginning with early development in the Barnett and Fayetteville Shales, which helped launch the unconventional resources revolution, he has gained significant experience applying reserves definitions and evaluation methodologies to unconventional developments as the technologies, development strategies, and industry practices have continued to evolve. Connor also has extensive experience evaluating conventional oil and gas developments throughout the Lower 48, including unique and technically complex projects such as a fireflood enhanced oil recovery project in northern Louisiana and a tertiary recovery project in Florida. More recently, he has served as an expert in oil and gas litigation matters, providing technical analysis, expert opinions, and testimony. Connor is a licensed Professional Engineer in the State of Texas and currently serves as a member of the Society of Petroleum Evaluation Engineers (SPEE) International Board of Directors.
Edward C. Roy III
Vice President and Team Leader
Geology and Geophysics • Houston
M.S. in Geology, Texas A&M University, 1996; B.S. in Geology, Texas Christian University, 1992. Ed has significant experience in evaluating development projects, primarily in the Gulf of America and West Africa. Before joining NSAI in 2008, he was a Senior Geologist with Marathon Oil Company. His skills include deepwater stratigraphy, seismic interpretation, attribute analysis, geologic mapping and modeling, reservoir characterization, and probabilistic analysis.
Jason C. Sanford
Geoscientist
Geology and Geophysics • Dallas
M.S. in Geological Sciences, The University of Texas at Austin, 2015; B.A. in Geology and Spanish (magna cum laude), Middlebury College, 2010. Prior to joining NSAI in 2023, Jason held various earth science and advisory positions at Chevron and independents in the Gulf of America, Neuquén, Permian, Appalachian, and Anadarko basins. His skills include seismic interpretation, well log analysis and correlation, reservoir description and characterization, deterministic and probabilistic volumetric estimation, and risk assessment.
Matt J. Sasso
Petroleum Engineer
Engineering • Dallas
B.S. in Petroleum Engineering, Texas A&M University, 2015. Prior to joining NSAI in 2024, Matt held various reservoir and completions engineering positions with Pioneer Natural Resources and Matador Resources Company. His experience includes hydraulic fracturing and wireline operations, workover and fishing execution, oil and gas reserves and resources estimation, property evaluations for acquisitions and divestitures, field development planning, volumes forecasting, and economic evaluations using deterministic and probabilistic methodologies. Matt is a licensed Professional Engineer in the State of Texas.
C. Ashley Smith
Vice President and Team Leader
Engineering • Houston
B.S. in Petroleum Engineering, University of Missouri-Rolla, 2000. Ashley has been a petroleum engineering consultant at NSAI since 2006. His work primarily includes independent audits and evaluations of oil and gas assets for the purpose of arranging for investment in the United States and worldwide equity markets. In addition, he provides evaluations for potential acquisitions and divestitures, conducts efficiency and process reviews, and coordinates projects. While his experience spans North and South America, Europe, and Africa, his specific geographic areas of expertise include deepwater West Africa and the Gulf of America, as well as onshore Alaska and California in the United States. His technical expertise includes estimation of oil and gas reserves, reserves maturation, reservoir development planning, and reservoir simulation modeling. Prior to joining NSAI, Ashley worked at ExxonMobil within both their Development Company and Production Company organizations.
Brandon C. Tang
Petroleum Engineer
Engineering • Dallas
M.S. in Petroleum Engineering, University of Texas at Austin, 2018; B.S. in Petroleum Engineering, University of Texas at Austin, 2016. Prior to joining NSAI in 2026, Brandon held several reservoir engineering roles with SLB, where he consulted clients across a range of reservoir characterization, simulation, and development-planning challenges in both international assets as well as unconventionals. His experience includes reservoir simulation, probabilistic modeling, workflow optimization, and field development planning.
Lauren P. Vernon
Vice President and Technical Advisor
Engineering • Houston
M.Eng. in Petroleum Engineering, Texas A&M University, 2010; B.A. in Anthropology, Baylor University, 1998. Lauren joined NSAI in 1999 as a petroleum analyst and in 2010 transitioned into the role of reservoir engineer. Her experience includes reserves assessment, production forecasting, and economic evaluations using deterministic and probabilistic methodologies.
Ryan J. Wagner
Petroleum Engineer
Engineering • Houston
M.S. in Petroleum Engineering, University of Texas at Austin, 2020; B.S. in Petroleum Engineering, The Pennsylvania State University, 2017. Prior to joining NSAI in 2024, Ryan was a reservoir engineer with ExxonMobil primarily supporting development projects in Guyana as well as various assets in Angola, Russia, and Wyoming. His experience includes reservoir simulation modeling, reserves and resources estimation, field development and depletion planning, and economic evaluations. He is a licensed Professional Engineer in the state of Texas and a member of the Society of Petroleum Engineers (SPE).
Luke F. Wilson
Geoscientist
Geology and Geophysics • Dallas
M.S. Earth and Environmental Sciences, Lehigh University, 2008; B.S. Earth Science, Montana State University, 2005. Prior to joining NSAI in 2026, Luke worked at ExxonMobil in geoscience roles spanning frontier exploration to mature field production and carbon storage. Luke is an expert in integrated subsurface geological and geophysical interpretation at both regional and field scales; reservoir, trap, and seal characterization; and volumetric and risk assessment. Luke’s work has supported significant oil and gas investments at all stages of the asset life cycle in basins onshore and offshore North America, South America, West Africa, Europe, and Southeast Asia. Luke is a licensed Professional Geoscientist in the state of Texas and a member of the American Association of Petroleum Geologists.
Joseph M. Wolfe
Vice President and Team Leader
Engineering • Dallas
M. Eng. in Petroleum Engineering, Texas A&M University, 2009; B.S., Mathematics, Northwestern State University, 1999. Joe joined NSAI in 2013 after working for Pioneer Natural Resources and Sovereign Resources, LLC. His work includes oil and gas reserves estimation and auditing, volumetric analyses, and economic evaluations for international and domestic oil and gas projects. Joe has served in various expert capacities including independent joint expert and expert witness. He is a licensed Professional Engineer in the State of Texas, a Registered Professional Engineer in Queensland (RPEQ) in Australia, and a member of the Society of Petroleum Engineers (SPE).
Melanie D. Ybarra
Petrophysical Specialist
Petrophysics • Dallas
M.S. in Geology, University of Texas at Arlington, 2014; B.S. in Mathematics, University of Houston, 2005. Melanie has been with NSAI since 2005. She has extensive experience in formation evaluation of both unconventional and conventional reservoirs around the world. She provides advanced petrophysical support and geological mapping for reserves and resource evaluations, major field studies, and reservoir simulation studies. She is a licensed Professional Geologist in the state of Texas and a member of Society of Petroleum and Well Log Analysts (SPWLA).
Analyst Coordinators
Our staff of petroleum analysts are integral to each evaluation, working closely with the engineers and geoscientists and with our clients. They generally have 3 to 15 years experience and have degrees in mathematics, computer science, geology, or business. They have diverse skills in data loading, database management, economic modeling, spreadsheet manipulation, computer mapping, well log processing, and report preparation.
Amy H. Arnold
Dallas • Contact Info
Jake S. Bontrager
Dallas • Contact info
Diana E. Castillo
Houston • Contact info
Levi E. Enslow
Dallas • Contact info
Lisa R. Green
Houston • Contact info
Maddie B. Gulick
Dallas • Contact info
Natalie F. Hudson
Houston • Contact info
Rachel K. Lowrance
Dallas • Contact info
Shannon R. Mapes
Houston • Contact info
Heather R. Maresh
Houston • Contact info
Jeremiah B. Scott
Dallas • Contact info
Ram Shoham
Houston • Contact info
Dawn S. Smith
Dallas • Contact info
Michael S. Strohmann
Houston • Contact info
Julie C. Wilburn
Dallas • Contact info