GeothermEx Senior Staff — a Wealth of Geothermal Expertise
Dr. Subir K. Sanyal
President and Manager of Reservoir Engineering Services
Subir, who joined GeothermEx in 1980, has been a leader in the geothermal industry for decades. His knowledge and expertise in the areas of geothermal project financing, management, economic analysis, property appraisal, reservoir engineering, numerical simulation, training and software development is unmatched. He is widely sought after as an expert witness and for his skills in due diligence projects. For the past three decades, Subir has managed major geothermal projects in the United States, the Philippines, Japan, Costa Rica, Indonesia, Mexico, Nicaragua, Guatemala and Italy. He has conducted technology transfer and evaluated geothermal fields in more than two dozen countries. In addition, Subir has assisted clients in sales negotiations, property appraisals, market studies and economic analysis.
Subir has a Ph.D. in Petroleum Engineering from Stanford University and a Master’s degree in Petroleum Engineering from the University of Birmingham (England.) He serves on the board of the Geothermal Resources Council and the Geothermal Energy Association in the United States as well as the International Geothermal Association. Subir is the author or co-author of more than 100 technical publications. He speaks and reads Spanish and can read Russian.
Subir Sanyal’s complete CV (PDF) 
Eduardo E. Granados
Senior Vice President, Drilling Services
Eduardo, who joined GeothermEx in 1984, is a renowned expert in geothermal exploration, drilling and well testing. Eduardo has worked on all aspects of geothermal well drilling, well control, testing, data analysis and the construction of surface facilities in numerous geothermal fields around the world. He has taught many courses on drilling and well testing throughout the Western Hemisphere. Eduardo also has significant expertise in regulatory issues and has participated in devising appropriate regulations to govern geothermal development in several countries.
Eduardo has a Master’s degree in Petroleum Engineering from Stanford University and a Bachelor’s degree in Civil Engineering from the University of Costa Rica. He speaks, reads and writes Spanish and speaks and reads French and Italian.
Eduardo Granados’ complete CV (PDF)
Roger C. Henneberger
Vice President, Earth Sciences
Roger, who has been with GeothermEx since 1984, has expertise in all phases of geothermal exploration, development, management and finance. He has managed and coordinated comprehensive assessments of geothermal resources in dozens of fields, and led several nation-wide assessments of resources in countries such as Nicaragua and India. He has designed and implemented geothermal exploration programs in the U.S. and elsewhere, managed exploration and the development of drilling programs, and performed wellsite geology, technical monitoring of drilling operations, testing and geochemical sampling at more than 30 sites in 14 countries. Roger also develops financial models and analyzes specific economic aspects (such as tax benefits) of existing and proposed geothermal operations.
Roger was awarded a Fulbright Scholarship to study geothermal energy in New Zealand and received a MSc degree in Geology with First Class Honours in 1983. He also has a B.S. in Geology from Stanford University (1978). He communicates fluently in Spanish and can read and speak Portuguese.
Roger Henneberger’s complete CV (PDF)
James W. Lovekin
Vice President, Field Operations
Jim’s expertise spans all aspects of geothermal operations. He has been responsible for planning field development and monitoring reservoir performance at numerous major geothermal fields in the United States, Indonesia and Central America. In addition, he has significant experience in testing and evaluating production wells, reservoir monitoring, forecasting reservoir performance and budgeting and cost control for drilling and monitoring processes.
Jim has an Engineer’s degree in Petroleum Engineering from Stanford University, a Bachelor’s degree in Geological Engineering from the University of Nevada, and a Bachelor’s degree in American Studies from Amherst College. Jim is a board member of the Geothermal Resources Council. He is fluent in French, can speak and read Spanish, and reads Russian.
Jim Lovekin’s complete CV (PDF)
Ann Robertson-Tait
Vice President, Business Development / Senior Geologist
Ann specializes in the integration of geological, geochemical, and geophysical data to develop conceptual models for geothermal energy reserves, an expertise she has brought to more than 30 geothermal fields around the world. In addition, Ann specializes in the evaluation and development of Enhanced Geothermal Systems (EGS), both within and around existing geothermal project areas, and greenfield EGS developments. She has provided national leadership in the EGS arena, managing major R&D activities for projects funded by the US Department of Energy, promoting EGS technology to US geothermal operators, and developing a portfolio of potential EGS projects adjacent to or within developed hydrothermal fields.
Ann was awarded a Fulbright Scholarship to study geothermal energy in New Zealand and received an MSc degree in Geology from the University of Auckland in 1984. She received her B.S. degree in Geology from Florida Atlantic University in 1981.
Ann Robertson-Tait’s complete CV (PDF)
Dr. Christopher W. Klein
Senior Geochemist
Chris has been with GeothermEx since 1974 and is an expert in geochemistry, geology and hydrologic modeling as well as interpretation of downhole, chemical and integrated reservoir engineering data. He has worked on geothermal geochemistry in nearly every country in the world that has active geothermal resources. This work includes project design, fluid chemistry sampling and analysis, field lab design, field personnel training, monitoring and modeling. Chris also has significant expertise in geochemical software design, management and training.
Chris has a Ph.D. in Geology from Harvard University and a Bachelor’s degree in chemistry from the University of California, Berkeley. He speaks, reads and writes Spanish.
Chris Klein’s complete CV (PDF)
Steven J. Butler
Senior Reservoir Engineer
Steve has been with GeothermEx since 1997. His expertise includes numerical reservoir simulation, two-phase pipeline and wellbore modeling, reserve estimation, production engineering, and scale control. His experience also includes process engineering and surface facilities. Steve has been involved in the design, construction, start-up, operation and overhaul of several geothermal power plants and has worked extensively on mineral recovery from geothermal brines.
Steve has a Master’s degree in Petroleum Engineering from the University of Southern California and a Bachelor’s degree in Chemical Engineering from California Polytechnic Institute, and a second Bachelor’s degree in Chemistry from California State University, Fullerton.
Steve Butler’s complete CV (PDF)
Minh Pham
Senior Reservoir Engineer
Minh is a specialist in numerical simulation in porous media. His expertise includes analysis of two-phase flow, wellbore simulation, numerical simulation of geothermal reservoirs and developing numerical simulation software. He has worked on numerous reservoir numerical simulation projects and conducted numerical simulation training programs in the United States, Japan and Central America.
Minh has a Master’s degree in Mechanical Engineering from San Jose State University and a Bachelor’s degree in Petroleum Engineering from the University of California, Berkeley.
Minh Pham’s complete CV (PDF)
Senior Advisors
Jim Koenig, the founder and President of GeothermEx from 1973 to 1995, has been active in geothermal exploration, drilling and field development since 1965, when he pioneered legislation governing geothermal resources in California and at the national level in the US. He has managed geothermal exploration and development projects in Kenya, Costa Rica, the Philippines, Papua New Guinea, Honduras, Nicaragua, Indonesia, and the United States. He has generously served multiple terms as a Director of both the Geothermal Resources Council and the International Geothermal Association, and has been instrumental in organizing all three World Geothermal Congresses that have been held to date. Since his retirement in 1995, Jim continues to serve as a willing geothermal ambassador to many nations.
Jim Koenig’s complete CV (PDF)
Jim McNitt has been a leader in geothermal exploration and development since 1959. His expertise ranges from exploration, evaluation and testing through modeling and management. Over his long career, Jim has worked in 31 countries and sited successful discovery and step-out wells in numerous geothermal fields. Jim has served as a technical advisor for the United Nations and published the first detailed geologic map of The Geysers field in California, the largest known single geothermal field in the world. Since his retirement in 1997, Jim continues to work on projects of interest, including many at the early exploration phase.
Jim has a Ph.D. in Geology from the University of California, Berkeley, a Master’s degree in Geology from the University of Illinois, and a Bachelor’s degree in Geology from Notre Dame University.
Jim McNitt’s complete CV (PDF)
