Geoffrey S Ellis
Geoffrey Ellis is a petroleum geochemist with the Energy Resources Program (ERP) of the US Geological Survey. He manages the sealed tube and hydrous pyrolysis laboratories within the Central Energy Resources Science Center.
Geoffrey Ellis' research interests encompass the areas of organic-inorganic interactions in petroleum systems, gas isotope geochemistry, and the controls on sedimentary organic geochemistry in aquatic environments. He has published extensively on the process of thermochemical sulfate reduction and its impact on petroleum geochemistry. He is also actively investigating the application of compound-specific sulfur isotope analysis to problems in petroleum and organic geochemistry. He also has ongoing research projects involving clumped and position specific isotope analysis of hydrocarbons and organosulfur compounds and their relation to petroleum formation processes.
Professional Experience
2006-Present: Research Geologist, Energy Resources Program, USGS
2003-2006: Postdoctoral Fellow, Division of Chemistry & Chemical Engineering, California Institute of Technology
1996-2003: Graduate Research Assistant, Rosenstiel School of Marine and Atmospheric Science, University of Miami
1994-1996: Consulting Petroleum Geochemist, Venezuela
1991-1994: Physical Scientist, Nation Research Program, Water Resources Division, USGS
1988-1990: Geochemist, Northeast Research Institute
Education and Certifications
Ph.D., Marine Geology and Geophysics, Rosenstiel School of Marine and Atmospheric Science, University of Miami
M.S., Geochemistry, Colorado School of Mines
B.A., Geological Sciences, Cornell University
Affiliations and Memberships*
Affiliate faculty Department of Geology and Geological Engineering, Colorado School of Mines
Member American Association of Petroleum Geologists, European Association of Organic Geochemists, Geochemical Society, Geological Society of America
Member Association of Afro-Asian Petroleum Geochemists, Latin American Association of Organic Geochemistry
Member of the “Committee on Research” of the American Association of Petroleum Geologists (2009-present)
Vice-chairman of the executive council of the Association of Afro-Asian Petroleum Geochemists
Founding member of the editorial board of the journal Petroleum Research
Member of the editorial board of the English-language version of the journal Acta Petrolei Sinica
Member of the editorial board of the journal Journal of Natural Gas Geoscience
Member of the editorial board of the journal Unconventional Resources
Science and Products
Late Quaternary stratigraphy, sedimentology, and geochemistry of an underfilled lake basin in the Puna (north-west Argentina)
Effect of organic matter properties, clay mineral type and thermal maturity on gas adsorption in organic-rich shale systems
Lacustrine records of Holocene flood pulse dynamics in the Upper Paraguay River watershed (Pantanal wetlands, Brazil)
Playa-lake sedimentation and organic matter accumulation in an Andean piggyback basin: The recent record from the Cuenca de Pozuelos, NW Argentina
Effect of organic-matter type and thermal maturity on methane adsorption in shale-gas systems
Kinetics of uncatalyzed thermochemical sulfate reduction by sulfur-free paraffin
Limnogeology in Brazil's "forgotten wilderness": A synthesis from the large floodplain lakes of the Pantanal
Assessment of undiscovered oil and gas resources of the Anadarko Basin Province of Oklahoma, Kansas, Texas, and Colorado, 2010
Fundamental studies on kinetic isotope effect (KIE) of hydrogen isotope fractionation in natural gas systems
Assessment of undiscovered natural gas resources of the Arkoma Basin province and geologically related areas
Gas storage in the Upper Devonian-Lower Mississippian Woodford Shale, Arbuckle Mountains, Oklahoma: how much of a role do the cherts play?
Experimental investigation on thermochemical sulfate reduction by H2S initiation
Science and Products
- Data
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Filter Total Items: 67
Late Quaternary stratigraphy, sedimentology, and geochemistry of an underfilled lake basin in the Puna (north-west Argentina)
Depositional models of ancient lakes in thin-skinned retroarc foreland basins rarely benefit from appropriate Quaternary analogues. To address this, we present new stratigraphic, sedimentological and geochemical analyses of four radiocarbon-dated sediment cores from the Pozuelos Basin (PB; northwest Argentina) that capture the evolution of this low-accommodation Puna basin over the past ca. 43 calAuthorsMichael M. McGlue, Andrew S. Cohen, Geoffrey S. Ellis, Andrew L. KowlerEffect of organic matter properties, clay mineral type and thermal maturity on gas adsorption in organic-rich shale systems
A series of CH4 adsorption experiments on natural organic-rich shales, isolated kerogen, clay-rich rocks, and artificially matured Woodford Shale samples were conducted under dry conditions. Our results indicate that physisorption is a dominant process for CH4 sorption, both on organic-rich shales and clay minerals. The Brunauer–Emmett–Teller (BET) surface area of the investigated samples is lineaAuthorsTongwei Zhang, Geoffrey S. Ellis, Stephen C. Ruppel, Kitty Milliken, Mike Lewan, Xun SunLacustrine records of Holocene flood pulse dynamics in the Upper Paraguay River watershed (Pantanal wetlands, Brazil)
The Pantanal is the world's largest tropical wetland and a biodiversity hotspot, yet its response to Quaternary environmental change is unclear. To address this problem, sediment cores from shallow lakes connected to the UpperParaguayRiver (PR) were analyzed and radiocarbon dated to track changes in sedimentary environments. Stratal relations, detrital particle size, multiple biogeochemical indicaAuthorsMichael M. McGlue, Aquinaldo Silva, Hiran Zani, Fabricio A. Corradini, Mauro Parolin, Erin J. Abel, Andrew S. Cohen, Mario L. Assine, Geoffrey S. Ellis, Mark A. Trees, Sidney Kuerten, Frederico dos Santos Gradella, Giliane Gessica RasboldPlaya-lake sedimentation and organic matter accumulation in an Andean piggyback basin: The recent record from the Cuenca de Pozuelos, NW Argentina
Expansive playa‐lake systems situated in high‐altitude piggyback basins are important and conspicuous components of both modern and ancient cordilleran orogenic systems. Extant playa lakes provide vital habitat for numerous endemic species, whereas sediments from these deposystems may record signals of climate change or develop natural resources over geological time. Laguna de los Pozuelos (North‐AuthorsMichael M. McGlue, Geoffrey S Ellis, Andrew S. Cohen, Peter W SwarzenskiEffect of organic-matter type and thermal maturity on methane adsorption in shale-gas systems
A series of methane (CH4) adsorption experiments on bulk organic rich shales and their isolated kerogens were conducted at 35 °C, 50 °C and 65 °C and CH4 pressure of up to 15 MPa under dry conditions. Samples from the Eocene Green River Formation, Devonian–Mississippian Woodford Shale and Upper Cretaceous Cameo coal were studied to examine how differences in organic matter type affect natural gasAuthorsTongwei Zhang, Geoffrey S. Ellis, Stephen C. Ruppel, Kitty Milliken, Rongsheng YangKinetics of uncatalyzed thermochemical sulfate reduction by sulfur-free paraffin
To determine kinetic parameters of sulfate reduction by hydrocarbons (HC) without the initial presence of low valence sulfur, we carried out a series of isothermal gold-tube hydrous-pyrolysis experiments at 320, 340, and 360 °C under a constant confined pressure of 24.1 MPa. The reactants used consisted of saturated HC (sulfur-free) and CaSO4 in an aqueous solution buffered to three different pH cAuthorsTongwei Zhang, Geoffrey S. Ellis, Qisheng Ma, Alon Amrani, Yongchun TangLimnogeology in Brazil's "forgotten wilderness": A synthesis from the large floodplain lakes of the Pantanal
Sediment records from floodplain lakes have a large and commonly untapped potential for inferring wetland response to global change. The Brazilian Pantanal is a vast, seasonally inundated savanna floodplain system controlled by the flood pulse of the Upper Paraguay River. Little is known, however, about how floodplain lakes within the Pantanal act as sedimentary basins, or what influence hydroclimAuthorsMichael M. McGlue, Aguinaldo Silva, Fabricio A. Corradini, Hiran Zani, Mark A. Trees, Geoffrey S. Ellis, Mauro Parolin, Peter W. Swarzenski, Andrew S. Cohen, Mario L. AssineAssessment of undiscovered oil and gas resources of the Anadarko Basin Province of Oklahoma, Kansas, Texas, and Colorado, 2010
The U.S. Geological Survey, using a geoscience-based assessment methodology, estimated mean technically-recoverable undiscovered continuous and conventional resources that total 495 million barrels of oil, 27.5 trillion cubic feet of natural gas, and 410 million barrels of natural gas liquids in the Anadarko Basin Province; this assessment includes the Las Animas arch area of southeastern ColoradoAuthorsD. K. Higley, S.B. Gaswirth, M.M. Abbott, Ronald R. Charpentier, T. A. Cook, G.S. Ellis, N.J. Gianoutsos, J. R. Hatch, T. R. Klett, Philip H. Nelson, M. J. Pawlewicz, O.N. Pearson, R. M. Pollastro, Christopher J. SchenkFundamental studies on kinetic isotope effect (KIE) of hydrogen isotope fractionation in natural gas systems
Based on quantum chemistry calculations for normal octane homolytic cracking, a kinetic hydrogen isotope fractionation model for methane, ethane, and propane formation is proposed. The activation energy differences between D-substitute and non-substituted methane, ethane, and propane are 318.6, 281.7, and 280.2 cal/mol, respectively. In order to determine the effect of the entropy contribution forAuthorsY. Ni, Q. Ma, G.S. Ellis, J. Dai, Brian Katz, S. Zhang, Y. TangAssessment of undiscovered natural gas resources of the Arkoma Basin province and geologically related areas
Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean volumes of 38 trillion cubic feet (TCF) of undiscovered natural gas, 159 million barrels of natural gas liquid (MMBNGL), and no oil in accumulations of 0.5 million barrels (MMBO) or larger in the Arkoma Basin Province and related areas. More than 97 percent of the undiscovered gas occurs in continuous accumulatAuthorsDavid W. Houseknecht, James L. Coleman, Robert C. Milici, Christopher P. Garrity, William A. Rouse, Bryant R. Fulk, Stanley T. Paxton, Marvin M. Abbott, John L. Mars, Troy A. Cook, Christopher J. Schenk, Ronald R. Charpentier, Timothy R. Klett, Richard M. Pollastro, Geoffrey S. EllisGas storage in the Upper Devonian-Lower Mississippian Woodford Shale, Arbuckle Mountains, Oklahoma: how much of a role do the cherts play?
How gas is stored in shale-gas systems is a critical element in characterizing these potentially prolific, low-porosity/permeability reservoirs. An integrated mineralogic, geochemical, and porosity/permeability study is of the Upper Devonian-Lower Mississippian Woodford Shale, Arbuckle Mountains, southern Oklahoma, at locations previously described through detailed stratigraphic and spectral gammaAuthorsNeil S. Fishman, Geoffrey S. Ellis, Stanley T. Paxton, Marvin M. Abbott, Adam BoehlkeExperimental investigation on thermochemical sulfate reduction by H2S initiation
Hydrogen sulfide (H2S) is known to catalyze thermochemical sulfate reduction (TSR) by hydrocarbons (HC), but the reaction mechanism remains unclear. To understand the mechanism of this catalytic reaction, a series of isothermal gold-tube hydrous pyrolysis experiments were conducted at 330 °C for 24 h under a constant confining pressure of 24.1 MPa. The reactants used were saturated HC (sulfur-freeAuthorsTongwei Zhang, Alon Amrani, Geoffrey S Ellis, Qisheng Ma, Yongchun Tang, David Applegate - News
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