Brett J. Valentine
Brett Valentine is a Physical Scientist with the USGS Geology, Energy & Minerals (GEM) Science Center in Reston, VA.
Since joining the USGS in 2009, Brett has devoted his career to studying organic petrology and specializes in electron microscopy techniques. He is currently the manager of the Reston Electron Microbeam Laboratory at USGS National Center in Reston, VA. Presently, his research focuses on developing electron microscopy methods and applications to improve our understanding of the micro-to-nanoscale changes that occur to coals and organic-rich shales as they thermally mature.
Professional Experience
Physical Scientist, USGS Geology, Energy & Minerals Science Center, 2009-Present
Assistant County Soil Scientist, Fauquier County, VA, 2004-2009
Education and Certifications
B.S. Forestry and Environmental Science, Virginia Tech
Science and Products
High Microscale Variability in Raman Thermal Maturity Estimates from Shale Organic Matter - Data Release
Petroleum geology data from Mesozoic rock samples in the eastern U.S. Gulf Coast collected 2011 to 2017
Characterization of the unconventional Tuscaloosa marine shale reservoir in southwestern Mississippi, USA: Insights from optical and SEM petrography
Applications of correlative light and electron microscopy (CLEM) to organic matter in the North American shale petroleum systems
Testing reproducibility of vitrinite and solid bitumen reflectance measurements in North American unconventional source-rock reservoir petroleum systems
Organic petrography of Leonardian (Wolfcamp A) mudrocks and carbonates, Midland Basin, Texas: The fate of oil-prone sedimentary organic matter in the oil window
Application of electron microscopy TEM and SEM for analysis of coals, organic-rich shales and carbonaceous matter
Reflectance increase from broad beam ion milling of coals and organic-rich shales due to increased surface flatness
High microscale variability in Raman thermal maturity estimates from shale organic matter
Assessment of undiscovered continuous oil and gas resources in the Upper Cretaceous Tuscaloosa marine shale of the U.S. Gulf Coast, 2018
On the petrographic distinction of bituminite from solid bitumen in immature to early mature source rocks
Geologic characterization of the hydrocarbon resource potential of the Upper Cretaceous Tuscaloosa marine shale in Mississippi and Louisiana, U.S.A.
Utilization of integrated correlative light and electron microscopy (iCLEM) for imaging sedimentary organic matter
Geologic assessment of undiscovered oil and gas resources—Lower Cretaceous Albian to Upper Cretaceous Cenomanian carbonate rocks of the Fredericksburg and Washita Groups, United States Gulf of Mexico Coastal Plain and State Waters
Science and Products
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High Microscale Variability in Raman Thermal Maturity Estimates from Shale Organic Matter - Data Release
Here the spatial variation in Raman estimates of thermal maturity within individual organic domains from several shale geologic reference materials originating from the Boquillas, Marcellus, Niobrara, and Woodford Formations are assessed from the respective Raman response. We show that for all four shales the thermal maturity parameters extracted from Raman spectra by iterative peak fitting can vaPetroleum geology data from Mesozoic rock samples in the eastern U.S. Gulf Coast collected 2011 to 2017
This data release contains Rock-Eval pyrolysis, organic petrographic (reflectance), and X-ray diffraction mineralogy data for subsurface Mesozoic rock samples from the eastern onshore Gulf Coast Basin (primarily Mississippi and Louisiana). Samples were analyzed in support of the U.S. Geological Survey (USGS) assessment of undiscovered petroleum resources in the Upper Cretaceous Tuscaloosa marine s - Multimedia
- Publications
Filter Total Items: 52
Characterization of the unconventional Tuscaloosa marine shale reservoir in southwestern Mississippi, USA: Insights from optical and SEM petrography
This study presents new optical petrography and electron microscopy data, interpreted in the context of previously published petrophysical, geochemical, and mineralogical data, to further characterize the Tuscaloosa marine shale (TMS) as an unconventional reservoir in southwestern Mississippi. The basal high resistivity zone has a higher proportion of Type II sedimentary organic matter than the ovAuthorsCeleste D. Lohr, Brett J. Valentine, Paul C. Hackley, Frank T. DulongApplications of correlative light and electron microscopy (CLEM) to organic matter in the North American shale petroleum systems
Scanning electron microscopy (SEM) has revolutionized our understanding of shale petroleum systems through microstructural characterization of dispersed organic matter (OM). However, due to the low atomic weight of carbon, all OM appears black in SEM (BSE image) regardless of differences in thermal maturity or OM type (kerogen types or solid bitumen). Traditional petrographic identification of OMAuthorsBrett J. Valentine, Paul C. HackleyTesting reproducibility of vitrinite and solid bitumen reflectance measurements in North American unconventional source-rock reservoir petroleum systems
An interlaboratory study (ILS) was conducted to test reproducibility of vitrinite and solid bitumen reflectance measurements in six mudrock samples from United States unconventional source-rock reservoir petroleum systems. Samples selected from the Marcellus, Haynesville, Eagle Ford, Barnett, Bakken and Woodford are representative of resource plays currently under exploitation in North America. AlAuthorsPaul C. Hackley, Carla V. Araujo, Angeles G. Borrego, Antonis Bouzinos, Brian J. Cardott, H. Carvajal-Ortiz, Martha Rocio Lopez Cely, Vongani Chabalala, Peter J. Crosdale, Thomas D. Demchuk, Cortland F. Eble, Deolinda Flores, Agnieszka Furmann, Thomas Gentzis, Paula Goncalves, Carsten Guvad, M. Hamor-Vido, Iwona Jelonek, M. Johnston, Tatiana Juliao-Lemus, Stavros Kalaitzidis, Wayne Knowles, Jolanta Kus, Zhongsheng Li, Gordon Macleod, Maria Mastalerz, Taissa Rego Menezes, Seare Ocubalidet, Richard Orban, Walter Pickel, Paddy Ranasinghe, Joana Ribeiro, Olga Patricia Gomez Rojas, Ricardo Ruiz-Monroy, Jaques Schmidt, Abbas Seyedolali, Georgios Siavalas, Isabel Suarez-Ruiz, Carlos Vargas Vargas, Brett J. Valentine, Nicola Wagner, Bree Wrolson, Julian Esteban Jaramillo ZapataOrganic petrography of Leonardian (Wolfcamp A) mudrocks and carbonates, Midland Basin, Texas: The fate of oil-prone sedimentary organic matter in the oil window
To better understand evolution of oil-prone sedimentary organic matter to petroleum and expulsion from source rock, we evaluated organic petrographic features of Leonardian Wolfcamp A repetitive siliceous and calcareous mudrock and fine-grained carbonate lithofacies cycles occurring in the R. Ricker #1 core from Reagan County, Midland Basin, Texas. The objectives of the petrographic investigationAuthorsPaul C. Hackley, Tongwei Zhang, Aaron M. Jubb, Brett J. Valentine, Frank T. Dulong, Javin J. HatcherianApplication of electron microscopy TEM and SEM for analysis of coals, organic-rich shales and carbonaceous matter
This paper provides a brief summary of the history, development and variety of applications of electron microscopy techniques to analyze coals, organic-rich shales, and carbonaceous materials. General construction and principles of operation of transmitted (TEM) and scanning electron microscope (SEM) are outlined, along with guidance on specimen preparation, and a brief overview of published TEM aAuthorsB. Kwiecińska, Brett J. Valentine, S. PuszReflectance increase from broad beam ion milling of coals and organic-rich shales due to increased surface flatness
Broad ion beam (BIB) milling is useful in organic petrology because it can yield flat sample surfaces and avert the ‘smearing’ of organic matter (OM) that results from traditional mechanical polishing. This potentially makes BIB especially useful in the study of nano-porosity, where even minor mechanical disruption of the sample surface distorts the sample characteristic of interest—the pore struAuthorsBrett J. Valentine, Paul C. Hackley, Javin J. Hatcherian, Jing-Jiang YuHigh microscale variability in Raman thermal maturity estimates from shale organic matter
Raman spectroscopy has recently received attention as a means to estimate thermal maturity of organic matter in petroleum generating source rocks to complement more traditional approaches such as vitrinite reflectance and programmed pyrolysis. While many studies have observed positive correlations between source rock thermal maturity and Raman spectral parameters, little attention has been given tAuthorsAaron M. Jubb, Palma J. Botterell, Justin E. Birdwell, Robert C. Burruss, Paul C. Hackley, Brett J. Valentine, Javin J. Hatcherian, Stephen A. WilsonAssessment of undiscovered continuous oil and gas resources in the Upper Cretaceous Tuscaloosa marine shale of the U.S. Gulf Coast, 2018
Using a geology-based assessment methodology, the U.S. Geological Survey assessed mean undiscovered, technically recoverable continuousresources of 1.5 billion barrels of oil and 4.6 trillion cubic feet of gas in the Upper Cretaceous Tuscaloosa marine shale in onshore and State waters ofLouisiana, Mississippi, Alabama, and Florida in the U.S. Gulf Coast region.AuthorsPaul C. Hackley, Catherine B. Enomoto, Brett J. Valentine, William A. Rouse, Celeste D. Lohr, Frank T. Dulong, Javin J. Hatcherian, Sean T. Brennan, William H. Craddock, Thomas M. Finn, Stephanie B. Gaswirth, Phuong A. Le, Heidi M. Leathers-Miller, Kristen R. Marra, Tracey J. Mercier, Stanley T. Paxton, Katherine J. Whidden, Cheryl A. Woodall, Christopher J. SchenkOn the petrographic distinction of bituminite from solid bitumen in immature to early mature source rocks
The oil-prone maceral bituminite (and its equivalents: ‘amorphous organic matter’, ‘sapropelinite’, ‘amorphinite’, etc.) converts to petroleum during thermal maturation of source rocks, resulting in formation of a mobile saturate-rich hydrocarbon and a polar-rich residue of solid bitumen. Evidence of this transition is preserved in immature to early mature source rocks (e.g., Alum, Bakken, KimmeriAuthorsPaul C. Hackley, Brett J. Valentine, Javin J. HatcherianGeologic characterization of the hydrocarbon resource potential of the Upper Cretaceous Tuscaloosa marine shale in Mississippi and Louisiana, U.S.A.
Recent oil production from the Upper Cretaceous Tuscaloosa marine shale (TMS) has elevated the formation, previously assessed by the USGS in 2011 as part of the Eagle Ford Group, to its own distinct assessment unit for an upcoming assessment. Geologic characterization in preparation for the 2017 assessment has included the analysis of rock samples and produced oils, and the interpretation of wellAuthorsCatherine B. Enomoto, Paul C. Hackley, Brett J. Valentine, William A. Rouse, Frank T. Dulong, Celeste D. Lohr, Javin J. HatcherianUtilization of integrated correlative light and electron microscopy (iCLEM) for imaging sedimentary organic matter
We report here a new microscopic technique for imaging and identifying sedimentary organic matter in geologic materials that combines inverted fluorescence microscopy with scanning electron microscopy and allows for sequential imaging of the same region of interest without transferring the sample between instruments. This integrated correlative light and electron microscopy technique is demonstratAuthorsPaul C. Hackley, Brett J. Valentine, Leonard M. Voortman, Daan van Oosten Slingeland, Javin J. HatcherianGeologic assessment of undiscovered oil and gas resources—Lower Cretaceous Albian to Upper Cretaceous Cenomanian carbonate rocks of the Fredericksburg and Washita Groups, United States Gulf of Mexico Coastal Plain and State Waters
In 2010, the U.S. Geological Survey (USGS) assessed Lower Cretaceous Albian to Upper Cretaceous Cenomanian carbonate rocks of the Fredericksburg and Washita Groups and their equivalent units for technically recoverable, undiscovered hydrocarbon resources underlying onshore lands and State Waters of the Gulf Coast region of the United States. This assessment was based on a geologic model that incorAuthorsSharon M. Swanson, Catherine B. Enomoto, Kristin O. Dennen, Brett J. Valentine, Steven M. Cahan - Web Tools