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Paul C Hackley, Ph.D.

Paul Hackley is a Research Geologist with the USGS Geology, Energy & Minerals (GEM) Science Center in Reston, VA.

As project chief of the Thermal Indices project I pursue research on thermal maturity, chemical composition and physical state of sedimentary organic matter. The Thermal Indices project is part of the Geology, Energy & Minerals (GEM) Science Center and is funded by the Energy Resources Program (ERP). The Thermal Indices project team develops and applies petrographic methods for the reliable identification of different types of sedimentary organic matter, and measures and interprets the response of organic matter to thermal stress in natural environments and in laboratory-based heating experiments. Improved understanding of the thermal evolution of sedimentary organic matter enables more accurate assessment of petroleum source rock maturation, thereby decreasing uncertainty in the determination of thermal histories, the timing of petroleum generation and the placement of resource assessment spatial boundaries. This leads to the overall goal of improving estimates of undiscovered petroleum resources, which is a central mission of the ERP. 

My work focuses on four integrated research task areas which have petrographic approaches to thermal indices as their common denominator: 1) standardization and reproducibility of measurement, 2) utilization of hydrous pyrolysis for (artificial) thermal conversion of sedimentary organic matter, 3) petrographic innovation areas for thermal indices and organic evolution, and 4) petrographic laboratory support. 

Thermal indices research is accomplished from the Organic Petrology and Hydrous Pyrolysis laboratories in Reston. The laboratories include facilities for sample preparation, hydrous pyrolysis, optical and fluorescence microscopy, and infrared spectroscopy. The Thermal Indices project team works with external collaborators from global academic, government and industry groups. All thermal indices research efforts reach toward the goal of improving fossil fuel resource assessments by generating new understanding of the processes occurring during thermal evolution of sedimentary organic matter and its conversion to petroleum. 

Education

  • Ph.D., George Mason University
  • M.S., George Washington University
  • B.A., Shippensburg State University

Work Experience

  • Unconventional petroleum systems
  • Conventional oil and gas assessment
  • Coalbed methane
  • Coal
  • Application of organic petrology techniques to fossil fuel resource assessment

Professional Affiliations

  • The Society for Organic Petrology (TSOP)
  • International Committee for Coal and Organic Petrology (ICCP)
  • American Association of Petroleum Geologists (AAPG)
  • American Society for Testing and Materials (ASTM)
  • Geological Society of America (GSA)

Science and Products

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Photomicrograph Atlas thumb

Photomicrograph Atlas

The Photomicrograph Atlas provides a basic tutorial in the nomenclature of organic materials as they occur in sedimentary rocks such as coal and shale, information on the taxonomies used by various groups and organizations, and a database of images related to the characterization of fossil fuel resources in the United States and the world.
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Geology, Energy & Minerals Science Center
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Photomicrograph Atlas

The Photomicrograph Atlas provides a basic tutorial in the nomenclature of organic materials as they occur in sedimentary rocks such as coal and shale, information on the taxonomies used by various groups and organizations, and a database of images related to the characterization of fossil fuel resources in the United States and the world.
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Vitrinite Reflectance Service Thumb

Vitrinite Reflectance Service

Vitrinite reflectance is regarded as the gold standard thermal maturity parameter and vitrinite reflectance data is needed for energy resource assessment and other types of basin analysis studies. This effort provides vitrinite reflectance and qualitative organic petrography of shale, mudrock, coal and other unconventional reservoir samples as a routine in-house service, from the Organic Petrology...
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Energy Resources Program, Geology, Energy & Minerals Science Center
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Vitrinite Reflectance Service

Vitrinite reflectance is regarded as the gold standard thermal maturity parameter and vitrinite reflectance data is needed for energy resource assessment and other types of basin analysis studies. This effort provides vitrinite reflectance and qualitative organic petrography of shale, mudrock, coal and other unconventional reservoir samples as a routine in-house service, from the Organic Petrology...
Learn More
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Thermal Indices Innovation Thumb

Thermal Indices Innovation

Thermal indices innovation utilizes correlative microscopy techniques for innovative approaches to thermal indices development, including confocal laser scanning microscopy (CLSM), AFM-IR (combined atomic force and infrared microscopy), atomic force microscopy (AFM), and SEM of Argon ion-milled sample surfaces combined with traditional organic petrography. The innovation task also is testing...
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Energy Resources Program, Geology, Energy & Minerals Science Center
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Thermal Indices Innovation

Thermal indices innovation utilizes correlative microscopy techniques for innovative approaches to thermal indices development, including confocal laser scanning microscopy (CLSM), AFM-IR (combined atomic force and infrared microscopy), atomic force microscopy (AFM), and SEM of Argon ion-milled sample surfaces combined with traditional organic petrography. The innovation task also is testing...
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Hydrous Pyrolysis Kerogen Thumb

Hydrous Pyrolysis and Kerogen Conversion

This work is directed at understanding the kinetics of vitrinite and solid bitumen maturation through hydrous pyrolysis experiments, potentially enabling a direct methodology to detect ‘vitrinite reflectance suppression,’ a commonly reported problem in the early- to mid-oil window. This task also examines the molecular chemistry of kerogen conversion to petroleum via in situ chemical probing by...
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Energy Resources Program, Geology, Energy & Minerals Science Center
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Hydrous Pyrolysis and Kerogen Conversion

This work is directed at understanding the kinetics of vitrinite and solid bitumen maturation through hydrous pyrolysis experiments, potentially enabling a direct methodology to detect ‘vitrinite reflectance suppression,’ a commonly reported problem in the early- to mid-oil window. This task also examines the molecular chemistry of kerogen conversion to petroleum via in situ chemical probing by...
Learn More
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Standardization Thumb

Standardization of Petrographic Measurements

Advent of the ‘shale revolution’ since about 2005 has caused increased demand for reliable petrographic measurements of thermal maturity in shale via vitrinite reflectance, long considered the ‘gold standard’ approach. A standardized methodology for organic reflectance measurement in shale first became available in 2011 (ASTM D7708), based on prior work by task members. However, interlaboratory...
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Energy Resources Program, Geology, Energy & Minerals Science Center
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Standardization of Petrographic Measurements

Advent of the ‘shale revolution’ since about 2005 has caused increased demand for reliable petrographic measurements of thermal maturity in shale via vitrinite reflectance, long considered the ‘gold standard’ approach. A standardized methodology for organic reflectance measurement in shale first became available in 2011 (ASTM D7708), based on prior work by task members. However, interlaboratory...
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Photoluminescence Imaging of Whole Zircon Grains on a Petrographic Microscope - An Underused Aide for Geochronologic Studies

The refractory nature of zircon to temperature and pressure allows even a single zircon grain to preserve a rich history of magmatic, metamorphic, and hydrothermal processes. Isotopic dating of micro-domains exposed in cross-sections of zircon grains allows us to interrogate this history. Unfortunately, our ability to select the zircon grains in a heavy mineral concentrate that records the most ge
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Florence Bascom Geoscience Center

Nanoscale Molecular Composition of Solid Bitumen from the Eagle Ford Group Across a Natural Thermal Maturity Gradient

Solid bitumen is a petrographically-defined secondary organic matter residue produced during petroleum generation and subsequent oil transformation. The presence of solid bitumen impacts many shale reservoir properties including porosity, permeability, and hydrocarbon generation and storage, amongst others. Furthermore, solid bitumen reflectance is an important parameter for assessing the thermal
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Energy Resources Program, Geology, Energy & Minerals Science Center

Oil-source rock correlation studies in the unconventional Upper Cretaceous Tuscaloosa marine shale petroleum system, Mississippi and Louisiana, USA (2019)

The U.S. Geological Survey assessed undiscovered unconventional hydrocarbon resources reservoired in the Upper Cretaceous Tuscaloosa marine shale (TMS) of southern Mississippi and adjacent Louisiana in 2018. As part of the assessment, oil- source rock correlations were examined in the study area where operators produce light (38-45 degrees API), sweet oil from horizontal, hydraulically-fractured w
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Energy Resources Program

Data from Nanoscale Molecular Fractionation of Organic Matter within Unconventional Petroleum Source Beds (2019)

Fractionation of petroleum during migration through sedimentary rock matrices has been observed across lengths of meters to kilometers. Selective adsorption of specific chemical moieties at mineral surfaces and/or the phase behavior of petroleum during pressure changes are typically invoked to explain this behavior. Given the current emphasis on unconventional (continuous) resources, there is a ne
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Energy Resources Program

Petroleum geology data from Cenozoic rock samples in the eastern U.S. Gulf Coast collected 2014 to 2016

The U.S. Geological Survey assessed undiscovered petroleum resources in the downdip Paleogene formations of the U.S. Gulf Coast in 2018. During the assessment new data and information were collected to evaluate thermal maturity, source rock character, and unconventional reservoir rock prospectivity for the Cenozoic-aged section in south Louisiana. Samples were analyzed using multiple analytical ap
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Energy Resources Program

Mercury injection capillary pressure data in the U.S. Gulf Coast Tuscaloosa Group in Mississippi and Louisiana collected 2015 to 2017

This data release contains mercury injection capillary pressure (MICP), pseudo-wetting saturation, and carbon dioxide (CO2) column height data for subsurface Tuscaloosa Group samples from Mississippi and Louisiana.
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Energy Resources Program

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 va
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Energy Resources Program

DDT and related compounds in pore water of shallow sediments on the Palos Verdes Shelf, CA

For nearly two and a half decades following World War II, production wastes from the worlds largest manufacturer of technical DDT were discharged into sewers of Los Angeles County. Following treatment, the wastes were released via a submarine outfall system to nearshore coastal waters where a portion accumulated in shallow sediments of the Palos Verdes Shelf (PVS). An investigation of the pore-wat
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Water Resources

Petroleum 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
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Energy Resources Program
Filter Total Items: 113

Hydrous pyrolysis of New Albany Shale: A study examining maturation changes and porosity development

The characterization of nanoscale organic structures has improved our understanding of porosity development within source-rock reservoirs, but research linking organic porosity evolution to thermal maturity has generated conflicting results. To better understand this connection, an immature (0.25% solid bitumen reflectance; BRo) sample of the New Albany Shale was used in four isothermal hydrous py
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Energy Resources Program, Geology, Energy & Minerals Science Center

Compositional evolution of organic matter in Boquillas Shale across a thermal gradient at the single particle level

The molecular composition of petroliferous organic matter and its compositional evolution throughout thermal maturation provides insight for understanding petroleum generation. This information is critical for understanding hydrocarbon resources in unconventional reservoirs, as source rock organic matter is highly dispersed, in contact with the surrounding mineral matrix, and may occur as multiple
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Energy Resources Program, Geology, Energy & Minerals Science Center, Central Energy Resources Science Center

Relating Tmax and hydrogen index to vitrinite and solid bitumen reflectance in hydrous pyrolysis residues: Comparisons to natural thermal indices

Vitrinite reflectance (VRo; %) generally is considered the most reliable technique to determine the thermal maturity of sedimentary rocks. However, it is a time-consuming process to collect reflectance (Ro; %) measurements and is subjective to the interpretation of each trained technician, who must be able to discern between vitrinite and solid bitumen and other organic matter types. Inadvertent m
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Energy Resources Program, Geology, Energy & Minerals Science Center

Organo-facies and mineral effects on sorption capacity of low-maturity Permian Barakar shales from the Auranga Basin, Jharkhand, India

Shales associated with the Lower Permian (Barakar Formation) sediments of the Auranga Coalfield, India, occur in the immature–early mature stage. The sorption capacity of Barakar shale samples has been studied through high-pressure methane (CH4) adsorption and low-pressure N2 gas adsorption (LPN2GA) methods, supported with proximate analyses, programmed pyrolysis, optical petrography, and with ene
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Energy Resources Program, Geology, Energy & Minerals Science Center

A review of spatially resolved techniques and applications of organic petrography in shale petroleum systems

This review examines new techniques and applications of organic petrography in source-rock reservoir petroleum systems that have occurred along with development of the global ‘shale revolution’ in energy resources. The review is limited to techniques and instrumentation that provide spatially resolved information, typically at or below microscales, for dispersed organic matter occurring in situ in
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Ecosystems, Climate Adaptation Science Centers, Climate Adaptation Science Centers, Southwest Climate Science Center, Florence Bascom Geoscience Center, Geology, Energy & Minerals Science Center

Organic geochemistry and petrology of Devonian shale in eastern Ohio: Implications for petroleum systems assessment

Recent production of light sweet oil has prompted reevaluation of Devonian petroleum systems in the central Appalachian Basin. Upper Devonian Ohio Shale (lower Huron Member) and Middle Devonian Marcellus Shale organic-rich source rocks from eastern Ohio and nearby areas were examined using organic petrography and geochemical analysis of solvent extracts to test ideas related to organic matter sour
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Energy Resources Program, Geology, Energy & Minerals Science Center

Organic petrology and geochemistry of the Sunbury and Ohio Shales in eastern Kentucky and southeastern Ohio

As part of a study to determine the origin of oil and gas in the Berea Sandstone in northeastern Kentucky and southeastern Ohio, 158 samples of organic-rich shale from the Upper Devonian Olentangy and Ohio Shales and the Lower Mississippian Sunbury Shale, collectively referred to as the “black shale,” were collected and analyzed from 12 cores. The samples were analyzed for total organic carbon (TO
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Energy Resources Program, Geology, Energy & Minerals Science Center

Oil–source correlation studies in the shallow Berea Sandstone petroleum system, eastern Kentucky

Shallow production of sweet high-gravity oil from the Upper Devonian Berea Sandstone in northeastern Kentucky has caused the region to become the leading oil producer in the state. Potential nearby source rocks, namely, the overlying Mississippian Sunbury Shale and underlying Ohio Shale, are immature for commercial oil generation according to vitrinite reflectance and programmed pyrolysis analyses
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Energy Resources Program, Geology, Energy & Minerals Science Center

Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas Onset (~12.8 ka): High-temperature melting at >2200 °C

At Abu Hureyra (AH), Syria, the 12,800-year-old Younger Dryas boundary layer (YDB) contains peak abundances in meltglass, nanodiamonds, microspherules, and charcoal. AH meltglass comprises 1.6 wt.% of bulk sediment, and crossed polarizers indicate that the meltglass is isotropic. High YDB concentrations of iridium, platinum, nickel, and cobalt suggest mixing of melted local sediment with small qua
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Energy Resources Program, Geology, Energy & Minerals Science Center

Molecular and isotopic gas composition of the Devonian Berea Sandstone and implications for gas evolution, eastern Kentucky

Since 2011, the Devonian Berea Sandstone in northeastern Kentucky has produced oil where thermal maturity studies indicate that likely source rocks, namely, the Devonian Ohio Shale and Mississippian Sunbury Shale, are thermally immature. Downdip, where source rocks are mature for oil, the Berea Sandstone and Ohio Shale primarily produce gas. To investigate this thermal maturity discordancy, the mo
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Energy Resources Program, Geology, Energy & Minerals Science Center

Investigating the effects of broad ion beam milling to sedimentary organic matter: Surface flattening or heat-induced aromatization and condensation?

Previous work has proposed transfer of kinetic heat energy from low-energy broad ion beam (BIB) milling causes thermal alteration of sedimentary organic matter, resulting in increases of organic matter reflectance. Whereas, other studies have suggested the organic matter reflectance increase from BIB milling is due to decreased surface roughness. To test if reflectance increases to sedimentary org
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Energy Resources Program, Geology, Energy & Minerals Science Center

Examination of inertinite within immature Eagle Ford Shale at the nanometer-scale using atomic force microscopy-based infrared spectroscopy

The nanoscale molecular composition of sedimentary organic matter is challenging to characterize in situ given the limited tools available that can adequately interrogate its complex chemical structure. This is a particularly relevant issue in source rocks, as kerogen composition will strongly impact its reactivity and so is critical to understanding petroleum generation processes during catagenes
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Energy Resources Program, Geology, Energy & Minerals Science Center

Photomicrograph Atlas

A database of images related to the characterization of fossil fuel resources in the United States and the world.

By
Energy Resources Program, Geology, Energy & Minerals Science Center

Science and Products