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Filters: partyWithName: Justin E Birdwell (X) > partyWithName: Aaron M Jubb (X) > partyWithName: U.S. Geological Survey - ScienceBase (X)

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Petroleum within unconventional source-rock reservoirs is hosted in organic matter and mineral pore space as well as in voids and microfractures. Recent work has shown that for source-rock reservoirs in the dry gas window, significant portions of methane (CH4), the main component of petroleum at elevated maturities, can be stored within fine organic matter porosity. However, within reservoirs at lower thermal maturities (e.g., peak oil or wet-gas conditions), the distribution and behavior of CH4 and the higher alkanes that comprise gas condensates across pore sizes is unclear, especially for fine pores with diameters <50 nm. Understanding CH4 within these settings provides insight for petroleum generation, movement,...
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Inorganic compositions of flowback and co-produced waters from hydrocarbon extraction have been studied directly and through laboratory experiments that seek to replicate subsurface water-rock interaction. Here a broad analysis is made of compositions from the U.S. Geological Survey Produced Waters Database (v2.3) and leachates (water, hydrochloric acid, artificial brine) for 12 energy-resource related shales from across the United States. The database illustrates common ranges for 26 elements in 4 produced water types and enhanced solubility with increasing ionic strength is observed for Al, Ba, Fe, Li, Mn, Rb, Sr, and possibly 11 other elements. Differences are observed between laboratory leachates and produced...
Geological models for petroleum generation suggest thermal conversion of oil-prone sedimentary organic matter in the presence of water promotes increased liquid saturate yield, whereas absence of water causes formation of an aromatic, cross-linked solid bitumen residue. To test the influence of exchangeable hydrogen from water, organic-rich (22 wt.% total organic carbon, TOC) mudrock samples from the Eocene lacustrine Green River Mahogany zone oil shale were pyrolyzed under hydrous and anhydrous conditions at temperatures between 300 and 370°C for 72 hrs. Petrographic approaches including optical microscopy, reflectance, Raman spectroscopy, and scanning electron and transmission electron microscopy, supplemented...
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High-resolution scanning electron microscopy (SEM) visualization of sedimentary organic matter (SOM) is widely utilized in the geosciences for evaluation of microscale rock properties relevant to depositional environment, diagenesis, and the processes of fluid generation, transport, and storage. However, despite thousands of studies which have incorporated SEM approaches, the inability of SEM to differentiate SOM types has hampered the pace of scientific advancement. In this study, we show that SEM-cathodoluminescence (CL) properties can be used to identify and characterize SOM at low thermal maturity conditions. Eleven varied mudstone samples with a broad array of SOM types, ranging from the Paleoproterozoic to...
The nanoscale molecular composition of kerogen is a challenging parameter to characterize given the chemical and structural complexity exhibited by this important biopolymer. However, kerogen composition will strongly impact its reactivity and so is a critical parameter to understand petroleum generation processes during kerogen catagenesis. The recent advent of tip-enhanced analytical methods, such as atomic force microscopy-based infrared spectroscopy (AFM-IR), has allowed for the major compositional features of kerogen to be elucidated at spatial resolutions at or below 50 nm. Here we apply AFM-IR to examine inertinite, an important kerogen maceral type, from an immature Eagle Ford Shale sample. Our data show...
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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 maturity of formations with little to no vitrinite. While the molecular composition of solid bitumen will strongly impact associated parameters such as the development of organic matter porosity, hydrocarbon generation, and optical reflectance, assessing the molecular composition of solid bitumen in situ within shale reservoirs...
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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 vary widely across distances of ≤5 µm within the same organic domain.
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The molecular composition of petroliferous organic matter and its composition evolution throughout thermal advance are key to understanding and insight into petroleum generation. This information is critical for comprehending hydrocarbon resources in unconventional reservoirs, as source rock organic matter is highly dispersed, in contact with the surrounding mineral matrix, and may be present as multiple organic matter types. Here, a combination of Raman spectroscopy and optical microscopy approaches was applied to a marginally mature (vitrinite reflectance ~0.5%) sample of the Late Cretaceous Boquillas Shale before and after hydrous pyrolysis (HP) at 300 °C and 330 °C for 72 hours. This experimental design allowed...
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This study presents a simplified method and empirical relationships for determining organic matter thermal maturity using a portable Raman system equipped with a 785 nm laser, for analysis of crushed, whole-rock samples. Several sets of rocks comprised of shale and coal samples with various mineralogical composition, thermal maturity, total organic carbon (TOC), and age were used to test the method and build correlations between Raman band separation (RBS) values and traditional thermal maturity indicators; organic matter reflectance (Ro) and programmed temperature pyrolysis (Tmax) values. Several sample preparation methods were tested on cuttings material and standard deviation values for RBS were minimized by...


    map background search result map search result map High Microscale Variability in Raman Thermal Maturity Estimates from Shale Organic Matter - Data Release Nanoscale Molecular Composition of Solid Bitumen from the Eagle Ford Group Across a Natural Thermal Maturity Gradient Results of leaching experiments on 12 energy-related shales from the United States Atomic Force Microscopy-based Infrared Spectroscopy Data within Immature Eagle Ford Shale at the Nanometer-scale Reflectance, Raman band separation and Mean multivariant curve resolution (MCR) in organic matter in Boquillas Shale TOC, Reflectance and Raman Data from Eocene Green River Mahogany zone Portable Raman spectroscopic analysis of bulk crushed rock Total neutron scattering of methane in Niobrara Formation samples at the wet-gas maturity level SEM-CL investigation of sedimentary organic matter samples Total neutron scattering of methane in Niobrara Formation samples at the wet-gas maturity level High Microscale Variability in Raman Thermal Maturity Estimates from Shale Organic Matter - Data Release Reflectance, Raman band separation and Mean multivariant curve resolution (MCR) in organic matter in Boquillas Shale TOC, Reflectance and Raman Data from Eocene Green River Mahogany zone Atomic Force Microscopy-based Infrared Spectroscopy Data within Immature Eagle Ford Shale at the Nanometer-scale Results of leaching experiments on 12 energy-related shales from the United States Portable Raman spectroscopic analysis of bulk crushed rock SEM-CL investigation of sedimentary organic matter samples