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To test if reflectance increases to sedimentary organic matter (vitrinite) caused by broad ion beam (BIB) milling were related to molecular aromatization and condensation, we used Raman and Fourier transform infrared (FTIR) spectroscopies to evaluate potential compositional changes in the same vitrinite locations pre- and post-BIB milling. The same locations also were examined by atomic force microscopy (AFM) to determine topographic changes caused by BIB milling (as expressed by the areal root-mean-square roughness parameter Rq). Samples consisted of four medium volatile bituminous coals. We used a non-aggressive BIB milling approach with conditions of [(5 min, 4 keV, 15°incline, 360° rotation at 25 rpm and 100%...
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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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This study presents Raman spectroscopic data paired with scanning electron microscopy (SEM) to assess solid bitumen composition and porosity development as a function of solid bitumen texture and association with minerals. A series of hydrous pyrolysis experiments (1-103 days, 300-370°C) using a low maturity (0.25% solid bitumen reflectance, BRo), high total organic carbon [(TOC), 14.0 wt. %] New Albany Shale sample as the starting material yielded pyrolysis residues designed to evaluate the evolution of TOC, solid bitumen aromaticity, and organic porosity development with increasing temperature and heating duration. Solid bitumen was analyzed by Raman spectroscopy wherein point data was collected from accumulations...
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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 geochronologic information is limited by our inability to predict internal zonation from observations of whole zircon grains. Here we document the use of a petrographic microscope to observe and image the photoluminescence (PL) response of whole zircon grains excited under ultraviolet (UV) light, and the utility of this PL...
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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...
As more hydrocarbon production from hydraulic fracturing and other methods produce large volumes of water, innovative methods must be explored for treatment and reuse of these waters. However, understanding the general water chemistry of these fluids is essential to providing the best treatment options optimized for each producing area. Machine learning algorithms can often be applied to datasets to solve complex problems. In this study, we used the U.S. Geological Survey’s National Produced Waters Geochemical Database (USGS PWGD) in an exploratory exercise to determine if systematic variations exist between produced waters and geologic environment that could be used to accurately classify a water sample to a given...
Categories: Data; Tags: Alabama, Alaska, Alaska Region, Arizona, Arkansas, All tags...
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Fluorescence spectroscopy via confocal laser scanning microscopy (CLSM) was used to analyze ancient sedimentary organic matter, including Tasmanites microfossils in Devonian shale and Gloecapsomorpha prisca (G. prisca) in Ordovician kukersite from North American basins. We examined fluorescence emission as a function of excitation laser wavelength, sample orientation, and with respect to location within individual organic entities and along organic matter chemical transects. Results from spectral scans of the same field of view in Tasmanites with different laser lines showed progressive red-shift in emission maxima with longer excitation wavelengths. This result indicates steady-state Tasmanites fluorescence emission...
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Waters co-produced during petroleum extraction are the largest waste stream from oil and gas development. Reuse or disposal of these waters is difficult due both to their high salinities, which can greatly exceed 35 g/L (seawater equivalent), and also the sheer volume of wastewater generated, which is estimated at nearly 900 billion gallons per year across the United States. Beyond disposal concerns, produced water may also represent a possible source of valuable mineral commodities. While an understanding of the trace element composition of produced water is required for evaluating the associated resource and waste potential of these materials, measuring trace elements in high salinity brines is challenging due...
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The Permian Basin, straddling New Mexico and Texas, is one of the most productive oil and gas (OG) provinces in the United States. OG production yields large volumes of wastewater that contain elevated concentrations of major ions including salts (also referred to as brines), and trace organic and inorganic constituents. These OG wastewaters pose unknown environmental health risks, particularly in the case of accidental or intentional releases. Releases of OG wastewaters have resulted in water-quality and environmental health effects at sites in West Virginia (Akob, et al., 2016, Orem et al. 2017, Kassotis et al. 2016) and in the Williston Basin region in Montana and North Dakota (Cozzarelli et al. 2017, Cozzarelli...
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A suite of slate samples collected along a 2 km transect crossing the Lishan Fault in central Taiwan were evaluated to assess the role of ductile strain energy in natural graphitization at greenschist facies metamorphic conditions. Scanning electron microscope (SEM) imaging documents phyllosilicate and quartz replacement textures consistent cleavage development via dissolution-precipitation processes that increase in intensity from east to west. X-ray diffraction data reveal an east-to-west linear decrease in the full-width-at-half-maximum (FWHM) values of the 004 muscovite peaks and shifts towards higher 2θ (lower d) values. Rietveld refinements required two distinct muscovite populations and muscovite microstrain...
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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 need to understand petroleum fractionation occurring during expulsion and migration at the nanometer to micron scale, due to the fine-grained nature of petroliferous mudrocks. Here organic matter compositional differences observed within kukersite petroleum source beds (containing acritarch Gloeocapsomorpha prisca) from the...
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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 most commonly used parameter for thermal maturity calibration in basin modelling is mean random vitrinite reflectance (Ro). However, Ro suppression, or lower than expected Ro, has been noted in samples containing a high proportion of liptinite macerals. This has been empirically demonstrated using hydrous pyrolysis experiments of artificial source rock containing various proportions of thermally immature Wyodak-Anderson coal and liptinite-rich kerogen from the Parachute Creek Member of the Green River Formation. Analysis of samples pyrolyzed at 330°C for 72 h demonstrates that the Ro values of both vitrinite and solid bitumen are suppressed, where the degree of suppression increases with increasing amounts of...
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Here we report ultra-high resolution infrared mapping of organic matter functional group distribution in Tasmanites (algal microfossils) from the Upper Devonian Ohio Shale using optical photothermal infrared spectroscopy (O-PTIR). O-PTIR is capable of rapidly measuring the vibrational response of samples in situ with ~500-nm spatial resolution, well below the infrared diffraction limit. Our results indicate that organic matter within the fold apices regions (zones of greatest deformation) of relatively large Tasmanites is more aliphatic and less oxygen-rich than organic matter in the surrounding Tasmanites body. This contrasts with data from relatively thinner Tasmanites which show statistically invariant chemical...
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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 evaluated carbonaceous shales proximal to coal measures and coal samples via isothermal hydrous pyrolysis (HP) to compare differences in the maturation pathways of vitrinite in different matrices and with different starting aromaticity. Sample residues were analysed via vitrinite reflectance (VRo), geochemical screening tests (organic carbon and programmed temperature pyrolysis), and infrared spectroscopy. The study included samples from Indian and North American basins, to observe differences in vitrinite evolution with respect to enclosing mineral matrix, starting degree of aromaticity, organic matter types, stratigraphic age, and depositional environment. Tmax, production index (PI), and VRo show intuitive...


map background search result map search result map High Microscale Variability in Raman Thermal Maturity Estimates from Shale Organic Matter - Data Release Nanoscale Molecular Fractionation of Organic Matter within Unconventional Petroleum Source Beds (2019) Direct Trace Element Determination in Oil and Gas Produced Waters with Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES): Advantages of High Salinity Tolerance (2019) Fluorescence spectroscopy of ancient sedimentary organic matter via confocal laser scanning microscopy (CLSM) Investigating the effects of broad ion beam milling to sedimentary organic matter 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 Photoluminescence Imaging of Whole Zircon Grains on a Petrographic Microscope—An Underused Aide for Geochronologic Studies Input Files and Code for: Machine learning can accurately assign geologic basin to produced water samples using major geochemical parameters Reflectance, Raman band separation and Mean multivariant curve resolution (MCR) in organic matter in Boquillas Shale Solid bitumen and vitrinite reflectance suppression explored using hydrous pyrolysis of artificial source rock (2021) TOC, Reflectance and Raman Data from Eocene Green River Mahogany zone Geochemistry and microbiology data collected to study the effects of oil and gas wastewater dumping on arid lands in New Mexico Textural occurrence and organic porosity of solid bitumen in shales Strain induced molecular heterogeneity in ancient sedimentary organic matter mapped at nanoscales using optical photothermal infrared spectroscopy Evidence for strain induced graphitization across a ductile fault zone 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 Geochemistry and microbiology data collected to study the effects of oil and gas wastewater dumping on arid lands in New Mexico Solid bitumen and vitrinite reflectance suppression explored using hydrous pyrolysis of artificial source rock (2021) Nanoscale Molecular Fractionation of Organic Matter within Unconventional Petroleum Source Beds (2019) Evidence for strain induced graphitization across a ductile fault zone TOC, Reflectance and Raman Data from Eocene Green River Mahogany zone Textural occurrence and organic porosity of solid bitumen in shales Atomic Force Microscopy-based Infrared Spectroscopy Data within Immature Eagle Ford Shale at the Nanometer-scale Investigating the effects of broad ion beam milling to sedimentary organic matter Photoluminescence Imaging of Whole Zircon Grains on a Petrographic Microscope—An Underused Aide for Geochronologic Studies Fluorescence spectroscopy of ancient sedimentary organic matter via confocal laser scanning microscopy (CLSM) Results of leaching experiments on 12 energy-related shales from the United States Direct Trace Element Determination in Oil and Gas Produced Waters with Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES): Advantages of High Salinity Tolerance (2019) Input Files and Code for: Machine learning can accurately assign geologic basin to produced water samples using major geochemical parameters SEM-CL investigation of sedimentary organic matter samples