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Thomas Gentzis - One of the best experts on this subject based on the ideXlab platform.
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depositional dynamics of the devonian rocks and their influence on the distribution patterns of Liptinite in the sifa 1x well western desert egypt implications for hydrocarbon generation
Marine and Petroleum Geology, 2021Co-Authors: Walid A Makled, Thomas Gentzis, Atef M Hosny, Doaa A Mousa, Mostafa M Lotfy, Ahmed Abd El A Ghany, Marwa El Z Sawy, Ahmed A Orabi, Heba A Abdelrazak, Wafaa I ShahatAbstract:Abstract Samples from the Devonian succession in the Sifa-1 well located mid-way between the Egyptian Faghur Basin and the Libyan Cyrenaica Platform were examined in this study. The distribution of Liptinite group macerals was investigated under reflected and transmitted light microscopy. Diverse and abundant Liptinite of terrigenous and marine origin were identified. The palynological investigations included analysis of the miospores assemblages and palynofacies categories by multiple statistical approaches in addition to calculation of the sedimentation rates. These analyses signified four miospores biotopes and three palynofacies biotopes that were used to assess the ramps of paleoclimatological and paleoenvironmental changes during sedimentation. These biotopes were used to define a model of Liptinite maceral distribution throughout the Devonian in the study area. The model suggested two different phases of basinal dynamics in terms of climate, sea level, and sedimentation rates, namely an Early-Middle Devonian transgressive phase and a Late Devonian regressive phase. Conditions during the Early-Middle Devonian transgressive phase were oxic to dysoxic with low sedimentation rates and oxic during the Late Devonian regressive phase. Oxygen depletion was above the threshold required to induce significant preservation of the quantity and quality of organic matter, including Liptinite macerals. The redox conditions were confirmed by trace elements analysis. The high oxygen level affected both the quantity and quality of the Liptinite macerals and greatly reduced the preservation of the amorphous organic matter. The quality of the organic matter varied from kerogen type I, II, mixed types II/III and type III. The mixture of these kerogen types was assessed by organic elemental and pyrolysis gas chromatography analyses. In addition, the entire Devonian succession in the Sifa-1 well is in the oil window, as also indicated by miospore coloration. This indicates that the organic matter in the Devonian strata have the potential to generate oil and gas.
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Preliminary Investigation of the Effects of Thermal Maturity on Redox-Sensitive Trace Metal Concentration in the Bakken Source Rock, North Dakota, USA.
ACS omega, 2020Co-Authors: Arash Abarghani, Thomas Gentzis, Bo Liu, Seyedalireza Khatibi, Bailey Bubach, Mehdi OstadhassanAbstract:Samples were taken at different levels of thermal maturity in the unconventional Bakken source rock. Programmed pyrolysis derived Tmax, solid bitumen reflectance, Liptinite group maceral UV fluores...
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Elemental concentration and organic petrology of unique Liptinite-rich humic coal, canneloid shale, and cannel coal of Devonian age from Arctic Canada
Chemical Geology, 2018Co-Authors: Fariborz Goodarzi, Thomas GentzisAbstract:Abstract Seventeen coal and carbonaceous shale samples taken from eight stratigraphic sections of the Devonian Hecla Bay and Weatherall formations in Arctic Canada, were examined using reflected light microscopy, instrumental neutron activation analysis (INAA), and inductively coupled plasma emission spectroscopy (ICPES). Samples consist of humic coal with 62–79 vol% vitrinite, Liptinite-rich humic coal with 42 vol% Liptinite, and cannel coal with 52–81 vol% sporinite content. Carbonaceous shale has 46–73 vol% mineral matter and canneloid shale has 30–42 vol% mineral matter as well as 22–38 vol% sporinite content. Most were deposited in areas characterized by minor channel cut-and-abandonment and lake and bay infills peripheral to distributary complexes. A fresh water environment is indicated by Boron (18–71 ppm), low inertinite (0–7.8 wt%), and high sporinite content (30–81 vol%). The ratio of Na/K versus Liptinite content shows that coals and associated sediments from the Hecla Bay Formation experienced a more rapid rate of sedimentation than the carbonaceous shales from the Weatherall Formation. The highest total REEs and LREE (La-Gd) was in the Liptinite-rich humic coal, followed by humic coal and carbonaceous shale. The concentration of REEs and LREEs in the cannel coals is half of that measured in the Liptinite-rich humic coal. The PAAS normalized for oil shales follows two different patterns: 1) the Liptinite-rich coal samples display a sharp increase from Nd to Ho, then maintain a similar pattern up to Lu; and 2) samples of other lithologies increase from Nd to Dy, and then maintain a flat trend up to Lu. Hierarchical cluster analysis shows that canneloid and Liptinite-rich coal exhibit the greatest similarity with each other whereas humic coal and Liptinite-rich coal show the greatest dissimilarity with carbonaceous shale.
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Elemental concentration and organic petrology of unique Liptinite-rich humic coal, canneloid shale, and cannel coal of Devonian age from Arctic Canada
Chemical Geology, 2018Co-Authors: Fariborz Goodarzi, Thomas GentzisAbstract:Abstract Seventeen coal and carbonaceous shale samples taken from eight stratigraphic sections of the Devonian Hecla Bay and Weatherall formations in Arctic Canada, were examined using reflected light microscopy, instrumental neutron activation analysis (INAA), and inductively coupled plasma emission spectroscopy (ICPES). Samples consist of humic coal with 62–79 vol% vitrinite, Liptinite-rich humic coal with 42 vol% Liptinite, and cannel coal with 52–81 vol% sporinite content. Carbonaceous shale has 46–73 vol% mineral matter and canneloid shale has 30–42 vol% mineral matter as well as 22–38 vol% sporinite content. Most were deposited in areas characterized by minor channel cut-and-abandonment and lake and bay infills peripheral to distributary complexes. A fresh water environment is indicated by Boron (18–71 ppm), low inertinite (0–7.8 wt%), and high sporinite content (30–81 vol%). The ratio of Na/K versus Liptinite content shows that coals and associated sediments from the Hecla Bay Formation experienced a more rapid rate of sedimentation than the carbonaceous shales from the Weatherall Formation. The highest total REEs and LREE (La-Gd) was in the Liptinite-rich humic coal, followed by humic coal and carbonaceous shale. The concentration of REEs and LREEs in the cannel coals is half of that measured in the Liptinite-rich humic coal. The PAAS normalized for oil shales follows two different patterns: 1) the Liptinite-rich coal samples display a sharp increase from Nd to Ho, then maintain a similar pattern up to Lu; and 2) samples of other lithologies increase from Nd to Dy, and then maintain a flat trend up to Lu. Hierarchical cluster analysis shows that canneloid and Liptinite-rich coal exhibit the greatest similarity with each other whereas humic coal and Liptinite-rich coal show the greatest dissimilarity with carbonaceous shale.
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PETROLOGY AND GEOCHEMISTRY OF CANADIAN Liptinite-RICH COALS
1991 International Conference on Coal Science Proceedings, 1991Co-Authors: Thomas Gentzis, Fariborz Goodarzi, Lloyd R. Snowdon, Martin G. FowlerAbstract:Publisher Summary This chapter explores the chemical and petrological character of selected coals from the Rocky Mountain Front Ranges of southeastern British Columbia, the Foothills Region of Alberta, and the Canadian Arctic Archipelago. The needle coals are rich in resinite, cutinite, sporinite, liptodetrinite and bituminite, with minor vitrinite and inertinite. Bituminite has been subdivided into bituminite II and III and is weakly to strongly oxidized, as evident by its fluorescence intensity. In addition, biological alteration is often marked by the presence of fungal hyphae on fluorescing bituminite fragments. Bituminite is the major constituent of the needle coals and may form via chemical or bacterial decomposition of animal, planktonic, or bacterial lipids. A suppression of vitrinite reflectance by as much as 0.3% is very likely in these coals.
Fariborz Goodarzi - One of the best experts on this subject based on the ideXlab platform.
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Elemental concentration and organic petrology of unique Liptinite-rich humic coal, canneloid shale, and cannel coal of Devonian age from Arctic Canada
Chemical Geology, 2018Co-Authors: Fariborz Goodarzi, Thomas GentzisAbstract:Abstract Seventeen coal and carbonaceous shale samples taken from eight stratigraphic sections of the Devonian Hecla Bay and Weatherall formations in Arctic Canada, were examined using reflected light microscopy, instrumental neutron activation analysis (INAA), and inductively coupled plasma emission spectroscopy (ICPES). Samples consist of humic coal with 62–79 vol% vitrinite, Liptinite-rich humic coal with 42 vol% Liptinite, and cannel coal with 52–81 vol% sporinite content. Carbonaceous shale has 46–73 vol% mineral matter and canneloid shale has 30–42 vol% mineral matter as well as 22–38 vol% sporinite content. Most were deposited in areas characterized by minor channel cut-and-abandonment and lake and bay infills peripheral to distributary complexes. A fresh water environment is indicated by Boron (18–71 ppm), low inertinite (0–7.8 wt%), and high sporinite content (30–81 vol%). The ratio of Na/K versus Liptinite content shows that coals and associated sediments from the Hecla Bay Formation experienced a more rapid rate of sedimentation than the carbonaceous shales from the Weatherall Formation. The highest total REEs and LREE (La-Gd) was in the Liptinite-rich humic coal, followed by humic coal and carbonaceous shale. The concentration of REEs and LREEs in the cannel coals is half of that measured in the Liptinite-rich humic coal. The PAAS normalized for oil shales follows two different patterns: 1) the Liptinite-rich coal samples display a sharp increase from Nd to Ho, then maintain a similar pattern up to Lu; and 2) samples of other lithologies increase from Nd to Dy, and then maintain a flat trend up to Lu. Hierarchical cluster analysis shows that canneloid and Liptinite-rich coal exhibit the greatest similarity with each other whereas humic coal and Liptinite-rich coal show the greatest dissimilarity with carbonaceous shale.
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Elemental concentration and organic petrology of unique Liptinite-rich humic coal, canneloid shale, and cannel coal of Devonian age from Arctic Canada
Chemical Geology, 2018Co-Authors: Fariborz Goodarzi, Thomas GentzisAbstract:Abstract Seventeen coal and carbonaceous shale samples taken from eight stratigraphic sections of the Devonian Hecla Bay and Weatherall formations in Arctic Canada, were examined using reflected light microscopy, instrumental neutron activation analysis (INAA), and inductively coupled plasma emission spectroscopy (ICPES). Samples consist of humic coal with 62–79 vol% vitrinite, Liptinite-rich humic coal with 42 vol% Liptinite, and cannel coal with 52–81 vol% sporinite content. Carbonaceous shale has 46–73 vol% mineral matter and canneloid shale has 30–42 vol% mineral matter as well as 22–38 vol% sporinite content. Most were deposited in areas characterized by minor channel cut-and-abandonment and lake and bay infills peripheral to distributary complexes. A fresh water environment is indicated by Boron (18–71 ppm), low inertinite (0–7.8 wt%), and high sporinite content (30–81 vol%). The ratio of Na/K versus Liptinite content shows that coals and associated sediments from the Hecla Bay Formation experienced a more rapid rate of sedimentation than the carbonaceous shales from the Weatherall Formation. The highest total REEs and LREE (La-Gd) was in the Liptinite-rich humic coal, followed by humic coal and carbonaceous shale. The concentration of REEs and LREEs in the cannel coals is half of that measured in the Liptinite-rich humic coal. The PAAS normalized for oil shales follows two different patterns: 1) the Liptinite-rich coal samples display a sharp increase from Nd to Ho, then maintain a similar pattern up to Lu; and 2) samples of other lithologies increase from Nd to Dy, and then maintain a flat trend up to Lu. Hierarchical cluster analysis shows that canneloid and Liptinite-rich coal exhibit the greatest similarity with each other whereas humic coal and Liptinite-rich coal show the greatest dissimilarity with carbonaceous shale.
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PETROLOGY AND GEOCHEMISTRY OF CANADIAN Liptinite-RICH COALS
1991 International Conference on Coal Science Proceedings, 1991Co-Authors: Thomas Gentzis, Fariborz Goodarzi, Lloyd R. Snowdon, Martin G. FowlerAbstract:Publisher Summary This chapter explores the chemical and petrological character of selected coals from the Rocky Mountain Front Ranges of southeastern British Columbia, the Foothills Region of Alberta, and the Canadian Arctic Archipelago. The needle coals are rich in resinite, cutinite, sporinite, liptodetrinite and bituminite, with minor vitrinite and inertinite. Bituminite has been subdivided into bituminite II and III and is weakly to strongly oxidized, as evident by its fluorescence intensity. In addition, biological alteration is often marked by the presence of fungal hyphae on fluorescing bituminite fragments. Bituminite is the major constituent of the needle coals and may form via chemical or bacterial decomposition of animal, planktonic, or bacterial lipids. A suppression of vitrinite reflectance by as much as 0.3% is very likely in these coals.
Cortland F Eble - One of the best experts on this subject based on the ideXlab platform.
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petrology and palynology of select coal samples from the permian waterberg coalfield south africa
International Journal of Coal Geology, 2019Co-Authors: Nicola J Wagner, James C. Hower, Cortland F Eble, Rosemary FalconAbstract:Abstract The petrology and palynology of coals from the Permian-aged Waterberg Coalfield, situated in the Limpopo Province of South Africa, are considered. The Waterberg Coalfield contains a significant portion of the country's coal reserves, but is still comparatively underexplored. Detailed maceral analyses, combined maceral-microlithotype analyses, mean random and maximum vitrinite reflectance analyses, etching, and palynology studies were undertaken on coals from four productive horizons. There is a general upward trend in vitrinite content through the sequence (15–59 vol% mineral matter free), dominated by collotelinite, along with a slight decrease in coal rank. The lower Vryheid Formation coal has a comparatively low mineral matter and high inertinite content, dominated by inertodetrinite. The upper Grootegeluk Formation samples contain above 35 vol% mineral matter, and Liptinite contents ranging from 14 to 21 vol%. The use of blue-light fluorescence in conjunction with incident light (single-scan method) revealed that Liptinite is intimately associated with inertodetrinite and mineral matter, specifically clays and occasionally pyrite. It is evident that the Liptinite maceral content has previously been under-reported in the Waterberg coals. The palynofloras correlate with the well-studied Witbank Coalfield. The petrography, along with the palynology, essentially confirm the palaeoenvironment of the Karoo Basin as progressing from a cooler, more oxidising environment, to a wetter, seasonal environment.
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organic petrology of carbondale formation coal beds and marine roof shales in western kentucky eastern interior illinois basin usa
International Journal of Coal Geology, 2012Co-Authors: Cortland F EbleAbstract:Abstract Ten samples of Carbondale Formation (late Middle Pennsylvanian, Westphalian D) roof shale strata from the Western Kentucky Coal Field (Eastern Interior Basin, USA) were analyzed petrographically to gain a better understanding of the organic composition of the shales. The samples were collected in conjunction with a coal bed methane exploration program, so a direct comparison of the organic composition of the shales, and the coal beds that directly underlie them, could be made. Petrographically, total vitrinite contents in the shales average 20.8% (mineral matter free basis, mmf), which is significantly lower than the average vitrinite content of Carbondale Formation coal beds (avg. 81.8%, mmf; n = 32). In contrast, total Liptinite contents average 49.7% (mmf) in the shales, which is significantly higher than the average Liptinite content of Carbondale coals (avg. 7.0%, mmf). Amorphinite and bituminite were found to be the most abundant Liptinite macerals in the shales, but were not recorded from the coal samples. Likewise, total inertinite contents were much higher in the shales (avg. 29.6%, mmf), than in the coals (avg. 11.0%, mmf). A type of macrinite identified as “granular macrinite” was the dominant inertinite maceral in the shales, but was absent in the coal samples. Although the average desorbed gas contents of Carbondale Formation coals and shales are low and currently uneconomical (avg. 0.9 ml/g [28.8 scf/ton] for the shales, 2.4 ml/g [76.9 scf/ton] for the coals, as received basis), they nonetheless represent a potential future gas resource.
R. Marc Bustin - One of the best experts on this subject based on the ideXlab platform.
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Micro-FTIR spectroscopy of Liptinite macerals in coal
International Journal of Coal Geology, 1998Co-Authors: R. Marc BustinAbstract:Abstract Reflectance FTIR microspectroscopy has been used to investigate the chemical structure of the Liptinite macerals, alginite, bituminite, sporinite, cutinite and resinite in bituminous coals of Carboniferous to Tertiary age. In comparison with the spectra of vitrinite in the same coals, the micro-FTIR spectra of Liptinite macerals are characterized by stronger aliphatic CH x absorptions at 3000–2800 and 1460–1450 cm −1 , less intense aromatic CC ring stretching vibration and aromatic CH out of plane deformation at 1610–1560 and 900–700 cm −1 respectively and various intense acid CO group absorptions at 1740–1700 cm −1 . The peaks at 1000–900 cm −1 due to aliphatic CH 2 wagging vibrations in olefins and at 730–720 cm −1 due to CH 2 rocking vibration in long chain aliphatic substances ([CH 2 ] n , n ≥4), are characteristic of Liptinite macerals. Collectively the micro-FTIR spectral characteristics indicate that Liptinite is composed of greater numbers of long chain aliphatics, fewer aromatics and a broader range of oxygen-containing groups than other macerals. Marked differences exist in micro-FTIR spectra within the Liptinite maceral group. Alginite has the strongest aliphatic and least aromatic absorptions followed by bituminite, resinite, cutinite and sporinite. The aliphatic components in alginite are the longest chained and least branched whereas those in sporinite are the shortest chained and most branched. Bituminite, resinite and cutinite are intermediate. Notable differences in micro-FTIR spectra of individual Liptinite macerals, such as intensities and peak locations of aromatic CC in alginite, CO groups in bituminite and resinite and substituted aromatic CH and C–O–C groups in cutinite and sporinite, also exist, which are attributed to differences in depositional environments or biotaxonomy.
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Variation in vitrinite chemistry as a function of associated Liptinite content; a microprobe and FT-i.r. investigation
Organic Geochemistry, 1993Co-Authors: Maria Mastalerz, K.r. Wilks, R. Marc BustinAbstract:Variations in vitrinite chemistry have been studied with reference to the content of Liptinite associated with vitrinite. Electron microprobe and FT-i.r. techniques have been used to determine elemental composition and functional group distribution, respectively, whereas Rock-Eval pyrolysis was utilized to investigate the influence of hydrocarbons on vitrinite chemistry. Our study shows that C and O content decrease and H content increases as Liptinite content increases. On a molecular scale, the changes are expressed by an increase in aliphatic H and decrease in aromatic H as Liptinite content increases. FT-i.r. spectra of KBr pellets indicate that differences in the quantity of free hydrocarbons influence the functional group distribution in vitrinite. Possible reasons for the evolution in vitrinite chemistry as a content of associated Liptinite changes are discussed.
Andrew E. Pomerantz - One of the best experts on this subject based on the ideXlab platform.
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Suppression of vitrinite reflectance by bitumen generated from Liptinite during hydrous pyrolysis of artificial source rock
Organic Geochemistry, 2018Co-Authors: K.e. Peters, Paul C. Hackley, J.j. Thomas, Andrew E. PomerantzAbstract:Abstract Mean random vitrinite reflectance (Ro) is the most widely accepted method to determine thermal maturity of coal and other sedimentary rocks. However, oil-immersion Ro of polished rock or kerogen samples is commonly lower than Ro values measured in samples from adjacent vitrinite-rich coals that have undergone the same level of thermal stress. So-called suppressed Ro values have also been observed in hydrous pyrolysis experiments designed to simulate petroleum formation. Various hypotheses to explain Ro suppression, such as sorption of products generated from Liptinite during maturation, diagenetic formation of perhydrous vitrinite or overpressure, remain controversial. To experimentally test for suppression of vitrinite reflectance, artificial rock was prepared using silica and a calcined blend of limestone and clay with various proportions of thermally immature vitrinite-rich Wyodak-Anderson coal and Liptinite-rich kerogen isolated from the oil-prone Parachute Creek Member of the Green River Formation. The samples were subjected to hydrous pyrolysis for 72 h. at isothermal temperatures of 300 °C, 330 °C, and 350 °C to simulate burial maturation. Compared to artificial rock that contains only coal, samples with different proportions of oil-prone kerogen show distinct suppression of calibrated Ro at 300 °C and 330 °C. The reflectance of solid bitumen generated during heating of the samples is lower than that of the associated vitrinite and does not interfere with the Ro measurements. These results provide the first experimental evidence that Ro suppression occurs in vitrinite mixed with Liptinite-rich kerogen in a rock matrix. Although the precise chemical mechanism for Ro suppression by Liptinite remains unclear, free radicals generated from solid bitumen and associated volatile products during maturation of Liptinite may contribute to termination reactions that slow the aromatization and rearrangement of polyaromatic sheets in vitrinite, thus suppressing Ro. This mechanism does not preclude Ro suppression that might result from overpressure or differences in redox conditions during diagenesis.