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J S Esterle - One of the best experts on this subject based on the ideXlab platform.
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electrofacies analysis using high resolution wireline geophysical data as a proxy for inertinite rich coal distribution in late permian coal seams bowen basin
International Journal of Coal Geology, 2015Co-Authors: Alexandra Roslin, J S EsterleAbstract:This paper examines the stratigraphic and geographic distribution of coal composition in main Late Permian coal measures in the Bowen Basin, using coal electrofacies as a proxy for inertinite Maceral Group content. Data for this research were derived from some 26 wells in the northern part of the Bowen Basin. A companion paper (Roslin and Esterle, 2015, in review) introduced the methodology, which is based on electrofacies analysis and uses high-resolution wireline data (including microresistivity from Compact Micro-Image (CMI) tool and Photoelectric Factor (PEF) data in addition to conventional gamma ray, density and laterolog resistivity) to obtain coal electrofacies. Validation of the methodology was performed by comparison of the weighted average proportion of coal electrofacies to the weighted average proportion of the corresponding coal lithotypes obtained from millimetre scale logging and to the percentage gathered from Maceral content analysis. The weighted average proportion of the interpreted dull inertinite-rich coal electrofacies (independent of rank and heat effects) was then analysed to determine their stratigraphic and geographic distribution. From the base upward, the main Late Permian coal bearing units are the Moranbah Coal Measure (MCM), Fort Cooper Coal Measure (FCCM), and Rangal Coal Measure (RCM) and their stratigraphic equivalents across the basin. The proportion of inertinite-rich dull coal electrofacies increases upwards in the RCM, with some thick and merged seams showing distinctive electrofacies signatures. Within the study area, the coal measures and individual seams split from north to south, reflecting increased subsidence and sediment influx into basin depocentres. As the seams split, the proportion of inertinite-rich dull coal electrofacies decreases in the tested sample set.
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evidence for a tidally influenced upper carboniferous ombrogenous mire system upper bench beckley bed westphalian a southern west virginia
Journal of Sedimentary Research, 1992Co-Authors: James R Staub, J S EsterleAbstract:A discontinuous portion of the upper bench of the Beckley bed (Westphalian A) in southern West Virginia was examined in regard to its areal distribution, horizontal and vertical trends in chemistry, horizontal trends in petrographic composition, and its facies relationships with encasing sediments. The results of this examination were compared to those of a process model for the development of ombrogenous mire systems in tidally influenced coastal areas of Sarawak, East Malaysia. The results of these comparisons suggest a strong parallel between the two areas. The ombrogenous mire system that formed the upper bench of the Beckley bed initially developed as small individual topogenous peat swamps in a tidal flat setting. With time, the small individual peat swamps coalesced into an ombrogenous mire system that resulted in a coal bench that covers about 65 sq km. The mire system was eventually covered by channel deposits from a deltaic distributary system. The mire system that developed for the coal bench shows distinct zonation of dull and bright macrolithotypes (dull on the margins and bright in the interior) and contains high concentrations of ash and sulfur in its margins and base. Coal thickness, chemistry and petrographic data allow differentiation of the raised interior from the more topogenous areas of the mire. The interior portions are interpreted as those areas of the bench that are > 65 cm thick and average > 85% vitrinite Group Macerals, 5.5% ash and 0.60% sulfur. The more topogenous areas of the mire system, which were subjected to flooding, oxidation and sediment influx are < 65 cm thick and average < 65% vitrinite Group Macerals, 15.1% ash and 1.81% sulfur. In addition, the amount of preserved cell structure, irrespective of Maceral Group, appears to increase toward the margins of the bench. These trends are consistent with observations in the peat deposits of Sarawak, East Malaysia.
John C Crelling - One of the best experts on this subject based on the ideXlab platform.
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temperature programmed combustion studies of coal and Maceral Group concentrates
Fuel, 1997Co-Authors: Jimmy B Milligan, Mark K Thomas, John C CrellingAbstract:Abstract Temperature-programmed combustion profiles of coals and their Maceral Group concentrates were obtained by thermogravimetric analysis in air at a heating rate of 15 K min −1 . The Maceral Group concentrates were prepared by density separation of demineralized, micronized coal samples. Particle size had a significant effect on combustion profiles, with increased complexity in terms of the number of peaks observed for micronized coal compared with larger size fractions. Analysis of the combustion profiles of Macerals and reconstructed whole coals indicated that in some cases Maceral interactions can occur, especially in the presence of liptinite. It was also found that the reactivity of a coal cannot be predicted from the reactivities of its Maceral components.
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the inherent heterogeneity within the vitrinite Maceral Group
Fuel, 1994Co-Authors: David F Bensley, John C CrellingAbstract:Abstract Research has been directed towards the characterization of ultra-fine coal. Equipment and procedures have been developed which permit full reflectance characterization on vitrinite particles as small as 1.5 μm diameter using rotational polarization techniques. The application of this technology towards the evaluation of vitrinite Macerals separated using density gradient centrifugation has provided insights into the inherent heterogeneity of the vitrinite Maceral Group. It is concluded that much of the scatter in reflectance values obtained for a given coal is due to the presence of remnant cell structure. This structure cannot only be observed through etching, but can be directly measured using reflectance. Density gradient centrifugation can be used to separate and concentrate these remanent structures in high volatile bituminous vitrinite, provided the sample has been crushed to 5 μm or less. Within this rank range there is a strong trend towards increased reflectance with increasing vitrinite density.
A. C. Cook - One of the best experts on this subject based on the ideXlab platform.
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petroleum source rock assessment in non marine sequences pyrolysis and petrographic analysis of australian coals and carbonaceous shales
Organic Geochemistry, 1991Co-Authors: T. G. Powell, Nigel J Russell, M Smyth, Christopher J Boreham, A. C. CookAbstract:Abstract A series of Australian coals and terrestrial sediments ranging in age from Permian through tertiary have been analyzed to assess their petroleum source character and the suitability of various techniques for assessment of source rock potential in non-marine sequences. The procedures used include organic petrography, Rock-Eval pyrolysis, elemental analysis and quantitative pyrolysis-gas chromatography. The latter procedure was used to assess the potential yield of paraffins which is critical to the assessment of most non-marine source rocks. Principal components analysis was used to assist in the analysis of the data. Although the petroleum potential of the samples follows the broad trends in petrographic composition established for Australian coals, i.e. relative proportions of vitrinite, inertinite and liptinite, there is much variation which cannot be explained petrographically at the Maceral Group level. Further, pyrolytic hydrocarbon yield is not related to overall elemental composition below an atomic H/C ratio of 1.0. The yield of phenols in flash pyrolysis is related to depositional setting as well as degree of maturation. The yield and carbon number distribution of normal hydrocarbons in flash pyrolysis varied widely depending on the age, nature and amount of liptinite Macerals particularly in samples with Hydrogen Indices below 300. Liptinite-poor (
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petroleum source rock assessment in non marine sequences pyrolysis and petrographic analysis of australian coals and carbonaceous shales
Organic Geochemistry, 1991Co-Authors: T. G. Powell, Nigel J Russell, M Smyth, C J Oreham, A. C. CookAbstract:A series of Australian coals and terrestrial sediments ranging in age from Permian through tertiary have been analyzed to assess their petroleum source character and the suitability of various techniques for assessment of source rock potential in non-marine sequences. The procedures used include organic petrography, Rock-Eval pyrolysis, elemental analysis and quantitative pyrolysis-gas chromatography. The latter procedure was used to assess the potential yield of paraffins which is critical to the assessment of most non-marine source rocks. Principal components analysis was used to assist in the analysis of the data. Although the petroleum potential of the samples follows the broad trends in petrographic composition established for Australian coals, i.e. relative proportions of vitrinite, inertinite and liptinite, there is much variation which cannot be explained petrographically at the Maceral Group level. Further, pyrolytic hydrocarbon yield is not related to overall elemental composition below an atomic H/C ratio of 1.0. The yield of phenols in flash pyrolysis is related to depositional setting as well as degree of maturation. The yield and carbon number distribution of normal hydrocarbons in flash pyrolysis varied widely depending on the age, nature and amount of liptinite Macerals particularly in samples with Hydrogen Indices below 300. Liptinite-poor (< 10%) samples may yield significant amounts of hydrocarbons, but typically they have a low wax content. Sporinite-rich and liptodetrinite-rich samples give lower yields of normal hydrocarbons. These are predominantly of lower molecular weight. Suberinite and to a lesser extent cutinite are associated with high yields of waxy normal hydrocarbons, but some samples with high yields did not contain large amounts of these Maceral. The correlation of Tmax to vitrinite reflectance varies with petrographic composition. The results have implications for the way source rock analyses are conducted and interpreted in non-marine sequences.
John R. Bunt - One of the best experts on this subject based on the ideXlab platform.
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the impact of particle size and Maceral segregation on char formation in a packed bed combustion unit
Fuel, 2013Co-Authors: N Malumbazo, John R. Bunt, Nicola J WagnerAbstract:Abstract Highveld parent coal was crushed into three size fractions, namely: 5 mm–75 mm, 5 mm–53 mm, and 5–37.5 mm. The crushed samples were subjected as feed coals to heating in a packed-bed reactor to investigate the influence of particle size reduction on char formation and reactivity. Coal petrography was utilized to assess the Maceral and char formation distribution of the feed coal samples and their packed-bed combustion unit’s products. The Maceral distribution of the feed coal fractions differed from the typical run-of-mine Highveld coal petrographic composition; the smallest size fractions (−53 mm and −37.5 mm) having the highest vitrinite content. Maceral distribution was further divided into total reactive Maceral particles, total inert Maceral particles, and total inertinite particles. The −53 mm and −37.5 mm feed coal samples had the highest total reactive Maceral particle content. Inert char particles dominated in the packed-bed combustion unit samples due to high inertinite Maceral Group content of the Highveld coals. Unexpectedly, the −53 mm feed coal sample had higher content of total reactive Maceral particles and lower content of total inert Maceral particles; whereas the −37.5 mm feed coal sample had high content of reactive Maceral particles and high content of total inert Maceral particles. This variation in Maceral Group content lead to the −53 mm feed coal sample being more reactive (producing more devolatilized and porous chars and thus reacting faster with reactant gases) than the −37.5 mm feed coal sample. This was due to inert Maceral particles restricting the −37.5 mm feed coal sample from fully softening and reacting with reactant gas. This was also this was attributed to variation in volatile propagation of the three particle sizes. This confirms that a feed coal with smaller particle sizes results in different reactivity, char formation, and better heat transfer during combustion than the feed coal with large particle size range. Another important factor that plays a role in combustion is Maceral association; it was observed that Maceral distribution has a great influence on the char formation and its reactivity more than coal particle size.
T. G. Powell - One of the best experts on this subject based on the ideXlab platform.
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petroleum source rock assessment in non marine sequences pyrolysis and petrographic analysis of australian coals and carbonaceous shales
Organic Geochemistry, 1991Co-Authors: T. G. Powell, Nigel J Russell, M Smyth, Christopher J Boreham, A. C. CookAbstract:Abstract A series of Australian coals and terrestrial sediments ranging in age from Permian through tertiary have been analyzed to assess their petroleum source character and the suitability of various techniques for assessment of source rock potential in non-marine sequences. The procedures used include organic petrography, Rock-Eval pyrolysis, elemental analysis and quantitative pyrolysis-gas chromatography. The latter procedure was used to assess the potential yield of paraffins which is critical to the assessment of most non-marine source rocks. Principal components analysis was used to assist in the analysis of the data. Although the petroleum potential of the samples follows the broad trends in petrographic composition established for Australian coals, i.e. relative proportions of vitrinite, inertinite and liptinite, there is much variation which cannot be explained petrographically at the Maceral Group level. Further, pyrolytic hydrocarbon yield is not related to overall elemental composition below an atomic H/C ratio of 1.0. The yield of phenols in flash pyrolysis is related to depositional setting as well as degree of maturation. The yield and carbon number distribution of normal hydrocarbons in flash pyrolysis varied widely depending on the age, nature and amount of liptinite Macerals particularly in samples with Hydrogen Indices below 300. Liptinite-poor (
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petroleum source rock assessment in non marine sequences pyrolysis and petrographic analysis of australian coals and carbonaceous shales
Organic Geochemistry, 1991Co-Authors: T. G. Powell, Nigel J Russell, M Smyth, C J Oreham, A. C. CookAbstract:A series of Australian coals and terrestrial sediments ranging in age from Permian through tertiary have been analyzed to assess their petroleum source character and the suitability of various techniques for assessment of source rock potential in non-marine sequences. The procedures used include organic petrography, Rock-Eval pyrolysis, elemental analysis and quantitative pyrolysis-gas chromatography. The latter procedure was used to assess the potential yield of paraffins which is critical to the assessment of most non-marine source rocks. Principal components analysis was used to assist in the analysis of the data. Although the petroleum potential of the samples follows the broad trends in petrographic composition established for Australian coals, i.e. relative proportions of vitrinite, inertinite and liptinite, there is much variation which cannot be explained petrographically at the Maceral Group level. Further, pyrolytic hydrocarbon yield is not related to overall elemental composition below an atomic H/C ratio of 1.0. The yield of phenols in flash pyrolysis is related to depositional setting as well as degree of maturation. The yield and carbon number distribution of normal hydrocarbons in flash pyrolysis varied widely depending on the age, nature and amount of liptinite Macerals particularly in samples with Hydrogen Indices below 300. Liptinite-poor (< 10%) samples may yield significant amounts of hydrocarbons, but typically they have a low wax content. Sporinite-rich and liptodetrinite-rich samples give lower yields of normal hydrocarbons. These are predominantly of lower molecular weight. Suberinite and to a lesser extent cutinite are associated with high yields of waxy normal hydrocarbons, but some samples with high yields did not contain large amounts of these Maceral. The correlation of Tmax to vitrinite reflectance varies with petrographic composition. The results have implications for the way source rock analyses are conducted and interpreted in non-marine sequences.
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petroleum generation and source rock assessment in terrigenous sequences an update
The APPEA Journal, 1991Co-Authors: T. G. Powell, Christopher J BorehamAbstract:Analytical pyrolysis and sealed tube pyrolysis at low temperatures have been used to study the timing and petroleum generating capacity of selected Permian through Tertiary coals and carbonaceous shales in relation to their petrographic and elemental composition. The results show that judicious application of flash pyrolysis techniques in conjunction with more conventional procedures are essential for effective source rock assessment in terrigenous source rocks, particularly in those of lower quality. Although the petroleum potential of the samples follows the broad trends in petrographic composition established for Australian coals, that is, relative proportions of vitrinite, inertinite and liptinite, there is much variation which cannot be explained petrographically at the Maceral Group level. Furthermore, there is no simple relationship between pyrolytic hydrocarbon yield from terrigenous kerogens and overall elemental composition. The yield and composition of pyrolysable normal hydrocarbons varies widely depending on the nature and amount of liptinite Macerals, particularly for samples with Hydrogen Indices below 300. Liptinite-poor (<10 per cent) samples may yield significant amounts of hydrocarbons, but typically they have a low wax content. Suberinite is associated with high yields of waxy hydrocarbons, but sporinite and liptodetrinite have a lower hydrocarbon potential and do not yield the waxy compounds. These geochemical results are explicable in terms of the relatively abstract concepts of labile, refractory and inert kerogens rather than standard petrographic descriptions. Mass balance calculations based on Rock-Eval analyses of samples from the Jurassic Walloon Coal Measures show that the maximum oil formation occurs over a very narrow maturation window from 0.8 to 1.0 per cent Ro, although small amounts of oil may be generated at lower maturation levels. The gas to oil ratio of the generated hydrocarbons is constant up to a reflectance level of 1.0 per cent Ro, where upon the proportion of gas increases rapidly. The low quality Permian source rocks from the Cooper Basin have a lower ratio of labile to refractory kerogen than the Jurassic and Tertiary examples. As a result, the gas to oil ratio of hydrocarbons formed in the oil window is higher and the oil potential appears to be exhausted at an earlier stage of maturation. Efficient migration of hydrocarbons from Permian sediments in the Cooper Basin also appears to occur at a relatively early stage of maturation compared with the Jurassic Walloon Coal Measures.
