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Paul C. Hackley - One of the best experts on this subject based on the ideXlab platform.
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Sample mounting for Organic Petrology: No thermal effects from transient exposure to elevated temperatures
International Journal of Coal Geology, 2020Co-Authors: Paul C. Hackley, Brian J. CardottAbstract:Abstract For sample mounting, Organic Petrology laboratories typically use cold-setting epoxy-resin (e.g., 40 °C, used by Oklahoma Geological Survey, OGS) or heat-setting thermoplastic (e.g., 180 °C, used by U.S. Geological Survey, USGS). Previous workers have suggested a systematic huminite/vitrinite reflectance (VRo) increase was associated with the thermoplastic preparation process, relative to epoxy mounting, which was possibly attributed to moisture loss from Organic matter due to the transient high temperatures of plastic mounting. In this study, we evaluated thermal effects to low thermal maturity Organic matter from transient exposure to elevated temperatures. A subbituminous coal sample was subjected to long-term (4 to 38 weeks) exposure to temperatures of 85 to 120 °C and afterward evaluated by multiple approaches to test thermal advance [elemental analyses, Rock-Eval pyrolysis, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), pyrolysis gas chromatography, and petrographic analyses, including huminite/vitrinite reflectance and spectral fluorescence], all of which showed no detectable systematic (statistically insignificant) changes between the original sample and its heat-treated products. We also compared huminite/vitrinite reflectance of six low thermal maturity samples (those most likely to react to transient heating) mounted via both cold-setting epoxy-resin and heat-setting thermoplastic. Results indicate measured VRo of a sample prepared by one mounting process was within the standard deviation of reflectance for the same sample prepared via the other process. Moreover, VRo results were not systematically higher in thermoplastic mounts. Contrary to previous work, these results suggest thermoplastic mounting or other transient exposure to elevated temperatures does not impact thermal maturity estimates from reflectance measurement for low thermal maturity Organic samples. Furthermore, the average interlaboratory difference in measured VRo (between OGS and USGS) for the same sample prepared by either epoxy-resin or thermoplastic mounting was 0.038%, about double the average difference between VRo for the same sample prepared via epoxy-resin versus thermoplastic in a single laboratory (0.024%). This result indicates interlaboratory variability impacts VRo measurement reproducibility to the extent that systematic differences could not be observed between thermoplastic and cold-setting sample preparation approaches, even if such differences were present.
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pore types and pore network evolution in upper devonian lower mississippian woodford and mississippian barnett mudstones insights from laboratory thermal maturation and Organic Petrology
International Journal of Coal Geology, 2017Co-Authors: Lucy T Ko, Paul C. Hackley, Robert G Loucks, Stephen C Ruppel, Tongwei Zhang, Deyong ShaoAbstract:Abstract Pore-evolution models from immature Organic-matter (OM) -rich Barnett (0.42%R o ) and Woodford (0.49%R o ) mudstones were compared with models previously developed from low-maturity OM-lean Boquillas (Eagle Ford-equivalent) mudstones to investigate whether (1) different mineralogy (siliceous vs. calcareous) exerts different catalytic and sorption effects and influences OM-pore origin and evolution; and (2) different types of macerals show different OM pore evolution history. Laboratory gold-tube pyrolysis, scanning electron microscopy (SEM) and thin-section petrography, Organic petrography, and geochemical characterization were used to investigate the role of bulk mineralogy, maceral type, and thermal maturation on OM-pore evolution. Results suggest that mineralogy has little impact on OM-pore development and evolution. Macerals, identified using both SEM (platy OM, particulate OM, Organic–mineral admixtures, Tasmanites ) and Organic Petrology (vitrinite, inertinite, amorphous Organic matter [AOM]/bituminite, telalginite [ Leiosphaeridia , Tasmanites ]), do affect the origin and evolution of OM pores owing to differences in chemical compositions, generation kinetics, and activation-energy distributions between Tasmanites , matrix bituminite, and other types of macerals. Leiosphaeridia and Tasmanites in Woodford mudstone samples exhibit a delay in onset and a shorter period of petroleum generation and pore development compared to the matrix bituminite in the Barnett and Woodford mudstone samples. Pre-oil solid bitumen was observed to have migrated into initial primary mineral pore networks at the bitumen generation stage in both Barnett and Woodford samples. At higher levels of thermal maturation, the volume of primary mineral pores decreases and the pore volume composed of modified mineral pores and OM pores becomes greater. Pore evolution and pore-type heterogeneity in these mudstones is a function of the initial mineral pore network, types of kerogen and macerals, and generation kinetics of individual macerals upon thermal maturation.
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pore types and pore network evolution in upper devonian lower mississippian woodford and mississippian barnett mudstones insights from laboratory thermal maturation and Organic Petrology
International Journal of Coal Geology, 2017Co-Authors: Stephen C Ruppel, Paul C. Hackley, Robert G Loucks, Tongwei Zhang, Deyong ShaoAbstract:Abstract Pore-evolution models from immature Organic-matter (OM) -rich Barnett (0.42%R o ) and Woodford (0.49%R o ) mudstones were compared with models previously developed from low-maturity OM-lean Boquillas (Eagle Ford-equivalent) mudstones to investigate whether (1) different mineralogy (siliceous vs. calcareous) exerts different catalytic and sorption effects and influences OM-pore origin and evolution; and (2) different types of macerals show different OM pore evolution history. Laboratory gold-tube pyrolysis, scanning electron microscopy (SEM) and thin-section petrography, Organic petrography, and geochemical characterization were used to investigate the role of bulk mineralogy, maceral type, and thermal maturation on OM-pore evolution. Results suggest that mineralogy has little impact on OM-pore development and evolution. Macerals, identified using both SEM (platy OM, particulate OM, Organic–mineral admixtures, Tasmanites ) and Organic Petrology (vitrinite, inertinite, amorphous Organic matter [AOM]/bituminite, telalginite [ Leiosphaeridia , Tasmanites ]), do affect the origin and evolution of OM pores owing to differences in chemical compositions, generation kinetics, and activation-energy distributions between Tasmanites , matrix bituminite, and other types of macerals. Leiosphaeridia and Tasmanites in Woodford mudstone samples exhibit a delay in onset and a shorter period of petroleum generation and pore development compared to the matrix bituminite in the Barnett and Woodford mudstone samples. Pre-oil solid bitumen was observed to have migrated into initial primary mineral pore networks at the bitumen generation stage in both Barnett and Woodford samples. At higher levels of thermal maturation, the volume of primary mineral pores decreases and the pore volume composed of modified mineral pores and OM pores becomes greater. Pore evolution and pore-type heterogeneity in these mudstones is a function of the initial mineral pore network, types of kerogen and macerals, and generation kinetics of individual macerals upon thermal maturation.
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Organic Petrology of peak oil maturity triassic yanchang formation lacustrine mudrocks ordos basin china
Interpretation, 2017Co-Authors: Paul C. Hackley, Lixia Zhang, Tongwei ZhangAbstract:AbstractAn Organic Petrology evaluation and a determination of solid bitumen reflectance BRo were completed for Organic-rich Triassic Yanchang Formation mudrocks (n=15) from the Ordos Basin, north-central China, as part of a larger investigation of “shale gas” resources. These data were integrated with information from Rock-Eval programmed pyrolysis to show that the samples are in the peak oil window of thermal maturity and that Organic matter is dominated by solid bitumen with minor amounts of type III kerogen (vitrinite and inertinite) from vascular land plants. Describing a “kerogen type” for these rocks based strictly on parameters determined from programmed pyrolysis is misleading because the original Organic matter has converted to hydrocarbons (present as solid bitumen), a large proportion of which may have been expelled into adjacent reservoir facies. However, based on the comparison with immature-early mature lacustrine mudrock (Garden Gulch Member of Green River Formation) and marine shale (Boqu...
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Organic Petrology and micro-spectroscopy of Tasmanites microfossils: Applications to kerogen transformations in the early oil window
Organic Geochemistry, 2017Co-Authors: Paul C. Hackley, Maria Mastalerz, Clifford C. Walters, Simon R. Kelemen, Heather A. LowersAbstract:Abstract The transformation of kerogen to hydrocarbons in the early stages of oil generation is critical for understanding the resource potential of liquid-rich shale plays. Organic Petrology commonly is used for visual evaluation of type, quality, and thermal maturity of Organic matter, but the relationship of visual petrographic changes to chemical transformations is not well characterized. To improve understanding of these processes, Organic-walled microfossils of the unicellular green alga Tasmanites (composed of algaenan) in Upper Devonian Ohio Shale (Huron Member, Appalachian Basin) were analyzed by micro-spectroscopy techniques including micro-Fourier transform infrared (micro-FTIR), X-ray photoelectron (XPS), electron probe microanalysis (EPMA), and fluorescence. Immature to mid-oil window maturation sequences of core and outcrop samples with solid bitumen reflectance (BR) and vitrinite reflectance (VR) values ranging from 0.45 to 0.80 %Ro were used. Hydrous pyrolysis was applied to low-maturity (BR: 0.25–0.39 %Ro) Huron and time-correlative New Albany shale samples to create similar artificial maturation sequences for comparison. Micro-FTIR spectroscopy revealed a decrease in the CH 2 /CH 3 ratio with increasing maturity, indicating Tasmanites aliphatic chains become shorter and more branched. Oxygenated functional groups decreased relative to aliphatic stretching bands and increased aromaticity was noted at the highest maturities. In samples that were pyrolyzed for 72 h at temperatures of 300–320 °C (BR: 0.56–0.68 %Ro), Tasmanites showed similar trends, whereas at pyrolysis temperatures of 340 °C and higher (BR > 1.0 %Ro), Tasmanites was pseudomorphed by accumulations of solid bitumen, carbonate and sulfide. Replacement of Tasmanites by these phases in hydrous pyrolysis experiments ≥340 °C and its absence at higher maturities (peak oil, VR and BR ≥ 0.9 %Ro) in naturally matured samples, as documented in a previous study, implies that a large fraction of the algaenan component of original Organic carbon is converted to petroleum during thermal maturation. XPS analysis indicated the molar proportion of aliphatic carbon increases with increasing thermal maturity, accompanied by decreases in oxygenated functional groups and olefinic carbon. EPMA of Tasmanites showed highest concentrations of S, with concentrations of redox-sensitive trace elements U, Mo, Ni and V generally at or below detection limits. Decrease in Organic S with increasing thermal maturity may be related to cleavage of Tasmanites at C S linkages; however, this relationship was inconsistent and presence of adjacent or entrained nanoscale silicate or sulfide phases may impact measured trace element concentrations. Fluorescence microscopy and spectroscopy showed a red shift in spectral maxima and decreased emission intensities with increasing maturity, interpreted as due to non-radiative energy loss possibly because of increased aromaticity. Collectively, these results provide new insights into the in situ chemical transformations that accompany petrographic changes as oil-prone kerogen converts to petroleum with thermal advance from immature conditions into the mid-oil window.
V.p. Chabalala - One of the best experts on this subject based on the ideXlab platform.
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geochemistry and Organic Petrology of the permian whitehill formation karoo basin rsa and the devonian carboniferous shale of the appalachian basin usa
International Journal of Coal Geology, 2020Co-Authors: V.p. Chabalala, Nicola J. Wagner, N. Malumbazo, C.f. EbleAbstract:Abstract Globally, there is significant economic interest in shale gas as a hydrocarbon resource. The success of unconventional shale gas exploration in the United State of America (USA) has raised interests for potential shale gas development in the Karoo Basin of South Africa. The Karoo Basin technically recoverable shale gas resource is estimated to be 13 Tcf, with 19–23 Tcf recoverable free gas. Due to the potential importance of the South African resource, this study characterized the Lower Permian Ecca Group shale and compared its geochemical and Organic Petrology properties with those of Devonian/Carboniferous shales of the Appalachian Basin, USA. The comparison of research data will aid in the understanding of shale gas potential of the Karoo Basin. Horizons from two boreholes (KZF-01 and KWV-01) drilled in the southern and southeastern Karoo Basin were evaluated and compared with samples of the Late Devonian Ohio and Early Carboniferous Sunbury Shales from the central Appalachian Basin, USA. Total Organic carbon (TOC), total sulphur (TS), and Organic Petrology (bitumen and vitrinite reflectance, and maceral analysis) were used to assess Organic richness and thermal maturity of the shale samples. In addition, the samples were evaluated for mineralogical content using X-Ray Diffraction (XRD). Data indicates that the Whitehill Formation of the Karoo Basin has good to excellent shale source potential, with an average TOC of 4.35 wt%. However, thermal maturity data of the Whitehill Formation shows the Organic matter to be overmature, with vitrinite reflectance equivalent values greater than 3% RoV. Total sulphur data for the Whitehill Formation and the Devonian/Carboniferous shales suggests that both were influenced by marine environments. Both the KWV-01 and Ohio/Sunbury shale samples contain high amounts of quartz, with clay mineral contents greater than 40% being observed in borehole KWV-01 samples. Collectively, this research study provides valuable data for shale gas exploration and development in the Karoo Basin, South Africa.
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Geochemistry and Organic Petrology of the permian whitehill formation, Karoo Basin (RSA) and the Devonian/Carboniferous shale of the Appalachian Basin (USA)
International Journal of Coal Geology, 2020Co-Authors: V.p. Chabalala, Nicola J. Wagner, N. Malumbazo, C.f. EbleAbstract:Abstract Globally, there is significant economic interest in shale gas as a hydrocarbon resource. The success of unconventional shale gas exploration in the United State of America (USA) has raised interests for potential shale gas development in the Karoo Basin of South Africa. The Karoo Basin technically recoverable shale gas resource is estimated to be 13 Tcf, with 19–23 Tcf recoverable free gas. Due to the potential importance of the South African resource, this study characterized the Lower Permian Ecca Group shale and compared its geochemical and Organic Petrology properties with those of Devonian/Carboniferous shales of the Appalachian Basin, USA. The comparison of research data will aid in the understanding of shale gas potential of the Karoo Basin. Horizons from two boreholes (KZF-01 and KWV-01) drilled in the southern and southeastern Karoo Basin were evaluated and compared with samples of the Late Devonian Ohio and Early Carboniferous Sunbury Shales from the central Appalachian Basin, USA. Total Organic carbon (TOC), total sulphur (TS), and Organic Petrology (bitumen and vitrinite reflectance, and maceral analysis) were used to assess Organic richness and thermal maturity of the shale samples. In addition, the samples were evaluated for mineralogical content using X-Ray Diffraction (XRD). Data indicates that the Whitehill Formation of the Karoo Basin has good to excellent shale source potential, with an average TOC of 4.35 wt%. However, thermal maturity data of the Whitehill Formation shows the Organic matter to be overmature, with vitrinite reflectance equivalent values greater than 3% RoV. Total sulphur data for the Whitehill Formation and the Devonian/Carboniferous shales suggests that both were influenced by marine environments. Both the KWV-01 and Ohio/Sunbury shale samples contain high amounts of quartz, with clay mineral contents greater than 40% being observed in borehole KWV-01 samples. Collectively, this research study provides valuable data for shale gas exploration and development in the Karoo Basin, South Africa.
C.f. Eble - One of the best experts on this subject based on the ideXlab platform.
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geochemistry and Organic Petrology of the permian whitehill formation karoo basin rsa and the devonian carboniferous shale of the appalachian basin usa
International Journal of Coal Geology, 2020Co-Authors: V.p. Chabalala, Nicola J. Wagner, N. Malumbazo, C.f. EbleAbstract:Abstract Globally, there is significant economic interest in shale gas as a hydrocarbon resource. The success of unconventional shale gas exploration in the United State of America (USA) has raised interests for potential shale gas development in the Karoo Basin of South Africa. The Karoo Basin technically recoverable shale gas resource is estimated to be 13 Tcf, with 19–23 Tcf recoverable free gas. Due to the potential importance of the South African resource, this study characterized the Lower Permian Ecca Group shale and compared its geochemical and Organic Petrology properties with those of Devonian/Carboniferous shales of the Appalachian Basin, USA. The comparison of research data will aid in the understanding of shale gas potential of the Karoo Basin. Horizons from two boreholes (KZF-01 and KWV-01) drilled in the southern and southeastern Karoo Basin were evaluated and compared with samples of the Late Devonian Ohio and Early Carboniferous Sunbury Shales from the central Appalachian Basin, USA. Total Organic carbon (TOC), total sulphur (TS), and Organic Petrology (bitumen and vitrinite reflectance, and maceral analysis) were used to assess Organic richness and thermal maturity of the shale samples. In addition, the samples were evaluated for mineralogical content using X-Ray Diffraction (XRD). Data indicates that the Whitehill Formation of the Karoo Basin has good to excellent shale source potential, with an average TOC of 4.35 wt%. However, thermal maturity data of the Whitehill Formation shows the Organic matter to be overmature, with vitrinite reflectance equivalent values greater than 3% RoV. Total sulphur data for the Whitehill Formation and the Devonian/Carboniferous shales suggests that both were influenced by marine environments. Both the KWV-01 and Ohio/Sunbury shale samples contain high amounts of quartz, with clay mineral contents greater than 40% being observed in borehole KWV-01 samples. Collectively, this research study provides valuable data for shale gas exploration and development in the Karoo Basin, South Africa.
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Geochemistry and Organic Petrology of the permian whitehill formation, Karoo Basin (RSA) and the Devonian/Carboniferous shale of the Appalachian Basin (USA)
International Journal of Coal Geology, 2020Co-Authors: V.p. Chabalala, Nicola J. Wagner, N. Malumbazo, C.f. EbleAbstract:Abstract Globally, there is significant economic interest in shale gas as a hydrocarbon resource. The success of unconventional shale gas exploration in the United State of America (USA) has raised interests for potential shale gas development in the Karoo Basin of South Africa. The Karoo Basin technically recoverable shale gas resource is estimated to be 13 Tcf, with 19–23 Tcf recoverable free gas. Due to the potential importance of the South African resource, this study characterized the Lower Permian Ecca Group shale and compared its geochemical and Organic Petrology properties with those of Devonian/Carboniferous shales of the Appalachian Basin, USA. The comparison of research data will aid in the understanding of shale gas potential of the Karoo Basin. Horizons from two boreholes (KZF-01 and KWV-01) drilled in the southern and southeastern Karoo Basin were evaluated and compared with samples of the Late Devonian Ohio and Early Carboniferous Sunbury Shales from the central Appalachian Basin, USA. Total Organic carbon (TOC), total sulphur (TS), and Organic Petrology (bitumen and vitrinite reflectance, and maceral analysis) were used to assess Organic richness and thermal maturity of the shale samples. In addition, the samples were evaluated for mineralogical content using X-Ray Diffraction (XRD). Data indicates that the Whitehill Formation of the Karoo Basin has good to excellent shale source potential, with an average TOC of 4.35 wt%. However, thermal maturity data of the Whitehill Formation shows the Organic matter to be overmature, with vitrinite reflectance equivalent values greater than 3% RoV. Total sulphur data for the Whitehill Formation and the Devonian/Carboniferous shales suggests that both were influenced by marine environments. Both the KWV-01 and Ohio/Sunbury shale samples contain high amounts of quartz, with clay mineral contents greater than 40% being observed in borehole KWV-01 samples. Collectively, this research study provides valuable data for shale gas exploration and development in the Karoo Basin, South Africa.
Deolinda Flores - One of the best experts on this subject based on the ideXlab platform.
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Study of a Silurian sequence of Dornes region (Central Iberian Zone, Portugal): The contribution of Organic Petrology and palynofacies
International Journal of Coal Geology, 2020Co-Authors: Paula Alexandra Gonçalves, João Graciano Mendonça Filho, Sérgio Pinheiro, Joalice De Oliveira Mendonça, Deolinda FloresAbstract:Abstract A Wenlock (Silurian) sedimentary continuous sequence was sampled in the Dornes region (Central Iberian Zone, Portugal) to characterize the Organic matter type using different microscopic analyses (Organic Petrology and palynofacies). Total Organic carbon (TOC) was also determined. Samples are part of Foz da Serta Formation and correspond to mudstone, punctually with sandstone, rich in Organic matter (mean TOC value of 5.1%). Whole rock samples showed a dominance of non-granular graptolites (lath- and blocky-shape) and solid bitumen. Lath-shape graptolites display the characteristic segmented structure. In the blocky-shape graptolites, the fusellar layers of the graptolite wall are well marked and are an important distinctive feature. Foz da Serta graptolites are optically anisotropic as well as the solid bitumen. Non-granular graptolite's maximum reflectance varies from 1.43 to 3.94% and solid bitumen maximum reflectance oscillates between 1.09 and 2.22%. Vitrinite reflectance equivalent was calculated using Bertrand and Malo's equation (values between 1.97 and 3.72%) denoting a post-mature stage for the Organic matter. No relation was established with confidence between graptolite maximum reflectance and solid bitumen maximum reflectance. The palynofacies study confirmed not only the presence of graptolite and solid bitumen but also amorphous material derived from graptolite. Under transmitted white light, graptolite features were not noticed. To improve the palynofacies characterization, reflected white light was used on slides, thus exposing distinctive graptolite features. The different lights and preparation types used allowed a better characterization of the Organic matter present in Foz da Serta Formation samples, mainly the graptolites. The use of reflected white light, in the palynofacies study, proved to be extremely important in the description of the graptolite features.
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Review and update of the applications of Organic Petrology: Part 1, geological applications
International Journal of Coal Geology, 2012Co-Authors: Isabel Suárez-ruiz, Deolinda Flores, João Graciano Mendonça Filho, Paul C. HackleyAbstract:Abstract Organic Petrology developed as coal Petrology at the beginning of the 20th century dedicated mainly to the study of coals because of their utilization in industry. Coal Petrology was then considered a branch of coal science. Later, with the development of specialized nomenclature, classification of coal components, and the standardization and improvement of analytical (microscopical) methods, this discipline expanded in interests and name, becoming Organic Petrology. Organic Petrology carries a broader context, being as well a tool applied in the study of dispersed Organic matter in sedimentary rocks due to its importance in exploration for fossil fuel resources. At present, Organic Petrology is a discipline widely recognized for its role in fundamental and applied research with respect to both coal utilization and in geosciences. Throughout the 20th century several important monographs have been published on the discipline of Organic Petrology, including “Stach's textbook of coal Petrology” (1st edition 1935, 2nd 1975, 3rd 1982), updated as the more general “Organic Petrology” by Taylor et al. (1998). More recently, the text “Applied coal Petrology: the role of Petrology in coal utilization” was published by Suarez-Ruiz and Crelling (2008). This review is the first in a two-part review series that describes and updates the role of Organic Petrology in geosciences. A second part complementing this one and focused on the applications of Organic Petrology to other scientific fields will follow.
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Review and update of the applications of Organic Petrology; Part 2, Geological and multidisciplinary applications
International Journal of Coal Geology, 2012Co-Authors: Isabel Suárez-ruiz, Deolinda Flores, João Graciano Mendonça Filho, Paul C. HackleyAbstract:Abstract The present paper is focused on Organic Petrology applied to unconventional and multidisciplinary investigations and is the second part of a two part review that describes the geological applications and uses of this branch of earth sciences. Therefore, this paper reviews the use of Organic Petrology in investigations of: (i) ore genesis when Organic matter occurs associated with mineralization; (ii) the behavior of Organic matter in coal fires (self-heating and self-combustion); (iii) environmental and anthropogenic impacts associated with the management and industrial utilization of coal; (iv) archeology and the nature and geographical provenance of objects of Organic nature such as jet, amber, other artifacts and coal from archeological sites; and (v) forensic science connected with criminal behavior or disasters. This second part of the review outlines the most recent research and applications of Organic Petrology in those fields.
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the procedure used to develop a coal char classification commission iii combustion working group of the international committee for coal and Organic Petrology
International Journal of Coal Geology, 2010Co-Authors: Edward Lester, Deolinda Flores, Diego Alvarez, A G Borrego, Bruno Valentim, D Clift, Per Rosenberg, Barbara Kwiecinska, Richelieu Barranco, H I PetersenAbstract:Abstract This paper describes an assessment of char classification system by the Combustion Working Group in Commission III of the International Committee for Coal and Organic Petrology (ICCP). The work of the group culminated in the production of a char atlas after a final round robin exercise. This round robin involved 21 analysts and was an electronic exercise using digitally captured images of individual char particles, rather than actual char blocks. A software program featuring 170 char images was specifically designed to allow operators to identify each char based on a classification system with 9 individual char types; tenuisphere, crassisphere, tenuinetwork, crassinetwork, mixed porous, mixed dense, fusinoid, solid and mineroid. The program electronically recorded all decisions as well as the time taken for each decision to be made. From 170 chars, 128 chars were identified by a majority (> 70%) and these chars were then compiled in a char atlas that is now available for download ( www.nottingham.ac.uk/~eczehl/charatlas ). As would be expected all analysts appeared to become more confident in identifying chars during the exercise, taking less time per image, but with no clear evidence of improvement. Without exception, analysts took longer to make an incorrect decision.
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The procedure used to develop a coal char classification—Commission III Combustion Working Group of the International Committee for Coal and Organic Petrology
International Journal of Coal Geology, 2010Co-Authors: Edward Lester, Deolinda Flores, Diego Alvarez, A G Borrego, Bruno Valentim, Per Rosenberg, Barbara Kwiecinska, Richelieu Barranco, D.a. Clift, H I PetersenAbstract:Abstract This paper describes an assessment of char classification system by the Combustion Working Group in Commission III of the International Committee for Coal and Organic Petrology (ICCP). The work of the group culminated in the production of a char atlas after a final round robin exercise. This round robin involved 21 analysts and was an electronic exercise using digitally captured images of individual char particles, rather than actual char blocks. A software program featuring 170 char images was specifically designed to allow operators to identify each char based on a classification system with 9 individual char types; tenuisphere, crassisphere, tenuinetwork, crassinetwork, mixed porous, mixed dense, fusinoid, solid and mineroid. The program electronically recorded all decisions as well as the time taken for each decision to be made. From 170 chars, 128 chars were identified by a majority (> 70%) and these chars were then compiled in a char atlas that is now available for download ( www.nottingham.ac.uk/~eczehl/charatlas ). As would be expected all analysts appeared to become more confident in identifying chars during the exercise, taking less time per image, but with no clear evidence of improvement. Without exception, analysts took longer to make an incorrect decision.
Deyong Shao - One of the best experts on this subject based on the ideXlab platform.
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pore types and pore network evolution in upper devonian lower mississippian woodford and mississippian barnett mudstones insights from laboratory thermal maturation and Organic Petrology
International Journal of Coal Geology, 2017Co-Authors: Lucy T Ko, Paul C. Hackley, Robert G Loucks, Stephen C Ruppel, Tongwei Zhang, Deyong ShaoAbstract:Abstract Pore-evolution models from immature Organic-matter (OM) -rich Barnett (0.42%R o ) and Woodford (0.49%R o ) mudstones were compared with models previously developed from low-maturity OM-lean Boquillas (Eagle Ford-equivalent) mudstones to investigate whether (1) different mineralogy (siliceous vs. calcareous) exerts different catalytic and sorption effects and influences OM-pore origin and evolution; and (2) different types of macerals show different OM pore evolution history. Laboratory gold-tube pyrolysis, scanning electron microscopy (SEM) and thin-section petrography, Organic petrography, and geochemical characterization were used to investigate the role of bulk mineralogy, maceral type, and thermal maturation on OM-pore evolution. Results suggest that mineralogy has little impact on OM-pore development and evolution. Macerals, identified using both SEM (platy OM, particulate OM, Organic–mineral admixtures, Tasmanites ) and Organic Petrology (vitrinite, inertinite, amorphous Organic matter [AOM]/bituminite, telalginite [ Leiosphaeridia , Tasmanites ]), do affect the origin and evolution of OM pores owing to differences in chemical compositions, generation kinetics, and activation-energy distributions between Tasmanites , matrix bituminite, and other types of macerals. Leiosphaeridia and Tasmanites in Woodford mudstone samples exhibit a delay in onset and a shorter period of petroleum generation and pore development compared to the matrix bituminite in the Barnett and Woodford mudstone samples. Pre-oil solid bitumen was observed to have migrated into initial primary mineral pore networks at the bitumen generation stage in both Barnett and Woodford samples. At higher levels of thermal maturation, the volume of primary mineral pores decreases and the pore volume composed of modified mineral pores and OM pores becomes greater. Pore evolution and pore-type heterogeneity in these mudstones is a function of the initial mineral pore network, types of kerogen and macerals, and generation kinetics of individual macerals upon thermal maturation.
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pore types and pore network evolution in upper devonian lower mississippian woodford and mississippian barnett mudstones insights from laboratory thermal maturation and Organic Petrology
International Journal of Coal Geology, 2017Co-Authors: Stephen C Ruppel, Paul C. Hackley, Robert G Loucks, Tongwei Zhang, Deyong ShaoAbstract:Abstract Pore-evolution models from immature Organic-matter (OM) -rich Barnett (0.42%R o ) and Woodford (0.49%R o ) mudstones were compared with models previously developed from low-maturity OM-lean Boquillas (Eagle Ford-equivalent) mudstones to investigate whether (1) different mineralogy (siliceous vs. calcareous) exerts different catalytic and sorption effects and influences OM-pore origin and evolution; and (2) different types of macerals show different OM pore evolution history. Laboratory gold-tube pyrolysis, scanning electron microscopy (SEM) and thin-section petrography, Organic petrography, and geochemical characterization were used to investigate the role of bulk mineralogy, maceral type, and thermal maturation on OM-pore evolution. Results suggest that mineralogy has little impact on OM-pore development and evolution. Macerals, identified using both SEM (platy OM, particulate OM, Organic–mineral admixtures, Tasmanites ) and Organic Petrology (vitrinite, inertinite, amorphous Organic matter [AOM]/bituminite, telalginite [ Leiosphaeridia , Tasmanites ]), do affect the origin and evolution of OM pores owing to differences in chemical compositions, generation kinetics, and activation-energy distributions between Tasmanites , matrix bituminite, and other types of macerals. Leiosphaeridia and Tasmanites in Woodford mudstone samples exhibit a delay in onset and a shorter period of petroleum generation and pore development compared to the matrix bituminite in the Barnett and Woodford mudstone samples. Pre-oil solid bitumen was observed to have migrated into initial primary mineral pore networks at the bitumen generation stage in both Barnett and Woodford samples. At higher levels of thermal maturation, the volume of primary mineral pores decreases and the pore volume composed of modified mineral pores and OM pores becomes greater. Pore evolution and pore-type heterogeneity in these mudstones is a function of the initial mineral pore network, types of kerogen and macerals, and generation kinetics of individual macerals upon thermal maturation.