On the identification and origin of pseudovitrinite

Kaegi, D.D.

doi:10.1016/0166-5162(85)90017-5

Cited by 28 publications

(7 citation statements)

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“…During recycling, exposure to oxidation for variable durations progressively changes vitrinite into inertinite-like material which does not obey the same kinetic laws as indigenous vitrinite. This assumption is consistent with observations of Kaegi (1985) who noted that low-temperature oxidation converts pseudovitrinite into oxyvitrinite which is practically inertinite debris. Later, Bustin and Guo (1999) suggested that vitrinite and inertinite particles affected by the same thermal conditions show a subparallel increase in reflectance.…”

Section: Discussionsupporting

confidence: 81%

06/00519 Vitrinite recycling: diagnostic criteria andreflectance changes during weathering and reburial

2006

Fuel and Energy Abstracts

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The aim of this study was first to review or even identify reliable diagnostic criteria to distinguish recycled and autochthonous vitrinite particles and, second, to examine and try to explain the impact of weathering and reburial on optical changes (reflectance) of recycled material. The work was based on indigenous and recycled particles of two sample sets from two wells drilled in the Senegalese margin basin and the Ardèche paleomargin (SE France), respectively. In addition to reflectance measurements, the studied samples have also been analysed by Rock-Eval pyrolysis. For both sample sets, hydrogen index (HI) and oxygen index (OI) values suggest a type III organic matter of dominant terrestrial origin.Two main diagnostic criteria appear particularly useful to identify indigenous and recycled vitrinite particles: the first is the clear genetic relationship between telinite and collotelinite; the second is the presence of pyrite framboid inclusions in indigenous vitrinite. The pyrite-vitrinite association illustrates the relationship between sulphate reduction, pyritisation, and in situ organic matter transformation through gelification process. However, application of both diagnostic criteria requires some additional information about depositional conditions (i.e., anoxicity) and thermal maturity of the studied samples. Weathering has no or only very limited effect on vitrinite reflectance. During their new burial history, recycled vitrinites follow a reflectance evolution path close to that of inertinites and thus appear as transitional materials between vitrinite and inertinite macerals. Consistently, this behaviour implies that recycled vitrinite reflectance changes during burial diagenesis do not solely depend on their chemical composition but, most probably too, on combined chemical and structural changes inherited from their past burial history and from the impact of weathering during their recycling stage.

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Section: Discussionsupporting

confidence: 81%

06/00519 Vitrinite recycling: diagnostic criteria andreflectance changes during weathering and reburial

2006

Fuel and Energy Abstracts

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“…Benedict et al, 1968a,b;Gray, 1982;Kaegi, 1985;Kruszewska, 1998). It is a common maceral in the Svalbard coal.…”

Section: Properties Common To Both Seamsmentioning

confidence: 95%

Petrography and geochemical affinities of Spitsbergen Paleocene coals, Norway

Orheim¹,

Bieg²,

Brekke³

et al. 2007

International Journal of Coal Geology

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“…Pseudovitrinite does not usually fluoresce under ultraviolet excitation, and its reflectance is slightly higher than that of normal vitrinite (Stach et al, 1982). Kaegi (1985) was able to form pseudovitrinite by desiccation when heating a coal sample to 50 ı C, arguing that oxidation is not required for the formation of pseudovitrinite. Stach et al (1982) attributed its formation to gel desiccation and shrinkage in the early maturation stages, while Lamberson and Bustin (1993) stated that neither of the above processes adequately explained the presence of pseudovitrinite in the Cretaceous-age Gates coals of northeastern British Columbia.…”

Section: Introductionmentioning

confidence: 91%

Does the Presence of Pseudovitrinite Indicate Gas-saturated Coals? Some Interesting Observations from the Gething Coals in Canada

Gentzis¹

2008

Energy Sources, Part A: Recovery, Utilization, and Environmenta

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The presence of pseudovitrinite at a depth of 1,000 m in the very gassy (up to 862 scf/ton total gas content, as-received basis) but low absolute permeability (0.5 mD), low-volatile bituminous Gething coals in the Canadian Foothills has been documented. Because oxidation is unlikely to occur at such depth, it is reasonable to expect that pseudovitrinite formed as a result of desiccation in a gas-saturated environment prior to the coals being uplifted to their present day depth. This raises the possibility that a coal that contains pseudovitrinite may have moisture content that is below its equilibrium moisture, which leads to higher methane adsorptive capacity compared with the same coal that has "normal" vitrinite (collotelinite). The presence of inertinite macerals in the coal, derived from wood fibers and charred remnants, has aided in the development and preservation of phyteral porosity and in the formation of interconnected microcavities, which should result in higher micropermeability and aid the flow of gas locally within the coal seam and surrounding strata. The Gething coals in the Highhat corehole share some of these characteristics, which may have important implications on the dynamics of coal-bed methane production. Volumetric strain (matrix shrinkage) of these gassy coals during production is conservatively estimated to be 0.5-0.75%, which may result in an absolute permeability increase of between 5 to 12 times, based on studies on coals of similar rank and gas content in United States basins. Although observations made in this preliminary study do not constitute a proof, they leave open the possibility of using pseudovitrinite, under certain circumstances, as an indicator of improved gas sorptive capacity and enhanced permeability in deep coals.

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On the identification and origin of pseudovitrinite

Cited by 28 publications

References 0 publications

06/00519 Vitrinite recycling: diagnostic criteria andreflectance changes during weathering and reburial

06/00519 Vitrinite recycling: diagnostic criteria andreflectance changes during weathering and reburial

Petrography and geochemical affinities of Spitsbergen Paleocene coals, Norway

Does the Presence of Pseudovitrinite Indicate Gas-saturated Coals? Some Interesting Observations from the Gething Coals in Canada

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