Hydrous pyrolysis maturation of vitrinite-like and humic vitrinite macerals: Implications for thermal maturity analysis

Schmidt, Jaques Soares; Araujo, Carla Viviane; Souza, Igor Viegas Alves Fernandes de; Chagas, Renata Brenand A. das

doi:10.1016/j.coal.2015.03.016

Cited by 21 publications

(9 citation statements)

References 20 publications

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“…As mentioned earlier, previous workers have noted the occurrence of vitrinite-like macerals, which are interpreted as syndepositional because of sharp outlines, uniform reflectance, and absence of void filling or groundmass textures (Houseknecht and Matthews, 1985;Buchardt and Lewan, 1990;Xiao et al, 2000;Schmidt et al, 2015). Buchardt and Lewan (1990) did not like the mobility connotation that solid bitumen conveys in describing the vitrinite-like maceral observed in rock thin sections and isolated-kerogen epoxy mounts of the Alum Shale.…”

Section: Causes Of Vitrinite-reflectance Suppressionmentioning

confidence: 87%

Understanding and distinguishing reflectance measurements of solid bitumen and vitrinite using hydrous pyrolysis: Implications to petroleum assessment

Hackley

Lewan

2018

Bulletin

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Solid bitumen is a common organic component of thermally mature shales and typically is identified by embayment against euhedral mineral terminations and by groundmass textures. However, because these textures are not always present, solid bitumen can be easily misidentified as vitrinite. Hydrous-pyrolysis experiments (72 hr, 300°C-360°C) on shale and coal samples show that solid-bitumen reflectance (BR o) in shales is less responsive to thermal stress than vitrinite reflectance (R o) in coal. This effect is most pronounced at lower experimental temperatures (300°C-320°C), whereas reflectance changes are more similar at higher temperatures (340°C-360°C). Neither a "vitrinitelike" maceral nor "suppressed vitrinite" was identified or measured in our sample set; instead, the experiments show that solid bitumen matures slower than vitrinite. The data may explain some reports of "R o suppression," particularly at lower thermal maturity (R o £ 1.0%), as a simple case of solid bitumen being mistaken for vitrinite. Further, the experimental results confirm previous empirical observations that R o and BR o are more similar at higher maturities (R o > 1.0%). It is suggested that R o suppression, commonly reported from upper Paleozoic marine shales of early to midoil window maturity, is a misnomer. This observation has important implications to petroleum exploration models and resource assessment, because it may change interpretations for the timing and spatial locations of kerogen maturation and petroleum generation.

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Section: Causes Of Vitrinite-reflectance Suppressionmentioning

confidence: 87%

Understanding and distinguishing reflectance measurements of solid bitumen and vitrinite using hydrous pyrolysis: Implications to petroleum assessment

Hackley

Lewan

2018

Bulletin

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“…The EqVRo of the Qiongzhusi shale calculated from BRo is 2.85-3.53%, which is slightly higher than that from vitrinite-like particles (Table 3). The reflectance of vitrinite-like particles or macerals was used as maturity indicator in the Lower Palaeozoic source rocks (Buchardt & Lewan, 1990;Schmidt et al, 2015;Xiao et al, 2000).…”

Section: Maturity Evaluation Based On Optical Reflectancementioning

confidence: 99%

Maturity and thermal evolution differences between two sets of Lower Palaeozoic shales and its significance for shale gas formation in south‐western Sichuan Basin, China

et al. 2021

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The Lower Cambrian Qiongzhusi shale and the Upper Ordovician-Lower Silurian Wufeng-Longmaxi shale are major source rocks and important shale gas exploration targets in the Sichuan Basin. Cutting and core samples from two shale gas wells in south-western Sichuan Basin have been selected for organic matter (OM) reflectance measurement and Raman spectra analysis with the aim to determine maturity. The results were incorporated for basin modelling to construct the thermal evolution of this area. Graptolite fragments and pyrobitumens are the dominant form of OM in

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“…However, in sedimentary sequences that are lacking of vitrinite macerals, thermal maturation can be evaluated measuring reflectance on marine organoclasts (e.g. graptolites) (Xianming et al, 2000;Bertrand and Malo, 2012;Petersen et al, 2013;Schmidt et al, 2015). Therefore, in this work, the organic matter maturation was determined using both vitrinite and graptolite reflectance according to ASTM D7708-14 and ASTM D2797.…”

Section: Organic Matter Optical Analysesmentioning

confidence: 99%

“…Thereafter, vitrinite reflectance equivalent values (R o eq %) were obtained from graptolite and vitrinite-like fragments reflectance values using three different equations by Xianming et al (2000), Petersen et al (2013) and Schmidt et al (2015).…”

Section: Organic Matter Optical Analysesmentioning

confidence: 99%

“…The use of organoclasts reflectance for Paleozoic rocks revealed to be a successfully alternative (Bertrand and Malo, 2012;Poprawa et al, 2010;Petersen et al, 2013;Smolarek et al, 2014;Suárez-Ruiz et al, 2012). Neverthless, up to now, several equations that convert grapolites measurements into vitrinite-like reflectance values have been proposed (Xianming et al, 2000;Petersen et al, 2013;Schmidt et al, 2015) but they lead to a wide range of levels of HC generation (Table 4). For this reason, we coupled organic matter optical analyses with Rock Eval pyrolysis data, Raman spectroscopy performed on kerogen and X-ray diffraction of clay minerals, in order to correlate thermal maturity indicators against different conversion for Paleozoic organic matter reflectance.…”

Section: Ordovician To Devonian Successionsmentioning

confidence: 99%

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Assessment of thermal evolution of Paleozoic successions of the Holy Cross Mountains (Poland)

Schito

Corrado

Trolese

et al. 2017

Marine and Petroleum Geology

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Hydrous pyrolysis maturation of vitrinite-like and humic vitrinite macerals: Implications for thermal maturity analysis

Cited by 21 publications

References 20 publications

Understanding and distinguishing reflectance measurements of solid bitumen and vitrinite using hydrous pyrolysis: Implications to petroleum assessment

Understanding and distinguishing reflectance measurements of solid bitumen and vitrinite using hydrous pyrolysis: Implications to petroleum assessment

Maturity and thermal evolution differences between two sets of Lower Palaeozoic shales and its significance for shale gas formation in south‐western Sichuan Basin, China

Assessment of thermal evolution of Paleozoic successions of the Holy Cross Mountains (Poland)

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