Potential Raman parameters to assess the thermal evolution of kerogens from different pyrolysis experiments

Du, Junyan; Geng, Ansong; Liao, Zewen; Cheng, Bin

doi:10.1016/j.jaap.2014.03.007

Cited by 26 publications

(8 citation statements)

References 20 publications

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“…Calcareous mudstone was selected from the upper Permian Lucaogou formation of Santanghu Basin, northwest China. The previously reported T max , production index (PI), and vitrinite reflectance ( R o ) values for the same calcareous mudstione used in this present study were ∼436 °C, ∼0.01, and 0.52%, indicating low maturity of the sample.…”

Section: Methodssupporting

confidence: 57%

Thermal Evolution of Adsorbed/Occluded Hydrocarbons inside Kerogens and Its Significance As Exemplified by One Low-Matured Kerogen from Santanghu Basin, Northwest China

Cheng

Tian

et al. 2016

Energy Fuels

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Organic compounds could be adsorbed and even occluded within the macromolecular structures of kerogen. Studies concerning thermal evolution of adsorbed/occluded hydrocarbons inside kerogens will be helpful in understanding its structural characteristics and evolution features and estimating the effectiveness of adsorbed and occluded fractions. In this work, adsorbed and occluded hydrocarbons have been released from a low-matured kerogen from the upper Permian Lucaogou formation of Santanghu Basin, northwest China, and from its pyrolysis residues by solvent extraction and oxidative treatment, respectively. The results showed that some n-alkanes, terpanes, and steranes were detected from both adsorbed and occluded fractions. Series of even-carbon-numbered n-alk-(1)-enes were also determined from the occluded components. The early stage of thermal evolution showed similarities in biomarker features for both adsorbed and occluded hydrocarbons; however, variations were noted in biomarker compositions with increasing thermal levels. The obvious changes of C 21−22 pregnane/C 27−29 sterane ratios from adsorbed to occluded fractions at high thermal evolution suggested that high concentrations of pregnane (containing homopregnane) in soluble components in highly or overly mature stage may be mainly derived from the corresponding components covalently bound within kerogen. Occluded components exhibited stronger thermal stability than adsorbed components. This study showed that evaluation of the thermal evolution characteristics of kerogens/source rocks based on biomarkers compositions from the adsorbed components at highly to overly matured stages was difficult, while we hope this kind of assessment of kerogens/source rocks can be achieved from occluded components.

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Section: Methodssupporting

confidence: 57%

Thermal Evolution of Adsorbed/Occluded Hydrocarbons inside Kerogens and Its Significance As Exemplified by One Low-Matured Kerogen from Santanghu Basin, Northwest China

Cheng

Tian

et al. 2016

Energy Fuels

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“…Spectra changed significantly in band shapes, positions, and relative intensity; the red shift and the sharpening of the main spectral features are marked with arrows. Following previous work and literature suggestions, ,,,, the following parameters were monitored (Figure b): G- and D-band positions and their full width at half-maximum fwhm (WG and WD, respectively); intensity, area, and fwhm ratios (IG/ID, Darea/Garea, WD/WG); separation between maxima: G-D and G R -D; the area ratios RA1 = [D + S L + S]/[G + G R + D 3 + D + S L + S] and RA2 = [D + S L + S]/[G + G R + D] …”

Section: Resultsmentioning

confidence: 97%

“…Spectra Energy & Fuels changed significantly in band shapes, positions, and relative intensity; the red shift and the sharpening of the main spectral features are marked with arrows. Following previous work 19 and literature suggestions, 13,17,20,26,27 the following parameters were monitored (Figure 3b):…”

Section: ■ Results and Discussionmentioning

confidence: 97%

“…In the literature, different fitting strategies are suggested, ,− , which are also dependent on the maturity level. The choice of the best parameters or parameter combinations to quantify the organic matter maturity is the subject of debate, ,, and so is the corresponding functional dependence on the maturity, which can be dependent on the metamorphic grade. In order to restrict the subjectivity in the manipulation of spectra, automated procedures have been presented that accomplish the spectral evaluation in a repeatable way. ,, Maturity-dependent variations of spectroscopic parameters are described ,− ,, in correlation with the maturity level (expressed as % R o , or as the paleotemperature) in sets of samples of low to high OM rank.…”

Section: Introductionmentioning

confidence: 99%

“…In order to restrict the subjectivity in the manipulation of spectra, automated procedures have been presented that accomplish the spectral evaluation in a repeatable way. ,, Maturity-dependent variations of spectroscopic parameters are described ,− ,, in correlation with the maturity level (expressed as % R o , or as the paleotemperature) in sets of samples of low to high OM rank. For samples in diagenesis to catagenesis zones, such as the ones examined here, useful parameters are generally: the D-G band separation; the full width at half maximum (fwhm) of the G band (WG) or of the D band (WD); the D/G area ratio; the WD/WG bandwidth ratio and the band area ratio RA2, ,,,, that were all tested in this experimentation.…”

Section: Introductionmentioning

confidence: 99%

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Organic Matter Maturity Profile of a Well Case Study by Combination of Raman Spectroscopy and Principal Component Analysis–Partial Least Squares Regression (PCA–PLS) Chemometric Methods

et al. 2018

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Raman spectroscopy is largely informative about organic matter (OM) chemical composition and structure and can therefore be applied to evaluate the thermal maturity of coals, carbonaceous materials and kerogens, i.e., their degree of evolution during burial heating. The evaluation of OM maturity is commonly performed by band-fitting followed by the measure of suitable spectral parameters (typically band separations and area ratios). However, this procedure can introduce some subjectivity both in the number and line-shape of the fitting bands and in the definition and selection of the most meaningful spectroscopic parameters. Here, a principal component analysis–partial least squares regression (PCA–PLS) chemometric approach for the treatment of spectra is presented, that is intrinsically unaffected by such arbitrariness. In fact, the total spectrum is analyzed in order to extract the spectroscopic ranges of maximum variance in a multivariate approach. In addition, being automated, the treatment is well-suited to huge sets, as those commonly collected to appropriately and reliably evaluate the chemical–physical and geological variables in an exploration well. As a case study the maturity profile (maximum paleotemperature) of OM from a well drilled in the Lower Congo basin (offshore Angola) is evaluated, both by spectral parameters and by PCA–PLS analysis, with results in good agreement on the basis of the prediction error. A set of coals is adopted as a reference to predict the reflectance in oil (%R o) profile from the Raman data. The comparison of the calculated %R o values with the experimental ones, presenting, in this case, some suppressed values, shows that the Raman analysis is not affected by underestimation of maturity as the vitrinite reflectance may be.

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A study of the relationships between coal structures and combustion characteristics: The insights from micro-Raman spectroscopy based on 32 kinds of Chinese coals

Tang

et al. 2018

Applied Energy

110

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Potential Raman parameters to assess the thermal evolution of kerogens from different pyrolysis experiments

Cited by 26 publications

References 20 publications

Thermal Evolution of Adsorbed/Occluded Hydrocarbons inside Kerogens and Its Significance As Exemplified by One Low-Matured Kerogen from Santanghu Basin, Northwest China

Thermal Evolution of Adsorbed/Occluded Hydrocarbons inside Kerogens and Its Significance As Exemplified by One Low-Matured Kerogen from Santanghu Basin, Northwest China

Organic Matter Maturity Profile of a Well Case Study by Combination of Raman Spectroscopy and Principal Component Analysis–Partial Least Squares Regression (PCA–PLS) Chemometric Methods

A study of the relationships between coal structures and combustion characteristics: The insights from micro-Raman spectroscopy based on 32 kinds of Chinese coals

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