New equation to decipher the relationship between carbon isotopic composition of methane and maturity of gas source rocks

2021 ◽  
Vol 64 (3) ◽  
pp. 470-493 ◽  
Author(s):  
Jianping Chen ◽  
Xulong Wang ◽  
Jianfa Chen ◽  
Yunyan Ni ◽  
Baoli Xiang ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Carbon Isotopic Composition ◽  
Source Rocks ◽  
Carbon Isotopic ◽  
Gas Source ◽  
New Equation ◽  
The Relationship

scholarly journals Geological and geochemical conditions for the formation of the oil composition in the deposits of the Permian and Jurassic oil and gas complexes in the Fukang depression (Junggar basin)

Georesursy ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 110-119
Author(s):  
Houqiang Yang ◽  
Elena V. Soboleva
Keyword(s):  
Isotopic Composition ◽  
Middle Jurassic ◽  
Oil And Gas ◽  
Carbon Isotopic Composition ◽  
Source Rocks ◽  
Middle Permian ◽  
Geochemical Conditions ◽  
Carbon Isotopic ◽  
Gas Source ◽  
Β Carotene

Within the eastern part of the Fukang depression, the main productive series are confined to the Permian and Jurassic oil and gas complexes (OGC), in which the Middle Permian and Lower-Middle Jurassic oil and gas source rocks (OGSRs) are distinguished. The article discusses in detail the oil and gas source characteristics of the Middle Permian and Lower-Middle Jurassic rocks, the molecular composition of oils and bitumoids from the OGSRs, and also interprets the characteristics of the biomarkers in them from the standpoint of the sedimentary-migration theory of oil generation. An attempt is made to explain the reasons for the difference in the properties and composition of oils from different OGCs. It is shown that the composition of hydrocarbon fluids of deposits is determined not only by the geological and geochemical conditions of sedimentation of oil and gas source deposits, but also associated with migration processes and subsequent secondary changes in the accumulation. In terms of composition, three groups of oils were identified: Permian and Jurassic heavy oils with a light carbon isotopic composition and the presence of β-carotene and gammacerane, they underwent different degrees of biodegradation, which depended on the geological conditions of the deposits; Permian medium oils in density (0.84 and 0.87 g/cm3), the composition of biomarkers of which is very close to that of the first group, and Jurassic light oils with a high content of solid paraffins and a heavier carbon isotopic composition, almost do not contain β-carotene and gammacerane concentrations are low.

scholarly journals Isotopic composition of blood plasma carbon in patients with endocrine diseases

1993 ◽  
Vol 39 (1) ◽  
pp. 36-40
Author(s):  
A. A. Ivlev ◽  
N. P. Goncharov
Keyword(s):  
Isotopic Composition ◽  
Blood Plasma ◽  
Carbon Isotopic Composition ◽  
Mean Value ◽  
Cellular Division ◽  
Disease Heterogeneity ◽  
Clear Cut ◽  
Carbon Isotopic ◽  
Adults And Children ◽  
The Relationship

Forty-eight patients suffering from diabetes mellitus, obesity, hyper- and hypothyrosis, Icenko-Cushings disease were examined to elucidate the relationship between blood plasma carbon isotopic composition and the type of the endocrine disease. This value varied within the range of 19.7 to 24.7 , the mean value being 5 . Blood plasma carbon in the diabetics is enriched for 12C light isotope (delta-13C from 23.0 to 24.5 ) as against a similar characteristic in obese patients (delta-13C from 20.5 to 21.99 ). Patients with hypo- and hyperthyrosis and the Icenko- Cushings disease have a wider range of delta-13C values that seems to be explained by the Icenko-Cushings disease heterogeneity and the presence of biorhythms. Clear-cut isotopic differences in the blood sera of adults and children were revealed whatever the disease type, these differences indicating the changes in cellular metabolism energy in the ontogenesis. These data can be satisfactorily explained within the frames of the model of cellular division of carbon isotopes, suggested previously.

Developing Micro-Raman Mass Spectrometry for Measuring Carbon Isotopic Composition of Carbon Dioxide

2007 ◽  
Vol 61 (7) ◽  
pp. 701-705 ◽  
Author(s):  
Masashi Arakawa ◽  
Junji Yamamoto ◽  
Hiroyuki Kagi
Keyword(s):  
Isotopic Composition ◽  
Intensity Ratio ◽  
High Spatial Resolution ◽  
Carbon Isotopic Composition ◽  
Peak Intensity Ratio ◽  
Factors Affecting ◽  
Isotopic Compositions ◽  
Carbon Isotopic ◽  
Peak Intensity ◽  
The Relationship

We investigated the applicability of micro-Raman spectroscopy for determining carbon isotopic compositions (13C/12C) of minute CO2 fluid inclusions in minerals. This method is nondestructive and has sufficiently high spatial resolution (1 μm) to measure each fluid inclusion independently. Raman spectra of CO2 fluid have 12CO2-origin peaks at about 1285 cm−1 and 1389 cm−1 (v12− and v12+) and a 13CO2-origin peak at about 1370 cm−1 (v13+). The relationship between carbon isotopic compositions and peak intensity ratios of v12+ and v13+ was calibrated. Considering several factors affecting the peak intensity ratio, the error in obtained carbon isotopic composition was 2% (20‰). The reproducibility of the intensity ratio under the same experimental environment was 0.5% (5‰). Within these error values, we can distinguish biogenic CO2 from abiogenic CO2.

scholarly journals Hydrocarbon biomarkers and isotopic composition of carbon from bitumoids and oils of Mesozoic sediments in the western part of the Yenisei-Khatanga oil and gas region

Georesursy ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 47-63
Author(s):  
Alexander P. Afanasenkov ◽  
Tatyana P. Zheglova ◽  
Alexander L. Petrov
Keyword(s):  
Isotopic Composition ◽  
Oil And Gas ◽  
Carbon Isotopic Composition ◽  
Source Rocks ◽  
Type I ◽  
Composition Distribution ◽  
Carbon Isotopic ◽  
Hydrocarbon Biomarkers ◽  
Humus Type ◽  
Hydrocarbon Deposits

Based on analyzes of carbon isotopic composition, distribution and composition of hydrocarbon biomarkers of oils and bitumoids from source rocks of the Mesozoic sediments in the western part of the Yenisei-Khatanga oil and gas region and the northeast of the West-Siberian plate, two groups of oils and bitumoids are identified, genetically associated with organic matter, mainly sapropel type (I group) and mainly humus type (II group). The genetic correlation of oils and bitumoids has been made. Possible foci of generation, which participated in the formation of hydrocarbon deposits, have been determined.

UNDERSTANDING SOURCE, DISTRIBUTION AND PRESERVATION OF AUSTRALIAN NATURAL GAS: A GEOCHEMICAL PERSPECTIVE

2001 ◽  
Vol 41 (1) ◽  
pp. 523 ◽  
Author(s):  
C.J. Boreham ◽  
J.M. Hope ◽  
B. Hartung-Kagi
Keyword(s):  
Organic Matter ◽  
Natural Gas ◽  
Isotopic Composition ◽  
Carbon Isotopic Composition ◽  
Source Rocks ◽  
Source Distribution ◽  
Hydrocarbon Gases ◽  
Carbon Isotopic ◽  
Wet Gas ◽  
Gaseous Hydrocarbons

Natural gases from all of Australia’s major gas provinces in the Adavale, Amadeus, Bass, Bonaparte, Bowen/ Surat, Browse, Canning, Carnarvon, Cooper/Eromanga, Duntroon, Gippsland, Otway and Perth basins have been examined using molecular and carbon isotopic compositions in order to define their source, maturity and secondary alteration processes.The molecular compositions of the gaseous hydrocarbons range from highly wet to extremely dry. On average, reservoired gases predominantly derived from land plants are slightly wetter than those derived from marine sources. The non-hydrocarbon gases CO2 and N2 were sourced from both inorganic and organic materials. A mantle and/or igneous origin is likely in the majority of gases with CO2 contents >5%. For gases with lower CO2 contents, an additional organic input, associated with hydrocarbon generation, is recognised where δ13C CO2 is A strong inter-dependency between source and maturity has been recognised from the carbon isotopic composition of individual gaseous hydrocarbons. This relationship has highlighted some shortcomings of common graphical tools for interpretation of carbon isotopic data. The combination of the carbon isotopic composition of gaseous hydrocarbons and the low molecular weight nalkanes in the accompanying oil allows our knowledge of oil-source correlations and oil families to be used to correlate gases with their sources. This approach has identified source rocks for gas ranging in age from the Ordovician in the Amadeus Basin to Late Cretaceous- Early Tertiary sources in the Bass and Gippsland basins. The carbon isotopic composition of organic matter, approximated using the δ13C of iso-butane, shows a progressive enrichment in 13C with decreasing source age, together with marine source rocks for gas being isotopically lighter than those from land plant sources. The Permian was a time when organic matter was enriched in 13C and isotopically uniform on a regional scale.Secondary, in-reservoir alteration has played a major role in the modification of Australian gas accumulations. Thus, biodegradation, prominent in the Bowen/Surat, Browse, Carnarvon and Gippsland basins, is found in both hydrocarbon and non-hydrocarbon gases. This is recognised by an increase in gas dryness, elevated isoalkane to n-alkane ratio, differential increase in δ13C of the individual wet gas components, a decrease in δ13C of methane and a reduction in CO2 content concomitant with enrichment in 13C. Evidence of water-washing has been identified in accumulations in the Bonaparte and Cooper/Eromanga basins, resulting in an increase in the wet gas content. Seal integrity is also a major risk for the preservation of natural gas accumulations, although its effect on gas composition is only evident in extreme cases, such as the Amadeus Basin, where preferential leakage of methane in the Palm Valley field has resulted in the residual methane becoming enriched in 13C.The greater mobility of gas within subsurface rocks can have a detrimental effect on oil composition whereby gas-stripping of light hydrocarbons is common amongst Australian oil accumulations. Alternatively, the availability of gas, derived from a source rock common to or different from oil, was likely to have been a prime factor controlling the regional distribution of oil, whereby mixing of both results in increased oil mobility and can lead to a greater access to the number and types of traps in the subsurface.

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