T max of asphaltenes: a parameter for oil maturity assessment

Nali, M.; G, Caccialanza; Ghiselli, C.; Chiaramonte, M. A.

doi:10.1016/s0146-6380(00)00068-1

Cited by 32 publications

(10 citation statements)

References 13 publications

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“…Because mature organic matter is more condensed, it is more difficult to pyrolyze as a result of higher activation energies, thus, T max is inherently linked to the kinetics of organic matter cracking. In cases of Types II and III, organic matter reaches catagenesis at a T max of 435°C (Nali et al 2000). The present results show that T max in ranges from 403 to 418°C for core 03GHP-01, from 314 to 415°C for core 03GHP-02, from 314 to 426°C for core 03GHP-03 and from 329 to 419°C for core 03GHP-04 ( Fig.…”

Section: T Maxsupporting

confidence: 56%

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Geochemical characterization of the organic matter, pore water constituents and shallow methane gas in the eastern part of the Ulleung Basin, East Sea (Japan Sea)

Kim

Park²,

Tsunogai

et al. 2007

Island Arc

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Geochemical analyses of sediments, pore water and headspace gas of the piston cores taken from the eastern part of Ulleung Basin of the East Sea (Japan Sea) were carried out to assess the origin of the sedimentary organic matter and interstitial fluid. Several tephra layers within the core are identified as the Ulleung‐Oki (10.1 ka), the Aira‐Tanzawa (23 ka) and the Ulleung‐Yamato (30.9 ka) tephras. With the exception of these volcanic layers, the cores consist predominantly of muddy sediments that contain >0.5% total organic carbon. Atomic C/N ratios and δ13Corg values suggest that the organic matter originated from marine algae rather than from land vascular plants, whereas Rock‐Eval pyrolysis suggests that the organic matter is thermally immature and comes from a land vascular plant (Type III). These conflicting results seem to be caused by the heavy oxidization of the marine organic matter. Sulphate concentration profiles of pore waters show strongly linear depletion (r2 > 0.97) with sediment depth. The estimated sulphate–methane interface (SMI) depth using the sulphate concentration gradient was nearly 3.5 m below seafloor (mbsf) in the southern part of the study area, and deeper than 6 mbsf in the northern part of the area. The difference in SMI depths is likely associated with the amount of the methane flux. The methane concentration below the SMI in the two southern cores increases rapidly, implying the occurrence of methanogenesis and anaerobic methane oxidation (AMO). In contrast, the two northern cores have a low methane concentration below the SMI. values measured from all cores were in the range of −83.5 to −69.5‰, which suggests that the methane derives from a methanogenic microbe. values become decreased toward SMI, but increased below SMI; therefore, has eventually the minimum value near the SMI. The values are also decreased when the methane concentration is increased. These phenomena support the typical occurrence of AMO in the study area.

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Section: T Maxsupporting

confidence: 56%

Section: Origin and Maturation Of Organic Mattermentioning

confidence: 99%

Geochemical characterization of the organic matter, pore water constituents and shallow methane gas in the eastern part of the Ulleung Basin, East Sea (Japan Sea)

Kim

Park²,

Tsunogai

et al. 2007

Island Arc

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“…Oil asphaltenes were selected to be investigated for the following reasons: first, oil asphaltenes were produced in the early maturation stage of organic matter and have a structure more similar to that of kerogen than other components in the oils [14] ; secondly, compared with other components in the oils, oil asphaltenes are hardly affected by biodegradation and water washing [15] ; thirdly, the changes in physical phase during oil mixing, such as precipitation of asphaltenes, have little effect on the molecular structure of oil asphaltenes [16] ; and finally, molecular structures of oil asphaltenes show little variations during oil transfer [17] . However, the above factors may have significant effects on the low molecular biomarkers and may be the main cause that can account for the debate on the oil/source correlations in the Tarim Basin [1] .…”

Section: Samplesmentioning

confidence: 99%

Carbon isotopic compositions of 1,2,3,4-tetramethylbenzene in marine oil asphaltenes from the Tarim Basin: Evidence for the source formed in a strongly reducing environment

Jia

Peng

Xiao

2008

Sci. China Ser. D-Earth Sci.

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Although 1-alkyl-2,3,6-trimethylbenzenes and a high relative amount of 1,2,3,4-tetramethylbenzene have been detected in marine oils and oil asphaltenes from Tabei uplift in the Tarim Basin, their biological sources are not determined. This paper deals with the molecular characteristics of typical marine oil asphaltenes from Tabei and Tazhong uplift in the Tarim Basin and the stable carbon isotopic signatures of individual compounds in the pyrolysates of these asphaltenes using flash pyrolysis-gas chromatograph-mass spectrometer (PY-GC-MS) and gas chromatograph-stable isotope ratio mass spectrometer (GC-C-IRMS), respectively. Relatively abundant 1,2,3,4-tetramethylbenzene is detected in the pyrolysates of these marine oil asphaltenes from the Tarim Basin. δ 13 C values of 1,2,3,4-tetramethylbenzene in the pyrolysates of oil asphaltenes vary from −19.6‰ to −24.0‰, while those of n-alkanes in the pyrolysates show a range from −33.2‰ to −35.1‰. The 1,2,3,4-tetramethylbenzene in the pyrolysates of oil asphaltenes proves to be significantly enriched in 13 C relative to n-alkanes in the pyrolysates and oil asphaltenes by 10.8‰-15.2‰ and 8.4‰-13.4‰, respectively. This result indicates a contribution from photosynthetic green sulfur bacteria Chlorobiaceae to relatively abundant 1,2,3,4-tetramethylbenzene in marine oil asphaltenes from the Tarim Basin. Hence, it can be speculated that the source of most marine oil asphaltenes from the Tarim Basin was formed in a strongly reducing water body enriched in H 2 S under euxinic conditions.

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“…The Rock-Eval T max of oil shale and mudstone from both members is 429-452 °C, indicating that these rocks are immature to marginally mature (Fig. 4, Table) [20], which is equivalent to a vitrinite reflectance (Ro) of about 0.5% Ro [16].…”

Section: Characteristics Of Organic Matter and Accumulation Conditionmentioning

confidence: 99%

Multiple Controlling Factors of the Enrichment of Organic Matter in the Upper Cretaceous Oil Shale Sequences of the Songliao Basin, Ne China: Implications From Geochemical Analyses

Song¹,

Liu²,

Meng³

et al. 2016

Oil Shale

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Two oil shale sequences in the Upper Cretaceous Qingshankou and Nenjiang Formations of the Songliao Basin, NE China, representing organic matter (OM)-rich hydrocarbon source rocks, are investigated. According to bulk and inorganic geochemical data, there are significant differences in OM enrichment conditions between the first member of the Qingshankou Formation (K 2 qn 1) and the second member of the Nenjiang Formation (K 2 n 2). The oil shale in K 2 qn 1 was deposited in a warm-humid paleoclimate, with strong water salinity stratification and dysoxic conditions, combined with high bioproductivity and low detrital matter input. In contrast, the oil shale in K 2 n 2 was accumulated in a warm semi-humid paleoclimate, with weak water salinity stratification and partially oxic conditions, when the bioproductivity and detrital matter input were medium. In addition, the origin of OM influenced its enrichment. In summary, high bioproductivity and strong water salinity stratification were the major controlling factors for OM enrichment in K 2 qn 1 , while the origin of OM and dysoxic conditions were the major governing factors for OM enrichment in K 2 n 2. Thus, the OM enrichment models of these two members are established.

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T max of asphaltenes: a parameter for oil maturity assessment

Cited by 32 publications

References 13 publications

Geochemical characterization of the organic matter, pore water constituents and shallow methane gas in the eastern part of the Ulleung Basin, East Sea (Japan Sea)

Geochemical characterization of the organic matter, pore water constituents and shallow methane gas in the eastern part of the Ulleung Basin, East Sea (Japan Sea)

Carbon isotopic compositions of 1,2,3,4-tetramethylbenzene in marine oil asphaltenes from the Tarim Basin: Evidence for the source formed in a strongly reducing environment

Multiple Controlling Factors of the Enrichment of Organic Matter in the Upper Cretaceous Oil Shale Sequences of the Songliao Basin, Ne China: Implications From Geochemical Analyses

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