Study of petroleum generation by pyrolysis—I. Pyrolysis experiments by Rock-Eval and assumption of molecular structural change of kerogen using13C-NMR

Takeda, Nobuyori; Asakawa, Tadashi

doi:10.1016/0883-2927(88)90018-2

Cited by 27 publications

(9 citation statements)

References 7 publications

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“…As a result of this alteration in the intensity, it is conclusive that the maturation process would change the molecular structure of kerogen in terms of the molecular mass of the organic matter. This infers that the chemical structure of kerogen has been evolved while bond-breaking and forming have occurred [31]. Thus, we can at least conclude that MALDI result confirms the chemical structure changes by maturation.…”

Section: Molecular Characterization By Maldi-tof Mssupporting

confidence: 57%

Molecular Weight Distribution of Kerogen with MALDI-TOF-MS

Lee

Shokouhimehr²,

Ostadhassan³

et al. 2019

Preprint

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Kerogen is an amorphous organic matter (AOM) in fine grain sediments, which produces petroleum and other byproducts when subjected to adequate pressure and temperature (deep burial conditions). Chemical characteristics of kerogen by considering its biogenic origin, depositional environment, and thermal maturity has been studied extensively with different analytical methods, though its molecular structure is still not fully known. In this study, conventional geochemical methods were used to screen bulk rock aliquots from the Bakken Shale with varying thermal maturities. Organic matter was isolated from the mineral matrix and then a mass spectrometry method was utilized to quantify molecular weight distribution (MWD) of four different kerogens at various thermal maturity levels (immature to late mature). Furthermore, to complement mass spectrometry, Fourier transform infrared (FTIR) spectroscopy was employed as a qualitative chemical and structural investigation technique. The MWD of four samples was obtained by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, and the results are correlated with the absorption indices (CH3/CH2 ratio and aromaticity) calculated from the FTIR attenuated total reflectance (ATR) method. The results showed when the degree of maturity increases, the aliphatic length shortens, and the branching develops, as well as the aromatic structure becomes more abundant. Moreover, based on the MWD results, higher maturity kerogen samples would consist of larger size molecular structures, which are recognized as more developed aromatic, and aliphatic branching stretches. The combination of infrared spectroscopy (AFT-FTIR) and mass spectrometry (MALDI-TOF) provided MWD variations in kerogen samples as a function of maturity based on varying absorption indices and revealed the rate of change in molecular mass populations as a function of thermal maturity.

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Section: Molecular Characterization By Maldi-tof Mssupporting

confidence: 57%

Molecular Weight Distribution of Kerogen with MALDI-TOF-MS

Lee

Shokouhimehr²,

Ostadhassan³

et al. 2019

Preprint

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“…For example, NMR spectral features of kerogen are highly-correlated with the oil and gas potential of the source rock (Maciel et al, 1978(Maciel et al, , 1979Miknis et al, 1982;Qin et al, 1991;Witte et al, 1988). The genetic potential of oil shale is largely dependent on the abundance of aliphatic carbon (Takeda and Asakawa, 1988). The carbon functional groups in kerogen, as delineated by 13 C NMR, generally have prominent signals in the chemical shift regions corresponding to aliphatic (0 -90 ppm), olefinic/aromatic (90 -165 ppm), and carbonyl (165 -215 ppm) carbon (Resing et al, 1978;Vitorović et al, 1978).…”

Section: -Introductionmentioning

confidence: 99%

Organic structural properties of kerogen as predictors of source rock type and hydrocarbon potential

Longbottom

Hockaday

Boling

et al. 2016

Fuel

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This study improves upon previously identified correlations between the chemical structure of kerogen and potential hydrocarbon (oil and gas) yields assayed by Rock-Eval pyrolysis. We propose a quantitative structure-catagenesis relationship that predicts the hydrocarbon generation potential of source rocks and of lacustrine, marine, and terrestrial origin (types I, II, and humic coals). We used one-dimensional solid-state 13 C Nuclear Magnetic Resonance (13 C NMR) spectroscopy with 1 H spectral editing to determine the abundance of carbon functional groups, including non-protonated and mobile groups. An NMR-based van Krevelen analysis readily separated the kerogen types. Single regression matrices of NMR-based structure parameters against Rock-Eval hydrocarbon yield revealed distinct dynamics of the kerogen types upon pyrolysis. Multiple regression showed that alkyl, oxygen-substituted alkyl, and carbonyl groups were strong contributors to hydrocarbon production, while oxygen-substituted aromatic carbons were strongly counterproductive. Catagenetic relationships established for kerogen provide insight into kerogen structure evolution upon pyrolysis, and can more closely constrain the mechanisms of hydrocarbon generation for use in sedimentary basin modelling.

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“…1700 cm −1 (Robin, 1975;Tissot and Welte, 1984;Rullkötter and Michaelis, 1990;Lis et al, 2005). Concomitantly, these infrared analysis show that the decrease in the CO vibration continues up to 3% R 0 as reported for the Sarufutsu coals (Takeda and Asakawa, 1988). This might indicate that the release observed in Figure 4 will proceed slowly due to thermogenic degradation processes at maturity levels higher than covered by the current study.…”

Section: Lmw Organic Acids Linked To Nz Coals Of Different Maturitymentioning

confidence: 66%

A novel procedure to detect low molecular weight compounds released by alkaline ester cleavage from low maturity coals to assess its feedstock potential for deep microbial life

Glombitza¹,

Mangelsdorf²,

Horsfield³

2009

Organic Geochemistry

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. (2009): A novel procedure to detect low molecular weight compounds released by alkaline ester cleavage from low maturity coals to assess its feedstock potential for deep microbial life. -Organic Geochemistry, 40, 2, 175-183, DOI: 10.1016/j.orggeochem.2008 A novel procedure to detect low molecular weight compounds released by alkaline ester cleqavage from low mature coal to assess its feedstock potential for deep microbial life.Centre for Geosciences AbstractIn recent years the widespread occurrence of microorganisms was demonstrated in deep marine and terrestrial sediments. With this discovery inevitably the question of the potential carbon and energy sources for this deep subsurface microbial life arises. In the current study a new method for the investigation of low molecular weight (LMW) organic acids linked to the kerogen matrix is presented. These LMW organic acids form a potential feedstock for deep microbial populations. Twelve coal samples of different maturity (vitrinite reflectance (R 0 ) of 0.28 to 0.80%) from several coal mines on the North and South Island of New Zealand (NZ) were examined to assess the amount of bound LMW organic acids. Formate, acetate and oxalate were detected in significant amounts whereas the amounts of these compounds decrease with increasing maturity of the coal sample. This decrease of LMW

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Study of petroleum generation by pyrolysis—I. Pyrolysis experiments by Rock-Eval and assumption of molecular structural change of kerogen using13C-NMR

Cited by 27 publications

References 7 publications

Molecular Weight Distribution of Kerogen with MALDI-TOF-MS

Molecular Weight Distribution of Kerogen with MALDI-TOF-MS

Organic structural properties of kerogen as predictors of source rock type and hydrocarbon potential

A novel procedure to detect low molecular weight compounds released by alkaline ester cleavage from low maturity coals to assess its feedstock potential for deep microbial life

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