25th International Meeting on Organic Geochemistry IMOG 2011

P-085
Flash pyrolysis-gas chromatography-mass spectrometry of
sulfur-rich native asphaltite, its asphaltenes, resins and oils
Vladimir Antipenko 1 , Vasilyi Melenevskiy 2
1 Institute of Petroleum Chemistry SB RAS, 4, Akademicheskiy Avenue, Tomsk, Russian Federation,
2 Trofimuk Institute of Oil and Gas Geology and Geophysics SB RAS, 3, Prosp. Acad. Koptuga, Novosibirsk,
Russian Federation (corresponding author:avr@ipc.tsc.ru)
Asphaltite recovered from Ivanovskoye oil field,
Orenburg region, and the products obtained
(asphaltenes, benzene and ethanol-benzene resins,
oil fractions) were characterized combining
successive flash-pyrolysis at the temperatures of 400
and 650 °С and ―on line‖ GC/MS analysis of the
yielded volatile products. It was determined that
compositions of the volatile products at 400 °С were
mainly determined by evaporation process, while
signs of thermodestruction of the products under
study were also observed.
The volatile products of high-temperature (650 °С)
flash pyrolysis of all the components of sulfur-rich
natural asphaltite contain the same set of compounds
(normal and isoprenoid alkanes, alkenes,
cyclohexanes, cheilanthanes and hopanes, hopenes
C27 and C30, pregnanes and steranes, mono-, bi-, tri-
and tetrasubstituted alkylbenzenes, (С1−С4)naphthalenes,
(С0−С4)-phenanthrenes, anthracene
and 2-methylanthracene, (С0−С4)-dibenzothiophenes
and (С1−С20)-benzothiophenes). It proves the
presence of major enumerated compounds in the
compositions of oil fractions and resin-asphaltene-
substances (RAS) of the natural asphaltite under
study as structural fragments.
By relative contents in the volatile products of a
high-temperature flash-pyrolysis the identified
compounds are ranged in the following series:
1) In case of oil fractions – (alkanes+alkenes),
alkylbenzenes, benzothiophenes, (hopanes +
hopenes), dibenzothiophenes, cyclohexanes,
naphthalenes, steranes and phenanthrenes;
2) In case of benzene resins –
(alkanes+alkenes), alkylbenzenes, benzothiophenes,
dibenzothiophenes, (cyclohexanes and
naphthalenes), (hopanes+hopenes), steranes and
phenanthrenes;
3) In case of ethanol-benzene resins –
(alkanes+alkenes), alkylbenzenes, benzothiophenes,
dibenzothiophenes, (cyclohexanes and
naphthalenes), (hopanes+hopenes), phenanthrenes
and steranes;
4) In case of asphalnetes – (alkanes+alkenes),
alkylbenzenes, benzothiophenes, dibenzothiophenes,
(cyclohexanes and naphthalenes), (hopanes+
hopenes), phenanthrenes and steranes.
For RAS these series are nearly identical
indicating genetic unity of resins and asphaltenes.
Total alkanes and alkenes are the most widespread
types of the compounds for all the initial samples in
the volatile products of the high-temperature flash
pyrolysis. Their total content varies from 80.4 to 86.5
%. Alkylbenzenes (8.7−12.6 %) are the second
compounds by their representation. Then one ranges
benzothiophenes (1.9−3.1 %) and dibenzothiophenes
(0.7−1.5 %) in accordance with the decrease in
relative contents
The calculations carried out taking into account the
yields of the volatile products of pyrolysis and coke
from the studied asphaltite components determined
using ―Rock Eval‖ device, demonstrate that paraffin
chains (24.0−56.7 %) and non-identified cock-forming
fragments (34.5−70.2 %) are the most widespread
structural fragments both in oil fractions and in RAS of
the asphaltite under study. Benzene (3.7−6.1 %)and
benzothiophene (0.9−1.3 %) cycles are presented in
the lesser degree.
Thus, combined low- and high-temperature ―on line‖
flash-pyrolysis is effective means aimed to obtain
information of the presence, forms of occurrence and
relative contents of different structural fragments in
RAS and oil fractions of the natural asphaltite.
The results obtained are meaningful to understand
the ways of catagenetic transformation of organic
matter in sedimentary rocks in order to predict
compositions of distillate fractions in the products of
thermal cracking of heavy oil residues and natural
bitumens as well as to extend our knowledge about
compositions of petroleum RAS and related natural
objects.
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