Kerogen: chemical structure and formation conditions

Бушнев, Д. А.; Burdelnaya, N. S.

doi:10.1016/j.rgg.2008.12.004

Cited by 17 publications

(7 citation statements)

References 19 publications

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“…In particular, in the kerogens of Middle Volga domanik rocks, carbonoxygen bonds were identified as dominant [40]. The kerogen contains monosaccharide units of n-alkyl chains bearing alcohol, keto, and aldehyde substituent groups [41], as well as long-chain C 19 -C 32 carboxylic acids [42]. Therefore, in the kerogen structure degradation processes, both free oxygen and oxygen-containing fragments can be released, which can be present in asphaltene and carbenes-carboid fractions and, in the form of oxygen-containing compounds, in hydrocarbon fractions.…”

Section: Characterization Of Asphaltenes and Carbenes-carboidsmentioning

confidence: 99%

Transformation of Organic Matter of Domanik Rock from the Romashkino Oilfield in Sub- and Supercritical Water

et al. 2020

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The transformation of the organic matter (OM) of low-permeable carbon-rich domanik rock of the Romashkino oilfield in sub-and supercritical water (SCW) at temperatures of 320, 374, and 420°C and pressures of 17, 24.6, and 24.4 MPa in a neutral medium has been studied. The original rock with a TOC content of 7% has a high oil generation potential and a low productivity index. The productivity index increases with an increase in the severity of the thermal treatment of the rock, which is due to intense kerogen degradation resulting in the formation of free hydrocarbons that are easy to recover from the rock. In rock extracts, in comparison with the original rock, the amount of saturated and aromatic hydrocarbons increases by more than two times and that of resin-asphaltene substances decreases. Distinctive features of the yields and compositions of rock extracts depending on the temperature of the experiments have been revealed. The highest yield of the extract was observed in the experiment with subcritical water at 320°C and associated with the degradation of resins and more complete extraction of asphaltenes and high-molecular-weight n-alkanes from the rock. Treatment in SCW at 374 and 420°C leads to intensive degradation of the kerogen structure involving the detachment of aliphatic chains from large fragments of kerogen and asphaltene macromolecules to form lower n-alkanes and carbon-rich substances, such as carbenes and carboids. The structure of asphaltenes becomes more condensed and oxidized in the SCW medium at 420°С, leading to a decrease in their paramagnetic properties. Using the EPR technique, the features of hyperfine splitting of the vanadyl complex line on 14 N nitrogen nuclei have been revealed in the spectrum of asphaltenes of the SCW experiment at 420°С, indicating specific changes in their structure.

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Section: Characterization Of Asphaltenes and Carbenes-carboidsmentioning

confidence: 99%

Transformation of Organic Matter of Domanik Rock from the Romashkino Oilfield in Sub- and Supercritical Water

et al. 2020

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“…The above-mentioned can be explained in terms of hydrogen disproportionation and a rise in the aromaticity degree of the test products forming as a result of kerogen destruction in the hydrothermal process. Similar changes also occur in the processes of natural catagenesis of the organic matter from Domanic source rocks . Sufficiently high nitrogen content (1.44 and 1.66) in the Domanic bitumen extracts can give evidence of its immaturity.…”

Section: Resultsmentioning

confidence: 76%

“…The kerogen from the Domanic rock sample is extremely unstable during hydrothermal processes, which to a great extent leads to a decrease in its content (as a result of its destruction) from 25.43 to 6.62%. According to some modern concepts, kerogen is a natural geopolymer of the irregular structure and is considered to be one of the possible sources of oil hydrocarbon generation. , The content of light hydrocarbons in the rock also decreases significantly (from 10.17 to 6.30%) after the experiment within the temperature interval of 200–400 °C, presumably due to the easiness of their washing-out from the rocks.…”

Section: Resultsmentioning

confidence: 99%

Conversion of the Organic Matter of Domanic Shale and Permian Bituminous Rocks in Hydrothermal Catalytic Processes

et al. 2017

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Comparative studies of hydrothermal transformation of organic matter samples of bituminous rocks from Domanic and Permian deposits of the Tatarstan Republic (Russian Federation) have been carried out. The experiments have been taken at a temperature of 300 °C in a vapor-gas carbon dioxide environment, with a content of 30% water in the reactionary system and an initial pressure of carbon dioxide of 2 MPa. It is shown that the distinguishing features of the organic matter of the analyzed species according to thermal analysis data are most prominent in the loss of its mass at various temperature intervals. Also, changes take place in group and structural composition and hydrocarbon composition, which have an impact on the composition of the initial products of experiments. Hydrothermal effects on the Domanic rock sample result in the destruction of structural polymer fragments of kerogen. It results in an increase in the contents of asphaltenes and their modified structures in the form of carben-carboids, insoluble in solvents characteristic of asphaltenes, thus reducing the relative content of saturated hydrocarbons in the products of the experiment. Under similar hydrothermal conditions, changes in the physical composition of the Permian rock are less significant. For the investigation of activation processes of the transformation of organic matter of the Permian rock, an experiment was conducted using catalysts. As catalysts, a composition of oil-soluble iron(II), cobalt(II), and copper(II) carboxylates with an additive of propanol was used. The use of the catalyst has increased the output of light fractions and reduced the content of resins and asphaltenes as part of Permian rock.

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“…The oil-bearing capacity of Romashkino oil field is concentrated in 22 horizons, where the most important reservoirs are in Pashian and Timan horizons. These reservoirs belong to terrigenous deposits of Frasnian strata of Upper The last investigations give reasons to imply that the oilgenerating potential of Domanic deposits from Romashkino oil field is not finished yet as a burial depth, and hence, the thermal history is not enough to cover the intensive generation of hydrocarbons that is crucial for "oil window" [4,11,21,22]. Consequently, hydrothermal and pyrolytic influences on the tight rocks will provide artificial thermal maturity of kerogen with the formation of oil in liquid phase, thus increasing the oil recovery factor of reservoirs.…”

Section: Methodsmentioning

confidence: 99%

“…The increased interest in high-carbon rocks, which are rich in organic matter (OM), is associated with their reserves and perspectives of shale oil production [1][2][3][4][5]. An analogue of the shale formations in Russia is the house deposits of the Volga-Ural oil and gas basin which stratigraphically belong to the Fransnian stage of Upper Devonian age.…”

Section: Introductionmentioning

confidence: 99%

Influence of Hydrothermal and Pyrolysis Processes on the Transformation of Organic Matter of Dense Low-Permeability Rocks from Domanic Formations of the Romashkino Oil Field

et al. 2018

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The model experiments regarding the conversion of organic matters from carbonate rock samples of Dankov-Lebedyan deposits of Zelenogorskaya area and siliceous-carbonate rocks of Semiluki-Mendym deposits of Berezovskaya area of Domanic formations of Romashkino oil field were carried out. Two types of experiments were carried out: (1) the hydrothermal treatment of rocks at a temperature of 350°C in the presence of carbonic acid and a water content of 30%; (2) pyrolysis at temperatures of 350 and 600°C in the presence of hydrogen. The yield and quality of extracted hydrocarbons from the rocks depending on the mineral composition of rocks, content and composition of organic matter, and thermal stability of kerogen under hydrothermal influences were evaluated. Application of electron paramagnetic resonance in pyrolysis processes revealed the difference in mineral content of rocks (Mn2+, SO3−, and SO2− ions) and free radicals R∗, as well as in vanadyl ion (VO2+) concentration. It is established that an increasing temperature of pyrolysis promotes the formation of new free organic radicals in rock samples: in Domanic rocks of Semiluki-Mendym deposits at 350°С and in carbonate rocks of Dankov-Lebedyan horizon at 600°С. This indicates different ability of oil-generating potential of rocks with hydrothermal and pyrolysis technologies.

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Kerogen: chemical structure and formation conditions

Cited by 17 publications

References 19 publications

Transformation of Organic Matter of Domanik Rock from the Romashkino Oilfield in Sub- and Supercritical Water

Transformation of Organic Matter of Domanik Rock from the Romashkino Oilfield in Sub- and Supercritical Water

Conversion of the Organic Matter of Domanic Shale and Permian Bituminous Rocks in Hydrothermal Catalytic Processes

Influence of Hydrothermal and Pyrolysis Processes on the Transformation of Organic Matter of Dense Low-Permeability Rocks from Domanic Formations of the Romashkino Oil Field

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