Twelve hydrothermal autoclave experiments were conducted with Domanik oil shale from the Ukhta region (Chut River) at temperatures of 250–375°C and run duration of 24 h (6 experiments), 72 h (5 experiments), and 48 h (1 experiment). The composition of hydrocarbon gases C1–C5 was studied for each experiment and quantitative data on their yields were obtained. Based on these data, the distributions of generation potential of individual gaseous hydrocarbons by activation energy were established under hydrothermal experimental conditions. The character of the kinetic spectra of individual alkanes C2–C5 is virtually identical; their main narrow maximum corresponds to Ea 55 kcal/mol with an Arrhenius factor of 1 × 1014 s–1. The distribution of the methane generation potential by activation energies is distinguished by the fact that a significant part of its generation potential falls within the region of activation energies of 60–70 kcal/mol and by the uncertainty of the distribution character in this region.

A series of kerogen samples were isolated from Domanik oil shale before and after hydrothermal treatment in an autoclave (at 250–375°C, for 24 h). Than composition of the C1–C5 hydrocarbon gases generated in stepwise (300–800°C) pyrolysis of these kerogens was characterized by gas chromatography. According to the calculated EASY

Ashless extracts, hypercoals, were obtained from Tuvan coals of the Ulug-Khem basin by dissolving them in N-methylpyrrolidone. The yield of the extracts was 27.3–79.4

The article presents the results of determining the kinetic characteristics of the formation of individual hydrocarbon gases at different stages of artificially increased thermal maturity of the Domanik shale from an Chut River outcrop (Ukhta District). Based on the data of stepwise pyrolysis of residual kerogen isolated from the shale after hydrothermal treatment, the distributions of the formation potential of individual hydrocarbons of the composition C1—C5 by the activation energy scale (kinetic spectra) were determined. The kinetic spectra of n butane and n pentane do not change with increasing temperature of the hydrothermal experiment and increasing maturity of the organic matter. The maximum of the potential distribution on the activation energy scale of methane and ethane shifts to the region of higher values with increasing thermal maturity. The results can be used to clarify the conditions for the implementation of the gas formation potential in the domanik deposits of the Timan-Pechora basin.

We carried out the analytical oxidation of kerogen samples from oil shales of Ordovician kukersite from the Baltic region, Domanik shales from Timan-Pechora and Upper Jurassic oil shales of the Kashpir deposit by potassium permanganate in an alkaline medium. We performed a single-stage oxidation with 3.5 % solution of potassium permanganate, followed by analysis of trimethylsilyl derivatives of carboxylic acids using chromatography-mass spectrometry, and multi-stage oxidation by 0.5 % solution of potassium permanganate and analysis of oxidation products using IR spectroscopy. Some n-alkyl structures are peripherally associated with the kerogen matrix in the kerogen of Domanik and Jurassic shales, while in the structure of kukersite kerogen, n-alkyl structures are mainly connecting links for larger fragments. Milder, in case of a multi-stage process, oxidation results in formation of large fragments of kerogen, generally repeating its carbon structure, but more oxidized.

A sample of Domanik shale from a stratotype section along the river Chut (Ukhta District, Komi Republic, Russia) was affected to temperatures of 250—375 °C in an autoclave in the presence of water. The composition and yield of the resulting hydrocarbon gases was studied by gas chromatography. The yield of all C1—C5 hydrocarbons grew exponentially with increasing temperature in the autoclave. The total yield of gaseous hydrocarbons C1—C5 at 375 °C was 71 mg/g Corg and reached 18 mg/g Corg for methane. The increasing temperature in the autoclave resulted in decreasing ratio of methane/C2+ gases, which reflected a changing mechanism of methane formation at the corresponding stage of the thermal evolution of the Domanik organic matter.

This is a retrospective review of existing knowledge and major research areas related to the structure of asphaltenes and their applicability in petroleum and organic geochemistry. The paper emphasizes the great potential of the current analytic base for further research into the structural elements, functional groups, and intermolecular interaction mechanisms of asphaltenes from crude oils, natural bitumens, and sedimentary rock extracts. The principal methods for investigating the composition and structure of asphaltenes are described from the perspective of solving the pressing challenges of organic geochemistry. Geochemical interpretation of the chemical and supramolecular structures of asphaltenes provides valuable information in addition to the data on the structural elements of asphaltenes and their binding modes. Accumulation of relevant data on the molecular and supramolecular structures of asphaltenes is of considerable importance for a deeper understanding of their behaviors and for unraveling the correlations between crude oils and precursor sedimentary organic matter.

—It has been established that the average values of some hydrocarbons biomarker coefficients of bitumens from the Domanik deposits and oils from the Domanik–Tournaisian complex coincide. These are the proportions of C 27 –C 29 steranes, tri-/pentacyclanes ratio, and coefficients 2 × С 17 /С 16 + С 18 and 2 × С 27 /С 26 + С 28 calculated from n -alkane composition. Such indicators as the Pr/Ph, (Pr + Ph)/( n ‑C 17 + n ‑C 18 ), dia-/reg-steranes, and the sterane/hopane ratios in oils are slightly lower than in the bitumen. The average values of δ 13 C in asphaltene, resin, aromatic hydrocarbons, and aliphatic hydrocarbons fractions from oils of the Domanik genotype and in the studied bitumens are similar. The carbon isotope composition of asphaltenes in oils is depleted in 13 С compared to those of resins and aromatic hydrocarbons, and vice versa in bitumens. A heterogeneous composition of the bacterial flora in the sediments of the Domanik Sea is suggested. In some places, species with high concentrations of diplopterol or hexafunctional bacteriohopanes likely dominated over bacteriohopantetrol.

The composition of hydrocarbon gases formed by pyrolysis of residual Domanik shale kerogen at 800°C, preceded by hydrothermal treatment at 250–375°С, was studied by pyrolytic gas chromatography. Starting from the autoclave temperature of 320–325°C, the hydrothermal treatment of the shale affects the kerogen structures responsible for the formation of C 2+ gases in pyrolysis at 800°C. An increase in the temperature of the shale hydrothermal treatment leads to a monotonic increase in the С 1 /С 2+ ratio in the products of the residual kerogen pyrolysis at 800°C. The methane yield at 800°C does not correlate with the content of alkyl structures, determined in kerogen by IR spectroscopy, and the yield of С 2+ gases linearly correlates with the content of alkyl structures.

The peat from the Cherny Yar section at the Vychegda river was studied by a complex of palynological and geochemical methods. We determined that among the aliphatic hydrocarbons of bitumen, the maximum concentrations were characteristic for odd n-alkanes with a predominance of C27-C31 homologues, as well as 18-norabietane. Aromatic hydrocarbons are mainly represented by structures formed during the fossilization of diterpenoids and triterpenoids of higher vegetation. Among the aromatic diterpenoids, there are 18-norabieta-8,11,13-triene, 18-norsimonellite and retene, which are markers of conifers, as well as 18-norabietane of the aliphatic fraction. Among the aromatic triterpenoids, numerous transformation products of compounds with the carbon skeleton of lupan, oleanan, and ursane, characteristic of angiosperms, have been identified. For example, dinorolean(ursa)-1,3,5(10),13(18)-tetraene, dinorolean(ursa)-1,3,5(10)-triene, pentanoroleana-1,3,5(10), 6,8,11,13,17(18)-octaene and others. The data on the composition of hydrocarbons confirm the palynological data about the presence of coniferous and hardwood pollen in the composition of peat. The change in the composition of hydrocarbons along the section confirms the change in the species composition of vegetation in the study area, diagnosed by microfossils. The comparison of the composition of peat biomarker hydrocarbons with palynological data revealed their consistency with each other and possibility of conjugated use of these methods in paleogeographic reconstructions.

The composition and distribution of alkylbenzenes, alkyltoluenes, and 2-methyl-2-(4,8,12-trimethyltridecyl)chromans (MTTC) in the aromatic hydrocarbon fraction isolated from the Lower Permian silty-clayey and salt rocks of the Upper Pechora potassium–magnesium salt basin (Yakshinskoe deposit) are presented. The studies have shown the wide distribution of alkylbenzenes and alkyltoluenes under hypersaline environment (stages of the halite and sylvite precipitation) at low organic matter maturity. The revealed differences in n-alkylbenzenes and n-alkyltoluene distributions are associated with the predominance of various biological precursors (halophilic archaea, prasinophytes, planktonic algae, etc.) during the salt deposition of the Upper Pechora Basin. Our data confirmed the predominance of hexadecylbenzene (C22) among n-alkylbenzenzenes under hypersaline environments. The presence of phytanylbenzene and phytanyltoluene was established in the rocks of the Upper Pechora salt basin. It was found that the maximum content of phytanylbenzene is correlated with elevated contents of phytane and hexadecylbenzene, which suggests their common source and allows us to consider these compounds as indicators of paleohypersalinity. The abundance of 5,7,8-trimethyl-MTTC at low concentrations of mono- and dimethyl-MTTC indicates significant input of fresh water into the evaporite basin during the deposition of the underlying rock salt horizon.

The treatment with N-methylpyrrolidone of sedimentary rocks of the Ayuvinskoye deposit allowed obtaining ash-free concentrates with different yields, depending on the Corg content in the rock. The structure of the resulting concentrates was studied by elemental analysis, thermogravimetry, and pyrolysis, followed by analysis of the products by gas chromatography-mass spectrometry. The TGA curves indicated similar structural features of the organic matter of the rocks and the concentrates obtained from them. The composition of the thermolysis products of the concentrate indicated the preferential extraction of aliphatic structures, represented by n-alkyl chains, relative to aromatic fragments, which was associated with the specific structure of the initial organic matter of solid fossil fuels.

Ðàññìîòðåíû ðåçóëüòàòû èçó÷åíèÿ àðîìàòè÷åñêèõ óãëåâîäîðîäîâ-áèîìàðêåðîâ â íåôòÿõ âåðõíåãî äåâîíà è áèòóìîèäàõ äîìàíèêîâûõ îòëîaeåíèé Òèìàíî-Ïå÷îðñêîãî áàññåéíà.Ïîêàçàíî, ÷òî ðàñïðåäåëåíèå òðèàðîìàòè÷åñêèõ ñòåðîèäîâ ñîñòàâà Ñ 26 -Ñ 28 â íåôòÿõ íåñêîëüêî îòëè÷àåòñÿ îò òàêîâîãî â áèòóìîèäàõ, ïðè ýòîì ðàñïðåäåëåíèå íàñûùåííûõ ñòåðàíîâ ñîñòàâà Ñ 27 -Ñ 29 äëÿ íåôòåé è áèòóìîèäîâ äîñòàòî÷íî áëèçêî.Êîýôôèöèåíò TA(I)/TA

The results of studies of organic matter and technological features of coal from a number of deposits of the Pechora coal basin are presented.Based on data on the composition of biomarker hydrocarbons, data on the thermal maturity of organic matter (OM) of coal are confirmed, assumptions are made about the influence of aquatic and terrigenous vegetation on the formation of the initial OM, and differences between its composition for brown coals concentrated in the southern part of the Pechora coal basin are shown, and coal of the northern areas of the basin.The work demonstrates the possibility of obtaining an ash-free concentrate -the so-called hypercoal by extraction of the initial coal with N-methylpyrrolidone at the boiling point of the solvent in high yields and the similarity of the structure of the obtained product with the structure of the organic mass of the initial coal.

Изотопный состав углерода нефтей нИжнего

Organic component in the Lower Permian salt sequence in the southern part of the Yakshinskoe deposit of the Upper Pechora potassium basin is represented by dispersed organic matter, liquid hydrocarbons in fluid inclusions in halite, as well as inclusions of bacterium, algae, spore and pollen of plants. Analysis of saturated and aromatic bitumen fractions from salts, halopelites, and clayey–silty interbeds revealed the presence of organic matter of type II and mixed type II–III. It is shown that the cover sequence and potassium bed from the southern part of the Yakshinskoe potassium–magnesium salt deposit contain autochthonous immature organic matter, whereas underlying rock salt and host rocks contain significant amount of immature allochthonous components. These migration hydrocarbons are likely immature condensates.

Óãëåâîäîðîäíûé ñîñòàâ ðÿäà îáðàçöîâ íåôòè èç îòëîaeåíèé