This paper presents the results of geochemical and petrophysical studies of the Semiluk-Mendym (Domanik) and Kynovian deposits of the Frasnian age of the Devonian system at the Romashkinskoye giant oil field of the Republic of Tatarstan. The biomarker composition of the organic matter of the rocks is shown, its catagenetic maturity and facies conditions of its formation are assessed. In addition, the composition of saturated biomarkers (alkanes, steranes, and triterpanes) of Devonian oils were studied. The correlation «oil-organic matter of rocks» was carried out for oils of the Domanik and Kynovian horizons. It is shown that the differences in the biomarker composition of oils from the Domanik and Kynovian horizons are of practical importance in the field development process, since this allows optimizing the oil production process by evaluating the contributions of oil inflows from different reservoirs. Keywords: Domanik deposits; oil geochemical research; biomarkers; alkanes; terpanes.

Studies on the conversion of organic matter of high-carbon Domanik (siliceous-clay carbonate) rock of the Romashkinskoye deposit with a mineral content C org of 7.07% in sub- and supercritical water have been carried out. It was shown that subcritical water at a temperature of 320°С and 17.0 MPa leads to a partial decomposition of the kerogenic structure, increasing the yield of bitumen from 3.12 to 3.98%, and a more complete recovery of asphaltenes and heavy C 22 -C 30 n-alkanes from the rock sample. Supercritical water at temperatures of 374 and 420°C and pressures above 24.4 MPa leads to intensive formation of hydrocarbon and inorganic gases in the processes of kerogen decomposition, destruction of aliphatic substituents from condensed heteroatomic structures of resins and asphaltenes, and the carbonate component of Domanik rock. Degradation of the organic matter of the Domanik rock is also accompanied by the formation of saturated hydrocarbons with an increased content of light C 12 -C 21 n-alkanes, and carbonaceous substances, such as carbene-carboids. Changes in the structure of asphaltenes and their paramagnetic properties were determined by the EPR method. The influence of sub- and supercritical water on phase changes in the composition of rock minerals, as well as on the yield and composition of formed gases, was revealed.

The article presents research and describes the mechanism of aerobic biodegradation of oils of various origins. The influence of degradation processes on the relative distribution of normal alkanes and isoprenoids is considered. When drawing conclusions about the type of source substance, sedimentation conditions, and maturity parameters based on biomarker correlations, it is essential to exclude the presence of biodegradation, or take into account its influence in relation to the objects under study. The practical significance of the research lies in the fact that the selectivity of oil biodegradation in terms of various effects on the ratio of isobutane/n-butane can be used to clarify the remaining reserves of oil fields.

Oils from Nizhne-Karmal (Tatarstan, Russia) and Boca de Jaruco (Cuba) reservoirs had been researched by GC-MS. Distributions of alkanes, steranes, hopanes, alkylbenzenes had been used as biomarker characteristics. Initial organic substances of both samples had been formed in sea conditions, what had proved by ratio of pristine to phytane. Lack of steranes in Cuban oil evidence about vertical migration or biodegradation processes. Anaerobic microbiological degradation had caused the absence or partial destruction of saturated hydrocarbons. The maturity of raw materials had been estimated by the ratio Ts/(Ts + Tm). Low value Aryl Isoprenoid Index (AIR) showed stability of photic zone for Nizhne-Karmal oil. Photic zone in Cuban reservoir was subjected to the mixing water column.

In this study, oil-soluble transition metal-based catalysts (Fe, Co, Ni) are proposed for catalyzing aquathermolysis reactions in steam injection process for heavy oil production to achieve in-situ upgrading of heavy oil. Their catalytic performance and possible mechanism were investigated by autoclave experiments together with a comprehensive analysis of the change in physical and chemical properties of the upgraded oil using SARA analysis, viscosity measurement, GC, GC-MS, FTIR, and 13C NMR, etc. Simultaneously, the in-situ transformation of these catalysts was also analyzed by TG-FTIR, XRD, and Mossbauer spectra, etc. to better under the possible catalytic mechanism. The results showed that the in-situ transformation of these oil soluble catalysts occurred during the thermal treatment process at 250 degrees C and 300 degrees C, and their metal-based complexes, oxide, sulfide, and sometime pure metal were in-situ generated and played a catalytic role for aquathermolysis reactions. These catalysts showed a good catalytic performance at 300 degrees C for heavy oil upgrading in reducing viscosity, increasing saturates content (especially low molecule weight alkanes), decreasing resins and asphaltenes content, removing sulfur and nitrogen, and decreasing polyaromatics content, etc. by inhibiting the condensation and recombination reactions and promoting thermal decomposition reactions of heavy components (resin, asphaltene, and polycyclic aromatics, long chain alkanes, etc.) and hydrogenation reaction. Nickle gives the best catalytic performance. The low cost and easy access together with its high catalytic activity make its wide application a great potential in catalyzing aquathermolysis reaction in steam injection process for in-situ upgrading and heavy oil recovery.

This paper discusses the results of the influences of subcritical (T = 320 °C; P = 17 MPa) and supercritical water (T = 374 °C; P = 24.6 MPa) on the yield and composition of oil hydrocarbons generated from carbonaceous–siliceous Domanic shale rocks with total organic content (Corg) of 7.07%. It was revealed that the treatment of the given shale rock in sub- and supercritical water environments resulted in the decrease of oil content due to the intensive gas formation. The content of light hydrocarbon fractions (saturated and aromatic hydrocarbons) increased at 320 °C from 33.98 to 39.63%, while at 374 °C to 48.24%. Moreover, the content of resins decreased by almost twice. Insoluble coke-like compounds such as carbene–carboids were formed due to decomposition of kerogen after supercritical water treatment. Analysis of oil hydrocarbons with FTIR method revealed a significant number of oxygen-containing compounds, which are the hydrogenolysis products of structural fragments formed after destruction of kerogen and high-molecular components of oil. The gas chromatography–mass spectroscopy (GC–MS) method was applied to present the changes in the composition of mono- and dibenzothiophenes, which indicate conversion of heavy components into lighter aromatic hydrocarbons. The specific features of transforming trace elements in rock samples, asphaltenes, and carbene–carboids were observed by using the isotopic mass-spectrometry method.

In this study, the hydrothermal upgrading (HTU) of high sulfur-content heavy oil was investigated at sub-critical (Sub-CW), near-critical (NCW) and supercritical water (SCW) conditions. Products obtained after HTU, including gases, liquid, and coke (if formed), were analyzed to understand the upgrading performance at different conditions. At Sub-CW (200, 250, and 300 degrees C), 250 degrees C is the optimum temperature where a viscosity reduction from 2073 to 1758 mPa s was achieved with a slight removal of sulfur (mainly sulfur) and the generation of a small amount of light and non-condensable hydrocarbons in gas phase (C1-C4, isoalkanes and alkenes, H2S, CO2 and H-2, etc.). At NCW (350 degrees C) and SCW (400 degrees C), heavy oil was upgraded into light oil with a significant removal of heteroatoms, an increase of saturates content, a reduction of aromatics, resins and asphaltenes contents, and a high yield of light gaseous hydrocarbons (mainly methane). Simultaneously, each SARA fraction was also greatly ameliorated: the content of light alkanes with low molecular weight in saturates was increased, diaromatics content in aromatics was increased with a reduction of polyaromatics content, aromatics-type carbon atoms in resins was increased with a decrease in aliphatic hydrocarbons. Moreover, MALDI-TOF measurements of asphaltenes show that the molecular weights of asphaltenes were reduced. All these results indicated that HTU at Sub-CW can be used for heavy oil pre-treatment (in-situ or ex-situ upgrading) considering its main effect of viscosity reduction with a small removal of heteroatoms, while HTU at NCW and SWC has a great potential in insitu and ex-situ upgrading and oil refining as it can convert heavy oil into light oil.

http://jpst.ripi.ir Journal of Petroleum Science and Technology 2018, 8(4), 49-57 © 2018 Research Institute of Petroleum Industry (RIPI) ABSTRACT The purpose of this study is the detection of lateral and vertical gradients of relative concentrations of compounds presented in oil. In addition, the detection allows us to assess potential drainage zones in a reservoir during the reservoir production by steam injection. In this paper, a new method for monitoring of steam chamber development in a 2D model was created and tested. The methodology is used to consider the total hydrocarbon fraction. In addition, the total hydrocarbon fraction has been isolated from core extracts and has been analyzed by GCMS method (TIC) for detection of various compounds and assessment of lateral and vertical gradients of their concentration in lateral. It has been found out that the ratio of 4and 1-methyldibenzothiophenes (MDBT) changes in lateral and in vertical directions. These changes are caused by biodegradation of organic matter. Also laboratory research shows that 1-MDBT/4-MDBT ratio in native reservoir rocks is stable under high temperatures and pressures and this can be easily measured by GC-MS. This measurement will allow assessment of location and direction of steam chamber propagation. In a recent work, the authors have developed a geochemical model which can be used for assessment of oil flow directions during the development of heavy oil fields by SAGD method.

We applied new novel approach based on pyrolytic gas chromatography-mass spectrometry technology (Py-GCMS) developed by Frontier Lab company (Japan) in order to get the same data as it can be acquired by using conventional core analyzer. Experimental part describes the detailed measurement procedure, temperature program and outcomes acquired by using IFP 160000 as a standard sample. We have managed to demonstrate accuracy and reproducibility of tests for the domanic source rock samples and its kerogen extracted respectively. In results of this analytical challenge we were able to get pyrograms providing the S1 (free hydrocarbons), S2 (potential hydrocarbons), Tmax (temperature at which the maximum rate of hydrocarbon generation is reached) information with level of confidence we usually could see doing conventional core analyzer tests. Some important conclusions regarding petroleum generation and thermal maturity have been made. S1 and S2 significantly decrease for kerogen samples with Tmax growth at the same time. Moreover mass spectra data of core samples pyrolizates can be collected easily to detect certain groups of compounds. Sulfur-containing compounds temperature extracted by Py-GCMS can be measured for example. Py-GCMS technology fully comply with mainstream analytical protocol for whole-rock or kerogen analysis and even more, Py-GCMS has a lot of advantages against conventional approach providing us additional valuable information about a sample.

Increasing steam-thermal methods efficiency for heavy using various catalysts is generating considerable interest in scientific research all over the world. Thus, it is worth to optimize catalyst effectiveness during their in-situ formation from oil soluble precursors using different transition metals. In this paper, a physical simulation of heavy oil catalytic aquathermolysis from the Ashalchinskoye field was carried out. The process was carried out in the presence of a hydrogen donor and a mixture of oil-soluble iron and cobalt metal tallate (1:1 weight ratio) at temperatures 250 °C and different exposure time (6 and 24 h). It was found that the most effective conditions for the thermal conversion of the oil under study are a temperature of 250 °C at 24 hours. In this case, a significant decrease in the proportion of high molecular weight components, mainly resins (by 39 %) and viscosity (about 45 %) occurs due to the course of destructive processes. At the same time, GCMS analysis of the aromatic oil fraction showed that an increase in time promotes the redistribution of mono- and polyaromatic structures.

In this article, we consider a promising method for estimating the water saturation of a super-viscous oilfield (hereinafter, SVO field) in the case of Cheremshansky oilfield, Russian Federation. A lithological description of the reservoir was carried out and gas chromatography-massspectrometry analysis of hydrocarbon fractions of core bitumoid was performed. It is shown that the ratios of certain biomarkers (methyldibenzothiophenes, 6H-Farnesol and pristane) SVO have extrema, both at the end of oil reservoir, and in the middle. Based on the fact that such dependencies indirectly indicate the distribution of water in the oil reservoir, the authors formulated the conclusion that there is no pure water reservoir (along the studied wells). Also, the authors have shown that the distribution of the 'oil-water' by measuring the gradients of concentrations of biomarkers SVO bears certain advantages and is a good addition to the classic geophysical methods.

In this article we studied a sample of Domanic rock with high kerogen content obtained from Volga-Ural oil and gas basin. A laboratory modeling of the catagenesis process was carried out in order to establish the transformation mechanism of organic matter. The composition of liquid products resulting from kerogen pyrolysis was investigated. The kerogen fragments fall in aromatic hydrocarbons fraction. Alkyltoluenes also exist in saturated hydrocarbon fractions due to alkyl substitutes. The thermal influence changes the ratios of relative content of ortho-, para- and meta-isomers. Heavy aromatic hydrocarbons content increases by increasing temperature and kerogen macroelements ratio changed under thermal effect that is an indicator for maturation process of organic matter.

The purpose of this study is to detect lateral and vertical gradients of relative concentrations of compounds presented in oil, which allows assessing potential drainage zones in the reservoir during the reservoir production by steam injection. In this research new method for monitoring of steam chamber development in 2D model was created and tested. Methodology: Total hydrocarbon fraction was isolated from core extracts and analyzed by GCMS method (TIC) for detection of various compounds and assessment of lateral and vertical gradients of their concentration in lateral. It was found that the ratio of 4- and 1-methyldibenzothiophenes (MDBT) changes in lateral and in vertical directions. These changes are caused by biodegradation of organic matter. Laboratory research shows that 1-MDBT/4-MDBT ratio in native reservoir rocks is stable under high temperatures and pressure and can be easily measured by GC-MS. This measurement will allow assessment of location and direction of steam chamber propagation. In recent work the authors have developed geochemical model which can be used for assessment of oil flow directions during the development of heavy oil fields by SAGD method.

In the near future hydrocarbons will remain the main source of energy. Now there is a growing interest in the development of the reserves of unconventional hydrocarbon resources: Shale oil and gas, heavy crude oil and natural bitumen, which world reserves are comparable to traditional. The main obstacle in the extraction of heavy crude oils is their high viscosity due to a significant content of resinous-asphaltenic compounds. The thermal-steam formation treatment creates conditions for aquathermolysis decomposition of high molecular oil components, which produces gas, as well as changes its elemental, group and fractional composition. The thermal-steam impact leads to the destruction of the least stable carbon heteroatoms with the separation of peripheral fragments from the resinousasphaltenic compounds and the formation of hydrocarbons, heteroatomic compounds, and benzene resins. Bituminous oil from Ashalchinskoye deposit (Republic of Tatarstan) is used as an object of study in the work. Molecular catalyst precursor is synthesized using the distillate tall oil as ligand former. The active catalyst’s form is generated during the thermal exposure. The experimental results show the possibility to intensify the process of insitu upgrading of high-viscosity oil in the deposit’s thermal-steam treatment. Use of the catalyst, which active form is generated in situ, can achieve reduction of resinous-asphaltenic substances, which provides an irreversible reduction in the produced oil viscosity and facilitates further transportation and processing.