A geochemical study was carried out on oil and gas samples from the Verkhnechonskoye field, located on the Nepa‐Botuoba Anteclise in the central‐southern part of the Siberian Platform. The goal of the study was to distinguish between fluids derived from the V 10‐13 and B 12 reservoir units in the Vendian (Neoproterozoic) Katanga and Nepa Formations and to identify the producing reservoir using geochemical data. The results of analyses of 12 oil and 13 associated gas samples from the two reservoirs showed that all the fluids have similar geochemical properties including: low Pr/Ph ratios (0.78‐1.00); a predominance of C 29 over C 27 and C 28 steranes; a predominance of odd‐numbered C 21 ‐C 25 n‐alkylbenzenes over their even‐numbered homologues; the presence of 12‐ and 13‐methylalkanes; and a high relative abundance of tricyclic terpanes (cheilantanes). All these properties are consistent with those of the properties of petroleum from other fields on the Siberian Platform. The molecular and stable carbon isotope compositions of the oils and gases suggest that they were derived from marine organic matter with a high algal input deposited under reducing conditions. To date, specific source rocks which generated the oil and gas present at fields on the Nepa‐Botuaoba Anteclise have not conclusively been identified, but potential candidates include the Upper Riphean Iremeken and Ayan Formations and more probably the Vendian Zherbinskaya, Seralakh, Vanavara and Nepa Formations. The second part of the study demonstrates the application to reservoir geochemistry of C 3‐ and C 4‐ alkylbenzene compounds together with more conventional biomarkers. Key parameters were selected using statistical processing and displayed in graphic profiles. These profiles allowed the oil and gas samples to be classified according to the reservoir from which they were derived based on their geochemical properties. Parameters based on C 3‐ and C 4‐ alkylbenzene compounds were most effective in discriminating between oils from the two reservoirs. In addition, a new parameter is proposed based on the contents of 1‐methyl‐3‐isopropylbenzene, 1‐methyl‐2‐isopropylbenzene and 1‐methyl‐2‐propylbenzene; this parameter correlates closely with the pristane/phytane ratio and can be used as an additional indicator of the level of oxicity in the source rock depositional environment.

Для цели построения бассейновой модели выполнен и проанализирован комплекс лабораторных исследований рифейских пород и нефтей методами органической геохимии, в частности, удалось сравнить параметры органического вещества верхнерифейской ирэмэкэнской углеродистой пачки и нефтей по углеводородам-биомаркерам. Анализ полученных данных хроматомасс-спектрометрии показал неординарность ирэмэкэнской толщи и нефтей, полученных из нее, что проявляется в низком содержании хейлантанов и стеранов, групповом составе экстрактов. Обогащенные ОВ отложения ирэмэкэнской толщи верхнего рифея с превосходным нефтегазогенерационным потенциалом в пределах Камовского свода достигли пика нефтегенерации, вероятно, только в самой погруженной части Мадринского прогиба, что не позволило бы полностью заполнить ловушки. Распределение трициклических терпанов в битумоидах пород в изученных скважинах указывает на недостаточную зрелось ОВ ирэмэкэнской толщи, однако в самых погруженных зонах Камовского свода и прилегающих территорий, генерация несомненно происходила из ОВ ирэмэкэнской толщи и в нефтях из верхнеирэмэкэнской подтолщи мы это отмечаем на Куюмбинском и Терско-Камовском месторождениях. A complex of laboratory studies of Riphean rocks and oils was carried out by the organic-geochemistry methods to construct a basin model for the Kamo arch of the Baikit anteclise of the Siberian craton. We compared the parameters of the organic matter (OM) and oils of the Upper Riphean Iremeken carbonaceous member by biomarker hydrocarbons. Analysis of the obtained chromatography–mass spectrometry data showed an unordinary group hydrocarbon composition of extracts from the OM and oils and low contents of cheilanthanes and steranes in them. Within the Kamo arch, the Upper Riphean Iremeken OM-enriched deposits with a high petroleum potential might have reached the peak of petroleum generation only in the deepest part of the Madra trough; thus, the traps could not be completely filled with oil. The distribution of tricyclic terpanes in the rock bitumens from the studied wells testifies to immature OM in the Iremeken Formation. However, in the most submerged zones of the Kamo arch and in the adjacent areas, oil was generated from the OM of the Iremeken Formation. This is evidenced by the oils of the Upper Iremeken Subformation in the Kuyumbinskoe field and the Ter'-Kamo license area.

complex of laboratory studies of Riphean rocks and oils was carried out by the organic-geochemistry methods to construct a basin model for the Kamo arch of the Baikit anteclise of the Siberian craton. We compared the parameters of the organic matter (OM) and oils of the Upper Riphean Iremeken carbonaceous member by biomarker hydrocarbons. Analysis of the obtained chromatography-mass spectrometry data showed an unordinary group hydrocarbon composition of extracts from the OM and oils and low contents of cheilanthanes and steranes in them. Within the Kamo arch, the Upper Riphean Iremeken OM-enriched deposits with a high petroleum potential might have reached the peak of petroleum generation only in the deepest part of the Madra trough; thus, the traps could not be completely filled with oil. The distribution of tricyclic terpanes in the rock bitumens from the studied wells testifies to immature OM in the Iremeken Formation. However, in the most submerged zones of the Kamo arch and in the adjacent areas, oil was generated from the OM of the Iremeken Formation. This is evidenced by the oils of the Upper Iremeken Subformation in the Kuyumbinskoe field and the Ter'-Kamo license area.

-The paper presents original results of comprehensive geochemical studies of samples of oils, condensates, gases, core, and cuttings from wells drilled in the north of Western Siberia. The studies involved chromatographic and mass spectrometric determinations of the molecular and isotopic composition of the oils, gases, condensates, and rock extracts. Analysis of the results, considered together with literature data, made it possible to draw conclusions regarding the source of the hydrocarbons and the mechanism of formation of their accumulations. Information on the molecular and isotopic composition of the fluids and the distribution of their accumulations and fields in the sedimentary cover shows that most of them are of polychronic and polygenic origin. Features of the molecular and isotopic composition of the fluids make it possible to evaluate the contribution of various sources to the formation of hydrocarbon accumulations. The composition of their liquid component was formed as a result of the generation of hydrocarbons by the organic matter of Jurassic source rocks. The Lower and Middle Jurassic rocks with non-marine organic matter also made a significant contribution to the formation of the gas component of deposits in the north of Western Siberia, whereas the Cretaceous rocks generated only dry gas and were likely the main source of gas for the giant fields, whose methane has a light carbon isotope composition. The use of the isotopic composition of carbon in combination with molecular parameters makes it possible to clarify the conditions under which a particular field was formed and to elucidate the migration pathways and distances of hydrocarbon fluids to their accumulation sites.

A suite of geochemical studies on core and petroleum samples from the south of the Tyumen region (Western Siberia Basin, Russia) has been performed. Pyrolysis data from rock samples of Lower Cretaceous and Jurassic sediments establish the presence of at least four potential source rock intervals in the study area. Of these, the Upper Jurassic Bazhenov interval hosting marine organic matter has the greatest potential for oil and gas generation. The other identified source intervals are of lower quality and do not have a potential for generating significant amounts of liquid petroleum due to the terrestrial nature of the organic matter. A detailed study of petroleum and source rock extract data confirms that the Bazhenov source interval is the main source of all reservoired petroleum found in the region. Lower Cretaceous petroleum deposits are found at distances up to 100 km from the mapped Bazhenov kitchen areas. Petroleum deposits in Upper Jurassic reservoirs have been generated in local kitchens or have migrated over short distances only (10-20 km). The largest regional spread is seen in Bazhenovgenerated petroleum in Middle Jurassic Tyumen reservoirs, which are found in deposits along migration routes from the kitchen areas towards the south and which can reach up to 150-200 km. (c) 2020 Elsevier Ltd. All rights reserved.

Summary The work is devoted to geochemical studies of Paleozoic genesis oils in the south-east of Western Siberia. The work included studies of molecular and isotopic composition of 120 samples of Paleozoic oils from 15 fields. The study of oils was done by gas chromatography–mass spectrometry method in tandem with isotope mass spectrometry for more accurate interpretation of the results. Based on the results of molecular and isotopic analyses, three Paleozoic oil families were identified, the differences in which are due to sedimentation conditions of the oil-material rocks involved in their generation. The aryl isoprenoids have been identified in the Paleozoic oils. The presence of these compounds in the composition of oils indicates that the accumulation of organic matter of oil-material rocks occurred in conditions of anoxia of the photonic layer. The information obtained on the genetic type of Paleozoic oils and the identification of different groups among them indicate that at least three different intra Paleozoic sources were involved in their generation.

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The molecular and isotopic composition of an extract from the rocks of the Bazhenov Formation in the southeast part of Western Siberia, oils that are genetically related to this formation, and products of hydrous pyrolysis of the organic matter of oil shale (Middle Volgian) of the East European Platform were studied. Common features and differences in their molecular composition were shown. The carbon isotope composition for C14–C30n-alkanes was determined for the first time; a negative isotope anomaly was revealed for C26n-alkane in all samples studied. It was concluded that in spite of the geographical distance, specific biota was revealed in the Volga Basin. This biota conditioned an isotopic indicator, which is genetically significant.

Проведены исследования физико-химических свойств жидких продуктов, полученных в результате конверсии пропан-бутановой фракции и неподготовленных попутных нефтяных газов в условиях барьерного разряда. Показано, что жидкие продукты, получаемые при конверсии попутного нефтяного газа, обладают более высокой плотностью, вязкостью по сравнению с продуктами, получаемыми при конверсии пропан-бутановой фракции. Также показано, что при увеличении содержания в исходном газе доли метана снижается выход жидких углеводородов с единицы объема исходного газа. Установлено, что при совместной конверсии углеводородов с парами воды в продуктах реакции обнаруживаются спирты, среди которых, как и для углеводородов, характерно преобладание структур с разветвленным углеродным скелетом. На основании данных по компонентному составу образующихся продуктов и проведенных расчетов сделаны некоторые предположения о возможном механизме бескислородной конверсии углеводородов в условиях барьерного разряда.

Disadvantages, concerning the extraction of natural gas with a touch of sulfur-containing compounds, are revealed. It is noted that the existing GOST on determination of sulfur-containing compounds in natural and liquefied gas can only determine of hydrogen sulfide and the total content of mercaptan sulfur. An attempt was made by the example of one of the fields to minimize the influence of extraction conditions on the content of sulfur-containing compounds in petroleum gas.

Abstract Experimental data on natural gas hydrocarbons conversion in the low-temperature plasma are provided. The impact of different process parameters (pulse rate, volumetric gas throughput) upon gas hydrocarbons conversion degree is examined. In order to increase the liquid hydrocarbon output and decrease reactor size, the multitubular composition of plasma-chemical reactor was applied. Positive results demonstrated the possibility of using multitubular reactors when working with high frequencies (200 Hz and higher) in order to obtain higher hydrocarbons from lower methane homologs.