pdf № 283, July

DOI: 10.19110/2221-1381-2018-7-3-9

The purpose of this paper is related to the improvement of the technique of oil and gas deposits prospecting on the complex of data of measurements of various physical fields and geological and geophysical interpretation of the results of analysis of information obtained from maps of morphological structures of the Central type. The article shows a correlation between the location of deposits of different types of hydrocarbons (gas, oil) and the morphological structures of the central type (MSCT). In the work the whole complex of various methods of research was used: the mutual correlation analysis of measurements of magnetic, gravitational fields and heat flux values, geological and tectonic features of the spatial and deep structure of morphological structures of the central type.

Keywords: morphological structures of Central type, magnetic, gravity fields, heat flow, oil-gas fields.

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DOI: 10.19110/2221-1381-2018-7-10-15

The previous unbalanced models of tectonic structure of central part of Korotaikha depression are briefly reviewed. The author's interpretation of the seismic section РС15-20689 in the light of open access geological and geophysical materials have significantly changed the previous constructions. For the first time, a balanced geological and geophysical section confirmed by structural palinspastic reconstruction, was created, which was suggested as tectonotypical.

The main zones of sole thrust in formation of the structure are: Korotaikha detachment (main regional sole thrust on plastic Upper Ordovician salt strata); Lower Permian flish floor and coal-bearing sediments of Kungurian Stage; Devonian evaporite layers in Labogeyskaya monocline.

The structural palinspastic reconstruction of Paykhoides showed that the total horizontal compression of depression structures is about 60 km. Pay-Khoy antiformal stack full-duplex structural swell, distinguished under the allochthon of Pay-Khoy structural zone, was estimated as the most perspective potentially oil-and-gas bearing macrostructure of the depression.

Keywords: tectonics, Korotaikha depression, foredeep, balanced section, palinspastic reconstruction.

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DOI: 10.19110/2221-1381-2018-7-16-27

The results of geologic-paleobotanical studies of the relief-forming Pliocene-Neopleistocene terrigenous deposits, originally divided from below upwards to moribund, morainic and overmature, are discussed. Based on the data obtained, conclusions are drawn about the geological age and landscape-climatic conditions of sedimentation, paleosolinity of the sedimentation environment. The forms and degree of fossilization of Pliocene nutlets of the species Carex cf. caespitosa L. The first detailed optical and electron-microscopic studies led to the discovery on the surface of fossils of polymineral films, a new source of geologic-paleobotanical information.

Keywords: Pliocene, Neopleistocene, terrigenous deposits, vegetation residues, fossilization of nut species Carex cf. caespitosa L., polymineral films on the fossil surface.

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DOI: 10.19110/2221-1381-2018-7-28-33

A lithological research of alluvial deposits was carried out and identified features of the granulometric and mineral composition of the Chirvino (Likhvin), Rodionovo (Shklov), Sula (Mikulino) and Byzovaya (Leningrad) alluvium. A change in the granulometric composition of alluvial deposits was established, which was associated with their facial affiliation. The sections of fossil alluvium mainly presented its fluvial facies, or, more accurately, the sedimentary shoal deposits, on the whole quite well sorted. The mineral composition of the heavy fraction of alluvial deposits indicates its formation mainly due to the material of the underlying tills, in some cases — the bedrock of the Ural and Timan mountain systems, the Chernyshev ridge, and also the rocks of the near transit, which to a large extent determined the features of the mineral alluvium associations in individual sections , as evidenced by variations in the content of epidote, amphiboles, garnets, pyrite and siderite.

Keywords: Upper Neopleistocene, Middle Neopleistocene, alluvial deposits, interglacial, granulometric composition, mineral composition, lithology.

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DOI: 10.19110/2221-1381-2018-7-34-40

Reconstructing the Holocene history of the small mammal fauna is of special value because it provides an example of the natural development of mammalian communities under the influence of climate changes. We studied 5223 teeth of small mammals from the cave sites and avian pellets in the valley of the Usa River (right tributary of the Pechora River) by standard paleontological methods. Radiocarbon dating of fossil assemblages was made by ¹⁴C AMS method. Localities are of zoogenic origin with numerous remains of vertebrates. As a result of the study, three phases of the development of micromammalian fauna in the Chernyshev’s ridge were described: of Boreal, Subboreal and modern periods. During the Boreal, when the territory of the north of Eastern Europe was occupied by taiga forests, fauna of small mammals comprised forest and intrazonal species approximately in equal proportions, and only 10—13 % of all remains were represented by tundra and steppe species. It was revealed that during the Subboreal period of the Holocene mammalian fauna consisted of inhabitants of spruce and pine forests. Modern rodent fauna of the Chernyshev’s ridge is inhabited only by taiga species.

Keywords: small mammals, Holocene, Chernyshev’s ridge, north-eastern part of European Russia.

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DOI: 10.19110/2221-1381-2018-7-41-48

In the old oil-producing regions, the content of hard-to-recover reserves increases due to intensive development of active reserves. The problem of developing heavy oil deposits is extremely relevant for Russia, but industrial development is not going fast enough due to their low profitability. The article is devoted to the history of the development of the Yarega heavy oil field, which was discovered in 1932, and since 1939 it has been mining. The oil deposit is confined to quartz sandstones of Devonian age. A feature of the reservoir, containing the oil deposit, is that it contains industrial reserves of titanium. Therefore, the uniqueness of the Yaregа field lies not only in the mine method of extracting heavy high-viscosity oil, but also in the integrated development of minerals that, at the whim of nature, are combined in one facility.

Keywords: oil reserves, high-viscosity oil, oil development, oil recovery factor, steam-assisted gravity drainage.

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DOI: 10.19110/2221-1381-2018-7-49-52

The materials, presented in this paper, inform about the most interesting scientific and engineering solutions created for Vuktyl conditions from 1966 to 2018.

Taking into account the fact that most of the national oil and gas condensate fields are operated in the depletion regime, resulted in the extraction of condensate no more than 40 %, the research of Vuktyl historical experience becomes invaluable to solve problems of the fields in the final stage of operation.

Keywords: Vuktyl, VNIIGAZ, gas, condensate, exploration, technologies, stimulation, production, well, experiment.

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