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Vol 25, No 3 (2023)
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EDITOR-IN-CHIEF’S COLUMN

RESEARCH ARTICLES

4-12 148
Abstract

In the article, based on a relatively deep-water clinoform model of the Achimov strata structure based on the analysis of sedimentological processes and 3D seismic data, the characteristics of the morphological types of clinoform formations, structural features and sedimentation of the Lower Cretaceous deposits in the zone of counter clinoforms are given, a new type of hydrocarbon traps is identified within this area, their seismic images are presented.
It is noted that in the zone of east-dip clinoforms (the Ural source of demolition), it is necessary to evaluate the prospects for oil and gas potential of the section based on the analysis of seismic and gravity survey and logging data, in order to predict fractured reservoirs.

13-26 157
Abstract

In Western Siberia, the zone of abnormally high reservoir pressures (AHRP) covers an area of more than 500 thousand km2 in the north of the basin. It begins with a clay layer above the Achimov formation of Neocomian sandy-silty formation, covers the Achimov formation, Upper–Lower Jurassic, Triassic and partially Paleozoic and is subject to tectonic control, which indicates the deep origin of this phenomenon. Gas-pressure, or gas-dynamic, theory of AHRP, proposed by K.A. Anikiev in the 70s of the 20th century, allows us to assess the prospects for oil and gas content of the AHRP zone higher than it is commonly-accepted.
Analysis of the results of previously completed geological exploration work on the deep horizons of the Yamalo-Nenets Autonomous Okrug indicates that their relatively low efficiency (50–60%) is associated with the insufficiently high quality of well operations, primarily cementing, which is also due to the influence of AHRP. In all wells drilled to deep horizons, direct signs of oil and gas potential were obtained and cementing defects were identified.
It is concluded that deep fluid-dynamic processes (active, pressure degassing of the Earth’s interior) are responsible both for the saturation of reservoir rocks with hydrocarbons and for the dynamics of their filling (ultra-high pressures and velocities), which determine the main characteristics of reservoir rocks. Recognition of a deep source of hydrocarbons will not only make it possible to fundamentally increase the resource base of the AHRP zone, but will also require a revision of ideas about the formation and structure of hydrocarbon deposits in this zone and the petrophysical substantiation of their models. However, to realize the unique hydrocarbon potential of the AHRP zone, it is necessary, first of all, to improve the quality of deep wells construction and appropriate information content.

27-33 175
Abstract

The sequence stratigraphic models for the clinoform part of the section in the territory studied by production drilling within the Nadym-Pur oil and gas region of Western Siberia are constructed. The purpose of study was to identify patterns in the distribution of reservoir properties of the Achimov objects and substantiate a systematic approach to the correlation of reflecting horizons. The main task is to identify the characteristic features of systemic tracts based on core data from a well-studied field. To solve the problem, a classification of sediments studied by core in wells was carried out within the framework of a sequence model. To confirm theoretical concepts about the formation of improved reservoir zones in system tracts, an analysis of filtration and capacitance parameters (porosity, permeability) was performed. There is the relationship between the reservoir properties and the type of system tract in which the deposits were formed. The seismic section requires the interpretation according to the principles of sequence stratigraphy, and criteria for tracing reflecting horizons. An algorithm for constructing a model is proposed that provides a forecast of zones with improved reservoir properties. A number of advantages for the unsystematic approach to correlating reflecting horizons are given.

34-39 206
Abstract

This work is devoted to the peculiarities of sedimentation and geological structure of clinoform deposits of the Yarudeisky megaswell (Western Siberia). The main feature of the clinoforms under consideration is that the sediments are confined to the marginal regional clinocyclite of the western dip of the area of oncoming clinoforms, formed in relatively shallow sea conditions and differing from deep-sea clinoforms by pinching out not onto the Bazhenov formation or the early underlying clinoforms of the western dip, but by stopping their spread along the path of movement of the oncoming clinoforms eastern dip. The study of the counter clinoforms of the Yarudeisky megaswell is based on a regional analysis of the structure of cross-layered deposits in conditions of extremely poor knowledge of the study area. Within the framework of western dipping clinoforms, possible oil and gas potential prospects for the Achimov complex within the boundaries of the Yarudeisky megaswell are identified.
As a result of the analysis of geological and geophysical data, the boundaries of the distribution of opposing clinoform complexes in the study area were determined. The existing paleo-geomorphological conditions that contribute to the accumulation of sandstone with improved properties in the designated seismic complexes are presented. The fields of the Nadym oil and gas bearing region with the proven productivity of the Neocomian clinoform complex are indicated, which confirms the oil and gas potential of the region and suggests favorable conditions for the accumulation of hydrocarbons in the study area.

40-48 300
Abstract

In order to clarify the structure of promising oil and gas objects in the South Tambey field (Western Siberia), an integrated approach to the study of Achimov deposits has been developed. The oil and gas potential level includes layers from PK1 to Yu9 at depths from 1000 to 4000 meters. Despite the fifty-year history of drilling wells in the area, the Achimov objects are currently poorly explored in the study area and may have significant potential for development. The purpose of this work was to clarify the geological structure of the Achimov deposits, which became possible thanks to the acquisition of new geological exploration data during the study of the underlying Jurassic complex. CDP 3D seismic exploration work was completed using a modern full-azimuth observation system, and active drilling of exploration wells for Jurassic deposits in the slope parts of the main structures began. The objectives of the study were the interpretation of a 3D seismic cube covering most of the area of the site, seismic geological linking of data from the Achimov interval of the field with neighboring areas, including using the sequence stratigraphy method, accounting for the results of drilling wells for the pilot development of the Jurassic complex and the transit fund of prospecting and exploration wells, as well as the inclusion of the results of a petrophysical model in a first approximation for the Achimov reservoir interval of the South Tambey field. The results of full-azimuth CDP 3D seismic surveys made it possible to obtain reliable correlations between well data and seismic data, including analysis of AVO attributes (Amplitude Variation with Offset). Based on sequence stratigraphic analysis, the stratification of the section was clarified, correlation with neighboring territories was made, and a conceptual model of the clinoform complex was created. For each layer, system tracts within the sequences were determined. There is strong relationship existing between the formation conditions, geometry of objects and reservoir properties.

49-56 121
Abstract

A modern seismic interpretation of coastalcontinental deposits in the Jurassic complex of one of the fields in the north of the West Siberian Oil and Gas Province, including simultaneous stochastic inversion of seismic data was performed. The main object of the study was the interval of the group of J2 reservoirs. Petro-elastic modeling was carried out on the project. Modelling includes six wells with geophysical well logs. Feasibility study shows possibility of predicting lithology by stochastic inversion. In addition, optimal parametrization of elastic properties was determined to separate water-saturated and gas-saturated reservoirs from clay deposits. Interpretation of well and seismic data, as well as the results of stochastic inversion, made it possible to identify play zones in target interval. Probability cubes of gas-saturated reservoirs, made it possible to map the lenticular structure of the reservoirs and substantiate hydrodynamic barriers between individual gas plays.

57-64 135
Abstract

The paper presents the results of a comprehensive interpretation showing the effective way to integrate seismic data into a three-dimensional geological model. Stochastic inversion was used to increase the reliability of forecasts of productive thicknesses. A comprehensive interpretation of the geological and geophysical information of the Yu2 1 formation deposits of the Malyshevskaya formation was carried out, including sedimentological analysis of core data, petroelastic modeling of well logging curves for the purposes of stochastic inversion and stochastic inversion of seismic data. An areal forecast of sedimentation environments (facies) was carried out. The resulting three-dimensional geological model, in more detail, compared to the model without taking into account the spatial seismic forecast, emphasizes the heterogeneity of the distribution of properties in the geological environment, which is especially important when planning production drilling with horizontal wells.

65-74 164
Abstract

A comprehensive analysis has been conducted on the geological structure of the entire Jurassic interval within the southwestern part of the South Taymyr Monocline, which has allowed a more precise understanding of the structure of the Khabei gas field and the identification of prospective objects of similar geological pattern. The study utilized CDP 2D seismic data, covering a total length of 7835 kilometers, as well as results from exploratory and appraisal drilling. Based on visual analysis of temporal cross-sections, an assumption has been made regarding the correlation between reservoir development zones and paleo-channel systems of the Lower-Middle Jurassic deposits. In order to identify and locate such systems, an analysis of temporal cross-sections, maps of total Jurassic deposit thickness, and maps of dynamic attributes were conducted. As a result, areas of development of large paleo-channel systems (paleo-valleys) within the South Taymyr Monocline have been delineated through integration. These identified zones are characterized by relatively shallow burial depths of up to 2.5 km, the absence of abnormally high reservoir pressures (AHBP), and comparably high filtrationcapacity properties for Jurassic reservoirs (porosity – 22%, permeability – 25–50 mD).
However, considering the complexity of these objects’ structures and the uncertainties caused by the low degree of geological-geophysical exploration in the study area, it is recommended to conduct additional seismic surveys (CDP 3D) to maturate the objects for exploration drilling.

75-81 174
Abstract

The article is devoted to the development of a methodology for predicting the properties of Achimov reservoirs based on cause-and-effect relationships such as the source of shelf sedimentary material, the geometry of clinoforms and the distance of alluvial fans to the slope. The technique was developed on the basis of physical laws, namely the conditions of disturbance of the gravitational equilibrium of sediments on the shelf edge – the moment of the beginning of the removal of sedimentary material and the process of cone formation caused by the deposition (braking) of sediments on the bottom of the basin. The methodology includes two stages for step-by-step theoretical justification and ease of understanding. At the first stage, the problem of disturbing the gravitational equilibrium of shelf sediments depending on the geometry of the clinoforms is solved. At the second stage, the problem of dependence of the distance of the blades on the slope and the properties of promising objects is considered. Based on theoretical concepts, the main conclusions about the dependence of the characteristics of alluvial fans (properties and volume of sandstone) on the geometric parameters of clinoforms and on the distance to the slope are outlined, and a complex parameter characterizing the properties of promising objects is derived. The methodology developed by the author makes it possible to predict, compare and rank Achimov objects according to their prospects both within one formation and as a whole in one or several fields.

82-88 163
Abstract

The issues of rational subsurface use, technological and economic reasons for non-fulfillment of project documentation decisions and their consequences at hydrocarbon deposits are considered. The change in oil recovery coefficients in the country over a seven-year period by reserve categories is given. Proposals are made to reduce the risks from inefficient development of subsurface resources in modern conditions.

GEOLOGICAL-GEOCHEMICAL RESEARCH, PROSPECTING, EXPLORATION AND DEVELOPMENT OF HYDROCARBON FIELDS

95-110 147
Abstract

The question of the genesis of the anomalous Bazhen-Achimov zones remains to be one of the most controversial problems in Western Siberia. By now, about dozen hypotheses of the sedimentary environment of this specific formation have been proposed. However, none of these hypotheses is generally accepted. All hypotheses have been classified by genesis and their critical analysis is given in the article. The solution is closely related with experience of the geological exploration works, since the prospects of oil and gas are associated with these deposits. The article highlights the key features of the structure of the anomalous section’s zones based on drilling and seismic data. The classification of the hypotheses is given and the features of sedimentation in the Bazhenov and Achimov times are highlighted. An accumulated data has allowed us to substantiate the olistostromous genesis of the anomalous section. Based on a set of data, including paleogeographic, sedimentological, paleotectonic reconstructions, a principal detailed model of the sedimentary environment of olistostromes is proposed for the first time. The proposed model seems to be the most logical, supported by the actual data known to date, is the most universal and fits into the paleogeographic situation and tectonic regime that prevailed in the Achimov time.

111-118 265
Abstract

The main tool for increasing of oil reserves are exploration works. Improving the scientific and technical support for exploration is a priority task for the oil industry. The article deals with the development of technology for prospecting and exploration of hydrocarbon deposits in the Pre-Jurassic basement rocks of Western Siberian oil and gas province, as well as approaches to improving the reliability of mapping prospective zones using seismic data. Using the example of the Sredne-Nazymskoye field, the seismogeological aspects of the forecast of oil and gas potential of the Pre-Jurassic complex and the main directions for reducing the uncertainties of the geological structure are shown.

119-128 140
Abstract

The evolution of the elemental composition of dispersed organic matter (DOM) heterocyclic components during catagenesis was traced via studying samples from the Tyumen (SG-6) and Srednevylyuy-27 (SV-27) super-deep wells of Siberia. During mesocatagenesis, the composition of terrigenous DOM asphaltenes and resins undergoes directed changes: a decrease in hydrogen and oxygen content, enrichment with carbon, and graphitization of the structure. During apocatagenesis, due to high-temperature destruction, on the one hand, there is a condensation of individual blocks of asphaltenes and their transition to an insoluble form (formation of epiasphaltenic kerogens – EPAK). On the other hand, the lighter part of the asphaltenes goes into the formation of hydrocarbons and gas formation – a relative increase in the concentration of the former in % by mass of residual bitumoids is noted, as well as structural redistributions within benzene and spirit-benzene resins. In all studied parameters of the elemental composition, a symmetrical (unidirectional) transformation of resinous and asphaltene components of bitumoids from the SG-6 and SV-27 wells under harsh thermobaric conditions is noted. The obtained results should be taken into account when predicting new oil and gas accumulation zones in deep-laid horizons.

129-139 201
Abstract

Stabilization of oil production at the level of 215–220 million tons/year, as well as its subsequent growth, is a priority task for the enterprises of the fuel and energy complex of Khanty-Mansi Autonomous Okrug – Yugra (KhMAO – Yugra). It is impossible to achieve this without the active implementation of the most effective modern technologies for enhanced oil recovery. This article aims to analyze the methods of enhanced oil recovery and and oil production stimulation methods (EOR and PS) used at the KhMAO – Yugra fields on an industrial scale, their features and their contribution to additional oil production from 2001 to 2021.
The article describes such technologies as sidetracking (STB), physical and chemical methods (FCM), hydraulic fracturing (HF), bottom-hole treatment (BHT), hydrodynamic methods (HDM), horizontal well drilling (SHD), as well as other geological and technical measures (GTM) aimed at optimizing well operation (other methods (OM)). The study showed that FCM, BHT and other well interventions became the most used. The share of additional oil produced through the use of EOR and PS has doubled since 2013: 8% in 2013, 16.2% in 2021. Hydraulic fracturing, deep drilling and sidetracking showed the highest efficiency. All this led to the stabilization of the annual oil production in KhMAO – Yugra and even to its growth in 2021.
The use of enhanced oil recovery methods on a nonalternative basis in developed fields is especially important, because the share of hard-to-recover reserves is high and reaches 80% for some companies in the Khanty-Mansi Autonomous Okrug – Yugra. For such fields, it is necessary to strengthen scientific research in the field of substantiation of optimal conditions for well construction, as well as the operation of development systems.

140-145 173
Abstract

The majority of reserves of small oil companies of the Republic of Tatarstan are represented by carbonate reservoirs with low filtration and capacitance properties, low reservoir pressures and high oil viscosity. All this leads to a rapid decrease and a low level of current oil flows. The Akan oil field of Predpriyatie Kara Altyn CJSC is one of the examples. Thermal methods are considered as the most effective technologies for deposits with high-viscosity oil. According to the results of laboratory study of various variants of thermal methods and geological and hydrodynamic modeling, the steam-cyclic method of development was determined as the most effective at the Akan field. Two producing directional wells and two horizontal wells have been selected for experimental work on steam injection. The article considers the downhole equipment used for injection heat carrier, describes the process of steam injection with the dynamics of controlled parameters, production indicators and efficiency after heat treatment of wells. Conclusions are presented for the completed works on wells.

146-150 154
Abstract

Waterflooding of low-permeable reservoirs with high pressure is often accompanied by formation of induced fracture. The positive side of this process is an injectivity increase and oil production rise. However, when these fractures approach producing wells, an early water breakthrough occurs, and high productivity channels are formed between the injection and producing wells.
The technology of fracture clogging, for example, by suspension composition injection into an injection well, allows reducing the length of the fracture. The paper considers the problem of the fracture size reducing process on the waterflood sweep efficiency. The example of a reverse five–point waterflood pattern was investigated. In the basic calculation run, fracture length was constant during all process. The run with transformable fracture length is compared with the basic one.
The results of calculations showed that the process of waterflooding after fracture impact could be divided into the following stages. The first one, which follows immediately after the fracture clogging, demonstrates a water cut decrease and an oil production rate increase. The second, in which the oil production declines below the base variant. On the third stage, there is a low, but long-term increase in oil production due to increased waterflood sweep efficiency. The authors established that monitoring of induced fractures length is relevant, since timely fractures clogging allows to increase oil production after the well treatment and to incline the oil recovery coefficient through increasing waterflood sweep efficiency.

151-162 166
Abstract

A technique for monitoring of a production well rate dynamics based on the results of long-term temperature measurements in the wellbore at a certain depth which is significantly higher than the productive formation in real time is presented. The proposed analytical approaches for the well rate evaluation are based on the classical temperature behavior in the intervals of liquid and gas movement along the wellbore at a relatively far from the target formations. The temperature gradient in such intervals practically does not change with time and is close to geothermal, regardless of whether the inflow or injection is stable over time, or the well is in an unstable and cyclic production. It makes possible to find a relationship between the temperature change and heat flux density on the wellbore with simple and clear analytical approach, and to associate the heat flux density dynamics with the flow rate of the fluid moving along the wellbore. The main novelty of the presented publication is the justification of temperature deconvolution application for well rate changes vs time evaluation on a substantially non-stationary well production or injection conditions. The presented approach of permanent temperature monitoring interpretation is applicable not only for cases of step well rate changes, but also for cases of gradual well rate changes vs time. A wide range of measuring sensors can be used for presented approach implementation, including permanent fiber-based distributed along the length of the wellbore systems.

GEOLOGICAL AND MINERALOGICAL RESEARCH, PROSPECTING AND EXPLORATION OF SOLID MINERAL DEPOSITS

163-174 128
Abstract

The two largest deposits of Russia – Yaregskoye and Pizhemskoye belong to the same genetic type; hydrothermal-metamorphic indigenous deposits. They are located in the same Timan structure at a distance of no more than 230 km from each other. According to the total approved reserves and forecast resources of titanium dioxide, they are approaching 60% of the all-Russian and will form the basis of industrial titanium raw materials used in Russia in the near future. In the interests of technological mineralogy, morphological features, internal structure, chemical composition of grains of the two main titanium mineral phases ‒ leucoxene and pseudorutile, TiO2 polymorphs, as well as the composition of mineral microinclusions in these phases have been studied in detail. The compositions of all mineral phases in polished preparations of leucoxene and pseudorutile were analyzed by SEM-EDS method at the Institute of Geology and Geochronology of the Precambrian of the RAS, 147 chemical analyses were obtained at the point (3 µk) and many images of polished grains of anatase, leucoxene and pseudorutile were scanned over the area (20×20 µk). In the leucoxene grains themselves, 12 mineral phases were diagnosed and characterized in the form of inclusions: pseudorutile, rutile, anatase, quartz, hydromuscovite-illite, kaolinite, siderite, zircon, xenotime, pyrite, florencite, monazite and kularite. TiO2 polymorphs are verified by Raman spectroscopy and X-ray diffraction analysis. New evidence has been obtained that the transformation of ilmenite into leucoxene occurs hydrothermally through intermediate phases ‒ Fe-rutile and pseudorutile; the enlargement of rutile crystals in the leucoxene grain itself is shown; the presence of secondary crystals of siderite, florencite and others inside the studied grains.

175-190 110
Abstract

Detailed mineralogical and geochemical studies of Ti-Fe oxides from gabbroids of the Nauruz and Utlyktash post-subductional complexes, West Magnitogorsk Zone, South Urals, have been carried out. The polygenic nature of Ti-Fe mineralization in Nauruz sill, Utlyktash layered lopolith and Uraz intrusion rocks has been established. The Nauruz massif is dominated by titanomagnetite, which crystallized both from the Ti-Fe-oxide liquid at the early magmatic stage and from the residual Ti-Fe-enriched silicate melt at the intermediate and late magmatic stages (~970–800°C). The most rich in Ti-Fe oxides (Fe2 O3 * up to 20.1 wt %, TiO2 up to 1.6 wt %, and V up to 430 ppm) is the middle zone of the sill associated with intrusion of magma enriched in orthopyroxene phenocrysts. Both titanomagnetite and ilmenite are widespread in the Utlyktash lopolith, forming the richest accumulations in the lower part of the massif (Fe2 O3 * up to 18.1 wt %, TiO2 up to 2.9 wt %, and V up to 545 g/t) due to gravitational settling of crystallizing phases. The gabbroids of the Uraz intrusion are similar in mineral and chemical composition, but differ from the Utlyktash lopolith in the patterns of formation of Ti-Fe mineralization, which requires a special study. In general, the geological settings for the formation of the Nauruz sill and Utlyktash lopolith are quite favorable for the formation of economic Fe-Ti ores.

191-197 133
Abstract

The article identifies the problem of the need to take into account micro- (1 mm to 0.12 microns) and nanoscale (<0.12 microns) gold in placers and weathering crusts in order to increase the objectivity of their and eroded ore objects potential assesment. The results of technological studies of gold-bearing deluvial deposits in the valley of the Adamikha river basin (Amur region) are presented. A quantitative assessment of the content of micro- and nanogold by fractions of loose material was made. It was found that in the studied sample of such material (weighing 50 kg), the major part (78%) refers to native gold with a dimension of < 0.12 microns. Including 0.1% is in concentrator minerals, and 3.5% of the fraction (<3 microns), probably colloidal, is in technical solutions of wet sieve. Moreover, 3/4 of the total amount (18% visible and 57% invisible) of gold is concentrated in the fraction (1–0.5 mm). It is established that, taking into account the free invisible gold, the resources of the precious metal of the object under study increase by 3.4 times. The possibility of a more objective quantitative assessment of the Au potential of promising areas, taking into account the content of fine gold, is shown. Possible ways of solving the problem of a more reliable assessment of geological reserves and estimation of forecast gold resources, taking into account the knowledge of the quantities of micro- and nanoscale fractions, are proposed. The authors believe that studies of the forms of allocation and distribution, including invisible (<0.12 microns) gold in placers and weathering crusts will contribute to a more correct assessment of the studied gold-bearing objects and territories with the possibility of increasing the real resource potential of the precious metal in the region.

198-207 92
Abstract

The gold-placer deposit of Pokrovsky-Verny streams is formed on the southern slope of Belaya Gora (Khabarovsk Krai), where streams drain gold formations of the same-name deposit. The gold content in the waste dumps of past years often reaches commercial concentrations, which allows to be re-processed them and some of the gold goes back into the dumps. The field formed by ore and alluvial formations is a complex volcanic structure with a concentric-zone structure underlined by faults. At the initial stage of research, the goal was to determine the content of the precious metal in gravity concentrate samples from the placers, the study of the mineralogical and technological characteristics of gold going into dumps. 135 gold grains ranging in size from 10–15 µm to 3 mm were studied using an electron scanning microscope. Six main species were distinguished by composition and morphology: high-grade in the form of isometric crystals; aggregates of gold crystals with 0–29% silver admixture; dendrites with up to 41% silver admixture; grayish gold and silver amalgams; loose weishanite (Au,Ag)3 Hg2 formations of gray color; aggregates of ore-bearing and nonmetalliferous minerals with gold, in which the precious metal is less than half the grain. All gold grains have a flattened shape, variably contain inclusions of clay minerals, quartz, hematite, ilmenite, magnetite, limonite. Grains of native metals and intermetallic compounds are isolated in mineral association with gold. The revealed features of gold show that the formation of the precious metal is associated with hypogenic and epithermal processes, as well as with fluid emanations coming through late deep faults. Effective gold recovery requires several stages mineral processing.

208-215 143
Abstract

The findings of platinum group metal mineralization (PGM) and the distribution of platinum group elements (PGE) in lherzolites of the Northern Kraka massif are described. The total contents of PGE are approximately two orders of magnitude lower than those in chondrite and are close to pyrolite, relative to which the studied lherzolites are enriched in Pd and depleted in Ru. In segregations of PGMs, the presence of all PGEs (except rhodium) in various proportions was established. All found grains are divided into three contrasting types: the refractory triad Os–Ir–Ru, essentially platinum with the participation of Pd, and Cu–Pd. Almost all found PGM grains are localized either in the peripheral parts of grains of altered sulfides (heazlewoodite, pentlandite) or in the silicate matrix in the immediate vicinity of sulfide segregations. Based on the mineral associations and PGE distribution, a probable genesis of segregations has been suggested. Associations of Cu–Pd and Pd–Pt(+Cu) composition most likely formed during the crystallization of sulfides from the extracted partial melts. This is indicated by their close association with clinopyroxenes and the presence of relatively fusible platinoids and copper. The associations of Pt–Ir and Os–Ir–Ru(+Pt) composition are most likely restitic, formed in place of primary mantle sulfides as a result of extraction of more fusible elements and further desulphurization. The isolation of platinoids as their own mineral phases is associated with the influence of superimposed low-temperature processes – subsolidus redistribution during cooling and subsequent serpentinization.

GEOECOLOGICAL STUDIES

227-235 124
Abstract

The growing worldwide practice of biochar application as soil ameliorants, as well as adsorbents for remediation of soil contaminated with oil products and heavy metals, can lead to an increase the risk of environmental pollution by pyrolysis by-products. One of the most dangerous components of biochars is polycyclic aromatic hydrocarbons (PAHs), which are inevitably formed during the production of pyrogenic material. In this work, biochars obtained from various plant materials (millet, corn, willow, linden) under different pyrolysis temperatures were tested for the content of polycyclic aromatic hydrocarbons. The total content of PAHs in the studied samples ranged from 8.49 to 221.21 µg/ kg, which does not exceed the limit concentrations established by the International Biochar Initiative. At the same time, polynuclear hydrocarbons with high carcinogenic and immunotoxic properties are found in the composition of biochars. A natural question arises about the effect of the final pyrolysis temperature on the total content and composition of PAHs in pyrolysis by-products. To study the degradation of polycyclic aromatic hydrocarbons in soil, linden biochar obtained by pyrolysis at 250 °C was used, from which the contaminants were extracted and applied to the soil so that the concentration of the marker was 20 and 40 µg/kg. The determination of the residual amount of polycyclic aromatic hydrocarbons was carried out after 1, 2, 6, and 11 months of incubation. Complete degradation of some 3–5-membered polycyclic aromatic hydrocarbons was found after 1–2 months of incubation. The most persistent pollutants were benzo(a) pyrene, benzo(b)fluoranthene, and pyrene, the concentration of which decreased to 31–71% on after 11 months of incubation. The slower degradation was found in the variant of the experiment with the high concentration level of polycyclic aromatic hydrocarbons. It was concluded that in soils selective accumulation of polynuclear PAHs, that most resistant to biodegradation, can occur.

ALTERNATIVE ENERGY SOURCES

216-226 353
Abstract

Currently, in the energy strategies presented by Japan, the Republic of South Korea, the Russian Federation and the countries of the European Union, hydrogen is considered as a promising energy carrier that should replace fossil fuels (oil, gas, coal) and be used for accumulation, storage and delivery of energy to different regions of the world. The improvement of hydrogen energy technologies plays a special role in the low-carbon development of the world economy. The main advantages of hydrogen are the possibility of obtaining it from various sources and the absence of carbon dioxide emissions when it is used as an energy carrier, which is especially important against the backdrop of the current climate agenda. In the meantime, this energy carrier is artificially created, since there are no deposits of free hydrogen in nature. Therefore, hydrogen should be perceived precisely as a “carrier” of energy, and not as a fuel. The purpose of this study is to substantiate the feasibility of building tidal power plants, the development of hydrogen technologies and industrial complexes in the Russian Federation.

GEORESOURCES AND PHILATELY



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ISSN 1608-5043 (Print)
ISSN 1608-5078 (Online)