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Date submitted2024-03-11
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Date accepted2024-11-07
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Date published2025-03-06
Geochemical characteristics of weathering crusts on the Dzhezhimparma Ridge and the Nemskaya Upland (South Timan)
Numerous local varieties of weathering crusts are known in the South Timan. They differ in their position in the section, type of weathering products, substrates, and occurrence. The aim of the research is to identify patterns in the distribution of rock-forming, rare and rare earth elements and the composition of clay minerals in clay formations of the weathering crusts. The main task is to describe the occurrence and geochemical features that enable determining the genetic type and formation conditions of weathering crusts. The paper presents the results of a study of the distribution of petrogenic, rare earth, rare elements, and clay minerals in weathering crust of different ages, genetic types and occurrence conditions on the Dzhezhimparma Ridge and the Nemskaya Upland in the South Timan. We found that hydromica-kaolinite-type weathering crust is developed after the Late Riphean Dzhezhim Fm. rocks in the basement-cover contact zone on the Dzhezhimparma Upland, and the layer of fine-grained rock at the base of the Devonian section previously considered a weathering crust was formed as a result of mechanical destruction of the Devonian sandstones during movement in the thrust zone. In the Vadyavozh quarry located on the Nemskaya Upland, we studied and described the formations of Mesozoic-Cenozoic areal and linear weathering crusts after the Late Riphean Dzhezhim Fm. rocks. We found that micaceous siltstones in the siltstone-sandstone strata of the Dzhezhim Fm. are associated with the Riphean stage of crust formation and are composed of weathering crust material redeposited in the epicontinental basin.
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Date submitted2024-03-20
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Date accepted2024-11-07
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Date published2025-02-27
Analysis of the stress state of rocks transformation near a horizontal well during acid treatment based on numerical simulation
The article presents an overview of the assessment and modelling of the stress state of rocks in the near-wellbore zone of horizontal wells during acid stimulation of the formation for improving the efficiency of oil and gas field development. A numerical finite element model of near-wellbore zone of the reservoir drilled by a horizontal section was compiled using one of oil fields in the Perm Territory as an example. The distribution of physical and mechanical properties of the terrigenous reservoir near the well was determined considering transformation under the action of mud acid for different time periods of its injection. Multivariate numerical simulation was performed and the distribution of horizontal and vertical stresses in near-wellbore zone was determined with regard for different values of pressure drawdown and changes in stress-strain properties depending on the area of mud acid infiltration. It was found that a change in elastic modulus and Poisson's ratio under the influence of acid led to a decrease in stresses in near-wellbore zone. Analysis of the stress distribution field based on the Coulomb – Mohr criterion showed that the minimum safety factor of rock even after the effect of mud acid was 1.5; thus, under the considered conditions of horizontal well modelling, the reservoir rock remained stable, and no zones of rock destruction appeared.
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Date submitted2023-10-31
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Date accepted2024-11-07
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Date published2025-01-24
Specifics of magnetotelluric studies in Antarctica
One of the priority areas of scientific research in Antarctica is the study of its deep structure. Most of the continent is covered with a thick ice sheet, so the main geoscientific data are acquired using geophysical methods, among which magnetotelluric (MT) ones have the greatest penetration depth and insignificant environmental impact. The possibility of acquiring high-quality MT data in the conditions of the sixth continent has long been questioned. The work is aimed at studying the specifics of magnetotelluric survey in Antarctica. The following tasks were set: to summarize the world experience of studying Antarctica using MT sounding methods; to identify factors that negatively affect the high-quality data acquisition; to determine methods for minimizing the influence of these factors. The article analyses geophysical studies conducted by the magnetotelluric sounding method in the Antarctic region from 1964 to the present. The application of the method is complicated by the following: extremely low temperature affects the drop in the batteries capacity, freezing of the non-polarizing electrodes solution, and changes in the strength properties of materials. Electromagnetic noise occurs during strong winds; proximity to the magnetotelluric field source can violate the plane wave principle on which the method is based. The ice sheet covering most of Antarctica does not allow acquiring optimal values of the contact resistance of the electrode grounding; the extended coastline distorts the acquired data. Studies of the influence of factors complicating the MT sounding method in the coastal and central parts of Antarctica made it possible to formulate recommendations for preparing equipment and adapting the work procedure, modifying the processing flow and a set of measures to ensure safety, the implementation of which will both allow safe performance of geophysical investigations and high-quality data acquisition.
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Date submitted2023-07-04
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Date accepted2023-09-20
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Date published2023-10-27
Structure maintenance experience and the need to control the soils thermal regime in permafrost areas
- Authors:
- Anatolii V. Brushkov
- Andrei G. Alekseev
- Svetlana V. Badina
- Dmitrii S. Drozdov
- Vladimir A. Dubrovin
- Oleg V. Zhdaneev
- Mikhail N. Zheleznyak
- Vladimir P. Melnikov
- Sergei N. Okunev
- Aleksei B. Osokin
- Nikolai A. Ostarkov
- Marat R. Sadurtinov
- Dmitrii O. Sergeev
- Roman Yu. Fedorov
- Konstantin N. Frolov
The risks of reducing the stability of buildings and structures are increasing in conditions of climate change and the active development of the territories under the influence of natural and anthropogenic factors. The main causes include: loss of the bearing capacity of frozen soils, various geocryological processes, errors at the stages of design, construction and operation of facilities. Main actual task when conducting research and industrial operations in the cryolithozone is monitoring and, if necessary, managing thermal processes in the permafrost layers interacting with facilities. In this article the obtained positive experience of various technologies applying at various stages of the life cycle of civil and industrial facilities was analyzed. It helps to eliminate or prevent the structure deformation or destruction under the influence of climate change. The methods of permafrost stabilization used in the oil and gas industry in process of industrial infrastructure development of the fields have been studied – freezing (cooling) of foundation soils during construction on heterogeneous foundations. The solution to the problems of minimizing accidents when locating production wells in the permafrost zone of the Yamal Peninsula is considered using the example of an oil and gas condensate field and restoring of the temperature regime of perennial unfrozen soils in areas of valve units of main gas pipelines. An assessment of methods used to maintain the industrial and residential infrastructure within the northern municipalities that ensure the functioning of the fuel and energy complex of the Russian Federation in the Arctic was made. The systems of thermal stabilization in the foundations of buildings and industrial facilities built and operated on permafrost soils allow to fully use the high strength and low deformability of frozen grounds. It ensures the state's long-term plans of the industrial development in the Arctic.
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Date submitted2023-03-30
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Date accepted2023-09-21
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Date published2023-10-27
Mineral composition and thermobarometry of metamorphic rocks of Western Ny Friesland, Svalbard
The results of the study of mineral composition and microstructure of representative metapelitic and calcic pelitic schist and amphibole-biotite gneiss, occurring in the northern part of the Western Ny Friesland anticlinorium, are reported. Mineral composition was analyzed with a JSM-6510LA scanning electron microscope with a JED-2200 (JEOL) energy dispersive spectrometer. Metamorphic conditions were assessed with various mineral geothermometers (garnet-biotite, Ti-in-biotite, Ti-in-muscovite, Ti-in-amphibole, garnet-amphibole, amphibole-plagioclase, and chlorite) and geothermobarometers (GASP, GBPQ, GRIPS, GBPQ, phengite, etc.). It has been shown that peak temperature and pressure for rocks of the Paleoproterozoic Atomfjella Series forming the western limb of the anticlinorium are consistent with those for the high-pressure part of the upper amphibolite facies (690-720 °С, 9-12 kbar), and the peak temperature and pressure for rocks of the Mossel Series occurring in the eastern limb and rest on the Atomfjella rock sequence, are consistent with the high-pressure part of the lower amphibolite facies (580-600 °С, 9-11 kbar). In addition to the high-temperature parageneses Ms-Bt-Grt-Pl (±Ky, St), Bt-Grt-Pl-Kfs-Cal (±Scp) and Bt-Hbl-Ep-Grt-Pl, the rocks of the both series display the low-temperature assemblage Ms-Chl-Ep-Ab-Prh-Ttn, which was formed upon transition from greenschist to prehnite-pumpellyite facies (260-370 °С).
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Date submitted2022-06-27
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Date accepted2023-06-20
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Date published2023-12-25
Analysis of the problems of high-quality drinking water extraction from underground water intakes on Vysotsky Island in the Vyborg district of the Leningrad region
This article presents the results of drilling, experimental filtration work and laboratory studies aimed at assessing the resources and quality of groundwater in the licensed area of Vysotsky Island located in the Leningrad region, in the Gulf of Finland in accordance with the requirements of regulatory documents. Analysis of the results of hydrochemical studies and their comparison with data on water intakes in adjacent areas gives the right to conclude that it is possible to classify a hydrogeological unit as a different type of resource formation than those located in the surrounding areas. Groundwater in this area is confined to an unexplored deep fractured regional high-pressure zone. According to the received data, the explored water intake can be attributed to a unique groundwater deposit, which has an uncharacteristic composition of groundwater in the north of the Leningrad region, which may be due to the mixing of modern sediments and relict waters of the Baltic glacial lake. The stability of groundwater characteristics is confirmed by long-term monitoring.
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Date submitted2023-03-14
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Date accepted2023-06-20
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Date published2023-07-19
Evaluation of the energy efficiency of functioning and increase in the operating time of hydraulic drives of sucker-rod pump units in difficult operating conditions
The necessity of improving the drives of the sucker-rod hydraulic pump units (SRHP), operated in conditions of marginal and complicated wells, is substantiated. For complicated oil production conditions, it is promising to use the SRHP drive, which makes it possible to select and set rational operating modes for downhole equipment. The results of comparative tests of conventional mechanical and hydraulic actuators SRHP with pneumatic and electrodynamic balancing types are presented. A generalized indicator for evaluating the effectiveness of the advanced SRHP drives functioning, the energy efficiency coefficient, is proposed. It has been experimentally proven that the use of the SRHP drive with pneumatic balancing is characterized by low energy efficiency of the well fluid production process. The use of the tested SRHP hydraulic drive made it possible to successfully eliminate asphalt, resin, and paraffin deposits and minimize the well downtime. The results of the tests of the traditional SRHP mechanical drive and the hydraulic drive with electrodynamic balancing showed a satisfactory energy efficiency of the latter. The advantage of the SRHP drive with electrodynamic balancing is the simplicity of the design of the hydraulic part. The process of energy regeneration during the drive control system operation causes an increase in the reactive power component in the oil field network and the appearance of harmonic interference that adversely affects the consumers operation. Technical solutions aimed at improving the operation energy efficiency and increasing the operating time of SRHP drives in the conditions of marginal and complicated wells are proposed. The methodological bases for assessing the economic efficiency of the introduction of the advanced SRHP drives are given.
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Date submitted2022-09-30
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Date accepted2023-02-13
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Date published2023-04-25
Hydrogeoecological conditions of technogenic groundwater in waste disposal sites
The specific hydrogeoecological conditions of aquifers of some technogenic formations, mainly iron ore skarn-magnetite and titanium-magnetite formations, are considered. The resulting wastes, which are stored in waste disposal sites during development of deposits, due to the impact of a number of factors (natural and technogenic) form technogenic waters. Waste disposal facilities are complex engineering structures (dumps and sludge storages), which in turn create their own hydrogeoecological conditions, which must be investigated in order to prevent and minimize environmental and economic damage caused by these objects to the aquatic environment. The paper presents long-term field and laboratory studies of the aquatic environment under the influence of a waste disposal facility in the Middle Urals – one of the largest tailings, representing a potential environmental and man-made hazard. This tailing dump contains tens of tons of waste – enrichment tailings and creates specific hydrogeoecological conditions on the territory. Based on many years of monitoring studies, an analysis of these conditions was carried out – the quality of groundwater affected by the tailings was assessed. It is shown that groundwater is of technogenic nature, i.e. are man-made waters that have a significant impact on the surface and underground hydrospheres of the territory.
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Date submitted2022-06-09
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Date accepted2022-11-17
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Date published2022-12-29
Drilling of deep and ultra-deep wells for prospecting and exploration of new raw mineral fields
Scientific and technological progress over the last century has led to an enormous increase in the consumption of minerals, including energy resources. Most of the exploited oil and gas fields are already considerably depleted, so it is necessary to search for new hydrocarbon resources, particularly at great depths. Deep drilling plays a special role in solving this problem. The article considers the world and Russian experience of ultra-deep wells drilling. The methods and technologies used in the construction of wells, as well as complications and accidents occurring during their drilling were analyzed. The analysis revealed that the existing limitations for drilling parameters of deep and ultra-deep wells are caused by the technical characteristics of surface and bottomhole drilling equipment, which do not meet the extreme drilling conditions. The directions for development of deep and ultra-deep well drilling machinery and technologies are suggested. The notion of extreme rock and geological drilling conditions is introduced, which describes drilling in conditions of hydrostatic pressure of flushing fluid column and high bottomhole temperature both at stable and unstable wellbore conditions, coming close to the upper limit of operating technical characteristics of bottomhole assembly, the drill string and flushing fluid.
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Date submitted2021-05-27
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Date accepted2022-09-06
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Date published2022-11-10
Application of resonance functions in estimating the parameters of interwell zones
It is shown that the use of force resonance leads to the effect of “shaking” the formation, followed by breaking up the film oil and involving it in the further filtration process. For the first time in oilfield geophysics, the concept of passive noise-metering method is justified for monitoring oil and gas deposit development by measuring the quality factor of the contours in the point areas of formation development channels in interwell zones. It is established that determining the depth of modulation for the reactive substitution parameter of the linear FDC chain is crucial not only for determining the parametric excitation in FDC attenuation systems, but also without attenuation in the metrological support for the analysis of petrophysical properties of rock samples from the wells. It is shown that based on the method of complex amplitudes (for formation pressure current, differential flow rates, impedance), different families of resonance curves can be plotted: displacement amplitudes (for differential flow rates on the piezocapacity of the studied formation section), velocities (amplitudes of formation pressure current) and accelerations (amplitudes of differential flow rates on the linear piezoinductivity of the FDC section). The use of predicted permeability and porosity properties of the reservoir with its continuous regulation leads to increased accuracy of isolation in each subsequent sub-cycle of new segment formation in the FDC trajectories, which contributes to a more complete development of productive hydrocarbon deposits and increases the reliability of prediction for development indicators.
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Date submitted2022-04-29
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Date accepted2022-07-21
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Date published2022-11-10
Deep structure, tectonics and geodynamics of the Sea of Okhotsk region and structures of its folded frame
The use of the zonal-block model of the earth's crust for the construction of regional tectonic schemes and sections of the earth's crust based on a complex of geological and geophysical data makes it possible to consider the resulting maps and sections as tectonic models. The main elements of such models are blocks with an ancient continental base and interblock zones formed by complexes of island arcs, an accretionary prism, or oceanic crust. The developed geotectonic model of the Sea of Okhotsk region reflects the features of the deep structure, tectonics, and geodynamics. The Cimmerian Novosibirsk-Chukotka, Verkhoyansk-Kolyma, Kolyma-Omolon, and Amur folded regions and the Alpides of the Koryak-Kamchatka and Sakhalin-Sikhote-Alin folded regions are developed along the northern, western, and southern boundaries of the Sea of Okhotsk megablock with a continental crust type. From the east, the megablock is limited by oceanic basins and island arcs.
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Date submitted2021-06-24
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Date accepted2021-10-18
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Date published2021-12-16
Modeling the acid treatment of a polymictic reservoir
- Authors:
- Mars M. Khasanov
- Andrey А. Maltcev
Acid treatment of wells program is directly related to oil production efficiency. Investigations aimed at improving the efficiency of acid treatment in a terrigenous reservoir have mainly reviewed the changing and adapting the reagents to minimize bridging caused by acid-rock interaction. Under real conditions, application of new and unique acid compositions is a complex process from an organizational point of view and is therefore not widely used as compared with conventional compositions based on a mixture of hydrochloric and hydrofluoric acids. The paper is based on an approach to improve acid treatment efficiency through optimal design based on near-bottomhole zone treatment simulation. The aspects for practical application of the developed acid treatment simulator for terrigenous reservoirs based on a numerical model of hydrodynamic, physical and chemical processes in a porous medium on an unstructured PEBI-grid are described. The basic uncertainties of the model are identified and analyzed. Influence of empirical parameters within the system of equations on the calculation results and modeling of the mineralogical composition of rocks are considered. Algorithm for static modelling of near-bottomhole zone for acid treatment modelling is described, as well as an approach to optimizing the design of near-bottomhole zone treatment based on adapting the results of rock tests in the model. Using experimental data, the necessity of accounting for influence of secondary and tertiary reactions on the results of modeling physical and chemical processes during acid treatment of terrigenous reservoirs was proved. The distinctive features of West Siberian objects (polymictic reservoirs) with respect to the efficiency of near-bottomhole zone treatment with clay acid have been investigated. Series of calculations to determine the optimum volume of acid injection has been carried out. Experience of previously conducted measures under the considered conditions has been analyzed and recommendations to improve the efficiency of acid treatment have been given.
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Date submitted2021-04-11
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Date accepted2021-10-18
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Date published2021-12-16
Comprehensive assessment and analysis of the oil and gas potential of Meso-Cenozoic sediments in the North Caucasus
- Authors:
- Igor I. Bosikov
- Andrey V. Мaier
At the present stage, the development of the oil and gas industry in the Russian Federation is impossible without replenishing the raw material base, so the urgent task is to conduct investigations, prospecting and evaluation of oil and gas bearing capacity prospects in undiscovered areas. The purpose of the investigations is to analyze facies and thicknesses, choose the methodology of prospecting and exploration in reservoirs, make a comprehensive assessment of oil and gas bearing capacity prospects based on experimental investigations and construct a map of oil and gas bearing capacity prospects of the studied sediment structure. The methodology of the conducted investigations was to identify and trace zones of increased fracturing by qualitative interpretation of time seismic sections. Methods for qualitative interpretation of time seismic sections, the model of physical, chemical and geochemical criteria developed by I.A.Burlakov, gas and geochemical surveying and correlation analysis were used in the investigations. A number of prospecting criteria, established based on the analysis of reference seismic materials on well-studied areas in comparison with the results of well tests, were also used. Structural plan for forecast prospects of oil and gas bearing capacity in the studied area was made; zonal and local objects with prospects for oil and gas were identified. Graphical plotting of Eh and pH concentrations distribution and various gas and geochemical indicators allowed identifying zones of possible oil and gas accumulations and starting their detailed survey. Processing of gas and geochemical materials by means of software allowed efficient assessment of prospects for oil and gas bearing capacity of the investigated objects.
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Date submitted2021-03-31
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Date accepted2021-09-29
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Date published2021-10-21
Methodology of modeling nonlinear geomechanical processes in blocky and layered rock masses on models made of equivalent materials
- Authors:
- Boris Yu. Zuev
The research purpose is to develop a methodology that increases the reliability of reproduction and research on models made of equivalent materials of complex nonlinear processes of deformation and destruction of structured rock masses under the influence of underground mining operations to provide a more accurate prediction of the occurrence of dangerous phenomena and assessment of their consequences. New approaches to similarity criterion based on the fundamental laws of thermodynamics; new types of equivalent materials that meet these criteria; systems for the formation of various initial and boundary conditions regulated by specially developed computer programs; new technical means for more reliable determination of stresses in models; new methods for solving inverse geomechanical problems in the absence of the necessary initial field data have been developed. Using the developed methodology, a number of complex nonlinear problems have been solved related to estimates of the oscillatory nature of changes in the bearing pressure during dynamic roof collapse processes; ranges of changes in the frequency of processes during deformation and destruction of rock mass elements, ranges of changes in their accelerations; parameters of shifts with a violation of the continuity of the rock mass under the influence of mining: secant cracks, delaminations, gaping voids, accounting for which is necessary to assess the danger of the formation of continuous water supply canals in the water-protection layer.
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Date submitted2020-10-26
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Date accepted2021-07-28
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Date published2021-10-21
Investigation of the influence of the geodynamic position of coal-bearing dumps on their endogenous fire hazard
The paper investigates the hypothesis according to which one of the factors influencing the spontaneous combustion of coal-bearing dumps is its geodynamic position, i.e. its location in the geodynamically dangerous zone (GDZ) at the boundary of the Earth crust blocks. This hypothesis is put forward on the basis of scientific ideas about the block structure of the Earth crust and the available statistical data on the location of burning dumps and is studied using computer modeling. A dump located in the area of Eastern Donbass was chosen as the object of research. The simulation results show that the penetration of air into the dump body from the mine through the GDZ, which crosses the mining zone, is possible at an excess pressure of 1000 Pa created by the main ventilation fans. The fire source appearance in the dump body causes an increase in the temperature of the dump mass and becomes a kind of trigger that "turns on" the aerodynamic connection between the dump and the environment, carried out through the GDZ. It is concluded that the establishment of an aerodynamic connection between the mine workings and the dump through the GDZ can be an important factor contributing to the endogenous fire hazard of coal-bearing dumps. The simulation results can be used in the development of projects for monitoring coal-bearing dumps and measures to combat their spontaneous combustion.
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Date submitted2020-09-09
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Date accepted2021-03-29
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Date published2021-09-20
Developing features of the near-bottomhole zones in productive formations at fields with high gas saturation of formation oil
The article studies the formation features of the bottomhole zones in productive formations during operation of production wells in the north of the Perm Territory. Their distinctive feature is the high gas saturation of formation oil. The most widely used parameter in Russian and world practice – the skin factor was used as a criterion characterizing the state of the bottomhole zone. Analysis of scientific publications has shown that one of the main problems of applying the skin factor to assess the state of bottomhole zones is the ambiguity of interpretations of its physical meaning and the impossibility of identifying the prevailing factors that form its value. The paper proposes an approach to identifying such factors in the conditions of the fields under consideration, based on multivariate correlation-regression analysis. Choice of this tool is due to the complexity of the processes occurring in the “formation – bottomhole zone – well” system. When describing complex multifactorial processes, the chosen method demonstrates a high degree of reliability. For a large number of wells in the region, significant material was collected and summarized, including the results of determining the skin factor (1102 values) during hydrodynamic investigations, as well as data on the values of various geological and technological indicators, which can probably be statistically related to the value of the skin factor. A series of multidimensional mathematical models has been built; the skin factor was used as a predicted parameter, and data on the values of geological and technological indicators were used as independent indicators. Analysis of the constructed models is a key stage of this study. Set of parameters included in the multidimensional models, sequence of their inclusion and contribution to the total value of the achieved determination coefficient as the main indicator for the performance of the constructed models were studied. It has been established that the main factor influencing the state of the bottomhole zone is oil degassing. Significant differences in the formation features of the skin factor in the terrigenous and carbonate sediments at the fields under consideration have been determined.
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Date submitted2021-01-20
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Date accepted2021-03-29
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Date published2021-09-20
Analysis of the causes of engineering structures deformations at gas industry facilities in the permafrost zone
Construction of oil and gas infrastructure facilities on permafrost soils is the most important task of increasing the raw material base of the entire fuel and energy industry in Russia. Permafrost soil is a complex, multicomponent system, state of which depends on many factors. Buildings and structures built under such conditions, on the one hand, have a complex thermal effect on permafrost soils, and on the other hand, they perceive the consequences of changes in the characteristics of such soils. This situation leads to the fact that buildings and structures on permafrost soil during their life cycle are subject to complex and poorly predictable deformations. Article presents the results of a study for various degradation processes of permafrost soils that can be implemented at construction sites of industrial facilities. Analysis of the deformations causes for engineering structures at the gas industry in the permafrost zone is carried out. Series of reasons causing such deformations have been investigated. Comprehensive criterion for assessing changes in permafrost-geological conditions of industrial sites is proposed. It is suggested to apply the method of calculating the individual characteristics for the temperature regime of the territory to monitor and assess the conditions of heat exchange and predict changes in the geocryological conditions of permafrost soil.
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Date submitted2020-09-10
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Date accepted2020-11-25
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Date published2021-06-24
Formation conditions of noble metal mineralization in sulfide cobalt-copper-nickel ores of Kamchatka (on the example of Annabergitovaya Schel ore occurrence)
The authors present research results, the purpose of which is to study the specifics of noble metal mineralization and its genesis in sulfide cobalt-copper-nickel ores of the Kamchatka nickel-bearing province. The paper is dedicated to one of its many ore occurrences called Annabergitovaya Schel (Annabergite Gap). The material composition of platinoid, silver, gold, bismuth and tellurium minerals, as well as sulfarsenides in the ores of this occurrence was investigated. Based on the data of mineral formation sequence and the use of geosensors, conclusions were drawn regarding the genesis of noble metal mineralization. Formation of platinoid minerals, silver and gold at the Annabergitovaya Schel ore occurrence is mainly associated with the epigenetic effect of post-ore granitoids on ore-bearing intrusion rocks of the Dukuk complex of the cortlandite-norite formation and on syngenetic ores. An early association of noble metal minerals is represented by sperrylite, irarsite, and rare unnamed phases of Pt + Ir + Te. Irarsite and Pt + Ir + Te phases were formed at the contact-metasomatic stage. Sperrylite can be assumed to be of magmatic origin. Silver sulfides and tellurides, silver and palladium bismuth tellurides, and native gold were formed at the late, hydrothermal-metasomatic, stage. The occurrence conditions of mineral parageneses, associated with noble metal mineralization, correspond to the formation of shallow-depth metasomatic rocks (≤5 km). Sub-developed quartz-feldspar metasomatites, associated with the formation of early platinoid arsenides and sulfarsenides, are in equilibrium with circumneutral solutions (pH of 4.5-6.5) at temperatures of 350-600 °C. Late hydrothermal association with Pd, Ag and Au minerals is close to propylites and was formed at pH values of 4.5-6.5 and temperature of 150-350 °C.
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Date submitted2021-01-28
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Date accepted2021-04-21
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Date published2021-06-24
Unusual metasomatites (phyolithites) in the Kolvitskiy gabbro-anorthosite rock mass: composition and structural position
Complex mineralogical, geochemical, and geological-structural characteristics of a rare collection stone of violet color, phyolithite, in the southwestern part of the Kola Peninsula. This is a metasomatic rock formed under the conditions of brittle deformations on gabbro-anorthosites of the Paleoproterozoic Kolvitskiy rock mass. As a result of potassium metasomatosis, the plagioclase of the initial rocks was replaced by a fine-grained mica aggregate of muscovite-phengite composition with inclusions of Va-aluminoseladonite (up to 20-30 microns). Ba-aluminoseladonite contains 6.6-10.5 % by weight of BaO. Manganese is the only chromophore that accumulates in the rock during metasomatosis. It is manganese that provides the purple-violet color of pseudomorphs of mica according to anorthite. The phyolithites is depleted by REE and has a positive Eu-anomaly. The phyolithites are confined to the areas of fracturing of the north-eastern strike, located in the zone of dynamic influence of the north-western closure of the Onega-Kandalaksha rift of the Riphean age. Other formations (injection conglomerates and lamproites) are also associated with the formation of this structure, which owe their origin to an intense fluid flow.
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Date submitted2020-08-20
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Date accepted2021-04-01
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Date published2021-06-24
Features of the mineral and chemical composition of the Northwest manganese ore occurrence in the Highveld region, South Africa
- Authors:
- Aleksandr N. Evdokimov
- Benedict L. Pharoe
The Northwest manganese ore mineralisation is located at a relative distance from traditionally known manganese mining areas in a new manganese-bearing region (Highveld) in the Northwest Province, Republic of South Africa. The ore occurrence was studied on farms: Buchansvale 61 IQ, Weltevreden 517 JQ, Rhenosterhoek 343 JP and Kafferskraal 306 JP. The data obtained from studying the geology of the area pointed out to interests regarding the development criterias for search of similar ore mineralisations in the northwest region of South Africa. The ore occurs predominantly in the form of powdered manganese wad, manganese nodules and crusts, confined to the karstic structures of the upper section of the dolomites. X-ray powder diffraction (XRD), Scanning electron microscopy with energy dispersive link (SEM-EDS) and X-ray fluorescence were utilized to unveil the mineral and chemical composition of the ore samples. The present study therefore presents the results on both chemical and mineral composition of manganese ores, and their depth and longitudinal distribution. Karstic areas causing an increased local thickness of the ore body were identified. The geochemical and microspcopic study of the ores indicates their supergene nature. The main ore minerals includes cryptomelane, lithiophorite, purolusite, hollandite and romanechite associated with impurity components of Ba, Ce, Co, La, Cr, Zn and V.
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Date submitted2020-11-11
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Date accepted2021-03-02
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Date published2021-04-26
Oil and gas content of the understudied part in the northwest of the Timan-Pechora oil and gas province according to the results of basin modeling
Comprehensive interpretation of the results for regional seismic operations and reinterpretation of archived seismic data, their correlation with the drilling data of more than 30 deep wells, including Severo-Novoborsk parametric well, made it possible to clarify the structural maps and thickness maps of all seismic facies structures developed in the territory and water area in the junction of the north of Izhma-Pechora depression and Malozemelsko-Kolguevsk monocline of Timan-Pechora oil and gas province. Data obtained were used at basin modeling in TemisFlow software in order to reconstruct the conditions of submersion and transformation of organic substance in potential oil and gas bearing formations. Modeling made it possible to get an idea of the time and conditions for the formation of large zones of possible hydrocarbons accumulation, to establish space-time connections with possible sources of generation, to identify the directions of migration and on the basis of comparison with periods of intense generation, both from directly located within the operation area and outside them (taking into account possible migration), to identify zones of paleoaccumulation of oil and gas. Work performed made it possible to outline promising oil and gas accumulation zones and identify target objects for further exploration within the site with an ambiguous forecast and lack of industrial oil and gas potential.
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Date submitted2021-02-05
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Date accepted2021-03-30
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Date published2021-04-26
Assessment of negative infrastructural externalities when determining the land value
- Authors:
- Elena N. Bykova
The work forms and substantiates the concept of land value, based on a new institutional theory. The infrastructural component of the cost of land in the presented concept determines, on the one hand, the efficiency of the use of natural resources, properties, demand for land on the market, on the other hand, the costs, which are determined not only by capital investments in construction of engineering infrastructure, but also by losses associated with restrictions on activities within zones with special conditions for territory use, creation of unfavorable conditions for economic activity, small contours, irregularities and others on a specific land plot, which are external negative infrastructural externalities that create losses of rights holders of land plots that are not compensated by the market, falling within the boundaries of these zones. Methods for assessing the impact of such negative infrastructural externalities on the cost of land encumbered by zones in different conditions of land market activity have been developed and tested, based on an expert-analytical approach (depressed market); the ratio of market values of land plots encumbered and unencumbered by a specific zone, and qualimetric modeling (inactive market); modeling by introducing into the model the factor of presence of zones with special conditions for territory use, based on the grouping of zones according to similar regulations for use, or by introducing the parameters of this factor (active market). Methods for taking into account spatial deficiencies and compensating for restrictions and prohibitions on activities on the territory of land plots with an individual market assessment are proposed.
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Date submitted2019-12-20
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Date accepted2020-09-01
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Date published2020-10-08
Features of the underground storages construction in depleted oil and gas condensate fields
The paper considers the features of the underground storages (US) construction in depleted oil and gas condensate fields (DOGCFs). The requirements for the structure of the formation, corresponding to the parameters of the object for possible US creation are presented. The influence of geological, hydrogeological, mining and technical rock formation conditions on the reliability and tightness of underground storages, including underground gas storages, has been evaluated. The necessary conditions for the US design are analyzed at the example of the Ach-Su oil and gas condensate field, in the presence of a well-explored trap with acceptable parameters for the construction of an underground storage. An important aspect is the geological conditions that meet the criteria for selecting the object: the required structure, the absence of fracturing faults, high reservoir properties of the formation, a sufficient volume of the deposit for the storage. Geological conditions lay the basis for determining the individual characteristics of the US construction technology at each DOGCF. The refined results for the current gas-saturated pore volume and the rate of pressure drop in the formation are presented, which makes it possible to select improved technological indicators in the course of operation of the created US. In order to select the optimal option for the design and construction of the US, the results of economic and geological scenarios analysis were studied concurrently with the capabilities of the technological operation of the object and transport system, which can ensure the maximum daily production of the storage.
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Date submitted2020-02-19
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Date accepted2020-04-17
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Date published2020-10-08
Decrease in coal losses during mining of contiguous seams in the near-bottom part at Vorkuta deposit
- Authors:
- Oleg I. Kazanin
- Valeriy V. Yaroshenko
The problem of formation of extended zones with high rock pressure (HRP) from safety pillars at the boundaries of extraction pillars formed due to the mine layout of complex geometry is considered at the example of JSC Vorkutaugol mines. A detailed analysis of the remaining reserves of the near-bottom part of the deposit was carried out to estimate losses and the impact of HRP zones from the Chetvertyi protective seam to mining operations on the Troinoi upper seam along with the possibilities for the reduction of sizes of HRP zones at the account of expanding the underworked space. Due to research on the near-bottom part of the Vorkuta deposit, within the framework of the accepted layout, a zone at the Komsomolskaya mine and two zones at the Zapolyarnaya-2 mine were singled out, at which losses at the boundaries of the extraction pillars amount up to 13-22 % of the total resources of the mine field. The high volume of losses in these pillars indicates the relevance of research on the priority extraction impact of protective seams on the efficiency and safety of mining operations in the working area of underworked and HRP zones. Based on the analysis of foreign and Russian experience in the pillar cleaning-up at the boundaries of working areas and the methodical guidelines and instructions, a technological scheme was developed that allows increasing the coal mining recovery factor in the near-bottom part of the Vorkuta deposit from 0.75 to 0.9 without fundamental changing of the ventilation and transport networks and also without purchasing any additional mining equipment. The conducted economic calculations confirmed the effectiveness of implementing the new technological scheme for cleaning-up reserves at the boundaries of extraction districts. The economic effect is from 0.079 to1.381 billion rubles of additional profit from coaxial extraction pillars, depending on the mining and geological conditions and the size of the pillars.
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Date submitted2020-05-07
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Date accepted2020-05-24
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Date published2020-06-30
Study of the technogenesis of the Degtyarsky mine by audio-magnetotelluric express sounding
- Authors:
- Vadim A. Davydov
The audio-magnetotelluric express sounding was performed at four sections crossing the mine field of the currently not functioning Degtyarsky mine. Field measurements were carried out by a universal broadband receiver “OMAR-2m” with active electromagnetic field sensors developed at the Institute of Geophysics UB RAS. Based on the obtained data, deep sections of the electrophysical parameters of the medium – apparent resistivity and effective longitudinal conductivity – are drawn. The nature of the geoelectric structure of the section allows mapping of the major lithochemical contamination plume and identifying the tectonic disturbance zones that drain aggressive mine waters. The mine waters of the Degtyarsky mine are a source of dangerous technogenic pollution. Despite the neutralization of surface runoff, underground routes of acidic water migration occur along tectonic cracks, primarily in the zone of the regional Serovsko-Mauksky fault. Tectonic zones in the mine area contain contaminated fissure-vein water, which is transited at a depth of 70 to over 200 m. Discharging ascending springs of such waters can be located at a great distance from controlled hydrological objects and pollute sources of drinking and household water supply. Urban development in the western and eastern parts of Degtyarsk does not fall within the distribution zone of polluted water. The southern part of the city is located beyond the watershed of the mine water flow area, but a danger of local contamination by tectonic disturbance zones remains possible. The worst environmental situation is observed in the northern outskirts of Degtyarsk, which falls into the area of heavy pollution of underground and surface waters. Besides, acidic fumes from the flooded Kolchedanny quarry can affect the health of city residents when emitted to the atmosphere.