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Date submitted2020-05-17
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Date accepted2020-10-05
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Date published2020-11-24
Geological structure of the northern part of the Kara Shelf near the Severnaya Zemlya archipelago according to recent studies
Until recently, the North of the Kara Shelf was completely unexplored by seismic methods. Seismic and seismo-acoustic data that have appeared in recent years have made it possible to decipher features of the regional geological structure. This study solves the urgent problem of determining the prospects for the oil and gas potential of the North Kara sedimentary basin. The relevance of the research is associated with determining the prospects of the oil and gas potential of the North Kara sedimentary basin. The aim of the study is to clarify the age of the reflecting horizons using data on the geology of the island, as well as to determine the tectonic position of the sedimentary cover and basement structures in the north of the Kara shelf. The sedimentary cover is divided into three structural levels: Cambrian-Devonian, Middle Carboniferous-Cretaceous, Miocene-Quarter. The Cambrian-Devonian complex fills the deep troughs of the North Kara shelf. The most noticeable discontinuity is the base of Carboniferous-Permian rocks, lying on the eroded surface of folded Silurian-Devonian seismic complexes. The blanket-like plate part of the cover is composed of thin Carbon-Quarter complexes. The authors came to the conclusion that the fold structures of the Taimyr-Severozemelskiy fold belt gradually degenerate towards the Kara sedimentary basin and towards the continental slope of the Eurasian basin of the Arctic Ocean. A chain of narrow uplifts within the seabed relief, which correspond to narrow anticlines is traced to the West of the Severnaya Zemlya islands. Paleozoic rocks have subhorizontal bedding further to the West, within the Kara shelf. Mesozoic folding in the North of the Kara Sea is expressed exclusively in a weak activation of movements along faults. At the neotectonic stage, the shelf near Severnaya Zemlya was raised and the Mesozoic complexes were eroded. The modern seismic activity of the North Zemlya shelf is associated with the ongoing formation of the continental margin.
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Date submitted2020-05-14
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Date accepted2020-10-05
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Date published2020-11-24
Fahlbands of the Keret archipelago, White Sea: the composition of rocks and minerals, ore mineralization
This paper presents a complex mineralogical and geochemical characteristic (based on SEM-EDS, ICP-MS analysis) of the fahlband rocks of the Kiv-Guba-Kartesh occurrence within the White Sea mobile belt (WSMB ). The term “fahlband” first appeared in the silver mines of Kongsberg in the 17th century. Now fahlbands are interlayers or lenses with sulfide impregnation, located in the host, usually metamorphic rock. The level of sulfide content in the rock exceed the typical accessory values, but at the same time be insufficient for massive ores . Fahlbands are weathered in a different way than the host rocks, so they are easily distinguished in outcrops due to their rusty-brown color. The studied rocks are amphibolites, differing from each other in garnet content and silicification degree. Ore mineralization is represented mainly by pyrrhotite and pyrite, and pyrrhotite grains are often replaced along the periphery by iron oxides and hydroxides, followed by pyrite overgrowth. At the same time, the rock contains practically unaltered pyrrhotite grains of irregular shape with fine exsolution structures composed of pentlandite, and individual pyrite grains with an increased Ni content (up to 5.4 wt.%). A relatively common mineral is chalcopyrite, which forms small grains, often trapped by pyrrhotite. We have also found single submicron sobolevskite and hedleyite grains. The REE composition of the fahlband rocks suggests that they are related to Archean metabasalts of the Seryakskaya and Loukhsko-Pisemskaya structures of the WSMB, rather than with metagabbroids and metaultrabasites common in the study area.
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Date submitted2020-06-19
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Date accepted2020-10-06
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Date published2020-11-24
Practice of using the magnetic treatment devices to intensify the processes of primary oil treating
During the primary treatment of oil, gas and water, complications arise associated with the presence of hard water-oil emulsions, which cause an increase in fluid pressure in the gathering systems, pipeline damage, as well as difficulties in gas separation and preliminary water discharge at the preliminary discharge unit (PRU). Additional problems arise during transportation of highly paraffinic oils associated with the crystallization of paraffin in the flow path of the oilfield equipment and on the inner surface of pipes, leading to a drop in the productivity of pipelines. Article discusses the technology of magnetic-reagent treatment of water-oil media, which allows intensifying the processes of primary oil treatment at the facilities of its production. Bench and pilot tests have shown the ability of the magnetic field to accelerate oil demulsification processes, increasing the percentage of separated water during subsequent settling, and to reduce asphalt-resin-paraffin deposits (ARPD) on the inner surface of oil and gas field equipment. Mechanism of the magnetic field effect on water-oil media is described. Effect of treatment on the integrity of the armour shells of oil-water emulsions was studied. Various modes of magnetic treatment have been investigated with evaluation of its effectiveness. It is shown that the best effect is achieved with the combined use of reagents and a magnetic field. Synergistic effect is observed, which consists in increasing their effectiveness. This made it possible to conclude that this method can be applied to reduce the consumption of reagents used in oil production while maintaining the treatment efficiency.
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Date submitted2020-05-29
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Date accepted2020-09-16
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Date published2020-11-24
Numerical modeling of a double-walled spherical reservoir
Extensive and important class of multilayer shell structures is three-layer structures. In a three-layer structure, a rigid filler plays an important role, due to which the bearing layers are spaced that gives the layer stack high rigidity and durability with a relatively low weight. By combining the thicknesses of the bearing layers and the filler, the desired properties of a three-layer shell structure can be achieved. Compared with traditional single-walled, three-layer construction has increased rigidity and durability, which allows reducing the thickness and weight of the shells. In order to reduce the metal content of the spherical reservoir for storing liquefied gases, this work considers the design of a double-walled reservoir, in which the inter-wall space is filled with reinforced polyurethane. Numerical modeling made it possible to determine the parameters of the stress-strain state of the structure with an error of no more than 5 %. It has been established on the example of a reservoir with a volume of 4000 m 3 that the spatial structure of the spherical reservoir wall can reduce the metal content up to 19 %. Field of application for the research results is the assessment of the stress-strain state of spherical reservoirs at their designing. Method for building the structure of a double-walled spherical reservoir in the SCAD software has been developed, which allows calculating the stress-strain state (SSS) by the finite element method. Numerical model of a double-walled spherical reservoir has been developed. It was found that to obtain calculation results with an error of P ≤ 5 % the size of the final element should not exceed 300×300×δ mm. Design of a double-walled spherical reservoir was investigated. Design parameters have been established to ensure the operational reliability of the structure with a decrease in metal content in comparison with a single-wall reservoir by 19 %.
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Date submitted2020-05-05
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Date accepted2020-10-05
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Date published2020-11-24
Assessment of the Influence of Water Saturation and Capillary Pressure Gradients on Size Formation of Two-Phase Filtration Zone in Compressed Low-Permeable Reservoir
The paper examines the influence of capillary pressure and water saturation ratio gradients on the size of the two-phase filtration zone during flooding of a low-permeable reservoir. Variations of water saturation ratio s in the zone of two-phase filtration are associated with the pressure variation of water injected into the reservoir; moreover the law of variation of water saturation ratio s ( r , t ) must correspond to the variation of injection pressure, i.e. it must be described by the same functions, as the functions of water pressure variation, but be subject to its own boundary conditions. The paper considers five options of s ( r , t ) dependency on time and coordinates. In order to estimate the influence of formation and fluid compressibility, the authors examine Rapoport – Lis model for incompressible media with a violated lower limit for Darcy’s law application and a time-dependent radius of oil displacement by water. When the lower limit for Darcy’s law application is violated, the radius of the displacement front depends on the value of capillary pressure gradient and the assignment of s function. It is shown that displacement front radii contain coefficients that carry information about physical properties of the reservoir and the displacement fluid. A comparison of two-phase filtration radii for incompressible and compressible reservoirs is performed. The influence of capillary pressure gradient and functional dependencies of water saturation ratio on oil displacement in low-permeable reservoirs is assessed. It is identified that capillary pressure gradient has practically no effect on the size of the two-phase filtration zone and the share of water in the arbitrary point of the formation, whereas the variation of water saturation ratio and reservoir compressibility exert a significant influence thereupon.
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Date submitted2020-05-21
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Date accepted2020-10-05
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Date published2020-11-24
Method of calculating pneumatic compensators for plunger pumps with submersible drive
- Authors:
- Eduard O. Timashev
One of the most promising ways to improve the efficiency of mechanized oil production is a plunger pump with a submersible drive, which allows obtaining harmonic reciprocating movement of the plunger. In the pumping process of well products by plunger pumps, oscillations in the velocity and pressure of the liquid in the lifting pipes occur, which lead to an increase in cyclic variable loads on the plunger, a decrease in the drive life period and the efficiency of the pumping unit. To eliminate the pulsation characteristics of the plunger pump and increase the reliability indicators of the pumping unit (in particular, the overhaul period), pneumatic compensators can be used. A method for calculating the optimal technological parameters of a system of deep pneumatic compensators for plunger pumping units with a submersible drive, based on mathematical modeling of hydrodynamic processes in pipes, has been developed. Calculations of the forming flow velocity and pressure in the lifting pipes of submersible plunger units equipped with pneumatic compensators (PC) have been carried out. Influence of the PC technological parameters on the efficiency of smoothing the oscillations of velocity and pressure in the pipes has been analyzed. Non-linear influence of the charging pressure and PC total volume on the efficiency of their work has been established. Optimal pressure of PC charging, corresponding to the minimum pressure in the tubing during the pumping cycle for the considered section of the tubing, is substantiated. Two ultimate options of PC system placement along the lifting pipes are considered. In the first option, PC are placed sequentially directly at the outlet of the plunger pump, in the second - evenly along the lift. It is shown that the first option provides the minimum amplitude of pressure oscillations at the lower end of the tubing and, accordingly, variable loads on the pump plunger. Nature of the pressure and flow velocity oscillations in the tubing at the wellhead for both options of PC placement has similar values .
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Date submitted2020-06-12
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Date accepted2020-10-28
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Date published2020-11-24
Spatial non-linearity of methane release dynamics in underground boreholes for sustainable mining
- Authors:
- Ada K. Dzhioeva
- Vladimir S. Brigida
The paper is devoted to the problem of increasing energy efficiency of coalmine methane utilization to provide sustainable development of geotechnologies in the context of transition to a clean resource-saving energy production. Its relevance results from the fact that the anthropogenic effect of coalmine methane emissions on the global climate change processes is 21 times higher than the impact of carbon dioxide. Suites of gassy coal seams and surrounding rocks should be classified as technogenic coal-gas deposits, while gas extracted from them should be treated as an alternative energy source. Existing practices and methods of controlling coalmine methane need to be improved, as the current “mine – longwall” concept does not fully take into account spatial and temporal specifics of production face advancement. Therefore, related issues are relevant for many areas of expertise, and especially so for green coal mining. The goal of this paper is to identify patterns that describe non-linear nature of methane release dynamics in the underground boreholes to provide sustainable development of geotechnologies due to quality improvement of the withdrawn methane-air mixture. For the first time in spatial-temporal studies (in the plane of CH 4 - S ) of methane concentration dynamics, according to the designed approach, the parameter of distance from the longwall ( L ) is introduced, which allows to create function space for the analyzed process (CH 4 of S-L ). Results of coalmine measurements are interpreted using the method of local polynomial regression (LOESS). The study is based on using non-linear variations of methane concentration in the underground boreholes and specific features of their implementation to perform vacuum pumping in the most productive areas of the undermined rock mass in order to maintain safe aerogas conditions of the extraction block during intensive mining of deep-lying gassy seams. Identification of patterns in the influence of situational geomechanical conditions of coal mining on the initiation of metastable gas-coal solution transformation and genesis of wave processes in the coal-rock mass allows to improve reliability of predicting methane release dynamics, as well as workflow manageability of mining operations. Presented results demonstrate that development of high-methane Donbass seams is associated with insufficient reliability of gas drainage system operation at distances over 40 m behind the longwall face. Obtained results confirm a working hypothesis about the presence of spatial migration of methane concentration waves in the underground gas drainage boreholes. It is necessary to continue research in the area of estimating deviation angles of “advance fracturing” zone boundaries from the face line direction. Practical significance of research results lies in the possibility to use them in the development of scientific foundation for 3D gas drainage of a man-made coal-methane reservoir, taking into account spatial and temporal advancement of the production face.
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Date submitted2020-05-12
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Date accepted2020-09-22
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Date published2020-11-24
Design features of coal mines ventilation using a room-and-pillar development system
- Authors:
- Sergey S. Kobylkin
- Alexander R. Kharisov
The safety of mining operations in coal mines for aerological factors depends on the quality of accepted and implemented ventilation design solutions. The current “Design Manual of coal mine ventilation” do not take into account the features of room-and-pillar development systems used in Russia. This increases the risk of explosions, fires, and gassing. The detailed study of foreign experience in designing ventilation for the considered development systems e of coal deposits allowed to formulate recommendations on the ventilation scheme organization for coal mines using a room-and-pillar development system and the procedure for ventilation during multi-entry gateroad development. Observations have shown that the use of the existing Russian procedure for airing mining sites with a room-and-pillar development system complicates the emergency rescue operations conduct. Low speeds and multidirectional air movement, difficult heat outflow, and the abandonment of coal pillars increase the risk of occurrence and late detection of endogenous fire. The results of numerical modeling have shown that the installation (parallel to the drifts) of ventilation structures in inter-chamber pillars will increase the reliability of ventilation by transferring the ventilation scheme from a complex diagonal to a complex parallel. It will also reduce the amount of air required for the mine site and the total aerodynamic drag. The research made it possible to formulate requirements for the design procedure for coal mines ventilation using a room-and-pillar development system, which consist in the order of working out blocks in the panel, and also the additional use of ventilation structures (light brattice clothes or blowing line brattice).
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Date submitted2020-06-09
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Date accepted2020-11-02
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Date published2020-11-24
Method of drilling process control and experimental studies of resistance forces during bits drilling with PDC cutters
A rational, theoretically proved and empirically verified control system is a condition for optimal management of the drilling process in compliance with the criteria for minimizing the cost of time and material resources. A new generation of rock-cutting tools using PDC cutters (polycrystalline diamante cutters), which are extremely ef fective when drilling wells for various purposes in medium-hard rocks, dictates the need to develop methods and criteria for optimal control of the drilling process using this tool. The paper presents an analysis of the force interaction between rock-cutting elements, face rock, and drilling mud sa turated with slam, highlights the influencing factors and provides dependencies for determining the parameters of rock failure. Empirical verification of the theoretical propositions was carried out based on the data analysis from experimental bit drilling of marble with PDC cutters with a diameter of 76.2 mm, processed using the method of full factor experiment to obtain mathematical models of factors and their graphical interpretation. The method of controlling the drilling process based on the optimal ratio of the tool rotation frequency, axial weight and deepening per one turnover is considered, which allows determining the rock failure mode at the well bottom by indirect signs and choose the optimal values of the drilling mode parameters that correspond to the most optimal conditions in terms of achieving the maximum mechanical drilling speed in conjunction with the rational mode of rock-cutting tool operation. A scheme is presented that contains possible variants of the bit run mode and ways to recognize them by the ratio of the deepening per turnover and the rotation frequency of the rock-cutting tool.
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Date submitted2020-05-24
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Date accepted2020-07-23
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Date published2020-11-24
Estimation of ore contour movements after the blast using the BMM system
Measurement of ore movements by blast is one of the key components of the quality control system at any mining enterprise, which allows to obtain the accuracy necessary for determining the location of ore contours. About 15 years ago, a monitoring system was developed in Australia that allows mine personnel to make three-dimensional measurements of ore blocks movement at each blast. Studies have shown that ore blocks movement is extremely variable, and it characterized by a complete absence of a deterministic component. The consequence is that modeling ore contour movements during the blast will be inaccurate, and the best results for the mining enterprise can only be achieved by directly measuring the movement. The technology of measuring ore contours movements considered in the article is based on three-dimensional movement vectors obtained in different parts of the blasted block, characterized by different movements. It is obvious that the accuracy of determining the ore contours position after the blast is proportional to the number of measurements made on the block. Currently, the movement control technology based on the BMM system is actively used by global mining companies, its use reduces losses and dilution of ore. In 2017, the pilot implementation of the BMM system was started at the Olympiadinsky GOK, and the system is being implemented in several Russian mining companies.
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Date submitted2020-06-16
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Date accepted2020-07-13
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Date published2020-11-24
Study of Aluminum Influence on the Adhesion of Stainless Steel in Flame Spraying
This paper is dedicated to a study of aluminum influence on the improvement of surface adhesion strength. The main purpose of this work is to investigate the strength of adhesion to the substrate by mixing flame spray powder with aluminum, which not only possesses high corrosion resistance and conductivity, but also provides additional strength, as it combines and reacts with other components of the powder. Research results of sandblasting dependence on surface roughness parameter Ra are demonstrated. The paper describes authors’ original device for a measuring instrument “Profilometer”, which was also used for measuring roughness parameter in order to obtain comparative results. Authors present results of adhesion measurements given obtained values of surface roughness by mixing nominal chemical composition of PR-30X13 powder, used as a testing material, with aluminum, which reacts with oxides on the surface of steel substrates, imparts strength to the bonding between the coating and the substrate, protects the base metal due to a combination of chemical components of the powder and creates a layer of dense surface coating. These dependencies are analyzed and parameters, exerting the greatest influence on their values, are identified. Taking into account the results obtained through numerical modeling, authors propose a mathematical model of a dependency between adhesion strength and certain values of surface roughness for different chemical compositions of flame spray powder. These studies will help in the development of certain material types for spraying and hardening of steel parts and products in order to improve their durability.