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Date submitted2023-12-07
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Date accepted2024-11-07
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Date published2025-04-07
Determination of the tangential component of cutting resistance during frozen sedimentary rock cutting using blocked, deeply blocked and cell cutting methods
Due to the insufficient accuracy of existing studies of frozen sedimentary rock cutting process for practical calculations, the article solves the problem of determining the tangential component cutting resistance for blocked, deep blocked and cell cutting, which are currently the most commonly used methods in earthmoving equipment. The cutting tool and rock mass force interaction is considered from the point of view of the emerging stresses, which act on the separated chip element. The analytical dependences for determining the tangential component of cutting resistance were obtained. The numerical explanation of the choice of cell cutting in relation to blocked and deeply blocked cutting is given. For all three methods of cutting, under equal geometrical parameters of the cutting tool and the physical and mechanical properties of the frozen rock, the numerical value of the tangential component of cutting resistance is obtained. The comparison of the cutting resistance estimated values has shown that cell cutting requires relatively less energy and is preferred during the process of frozen sedimentary rock excavation. During field and laboratory investigations with the use of a multi-purpose cutting stand, a sufficient convergence of the analytical statements with the physics of frozen sedimentary rock cutting process was established. The results of the research allow a more reasonable approach to the adjustment of existing methods for determining the required tractive force and power for the drive of an excavation machine, and, therefore, to the actual efficiency and profitability of work.
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Date submitted2024-09-06
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Date accepted2025-01-28
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Date published2025-03-27
Results of aeromagnetic survey using unmanned aerial system at the Bunger Hills and Highjump Archipelago, Wilkes Land, East Antarctica
The paper focuses on the technique and results of an aeromagnetic survey conducted using a fixed-wing unmanned aerial system (UAS) in East Antarctica at the Bunger Hills and Highjump Archipelago (Wilkes Land) during the 69th Russian Antarctic Expedition. The above survey was carried out at a 250-meter distance between flight lines (scale 1:25,000) over the area of 600 km 2 to increase the geological knowledge of the area. The magnetic anomaly map obtained after data processing is more detailed than any of known published geological maps of the area. The size of anomalies detected varies from dozens of meters up to large, kilometer-scale structures traced within the entire area under survey. The data analysis shows that the surveyed region is characterized by morphological heterogeneity and amplitude variability of anomalous magnetic field. Along with relatively calm zones one can observe strong gradient ones. Even the fluent analysis of aeromagnetic survey results proves their high information content. The UAS-based survey results demonstrate that the technique implemented is an important tool of applied geophysics and can effectively solve tasks of geological mapping in harsh weather conditions of Antarctica. It can adequately replace conventional aeromagnetic surveys that are now done using manned aircraft.
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Date submitted2024-05-11
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Date accepted2025-01-28
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Date published2025-03-21
Research and development of technology for the construction of snow airfields for accommodating wheeled aircraft in Antarctica
- Authors:
- Sergey P. Polyakov
- Sergey V. Popov
Construction of a new wintering complex at the Antarctic Vostok Station required prompt delivery of builders and mechanics to Progress Station to move them further to the work area. To solve this major logistical issue, a new landing site, later named Zenit, certified for accommodating heavy wheeled aircraft, was prepared in the Progress Station area from March to August 2022. Its snow pavement slab with a total area of 350 thousand m2 is from 100 to 120 cm high. It was made by applying snow layers with their subsequent compaction by a specially designed compaction platform for snow airfields suitable for heavy wheeled aircraft. As a result, the pavement has a surface hardness of at least 1 MPa. The layer from 30 to 60 cm has a hardness of at least 0.8 MPa, and the bottom layer at least 0.6 MPa. The first Il-76TD-90VD aircraft of the Russian company Volga-Dnepr was accommodated to the new runway on 7 November 2022. The aircraft landed in normal mode. The depth of the chassis wheels track after landing did not exceed 3 cm. The research provided in-depth understanding of the mechanisms for forming the supporting base of the runway from snow and ice in Antarctica. The experience gained can be used to solve similar issues in the Far North.
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Date submitted2023-10-02
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Date accepted2024-11-07
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Date published2025-03-20
Laboratory studies of hydraulic fracturing of intersecting boreholes in a non-uniform stress field
This study focuses on the features of hydraulic fracture propagation in intersecting boreholes in polymethyl methacrylate blocks in a non-uniform stress field. Glycerol aqueous solution and plasticine were used as the working fluids. According to linear fracture mechanics, a stress concentrator at the borehole intersection contributes to the beginning of crack formation, with further crack propagation occurring in the plane containing their axes. The relevance of this study is due to the search for innovative approaches and the development of technological solutions to address the issue of effective longitudinal crack formation and its further propagation in a rock mass under unfavourable stress field conditions. This paper provides a scheme of laboratory stand operation and a general view of the sealing packers used to isolate a specified interval when performing tests. The graphs of glycerol pressure versus injection time are presented, and the breakdown pressure in the blocks is specified. The shape of fractures formed during the indentation of plasticine into the borehole system was investigated. The findings of physical modelling indicate that longitudinal cracks are predominantly formed in the boreholes. The deviation of the crack trajectory from the vertical plane containing the borehole axes is primarily affected by the magnitude of the horizontal compressive stress field rather than the increase in the angle between them. In addition, the angles of inclination of the longitudinal crack plane measured at its intersection with the side face of the block are specified.
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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 submitted2021-12-20
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Date accepted2024-05-02
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Date published2024-08-26
A new formula for calculating the required thickness of the frozen wall based on the strength criterion
- Authors:
- Mikhail А. Semin
- Lev Yu. Levin
The study delves into the elastoplastic deformation of a frozen wall (FW) with an unrestricted advance height, initially articulated by S.S.Vyalov. It scrutinizes the stress and displacement fields within the FW induced by external loads across various boundary scenarios, notably focusing on the inception and propagation of a plastic deformation zone throughout the FW's thickness. This delineation of the plastic deformation zone aligns with the FW's state of equilibrium, for which S.S.Vyalov derived a formula for FW thickness based on the strength criterion. These findings serve as a pivotal launchpad for the shift from a one-dimensional (1D) to a two-dimensional (2D) exploration of FW system deformation with finite advance height. The numerical simulation of FW deformation employs FreeFEM++ software, adopting a 2D axisymmetric approach and exploring two design schemes with distinct boundary conditions at the FW cylinder's upper base. The initial scheme fixes both vertical and radial displacements at the upper base, while the latter applies a vertical load equivalent to the weight of overlying soil layers. Building upon the research outcomes, a refined version of S.S.Vyalov's formula emerges, integrating the Mohr – Coulomb strength criterion and introducing a novel parameter – the advance height. The study elucidates conditions across various soil layers wherein the ultimate advance height minimally impacts the calculated FW thickness. This enables the pragmatic utilization of S.S.Vyalov's classical formula for FW thickness computation, predicated on the strength criterion and assuming an unrestricted advance height.
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Date submitted2022-10-04
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Date accepted2024-03-05
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Date published2024-08-26
Localization and involvement in development of residual recoverable reserves of a multilayer oil field
During waterflooding of a multilayer oil field there is a constant deterioration of the structure and composition of residual reserves due to geological and technological reasons. The largest share of residual reserves is localized in pillars, which arise from uneven development of the production facility and are undrained or poorly drained zones. The results of a quantitative assessment of the distribution of residual oil reserves in the Middle and Upper Devonian deposits of the Romashkinskoe oil field of the Republic of Tatarstan are presented. A retrospective method is proposed to identify reserves by analyzing and summarizing historical exploration data and the long history of reservoir development, and a calculation algorithm is proposed to quantify them. It has been established that residual oil reserves are localized in rows of dividing and injection wells, as well as in the central rows of producing wells in a three-line drive, in abandoned and piezometric wells, in the areas adjacent to the zones of reservoir confluence, pinch-out, oil-bearing contours, distribution of reservoirs with deteriorated porosity and permeability properties. Depending on geological conditions, algorithms for selecting geological and technical measures to include localized reserves in development and forecasting production profiles were proposed. According to the proposed method, residual recoverable reserves were identified and a number of wells were recommended for experimental works on their additional recovery: in well 16 (hereinafter in the text, conventional well numbers are used) after isolation of overlying high-water-cut formations, the additional perforation was carried out and oil flow was obtained. Additional perforation in well 6 resulted in oil recovery during development as well. Thus, the developed approaches to identifying residual recoverable reserves and patterns of their spatial distribution can be recommended in other multilayer oil fields with a long history of development.
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Date submitted2023-03-14
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Date accepted2023-10-25
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Date published2024-04-25
Predictive assessment of ore dilution in mining thin steeply dipping deposits by a system of sublevel drifts
The purpose of research is the study of stress-strain state of marginal rock mass around the stope and predictive assessment of ore dilution with regard for changes in ore body thickness in mining thin ore deposits on the example of the Zholymbet mine. Study of the specific features of the stress-strain state development was accomplished applying the methodology based on numerical research methods taking into account the geological strength index (GSI) which allows considering the structural features of rocks, fracturing, lithology, water content and other strength indicators, due to which there is a correct transition from the rock sample strength to the rock mass strength. The results of numerical analysis of the stress-strain state of the marginal part of the rock mass using the finite element method after the Hoek – Brown strength criterion made it possible to assess the geomechanical state in the marginal mass provided there are changes in ore body thickness and to predict the volume of ore dilution. It was ascertained that when mining thin ore deposits, the predicted value of ore dilution is influenced by the ore body thickness and the GSI. The dependence of changes in ore dilution values on the GSI was recorded taking into account changes in ore body thickness from 1 to 3 m. Analysis of the research results showed that the predicted dimensions of rock failure zone around the stopes are quite large, due to which the indicators of the estimated ore dilution are not attained. There is a need to reduce the seismic impact of the blasting force on the marginal rock mass and update the blasting chart.
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Date submitted2022-07-10
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Date accepted2023-06-20
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Date published2024-02-29
Mathematical modeling of the electric field of an in-line diagnostic probe of a cathode-polarized pipeline
A mathematical model of the in-line control of the insulation resistance state for cathodically polarized main pipelines according to electrometry data is considered. The relevance of the work is caused by the opportunity to create in-line internal isolation defects indicators of the main pipelines for transported liquids that are good conductors and expand the functionality of monitoring and controlling cathodic protection systems of the main pipelines. Features of the mathematical model are: consideration of the electric conductivity of transported liquid influence on electric field distribution; consideration of the influence of external and internal insulating coating resistance; use of the electric field of an in-line diagnostic probe for quality control of internal insulation. Practical significance consists in the development of modeling methods for control subsystems of main pipeline protection against corrosion and the development of special mathematical and algorithmic support systems for monitoring and controlling the operating modes of the cathodic protection station of main pipelines.
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Date submitted2023-03-14
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Date accepted2023-06-20
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Date published2023-07-19
The wireless charging system for mining electric locomotives
The electric vehicles development has a high potential for energy saving: an energy-saving traffic control can reduce energy resource consumption, and integration with the power grid provides the ability of daily load pattern adjustment. These features are also relevant for underground mining. The critical element of vehicle-to-grid integration is the charging infrastructure, where wireless charging is promising to develop. The implementation of such systems in underground mining is associated with energy efficiency issues and explosion safety. The article discusses the development and research of a wireless charging system for mining electric locomotive A-5.5-600-U5. The analytic hierarchy process is used for justification of the circuitry and design solution by a comparison of different technical solutions based on energy efficiency and safety criteria. A complex computer model of the wireless charging system has been developed that gives the transients in the electrical circuit of a wireless charging system and the high-frequency field density distribution near the transmitting and receiving coils in a 3D setting. An approach to ignition risk evaluation based on the analysis of high-frequency field density in the charging area between the coils of the wireless charging system is proposed. The approach using a complex computer model is applied to the developed system. The study showed that the wireless charging system for mining electric locomotives operating in the gaseous-and-dusty mine is technically feasible and there are designs in which it is explosion safe.
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Date submitted2022-04-07
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Date accepted2023-04-21
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Date published2023-08-28
Development of a new assessment system for the applicability of digital projects in the oil and gas sector
Digital transformation is one of the global trends that has covered most sectors of the economy and industry. For oil and gas companies, the introduction of digital technologies has become not just a trend, but one of the factors for ensuring competitiveness and maintaining a stable position in the market in a rapidly changing macro environment. At the same time, despite the positive effects achieved, digital transformation is a complex process from the point of view of implementation and is associated with high technological, financial, and economic risks. The work aims to develop and test a new system for evaluating the applicability of digital projects in the oil and gas sector. The research methodology includes the application of the Gartner curve, methods of expert assessments, and tools for assessing the economic efficiency of investment projects. The developed assessment system is based on a comprehensive accounting of four components: the level of digital maturity of the company; compliance of the implemented technology with the goals and objectives of the organization; the level of reliability of the implemented technology; the level of innovation of the implemented project. Particular attention is paid to the practical testing of the proposed methodology based on the evaluation of a digital project implemented by a Russian oil and gas company.
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Date submitted2023-03-16
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Date accepted2023-06-20
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Date published2023-07-19
Energy efficiency of the linear rack drive for sucker rod pumping units
- Authors:
- Oksana Yu. Ganzulenko
- Ani P. Petkova
At present, in order to increase oil production and reduce economic costs in the development of marginal fields, the development of a cluster method using compact mobile drives of sucker rod pumping units (SRPU) is relevant. The aim of the work is to analyze the ways to improve the energy efficiency of the SRPU by reducing the loss of mechanical and electrical energy, to select the most energy-efficient compact drive for the development of marginal fields in the cluster method, to carry out the kinematic and strength calculations of the drive of the selected size, to develop an adaptive control system for a group of drives in the cluster development of drillings. According to the results of the performed calculations, the linear rack-and-gear drive has the highest efficiency of the drive mechanism. The kinematic and strength calculations of a linear rack-and-gear drive with a stroke length of 1120 mm and a load of up to 8 tons are presented. It was shown that the usage of a direct torque control system and a kinetic energy storage system for the SRPU drive elements and a rod string is an effective means of reducing energy costs in oil production from marginal fields. The use of the developed system for storing and redistributing the potential energy of the rods between the SRPUs that lift oil made it possible to eliminate fluctuations in the power consumption, reduce the power peak value by three times, the peak value of the current consumed from the electric network by two times, and reduce losses in the input converter and cables by three times.
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Date submitted2022-09-30
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Date accepted2023-04-03
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Date published2024-02-29
Optimization of the location of a multilateral well in a thin oil rim, complicated by the presence of an extensive gas cap
- Authors:
- Кirill О. Тomskii
- Mariya S. Ivanova
The specific share of the reserves of hard-to-recover hydrocarbon raw materials is steadily growing. The search for technologies to increase the hydrocarbon recovery factor is one of the most urgent tasks facing the oil and gas industry. One of the methods to expand the coverage of oil reserves and increase oil recovery is to use the technology of drilling multilateral wells with a fishbone trajectory. In the Russian Federation, the most branched well was drilled in the Republic of Sakha (Yakutia) at the Srednebotuobinskoye oil and gas condensate field. The main object of development is the Botuobinsky horizon (Bt reservoir). About 75 % of the geological reserves of the reservoir are concentrated in a thin oil rim with an average oil-saturated layer thickness of 10 m with an extensive gas cap. This circumstance is one of the main complicating factors in the development of the Srednebotuobinskoye oil and gas condensate field. For such complex wells, one of the most important design stages is to determine the optimal location of the fishbone well in an oil-saturated reservoir. The article shows the results of sector modeling in the conditions of the Srednebotuobinskoye field to determine the optimal location of multilateral wells using Tempest simulator.
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Date submitted2022-08-24
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Date accepted2023-02-15
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Date published2023-08-28
Modelling of the stress-strain state of block rock mass of ore deposits during development by caving mining systems
The article is devoted to the analysis of approaches to modeling the stress-strain state of a block rock mass in the vicinity of a single mine workings and in the area of rock cantilever influence during the development of the Khibiny apatite-nepheline deposits. The analysis of the existing in international engineering practice ideas about tectonic disturbances as a geomechanical element and the experience of predicting the stress-strain state of a block rock mass was carried out. On the basis of the analysis, the formulation of the basic modeling tasks is carried out and its main results are presented. Methodological recommendations for solving similar problems were developed.
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Date submitted2021-10-31
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Date accepted2023-03-02
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Date published2023-12-25
Improvement of technological schemes of mining of coal seams prone to spontaneous combustion and rock bumps
On the example of the Alardinskaya mine, the problem of underground mining of seams prone to spontaneous combustion and rock bumps in the conditions of the Kondomsky geological and economic region of the Kuznetsk coal basin is considered. The contradictions in the requirements of regulatory documents for the width of the inter-panel coal pillars in the mining of seams with longwalls in conditions of endogenous fire hazard and in the mining of seams that are dangerous due to geodynamical phenomena are discussed. These contradictions impede the safe mining of seams using traditionally used layouts with the danger of spontaneous combustion of coal and rock bumps. A mining-geomechanical model is presented, which is used for numerical three-dimensional simulation of the stress-strain state of a rock mass with various layouts for longwall panels using the finite element method. The results of the numerical analysis of the stress state of the rock mass immediately before the rock bump are presented, and the main factors that contributed to its occurrence during the mining of the seam are established. A dangerous degree of stress concentration in the coal seam near the leading diagonal entries is shown, especially in conditions of application of abutment pressure from the edge of panels’ gob. The analysis of the features of stress distribution in the inter-panel pillar at different widths is carried out. Recommendations for improving the layout for the development and mining of coal seams that are prone to spontaneous combustion and dangerous in terms of rock bumps in the conditions of Alardiskaya mine have been developed. The need for further studies of the influence of pillars for various purposes, formed during the mining of adjacent seams, on the stress-strain state of previously overmined and undermined seams is shown.
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Date submitted2022-06-20
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Date accepted2023-01-10
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Date published2023-08-28
Laboratory, numerical and field assessment of the effectiveness of cyclic geomechanical treatment on a tournaisian carbonate reservoir
Results are discussed for evaluation of effectiveness of the cyclic geomechanical treatment (CGT) on a Tournaisian carbonate reservoir. Analysis of laboratory experiments performed according to a special program to assess permeability changes for Tournaisian samples under cyclic changes in pore pressure is presented. The main conclusion is the positive selectivity of the CGT: an increase in permeability is observed for samples saturated with hydrocarbons (kerosene) with connate water, and maximal effect is related to the tightest samples. For water-saturated samples, the permeability decreases after the CGT. Thus, the CGT improves the drainage conditions for tight oil-saturated intervals. It is also confirmed that the CGT reduces the fracturing pressure in carbonate reservoirs. Using flow simulations on detailed sector models taking into account the results of laboratory experiments, a possible increase in well productivity index after CGT with different amplitudes of pressure variation was estimated. Results of a pilot CGT study on a well operating a Tournaisian carbonate reservoir are presented, including the interpretation of production logging and well testing. The increase in the well productivity index is estimated at 44-49 % for liquid and at 21-26 % for oil, with a more uniform inflow profile after the treatment. The results of the field experiment confirm the conclusions about the mechanisms and features of the CGT obtained from laboratory studies and flow simulations.
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Date submitted2022-04-08
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Date accepted2023-03-02
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Date published2023-04-25
Geochemical properties and transformation of the microelement composition of soils during the development of primary diamond deposits in Yakutia
Extraction of diamonds from primary deposits in Siberia is associated with the development of kimberlite pipes in challenging environmental conditions, accompanied by a complex impact on the environment. The article presents the results of monitoring the soil cover of the Nakyn kimberlite field in the Yakutia diamond province, which is affected by the facilities of the Nyurba Mining and Processing Division. Development of primary diamond deposits has a large-scale impact on the subsoil, topography, and soil cover: creation of the world's largest quarries, formation of dumps more than 100 m high, arrangement of extensive tailings, formation of solid and liquid industrial wastes of various chemical composition. The research is aimed at studying the spatial and temporal patterns of the technogenic impact on the soil cover, identifying the nature and level of transformation of the microelement composition of soils based on the analysis of the intra-profile and lateral distribution of mobile forms of trace elements. The study targets in 2007-2018 were zonal types of permafrost soils of northern taiga landscapes, cryozems, occupying 84 % of the total study area, which are characterized by biogenic accumulation of mobile forms of Ni, Mn, and Cd in the upper AO, A cr horizons, and Cr, Ni, Co, Mn, Cu in the suprapermafrost CR horizon. We found out that the contamination of the soil cover of the industrial site at the Nyurba Mining and Processing Division is of a multielement nature with local highly to very highly contaminated areas. Over a ten-year observation period, areas of stable soil contamination are formed, where the main pollutants are mobile forms of Mn, Zn, Ni. We suggest that against the background of a natural geochemical anomaly associated with trap and kimberlite magmatism, technogenic anomalies are formed in the surface horizons of soils. They are spatially linked to technogenically transformed landscapes. One of the sources of pollutants is the dispersion of the solid phase of dust emissions in the direction of the prevailing winds, which leads to the formation of soils with abnormally high contents of mobile forms of Mn, Zn, Ni.
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Date submitted2022-07-15
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Date accepted2022-12-13
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Date published2023-02-27
Mathematical modelling of displacement during the potash ores mining by longwall faces
In favourable mining conditions, in particular at the Starobinskoye potash deposit (Belarus), longwall mining systems are used. They cause a high human-induced load on the subsoil, including intense deformation of the ground surface. The presented investigations are aimed at studying the dynamics of the ground surface displacement during the longwall face advance. Mathematical modelling was carried out in an elastic-plastic formulation with numerical implementation by the finite element method. The condition for the roof rocks collapse was opening of the contact between the seams when its boundaries were reached by shear fractures or formation of the tensile stresses area at the outcrop. With the working front advance, an increase in subsidence is observed, followed by its stabilization to a value determined by the process parameters of mining operations and the physical and mechanical properties of collapsed rocks. In this case, each point of the ground surface experiences sign-alternating horizontal deformations: when the front approaches, it causes tension, and when it moves away, compression. The obtained results of mathematical modelling are in good agreement with the data of instrumental measurements of the ground surface displacements, which indicates the adequate description of the rock mass deformation during the slice excavation of sylvinite seams by longwall faces.
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Date submitted2022-11-08
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Date accepted2022-11-21
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Date published2023-02-27
Assessment of the role of the state in the management of mineral resources
Mineral resources as natural capital can be transformed into human, social and physical capital that guarantees the sustainable development of a country, exclusively through professional public management. Public management of a country's mineral resource potential is seen as an element of transnational governance which provides for the use of laws, rules and regulations within the jurisdictional and sectoral capabilities of the state, minimising its involvement as a producer of minerals. The features of the ideology of economic liberalism, which polarises the societies of mineral-producing countries and denies the role of the state as a market participant, have been studied. The analysis of the influence of the radical new order of neoliberal world ideology on the development of the extractive sector and state regulation has been presented.
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Date submitted2021-09-01
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Date accepted2022-10-07
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Date published2022-12-29
Parameter determination of the method of directional unloading of the reservoir based on physical modelling on a true triaxial loading setup
The article presents a theoretical and experimental substantiation of the method of directional unloading of the reservoir in fields with low-permeability reservoirs. The relevance of the article is due to the reduction of hydrocarbon resources in modern conditions and the need to create new efficient environmentally friendly technologies to develop hydrocarbon deposits with hard-to-recover reserves, primarily with low-permeability reservoirs. The results of a theoretical study of the stress-strain state in the vicinity of a well, both cased and open, are presented. They are necessary to develop programs for laboratory testing of core specimens from the studied fields. A technique for physical modelling of deformation processes in the bottomhole zone with a decrease in pressure at the well bottom in a true triaxial loading unit is described in order to determine the parameters of the process impact on the formation reservoir, leading to an increase in well productivity. The method was applied to the conditions of the low-permeability reservoir at the Verkhneviluchanskoye oil and gas condensate field in the southwest of the Republic of Sakha (Yakutia). Expe-rimental studies were carried out on a unique scientific unit for true triaxial loading, created at the IPMech RAS, the Triaxial Independent Loading Test System. The directional unloading method was adapted for the studied field, the process parameters of successful application of the method were determined: the bottomhole design, the drawdown values necessary to increase the permeability of the bottomhole formation zone.
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Date submitted2022-09-15
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Date accepted2022-11-17
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Date published2022-12-29
Comprehensive assessment of hydraulic fracturing technology efficiency for well construction during hydrocarbon production
The oil and gas industry has been an integral and fundamental sector of the Russian economy for the past few years. The main problems of this industry have traditionally been the deteriorating structure of oil reserves; depreciation of main assets; slowdown and decline in oil production. Recently these have been complicated by a number of new negative trends related to underinvestment, limited financial resources, deteriorating access to new equipment and technologies. The task of the research is to make a comprehensive assessment of hydraulic fracturing technology during well construction and to increase the recovery and intensification of hydrocarbons production. In this research, modeling techniques were used to assess the productivity of each fracture. Geophysical methods (seismic survey) were used to determine the geomechanical properties of the formation. Comprehensive assessment of hydraulic fracturing technology during well construction was carried out, which allowed to increase vertical permeability and unite disparate parts of the reservoir in practice, and to determine the development efficiency of the hydrocarbon field.
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Date submitted2021-12-21
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Date accepted2022-06-20
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Date published2022-11-10
Scientific justification of the perforation methods for Famennian deposits in the southeast of the Perm Region based on geomechanical modelling
The article presents the results of analysing geological structure of the Famennian deposits (Devonian) in the Perm Region. Numerical modelling of the distribution of inhomogeneous stress field near the well was performed for the two considered types of perforation. With regard for the geometry of the forming perforation channels, numerical finite element models of near-wellbore zones were created considering slotted and cumulative perforation. It is ascertained that in the course of slotted perforation, conditions are created for a significant restoration of effective stresses and, as a result, restoration of reservoir rock permeability. Stress recovery area lies near the well within a radius equal to the length of the slots, and depends on the drawdown, with its increase, the area decreases. From the assessment of failure areas, it was found that in case of slotted perforation, the reservoir in near-wellbore zone remains stable, and failure zones can appear only at drawdowns of 10 MPa and more. The opposite situation was recorded for cumulative perforation; failure zones near the holes appear even at a drawdown of 2 MPa. In general, the analysis of results of numerical simulation of the stress state for two simulated types of perforation suggests that slotted perforation is more efficient than cumulative perforation. At the same time, the final conclusion could be drawn after determining the patterns of changes in permeability of the considered rocks under the influence of changing effective stresses and performing calculations of well flow rates after making the considered types of perforation channels.
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Date submitted2022-05-18
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Date accepted2022-07-21
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Date published2022-11-10
Improving the method for assessment of bending stresses in the wall of an underground pipeline
- Authors:
- Ruslan V. Aginey
- Alexei A. Firstov
Brief information about modern methods for determining the bending stresses of the extended sections of underground main pipelines without access to the pipeline generatrix is given. The necessity of modernizing methods based on determining the configuration of the pipeline axis from the soil surface with subsequent calculation of bending stresses based on the obtained data is substantiated. A mathematical model that allows to calculate the optimal parameters for surveying the axis of the pipeline from the soil surface for a pipeline of arbitrary configuration and depth, when planning a study, is proposed. Bench tests of the BITA-1 pipeline finder were carried out to determine the error in measuring the depth of the pipeline axis. It is proved that the deviations of the pipeline finder data relative to the true values in narrow depth intervals follow a normal distribution and do not change their sign. The confidence intervals of the error in determining the depth of the pipeline axis for the BITA-1 device are presented.
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Date submitted2022-01-31
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Date accepted2022-09-06
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Date published2022-11-10
Filtration studies on cores and sand packed tubes from the Urengoy field for determining the efficiency of simultaneous water and gas injection on formation when extracting condensate from low-pressure reservoirs and oil from oil rims
- Authors:
- Nikolay A. Drozdov
Oil rims as well as gas condensate reservoirs of Russia's largest Urengoy field are developed by depletion drive without formation pressure maintenance, which has led to serious complications in production of oil, gas and condensate. In addition, field development by depletion drive results in low values of oil and condensate recovery. These problems are also relevant for other oil and gas condensate fields. One of the possible solutions is simultaneous water and gas injection. Rational values of gas content in the mixture for affecting gas condensate fields and oil rims of oil and gas condensate fields should be selected using the data of filtration studies on core models. The article presents the results of filtration experiments on displacement of condensate and oil by water, gas and water-gas mixtures when simulating the conditions of the Urengoy field. Simultaneous water and gas injection showed good results in the experiments on displacement of condensate, residual gas and oil. It has been ascertained that water-gas mixtures with low gas content (10-20 %) have a better oil-displacement ability (9.5-13.5 % higher) than water. An experiment using a composite linear reservoir model from cemented core material, as regards the main characteristics of oil displacement, gave the same results as filtration experiments with sand packed tubes and demonstrated a high efficiency of simultaneous water and gas injection as a method of increasing oil recovery at oil and gas condensate fields.
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Date submitted2021-12-19
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Date accepted2022-07-21
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Date published2022-11-10
Increasing the content of coarse fractions in the mined coal mass by a combine using paired cuts
The main volume of coal is mined underground using shearers. In modern shearers, auger actuators are mainly used, which are distinguished by the simplicity of design, manufacturability and reliability. However, in the process of separating coal from mass by cutting, the yield of fine grades is 40-50 % of the total production volume. Therefore, the search and development of technical solutions that provide an increase in the yield of large fractions in the process of coal mining with auger shearers is an urgent task. Traditionally, this problem is solved by increasing the thickness of the slices, which is achieved by installing cutters with a larger radial reach and increasing the shearer feed rate. An unconventional way to increase the cross section of slices by forming energy-efficient paired and group slices with mutual superposition of stress fields in the mass from the action of neighboring cutters is considered. The results of modeling the process of cutting coal confirm that an increase in the efficiency of destruction of the rock mass by the cutters of the auger executive bodies of the shearer can be achieved by a complex technical solution, including the formation of paired cuts and combined stress zones in the rock mass. As a result, the output of large fragments when cutting with paired cutters increases by 1.3-1.8 times compared with cutting with a single cutter.