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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 submitted2023-06-25
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Date accepted2024-11-07
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Date published2025-02-25
Study of wormhole channel formation resulting from hydrochloric acid treatment in complex-type reservoirs using filtration and X-ray computed tomography methods
- Authors:
- Andrei A. Аbrosimov
The primary function of hydrochloric acid treatment (HAT) is to create the maximum number of high-conductivity channels in the near-wellbore zone of the reservoir to restore its permeability and enhance hydraulic connectivity between the undisturbed part of the formation and the well. The objective of this study is to physically model HAT on core samples from the Orenburg oil and gas condensate field and to research the impact of such treatment on the structure of the pore space of rocks related to complex-type reservoirs. The complexity of the rock's pore space and the low permeability of the formations are distinguishing features of the study object. For this reason, HAT is a widely applied method for production intensification, necessitating the verification of acid injection rates, where the success criterion is the formation of high-conductivity filtration channels (wormholes) in the near-wellbore zone. These channels significantly expand the drainage area of wells, thereby bringing additional reservoir sections into development. The study examined the characteristics of filtration channel development resulting from acid treatment. Their structure was characterized and analyzed using X-ray computed tomography. The complex study confirmed the accuracy of the selected injection rate and provided practical recommendations for enhancing the efficiency of HAT.
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Date submitted2023-08-02
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Date accepted2023-12-27
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Date published2024-04-25
Justification of the approaches to improve management strategy of the mining system based on the analysis of data on the mining of complex structural rock blocks
Long-term activity of mining enterprises causes the necessity to substantiate the strategies of management of the mining and technical system functioning in terms of improvement of ore quality control, which is determined by its change in the course of field development due to the priority development of the main reserves and, as a consequence, forced transition to the mining of complex structural rock blocks with a decrease in the recovery percentage, which is typical in case the ore component meets the requirements of the feasibility study in terms of grade at substandard capacity. In this case, it is possible to identify the recovery percentage and the potential for its increase by analyzing the long-term activity of the mining and industrial enterprise, namely, by analyzing the data of mining complex structural rock blocks with the subsequent establishment of the relationship between the primary data on mining and geological conditions and information on the quality of the mineral obtained from the technological equipment. Therefore, the purpose of the research was to substantiate the necessity of improving the management strategy of the mining-technical system functioning, which consists in the fact that on the basis of analyzing the mining data of complex structural rock blocks it is possible to determine the ore mass losses and their quantity and to lay the basis for the development of decisions on its extraction. For this purpose, the collected data on the mining of complex structural rock blocks, accounting the geological and industrial type of extracted ores, were considered in modeling the conditions and studying the parameters of technological processes, the implementation of which provides additional products. It was revealed that the ore mass from substandard thickness layers is delivered to the dumps, and ore mass losses have been estimated at 25-40 % per year. It is proved that determination of ore mass losses based on the analysis of data on mining of complex structural rock blocks, as well as timely solution of this issue can significantly increase the production efficiency of mining and technical system. Taking into account for the results obtained, the options for optimizing the production of the mining and engineering system were proposed.
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Date submitted2021-01-21
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Date accepted2023-09-20
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Date published2023-12-25
Adaptation of transient well test results
Transient well tests are a tool for monitoring oil recovery processes. Research technologies implemented in pumping wells provide for a preliminary conversion of measured parameters to bottomhole pressure, which leads to errors in determining the filtration parameters. An adaptive interpretation of the results of well tests performed in pumping wells is proposed. Based on the original method of mathematical processing of a large volume of field data for the geological and geophysical conditions of developed pays in oil field, multidimensional models of well flow rates were constructed including the filtration parameters determined during the interpretation of tests. It is proposed to consider the maximum convergence of the flow rate calculated using a multidimensional model and the value obtained during well testing as a sign of reliability of the filtration parameter. It is proposed to use the analysis of the developed multidimensional models to assess the filtration conditions and determine the individual characteristics of oil flow to wells within the pays. For the Bashkirian-Serpukhovian and the Tournaisian-Famennian carbonate deposits, the influence of bottomhole pressure on the well flow rates has been established, which confirms the well-known assumption about possible deformations of carbonate reservoirs in the bottomhole areas and is a sign of physicality of the developed multidimensional models. The advantage of the proposed approach is a possibility of using it to adapt the results of any research technology and interpretation method.
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Date submitted2022-10-24
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Date accepted2023-03-03
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Date published2023-04-25
Use of clay-containing waste as pozzolanic additives
Growing productivity of mining and processing enterprises entails an increase in the volumes of liquid tailings impoundments and upstream impoundments of ore processing waste. Enterprises face the challenge of minimizing the environmental impact of waste and guaranteeing the sanitary and epidemiological safety of population. The article presents a possibility of recycling one type of such waste (clay-containing concentration tailings of apatite-nepheline and sylvinite ores, coal beneficiation tailings) by using them after preliminary thermochemical treatment as pozzolanic additives to cements and concretes, including concrete mixtures used for soil stabilization, development of territories, reclamation of mine workings, as a component of the insulating layer of landfills for the disposal of municipal solid waste. An analysis of the phase changes of kaolinite, one of the main minerals that make up clay-containing waste, in the temperature range of 200-1,000 °С showed that a change in its mineral form during heat treatment is the main factor in changing its pozzolanic activity. The effect of heat treatment of clay minerals at temperature of 700-800 °C on their pozzolanic activity, estimated by the ability to absorb calcium hydroxide (0.7 g Ca(OH) 2 per 1 g of modified kaolinite), is considered. It is shown that the addition of heat-treated samples (20 % by weight) improves the quality of cement increasing its activity by 15 %, in comparison with the use of unmodified clay minerals. It was proved experimentally that partial replacement of Portland cement with thermally modified kaolinite increases the strength of consolidating stowing mixture by up to 15 %. This approach to processing of ores containing layered silicates, which provides for thermochemical modification of run-of-mine ore, intensifies the processes of tailings thickening and filtering.
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Date submitted2022-10-19
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Date accepted2023-02-14
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Date published2023-04-25
Electric steelmaking dust as a raw material for coagulant production
The paper describes the issues associated with waste generated during steel production and processing, in particular the dust from electric arc furnaces (EAF). An effective solution for the disposal of such waste is its involvement in processing to obtain valuable products. This paper studies the physical and chemical properties of EAF dust produced during the smelting of metallized pellets and captured by the dust and gas cleaning system of the steel-smelting shop at the Oskol Electrometallurgical Combine, Belgorod Region. The results obtained in the study of the chemical and disperse compositions of dust, the microstructure of the surface made it possible to propose the use of dust as a raw material for coagulant production. The conditions of acid-thermal treatment of dust are determined, contributing to the partial dissolution of iron (II), (III), and aluminium compounds, which ensure the coagulation processes during wastewater treatment. Model solutions show high efficiency (> 95 %) of water treatment from heavy metal ions by modified EAF dust.
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Date submitted2021-03-24
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Date accepted2022-12-15
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Date published2023-08-28
Composite model of seismic monitoring data analysis during mining operations on the example of the Kukisvumchorrskoye deposit of AO Apatit
Geomechanical monitoring of the rock mass state is an actively developing branch of geomechanics, in which it is impossible to distinguish a single methodology and approaches for solving problems, collecting and analyzing data when developing seismic monitoring systems. During mining operations, all natural factors are subject to changes. During the mining of a rock mass, changes in the state of structural inhomogeneities are most clearly manifested: the existing natural structural inhomogeneities are revealed; there are movements in discontinuous disturbances (faults); new man-made disturbances (cracks) are formed, which are accompanied by changes in the natural stress state of various blocks of the rock mass. The developed method for evaluating the results of monitoring geomechanical processes in the rock mass on the example of the United Kirovsk mine of the CF AO Apatit allowed to solve one of the main tasks of the geomonitoring system – to predict the location of zones of possible occurrence of dangerous manifestations of rock pressure.
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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 submitted2021-02-09
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Date accepted2021-07-27
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Date published2021-10-21
Development of an algorithm for determining the technological parameters of acid composition injection during treatment of the near-bottomhole zone, taking into account economic efficiency
Relevance of the research is due to the low proportion of successful hydrochloric acid treatments of near-bottomhole zones of carbonate reservoirs in the Perm region caused by insufficiently careful design and implementation of measures to stimulate oil production. Within the framework of this article, the development of a program is presented, which is based on an algorithm that allows determining the volume and rate of injection for an acid composition into a productive formation corresponding to the maximum economic efficiency during hydrochloric acid treatment. Essence of the proposed algorithm is to find the greatest profit from measures to increase oil recovery, depending on the cost of its implementation and income from additionally produced oil. Operation of the algorithm is carried out on the principle of enumerating the values of the volume and rate of injection for the acid composition and their fixation when the maximum difference between income and costs, corresponding to the given technological parameters of injection, is reached. The methodology is based on Dupuis's investigations on the filtration of fluids in the formation and the results of the experiments by Duckord and Lenormand on the study of changes in the additional filtration resistance in the near-well zone of the formation when it is treated with an acid composition. When analyzing and including these investigations into the algorithm, it is noted that the developed technique takes into account a large number of factors, including the lithological and mineralogical composition of rocks, technological parameters of the injection of a working agent and its properties, well design, filtration properties of the formation, properties of well products. The article provides an algorithm that can be implemented without difficulty using any programming language, for example, Pascal. Selection of the optimal values for the volume and rate of injection is presented in this paper, using the example of a production well at the Chaikinskoye oil field, located within the Perm region. Introduction of the developed algorithm into the practice of petroleum engineering will allow competent and effective approach to the design of hydrochloric acid treatments in carbonate reservoirs without a significant investment of time and additional funds.
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Date submitted2021-03-10
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Date accepted2021-05-21
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Date published2021-09-20
Influence of heat treatment on the microstructure of steel coils of a heating tube furnace
- Authors:
- Vladimir Yu. Bazhin
- Bashar Issa
Transportation and refining of heavy metal-bearing oil are associated with the problems of localized destruction of metal structures and elements due to corrosion. In the process of equipment operation, it was revealed that premature failure of steel coils of heating tube furnaces at oil refineries and petrochemical plants was associated with insufficient strength and corrosion resistance of the steelwork. The study of the effect that structure and phase composition of 15KH5M-alloy steel elements of heating furnaces at oil refineries have on the corrosion properties, associated with mass loss and localized destructions in the process of heat treatment, allows to develop protective measures and determine heating modes with a rate-limiting step of oxidation. The rate of various corrosion types of 15KH5M steel is used as an indicator to assess the effectiveness of the applied modes of coil heat treatment in order to increase their corrosion resistance and improve their operational characteristics. Conducted experiments on heat treatment of certain steel coil sections allowed to determine rational heating modes for the studied coils, which made it possible to reduce their mass loss and increase corrosion resistance of working surfaces in the process of operation. Proposed heat treatment of steel coils at specified intervals of their operation in the tube furnaces creates conditions for their stable performance and affects the degree of industrial and environmental safety, as well as reduces material costs associated with the repair and replacement of individual assemblies and parts of tube furnaces.
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Date submitted2020-06-02
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Date accepted2021-05-21
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Date published2021-09-20
Analysis of technological schemes for creating a geodetic control at the industrial site
The article highlights the issues of creating with the necessary accuracy a planned control on the industrial site of the engineering structures under construction using satellite technologies and total stations. Depending on the design features of the engineering structures under construction, as well as the technological scheme for the installation of building constructions and industrial equipment, various schemes for creating such control are considered, based on the application of the inverse linear-angular notch. Errors in the source data are one of the main errors that affect the accuracy of geodetic constructions, including the solution of the inverse linear-angular notch. When creating a geodetic network in several stages, the errors of the initial data of the first stage affect the values of the root-mean-square errors (RMS) of determining the position of the second stage points, the errors of which affect the value of the RMS of the position of the third stage points, etc. The reason for their occurrence is the errors of geodetic measurements that occur at each stage of control creating, as well as the stability violation of the points during the production of excavation, construction and installation works. When determining the coordinates of a separate project point at the stage of its removal in-situ by a total station, the entire network is not equalized in the vast majority of cases, and the coordinates of the starting points to which the total station is oriented are considered error-free. As a result, the RMS determination of the points coordinates of the control network or the removal of the design points of the elements of building structures and equipment will also be considered satisfying the requirements, i.e. the measurement accuracy will be artificially overestimated and will not correspond to the actual one obtained. This is due to the fact that the accumulation of errors in the initial data is not taken into account when the number of steps (stages) of control creating increases. The purpose of this work is to analyze the influence of measurement errors and initial data when creating a geodetic control on an industrial site by several stages of its construction based on inverse linear-angular notches and a priori estimation of the accuracy of the determined points position.
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Date submitted2020-06-23
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Date accepted2021-03-02
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Date published2021-04-26
Automated digitization of radial charts
Radial charts were commonly used in the industry to allow retrospective assessment of technological parameters. Today it is relevant to digitize the obtained data in order to simplify the automation of technological processes. Digitization of radial charts by means of standard methods is carried out with the help of human labor at significant time costs. The article proposes an automated method for digitizing radial charts using software, developed in the LabVIEW programming environment. The results of processing radial charts are displayed on the screen in numerical and graphical form, and can also be exported to a file (for example, to Notepad or MS Excel). The presented technique can be applied to images obtained on a color or black-and-white scanner, which minimizes geometric distortions, associated with the conversion of a paper document into electronic form, and ensures recognition quality of the clear plot line with an average relative error of up to 3 %. In case of ink fading or perspective photos of the diagram, the value of relative error can reach 8 %, as a result of which additional manual correction of the data will be required.
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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.
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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 submitted2019-07-11
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Date accepted2019-09-04
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Date published2019-12-24
Recent scientific research on electrothermal metallurgical processes
- Authors:
- E. Baake
- V. A. Shpenst
A wide range of industrial metallurgical heating and melting processes are carried out using electrothermal technologies. The application of electrothermal processes offers many advantages from technological, ecological and economical point of view. Although the technology level of the electro heating and melting installations and processes used in the industry today is very high, there are still potentials for improvement and optimization due to the increasing complexity of the applications and the strong requirements regarding the performance and quality of the products but also regarding the reduction of time and costs for the development of new processes and technologies. In this paper recent applications and future development trends for efficient heating and melting by electrothermal technologies in metallurgical processes are described along selected examples like induction heating for forging or rolling of billets, heat treatment of strips and plates, press-hardening processes, induction surface hardening of complex geometries, induction welding as well as induction melting processes.
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Date submitted2019-05-20
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Date accepted2019-07-12
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Date published2019-10-23
Development of Manufacturing Technology for High-Strength Hull Steel Reducing Production Cycle and Providing High-Quality Sheets
The article presents the results of scientific research and industrial experiments aimed at the development of technology to reduce the production cycle of high-strength hull steel. The technology includes an improved reduced heat treatment of ingots made using rare-earth metals and uphill teeming of large sheet ingots. The proposed technology for the preliminary heat treatment of ingots eliminates the high-temperature phase re- crystallization operation, which is unnecessary, according to the authors, since it does not allow partial crushing (grinding) of the metal dendritic structure and homogenization. When using the proposed technology of reduced pre- treatment, phase and structural stresses are sharply reduced. Experiments have shown that the modification of steel with rare-earth metals has a positive effect on the crystallization of ingots, changing the macro- and microstructure of alloy steel. The developed manufacturing technology of high-strength hull steel provides a high level of sheet quality and a reduction in the production cycle time by 10-12 %.
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Date submitted2019-03-11
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Date accepted2019-05-11
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Date published2019-08-23
Estimate of Radial Drilling Technology Efficiency for the Bashkir Operational Oilfields Objects of Perm Krai
- Authors:
- S. V. Galkin
- A. A. Kochnev
- V. I. Zotikov
The radial drilling technology efficiency for carbonate bashkir deposits of Perm Krai is considered. The geological structure of a productive part of bashkir layer is characterized by high degree of heterogeneity that promotes while drilling radial channels involvement in development additional interlayers that earlier was not drained. During the analysis the main geological process parameters affecting drilling technology efficiency were revealed. According to the dynamics of average daily oil production growth, palettes were built to forecast additional oil production as a result of radial drilling activities. Using the pallets, it is possible to predict the total additional oil production, well operating time with the effect of radial drilling and average daily oil production growth for each year. It was found that hydrochloric acid treatments performed on wells prior to radial drilling significantly reduce the effectiveness of radial drilling technology. For such wells, the value of the correction is statistically substantiated, which reduces the predictive estimate of the increase in oil production. A model was built to assess the increase in oil production in the first year after the event and an algorithm for calculating the total additional oil production was developed using linear discriminant analysis. For the resulting model, errors are calculated that are compared with the forecast efficiency of standard methods for oil-producing enterprises. This model shows a much more accurate correspondence of forecast results to actual technology application results. The probability of the event high efficiency increases significantly with a more detailed approach to the selection of wells for radial drilling. According to the forecast methodology, the technology’s efficiency was calculated and recommendations for its implementation for the wells of the Bashkir production objects were made in the interests of an oil-producing enterprise.
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Date submitted2018-07-12
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Date accepted2018-09-09
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Date published2018-12-21
Application of the theory of wavelets for compression and filtration of geoinformation
- Authors:
- A. S. Yarmolenko
- O. V. Skobenko
The purpose of the article is to develop a detailed and accessible technology for the application of wavelets in the processing of geo-information, the subject of research is wavelet-based filtering and compression of geo-information. The research methodology is based on the modern theory of wavelets in the light of linear algebra. Research methods involve study and generalization, abstraction, formalization, mathematical modeling using computer programs compiled by the authors. After the introduction and formulation of the problem, the basic positions of linear algebra are presented, on which the content of the article is based when constructing orthonormal bases in one- and two-dimensional cases. First, the application of the general theory to the decomposition of the vector of initial data in the Haar and Shannon bases is given. Further, on the basis of the Haar basis, orthonormal bases of wavelet transforms and filtering information are constructed. The procedure for creating wavelet filters by a sequence of convolutions, the use of MSA analysis for constructing an orthonormal basis of the wavelet transform is considered. Implemented the practical possibility of wavelet filtering based on specific programs for modeling geo-information data fields and images, data compression and filtering. The result of the work is the methods of constructing orthonormal bases by various methods of wavelet transform, based on which algorithms and corresponding computer programs for geoinformation compression are compiled using the example of terrain and photographic images. The efficiency of geoinformation compression and noise filtering using wavelets was investigated. A method has been developed for determining the value of a filter depending on the accuracy of the initial geo-information, illustrated by the example of calculating the filter value for compressing information about the heights of the terrain. The same technique is recommended for image filtering.
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Date submitted2018-05-03
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Date accepted2018-07-07
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Date published2018-10-24
Regularities of material destruction of the impactor in repeated single punch
- Authors:
- V. I. Bolobov
- Le Tkhan' Bin
The technique and the results of experiments on the study of the laws of the process of the cone-shaped tip of a freely falling impactor made of 38HM, U8, H12MF steels, subjected to typical heat treatment and additionally treated with cold, when they apply multiple (up to 10000) single impacts on granite under conditions approaching hydraulic impactor peaks. To explain the processes, we used the values of stresses σ к , arising at the contact area of the impactor and the rock, calculated using the developed mathematical model. It has been established that the process of wear of an impactor with multiple single blows proceeds in three stages separated by critical values, , which correspond to the strength characteristics of the material of the impactor demonstrated in these dynamic conditions. With a small number of strokes (n ≤ n * ) and the small size of the blunting area (stage I interaction) values σ c exceed of steel and it is exposed to local destruction at the contact site, which is recorded as a significant loss of the impactor’s mass; with n * < n ≤ n ** (stage II) the resulting stresses are not enough to destroy the material, but it is enough for its plastic deformation, accompanied by the movement of metal from the central part of the contact area to the peripheral and the destruction of part of the deformed metal by rock; with n > n ** (stage III) arising σ к do not reach the level and the decrease in the mass of the impactor is determined by the resistance of the steel to abrasion by the products of rock destruction, displaced by the impactor from the well. The treatment of impactors from all tested steels with cold leads to an increase in their wear resistance; The total depth of the holes punctured by the cold-treated H12MF steel impactor at the time of the interruption of the rock penetration is four times higher than that of the 38HM steel impactor subjected to typical heat treatment.
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Date submitted2018-05-04
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Date accepted2018-07-23
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Date published2018-10-24
Analysis of possible enhancementof properties of VK15 material used for drilling tools
- Authors:
- Yu. A. Kurganova
- K. S. Panina
- P. S. Beshenkov
Traditionally, when drilling hard and abrasive rocks, it is recommended to use a tungsten-cobalt hard alloy VK15. The analysis of information on the possibility of improving the potential of the material has demonstrated the existence of mechanisms that provide structural transformations that enhance its strength, hardness and toughness. The use of such technology instead of traditional methods will lead to an increase in the operating efficiency and durability of the tool. During the work, experimental samples of alloy VK15 were obtained by sintering in four different modes. Then their properties were analyzed. The results of the metallographic study carried out on the «Carl Zeiss» microscope made it possible to estimate the distribution of tungsten carbide grains in cobalt bon and show the grinding of the carbide phase. Thus, with traditional sintering, the amount of tungsten carbide grains with an average size of less than 1 μm in diameter from the entire size range reaches 19.5 %, while after additional heat treatment with a holding time of 1280 °C, the value was 41.5 %; 900 °C – 59.1 %; 600 °С – 54.5 %. The maximum improvement results were the following: hardness by 18 %, a coercive force by 49 %, and crack resistance by 11 % of the traditional alloy, there were achieved at 900-1280 °C. A hypothesis has been put forward on the formation of additional structural elements not detected by the methods of optical metallography. Studies of the topology and structure of the samples on an atomic force microscope confirmed the presence of nanoscale inclusions from 20 to 40 nm (presumably tungsten carbide) in a cobalt bond.For VK15, comparative studies of properties and analysis of the microstructure of experimental samples obtained by the traditional sintering and modified technology have shown that the sintering mode at 900 °C is a priority.
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Date submitted2018-05-21
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Date accepted2018-07-14
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Date published2018-10-24
Increasing the wear resistance of adapters and drill pipes by elec-tromechanical processing
The directions of the research on increasing the wear resistance of drill pipe locks, threaded joints and casing drill string have been defined: application of drill pipes from the nose-resistant surfacing to the lock with Russian and foreign materials (hardbanding); hardening of the surface layer of drill pipe locks by electromechanical processing; hardaning of the external and internal locking thread of drill pipes by electromechanical processing. Comparative tests of the wear resistance of various hardening materials (hardbanding) of Russian and foreign production and the drill pipe lock without surfacing have been made. The recommendations for increasing the wear resistance of threaded joints by the method of electromechanical processing are developed, which determine the ways of increasing the resource and reliability of drill pipes and sub-assemblies, the formation of unique properties of parts, reducing the labor-capacity of manufacturing and restoring parts, increasing the efficiency of enterprises and organizations, protecting the environment and creation of competitive products. The materials of the article are of practical value for specialists of various fields engaged in the issues of increasing the reliability of technological equipment. The production success of using wear resistant surfacing technology on the body of a drill pipe joint is due to the possibility of using relatively simple and mobile welding equipment, carrying out work in the places of use of a drilling tool or temporary (permanent) production bases with a small transport arm from the field, re-depositing surfacing materials restoration of drill pipe locks; a wide and growing list of companies that receive accreditation for the production of these works.
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Date submitted2017-12-29
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Date accepted2018-03-06
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Date published2018-06-22
Evaluation of signal properties when searching for cavities in soil under concrete slabs by radio detection stations of subsurface investigation
- Authors:
- G. V. Rudianov
- E. I. Krapivskii
- S. M. Danilev
A method of localization of concealed cavities on the basis of studying of the reflected electromagnetic impulses is considered in the paper. An issue of early detecting of concealed cavities in engineering facilities is a critical one due to a significant influence on further serviceability of a structure. Problems of localization of concealed cavities in the soil body under the concrete slabs of hydropower stations were studied; the results of ground radar detecting investigations of the cavities, physical simulation of a cavity as well as a mathematical modeling of a reflected signal are presented. Modern subsurface radar detection provides methods which allow to reliably detect concealed cavities in the soil. However, it is possible only in case of a clear boundary between the adjacent layers that conditions a jump of dielectric permeability. In the result of an abrupt change of dielectric permeability a reflected wave occurred; the existence of subsurface heterogeneity is conditioned by the properties of this wave. Moreover, the greater is the difference between the values of dielectric permeability in the adjacent layers, the larger amplitude the reflected wave will have. If the cavity is at the stage of forming, i.e. it is filled with the soil of reduced density, then there is no clear boundary at the border of the layers which will condition a gradual change of dielectric permeability with depth. In this case an amplitude of a reflected wave will be minimal and a formation signal will be masked out by jamming signals reflected from various heterogeneities. In such case to determine a cavity at the stage of forming seems to be impossible. To determine poor signals an analysis of a phase of a reflected signal may be used; phase alters in compliance with the reflection coefficient change pattern. The article contains information about signals reflected from the heterogeneities and a conclusion regarding a possibility of detecting cavities in the soil on the basis of a method of coherent processing of signals is made.
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Date submitted2018-01-23
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Date accepted2018-02-25
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Date published2018-06-22
Influence of post-welding processing on continuous corrosion rate and microstructure of welded joints of steel 20 and 30KHGSA
- Authors:
- A. M. Shchipachev
- S. V. Gorbachev
Welded joints of structure steels have lower corrosion resistance in comparison to base metal. To increase corrosion resistance of welded joints and heat-affected zone they use longtime and energy-consuming methods of thermal and mechanic processing. The article covers the possibility of using the superplasticity deformation (SD) effect for processing of welded joints. The effect of SD is that metals and alloys with a small grain size (of the order of 10 μm) under conditions of isothermal deformation at a certain temperature acquire the ability for unusually large plastic deformations while reducing the deformation resistance. Grain-boundary sliding during superplasticity provides a high degree of structural homogeneity. If the metal does not have the small grain size, then during isothermal deformation at appropriate temperature the SD effect will not be fully manifested but will cause relaxation of residual micro and macro strains, recrystallization, which can be used during processing of welded joints to ensure their full strength. There have been carried out the investigation of processing methods impact - SD, thermal cycling and influence of post-welding treatment on corrosion rate and microstructure of steels 20 and 30KhGSA. It is shown that after deformation in superplasticity mode there is low corrosion rate and more favorable microstructure in the studied samples of steel. Post-welding processing of welded joints in SD mode provides low tool loads and low energy costs.
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Date submitted2017-10-26
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Date accepted2017-12-25
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Date published2018-04-24
Conditions of austenite diffusional transformation in steel of Cr–3Ni–Mo–V-composition with high austenite stability
- Authors:
- V. V. Tsukanov
- N. V. Lebedeva
- Yu. M. Markova
The paper investigated the bainitic steel of 10KHN3MFA grade, which is characterized by the increased tendency to display structural heredity in the forgings with large cross-sections. The samples have been studied for kinetics of diffusional transformation process both under continuous cooling and isothermal conditions, as well as its microstructure. It is determined that in the range of subcritical temperatures with cooling from 900 °C in the studied steel, the initial stage of separation of the ferrite phase takes place. It is shown for the first time that the diffusional ferrite-pearlite transformation fades. Previously it was believed that the beginning of transformation under isothermal conditions proceeds to the end. It was found out that the transformation begins immediately after the beginning of isothermal holding, without the generally accepted incubation period.
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Date submitted2017-09-11
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Date accepted2017-10-30
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Date published2018-02-22
Provision of adhesion strength of gas-thermal coatings on piston rings of quarry transport engines
- Authors:
- Yu. Olt
- V. V. Maksarov
- V. A. Krasnyi
The main trend in the development of modern diesel engine manufacturign is the creation of high-powered, reliable and economical internal combustion engines (ICE), which are widely used in various industries, including mining machinery. The application of the methods of gas-thermal and gas-plasma coating for obtaining wear-resistant layers on piston rings for large internal combustion engines of quarry transport – diesel locomotives and dump trucks- is considered. It is shown that the abrasive-jet machining of base coat is widely used as a preparatory operation before coating process, and the roughness of the working surface of the rings after abrasive-jet machining has a significant impact on the adhesion strength of the coating with the base material. The selection of the surface roughness and the conditions of abrasive-jet machining for increasing the coating adhesion strength to the base coat significantly determines both the thickness of the coating and the reliability of the part itself. The aim of the paper is to investigate the dependence of the adhesion strength of a gas-thermal wear-resistant coating of piston rings of large engines of quarry transport, including dump trucks and diesel locomotives, from the roughness of the working surface after abrasive-jet machining, which in turn depends on its modes (distance to the nozzle exit section, the number of passes, the working air pressure, the shot change rate). The working surface adhesion strength of piston rings with diameter of 210 mm coated with molybdenum and steel wire composition was investigated by the twisting angle at which the coating peeled. It is shown that the roughness providing a twist angle greater than 35° should be more than 22 μm, which does not cause coating peeling off. Modes of abrasive-jet machining providing the specified values of roughness: working air pressure is 0.4 MPa, distance to the nozzle exit section is 110 mm, the number of passes is 2, and the shot changes after processing 40 mandrels.