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Date submitted2024-09-09
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Date accepted2024-11-05
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Date published2024-11-12
Acoustic emission criteria for analyzing the process of rock destruction and evaluating the formation of fractured reservoirs at great depths
In order to study the mechanism of destruction of rocks of various genesis and the formation of fractured reservoirs at great depths, laboratory studies of rock samples in the loading conditions of comprehensive pressure with registration of acoustic emission (AE) and parameters of the process of changing the strength and deformation properties of samples were carried out. The spatial distributions of the hypocenters of AE events for each sample were investigated. By the nature of the distributions, the fracture geometry is described, then visually compared with the position of the formed macrofractures in the samples as a result of the tests. The time trends of the amplitude distribution b, set by the Guttenberg – Richter law, were calculated, which were compared with the loading curves and trends of the calculated AE activity. Based on the analysis of the AE process for three types of rocks – igneous (urtites), metamorphic (apatite-nepheline ores), and sedimentary (limestones) – parameterization of acoustic emission was carried out to determine the features of the deformation process and related dilatancy. As a result, three types of destruction of samples were identified, their geometry and changes in strength and seismic criteria were established.
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Date submitted2023-08-14
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Date accepted2023-12-27
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Date published2024-12-25
Modelling of compositional gradient for reservoir fluid in a gas condensate deposit with account for scattered liquid hydrocarbons
In oil and gas reservoirs with significant hydrocarbon columns the dependency of the initial hydrocarbon composition on depth – the compositional gradient – is an important factor in assessing the initial amounts of components in place, the position of the gas-oil contact, and variations of fluid properties throughout the reservoir volume. Known models of the compositional gradient are based on thermodynamic relations assuming a quasi-equilibrium state of a multi-component hydrodynamically connected hydrocarbon system in the gravity field, taking into account the influence of the natural geothermal gradient. The corresponding algorithms allow for calculation of changes in pressure and hydrocarbon fluid composition with depth, including determination of the gas-oil contact (GOC) position. Above and below the GOC, the fluid state is considered single-phase. Many oil-gas-condensate reservoirs typically have a small initial fraction of the liquid hydrocarbon phase (LHC) – scattered oil – within the gas-saturated part of the reservoir. To account for this phenomenon, a special modification of the thermodynamic model has been proposed, and an algorithm for calculating the compositional gradient in a gas condensate reservoir with the presence of LHC has been implemented. Simulation cases modelling the characteristic compositions and conditions of three real oil-gas-condensate fields are considered. The results of the calculations using the proposed algorithm show peculiarities of variations of the LHC content and its impact on the distribution of gas condensate mixture composition with depth. The presence of LHC leads to an increase in the level and possible change in the type of the fluid contact. The character of the LHC fraction dependency on depth can be different and is governed by the dissolution of light components in the saturated liquid phase. The composition of the LHC in the gas condensate part of the reservoir changes with depth differently than in the oil zone, where the liquid phase is undersaturated with light hydrocarbons. The results of the study are significant for assessing initial amounts of hydrocarbon components and potential efficiency of their recovery in gas condensate and oil-gas-condensate reservoirs with large hydrocarbon columns.
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Date submitted2020-12-16
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Date accepted2021-07-27
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Date published2021-10-21
Features of the thermal regime formation in the downcast shafts in the cold period of the year
In the cold period of the year, to ensure the required thermal regime in underground mine workings, the air supplied to the mine is heated using air handling systems. In future, the thermodynamic state of the prepared air flow when it is lowered along the mine shaft changes due to the influence of a number of factors. At the same time, the processes of heat and mass exchange between the incoming air and its environment are of particular interest. These processes directly depend on the initial parameters of the heated air, the downcast shaft depth and the presence of water flows into the mine shaft. Based on the obtained experimental data and theoretical studies, the analysis of the influence of various heat and mass transfer factors on the formation of microclimatic parameters of air in the downcast shafts of the Norilsk industrial district mines is carried out. It is shown that in the presence of external water flows from the flooded rocks behind the shaft lining, the microclimatic parameters of the air in the shaft are determined by the heat transfer from the incoming air flow to the underground water flowing down the downcast shaft lining. The research results made it possible to describe and explain the effect of lowering the air temperature entering the underground workings of deep mines
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Date submitted2020-06-12
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Date accepted2020-06-15
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Date published2020-12-29
Analysis of project organization specifics in small-scale LNG production
- Authors:
- Pavel S. Tcvetkov
- S. V. Fedoseev
Gas industry plays an important role in the global energy sector, and in the coming decades amountsof natural gas production will only increase. One of the fastest growing trends in gas industry is the production of liquefiednatural gas (LNG), which is associated with the necessity to organize flexible systems of gas supply to the regions,remote from gas extraction sites. Industrial structure of LNG production includes projects, belonging to several different groups depending to their scale, in particular, small-scale production (SSLNG), cumulative production capacityof which is approximately 10 % from the industry-wide one. Economic aspects of implementing such projects remainunderexplored, which does not allow to draw objective conclusions regarding the prospects of their implementationin particular regions.This paper contains a review of publications, devoted to SSLNG project studies, aimed at identifying specifics oftheir organization compared to projects of greater scale. The results demonstrate that the majority of internationalcompanies classify projects as SSLNG, if their annual production capacity is below 0.5 million tonnes per annum.Specific capital costs, as well as implementation timelines of such projects, are several times lower than those of projects with greater production capacity, which reduces their risks and minimizes barriers to market entry. Furthermore,SSLNG is the most decentralized subsector in gas industry, aiming to cover the market due to a growing numberof projects, not their specific production capacity. These specific features define significant prospects of SSLNGdevelopment in Russia, both in the context of energy supply to remote regions and diversification of export deliveries.
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Date submitted2020-05-26
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Date accepted2020-09-23
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Date published2020-12-29
Automated ventilation control in mines. Challenges, state of the art, areas for improvement
The article is divided into three main parts. The first part provides an overview of the existing literature on theoretical methods for calculating the optimal air distribution in mines according to the criteria of energy efficiency and providing all sections of mines with the required amount of air. It is shown that by the current moment there are many different formulations of the problem of searching the optimal air distribution, many different approaches and methods for optimizing air distribution have been developed. The case of a single (main) fan is most fully investigated, while for many fans a number of issues still remain unresolved. The second part is devoted to the review of existing methods and examples of the automated mine ventilation control systems implementation in Russia and abroad. Two of the most well-known concepts for the development of such systems are automated ventilation control systems (AVCS) in Russia and the CIS countries and Ventilation on demand (VOD) abroad. The main strategies of ventilation management in the framework of the AVCS and VOD concepts are described and also the key differences between them are shown. One of the key differences between AVCS and VOD today is the automatic determination of the operation parameters of fan units and ventilation doors using the optimal control algorithm, which is an integral part of the AVCS. The third part of the article describes the optimal control algorithm developed by the team of the Mining Institute of the Ural Branch of the Russian Academy of Sciences with the participation of the authors of the article. In this algorithm, the search for optimal air distribution is carried out by the system in a fully automated mode in real time using algorithms programmed into the microcontrollers of fans and ventilation doors. Minimization of energy consumption is achieved due to the most efficient selection of the fan speed and the rate of ventilation doors opening and also due to the air distribution shift control and the partial air recirculation systems introduction. It is noted that currently the available literature poorly covers the issue related to emergency operation modes ventilation systems of mines and also with the adaptation of automated control systems to different mining methods. According to the authors, further development of automated ventilation control systems should be carried out, in particular, in these two areas.
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Date submitted2020-03-20
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Date accepted2020-05-24
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Date published2020-06-30
Landscape monitoring studies of the North Caucasian geochemical province
The data on the geochemical features of the bedrocks and soils of the province are given. Considerable attention is paid to regional abundances, as well as enrichment and dispersion factors of the chemical elements in landscapes. Using the example of the North Caucasus, it is shown that for such indicators as phytomass, geological, geomorphological, and geobotanical features, it is possible to make a preliminary outlining of regional structures corresponding to geochemical provinces. At the same time, a subsequent geochemical study of these structures remains mandatory. Upon determining certain geochemical associations, geochemical provinces can be basically distinguished; to a large extent, geochemical properties of these accumulated and scattered associations of elements contribute to the regional soil geochemistry. The results of long-term monitoring studies of the North Caucasus geochemical province have shown that the key features of the regional landscapes are due to the composition of bedrock and the presence of a large number of ore deposits and occurrences. The data obtained are the basis for assessing the state of the environment in conditions of increasing anthropogenic impact, and the established regional abundances can be used to assess the degree of pollution in agricultural, residential, and mining landscapes.
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Date submitted2016-09-23
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Date accepted2016-11-07
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Date published2017-02-22
Development of energy-saving technologies providing comfortable microclimate conditions for mining
The paper contains analysis of natural and technogenic factors influencing properties of mine atmosphere, defining level of mining safety and probability of emergencies. Main trends in development of energy-saving technologies providing comfortable microclimate conditions are highlighted. A complex of methods and mathematical models has been developed to carry out aerologic and thermophysical calculations. Main ways of improvement for existing calculation methods of stationary and non-stationary air distribution have been defined: use of ejection draught sources to organize recirculation ventilation; accounting of depression losses at working intersections; inertance impact of air streams and mined-out spaces for modeling transitory emergency scenarios. Based on the calculation algorithm of airflow rate distribution in the mine network, processing method has been developed for the results of air-depressive surveys under conditions of data shortage. Processes of dust transfer have been modeled in view of its coagulation and settlement, as well as interaction with water drops in case of wet dust prevention. A method to calculate intensity of water evaporation and condensation has been suggested, which allows to forecast time, duration and quantity of precipitation and its migration inside the mine during winter season.
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Date submitted2015-12-10
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Date accepted2016-02-18
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Date published2016-12-23
Engineering and technical measures to improve reliability of power supply to construction facilities
- Authors:
- P. S. Orlov
The paper examines an issue of ensuring reliable power supply to construction facilities, proposes ways to reduce losses in distribution networks and improve power supply reliability. The primary focus is on increasing the transmission capability of power distribution networks and improving power supply reliability and safety of single-phase electricity consumers. Engineering and technical proposal belongs to the field of electrical engineering and in particular concerns power supply to single-phase consumers from three-phase networks, including construction industry consumers, and can be used in three-phase three-, four- and five-wives alternating current power distribution networks.
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Date submitted2010-07-06
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Date accepted2010-09-06
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Date published2011-03-21
Distribution of products of destruction of granite files
The article considers the problem of size distribution of grain-size composition of the blasted rock mass, rock fragments blasted rock mass and rock blockiness. The logarithmic-normal distribution law is laid down for all blasted granite mass products. It was proved, that logarithmic variance of logarithmic normal distribution law of the fractured rock mass fragments’ distribution is a structural invariant on the level of statistical universe of the block and fragments.
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Date submitted2009-10-26
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Date accepted2009-12-27
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Date published2010-09-22
Support of geodynamic safety in mining of the Khibini deposits
The paper deals with the problems of geodynamics in mining of the Khibini deposits. Description is given to the complex of organizational-technical arrangements for provision of geodynamic safety at the Apatit Co and to principal trends of its development.
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Date submitted2008-10-06
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Date accepted2008-12-10
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Date published2009-12-11
Appearance of entropy principle in distribution оf the gold mass while formation of minable gold mineralization
- Authors:
- S. V. Sendek
The rule of the entropy distributiveness for mass of the metal in gold ores is detected at different scale levels. This regularity is resulted as a consequence of redistribution of the gold and host rocks after their primary conditions. Revealing of those rules may allow reviewing the notions on nature and genesis of gold mineralizaition.
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Date submitted2008-10-17
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Date accepted2008-12-07
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Date published2009-12-11
Morphometry of aggregates and modeling of phase transition kinetics under metamorphism
- Authors:
- Yu. L. Gulbin
The paper discusses some general relations between the structure of metamorphic rocks and mechanisms of phase reactions. Among these relations is the influence of nucleation and growth of kinetics on the crystal size distribution. A brief overview is made of theoretical models which have been proposed to explain granulometric properties of rocks, and kinetic laws and factors on the metamorphic crystallization are considered by the example of metapelitic garnets, including the phenomenon of avalanche nucleation at finite overheating as well as the growth of porphyroblasts under diffusion-limited conditions. As a result, a new approach to modeling of native granulometric curves is presented.