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Date submitted2023-10-29
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Date accepted2024-04-08
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Date published2025-02-25
Evaluation of the impact of the distance determination function on the results of optimization of the geographical placement of renewable energy sources-based generation using a metaheuristic algorithm
- Authors:
- Andrei M. Bramm
- Stanislav A. Eroshenko
Since the United Power System was created electrical supply of remote and hard-to-reach areas remains one of the topical issues for the power industry of Russia. Nowadays, usage of various renewable energy sources to supply electricity at remote areas has become feasible alternative to usage of diesel-based generation. It becomes more suitable with world decarbonization trends, the doctrine of energy security of Russia directives, and equipment cost decreasing for renewable energy sources-based power plants construction. Geological exploration is usually conducted at remote territories, where the centralized electrical supply can not be realized. Placement of large capacity renewable energy sources-based generation at the areas of geological expeditions looks perspective due to development of industrial clusters and residential consumers of electrical energy at those territories later on. Various metaheuristic methods are used to solve the task of optimal renewable energy sources-based generation geographical placement. The efficiency of metaheuristics depends on proper tuning of that methods hyperparameters, and high quality of big amount of meteorological and climatic data. The research of the effects of the calculation methods defining distance between agents of the algorithm on the optimization of renewable generation placement results is presented in this article. Two methods were studied: Euclidean distance and haversine distance. There were two cases considered to evaluate the effects of distance calculation method change. The first one was for a photovoltaic power plant with installed capacity of 45 MW placement at the Vagaiskii district of the Tyumen region. The second one was for a wind power plant with installed capacity of 25 MW at the Tungokochenskii district of the Trans-Baikal territory. The obtained results show low effects of distance calculation method change at average but the importance of its proper choose in case of wind power optimal placement, especially for local optima’s identification.
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Date submitted2024-04-11
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Date accepted2024-11-07
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Date published2025-04-25
Thyristor booster device for voltage fluctuation reduction in power supply systems of ore mining enterprises
The article is devoted to solving the problem of voltage fluctuations in the power supply systems of ore mining enterprises. The connection of high-power consumers with abruptly variable operating mode (for example, high-voltage mining excavators) causes voltage fluctuations and sags, disabling electrical equipment, communication, and automation devices in the 6-10 kV distribution network, which disrupts technological processes, etc. The use of existing solutions and methods to reduce voltage variations caused by dynamic loads is not effective. To solve the problem, booster transformers with high-speed thyristor switches can be used to work out switching the control steps towards increasing or decreasing the voltage. The authors offer a new circuitry solution for a thyristor booster device (TBD) with a pulse-phase control method. The purpose of the research is to determine the control laws of TBD, which enable to effectively reduce voltage fluctuations from dynamic load in the power supply systems of mining enterprises. The article provides a schematic diagram of the TBD and describes the principle of operation of the device. Some modes of increasing and decreasing the output voltage of the TBD, as well as the basic mode (without voltage addition) are provided. Mathematical modeling of TBD control processes was carried out and adjustment characteristics were set taking into account the load power factor. On a simulation computer model of a 6 kV electric network with a dynamic load, the verification of the adjustment characteristics of TBD obtained during mathematical modeling was carried out. Based on the research results, the laws for regulating the output voltage of TBD were established. The TBD effective control range with normal permissible limits of odd harmonics have been determined. The conducted research will make it possible to implement the device control system.
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Date submitted2024-05-03
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Date accepted2024-10-14
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Date published2024-11-12
Genetic geological model of diamond-bearing fluid magmatic system
The article proposes a genetic geological model of diamond deposit formation associated with kimberlites and lamproites. It is based on the synthesis of published data on diamond-bearing kimberlite systems and an original study of the ontogenetic features of diamond crystals. Deep diamond crystallization, its upward transportation and subsequent concentration in near-surface kimberlite-lamproite bodies and other rocks, including those brought to the surface by high-amplitude uplifts of crystalline basement rocks, are combined in a single system. An assumption is made about the primary sources of the Anabar placer diamonds. The possibility of hydrocarbon generation at mantle levels corresponding to diamond formation areas and their transportation to the upper crustal zones by a mechanism similar to the mantle-crust migration of diamond-bearing fluidized magmas is shown. The high rate of their upward movement allows transportation to the surface without significant loss as a result of dissolution in melts and sorption on the surface of mineral phases. The significant role of fluid dynamics at all stages of this system is noted.
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Date submitted2022-03-01
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Date accepted2024-06-03
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Date published2024-12-25
Study of the possibility of using high mineralization water for hydraulic fracturing
The results of laboratory studies aimed at developing hydraulic fracturing fluid based on alternative sources of high mineralization water are presented. It is shown that Cenomanian sources have the most stable mineralization parameters, while bottom water and mixed waters collected from pressure maintenance systems differ significantly in their properties, with iron content varying several times, and hardness and mineralization undergoing substantial changes. The quality of the examined hydraulic fracturing fluids based on alternative water sources is confirmed by their impact on residual permeability, as well as residual proppant pack conductivity and permeability. The experimental results show similar values for these parameters. The comprehensive laboratory studies confirm the potential for industrial use of high mineralization water in hydraulic fracturing operations.
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Date submitted2023-11-10
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Date accepted2024-06-03
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Date published2025-02-25
Enhancing the interpretability of electricity consumption forecasting models for mining enterprises using SHapley Additive exPlanations
- Authors:
- Pavel V. Matrenin
- Alina I. Stepanova
The objective of this study is to enhance user trust in electricity consumption forecasting systems for mining enterprises by applying explainable artificial intelligence methods that provide not only forecasts but also their justifications. The research object comprises a complex of mines and ore processing plants of a company purchasing electricity on the wholesale electricity and power market. Hourly electricity consumption data for two years, schedules of planned repairs and equipment shutdowns, and meteorological data were utilized. Ensemble decision trees were applied for time series forecasting, and an analysis of the impact of various factors on forecasting accuracy was conducted. An algorithm for interpreting forecast results using the SHapley Additive exPlanation method was proposed. The mean absolute percentage error was 7.84 % with consideration of meteorological factors, 7.41 % with consideration of meteorological factors and a load plan formulated by an expert, and the expert's forecast error was 9.85 %. The results indicate that the increased accuracy of electricity consumption forecasting, considering additional factors, further improves when combining machine learning methods with expert evaluation. The development of such a system is only feasible using explainable artificial intelligence models.
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Date submitted2024-06-12
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Date accepted2024-07-18
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Date published2025-04-25
Development of parameters for an industry-specific methodology for calculating the electric energy storage system for gas industry facilities
- Authors:
- Ivan S. Tokarev
The issue of determining the main parameters of electric energy storage systems – power and energy intensity – is being considered, the determination of which is a fundamentally important task when introducing such devices into the power supply systems of enterprises for both technical (technological) and economic reasons. The work analyzes problems that can be solved by installing electricity storage systems at gas industry facilities. An industry-wide methodology has been developed for calculating the parameters of an electricity storage system based on traditional methods and methods aimed at minimizing the standardized cost of electricity with adaptation to the conditions of the gas industry. A distinctive feature of the presented methodology is the ability to determine the power and energy intensity of electricity storage systems when performing several functions. The methodology was tested at a typical gas industry facility – the Yarynskaya compressor station of OOO Gazprom Transgaz Ukhta, a characteristic feature of which is an autonomous power supply system. An example is given of calculating the electricity storage normalized cost using an improved LCOS indicator, which takes into account the effect of changing the fill factor of the electrical load schedule on the amount of gas consumption by a power plant for its own needs. To confirm the economic efficiency of introducing electricity storage systems calculated using the above methodology, calculations of the integral effect, net present value and efficiency index are presented.
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Date submitted2023-06-21
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Date accepted2023-12-27
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Date published2024-12-25
Peculiarities of formation, isomorphism and geochemistry of trace elements of sphalerite and wurtzite unusual varieties from the Goniatite occurrence (Pai-Khoi Ridge, Nenets Autonomous District)
A unique Mn-, Cd-bearing sphalerite from quartz-calcite veins in the coal-bearing series (Visean C1v) marine sediments in a 50 km segment of the middle course of the Silova-Yakha River in the Arctic zone of the European part of Russia (Pai-Khoi Ridge) has been studied. The veins have a conformable and cross-cutting occurrence in two types of rocks: gray limestones and black siliceous-carbonaceous shales, the area is known as the Goniatite occurrence. The sulfide content in vein samples ranges from 0.1 to 2 vol.%. The chemical composition of 27 monomineral samples of Mn-, Cd-bearing sphalerites was studied, 82 points were analyzed. Correlations between typomorphic elements-impurities were revealed and correlation matrix was constructed. Cu, V, Ga, In, Sn, As, Sb, Bi, Pb, Tl, Se, Ag, Au, Ni are positively correlated with each other; Cd, Mn and Ge are negatively correlated with each other. The hydrothermal fluid involved in crystallization of sphalerite is characterized by low temperature (164-211 °С) and average salinity of 5-6 wt.% eq. NaCl. An updated “portrait” of typomorphic features (composition and properties) of sphalerite of the Pai-Khoi province was obtained. The features allowing to determine the type of impurity entering the sphalerite structure – in the form of isomorphic impurity or in the form of microinclusions of paragenetic association minerals – have been established. Submicron inclusions of sulvanite and colusite, invisible by other methods, were detected in sphalerite (by LA-ICP-MS method).The cathodoluminescence data of sphalerite from the Pai-Khoi province were typified. In contrast to other provinces, ZnS crystals here are characterized by almost complete absence of isomorphic iron. This allowed us to study pure isomorphism schemes of ZnS↔MnS, ZnS↔CdS, namely cathodoluminescence and other types of luminescence. The presence of a rare wurtzite-4H polytype in assemblage with sphalerite was revealed. High contents of strategic metals Cd, Ga, In, Ge in the ZnS matrix, as well as sulvanite (V, Cu) in a single paragenesis were found. A serious reassessment of the potential for industrial use of this mineralization will be required.
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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 submitted2021-05-08
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Date accepted2022-07-21
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Date published2023-12-25
Technologies of intensive development of potash seams by longwall faces at great depths: current problems, areas of improvement
- Authors:
- Vladimir P. Zubov
- Denis G. Sokol
The results of the analysis of practical experience in the development of potash seams using longwall mining systems at the mines of OAO “Belaruskali” are presented. Positive changes in the technical and economic indicators of mines and an increase in the safety of mining operations were noted with the introduction of resource-saving technologies without leaving the pillars between the excavation columns or with leaving the pillars between the columns with dimensions at which they are destroyed by mining pressure in the goaf. It is noted that the use of mechanized stoping complexes characterized by high energy capacity, combined with large depths of development, is the main reason for the temperature increase in longwalls to values exceeding the maximum permissible air temperature regulated by sanitary standards. Based on production studies, it was concluded that the temperature regime along the length of the longwall face is determined by the temperature of rocks in the developed longwall space, heat emissions from the equipment of the power train, and the temperature of the rock mass ahead of the longwall. The conclusion has been drawn about the feasibility of using developed technological schemes in deep mining conditions, which provide a reduction in longwall temperature by 6-9 °C or more through isolated ventilation of longwall and power trains, as well as heat exchange between the airflow entering the longwall and the rocks in the developed space.
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Date submitted2022-11-29
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Date accepted2023-03-02
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Date published2023-10-27
New data on the composition of growth medium of fibrous diamonds from the placers of the Western Urals
This article presents the results of studying microinclusions of fluids/melts in diamonds from the placers of the Krasnovishersky District (western slope of the Middle/Northern Urals), which make it possible to establish the evolution of diamond-forming media in the subcontinental lithospheric mantle of the eastern margin of the East European craton. Impurity composition of the studied crystals reveals three different types of diamonds, the formation of which was associated with separated metasomatic events. Microinclusions in B-type diamonds containing A and B nitrogen defects reflect an older metasomatic stage characterized by the leading role of silicic and low-Mg carbonatitic fluids/melts. The second stage is associated with the growth of A-type diamonds containing nitrogen exclusively in the form of A-centers. At this stage, the formation of diamonds was related with low-Mg carbonatitic media, more enriched in MgO, CaO, CO2, and Na2O compared to B-type diamonds. The third stage probably preceded the eruption of the transporting mantle melt and led to the formation of C-type diamond containing A and C nitrogen defect centers and microinclusions of silicic to low-Mg carbonatitic composition. The recorded trend in the evolution of diamond-forming fluids/melts is directed towards more carbonatitic compositions. Fluids/melts are probably sourced from eclogitic and pyroxenitic mantle substrates.
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Date submitted2023-07-19
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Date accepted2023-07-19
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Date published2023-07-19
Energy efficiency in the mineral resources and raw materials complex
Energy efficiency and energy saving at all times and especially at the present stage of development of industry and economy have played an extremely important role. Regardless of which countries and according to what criteria they build energy development plans, energy efficiency and energy saving are always a priority. This fully applies to the mineral resources complex, in which energy consumption as a whole makes up a large share of total consumption. The resources mined in the mineral resources complex are themselves a source of energy. The energy sector is evolving in many ways. Many scientific works, the results of which are reflected in publications, confirm the relevance of research in the energy efficiency field. But the approach to individual decisions in the mineral resource industry is specific and it is worth of separate consideration. Recently, much attention has been paid to “green energy” and renewable energy sources. However, energy efficiency in the field of traditional generation and consumption remains an urgent problem and its solution is in constant development. One of the main directions for improving energy efficiency is the development of autonomous systems for the electrical and thermal power engineering. All these problems are reflected in a special volume of the Journal of the Mining Institute, the articles are divided into four sections: energy efficiency of the electric drive in the mineral resources complex (MRC); energy efficiency of industrial plants and enterprises in MRC; power quality and renewable sources in MRC; autonomous power supply systems in MRC. The presented articles contain valuable material from the scientific and practical points of view and can form the basis for further research in the energy efficiency field.
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Date submitted2023-03-14
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Date accepted2023-06-20
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Date published2023-07-19
Forecasting planned electricity consumption for the united power system using machine learning
The paper presents the results of studies of the predictive models development based on retrospective data on planned electricity consumption in the region with a significant share of enterprises in the mineral resource complex. Since the energy intensity of the industry remains quite high, the task of rationalizing the consumption of electricity is relevant. One of the ways to improve control accuracy when planning energy costs is to forecast electrical loads. Despite the large number of scientific papers on the topic of electricity consumption forecasting, this problem remains relevant due to the changing requirements of the wholesale electricity and power market to the accuracy of forecasts. Therefore, the purpose of this study is to support management decisions in the process of planning the volume of electricity consumption. To realize this, it is necessary to create a predictive model and determine the prospective power consumption of the power system. For this purpose, the collection and analysis of initial data, their preprocessing, selection of features, creation of models, and their optimization were carried out. The created models are based on historical data on planned power consumption, power system performance (frequency), as well as meteorological data. The research methods were: ensemble methods of machine learning (random forest, gradient boosting algorithms, such as XGBoost and CatBoost) and a long short-term memory recurrent neural network model (LSTM). The models obtained as a result of the conducted studies allow creating short-term forecasts of power consumption with a fairly high precision (for a period from one day to a week). The use of models based on gradient boosting algorithms and neural network models made it possible to obtain a forecast with an error of less than 1 %, which makes it possible to recommend the models described in the paper for use in forecasting the planned electricity power consumption of united power systems.
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Date submitted2023-03-16
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Date accepted2023-06-20
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Date published2023-07-19
Evaluation of the influence of the hydraulic fluid temperature on power loss of the mining hydraulic excavator
In the steady state of operation, the temperature of a mining excavator hydraulic fluid is determined by the ambient temperature, hydraulic system design, and power losses. The amount of the hydraulic system power loss depends on the hydraulic fluid physical and thermodynamic properties and the degree of wear of the mining excavator hydraulic system working elements. The main causes of power losses are pressure losses in pipelines, valves and fittings, and leaks in pumps and hydraulic motors. With an increase in the temperature of hydraulic fluid, its viscosity decreases, which leads, on the one hand, to a decrease in power losses due to pressure losses in pipelines, valves and fittings, and, on the other hand, to an increase in volumetric leaks and associated power losses. To numerically determine the level of power losses occurring in the hydraulic system on an example of the Komatsu PC750-7 mining excavator when using Shell Tellus S2 V 22, 32, 46, 68 hydraulic oils with the corresponding kinematic viscosity of 22, 32, 46, 68 cSt at 40 °C, the developed calculation technique and software algorithm in the MatLab Simulink environment was used. The power loss coefficient, obtained by comparing power losses at the optimum temperature for a given hydraulic system in the conditions under consideration with the actual ones is proposed. The use of the coefficient will make it possible to reasonably select hydraulic fluids and set the values of the main pumps limit state and other hydraulic system elements, and evaluate the actual energy efficiency of the mining hydraulic excavator. Calculations have shown that the implementation of measures that ensure operation in the interval with a deviation of 10 % from the optimal temperature value for these conditions makes it possible to reduce energy losses from 3 to 12 %.
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Date submitted2023-03-02
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Date accepted2023-06-20
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Date published2023-07-19
Improving the efficiency of autonomous electrical complex with renewable energy sources by means of adaptive regulation of its operating modes
Renewable energy sources are gradually becoming useful in mining industry. They are actively used in remote, sparsely populated areas to power shift settlements, geological and meteorological stations, pipeline equipment, mobile cell towers, helicopter pads lighting, etc. In comparison with diesel generators, systems with renewable sources do not require fuel transportation, have short payback periods and flexible configuration for different categories of electrical loads. The main obstacles to their spread are instability of generation and high cost of produced electricity. One of the possible ways to solve these problems is to develop new technologies, increase power density of generators and energy storage systems. The other way represents energy saving and rational use of affordable resources. The new solutions for implementation of the second method are proposed in this work. The object of the study is autonomous DC electrical complex with photovoltaic and wind power sources. In such systems the generated power from renewable sources is transferred to consumers via intermediate DC bus, the voltage level of which affects the power losses in the process of power transmission. The vast majority of complexes have a problem that their DC bus voltage is constant, while the optimum voltage level with lowest losses varies depending on the generated and consumed power. Therefore, electrical complexes potentially lose a part of the transmitted energy. To avoid this, a special algorithm was added to automatically adjust DC bus voltage to optimum level according to changes in working conditions. An additional contribution to efficiency improvement can be made by dynamic change of operating frequency in power converters depending on their load. The evaluation based on results of computer simulation showed that in a complex with rated power 10 kW active power losses during its lifetime can be reduced by 2-5 %.
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Date submitted2023-03-12
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Date accepted2023-06-20
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Date published2023-07-19
Increasing the energy efficiency of an autonomous power supply system of a drilling rig in case of voltage dips
The article discusses the emergency modes of operation of an autonomous electrical complex of a drilling rig. The concept of voltage failure and its influence on the technological process of industrial enterprises is revealed. A description of the methods used in the power supply of industrial enterprises to overcome voltage dips and load surges in autonomous power systems is presented, from which it is possible to single out the accelerated lifting of critical equipment to prevent emergency conditions, as well as the use of backup storage, usually batteries. An algorithm has been developed for the interaction of the battery and the diesel generator set as backup power sources during various modes of operation of the electric motor, taking into account load surges, which allows successfully overcoming voltage dips in the system both in transient and in steady state. It is proposed to use a combined method to eliminate the voltage dip, a feature of which is the use of a combined structure of backup power sources as part of a diesel generator set and a battery, acting on the base of the proposed interaction algorithm in autonomous electrical complexes. The method makes it possible to overcome sudden load surges and voltage dips caused by a shortage of reserve power in the electrical system. The use of a rechargeable battery as a transitional element makes it possible to switch between the main and backup power sources without stopping the technological one and to expand the overload threshold of an autonomous electrical complex up to 60 %. The use of the combined method increases the energy efficiency of the autonomous complex due to a reduction in the number of emergency shutdowns of equipment, process interruptions and additional power consumption.
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Date submitted2022-10-26
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Date accepted2023-02-13
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Date published2023-07-19
Determination of the grid impedance in power consumption modes with harmonics
The paper investigates the harmonic impedance determination of the power supply system of a mining enterprise. This parameter is important when calculating modes with voltage distortions, since the determined parameters of harmonic currents and voltages significantly depend on its value, which allow the most accurate modeling of processes in the presence of distortions in voltage and current. The power supply system of subsurface mining is considered, which is characterized by a significant branching of the electrical network and the presence of powerful nonlinear loads leading to a decrease in the power quality at a production site. The modernization of the mining process, the integration of automated electrical drive systems, renewable energy sources, energy-saving technologies lead to an increase in the energy efficiency of production, but also to a decrease in the power quality, in particular, to an increase in the level of voltage harmonics. The problem of determining the grid harmonic impedance is solved in order to improve the quality of design and operation of power supply systems for mining enterprises, taking into account the peculiarities of their workload in the extraction of solid minerals by underground method. The paper considers the possibility of determining the grid impedance based on the measurement of non-characteristic harmonics generated by a special nonlinear load. A thyristor power controller based on phase regulation of the output voltage is considered as such a load. Simulation computer modeling and experimental studies on a laboratory test bench are used to confirm the proposed method. The recommendations for selecting load parameters and measuring device connection nodes have been developed.
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Date submitted2022-08-10
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Date accepted2023-02-28
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Date published2024-02-29
Selection of the required number of circulating subs in a special assembly and investigation of their performance during drilling of radial branching channels by sectional positive displacement motors
The task of sludge removal to the surface during construction of directional and horizontal wells and strongly curved radial channels is relevant. For stable operation of technical system “Perfobore”, it is proposed to use a circulating sub that ensures efficient cleaning of channel wellbore from the drilled rock. Two schemes of technical system “Perfobore” are considered, consisting of two seven-meter coiled tubing, a positive displacement motor, a bit and one circulating sub in the first scheme and two subs in the second scheme. For each of the schemes CFD modeling was implemented to determine values of pressure and speed. It was found out that the use of two circulating subs in the assembly is more efficient. In order to confirm the numerical experiment, bench tests were carried out. It was determined that the designed circulating sub can eject up to 25 % of pumped drilling fluid. The bench tests of full-size technical system “Perfobore” for drilling 14-meter channels with two circulating subs showed that the axial load on positive displacement motor produced by hydraulic loader was 3000 N and pressure drop depending on flow rate was 1.5-2.0 MPa. This allows the motor to operate at maximum power.
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Date submitted2022-08-05
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Date accepted2022-11-17
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Date published2023-02-27
Feasibility study of using cogeneration plants at Kuzbass coal mines
The paper considers the problem of reducing greenhouse gas emissions in the process of coal mining during the coal mine methane utilization in power supply systems. An algorithm to form recommendations for the implementation of CMM generation is presented. A simulation model for one of the Kuzbass coal mines was developed in the PowerFactory software application. The simulation model considers the uneven nature of the power consumption of mining equipment. As a result of modeling, daily power consumption profiles and voltage levels in the coal mine power supply system were determined before and after the implementation of the proposed measures. Based on the results, the technical and economic effects was estimated, which consisted in reducing the direct and indirect carbon footprint, electricity and capacity fees. It has been established that the cost of carbon dioxide emission quotas significantly affects the investment attractiveness of cogeneration projects. Based on the results, recommendations are given to stimulate the development of small generation in coal mines.
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Date submitted2022-03-24
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Date accepted2022-07-21
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Date published2022-12-29
A probabilistic study on hole cleaning optimization
- Authors:
- Seyyed Shahab Tabatabaee Moradi
Hole cleaning is considered as one of the most important drilling fluid functions. An efficient hole cleaning ensures a reliable well drilling practice with minimum troublesome problems. In this study, two main steps of hole cleaning, i.e., cuttings removal from under the bit and cuttings transport to the surface are discussed based on the drilling data of a shale formation. The traditional models for optimization of each step are presented. As the models require variety of input data, which are usually subjected to some extent of errors and uncertainties, the output of the model is also an uncertain parameter. Using Monte Carlo simulation, a simple probabilistic study was conducted to quantify the certainty level of the obtained results. Based on the result of this study, it is shown that for the proposed well, a good hole cleaning is expected. However, a more reliable decision for further hole cleaning optimization should be made considering the results of uncertainty analysis.
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Date submitted2022-03-01
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Date accepted2022-05-25
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Date published2022-12-29
Study on the rheological properties of barite-free drilling mud with high density
Improved drilling and reservoir penetration efficiency is directly related to the quality of the drilling mud used. The right choice of mud type and its components will preserve formation productivity, stability of the well walls and reduce the probability of other complications. Oil and gas operators use barite, less often siderite or hematite weighting agent as a weighting component in the composition of drilling muds for the conditions of increased pressure. But the use of these additives for the penetration of the productive formation leads to the reduction of filtration characteristics of the reservoir, as it is almost impossible to remove them from the pore channels. Therefore, barite-free drilling mud of increased density based on formic acid salts with the addition of carbonate weighting agent as an acid-soluble bridging agent is proposed. The results of experimental investigations on rheological parameters of barite-free solutions are given and the obtained data are analyzed. Based on the comparison of results it is recommended to use high-density drilling mud on the basis of formic acid salts (sodium and potassium formate) and with the addition of partially hydrolyzed polyacrylamide with molecular mass of 27 million.
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Date submitted2022-04-12
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Date accepted2022-11-17
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Date published2022-12-29
Development of technological solutions for reliable killing of wells by temporarily blocking a productive formation under ALRP conditions (on the example of the Cenomanian gas deposits)
Modern field operation conditions are characterized by a decline in gas production due to the depletion of its reserves, a decrease in reservoir pressure, an increase in water cut, as well as due to the depreciation of the operating well stock. These problems are especially specific at the late stage of development of the Cenomanian deposits of Western Siberia fields, where the anomaly factor below 0.2 prevails, while gas-bearing formations are represented mainly by complex reservoirs with high-permeability areas. When killing such wells, the classical reduction of overbalance by reducing the density of the process fluid does not provide the necessary efficiency, which requires the search for new technical and technological solutions. In order to prevent the destruction of the reservoir and preserve its reservoir properties during repair work in wells with abnormally low reservoir pressure, AO “SevKavNIPIgaz” developed compositions of special process fluids. A quantitative description of the process of blocking the bottomhole formation zone is proposed by means of mathematical modeling of injection of a gel-forming solution into a productive horizon. The well killing technology includes three main stages of work: leveling the injectivity profile of the productive strata using three-phase foam, pumping the blocking composition and its displacement with the creation of a calculated repression. Solutions obtained on the basis of a mathematical model allow optimizing technological parameters to minimize negative consequences in the well killing process.
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Date submitted2022-05-12
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Date accepted2022-09-15
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Date published2022-12-29
Problem solution analysis on finding the velocity distribution for laminar flow of a non-linear viscous flushing fluid in the annular space of a well
- Authors:
- Vasiliy I. Nikitin
Modern drilling fluids are non-linear viscous media with an initial shear stress. In classical scientific works on hydromechanical modeling of drilling fluids motion in pipes and annular channels the Shvedov – Bingham approximation and Ostwald – de Waale power-law model were used, which did not fully account for behavior of technological fluids in a wide range of shear rates. This article presents a numerical solution for a mathematical model of drilling fluid motion of the three-parameter Herschel – Bulkley rheological model in the annular space of the well. The Herschel – Bulkley model in the rheological equation takes into account the presence of initial shear stress and a tendency for viscosity to change with shear rate, which distinguishes it from the Ostwald – de Waale and Shvedov – Bingham models. The target function in solving the equation of motion is the velocity distribution in the radial direction of the upward flow of the flushing fluid. The analysis of obtained solution is based on the theory of velocity profile influence on quality of cuttings removal during wellbore cleaning. Due to peculiarities of mathematical statement of the task, which supposes necessity of differential equation of motion solution, Wolfram Mathematica computational software has been used as a calculation tool. The analysis of numerical solution allowed to draw conclusions about the possibility of its application in evaluation of velocity profile when drilling fluid moves in annular space of the well. The possibility for application of modified excess coefficient as a relative quantitative parameter for evaluation of velocity profile uniformity was substantiated.
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Date submitted2022-02-24
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Date accepted2022-05-25
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Date published2022-07-26
Litsa uranium ore occurrence (Arctic zone of the Fennoscandian Shield): new results of petrophysical and geochemical studies
Mineralogical, petrophysical and geochemical studies have been carried out to determine the sequence and formation conditions of uranium mineralization within the Litsa ore occurrence (Kola Region). Mineralogical studies show the following formation sequence of ore minerals: uraninite – sulfides – uranophane, coffinite, pitchblende. Two stages of uranium mineralization are distinguished: Th-U (1.85-1.75 Ga) and U (400-300 Ma). The distribution of physical properties of rocks in the area is consistent with the presence of two temporal stages in the formation of mineralization with different distribution and form of uranium occurrence in rocks. The factors that reduce rock anisotropy are the processes of migmatization and hydrothermal ore mineralization, which heal pores and cracks. Fluid inclusions in quartz studied by microthermometry and Raman spectroscopy contain gas, gas-liquid and aqueous inclusions of different salinity (1.7-18.4 wt.% NaCl-eq.). According to homogenization temperatures of inclusions in liquid phase, the temperature of the Paleoproterozoic and Paleozoic stages of uranium mineralization at the Litsa ore occurrence is ~ 300 and 200 °С, respectively. Correlations of the spatial distribution of elastic anisotropy index with an elevated radioactive background allow using this petrophysical feature as one of the prognostic criteria for uranium and complex uranium mineralization when carrying out uranium predictive work.
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Date submitted2021-09-16
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Date accepted2022-02-24
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Date published2022-04-29
Production of microfluidic chips from polydimethylsiloxane with a milled channeled surface for modeling oil recovery during porous rock waterflooding
Microfluidic chips with porous structures are used to study the flow of oil-containing emulsion in the rock. Such chips can be made from polydimethylsiloxane by casting into a master mold. At the initial stages of research, fast and cheap prototyping of a large number of different master molds is often required. It is proposed to use milling to make a channeled surface on a polymethyl methacrylate plate, from which a negative image should be taken, which is the master mold for casting positive polydimethylsiloxane chips in it. Several epoxy compositions have been tested to make this master mold. The main requirement in the search for the material was the exact replication of the geometry and sufficiently low adhesion to polymethyl methacrylate and polydimethylsiloxane for removing the product with minimal damage to the mold. It was possible to make master molds from all the materials used, but with defects and various degrees of damage. One of the epoxy compositions was found suitable for making a master mold with many elements simulating the grains of a porous medium (height to width ratio 2:3). The developed method makes it possible to use polydimethylsiloxane for prototyping chips simulating the porous structure of an oil rock.
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Date submitted2021-03-11
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Date accepted2021-04-12
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Date published2022-04-29
Operation mode selection algorithm development of a wind-diesel power plant supply complex
- Authors:
- Yaroslav E. Shklyarskiy
- Daria E. Batueva
The power supply system is affected by external disturbances, so it should be stable and operate normally in compliance with power quality standards. The power supply system goes into abnormal modes operation when, after a short-term failure or disturbance, it does not restore normal mode. The electrical complex, which includes a wind power plant, as well as a battery and a diesel generator connected in parallel, is able to provide reliable power supply to consumers which meets the power quality indicators. The article develops an algorithm that is implemented by an automatic control system to select the operating mode depending on climatic factors (wind) and the forecast of energy consumption for the day ahead. Forecast data is selected based on the choice of the methods, which will have the smallest forecast error. It is concluded that if the energy consumption forecast data is added to the automatic control system, then it will be possible to increase the efficiency of the power supply complex. In the developed algorithm the verification of normal and abnormal modes of operation is considered based on the stability theory. The criteria for assessing the normal mode of operation are identified, as well as the indicators of the object’s load schedules for assessing the load of power supply sources and the quality standards for power supply to consumers for ranking the load by priority under critical operating conditions and restoring normal operation are considered.