Vol 335, No 12 (2024)

Relevance. Plunger units, in particular rod and rodless ones with surface and submerged drive, are widely used in the oil industry for extraction of high-viscosity emulsion from marginal wells. The main advantage of such units is the possibility to operate in conditions of highly viscous emulsions with viscosity values up to 200–300 cPs. However, there are peculiarities of plunger unit operation, which lead to some complications. One of the most widespread complications is high wellhead pressure, which leads to increased dynamic loads on pump and drive units. Qualitative and precise definition of wellhead pressure value depending on well and unit parameters will contribute to more effective design, operation and evaluation of plunger unit reliability. Known studies and methods of wellhead pressure determination have limitations related to single-factor influence of some parameter on wellhead pressure values. This approach is not suitable for taking into account the simultaneous influence of several parameters. Aim. Development of calculation methodology, which allows taking into account complex influence of well operation parameters on wellhead pressure value and dynamic loads on plunger rods. Objects. Fund of wells equipped with borehole rod pump units. Methods. Statistical and regression analysis of the stock of wells equipped with downhole rod pumping units, development of a neural network. Results. A stock of wells equipped with downhole sucker-rod pumps, the technological mode of which is provided by one of the companies of Privolzhsky federal district, was investigated as an example, on the basis of the specified stock the factors influencing the value of wellhead pressure were established and the technique on its forecasting was developed. The authors have proposed the method for discarding the data with a wide range of values when analyzing the factors affecting the wellhead pressure. The method consists in excluding the values of fluid viscosity not lying on the "hump" characteristic of the function "fluid viscosity – watercut". The authors developed the calculation method based on regression dependences and neural network. It allows forecasting more accurately the value of loads on the pump rods.

Relevance. The improvement of the low-temperature properties of diesel fuels is achieved using various methods of dewaxing and isomerization, leading to almost complete loss of n-alkanes and, accordingly, to deterioration in the detonation properties of fuels. Partial dewaxing of diesel fuels is of interest. It allows the preservation of most of the n-alkanes. Objects. Diesel fuel of a weighted fractional composition, the improvement of low-temperature properties of which is carried out by means of its partial dewaxing by centrifugation with the addition of aluminum powder to the fuel. Methods. Initial diesel fuel dewaxing was carried out on a refrigerated centrifuge SL/8R Centrifuge, which provides a rotor rotation speed of up to 9500 rpm in the temperature range from 40 to minus 10°C. At low temperatures, relatively high-melting paraffin components were released as a precipitate in the rotor tubes. The efficiency of the initial diesel fuel dewaxing was evaluated by the dewaxed diesel fuel yield and by its quality indicators – turbidity temperature, refractive index, filterability limit temperature and solidification temperature. The distribution of n-alkanes in the dewaxing products relative to the starting fuel was determined by gas-liquid chromatography. Aim. To increase the efficiency of the diesel fuel dewaxing by centrifugation with the addition of aluminum powder to the raw material as a paraffin weighting agent. Results and conclusions. The authors have determined the optimal parameters of diesel dewaxing to ensure the production of summer diesel fuel of the "C" brand corresponding to EN 590. The maximum yield of dewaxed diesel fuel at optimal process parameters reaches 78.6 wt %. Dewaxed diesel fuel has a turbidity temperature of minus 5°C, its maximum filterability temperature is minus 6°C and the solidification temperature is minus 15°C.

Relevance. The continued dependence on the combustion of carbon-based fuels for energy and industry leads to the need to develop various categories of technologies to reduce carbon dioxide emissions. Aim. Development of carbon capture and storage technologies for all stages of fuel conversion and processing, ensuring a low-carbon cycle for the production of electrical and thermal energy, as well as industrial and social facilities. Methods. Chemical, physical adsorption and absorption. Results and conclusions. For large industrial and energy producers, for small energy consumers, it is necessary to be guided by the principles of environmental friendliness and efficiency when implementing the production process, and to increase the percentage of carbon dioxide removal, implement decarbonization technologies at all stages of producing electricity and thermal energy. For the category of CO₂ removal at the stage of preliminary fuel conversion, adsorbent compositions using predominantly environmentally friendly and inexpensive natural materials based on bentonite have been developed and tested. The collection capacity of the developed adsorbents is 85–98%. For the category of CO₂ removal at the stage of fuel use, a hybrid energy system is presented, including a microgas turbine with heat recovery, a high-temperature fuel cell and other devices and material flows connecting them. A pilot industrial prototype of a 30 kW hybrid energy system will produce heat, electricity, steam, and hot water. In this embodiment, the hybrid system can work as an autonomous energy source for small social and commercial facilities, representing a pilot stage of the engineering and design implementation of the results of an industrial-level hybrid system. For the category of carbon dioxide removal at the stage of CO₂ separation from the flue gas mixture after fuel conversion, a block for removing CO₂ from flue gases using the absorption method was proposed. Solutions of 15% monoethanolamine, 15% ammonia solution, and 6% sodium hydroxide solution showed the best absorption capacity. It is proposed to equip the hybrid energy system with a CO₂ capture unit for complete decarbonization of gas emissions based on closed-cycle technology. The proposed technology for capturing and storing carbon dioxide at the post-fuel conversion stage is characterized by ease of implementation and economic accessibility.

Relevance. The need to enhance oil recovery from horizontal wells under complex geological and technical conditions. The use of more accurate numerical models, including chemical reactions and the modeling of complex fracture systems, allows optimization of well stimulation, significantly improving both economic and technological efficiency. This is particularly important for developing low-permeability reservoirs and operating under challenging conditions. This work examines the numerical modeling of well inflow stimulation methods using various approaches. For acid treatment modeling, approaches based on changes in well productivity and the use of chemical reactions in the hydrodynamic model were applied. The quality of forecasted technological performance was assessed using real data from an analogous well. As a result, in the case of a real field with extended horizontal wells, additional oil production was achieved through different approaches to acid treatment modeling. Multistage hydraulic fracturing was modeled using planar and discrete fracture models, with only minor discrepancies in the hydrodynamic modeling results between these methods. Aim. To assess the effectiveness of various numerical modeling approaches for well inflow stimulation methods, such as acid treatment and aimed at optimizing oil production from extended horizontal wells. Methods. Numerical models were used to evaluate the effectiveness of stimulation methods, focusing on changes in productivity, the impact of chemical reactions, and sensitivity analysis of treatment parameters. Results and conclusions. It was found that the use of negative skin factors significantly increases oil production compared to models accounting for chemical reactions. Sensitivity analysis of acid volume and concentration helped identify optimal parameters for enhancing acid treatment efficiency. Both modeling approaches (planar and discrete fracture systems) yielded comparable results. Multistage hydraulic fracturing demonstrated a 25000-ton increase in oil production over three years, making it a more effective method than acid treatment.

Relevance. The operation of any heating systems is determined by the interrelationship of many physical processes. Recently, for heating large premises, it has been increasingly proposed to use heating systems based on gas infrared heaters of various designs. Such systems are most relevant for large industrial premises, as they are capable of creating favorable living and working conditions in a local work area without significant costs for heating the rest of the premise. When designing complex systems, an important factor is the use of simple relationships to assess the trends of average values ​​of parameters aimed at achieving the desired result. There is a need to set the main dimensionless criteria that determine a particular process within the framework of similarity theory. Aim. To state the basic relationships and dimensionless criteria for analytical engineering assessment of the average temperature over the volume of a premise and the dynamics of its change during heating the premise by a system based on the gas infrared heaters. Objects. Heating system with gas infrared heaters. Methods. Mathematical modeling was carried out within the framework of a 0D mathematical formulation. Results. The authors have stated the main relationships and dimensionless criteria for the analytical assessment of temperature and the dynamics of its change during heating of the premise by a system based on a gas infrared heater on the basis of the approach averaged over the entire volume of the premise. The results of calculations according to the obtained relationships are presented in comparison with the results of calculations according to the full 0D model, which are verified on the results of 2D modeling and experimental measurements.

Relevance. The need to obtain information about the chemical nature of the resin-asphaltene and oil components of atmospheric residue from distillation of crude oil produced at the Krapivinskoe field in order to select optimal technologies for its rational utilization. Aim. To study the structures of asphaltene macromolecules and resin substances and the molecular composition of the oil components of atmospheric residue from distillation of crude oil produced at the Krapivinskoe field. Methods. Transmission electron microscopy, X-ray phase analysis, IR spectroscopy, ¹H NMR spectroscopy, structural group analysis, chemical destruction, gas chromatography-mass spectrometry. Results. The structure of resin-asphaltene substances and the molecular composition of atmospheric residue obtained in the course of atmospheric distillation of oil from the Krapivinskoe field in laboratory conditions have been characterized using a complex of physicochemical research methods. It was found out that asphaltenes of atmospheric residue have a predominantly amorphous structure because of the presence of a developed alkyl chain configuration in their macromolecules. Mean asphaltene molecules consist of three structural blocks, which basis is triarene cores condensed with four to five naphthenic rings. These naphthenoaromatic systems neighbor upon methyl substituents only. The mean molecules of atmospheric residue resins are predominantly single-block. Their structural blocks are more compact due to the smaller number of aromatic and naphthenic rings in the naphthenoaromatic system. A feature of mean resin molecules is also the presence of relatively long alkyl substituents in the blocks. It was established that the structure of asphaltenes and atmospheric residue resins contains fragments linked to each other or to the naphthenoaromatic core of their macromolecules through sulfide and ether bridges. In both types of ‘linked’ fragments, n‑alkanes, n-alkylcyclohexanes and hopanes were identified. Among the fragments linked through sulfide bridges, n‑alkylbenzenes, n-alkylmethylbenzenes and n-alkanoic acids were additionally identified, while ethyl esters of n-alkanoic acids were identified among fragments linked through ether bridges. A structural feature of the atmospheric residue resins is the presence of phenylalkanes with different positions of the phenyl substituent in both types of bridge-linked compounds. Steranes and phenanthrenes are present in the composition of compounds linked through sulfide bridges. The oil components of atmospheric residue contain n-alkanes, n-alkylcyclohexanes, hopanes, steranes, n-alkylbenzenes, n-alkylmethylbenzenes, alkylnaphthalenes and alkylphenanthrenes.

Relevance. The need to improve the efficiency of energy use of fossil fuels and renewable biomass resources through their thermal upgrading. Aim. To establish the relationship between the yield of liquid products of microwave pyrolysis of organic raw materials with different degrees of metamorphism and the process duration. Methods. Certified SS methods for determining the thermal characteristics and elemental composition of the organic and mineral parts of organic raw materials, the “transmission–reflection” method for measuring the imaginary (ε'') and real (ε') components of the complex dielectric constant, physical experiment, gas analysis, high-speed video filming. Results. Based on the analysis of the material balance and duration of the microwave pyrolysis of various types of organic raw materials, the authors have supposed that the destruction of complex organic compounds leads to the formation of carbon particles on the surface of the sample. These particles have high electrically conductive properties relative to the original raw materials. In the presence of a large number of such particles in the microwave field, interparticle electrical discharges can occur, spreading along the sample, resulting in an increase in the heating rate. For raw materials with a higher yield of liquid products, the number of carbon particles also increases. This leads to an increase in the number of discharges between such centers and a proportionate acceleration of material heating. It was experimentally shown and theoretically substantiated that the duration of the microwave pyrolysis of organic raw materials directly depends on material heating rate: due to an increase in the yield of liquid products and a subsequent increase in the concentration of carbon centers, the duration of the microwave pyrolysis process decreases. The results obtained can be used to evaluate the efficiency of microwave pyrolysis of organic raw materials or fuel compositions consisting of materials with different yields of liquid products.

Relevance. The tectonic factor affects the hydrogeological conditions. To assess the tectonics impact on hydrogeological conditions, it is necessary to use an integrated approach. The article considers the hydrogeochemical features of groundwater formed in the area of Lake Glubokoe in the Moscow region, confined to the so-called Trostenskaya depression. Aim. To identify the isotope-chemical characteristics of groundwater due to the effect of the latest tectonic structure of the area. Methods. The chemical composition of natural waters was monitored using ion chromatography on a high-performance ion liquid chromatograph LC-20 and inductively coupled plasma mass spectrometry on an Agilent 7700 x spectrometer. The contents of stable isotopes of oxygen (δ¹⁷O and δ¹⁸O) and hydrogen (δD) were determined by laser light attenuation spectroscopy with an annular multi-pass cuvette on a Picarro L2140i analyzer. Results and conclusions. The groundwater of the Podolsk-Myachkovsky aquifer complex in the area of development of the Trostenskaya depression is characterized by increased mineralization, as well as a higher content of bicarbonates and calcium, compared to groundwater common in the peripheral parts of the research area. Higher concentrations of micro-components (strontium, barium, scandium, rubidium, etc.) were recorded within the studied structure. Groundwater characterized by a heavier isotopic composition (δ¹⁸O, δD, δ¹⁷O) is also confined to the Trostenskaya depression. Data on the ratio of δ¹⁸O, δ²H and δ¹⁷O in natural waters were obtained for the first time for the studied area. It is likely that groundwater in the central and northwestern parts of the study area has a heavier formed isotopic composition due to the inflow of water in the postglacial period.

Relevance. The need for accurate forecasting of electricity consumption to improve efficiency and reduce costs at industrial enterprises, which leads to increased competitiveness of goods manufactured by the enterprise. Traditional forecasting methods often do not take into account complex interactions between various factors affecting energy consumption and do not provide the necessary forecast accuracy. The principal component analysis method offers a promising prospect – reducing the volume of processed data (dimensionality) without significant loss of information, which simplifies forecast models while maintaining their accuracy. Aim. To develop an accurate and efficient model for forecasting electricity consumption at industrial enterprises using the principal component analysis method. This model is aimed at eliminating the limitations of traditional forecasting approaches by reducing data dimensionality and increasing the accuracy of predictions, which ultimately improves the efficiency of electricity consumption and reduces financial costs, including those due to forecasting errors. Methods. The principal component analysis method, which allows us to reduce the volume of processed data (dimensionality) by transforming a large set of correlated variables into a smaller set of uncorrelated principal components. The study included the following stages: data import and factor analysis, correlation matrix construction, analysis of selected and accumulated variances for each factor, factor loading matrix construction, dimension reduction, development of a mathematical model using linear regression, and forecast installation and validation. Results. The application of the principal component analysis method allowed us to create a model for forecasting electricity consumption. Its application showed that the first principal component explains 69.65% of the total variance, the second component – ​​17.28%, i. e. together they explain almost 87% of the variance. The developed model provides good agreement between the actual and forecast values ​​of electricity consumption in several time intervals with an average error level within the range of +3 to –5%. This indicates the suitability of the model for forecasting electricity consumption, although some discrepancies indicate the need for its further improvement.

Relevance. The need to improve the oil recovery factor from carbonate reservoirs by increasing sweep/displacement coefficients, as well as by searching for ways to improve the efficiency of the reservoir pressure maintenance system. Aim. To increase the efficiency of developing carbonate reservoirs using a reservoir pressure maintenance system through an integrated approach to studying the impact of injected fluid on reservoir systems with natural and man-made fracturing. Objects. Bashkir (C2bsh) and Vereisky (C2vr) Middle Carboniferous objects of the Dachnoe structure of the Dachnoe deposit of the Republic of Tatarstan, tectonically confined to the Ulyanovsk structure of the South Tatar arch. Methods. Seismic, acoustic, radioactive, hydrodynamic methods, as well as methods of ground microseismic monitoring to identify the nature of the activation of natural and man-made fracturing during hydraulic fracturing and cyclic injection into injection wells. Results. The authors have carried out an analysis of the hydrodynamic system of carbonate reservoirs of the Vereiskian-Bashkirian deposits; identified filtration channels; assessed the direction of injected fluid movement; carried out the analysis of the impact of the formation pressure maintenance system on producing wells at various injection modes and compensation levels in carbonate reservoirs. When carrying out hydraulic fracturing in the reservoirs under consideration, it was established that the crack propagates to both objects, thereby forming a single hydrodynamic system. The conclusions obtained from the work indicate the effectiveness of the system for maintaining reservoir pressure in these carbonate reservoirs. Clarification of data on the filtration channels of both the working agent and the oil displaced by it, in combination with knowledge of the rates of movement of the injected liquid and its distribution profiles, makes it possible to effectively manage the oil field development.

Relevance. At this moment, one of the types of ecological disadvantage is the presence of sulphate-calcium waste in hydrogen fluoride production, referred to in scientific and technical literature as fluorangydrite, which pollutes the environment in places where the production facilities are located not only in the Russian Federation, but also in other countries. The use of fluorangydrite, a solid waste of the above-mentioned production, as a raw material for construction products will not only reduce the negative impact on the environment, but also occupy a new niche of the market of construction products, obtaining economic profit. Earlier the employees of Tomsk Polytechnic University developed several directions of fluorangydrite application in construction industry with different profitability coefficients. Aim. Development of variants of obtaining highly profitable resource-saving construction products on the basis of technogenic anhydrite binder, which is an alternative to natural mineral – anhydrite, in the form of building products such as channel and floor screed. Results and conclusions. The paper introduces the information on safety of this type of building products based on the results of radiological study of technogenic anhydrite from Siberian chemical plant. The authors have revealed the grinding intensity impact on fluorangydrite neutralization time. They determined the compositions of components of new building products, some their properties, including those depending on the ratio of water and gravel screening, as well as on the time of mixing the mortar, the dependence of strength and water resistance of anhydrite building samples on the content of water and gravel screening.