Volume 336, Nº 1 (2025)

Relevance. The need to use an innovative method of thermochemical conversion of wet biomass and organic waste – hydrothermal liquefaction. This paper focuses on the further application of the by-product of the process – solid coal residue (biochar). The obtained solid residue is proposed to be used as sorbent. Aim. To evaluate the sorption capacity of carbon residues from hydrothermal liquefaction of common reed, as well as to select methods for their activation. Object. Hydrochar produced by hydrothermal liquefaction from plant biomass – common reed (Phragmites australis). Methods. Hydrothermal liquefaction, chemical activation of hydrochar sorbents by hydrogen peroxide and vapor-gas activation, sorption capacity by methylene blue, elemental analysis, specific surface area measurement by the Brunaer, Emmett and Teller method, nitrogen sorption–desorption at 77 K. Results. Sorbent yield during activation was 45 and 30% with chemical activation and 91% with steam-gas activation. The maximum sorption capacity for methylene blue of 18.4 mg/g was achieved due to chemisorption for the sample after carbon activation with peroxide in the presence of sulphuric acid. The maximum BET surface area (18.47 m²/g) and total pore volume (0.186 cm³/g) were achieved for the sample after gas-vapor activation. Based on the results of porous structure evaluation, the mesoporous structure of the obtained coals was discovered. The obtained coals showed sorption properties as good as those of similar cheap waste sorbents. The authors have proved the possibility of using the obtained sorbents for solving environmental problems, including wastewater treatment.

Relevance. The complexity of monitoring and diagnosing the condition of underground structural elements of sucker rod pumping units and large economic losses when operating this equipment with defects not identified in a timely manner. Aim. Development of methods for detecting faults in a sucker rod pump that do not require the involvement of highly qualified personnel for diagnosis, using information that is easily available on the surface. Methods. Machine learning methods (Decision tree method, K-nearest neighbors method, Support vector machine, Naive Bayes classifier) using motor power curves. Results and conclusions. The paper demonstrates the possibility of detecting faults in a sucker rod pump based on machine learning methods. The study was carried out on the basis of a developed simulation model of a sucker rod pump, used to reproduce motor power curves, taking into account the impact of the features of various equipment operation scenarios. Being the fundamental energy source for the oil production, motor power is directly related to the real-time operating condition of the oil well, and the motor power curve is a reliable source with the ability to increase the efficiency of sucker rod pump diagnostic. To train the machine learning classifiers and evaluate their performance accuracy, a number of characteristics were used, obtained from motor power curves for six different pump operating states. Namely, operating coefficients were calculated, representing the ratio of the power integral at each of the four stages of the installation operating cycle to the power integral for the entire cycle. The results show that the considered approach allows for high accuracy in diagnosing the operating conditions of a sucker rod pump. The classifier based on the decision tree method showed the highest efficiency among the four studied classifiers in identifying all six types of faults (95.8%), and the support vector machine method showed as well very high efficiency (90.3%).

Relevance. Determination of sedimentation conditions of sandy reservoir rocks is an important part in the search for new deposits and in effective development of hydrocarbon fields. Boron content in sandstones allows establishing the palaeosalinity of the sedimentation environment. There are many different methods for determining boron concentration from cores, but often the quality of the rock material extracted from the well does not allow such studies to be carried out, or the core from the required interval has not been sampled at all. Therefore, there is a need for alternative techniques to study boron content in reservoirs. Aim. Determination of relative boron content in sandstones of the Yaronga Formation of one of the fields of the Yamal Peninsula based on the data of geophysical well surveys and identification of the regularities of its accumulation taking into account the facies settings identified using classical methods. Methods. Determination of geochemical parameters from the data of geophysical well surveys, identification of electrofacial patterns using the methodology of V.S. Muromtsev, classical methods of determining the conditions of sedimentation from the data of core and geophysical well surveys. Results and conclusions. The relative boron content in terrigenous reservoirs has been determined only on the basis of geophysical well studies. The authors have established the facies conditions of sedimentation of rocks in the study area and revealed the relationship between boron concentration in sandstones and conditions of their sedimentation. It was found that the intensity of boron accumulation in terrigenous reservoirs is mainly related to the hydrodynamic activity of the sedimentation environment, taking into account the palaeosalinity of the basin. The relative boron content when superimposed on the facies map allows us to obtain additional information not contradicting that obtained using traditional methods.

Relevance. Currently, the issue of using hydrogen as a fuel replacing hydrocarbon raw materials is widely discussed. Plans for hydrogen energy development, announced in a number of countries, including Russia, imply a manifold increase in hydrogen production and consumption for energy purposes. It is still premature to draw clear conclusions about the possibilities of industrial-scale production of free hydrogen emanating from the depths of the Earth. Therefore, hydrogen is produced mainly by coal and gas conversion. However, the only environmentally friendly way to produce hydrogen is to extract it from water, which is much more abundant on Earth than hydrocarbons and which is more accessible. The most common way to obtain hydrogen from water is the decomposition of water under the influence of electric current in an electrolyzer. By using renewable energy sources, the hydrogen production will be environmentally friendly. Aim. To study the economic efficiency of hydrogen production by electrolysis based on electricity generated by wind power plants and photovoltaic converters, depending on the configuration of the power system and external conditions. Methods. The cost of produced hydrogen was determined depending on the technical and economic indicators of energy sources, wind speed and the arrival of solar radiation on the earth's surface. Calculations were carried out using the optimization mathematical model REM-2 (Renewable Energy Model). Results. The authors have constructed the graphs of electricity and hydrogen cost dependence on climatic conditions (average long-term wind speed and annual solar radiation). The authors carried out the analysis of the obtained results. It is shown that under good climatic conditions (V≥6 m/s, Q≥1400 kW×h/m²/year) and optimistic values of technical and economic indicators, the cost of hydrogen is 2.8–3.4 $/kg. In an autonomous power supply system, due to the use of “excess” electricity from renewable energy sources operating in stochastic mode, the costs of hydrogen production are minimal.

Relevance. The Middle Jurassic carbonaceous deposits of the Ulug-Khem basin (Republic of Tuva, Russia) are an available for studying stratigraphic analogue of the source rocks of the oil and gas basins of China (Xishanyao formation J₂x) and Western Siberia (Tyumen formation J₂tm). The study of their generation properties will allow us to predict the distribution zones of coal-bearing source rocks in adjacent poorly studied areas. Aim and methods. Assessment of the hydrocarbon potential of the Ulug-Khem basin coals based on the results of Rock-Eval pyrolysis. Results. According to pyrolysis data the Middle Jurassic coals of the Ulug-Khem basin have significant hydrocarbon potential. Kerogen is represented by a mixture of types II and III, vitrinite and liptinite in different proportions. The liquid and gaseous hydrocarbons generation potential of coals from the Mezhegey and Elegest coal fields has been mostly realized. The amount of hydrocarbons that could have been produced by the coals reaches very high values – 100–170 mg HC/g of rock. Comparison of the Ulug-Khem basin coals and the Middle Jurassic source rocks of Western Siberia and a number of basins in China shows the similarity of their organic matter. The hydrocarbon generation potential of the organic matter of the Middle Jurassic coals and their analogues can be realized in the sedimentary basins of Mongolia.

Relevance. West-Magnitogorsk zone (Southern Urals) hold a lot of Early Carboniferous gabbroic and granitoid intrusions, which associated with various mineralization types (Ti-Fe, Cu-Ni-PGE, Au), but information about REE mineralization is scarce. Contact hydrothermal-metasomatic processes rarely form the economic REE mineral deposits, but they can provide valuable information about the behaviors of rare earth elements. Aim. Mineralogical and geochemical characteristics of metasedimentary rocks from exocontact zone of the Khudolaz complex gabbro massif, study of rare earth minerals, determination of the formation conditions and sources of mineralizing fluids. Methods. Minerals were studied using optical and scanning electron microscopy; the bulk composition of the rocks was determined by XRF and ICP-MS analytical techniques; vapor-liquid fluid inclusions in calcite were studied using microthermometry and Raman spectroscopy; the isotopic composition of carbon and oxygen was determined for metasedimentary silicate-carbonate metasomatites. Results and conclusions. In the Khudolaz complex gabbro massif exocontact zone, the Zilair Formation sedimentary rocks undergo recrystallization associated with hydrothermal-metasomatic processes and manifested as the formation of globular and granoblastic textures, stylolites, the formation of metacrystals of various rock-forming and accessory minerals, including rare earth minerals (synchisite-(Ce), CaCe(CO₃)₂F, and REE-rich clinozoisite, (Ca,REE)₂Al₃O[Si₂O₇][SiO₄](OH)). According to microthermometry of vapor-liquid fluid inclusions in calcite, the formation of REE-bearing minerals occurred at temperatures not lower than 150°С. The sources of rare earth elements could be both the Zilair Formation sedimentary rocks and gabbro, as evidenced by the increase in REE concentrations and isotopic composition of oxygen and carbon in silicate-carbonate metasomatites (δ¹⁸O_SMOW =13.80…15.98 ‰, δ¹³С = –5.64…–2.18).

Relevance. Progressive degradation of farmland soils – erosion, salinization, desertification. Aim. To establish features of water-physical properties of leached chernozem under an apple orchard and associated patterns of soil profile moisture distribution in summer period when precipitation deficiency observed. Methods. Moisture content in soil horizons was determined by the gravimetric method. To determine the granulometric composition of soils, the pipette method was used. The soil bulk density was determined by the cutting ring method. For solid phase density determination the pycnometric method was used. The method of graphic interpolation was used for transition the soil texture classification from Russian to international one. Water infiltration modeling into the soil profile was carried out using the HYDRUS-1D program. The parameters of approximating of the water retention curve of soils by the Van Genuchten equation were obtained by the calculation method of pedotransfer functions «Rosetta Lite» of the RETC program, using data on soil density and soil texture. Results. It has been established that the upper well-structured horizons of leached chernozem under an apple orchard have a greater water-holding capacity; their water-retention curves are more flattened. The water retention curve of the more structureless B2k horizon, the soil texture of which is dominated by sandy fractions, is shifted towards lower humidity. During hot and dry summer period the moisture deficiency in the soil was noted only in the upper twenty-centimeter soil column (14 mm). The moisture of the lower horizons, where the bulk of tree roots are concentrated, is satisfactory. The model demonstrates the smallest discrepancies with the moisture values measured during the soil reclamation experiment one day after the start. The downward moisture penetration into the lower soil layers is prevented by low pressure in the clayey A and AB horizons. Selection of input parameters and debugging of the model based on experimental data allows it to be used to simulate further processes occurring in the soil. It was revealed that the formation of positive (upward) water flows, which ensure the “pull-up” of salts and substances from the lower part of the profile to the upper layers during dry periods of the year, has a significant impact on moisture distribution in the chernozem under the apple orchard.

Relevance. The desire to increase the energy efficiency of industrial enterprises and reduce greenhouse gas emissions from their activities. Reducing specific energy consumption at large oil refineries and petrochemical plants is not new and is quite widely used. Dozens of monographs and thousands of articles are devoted to these areas. But it should be taken into account that in the oil refining industry, all crude oil, even that which does not reach the refinery, necessarily passes through oil preparation and stabilization units at the fields. Therefore, in order to create energy-efficient and environmentally friendly processes throughout the entire oil refining chain, it is necessary to increase the energy efficiency of the oil preparation and stabilization units located at the fields. There are very few research works on thermal energy integration of oil preparation and stabilization units. Aim. Determination of target design and energy values for an energy-efficient retrofit project of the heat exchange network for the surveyed oil preparation and stabilization units and of its energy efficiency potential. Methods. Pinch analysis methods are used to determine the target values of an energy-efficient retrofit project. Mathematical modeling of heat exchange processes in the heat exchange network and economic analysis were performed using the Pinch 2.02 software; the Aspen HYSYS software package was used to create a simulation engineering model of the oil preparation and stabilization units. Results. When determining the target values of the heat exchange network retrofit project, the cost of energy and heat exchange equipment, the cost of collectors for splitting process streams, and technical restrictions on the placement of heat exchanger sections were taken into account. The inclusion of fuel gas in the process stream table has allowed the definition of target parameters for the optimal unit heat exchange network design to evolve. In the process of evolution of target values, the energy efficiency potential of the surveyed oil preparation and stabilization units was determined, which shows the possibility of reducing specific energy consumption by 77%. Upon implementation of the heat exchange network retrofit project and achievement of target parameters, the following economic results will be obtained: IRR=42%, NPV=7425780 USD, DPP 4 years. Also, CO₂ emissions can be reduced by 30 thousand tons per year. It should be noted that the evolution of target designation and all target values for the reconstruction project were obtained before the implementation of the heat exchange network oil preparation and stabilization units project itself. 

Relevance. Today, most of the fields exploited in the Russian Federation have moved to the final stage of development, which entails an inevitable increase in the number of factors complicating hydrocarbon production. One of these factors is the increased water cut of the extracted products. This problem is the cause of increase in specific energy consumption for liquid production, growth of the cost of separating oil and water in the collection and treatment system, as well as increase in the number of equipment failures due to corrosion, deposition of mineral salts and the formation of persistent oil-water emulsions. In many fields, the level of water cut in products already reaches 98–99%, which is the limit of profitability of production and requires the adoption of measures aimed at reducing the share of produced water. Costs become an order of magnitude higher when it comes to horizontal wells, due to the higher complexity and cost of the work carried out on them. Aim. To increase the efficiency of water isolation work in horizontal production wells by determining the most suitable chemical composition to limit water inflow, which would meet the requirements and be available in large quantities to a wide range of domestic oil and gas companies. Objects. The analysis of measures to reduce the water cut of well products. Subject. Various chemical reagents for isolating water inflow and methods for determining the suitability of a well for water isolation work. Methods. General scientific methods (analysis, generalization, synthesis, classification) and specific scientific ones (mathematical modeling, software modeling). The set and combination of these methods are adequate to the goals and objectives, object and subject of research of this work. Results. The authors have carried out a study to improve the efficiency of horizontal wells in conditions of increased water cut of produced products. Based on the research the most effective method of limiting water inflow – the use of gel-forming compositions – was determined. Modelling of polymer flooding was carried out in the tNavigator software package and two development scenarios were compared. The authors developed the metho-dology for selecting candidate wells for waterproofing work, implemented in the form of a computer program written in the Python programming language.

Relevance. The necessity to develop in Russia the technologies that use non-traditional energy sources. The formation of these technologies will allow providing energy resources to the population without harmful emissions into the environment. Aim. Comprehensive analysis of the operating characteristics of a binary geothermal power plants in various climatic operating conditions. Objects. Thermal diagrams of binary geothermal power plants applicable to installation in different geographic regions and operation from different geothermal sources. Methods. Numerical studies based on mathematical algorithms of binary geothermal plant systems, comparative analysis of the efficiency of binary geothermal plants based on various external parameters. Results and conclusions. Numerical studies have been conducted to determine the efficiency of geothermal power plants with a binary thermal circuit and an air-cooled condenser were conducted during their operation on various sources, for which 15 known geothermal sources located in Russia in different geographical regions were selected. Possible operating parameters of binary geothermal power plants were analyzed based on the known characteristics of the fluid at the well outlet. Since the geothermal power plant has an air-cooled condenser in its thermal circuit, its operating parameters were obtained from the average monthly ambient air temperatures in the calendar year in the region where the analyzed geothermal source is located. Numerical studies showed the impact of thermal source parameters and climatic features on the efficiency of electric energy generation by means of a binary plant. It was revealed that with the possible operation of a binary geothermal plant during a calendar year, the highest average monthly electric power is expectedly achieved in the cold period of time, in this case in January, and is 1752 kW for the Mogoysky hot spring. For the warmest month of the year – July – the binary power plant of the Mechigmen hot spring could have the greatest electric power of 930 kW. The greatest absolute electric efficiency in January reaches 15.22%, depends to a greater extent on the value of the temperature of the heat supply in the cycle and among the binary stations considered in this work, the geothermal power plants in the settlement of Chazhemto could have it.