The forest-steppe landscapes of the Stavropol Upland are an important object of study for the microelement composition of soils due to the significant presence of agricultural lands with fertile soils in the land use structure. The study methods were comparative geography and landscape geochemistry, identifying mesocatenas within the main elementary landscapes and encompassing the soil-geochemical interfaces characteristic of the forest-steppe landscapes of the Stavropol Upland. It was established that the soils of the forest-steppe landscapes of the Stavropol Upland exhibit specific features of the radial and lateral soilgeochemical patterns of microelement migration. In the radial differentiation of the total contents and pseudototal forms of Cu, Zn, and Cd, and the exchangeable forms of Cd in the profiles of dark gray forest soils and typical chernozems, a surface-accumulative distribution predominates. Eluvial-illuvial distribution is observed for the total contents and exchangeable forms of Pb. Lateral differentiation of the total contents and pseudototal forms of Cu, Zn, Pb, and Cd within the established landscape-geochemical mesocatenas is non-contrasting, which is associated with the significant capacity of biogeochemical barriers. An accumulative type of lateral differentiation was established for the exchangeable forms of Cu, Zn, and Cd. Based on the characteristics of the main soil-forming processes, the properties of soil masses, the features of the radial and lateral soil-geochemical structures, and the composition of the leading phases-carriers of microelements in soils, a forest-steppe type of formation of the microelement composition of soils was identified. The results of factor analysis using the principal component analysis (PCA) showed that Corg and pH act as predictors in the forest-steppe type of formation of the microelement composition of soils, explaining 32.8% of the total variance. It is likely that the formation of biogeochemical and alkaline geochemical barriers significantly affects the distribution of microelements in the soils of the forest-steppe landscapes of the Stavropol Upland.

The study presents satellite monitoring of changes in the state and boundaries of the Bolshoy Azau Glacier and the transformation of periglacial landscapes over the period 2015-2025. Based on Sentinel-2 (Level-2A) multispectral data, using the Normalized Difference Snow Index (NDSI), visual interpretation, and the NDVI vegetation index, the assessment of glacier area dynamics, the ratio of clean and debriscovered ice, and the features of primary succession on deposited moraines was made.

It was established that over the ten-year period the total glacier area decreased by 4.53 km² (24.1%). The proportion of debriscovered ice increased from 2.9% to 50.4%, accompanied by the active transformation of debris-covered ice into deglaciated moraine deposits, the area of which reached 4.45 km². Analysis of NDVI values on these moraines revealed extremely low values (mean 0.0018), indicating the initial stage of primary succession or its near absence. The obtained results indicate the persistence of high geomorphological instability within the periglacial zone and an increased risk of glacial debris flows in the upper reaches of the Baksan River basin. It is shown that even a temporary slowdown in deglaciation rates does not guarantee landscape stabilization. The use of geoinformation analysis and remote sensing technologies ensured high accuracy of calculations and broad temporal coverage for monitoring and studying the dynamics of glacier surface changes, and also allowed identification of the spatiotemporal patterns of glaciation degradation and analysis of the transformation of adjacent geosystems under contemporary climate change conditions.

The article focuses on identifying urbanization features of ethnic groups residing in Russia. The study is based on data from the 2021 All-Russian Population Census and the 1989 All-Union Population Census – the only sources containing information on ethnic composition of urban and rural populations at all administrative-territorial levels. The authors have compiled a database Ethnic Processes of the Urban Population in Russia, which was processed at QGIS GIS platform. It has been established that out of 194 ethnic groups, 98 have completed the urbanization transition (with the share of urban residents exceeding 50 %), that amounts to 80.2 % of the total urban population of the country. The most urbanized ethnic groups are Russians (76.3 %; 80.6 million urban residents), as well as Jews (95 %), Georgians (78 %), Kyrgyz, Uzbeks, and Tajiks. Moderate urbanization (50-75 %) is observed among Tatars, Ukrainians, and Armenians. The least urbanized (less than 25 %) are 35 ethnic groups, including 13 small in number indigenous peoples of the North. For ethnic groups with compact settlement areas, intra-regional urbanization is typical: titular ethnic groups are concentrated in originally ethnic republics, and especially in regional capitals. In the post-Soviet period, the share of urban residents has grown most significantly among Tuvans, Chukchi, Chechens, Lezgins, and others, who had lower urbanization levels in the late Soviet period. At the same time, no significant changes are observed among ethnic groups that already had high urbanization rates by 1989.

The subject of the study is the current state of the physics of convective clouds and weather modification. It is noted that the pace of development in this scientific field has significantly declined since the late 1980s. Traditional analytical approaches, focusing on the state of research into “elementary” cloud processes, failed to identify the reasons for this slow-down. By analyzing the state of convective cloud physics and weather modification from the perspective of system development stages, these reasons have been established. It has been found that the present period represents a transitional phase for this scientific field, characterized by a shift from studying “elementary” processes toward investigating clouds as integrated systems. The study analyzes the main trends in the physics of convective clouds and weather modification, specifies the objectives of these directions, and examines methodologies for modeling the role of systemic properties in cloud formation. Some research results concerning the role of such systemic properties as cloud-environment interaction and internal cloud process interactions in shaping cloud structure are discussed. Previously conducted studies based on a three-dimensional non-stationary model and a two-dimensional microphysical model of hail clouds with prescribed thermohydrodynamics are reviewed. It has been established that cloud formation processes are most sensitive to wind speed variations in the lower troposphere. It has been revealed that hail growth occurs within the temperature range of –10 °C to –25 °C, and precipitation processes exhibit a cyclic character. An algorithm for developing weather modification techniques for hail clouds, taking into account their synergistic properties, is proposed.

The object of the study is clusters of zinc oxide nanoparticles. The article studies of the condensation properties of zinc oxide as a promising reagent for fog dispersion. Zinc oxide (ZnO) is known to be a hydrophilic substance, but its properties in relation to water may vary depending on the conditions in which it is located and the structure of its surface. The research was carried out at laboratory facilities of the High-Altitude Geophysical Institute in an artificial cloudy environment at positive temperatures. A set of equipment was used, including a large cloud chamber, a particle counter, and a fog generator. A reagent is placed in a large cloud chamber, an artificial fog is created, and the reagent is thermally sublimated. Before and after distillation, a particle counter is sampled. At the bottom of the cloud chamber, substrates are opened to collect droplets, which are examined with a microscope. To determine the hygroscopic point of zinc oxide, a zinc oxide sample is placed under a glass cap and vacuum is created at a certain temperature. Water vapor is gradually introduced, increasing the relative hu-midity and determining the amount of adsorbed water. As a result, it was found that during the sublimation of zinc oxide, more water vapor begins to be successfully adsorbed already at a relative humidity of 75-80 % and larger droplets are formed. Due to the hygroscopic microstructure of ZnO, which attracts a large amount of water vapor and turns it into liquid faster, the concentration of droplets of 10 microns increases by 20 times, and the concentration of droplets of 25 microns increases by 9 times relative to the background. It was found that the artificial fog completely dissipates 5 minutes after the application of zinc oxide. Without exposure to the reagent, visibility in the cloud chamber began to change after 15 minutes and the fog completely dissipated within 25 minutes.

During the development of gas condensate reservoirs, the extracted product contains not only “dry” gases but also liquid hydrocarbons. These hydrocarbons are unstable in both content and the composition of the reservoir mixture as reservoir conditions change due to phase transitions. Therefore, to forecast development, it is advisable to use experimental data in geological and technological modeling. The compositional PVT model (construction of phase process diagrams) requires current data on the component composition of fluids. This information is important for obtaining accurate initial parameters for field development forecasting. The study notes that to achieve a positive result with an accuracy of approximately ±3 to 5%, the following conditions were met during the study: the capacity of the field separator ensured the entrainment of liquid droplets in the reservoir mixture of no more than 4 cm³/m³. Based on integrated measurements taken during separation sampling, the condensate-gas ratio (CGR) and the physicochemical characteristics of the condensate (density, dynamic viscosity, and other properties) were determined. Based on the analysis of the obtained results, the saturated condensate yield (SCY) was determined; it varied over a wide range, ranging from 69.8 g/m³ to 513.2 g/m³ of separation gas. Changes in the gas condensate mixture properties were observed with a decrease in reservoir pressure from 29.89 to 26.33 MPa. This decrease in pressure led to the formation of a depression funnel in the near-wellbore zone and resulted in the influx of a two-phase hydrocarbon mixture. Also, based on the PVT data, the dependences of the precipitated liquid phase on pressure were constructed for the gas condensate system under study. The predicted condensate recovery factor was experimentally determined, and the condensation pressures of hydrocarbons in the reservoir system were measured.

The paper examines the modeling of technological processes in hydrocarbon field development using the tNavigator software package by the example of simulating hydraulic fracturing and potential hydrate formation zones. The relevance of modeling is associated with the need to improve the efficiency of field development man-agement, reduce costs and risks in hydrocarbon production. It is noted that, by ensuring mathematical environmental safety, modeling allows for the verification of the feasibility of technological solutions for developing complex reservoirs using a digital 3D hydrodynamic model. It is substantiated that the model allows for evaluating the effectiveness of the proposed inflow stimulation method, the impact of specific parameters on development success, and a comparison with other solutions, including the creation of a predictive version of the model for planning high-quality field development. The purpose of modeling technological processes in the tNavigator software package, for example, to identify potential hydrate formation zones, is to construct an equilibrium curve for hydrate formation, define logical expressions, and create special properties.

The following methods are used to simulate hydraulic fracturing (GRP): skin factor, perforation productivity factor modification, virtual perforation creation, and wellbore grid refinement. The skin factor method is used for small fractures smaller than the cell size. The fracture is accounted for by penetrating the overlying and underlying modeling objects, but does not account for the horizontal orientation of the HF fracture. The virtual perforation method creates additional virtual perforation intervals in the cells through which the fracture passes. Perforation conductivity coefficients are calculated using semi-empirical relationships that take into account cell and fracture parameters. The tNavigator software package lacks functionality for identifying and displaying potential hydrate formation zones in a 3D model. To address this issue, a custom property was created, in which a logical expression was defined in the Python programming language, allowing for the identification of the required zones. An equilibrium hydrate formation curve was constructed using a compositional thermal model for a given gas composition. Using MS Excel 2010 software, the equilibrium hydrate formation curve was plotted using coordinates exported from tNavigator. The dependence of the equilibrium hydrate formation temperature on the equilibrium hydrate formation pressure was determined, described by a logarithmic equation. tNavigator can be used to simulate hydraulic fracturing, near-wellbore treatment technologies, enhanced oil and gas recovery methods, and other interventions. Several hydraulic fracturing modeling methods are considered, including skin factor simulation, virtual perforation generation, and wellbore grid reduction. A methodology for constructing an equilibrium hydrate formation curve in tNavigator is discussed. A calculation was performed to determine the equation describing the hydrate formation curve. Using the Python programming language, logical expressions were defined to identify zones of potential hydrate formation. Calculations were performed using a hydrodynamic model based on real field data. A thermal compositional hydrodynamic model was created, allowing for tracking the distribution and change in reservoir temperature during development. The feasibility of predicting and identifying zones of potential hydrate formation under various pressure-temperature conditions and wellbore stimulation methods is demonstrated. Some of the advantages of using tNavigator include high calculation performance on modern multi-core, multi-processor hardware, a user-friendly graphical interface, support for all data formats, and a range of unique tools for modeling geological and technical interventions.

Under the conditions of high-viscosity oil production intensification and rising energy costs, optimizing heat flows at well production treatment units is a key factor in reducing operational expenditures. Redirecting scarce water steam for enhanced oil recovery needs requires identifying alternative heat sources for internal technological processes. The paper aims to evaluate technological feasibility and efficiency of complete or partial substitution of water steam with an alternative heat medium, specifically hot oil-containing liquid from an adjacent oilfield, within an inlet heat exchanger block. The study was conducted using computer thermodynamic modeling methods, which served as the basis for developing a digital model of the shell-and-tube heat exchanger block with rigorous tube bundle geometry, while the characterization of high-viscosity emulsions was performed based on actual laboratory data of narrow fraction distillation. The simulation analysis proved that a complete replacement of steam with the oil-containing liquid is impossible due to a deficit in the existing heating surface area. Transitioning to a single-phase medium leads to a 45% decrease in the heat transfer coefficient caused by the high viscosity characteristics of the oil. To address this issue, a combined operation mode of the block was developed and substantiated, providing for the joint utilization of two types of heat exchange media (steam and oil-containing liquid). The proposed scheme ensures stable maintenance of the standard oil treatment temperature at 82°C while simultaneously reducing steam consumption by 21%, which releases significant energy resources for oilfield technological needs and logically justifies the necessity for a deep analysis of such systems.