The article is devoted to the problem of population migration in Russian cities and regional capitals in the post-Soviet period. The study is based on official statistics data for 1994–2023. In the context of a deep demographic crisis, migration plays an important role in shaping the population of Russia. At the beginning of the post-Soviet period, under the influence of new factors for Russia (the collapse of the USSR, the socio-economic crisis, the aggravation of interethnic relations, etc.), the scale and geography of migration flows changed, and the regions that received and sent migrants switched roles. The eastern migration trend has been replaced by the western one. The study identifies the features of migration processes at each stage of the post-Soviet period. At the beginning of the post-Soviet period, the zone with a positive migration balance in cities included most of European Russia, with the exception of the northern regions, as well as Western Siberia and the regions of Eastern Siberia. Gradually, the zone with a positive migration balance in cities has been shrinking, and now there is a positive migration growth in the cities of the Far East. The regions and regional capitals differ in terms of the nature of migration processes: approximately 10% of them have a steady high migration growth, while the same number have a negative migration balance, and the remaining regions have varying migration balances depending on the migration situation in the country. Modeling migration processes using the centrographic method showed that the center of migration settlement shifted from the south of Yakutia to the border between the Urals and the Volga region during the study period, while the center of migration arrival moved around the capital region.

The object of the study is the changes in the regional climate, its impact on the production of agricultural crops and the creation of a model of winter wheat yield in the steppe zone of the Kabardino-Balkarian Republic (KBR). The study is based on the analysis of climate changes at the steppe meteorological station Prokhladnaya (KBR). In the period 1961–2024 the increase in average annual temperatures was 0 37 °C/10 years (D = 46 %) with the highest growth rate in the summer season (0 48 °C/10 years, D = 50 %). During the study period, there was a slight positive trend in annual and seasonal precipitation amounts, with the exception of the summer season (a decrease of 5 2 mm/10 years) and the spring season since 1976 (a decrease of 0 18 mm/10 years), when sufficient soil moisture is needed. It was found that climatic changes in the steppe zone of Kabardino-Balkaria are manifested in an increase in the duration and intensity of hot weather. There is a slight decrease in precipitation in summer with a simultaneous increase in the intensity of heavy rainfall, and aridity increases in summer. Since the yield of agricultural crops depends on the interaction of various environmental factors and the specific characteristics of each plant species, this paper proposes a new approach to improving the information support for the task of reducing risks in agriculture, associated with a lack of moisture in the soil using the steppe zone of the KBR as an example. This approach involved using the values of the soil moisture supply coefficients calculated based on average monthly precipitation in March, April, May and in the summer season, and average monthly temperature in the same periods for 1961–2024 at the Prokhladnaya station. Using the least squares method, the parameters of the actual equation for calculating the yield of winter wheat were obtained. The results of the correlation analysis between the actual and estimated yield values at a 1% significance level (r = 0 54, Sig. = 0.001 < p = 0.01) showed good agreement between the actual yield values and the model ones calculated using the model formula. The new multiplicative model of winter crop yield can be used to assess changes in the yield of winter crops depending on changes in temperature, precipitation, and soil moisture in the summer and spring seasons for the lead period.

Hailstorms cause significant economic damage, especially in the agricultural sector. However, hail forecasting is performed with insufficient accuracy. Determining hail size, which directly affects the magnitude of losses, is also challenging. This study aims to estimate the maximum hail size based on atmospheric meteorological parameters. To this end, we compiled data on maximum hail size recorded by the Stavropol Militarized Hail Suppression Service, together with the corresponding temperature, humidity, wind direction, and wind speed at standard isobaric levels from a global atmospheric model, used as a substitute for upper-air sounding results. The study was based on neural-network modeling methods, with the diameter of the fallen hail as the dependent variable and atmospheric parameters as the independent variables. The SPSS environment automatically selected a neural model consisting of a single layer with four neurons. According to the results, the errors on the training and test samples were identical, indicating the adequacy of the model. Additional quality assessment criteria, such as prediction and residual plots, also confirmed the adequacy of the model. The key atmospheric parameters influencing the maximum hail size were found to be: the George instability index, the temperature at the convection level, the level at which the temperature difference between the cloud and the surrounding environment reaches its maximum, and the mean moisture deficit in the layer above the condensation level at an altitude of 5 km. It was concluded that the proposed neural-network model for estimating hail size can be effectively applied by services engaged in hail suppression.

The study analyzes the long-term dynamics of the snow cover of the Bolshoy Azau Glacier, located in the Kabardino-Balkarian Republic. The research covers the period from 2018 to 2024 and is based on the integration of modern methods of remote sensing (RS) with in-depth statistical analysis of meteorological data. The work involved a detailed calculation of the Normalized Difference Snow Index (NDSI), derived from long-term series of aerial photographs and satellite system data. As a result, a clear and persistent negative trend was identified, characterized by a sharp reduction in the area and duration of winter snow cover. It was established that the regression occurs at a stable average rate of approximately 0.04 NDSI units per year, indicating intensive ablation. At the same time, summer seasonal changes do not show statistically significant dynamics, remaining within the limits of interannual variability. Parallel climatic analysis revealed a significant increase in average annual and seasonal temperatures, particularly during the critical summer months, as well as a notable decrease in winter precipitation volumes, which disrupts the mass balance of the glacier. These interconnected climatic factors comprehensively and irreversibly influence the acceleration of glacier degradation, reducing its volume and area. The obtained results once again underscore the critical importance of establishing continuous systematic cryospheric monitoring and the urgent development of strategic adaptation measures. Such actions are necessary to mitigate the growing environmental and socio-economic risks directly associated with the intense transformation of the glacial cover in the vulnerable mountain environment of the North Caucasus.

The oil recovery factor in the development of oil rims remains low compared to conventional oil reservoirs, which is attributed to intensive gas breakthroughs from the gas cap, high gas mobility, bottom water encroachment, and the complexity of controlling displacement processes. In global practice, the development of such assets often leads to increased project costs, since the strategy choice is frequently determined not by geological and physical conditions but by infrastructural or economic factors. New technologies and an integrated approach to development planning make it possible to efficiently exploit these hard-to-recover resources.
This paper presents the rationale for selecting a development strategy for the oil rim of a one field in the Northern Caspian Sea, which is currently at the design stage. The complex geological structure, low effective thickness, and the presence of a gas cap require the implementation of an individual development system involving horizontal wells and reservoir pressure maintenance strategies.
The methodological basis of the study was dynamic simulation using a sector model. Four development strategies were compared: development of the gas cap, oil rim only, sequential and simultaneous production, combined with various pressure maintenance systems. The analysis showed that the highest oil recovery is achieved with the oil rim development strategy that employs a combined reservoir pressure maintenance system: reinjection of 60% of produced gas and water injection. Optimal placement of horizontal wellbores at ¾ of the height from the gas-oil contact was proposed. The obtained results may help reduce the risks of gas and water breakthroughs, improve drainage efficiency, and increase cumulative oil production compared to alternative strategies during field commissioning. The study has practical value for planning the development of hard-to-recover reserves on the shelf.

Modern development of large oil and gas producing companies requires active use of a variety of integrated design methods aimed at improving the efficiency of hydrocarbon production processes. System analysis methods make a significant contribution to the optimization of production well operating modes in both gas and oil fields.
The use of integrated design in oil and gas field development significantly improves the quality of decision-making at all key stages, including selecting process modes and determining optimal well interventions. Integrated modeling facilitates the comprehensive optimization of well operations, taking into account the surface infrastructure associated with field development. In modern oil and gas industry, integrated modeling has become the key element in design and management of oil and gas field development.
The study proposes an approach to determining the causes of flow rate variations due to influencing factors. It examines the methodologies and compares the performance of two system analysis methods as elements of integrated oil and gas field development design (nodal analysis and deterministic factor analysis) for the reservoir-wellbore-choke-flowline system. The overall objective was to study the factors influencing gas flow from the reservoir to the separator. Each of the above-mentioned system components experiences a pressure loss, which depends on the hydraulic resistance of the corresponding component. A change in even one of these components affects well productivity. In order to understand well performance all components should be considered as a single system.

The article examines the nature and extent of reservoir failure in gas field development. It studies the state of reservoir failure diagnostics and prediction in gas fields and underground gas storage facilities. Given the relevance of the issue, the need for additional research is justified to develop reliable methods for diagnosing the state of the near-wellbore zone, assessing the nature and extent of productive formation failure, and, especially, methods for predicting such processes. The causes of well operation complications due to reservoir failure in the near-wellbore zone are investigated, and possible ways to prevent them are discussed by developing a method for predicting the behavior of productive formations for various reservoir types under conditions of complex multiphase gas-dynamic and hydrodynamic flows. Geological and field data were collected, summarized and analyzed. Geological and hydrogeological conditions were examined to identify the causes of reservoir failure and other complications, and processes were forecasted to enable the development of necessary methods and technical and technological measures to prevent and manage such complications.
The influence of geological and technological parameters on the condition of the near-wellbore zone was studied, the nature, scale, and causes of reservoir rock failure were determined, and recommendations and technical and technological measures for preventing and managing reservoir failure during gas field development were proposed. For each reservoir, depending on its characteristics, a specific set of methods for obtaining information should be justified, with certain methods being predominant. The results obtained will be used to develop technical and technological measures to combat reservoir failure.

This article examines physical and mechanical properties of rocks with the aim of modeling intensification processes and exploring the feasibility of producing a high-quality fracture network during hydraulic fracturing. It also examines radioactive elements as indicators of clay content. Data on the lithological dissection of rocks based on the content of individual naturally occurring radioactive elements, based on the introduced lithological differentiation coefficient Kd, reflect the ratio of their modal gamma activity values and indicate the highest resolving power of thorium, apparently due to its association with the mineral component of the rock rather than the concentration of organic matter. The Kd for uranium (U) is significantly lower than for Th due to its close dependence on organic matter. The article examines the definition of ‘clayiness’ to understand its possible recording. In some cases, clayiness refers to the granulometric clay content, i.e. the pelitic fraction, independent of mineral composition, in which case it is possible to determine the reservoir properties of rocks. In other cases, the definition of ‘clayiness’ is associated with the presence of clay minerals in the rock, which, accordingly, indicates the presence of chemically bound water. The article also presents a method for analyzing core material using a powder diffractometer. Based on core X-ray diffractometry data, the phase composition of the rock samples was determined. Based on these measurements and field geophysics data, elastic parameters were calculated to provide the initial data for simulating fracture propagation during hydraulic fracturing. At the end of the article, porosity data from core, cuttings, and electrical logging are compared, demonstrating high convergence.