Introduction. Marine gas hydrates are an unconventional resource of natural gas that is stored in deep-sea sediments in a solid state. It has a wide distribution and large reserves, and is also considered as an important alternative energy source for oil and natural gas in the future. The United States, Japan, China and other countries have introduced relevant laws and regulations regarding this energy source and have conducted a sufficient number of scientific studies. Currently, gas hydrate extraction technologies on the Chinese shelf mainly include the pressure reduction method and the solidphase fluidization method. These methods have their advantages and disadvantages, but they are difficult to meet the needs of commercial mining.

Materials and methods of research. Gas hydrates, commonly known as «combustible ice», are mainly found in the sediments of the seabed and permafrost on land. After decomposition, they can form gases such as methane, which is a clean energy source with rich resources and various countries consider it as an important alternative energy source in the future. However, traditional natural gas resources in China are struggling to meet the demand for clean energy as a result of economic development, and the extraction of gas hydrates promises to be an effective way to solve this problem. Thus, the study of gas hydrates can not only contribute to the early commercial exploitation of gas hydrate resources in the South China Sea, but also allows us to hope for a reduction in the cost of deep-sea traditional natural gas resources.

The results of the study and their discussion. The article provides a detailed description of each method of gas hydrate extraction technology in China with a comparative analysis of their advantages and disadvantages of application in practice. Tests of gas hydrates in the South China Sea with an assessment of their results are also given as an example.

Conclusions. The article provides recommendations on the issue of gas hydrate production in the South China Sea. Recommendations are given on the need for simultaneous research of traditional technologies and breakthrough production technologies, as well as improving the technology of interpretation and evaluation of gas hydrates in the sea area, with subsequent cost reduction in terms of the entire life cycle and, as a result, the study of key equipment and technologies for deep-sea operations.

Introduction. The object of research is the carbonate deposit of the Neftekumsk suite of the Zimne-Stavkinsko-Pravoberezhnoye field (Pushkarskoye area), confined to the Lower Triassic deposits of the Eastern Stavropol. The purpose of the research is to increase the efficiency of oil field development based on the identification of zones of increased well productivity. To achieve this goal, the following tasks are supposed to be solved: assessment of the influence of tectonic and geodynamic factors; identification of zones of increased productivity of wells associated with a system of fractures accompanying zones of tectonic stresses discharge.

Materials and methods of research. The materials included geological and field data on oil deposits (including well productivity), geophysical surveys of more than 200 deep wells, seismic data, satellite images of various scales, seismicgeological profiles, structural maps, isopach maps of effective oil saturated thicknesses, maps of current and cumulative recoveries and other materials of scientific and industrial enterprises. The following research methods were used: analysis, systematization and generalization of geological, geophysical and field data, the system-aerospace method, including the classical technology of interpretation of space images. The methodology developed by the authors for identifying zones of increased productivity of wells in carbonate deposits was used, taking into account satellite imagery interpretation data.

Results and discussion. The analysis of zones of increased productivity of wells is given. It is established that these zones are predominantly linear in nature, and the linearity of the cumulative oil production does not depend on the time of putting the wells into operation. Structural factor, effective oil pay thickness, height above the contact, open porosity, oil saturation, specific oil reserves of the formation are not the determining factors of linearity. Based on the analysis of the geotectonic activity of the studied region, the influence of the geodynamic factor on well productivity was considered and it was revealed that zones of increased fracturing, which cause an increase in well productivity, are the result of tectonic stresses discharge. The established pattern of confinement of the directions of linear zones of increased fracturing is observed not only for carbonate Neftekumsk deposits, but also for terrigenous deposits in the upper part of the field crosssection.

Conclusion. This methodology has been developed for identifying zones of increased fracturing and increased productivity of wells in the carbonate deposits of the Neftekumsk suite, due to the discharge of tectonic stresses, according to the directions of the lineaments of the day surface. The results of the research can be used to issue recommendations for identifying promising additional exploration objects for infill drilling and carrying out geological and technological measures to increase the recoverability of residual reserves.

Introduction. More and more oil fields being developed today belong to the hard to recover category, the value of the oil recovery coefficient of which directly depends on the quality of the horizontal well placement along the geological section. This article describes an approach that allows planning the most effective well trajectories in terms of cumulated oil production for the period under consideration. The advantages of the developed approach over existing tools are also given.

Materials and methods of research. The article provides an analysis of the geological parameters influence on the cumulated production, using the conclusions obtained at this stage, an objective function is constructed that allows ranking trajectories at a qualitative level in terms of prospects. This logic is reflected in the developed software prototype, which can be used in conjunction with the most common hydrodynamic simulators.

Research results and their discussion. As an evidence base, a retrospective analysis was carried out with actual wells replacement and taking into account changes in the geological basis. In each of the calculations, the effect of additional oil production was obtained, with unchanged liquid production levels. Thus, it can be concluded that the coverage coefficient is increasing and previously unrelated volumes of oil are involved in the development.

Conclusions. The analysis of the results showed the possibility of applying this technique to the all wells, as well as the possibility of replication to other development facilities.

Introduction. Currently, when calculating reserves and designing the development of oil and gas condensate fields, the priority is to achieve the highest possible and economically viable condensate recovery factor. The reservoir gas condensate system of the Chayandinskoye field, along with hydrocarbon components, contains nitrogen, carbon dioxide, and helium. To assess the effect of nitrogen on the amount of reservoir condensate loss, experimental PVT studies of recombined samples of saturated condensate and separation gas taken at the field during well testing were performed. Laboratory PVT-experiments made it possible to determine the effect of non-hydrocarbon components on the amount of condensate losses in the deposit at different temperatures and its content in methane gas. Qualitative and quantitative assessment of the effect of nitrogen (N2) on the condensate solubility in the formation gas showed that it increases the pressure of the onset of condensation and increases the loss of condensate in the deposit. The analysis of the performed studies confirmed that nitrogen affects the solubility of the condensate in gases to varying degrees and that the methane-type condensates of the Chayandinskoye field have better solubility, all other things being equal.

Materials and methods of research. The works [2-9] consider laboratory studies and analytical calculations of the fluid-dynamic properties of gas condensate mixtures in the presence of nitrogen in the system, as well as other non-hydrocarbon components that affect the loss of hydrocarbons in the deposit. At present, the effect of nitrogen on the thermodynamic properties of gas condensate systems is not sufficiently studied; therefore, it is necessary to study the effect of non-hydrocarbon components on the value of the final condensate recovery factor. For this, a set of field and laboratory studies of multicomponent systems of productive horizons of the Chayandinskoye field was carried out [2, 3]. It included field studies conducted to determine the flow rate of the separation gas, the amount of unstable condensate in the separated gas in order to calculate the condensate gas factor (cm3/m3). Laboratory studies were carried out to determine the potential content of condensate in the composition of reservoir gas, the physicochemical properties of hydrocarbons and the effect of non-hydrocarbon components on reservoir losses of condensate in the deposit [5, 6]. Field gas condensate studies were carried out by specialists from OOO Gazprom VNIIGAZ and VostSibNIIGGiMS [7]. The composition of the reservoir gas condensate system was determined based on the content and volumes of separation gas and unstable condensate sampled in the same separation mode, in which the condensate yield (CGR) was determined [8]. The calculation of the formation gas composition and determination of the potential condensate content in the formation gas were carried out in accordance with the “Methodological guide on the procedure for the development, maintenance and execution of materials to justify the potential condensate content in the formation gas and the recovery factor from the subsoil” [7]. Prediction of reservoir losses of condensate from the participation of non-hydrocarbon components in thermodynamic processes is necessary to obtain initial parameters when calculating hydrocarbons, as well as designing field development” [9].

Results and Discussion. The deposits of the Botuobinsky, Khamakinsky and Talakhsky horizons take part in the development of the Chayandinskoye field; they mutually and partially overlap each other in the northeastern part of the zone. According to the type of fluid, the deposits of the Botuobinsky horizon are gas condensate and gas condensate with oil rims. Within the license area, the deposit has been explored by 74 wells. According to the results of interpretation of geophysical well surveys, the values of effective gas-saturated thicknesses lie in the range from 0,6 m to 21,3 m. The initial formation gas composition contains (% mol): methane – 85,82-83,14; ethane – 4,45-4,77; propane – 1,11-2,67; butane fraction – 0,16-0,73; pentanes – 0,25-1,22; nitrogen – 5,62-8,11; carbon dioxide – 0,01-1,69; helium – 0,30-0,48; hydrogen - 0.00-0.08. The potential content of condensate in the formation gas is up to 35 g/m3. The density of a stable condensate under standard conditions is 0,683 g/cm3, with a molecular weight of 83 g/mol. The content of aromatic hydrocarbons is assumed to be 6,46%, naphthenic – 14,93%, methane – 78,61%. In total, nine gas deposits have been identified in the Talakh horizon. They are characterized by the average formation gas composition (% mol): methane 76,74-84,98; ethane – 3,93-5,92; propane – 1,1-1,8; butane fraction – 0,1-0,5; pentanes – 0,27-0,59. In the composition of the gas, non-hydrocarbon components are as follows (% mol): nitrogen – 6,58-16,34; carbon dioxide - up to 0,47; helium - up to 1,15 and hydrogen - up to 0,52. The potential content of the condensate is up to 32 g/m3. The content of aromatic hydrocarbons is assumed to be 6,46%, naphthenic – 14,93%, methane – 78,61%. The condensates of the productive horizons of the Chayandinskoye field are of the methane type.

Conclusion. Thus, the conducted PVT experiments to identify the effect of nitrogen and other non-hydrocarbon components in natural gas showed that the design condensate recovery factor is not significantly overestimated. The results of the experiments established the negative effect of nitrogen and carbon dioxide on reservoir losses of hydrocarbons in the deposit due to the different degree of solubility of condensate in gases (carbon dioxide improves, and nitrogen worsens their solubility). Studies of samples of separation gas and saturated condensate confirmed the data that methane-type condensates have the best solubility, other things being equal. The degree of influence of nitrogen on reservoir losses of condensate in the deposit was determined for the conditions of development of the Chayandinskoye oil and gas condensate field.

Introduction. Glaciers in mountainous areas are accumulators of atmospheric moisture and at the same time one of the main sources of food for the main rivers of the Caucasus and are promising sources of fresh water. This is especially true for the rivers of the basin of the largest glaciation unit - Bezengi. But besides the shortage of fresh water, there is another problem: its quality. Purpose of the work: to give a spatial and temporal characteristic of the distribution of the concentration of heavy metals (HM) in the Bezengi and Mizhirgi glaciers, as well as in the river. Cherek Bezengi in the period from the beginning of the XXI century.

Materials and methods of research. In this work, a comparative analysis of the concentrations of HM contained in glaciers and river waters of the river basin was carried out. Cherek. Sampling was carried out starting from the source of the Cherek River, during periods with different hydrological regimes. When sampling water, the temperature of air, water and transparency were recorded. Samples were preserved with nitric acid on the day of sampling. The concentrations of the following HMs, modern priority environmental pollutants, were determined: Cr, Ni, Mo, Mn, Pb, Zn, Ag, Cu, Cd. The determination of HM content in ice samples and river waters was carried out from 2003 to 2010 at the High Mountain Geophysical Institute by the method of emission spectral analysis. Sample analysis 2012–2021 were produced by the atomic absorption method on an MGA-915 spectrometer.

Results and discussion. It was found that the chemical composition of water at the headwaters of the river and in the tongue of glaciers is closer than in the lower reaches of the river. HM concentrations at the beginning of the 21st century significantly exceed HM concentrations in recent years. In winter samples 2018−2019. in many samples, the content of some HMs is below their detection limit (L/L). The latest series of samples cover several points on the river. Cherek Balkar and after their confluence and the formation of the river. Cherek.

Conclusions. The content of HMs in one of the most powerful glaciation centers in the Caucasus, Bezengi, was studied. The results obtained make it possible to judge the migration of HMs in the system of snow-firn-ice thickness - melt waters of glacier-fed rivers at their sources. For river waters of the river basin. Cherek Bezengi and the Bezengi and Mizhirgi glaciers in the last series of winter sampling samples (2018-2019) there is a decrease in the concentration of HMs. This is due to the fact that the content of HMs in winter sampling samples is close to their content in solid sediments. And for other series of samples, the content of HMs is determined by the melting of avalanches and ice falls from the slopes, which constitute a significant part of the balance of the Bezengi and Mizhirgi glaciers and contribute to an increase in the concentration of HMs in melt waters.

Introduction. A traditional for geography study of the spatial and planning organization features of the territory has recently acquired a “new life” in strategic and territorial planning documents. At the same time, the formation of urban and municipal districts with the abolition of village councils lead to the fact that the most important link in strategic and territorial planning at the level of settlements “falls out”. Approbation of traditional geographic methods of spatial analysis in the context of urban development of the territory is the main goal of the study.

Materials and research methods. The basis of the work was a variety of data and materials: state and municipal statistics (official), cadastral registration, strategic and territorial planning documents, materials of sociological surveys and a field survey results of cities and towns that are part of the Stavropol Territory. Using the methods of systemic geoinformation analysis, a structural model of the urban development of the Stavropol Territory containing a geodatabase and cartographic bases of various scales was created.

The results of the study and their discussion. The study was carried out on different scales: the Stavropol Territory, macro-settlement areas, the main urban agglomerations of the Stavropol Territory (Stavropol and Caucasian Mineral Waters (CMW), individual municipalities). A general characteristic of the spatial planning organization of the Stavropol Territory is given, an analysis of its individual elements is made: linear (planning axes), nodal (planning centers and nodes), areal (planning zones), current trends in the development of the entire system and individual elements have been established and characterized. Five types of spatial planning zones in the territory of the region have been identified. A structural model of urban development of the territory has been developed using the methods of geoinformation analysis and mapping. The main trends in the spatial planning organization of the territory are determined – concentration and polarization. The main problems of the spatial development of the region are identified and characterized.

Conclusions. For the purposes of strategic and territorial planning of the Stavropol Territory, an analysis of the features of the spatial planning organization of the territory makes it possible to determine the territorial potentials in the form of areas and points of growth. Internal differences in the spatial and planning development of the Stavropol Territory show significant intra-regional differentiation with a high degree of geographical contrast and polarization of the territory. The asymmetry of regional development is manifested in the shift of socio-economic and urban centers of gravity in the western and southern directions - towards the main agglomerations of the region - Stavropol and CMW. The proposed structural model of urban development shows the need to take into account the role and potential of grassroots rural settlements, which are actually “erased” under the new municipal reform and the formation of large urban and municipal districts.

Introduction. Emissions from industrial enterprises, open pit mining, vehicles, etc. can change the electrical properties of the surface layer of the atmosphere and have undesirable environmental consequences for the environment and technical facilities. Studies of the electrical state of the atmosphere in clear weather were carried out in the area of the Mukulan quarry in the North Caucasus. In the course of the study, increased values of the electric field strength were observed, apparently due to the process of electrization of aerosol particles of different sizes, formed in the process of mechanical destruction and crushing of rock particles.

Materials and research methods. Measurements of the electric field strength of the atmosphere, which is one of the important parameters of atmospheric electricity, were carried out using a rotary type fluxmeter at an altitude of 2542 m. At the same time, special attention was paid to the reliability of the results obtained during these measurements. A technique was used for conducting atmospheric-electrical measurements, which excludes errors introduced by various factors, such as the method of placing the measuring equipment, the heterogeneity of the terrain, the weather conditions of the observation point, which was located in the layer of air mass exchange and turbulent diffusion.

Results of the study and their discussion. An analysis of the results obtained on days with undisturbed clear weather showed that the only factor influencing the unitary course of the field strength at such a height remains the open pit mining, where on such days there is constant intense dust formation and the associated electrization of aerosol particles of different sizes. If the processes of electrification proceed intensively and for a long time, then an excess space charge accumulates in the surface layer of the atmosphere, which contributes to the formation of increased values of the electric field near the earth’s surface. The average value of the electric field strength was 600-700 V/m, which exceeds by an order of magnitude the results of measurements carried out at such heights by other researchers in undisturbed weather conditions. Local changes in the field strength were also noted when approaching the measuring site, a visually observed cloud of dust, which manifested itself in synchronous changes in the field strength, at which its value decreases and sometimes reaches negative values and recovers after some time to its average values. Local changes in the field are caused by the action of a negative space charge concentrated in a dust cloud consisting of large particles, the average size of which was estimated from the settling rate of aerosol particles and amounted to about 30 μm. It was found that there is a direct relationship between the field strength and the concentration of aerosol particles formed during the mechanical destruction of rocks, as a result of which the particles are electrified.

Conclusions. Studies of the electrical state carried out in the area of the Mukulan quarry showed that in good weather conditions, electrization is observed in the surface layer of the atmosphere. Aerosol particles acquire a charge in the process of mechanical destruction of rock particles and disruption of contact between them. At the same time, selective charging and capture of light air ions, depending on their size, and macroseparation in the field of gravitational forces occur, on the one hand, the rapid settling of large particles charged negatively on the earth’s surface, and on the other hand, small particles that can be in suspension for days in the atmosphere, charged with a positive sign, which leads to a decrease in air conductivity and, accordingly, an increase in the field strength in the quarry area.

Introduction. In October 2021, a team of authors made an expedition to the Ivanovo region in order to study the demographic development of the urban agglomeration, the core of which is the center of this region. On the basis of travel observations, general geographical, with an emphasis on socio-economic processes, mini-portraits of the cities of Ivanovo, Kokhma, Shuya, Vichuga, Teikovo, Gavrilov Posad, Plyosa, and the town. Palekh and Kineshma, which is not part of the agglomeration.

Materials and methods. The key research method is visual observation and a survey of the local population. The work also used official statistics on the population of settlements.

Results and discussion. The article gives mini-portraits of settlements in accordance with the classical scheme of the economic and geographical characteristics of the territory, namely, it describes: economic and geographical position, natural conditions, history of formation, population, economy, improvement.

Conclusions. The strength of the interaction of settlements within the Ivanovo urban agglomeration is not as great as in many other agglomerations of our country. And the reason for this is the proximity of Moscow, which in many ways pulls over the functions of the core. The image of the depressive territory during the expedition was not justified to a large extent. Cities are alive and trying to develop. Some do it better, others worse.