Today, the study of the Berezovskaya formation is a relevant task, since the search and confirmation of new gas sources will replenish the resource base and maintain the planned production capacity. The article provides a comprehensive analysis of the hydrocarbon resource potential of the Upper Cretaceous deposits of the Berezovskaya formation. The analysis was focused on the regional structure of the area, i.e. paleogeographic environments of the Upper Cretaceous interval formation, structural traps distribution within the interval. In addition, the thickness and paleorelief maps of the Lower Berezovskaya subformation were examined. The main features of the studied area, as well as the challenges faced within the interval, such as the high content of clay minerals swelling when in contact with water, low permeability, and lithological and mineralogical heterogeneity, were identified. The data obtained from well logging indicate that the NB1 reservoir interval of the Lower Berezovskaya subformation is characterized by high productivity within the studied area. Therefore, a detailed assessment of the resources and production potential has been initiated. Based on the results of the study, the prospects of the studied interval have been evaluated, and the potential of promising targets within NB1 reservoir has been assessed.

The fluid model of a field frequently becomes more complex during the exploration improvement. When developing a 3D model, it is necessary to take into account all available geological information without losing the quality and speed of model update. Based on Turonian hydrocarbon deposits, the methods of geometrization of a reservoir producing part are described in detail, particularly, with tectonic or lithologic shields, by using non-horizontal surfaces and additional structural borders or by separating deposits blocks with different fluid contacts. The benefits and concerns of using these methods in the 3D geological model update and the certainty of their geological substantiation are analyzed. The best method to modify the field model, which is consistent with concept of the reservoir geological structure, is selected.

On the periphery of the West Siberian Basin, up to 30 % of J_2-4 reservoirs within the Malyshev horizon of the Tyumen formation cannot be predicted correctly. The reasons include the low exploration degree of the territories by deep wells, which is why the net reservoirs are predicted based on 3D seismic data, and poor seismic resolution against the size of traps in the Tyumen formation. The article presents a case study of the application of geological and geophysical, seismic materials related to the Uvat area in the south of Tyumen region. The aim is to describe the lessons learned when addressing the reservoir forecasting issue associated with one of the Tyumen formation reservoirs (J₂) of complex (coastal-transitional and continental) genesis. The article describes the technologies applied by the Tyumen Petroleum Research Center LLC to estimate net pays based on 3D seismic data. A complex of main geological and seismic factors that control the forecasts of thin terrigenous reservoirs based on seismic data is considered. These include the structure of the J₂ unit (vertical features of net reservoir evolution), the effect of carbon content, the issues of separating net-reservoir and non-reservoir rock by petroelastic properties, etc. The results of the analysis presented in this article are employed actively in the context of geological exploration and the identification of priority traps in the Tyumen formation within the territory of the Uvat project.

In the modern world, in large fields with extensive gas caps, oil rim development is associated with the issue of gas breaking through from gas caps to the bottom of oil wells. Furthermore, this issue may also be aggravated by the limited capacity of associated petroleum gas disposal and/or transportation infrastructure. The article presents an analysis of the evolution of methodologies aimed at reducing the production of breakthrough gas from a gas cap by oil wells during the development of an oil rim of the Bt reservoir of the Botuobinsky horizon of the Srednebotuobinskoye oil and gas condensate field. To date, an effective strategy for the development of the under-gas-cap zone has been formulated, comprising the implementation of diverse technologies with the objective of reducing the gas-oil ratio. The experience of developing the under-gas-cap zone of the Srednebotuobinskoye oil and gas condensate field may prove instructive in the development of analogous fields exhibiting comparable geological characteristics.

The Upper Cretaceous, potentially gas-bearing gaizes of the Hayakha formation (Santon) of the West Siberian Plate, which covers an area of approximately 2.5 million km², is characterized by a highly irregular degree of crystallization of silica aggregate (opal-cristobalite-tridimite or OCT-phase). This is an important parameter for assessing filtration-capacity properties. The gaize is present in 20-30 m thick strata and is distributed across an area of approximately 2.5 million km². The crystallization of the OCT-phase (ageing) in natural systems can be attributed to a number of factors. The study of the transformation features of the Upper Cretaceous gaize rocks currently necessitates a unified and systematic approach. A series of laboratory techniques, including petrographic description of transparent slides, X-ray diffraction analysis of the total (XRD) and fine fraction (XRD_clay), and scanning electron microscope, were employed to evaluate the extent of opaque aging in cores from over 30 wells. In most of the West Siberian Plate within the Hayakha formation gaizes the quartz content, according to XRD data, ranges from 5-10 to 30-45 %. Additionally, the proportion of OCT-phase is observed to be 30-50 %. However, in the western and south-western regions of the West Siberian plate, quartz constitutes up to 80 % or more, and OCT-phase is undetected by the XRD method. The morphological differences of silica isolations are established on scanning electron microscope images at a magnification of 5,000-6,000 times. In the examined stratigraphic sequences, the areas of rocks exhibiting an elevated degree of OCT-phase ageing do not correlate with the areas displaying indications of transformation of swelling clay minerals (montmorillonite) into illite. On the basis of the accumulated new data, as well as taking into account the mid-Maastrichtian incised relief forms (channels) detected on seismic sections in the western part of the West Siberian Plate, the following conclusion is made: the absence of OCT-phase and anomalously high quartz fraction in gaizes of the Hayakha formation in the western region of the West Siberian Plate are caused by complete crystallization of OCT-phase in the conditions of subaerial exposure (exogenous conditions) of Upper Cretaceous sediments in the Middle Maastrichtian.

In the analysis of the development of an oil field, all available geological and field information is employed. Given the constant interaction and coexistence of oil and water, it is evident that hydrogeological information, particularly its evolution throughout the process of oil field development, should exert a significant influence on the analysis outcomes. This article considers the potential of hydrogeological information as a means of enhancing our understanding of an oil deposit. An attempt is made t to classify this information. The effect of disparate hydrogeological information on particular decision-making processes is determined. It is observed that the most valuable hydrogeological information can be obtained exclusively during the drilling of an oil field. It is recommended that qualitative initial hydrogeological information on the location and movement of boundary and bottom waters of an oil field be used to create adaptive waterflooding systems. The proposal to establish a set of normative regulations governing the process of obtaining and utilizing hydrogeological information at all stages, from initial prospecting and exploration to the development of oil fields, has gained significant support.

Relocation of the main capacities of oil production infrastructure from Central to Northern Russia necessitated a re-evaluation of oilfield development strategies, particularly addressing the challenges of constructing foundations for pipelines, processing facilities, and power plants. These foundations are formed by drill-dipping piles into pre-drilled boreholes. The use of drill dipping piles in permafrost is technologically essential as alternative pile types are impractical. The most common are drill dipping piles fabricated from longitudinal seam pipes welded with high frequency current techniques (as per GOST 20295 and GOST R 58064). Performance of such pipes in permafrost conditions was evaluated through laboratory simulations mimicking operational conditions, as well as in-situ at the test site of Federal Research Centre "The Yakut Scientific Centre of the Siberian Branch of the Russian Academy of Sciences" where full-size piles were installed in firm loamy and wet peaty permafrost soils. Pipes both with and without post-weld heat treatment, as specified in SP 16.13330.2017, were tested. The authors examined static mechanical properties and impact toughness of the base metal and welded joints of the pipes, as well as corrosion resistance and crack resistance. The research revealed that post-weld heat treatment did not significantly enhance the reliability of drill dipping piles fabricated from 09G2S steel. Concurrently, microstructure analysis of the welded joints revealed a considerable number of defects along the weld-fusion line, potentially accelerating pile failure.

Solving the world-class problem of reducing greenhouse gas emissions into the atmosphere and potential utilization of carbon dioxide (CO₂), the article provides an overview of technologies for injecting CO₂ into the oil and gas reservoirs to enhance oil recovery and stimulate oil production. Two main methods of carbon dioxide (CO₂) injection are proposed and described in detail. These are the Huff and Puff method, which involves the injection of CO₂ into production wells, and CO₂ injection into injection wells.
The technology of injecting carbon dioxide into production wells has a number of advantages, such as the lack of capital costs and low operating costs, quick effect manifested in increased oil rates and efficient use of CO₂. The general principle of the technology is the controlled supply of carbon dioxide through the mouth of a shut-in production well into the bottomhole formation zone. The efficiency of the technology is achieved primarily through the reduction of oil viscosity and volumetric expansion of oil, the decrease of interfacial tension, and the reduction of relative phase permeability by water. Consequently, residual oil saturation is reduced by the increase in the amount of trapped gas.
The second technology for injecting carbon dioxide into injection wells to achieve a positive technological effect requires a larger volume of injection agent and a longer period for evaluation of the effect. The efficiency of the technology and the increase in the oil displacement ratio are achieved through the distribution of large volumes of injected carbon dioxide through low-permeability reservoir channels and involvement of residual oil.
The article presents the necessary conditions and main stages of CO₂ injection process organization using the proposed technologies, and describes the composition of the required equipment. Special attention is paid to the necessity of using inhibitors to protect downhole equipment, as well as to the selection of suitable inhibitors, taking into account their physical and chemical characteristics, compatibility with other reagents and reservoir properties. The authors of the article have conducted an expert survey of the market for the availability of specialized equipment in Russia and the services of domestic manufacturers in the field of gas injection technologies.
The conclusion of the article highlights the importance of CO₂ injection careful planning and monitoring, as well as the potential of gas-enhanced methods to improve production and reduce environmental impact.

The current state of oil production is characterized by a decline in the proportion of reserves located in conventional reservoirs. The development of complex and highly complex reservoirs is becoming increasingly important. A significant proportion of oil reserves are concentrated in low-permeability reservoirs that are no longer economically viable to develop using traditional field methods. The aim of the work is to create a predictive tool for the selection of optimal parameters of the development system using horizontal wells and multistage hydraulic fracturing of reservoirs. To solve this problem, a fully connected neural network model was trained that predicts the parameters of the production profile as a function of the initial geological and physical conditions and the parameters of the development system. The architecture of the resulting neural network includes 3 linear layers of 300 neurons each. The training sample for the model was the results of multivariate calculations on a synthetic hydrodynamic model simulating the operation of a development element using a horizontal well with multistage hydraulic fracturing in depletion mode. The developed model can be useful in solving the problem of designing a development system in new or undrilled areas of low-permeability oil fields.

Application of organic solvents for removal of asphalt-tar-paraffin deposits is one of the most widespread methods in technological processes of production, transportation, storage and processing of high-resin oils. In spite of certain results, the problem of directional solvent selection taking into account the nature of oil and asphalt-tar-paraffin deposits in specific conditions is far from being solved. The aim of the article is to test the hypothesis of the relationship between the solubility of asphaltenes and their average electron affinity and solvent ionization energy. Using the solubility isotherm of asphaltenes in non-ionogenic solvents, the solubility of West Siberian oil asphaltene samples and model fragments was evaluated. The studies have shown that asphaltenes with high effective electron affinity have the maximum solubility. Solvents with low ionization potential have the highest solubility, which confirms the thermodynamics of solubility through the formation of donor-acceptor complexes. The performed studies will help field specialists and engineers of service companies in scientifically justified selection of solvent depending on the type of deposits of heavy components of oil.

Determining the mechanisms of deformation distortion and softening processes of near-surface layers in alloys, including high-entropy alloys, is one of the priority tasks in modern materials science. Interest in such studies, which require an integrated approach to determining the relationship between accumulated structural distortions and softening processes, is due to the great potential for the use of these alloys in the new generation of nuclear power. In order to assess the resistance of alloys based on NbTi, NbTiV, NbTiVZr compounds to the accumulation of radiation damage, irradiation experiments were carried out at the DC-60 accelerator, taking into account the capabilities of modeling radiation damage, both in the case of single (isolated) areas of damage, and when overlap. The obtained results of the dependences of changes in the structural parameters of the alloys under study depending on the number of components for irradiated samples are direct confirmation of the influence of differences in atomic radii on the resistance to deformation tension during the accumulation of radiation damage. It was found that the NbTiVZr alloy exhibits the smallest structural changes caused by irradiation, which indicates high resistance to deformation distortion and a decrease in strength properties and wear resistance. It has been determined that the main mechanism influencing the loss of wear resistance during tribological friction tests is the deformation distortion of the damaged layer, the magnitude of which determines the degradation of the near-surface layer of the alloys.