Managing produced water has become an increasingly important issue in Western Siberia and other oil-producing regions worldwide. The rising water content in oil production makes effective water handling and disposal more crucial than ever. This study aims to analyze changes in the hydrogeochemical conditions of the Aptian-Albian-Cenomanian hydrogeological complex at an oil field in the Alexandrovsky petroleum district of the Vasyugan petroleum province. For many years, this complex has served both as a source of reservoir water and as a disposal interval for excess produced water. The authors analyzed the geological structure and hydrogeological setting of the field, summarized production and water disposal data, and evaluated long-term changes in groundwater chemistry. This article uses hydrogeochemical monitoring data from 70 reservoir water samples. The results confirm that the reservoir waters have generally maintained characteristic hydrochemical composition. At the same time, the concentration of suspended solids has increased, and elevated levels of petroleum hydrocarbons have been intermittently recorded. These results point to the need for continued improvement of groundwater monitoring practices.

The atlum aquifer is used for drinking and domestic water supply at the Khugot freshwater This study is motivated by the need to monitor groundwater quality in the Khugot field intended for drinking and domestic water supply. The long-term operation of the water intake can alter the geochemical composition of the Atlym aquifer water. The aim of this article is to evaluate both the temporal and spatial changes in groundwater composition and identify the factors of its transformation. The objectives include comparing the major ion composition of water samples collected during the development stage with those from current operating period, classifying water types using the Piper diagram, and identifying patterns of ionic composition changes and associated processes. The main method is hydrogeochemical analysis of groundwater samples combined with the interpretations from the Piper diagram. The results show a shift in the prevailing groundwater type. The proportion of samples dominated by sulfate ions increased from 17 % to 100 %, leading to the establishment of a sulfate sodium type; the cation composition (calcium, magnesium) remained stable. Additionally, ongoing gypsum precipitation is diagnosed. The obtained data can be used to optimize groundwater intake operation, predict groundwater quality, and contribute to the development of effective groundwater protection measures. This is where the practical value of the study lies.

Prospecting and exploration of uncounted resources is one of the key challenge for the oil and gas industry, requiring optimal allocation of budgetary funds. This article aims to enhance the reliability of reserve estimates while reducing investment compared with traditional exploratory drilling methods, by using a probabilistic model in constructing three-dimensional geological models. The authors developed probabilistic models for the studied fields using porosity and permeability data obtained from core samples. The methodology includes an original approximation techniques and interpolation of data based on stochastic distributions to update well-log curves and estimate reservoir properties under probabilistic conditions. The researchers calculated hydrocarbon reserves for both the original and the probabilistic geological models using the volumetric method. Next, they compared the total oil reserves obtained from the probabilistic models with those calculated from the original models. To evaluate the spatial distribution of the differences, authors compared linear reserve map generated by the probabilistic and conventional approaches. The proposed methodology enhances the accuracy of estimating uncounted geological reserves, reduces the need for additional exploration drilling, and supports more efficient field development planning, particularly under budgetary constraints.

This study examines the porosity and permeability of productive carbonate reservoirs in the Nasiriyah oil field in southern Iraq. The authors compare the petrophysical properties of the reservoirs to identify the most favorable conditions for hydrocarbon production and to determine the most productive intervals. The results can help to optimize field development, justify priority drilling zones, and improve hydrocarbon recovery. This study has highly relevant to the oil and gas industry. It provides a basis for accurately assessing reservoir potential and guides effective field development planning. The study uses geophysical data from five production wells (NS-1–NS-5). Researchers applied comparative analysis of the spatial distribution of porosity permeability, and and net pay thickness within the productive reservoirs. Researchers applied statistical analysis and spatial interpolation methods. This approach enabled them to map key reservoir properties and delineate their lateral The results show a strong contrast between the two studied reservoirs. One reservoir has higher porosity (20–23%) and permeability (131–412 mD), whereas the second has lower values, with porosity of 12–15% and permeability of 2–6 mD. The spatial distribution of reservoir thickness and petrophysical properties has a dome-shaped pattern, with the highest values in the central part of the field. This pattern reflects the Cretaceous depositional conditions and subsequent diagenetic processes. The eastern part of the field shows poorer reservoir properties because of changes in lithology and deterioration of pore structure. The results confirm the high heterogeneity of the carbonate reservoirs and agree with published data from similar fields in southern Iraq. This study has important practical significance. The results can assist in identifying priority areas for new wells, optimizing field development systems, and enhancing geological and reservoir models.

Well killing is a complex process that requires accurate technical and mathematical approaches. The well killing process impacts well production performance. This article examines well-killing operations to enhance our understanding of the processes occurring within a well. We describe the design and test results of the mobile software and hardware well killing complex (MPAK GS). MPAK GS is capable of simulating fluid injection through the annular and tubing sections and can replicate well-killing operations using both forward and reverse circulation. This setup enables visual monitoring of each stage of the process inside the model well. We recorded the obtained data in digital form and used them to establish mathematical relationships between pressure measurements at various points in the well and the operating parameters. The obtained and proven dependencies can be used to develop a mathematical model of the hydraulic wellkilling program.

Complex carbonate reservoirs of Eastern Siberia are highly heterogeneous and difficult to predict seismically because of intrusive bodies, thin-bedded strata, and salinization zones. This study aims to evaluate the effectiveness of an integrated reservoir geometrization approach for refining the boundaries of productive zones, improving production drilling success, and reducing geological risks using an oil and gas condensate field in the Irkutsk Region as a case study. The leading method is a retrospective analysis by integrating long-term well testing, interference testing, numerical 2D flow modeling in Kappa Ecrin Saphir, seismic attribute maps (acoustic impedance and Vp/Vs ratio), and seismic facies analysis. The results show that the productive reservoir is only partly associated with basement highs and does not fully conform to their boundaries. By combining dynamic reservoir data with seismic information, the authors define the lateral extent of vuggy porosity zones more accurately. Initial rates, reservoir pressure measurements, and pulse interference tests confirm authors' results. This approach can enhance drilling success from 78,4 % to 86,4 % and provides an effective tool for optimizing well placement and development programs.

Bit balling remains a significant challenge in drilling, particularly in the oil fields of Western Siberia (Khanty-Mansi and Yamalo-Nenets Autonomous Okrugs). This problem is especially critical within the highly plastic clayey deposits of the Bazhenov and Kuznetsk formations, where tradional methods are ineffective. Analysis of field data from 2024 revealed that bit balling caused economic losses of 4.7 billion rubles. Notably, 34% of all tool sticking events are associated with clay cuttings adhesion. This article aims to systematize the causes of bit balling, evaluate the performance of new chemical additives for its prevention, and develop an integrated approach to drilling parameter control in order to minimize the risk of drilling complications. The study relies on an analysis of 2024 field data as well as laboratory and field testing of three new classes of chemical additives. These classes include a nanostructured inhibitor based on modified organosilicate (OSI-2024), a hybrid inhibitor containing graphene nanoplatelets (GNP-Inhibitor), and an anti-adhesion formulation based on fluorinated polymers (PTFE-complex). The study demonstrates that OSI-2024 reduces the adhesive strength between clay and metal by 68 % and decreases the thickness of the adhered clay layer by 74% compared with conventional formulations. GNPInhibitor shows 91% of its inhibitive performance at temperatures up to 135°C. PTFE-complex shows high efficiency when drilling through highly adhesive gumbo clays at high rates of penetration. The overall economic effect of implementing the additives exceeds their cost by a factor of 4.7. These innovative chemicals and operational recommendations provide a comprehensive approach to reducing drill string sticking, optimizing drilling performance, and improving field development efficiency. Thus, they demonstrate strong potential for industrial application.

This article explores approaches for optimizing the performance of the reformate stabilizer within a catalytic reforming unit. This study aims to minimize the loss of gasoline-range hydrocarbons in the distillate while ensuring the required quality of the final product, stable reformate. The authors modeled the stabilization process in Aspen HYSYS and evaluated the influence of the main parameters: reflux rate, column temperature profile, and possible design modifications on product quality. The researchers also performed a hydraulic analysis and determined the hydraulic capacity limit of the column. The study demonstrates how the key product specifications change under different operating conditions. Authors also evaluate the additional operating costs associated with higher reflux rates. The article considers an increase in the number of trays and the replacement of trays with packings. The authors analyzed several options to ensure product quality. To limit high-boiling hydrocarbons in the distillate and control the Reid Vapor Pressure of the reformate, they suggest two solutions. The first solution involves optimizing the temperature regime in the lower part of the column. The second solution requires replacing the trays with structured packed beds.

Western Siberia is an important oil-producing region of the Russian Federation, with current oil reserves estimated at approximately 4.88 billion tons. In recent years, annual oil production has declined due to a deteriorating resource base and increasing water cut. Water now accounts for about 90% of the total fluid produced from oil wells. In this regard, it is important to develop and evaluate new enhanced oil recovery methods. This article examines cyclic waterflooding as an enhanced oil recovery method for layered oil reservoirs. The author develops a synthetic two-dimensional, two-phase model of a multilayer reservoir with low-permeability barriers between the layers. This work aims to determine how cyclic water injection impacts the distribution of oil saturation in multilayer reservoirs. The author calculates the incremental oil production, ΔQ, for different numbers and arrangements of layers with different permeability. The researcher then compares several development scenarios using numerical simulation. The results show that cyclic waterflooding can provide substantially different incremental oil production depending on the arrangement of highand low-permeability layers. These results can help identify reservoir intervals with the greatest potential for incremental oil production and support the design of cyclic waterflooding programs. The article identifies three reservoir types based on layer arrangement. The first type has low-permeability layers above high-permeability layers. The second type has high-permeability layers above low-permeability layers. The third type consists of interlayered highand low-permeability units. Increasing the degree of layering, denoted as Kr, reduces the efficiency of cyclic waterflooding in the first and second types. For the third type, cyclic waterflooding becomes more effective when the low-permeability layers form a continuous unit. Mixing layers with different permeability tends to decrease the incremental oil production from cyclic waterflooding. The highest efficiency occurs at Kr=2.

The oil-and-gas fields of the Volga-Ural basin have been developed for many decades. Nevertheless, the region still contains significant hydrocarbon reserves in carbonate formations. However, the low permeability and thin oil-bearing intervals prevent their cost-effective development. This article presents a comprehensive approach for designing development systems for such reserves, using the Orenburg oil and gas condensate field as an example. Conventional development planning method designed for terrigenous reservoir is often ineffective for complex reservoir, necessitating a revision of the method. This work focuses on identifying reservoir types by using all available data, including core, seismic, well logging, and well testing data, along with modern seismic processing techniques. By gaining a deeper understanding of the reservoir types and their spatial distribution, the author can select the most effective development strategies, including well design and stimulation methods, at the early stages of field development. The proposed comprehensive approach improves the economic performance of developing hard-to-recover reserves by up to 20% through increased production rates during the early stages of field development.

Gas gathering systems are complex and dynamic production networks. As a gas condensate field develops, operating conditions change continuously. Factors such as pressure, temperature, and flow rate vary at the inlet of the gathering system, while modifications in gas processing facilities and the commissioning of booster compressor stations affect outlet conditions. Therefore, an urgent task is to optimize the modes or characteristics of the gathering system to increase its throughput. This work presents a nodal analysis approach for optimizing the operation of a gas condensate field gathering system. This approach identifies system bottlenecks and selects the most effective measures for starting wells and additional pipeline sections. By applying this approach, the authors suggest solving the flow allocation problem for a hydrocarbon production system by considering operational constraints and a large amount of integer variables (pipeline looping, well start-up, and switching wells or pipelines among processing facilities). The authors validate the approach on a section of a gas condensate field gathering system. The study determines the configuration of the most effective operations to significantly increase both daily gas and condensate production. This methodology achieves 75 % of the maximum production potential available through full implementation of all development options. Notably, it required pipeline looping along only 40 % of the candidate pipeline sections and brought only half of the available additional wells into production. The project requires looping just 40 % of the candidate pipeline sections and brought only half of the available additional wells into production.

This article deals with the development of a hybrid methodology for geotechnical monitoring of buildings and structures operating in permafrost zone. This approach combines in-situ measurements using a wide range of equipment and numer-ical modeling within a single information system. This work describes a principle for accumulating measurement data obtained from various sources using various methods and appropriate equipment. The authors of this article classify the data by type, with accumulation in a unified interpreter database. This database serves as a foundation for developing digital twins of monitored facilities using mathematical models. Combining monitoring processes with the processing of measurement results in numerical software packages enhances the accuracy in assessing the stress-strain state of structures and facilitates a more reliable evaluation of data sufficiency. The result of this work is a concept, the successful technical implementation of which will enable identifying critical zones, detecting deviations from design and regulatory requirements, and generating recommendations for ensuring the operational safety of the monitored facilities.