Vol 8, No 2 (2026)

Background: During deep drilling of oil and gas wells, the dynamic instability of the drill string caused by radial and axial vibrations of the drill bit leads to a reduction in the rate of penetration (ROP), increased tool wear, and deterioration of the wellbore gauge. This problem becomes particularly pronounced when drilling formations with alternating lithology and rock strength. An analysis of existing technical solutions, including the roller-cone reamer–stabilizer design described in the Patent of the Republic of Kazakhstan No. 22228 (E21B 10/30), has demonstratedthe need to improve the geometric and dynamic parameters of stabilizing devices intended to ensure stable dynamic equilibrium of the “bit–drill string–rock formation” system.

Aim: The objective of this study is to provide theoretical and experimental justification for the causes of radial vibrations of the drilling system and to develop a near-bit roller-cone reamer–stabilizer capable of ensuring the stability of the bottom-hole assembly (BHA) at the well bottom. The stability is achieved through the efficient arrangement of the working elements at an angle of 120° and by meeting the conditions meeting the conditions for the formation of the roller cones based on their minimum size.

Materials and methods: The study is based on the principles of dynamic systems theory, the laws governing energy dissipation in rotational mechanical systems, and the principle of least action. A mathematical model was developed to establish the relationship of the minimum size of the roller-cone forming elements on the nominal radius of the reamer–stabilizer. The geometric parameters of an experimental prototype of a near-bit stabilizer with a diameter of 269.9 mm, manufactured on the basis from a 203 mm heavy-weight drill pipe (HWDP), were analytically substantiated. Experimental studies were carried out under field conditions during deep drilling operations.

Results: It was established that meeting the structural condition $b_{\min }>\frac{\sqrt{7}\cdot R_{PAC}}{2}$ ensures stable dynamic equilibrium of the drilling tool relative to the wellbore axis. Field tests demonstrated a 5% increase in ROP and a 7.3% increase in bit run length. A reduction in bit balling and clogging was also observed, indicating improved hydrodynamic bottom-hole cleaning.

Conclusion: The developed design of the near-bit roller-cone reamer–stabilizer validates the theoretical provisionsregarding the nature of radial vibrations in drilling dynamic systems and ensures an increase in the efficiencyof deep oil and gas well drilling. The obtained results demonstrate the feasibility of industrial implementation of the proposed technical solution and its effectiveness for application in the design of bottom-hole assembly (BHA) configurations.

Background: Conventional waterflooding typically achieves an oil recovery factor of no more than 35–40%, leaving a significant portion of the oil in place within the pore space of the reservoir rock, where it is retained by capillary forces. The application of chemical enhanced oil recovery methods, particularly Alkaline–Surfactant–Polymer (ASP) flooding, is a promising approach for high-viscosity oil reservoirs, where conventional waterflooding is characterized by a highly unfavorable mobility ratio between the displacing fluid and the oil.

Aim: Systematic laboratory evaluation of ASP flooding effectiveness for the productive horizons of Field X (Western Kazakhstan),, based on real core samples from borehole K-2524, with the development development of recommendations for optimising the chemical slug formulation.

Materials and Methods: The study employed methods such as incoming quality control of commercial surfactant samples, compatibility testing at a specified reservoir temperature over a defined period, phase behaviour screening of lauryl sulfate / sodium hydroxide systems with crude oil from two horizons, and filtration experiments conducted using the PLS-200 petrophysical laboratory setup.

Results: ASP flooding with 0.02% sodium dodecyl sulfate (SDS) + 0.6–0.8% NaOH + 2,500–3,000 ppm hydrolyzed polyacrylamide (HPAM) achieved an incremental oil recovery factor of 19.0–19.2% for the Cretaceous chalk horizon (total RF of 68.5–68.9%) and 17.7% for the Jurassic horizon at 3,000 ppm HPAM. The HPAM concentration is a critical design parameter: deviation from the required mobility ratio condition (M ≤ 1.0) reduces the incremental oil recovery by nearly half.

Conclusion: ASP flooding demonstrated high efficiency for both horizons when the formulation parameters were properly optimized. The optimal formulation (0.02% SDS + 0.8% NaOH + 2,500 ppm HPAM) is recommended as providing the best balance between incremental oil recovery factor and reagent cost.

Amid the digital transformation of the global economy, Big Data analytics and advanced analytics technologies are becoming key tools for enhancing business efficiency and sustainability. Their application is particularly relevant in the capital-intensive and high-risk oil and gas industry, where data-driven decision-making offers significant competitive advantages.

This study examines the opportunities and benefits of implementing Big Data and analytical solutions across various stages of the oil and gas production cycle – from geological exploration and drilling to processing and transportation. The study presents the main data sources and types characteristic of the industry, as well as modern analytical methods, including descriptive, predictive, prescriptive, and real-time analytics. Special attention is given to machine learning and artificial intelligence algorithms used for predicting equipment failures, optimizing drilling parameters, and modeling reservoir behavior.

Based on the analysis of case studies from leading international companies such as BP, Equinor, Gazprom Neft, and others, it is shown how digital tools can improve decision-making accuracy, reduce operational costs, and minimize technological risks. The study also examines the key challenges hindering the widespread adoption of Big Data in the sector, including a shortage of qualified personnel, integration difficulties between legacy and modern systems, cybersecurity concerns, and the high cost of digital transformation.

The analysis leads to the conclusion that data and analytics constitute strategic assets for the future development of the oil and gas industry. Digital technologies open up new horizons in forecasting, management, and sustainable production, paving the way for next-generation intelligent oil and gas enterprises.

Background: Correct identification of the fluid phase state (oil or gas condensate) at the Eastern Urikhtau field is critically important for reliable reserve estimation and the selection of an appropriate development strategy. Anomalously highgas-oil ratio values in wells EU-6 and EU-7 (up to 1000 m³/m³) as well asdiscrepancies between the hypsometric levels of the presumed gas-oil contact and regional data, create uncertainty that requires resolution using an integrated approach.

Aim: To determine the genetic origin and phase state of reservoir hydrocarbon systems at the Eastern Urikhtau field based on data from seven wells using a multidisciplinary approach.

Materials and methods: The study was based on seven bottomhole fluid samples collected from wells EU-1–EU-4 and EU-6–EU-8. The analytical program included gas chromatography (GC), gas chromatography–mass spectrometry (GC-MS), fingerprinting, biomarker analysis (steranes, terpanes, aromatic hydrocarbons), as well as physicochemical and PVT analyses using the FLUID EVAL™system with visual phase-statemonitoring.

Results: Biomarker analysis confirmed the genetic uniformity of all samples. indicating that the fluids were generated within a single marine carbonate petroleum system. Based on a set of criteria (density >780 kg/m³, molecular weight >150 g/mol, C₇₊ content >85%, Σ(C₁–C₉)/Σ(C₁₀₊) ratio <1), all samples were classified as oil. The sample from well EU-7 was identified as volatile oil. PVT analyses and visual observations ruled out the presence of gas-condensate systems. The established phase model corresponds to an oil reservoir characterized by gravitational segregation and a volatile-oil transition zone in the crestal part of the structure, without a conventional gas cap.

Conclusion: The multidisciplinary approach applied in this study enabled verification of the fluid phase zonation at the Eastern Urikhtau field. The proposed reservoir model, representing an oil rim without a distinct gas cap, requires the application of the volumetric method for reserve estimation and consideration of the identified phase heterogeneity during field development planning in order to minimize geological risks and ensure accurate resource assessment.

Background: High water cut increases operating costs and reduces oil recovery. Gravity-driven redistribution of oil and water during well shut-in periods has been proposed for reducing water cut; however, laboratory methodologies for investigating this phenomenon in core samples remain limited.

Aim: To develop a laboratory methodology for evaluating gravity segregation in oil–water saturated cores under controlled conditions.

Materials and methods: The methodology is based on epoxy-sealed cores fixed inside a sleeve, providing a practical and cost-effective core holder capable of accommodating pressure ports. Two experimental scenarios are considered: early water breakthrough caused by an unfavorable mobility ratio, and breakthrough induced by a high-permeability channel. After water breakthrough, flooding is suspended, the core is aged in a vertical position, and water injection is subsequently resumed. Effluent analysis is performed using a gravimetric oil–water separation technique based on the adhesion of oil to polyethylene. The methodology enables qualitative and quantitative assessment of fluid redistribution caused by gravity.

Results: Fractional flow analysis demonstrates that, when viscous oils are used, a significant fraction of mobile oil remains in the core after water breakthrough, whereas artificial high-permeability channels can be used to preserve low-viscosity mobile oil within the matrix for subsequent redistribution by gravity segregation.

Conclusion: The developed methodology provides a reliable and inexpensive platform for investigating gravity segregation in cores and may support the development of field technologies aimed at reducing water cut and improving oil recovery.

The gradual tightening of environmental standards, combined with growing global demand for environmentally friendly fuels, has significantly increased the importance of advanced technologies in oil refining. In this context, the catalytic isomerization of light alkanes (C₄–C₆ fraction) is one of the most strategic processes for improving gasoline quality without increasing the concentration of aromatic hydrocarbons or adding hazardous additives. From a chemical standpoint, this process promotes the structural rearrangement of linear paraffins into corresponding branched isomers, which possess a higher octane numbers. This results in a significant improvement in the fuel’s combustion characteristics, while reducing the formation of environmentally harmful emissions.

This review systematically examines the fundamental principles underlying the isomerization of alkanes. Particular attention is given to the reaction mechanism, which proceeds via carbocationic intermediates at acidic catalytic sites, reflecting the well-established mechanism of acid-catalyzed hydrocarbon transformations. Furthermore, the thermodynamic constraints governing the equilibrium distribution of isomers, as well as the kinetic factors influencingreaction rate, product selectivity, and overall process efficiency, are critically analyzed. Special emphasis is placed on bifunctional catalytic systems combining metal and acid functions, enabling the simultaneous hydrogenation–dehydrogenation and skeletal isomerization steps. The role of competing side reactions, notably hydrocracking and aromatization, is also addressed due to their influence on product yield and catalyst stability.

Beyond theoretical considerations, this review examines the complexities inherent in real industrial systems. In practice, the attainment of thermodynamic equilibrium is often limited by kinetic constraints, resistance to mass transfer within particles and between phases, as well as by the gradual deactivation of the catalyst due to coke formation or poisoning. These factors require a more detailed understanding of process behavior under industrial operating condition.

Having committed in 2023 to reducing methane emissions by 30% by 2030, Kazakhstan plans to update its legislation on this greenhouse gas, focusing on improving its emission monitoring, reporting, and verification systems for emissions, using the example of subsidiaries and affiliates of NC KazMunayGas JSC. In the context of sustainable development and climate change mitigation, accurate measurement and transparent reporting of methane emissions are becoming key elements of effective environmental policy.

The article provides an overview of approaches to calculating methane emissions based on the national methodology and in accordance with the requirements of OGMP 2.0, organized by UNEP. The implementation of this article is necessary not only to meet national and corporate commitments, as exemplified by NC KazMunayGas JSC , but also in connection with the entry into force of the new European Union regulation on methane emission reduction.

The data on methane emissions for the KMG group of companies for 2023 and 2024 are presented, calculated using the national methodology and OGMP 2.0. The measures required to fulfill international commitments and improve the accuracy of methane emissions accounting in the oil and gas industry are outlined. Key areas for improving national regulation of methane emissions in the oil and gas industry have been identified.