Kazakhstan journal for oil & gas industry

Background: Horizontal well drilling in geologically complex environments is inherently uncertain. These uncertainties stem from variability in formation properties, structural discontinuities, and limitations in data interpretation. Reaching project targets effectively requires the adoption of modern uncertainty management techniques.

Aim: First, analyze and summarize the practical experience of KMG Engineering’s Remote Drilling Support Service in managing uncertainty during horizontal well drilling; and second, demonstrate how an integrated approach can improve the reliability and cost-effectiveness of oil and gas field development.

Materials and methods: The study identifies the main sources of uncertainty encountered during drilling and reviews methods for their mitigation, including real-time monitoring, geosteering using a stratigraphic method, seismic modeling, and resistivity inversion. It describes the use of advanced MWD/LWD tools, remote formation boundary detection technologies, and data integration systems. Field experience is also presented regarding the application of Solo Box backup data storage systems and artificial intelligence technologies for autonomous geosteering.

Results: Field experience demonstrates that the integrated use of advanced technologies enables engineers to quickly identify discrepancies between model expectations and real-time drilling data, make timely trajectory adjustments, and keep wellbore within the productive zone. As a result, this approach reduces operational risks, improves well construction quality, and supports the consistent achievement of project objectives.

Conclusion: An integrated approach to uncertainty management that combines real-time monitoring, geosteering, data analysis, and the innovative technologies significantly improves the efficiency of horizontal well drilling under complex geological conditions. Such an approach is recommended to increase both the reliability and cost-effectiveness of oil and gas field development.

Background: This study addresses the need to refine the block structure of the Triassic sequence in the Zhetybay South field, with a focus on the hydrocarbon productivity of the T₂V horizon, which is associated with Middle Triassic deposits. By integrating legacy geological and geophysical data with modern 3D seismic survey results, the analysis provides an updated interpretation of the structural framework and highlights the exploration potential of the target interval.

Aim: This paper investigates the geological framework and hydrocarbon potential of the Triassic succession in the Zhetybay South field. Drawing on both legacy and recent data—from exploratory and production wells to 3D seismic surveys – the study synthesizes results from four reserve estimation campaigns conducted in 1972, 1983, 2010, and 2023. Particular emphasis is placed on reassessing the productivity of the T₂V horizon.

Materials and methods: The primary data sources include well testing and perforation results, along with 3D seismic surveys conducted at the field in recent years.

Results: The structure of the Triassic sequence has been refined, including the reflective horizon T₁o_bot, which hosts the T₁V accumulation. The presence of a potential oil and gas condensate accumulation within the T₂V horizon has been identified and confirmed by testing results from productive intervals.

Conclusion: The integration of new 3D seismic data has enabled the revision of structural maps, clarification of the T₁V accumulation’s structural setting, and identification of a block-faulted framework. In the Nоrmaul Arch area, additional 3D seismic acquisition is recommended to improve fault mapping. A structural map of the T₂V horizon has also been developed, providing further support for its productivity. Since reservoir contacts are currently assumed, delineation of the accumulation’s potential extent remains necessary. Following these efforts, an operational reserve estimation for the T₂V horizon is recommended.

Background: Polymer flooding is one of the most commonly used methods in enhanced oil recovery, but polymer solutions are exposed to various physico-chemical factors that can significantly reduce their performance. This study examines the comparative strength of crosslinked polymer gels applied in EOR operations at the Uzen field.

Aim: Comparison of polymer gel strength using marine and Alb-Cenomanian waters to support more effective EOR operations.

Materials and methods: The experiments used Alb-Cenomanian and marine waters collected directly from the Uzen field. This helped closely replicate real reservoir conditions. Distilled water was also used for comparison. The chemical reagents matched those currently applied in EOR projects at the same field. All working solutions were prepared using high-precision laboratory equipment, following procedures standardized by the American Petroleum Institute (API).

Results: Laboratory tests demonstrated that gel systems based on Alb-Cenomanian water exhibited greater strength and thermal stability compared to those prepared using marine water.

Conclusion: The study looked at how water salinity affects the viscosity of polymer solutions. It also included gel strength tests under different conditions and explored the factors influencing gel performance. The findings may help improve EOR methods and reduce the negative effects of polymer-based technologies.

The article presents the known technological causes of the overflow of the water-gas mixture and reservoir fluid in the behind-the-casing space of a cemented oil and gas well and through a cement plug, and the complications to which they can lead.

Continuous work to improve well abandonment technology allowed Wellbore Integrity Solutions to create a highly efficient ProMILL™ system in 2016. The ProMILL system combines a Bridge Plug assembly, a Section Mill, and a high-ratio Underreamer to prepare the foundation for a cement barrier in a single run. During the milling and expansion process, it eradicates all leak paths from the cement fill, while achieving continuous, reliable rock-to-rock zonal isolation.

Was presented the results of the successful execution of the First ProMILL Job in Kazakhstan onshore - successful deployment of the 5500 ProMILL for high-grade section milling and outer casing ID scraping in one trip.

Artificial intelligence is rapidly gaining ground in the oil and gas industry, driven by the need to improve the efficiency of reservoir development and streamline production operations. One of the most promising applications of AI is the analysis of data collected by downhole monitoring systems – particularly those designed to measure bottomhole pressure. As more permanent downhole gauges are deployed across the industry, operators now have access to continuous, real-time insight into reservoir pressure behavior. The widespread use of permanent downhole pressure gauges enables continuous, real-time data collection on reservoir pressure dynamics. As part of a broader big data environment, these data sets require modern architectures for storage, processing and analysis. By applying machine learning algorithms – such as neural networks and regression models – engineers can uncover hidden patterns, predict reservoir parameters, perform transient pressure analysis without shutting down wells, and improve real-time decision making in field operations. This paper reviews the design principles of pressure monitoring systems and examines modern big data architectures, including lambda, kappa and unified frameworks. It also highlights practical applications of machine learning algorithms using both field data and synthetic datasets. The paper demonstrates the effectiveness of combining proxy modelling with machine learning to assess inter-well connectivity and predict production behavior. The discussion is based on real-world case studies from international and Kazakh oil fields, including the use of CRMP-based digital solutions and ensemble modelling approaches.

Background: Carbonate rocks form subsalt hydrocarbon reservoirs in the Northwestern Margin Zone of the Pre-Caspian Basin. In this context, identifying and analyzing the causes of epigenetic alterations affecting the reservoir properties of carbonate formations is of particular importance, as these alterations influence the optimization of the hydrocarbon exploration and production. These factors underscore the scientific and practical relevance of the present study.

Aim: To identify the causes of alteration and to quantitatively assess the reservoir properties of carbonate formations affected by secondary epigenetic transformations.

Materials and methods: This study investigates subsalt carbonate reservoirs from oil and gas fields in the Northwestern Margin Zone of the Pre-Caspian Basin. The analysis involved both macroscopic and microscopic examination techniques, supported by a range of laboratory tools, including thermal analyzers, thermogravimetric instruments, and X-ray diffractometry. The method proposed in this paper relies on DTA data obtained during dynamic heating of dolomite, calcite and magnesite, focusing on their thermal decomposition behavior. Mineralogical and compositional control of the reservoir formations was carried out using X-ray phase analysis.

Results: A thermal analysis–based technique was developed to quantify secondary calcite in carbonate reservoir formations from subsalt oil and gas fields in the Northwestern Margin Zone of the Pre-Caspian petroleum province. Thermal parameters associated with epigenetic transformations of the dolomite–calcite assemblage was established using representative carbonate samples. These transformations are characterized by the infilling of pore spaces with secondary minerals, leading to reduced porosity and permeability in the affected reservoirs.

Conclusion: Accounting for the structural properties of sedimentary rocks described in this study can significantly improve the quality of hydrocarbon exploration. The proposed method provides detailed information on the mineral composition of the reservoir, their filtration-capacity characteristics of carbonate minerals, the crystallinity of their components, lattice properties, and the physical behavior of magnesium, calcium, and other trace elements. Secondary calcite formed through epigenetic alteration of the host rocks has a negative impact on the porosity and permeability of the reservoirs.

Background: The deep processing of hydrocarbon raw materials represents the most significant challenge in the oil refining. Nowadays, there are various technologies available worldwide to process heavy oil residues, which enhance the yield of light petroleum products. Among these, delayed coking is regarded as one of the most promising approaches.

Aim: To investigate how the properties of processed raw materials affect the quantitative and qualitative indicators of coking products, we conducted tests using fuel oil samples from the Atyrau Oil Refinery, as well as flux and tar obtained through vacuum distillation followed by subsequent coking at the pilot unit.

Materials and methods: A pilot delayed coking unit was employed for the systematic processing of heavy oil residues. Additionally, mathematical modelling and analysis of the experimental results have been performed to predict the behaviour and outcomes of the coking process under investigation.

Results: The article presents the findings from studies conducted on the coking processes of fuel oil, flux and tar sourced from the Atyrau Oil Refinery. The volatile matter yield index for “crude” coke derived from tar decreases is observed to decrease to 7.1%, while for “crude” coke from fuel oil and flux are 7.8% and 7.4%, respectively. The ash content of coke obtained from tar is measured at 0.29%, whereas samples from fuel oil and flux yield ash contents of 0.23% and 0.26%. These measured values of ash content, volatile matter yield, and the mass fraction of silicon, iron, and vanadium for coke obtained from tar, meet the technical requirements for coke. Additionally, a mathematical prediction of the process was conducted, employing express determination to assess both qualitative and quantitative indicators of the resulting products.

Conclusion: Based on experimental data of the delayed coking unit of Atyrau oil refinery, better quality coke was obtained at the processing of tar compared to the processing of fuel oil and flux. The proposed model can be used to predict the coking process by express-determination of qualitative and quantitative indicators of the obtained products. The developed model can be used for personnel training in the field of modelling technological processes, since it does not require in-depth knowledge of programming, which makes it suitable for the initial training of specialists.

Natural hydrogen represents a sustainable and promising energy source that holds the potential to significantly contribute to a low-carbon economy. This article discusses origins, geological distribution, and methods used for detection of natural hydrogen. Through a review of existing literature, the primary sources of natural hydrogen formation have been identified. These include serpentinization, water radiolysis, disaggregation of rock, magma degassing, and weathering of the Earth’s crust. Among these processes, serpentinization is particularly significant as a key phenomenon occurring in mid-ocean ridges and subduction zones. This process involves the interaction of water with divalent iron resulting in the formation of hydrogen. The geographical distribution of natural hydrogen includes oceanic spreading centers, passive margins, subduction zones, faults, and intraplate regions. High concentrations of H₂ are frequently found in tectonically active areas, such as the San Andreas Fault and the Taoudeni Basin. Natural hydrogen can be detected using isotopic analysis and H₂/CH₄ ratios, which help to differentiate between mantle-derived and crustal origins. Despite current limitations in the research and exploration of natural hydrogen deposits, its production could significantly reduce the cost of hydrogen energy and accelerate the transition to sustainable energy. The study emphasizes the necessity for further investigation into the mechanisms of hydrogen generation, accumulation, and migration, as well as the development of extraction technologies. This overview organizes the current understanding of natural hydrogen and serves as a foundation for future scientific and practical advancements in this field.