Kazakhstan journal for oil & gas industry

Background: Development of a geological framework to substantiate and quantitatively evaluate the hydrocarbon potential of the Balkhash sedimentary basin cover.

Aim: Identification of the key estimation parameters for potentially promising hydrocarbon plays (area, thickness, lithological composition) on a qualitatively new geological lithological and stratigraphic base for determining the hydrocarbon potential of the Balkhash sedimentary basin.

Materials and methods: Correlation of lithological and stratigraphic sequences of Mesozoic (Triassic-Cretaceous) and Cenozoic (Paleogene-Neogene) deposits in accordance with the stratigraphic charts of the Phanerozoic of Kazakhstan based on the International Chronostratigraphic Scale from 2016 to 2021.

Results: The paper investigates the geological structure, zoning, and platform cover of the Balkhash sedimentary basin (BB). During the study, two tectonic units were identified within the BB structure: the West Balkhash and East Balkhash (Lepsin) depressions. Lithological and stratigraphic charts of the Balkhash sedimentary basin have been created and refined to serve as a basis for appraising its hydrocarbon resources. Additionally, prospective hydrocarbon plays have been identified, and their thicknesses have been measured. Furthermore, the analysis of lithological and stratigraphic data has allowed for the determination of the thicknesses, distribution areas of these discoveries, and the organic carbon content within them. These parameters are critical for calculating predicted hydrocarbon resources. Data regarding the development areas of promising BB hydrocarbon plays were obtained from the results of constructing lithological and paleogeographic maps and sections.

Conclusion: Based on the developed lithological and stratigraphic model, charts of the Balkhash basin have been drawn up allowing for appraisal of the hydrocarbon potential. The oil and gas potential of the region is estimated to be very low due to the characteristics of the sedimentary cover structure, tectonic activity, and types of possible traps. However, we have identified prospective gas plays that exhibit certain capacities, areas, and organic matter content.

Background: In high-pressure carbonate reservoirs, miscible gas injection is a key method for enhancing oil recovery and maintaining reservoir pressure. The main challenge lies in controlling bottomhole pressure (BHP) and tubing head pressure (THP) while maximizing injection volumes and preventing formation fracturing. Current strategies typically rely on THP regulation and injection rates as the primary means of well control.

Aim: This study aims to analyze an optimized gas injection strategy based on precise well control to prevent formation fracturing and improve injection efficiency.

Materials and methods: The study uses production and geological data analysis, empirical forecasting models, and statistical techniques to enhance the accuracy and reliability of predictions. Modern algorithms and data-processing technologies are applied to handle large datasets, allowing for more accurate and consistent forecasts of key field development indicators.

Results: The results indicate that gas injection can be optimized by lowering reservoir pressure and increasing tubing head pressure (THP). This stabilizes bottomhole pressure (BHP) because of increased frictional losses in the tubing string. Controlling THP and gas rates allows stable BHP operation. Currently, maximum BHP limits have been established for the wells, while allowable THP is restricted but can be increased based on previous test results. An increase in THP would enable higher gas injection volumes, leading to improved oil recovery. BHP remained within safe limits and was monitored directly with downhole pressure gauges.

Conclusion: This study presents an optimized approach to gas injection management, based on real-time pressure monitoring, well–reservoir nodal analysis, dynamic control of tubing head pressure (THP), and regulation of gas flow rates. The results emphasize the need to consider nonlinear pressure losses when designing safe and efficient injection strategies. Considering these effects helps prevent formation fracturing and ensures long-term reservoir integrity.

The article explores the application of Artificial intelligence in the oil industry, focusing on the transformation of data into new energy sources. Artificial intelligence is used to optimize oil extraction and refining processes, contributing to increased productivity, reduced costs, and enhanced safety. The implementation of innovative algorithms, such as machine learning and the Internet of Things, significantly improves forecasting accuracy, the identification of hidden patterns, and process automation. These technologies help effectively manage risks, minimize costs, and accelerate operations, while also enhancing environmental sustainability. Artificial intelligence promotes the rational use of natural resources and reduces environmental impact, improving both economic and environmental performance of oil companies. Overall, the use of Artificial intelligence in the oil industry opens up new opportunities for more efficient and environmentally friendly production, making processes more sustainable in the long term. 

Background: The use of bitumen-polymer composites is a relevant and promising approach to improving the performance characteristics of bituminous materials in road construction. Studying the structure and interaction mechanisms of components in such composites enables the optimization of formulations and enhancement of the final product’s quality.

Aim: The aim of this research is to investigate the structure and the nature of interactions between the components of bitumen-polymer composites based on bitumen, polypropylene, and heavy petroleum residues using infrared (IR) spectroscopy.

Materials and methods: The IR spectroscopy method was used to analyze structural changes in the composites. The spectra of the initial components (bitumen, polypropylene, heavy petroleum residues) and the modified bitumen were studied. A comparative analysis of the position and intensity of characteristic absorption bands corresponding to the main functional groups was carried out.

Results: It was found that the introduction of polypropylene causes changes in the bitumen absorption spectra, particularly in the region of the stretching vibrations of carbon-hydrogen and carbon-oxygen bonds. This indicates structural transformations and redistribution of molecular interactions within the system. The additional incorporation of heavy petroleum residues amplifies these effects, resulting in changes in the physical properties of the composite, – notably, increasing the softening temperature and decreasing penetration. It was shown that the degree of interaction between components depends on polymer concentration and modification conditions.

Conclusion: The obtained results reveal the mechanisms of structure formation and component interaction in bitumen-polymer composites, providing a scientific foundation for optimizing modified bitumen formulations. The work contributes to the development of research methodologies and expands the application of bituminous materials in construction and road industries.

Background: Improving technologies for lost circulation control and water shutoff remains a key priority in drilling oil and gas wells. In West Kazakhstan, which holds significant hydrocarbon reserves, various methods are applied, including cement slurries, lost circulation materials (LCM) of different particle sizes, and high-viscosity or polymer systems. Despite notable progress in cementing technologies, universal solutions that combine lost circulation control with water shutoff are still scarce. Their effectiveness is highly dependent on the geological and technical conditions of each field. Current research focuses on selective materials that adapt to reservoir heterogeneity and deliver reliable sealing.

Aim: This study summarizes field experience with lost circulation and water shutoff technologies in wells drilled in West Kazakhstan. It also analyzes existing isolation materials and systems in terms of their effectiveness, limitations, and future potential.

Materials and methods: The study used data from wells drilled in West Kazakhstan, results of field tests, and patent and technical literature on modern cementing and isolation materials.

Results: This study reviews existing isolation systems, their mechanisms, and limitations, supported by field examples and patented technologies. A key focus is the concept of a universal sealing material able to address both lost circulation and water shutoff. This approach could enhance the efficiency of isolation treatments, lower operating costs, and reduce environmental risks.

Conclusion: The effectiveness of isolation treatments depends on both the proper selection of materials and the technology of their application. The analysis of existing solutions indicates that, despite a variety of options, consistent performance is not always achieved under complex geological conditions. Therefore, further research is required to optimize formulations and adapt technologies to the specific characteristics of regional fields.

Background: With light oil reserves depleting and the demand for lubricants steadily increasing, the development of alternative sources of hydrocarbon feedstock has become a pressing issue. Despite the technological complexity of processing, natural bitumens represent a promising raw material for the production of base oils, particularly in the Republic of Kazakhstan, where domestic industrial lubricant production is currently absent.

Aim: To assess the possibility of obtaining base industrial and motor oils from oil fractions derived from the fuel oil of natural bitumen at the Karasaz-Taspas deposit.

Materials and methods: on the study object was fuel oil obtained by atmospheric distillation of natural bitumen. Oil fractions with boiling temperature ranges of 350–400 °C and 400–460 °C were separated using vacuum distillation. Purification was carried out using bleaching clay. The physical and chemical characteristics of the fractions were determined before and after purification according to standard ASTM and GOST methods.

Results: The obtained oil fractions are characterized by a high kinematic viscosity, a viscosity index of up to 110.7, and low sulfur content (<0.45 wt.%). Their physical and chemical properties meet the requirements for base oils of groups I and II according to the American Petroleum Institute classification and are comparable to industrial oils of grades I-40A and I-50A. Dewaxing and the addition of additives are necessary to improve low-temperature performance.

Conclusion: Natural bitumen from the Karasyaz-Taspas deposit is a promising raw material for producing high-quality base oils. The study confirms the feasibility of comprehensive processing of natural bitumen fuel oil to produce industrial and motor oils, contributing to the replenishment of the raw material base, the sustainable development of the oil industry, and the enhancement of the country’s energy security.

Background: In the global transition to low-carbon energy, hydrogen is becoming an important energy carrier. Adapting existing pipelines for hydrogen transportation can reduce costs and accelerate the development of hydrogen infrastructure. However, the use of pipelines in a hydrogen environment is associated with risks such as hydrogen embrittlement and metal cracking. Kazakhstan still lacks practical experience in the operation of hydrogen pipelines, which makes the task of assessing the technical condition of existing pipelines and their adaptation for operation with hydrogen urgen.

Aim: To conduct a comprehensive analysis of the integrity of the pipeline operated in an aggressive hydrogen sulfide environment and to assess the possibility of its repurposing for hydrogen transportation taking into account international standards and methods of strength calculation.

Materials and methods: The data of in-line inspection (ILI) including ultrasonic testing of wall thickness were used in the work. API 579 standards were used for defects assessment. Calculations were performed using NIMA software, which allows analyzing data on laminations and cracks in metal.

Results: The analysis identified six sections with laminations, of which five were found to be acceptable for service at the current operating pressure of 75 bar. One defect (#6) was classified as unacceptable, requiring either immediate repair or a reduction in operating pressure to 52 bar.

Conclusion: The study confirmed that conversion of existing gas pipelines for hydrogen transportation is feasible provided thorough diagnostics and compliance with international standards for strength assessment. Implementation of regular pipeline condition monitoring and development of a phased repair strategy to improve infrastructure reliability in hydrogen environment is recommended.

Background: PVT modeling is a critical step in reserve estimation and reservoir simulation of oil and gas fields. Accurate reproduction of fluid properties under different pressure–temperature conditions increases confidence in calculations and improves production forecasts. The accuracy of a PVT model largely depends on the quality of laboratory fluid data, while inconsistencies or errors in experimental results can reduce the reliability of calculated parameters.

Aim: To evaluate the quality and reliability of laboratory data on reservoir fluids from the Cretaceous horizons and to validate consistent PVT regions for model development.

Materials and methods: The quality and reliability of laboratory studies were evaluated using PVTsim software and methodological guidelines for validating reservoir fluid properties, where fluid composition and properties were analyzed based on equations of state.

Results: Analysis of bottomhole and recombined samples showed clear relationships between reservoir fluid properties. Several PVT regions with distinct characteristics were identified. Comparison of simulation results with laboratory data revealed discrepancies, particularly in the measured density of Albian horizon oil. Reservoir oil parameters were adjusted using the PVT model.

Conclusion: This approach removed unreliable laboratory data, provided a more accurate description of reservoir fluid properties, and updated calculation parameters to refine resource estimates.

ABSTRACT

Background: Core analysis is a key method for directly evaluating the properties of promising or existing reservoirs. Core data can be used to determine the sedimentological and diagenetic characteristics of rocks, which are critical for assessing their filtration and storage properties. This article presents the findings of a core digitization project, including the application of advanced technologies for analysing high-resolution panoramic images of thin rock sections.

Aim: Development and implementation of digital technologies for automated core analysis, including determining porosity and grain size composition from panoramic images of thin rock sections, aim to enhance research accuracy and efficiency over traditional methods, aligning with academic standards.

Materials and methods: The study describes methods for automated determination of porosity and grain size distribution, as well as their integration with conventional research techniques.

Results: The results demonstrate a significant improvement in analysis accuracy and efficiency compared to manual methods, as supported by statistical data from 147 thin rock sections.

Conclusion: The analysis of 147 thin rock sections from eight wells confirmed the effectiveness of digital analysis techniques, which significantly enhanced the accuracy of determining porosity and grain size composition of rocks. The data obtained served as the basis for developing detailed petrophysical models. This is critical for geological and hydrodynamic modelling. Future work includes the further expansion of digital core databases and the implementation of machine learning algorithms to predict reservoir properties.

This paper reviews current technologies for oil waste treatment and the remediation of oil-contaminated sites. Case studies include the cleanup of historically polluted soils at petroleum companies using EGX cavitation soil washing, BioBox bioremediation, conventional bioremediation, and humate-based composite additives with energy-accumulating properties. Results cover oil content in contaminated soils, residual hydrocarbons in remediated soils, and the volumes of restored soils, reclaimed areas, and decommissioned sludge pits.