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03. Bachelor's Thesis

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Open Access
IMPACT OF COVID-19 ON THE MINING SECTOR IN KAZAKHSTAN
(Nazarbayev University School of Mining and Geosciences, 2022-03-25) Kabdygaliyeva, Zere
The COVID-19 pandemic significantly affected various industrial fields worldwide. This thesis review report will discuss the impact of the outbreak on the mining industry. Despite the cautionary and restrictive measures undertaken immediately by the mining corporations to take the situation under their control, the industry experienced losses and difficulties. The major ones concerned the well-being of employees, their employment status, maintenance of supply chains and rates of export, issues with logistics, funding and unplanned expenses. The local economies of the countries that heavily depend on mining suffered extensively due to their Gross Domestic Product values dropping significantly. The aim of this review report is to provide a thorough analysis of the impact of the COVID-19 outbreak on the above-mentioned realms of the mining industry based on the examination of the cases of Kazakhstan, India, Brazil, South America, the USA, Mongolia, African and European countries. The thesis will provide the analysis of the local Kazakhstani mining companies’ strategies to overcome COVID-19 crisis and difficulties they faced. The thorough examination of the dominant six minerals on Kazakhstan's mining market, namely aluminum, chromium, lead, coal, iron and copper, that were affected by the pandemic will be based on the analysis of the data from the official sources. The pie charts, tables, and graphs are created based on the data taken from the Bureau of national statistics of the Agency for strategic planning and reforms of the Republic of Kazakhstan. The analysis is done by evaluating the causes of deviation of prices on the ores and minerals, delays in production, exploration, transportation, and fieldworks accompanied with the strategies to resolve the occurring issues. The situation in the global mining market at the beginning of the pandemic, including the specific situation within Kazakhstan's market, is provided in detail and compared to the current one. The correlations between the flow of the COVID-19 and the drop in mining production rates are included. Based on the analysis, the forecasts about the future of the mining industry and the speed of the recovery process are covered as well.
Open Access
BLOCK SEQUENCING ANALYSIS AND IMPORTANCE OF MINING RECOVERY AND DILUTION IN MINE PLANNING
(Nazarbayev University School of Mining and Geosciences, 2022-03-25) Alimzhanov, Akseleu
A critical step in open pit mining is determining the appropriate sequence of block extraction, which has a significant impact on mining profitability. The open-pit mining block sequencing issue, which emerges at this stage, is described to find the optimal sequence in which blocks should be extracted following numerous physical and technological restrictions. Moreover, mine planning should take mining recovery and dilution into account and engage fully in planning and optimization processes. The optimal mining block sequencing provides the highest net present value (NPV) of the project. This paper proposes a mathematical model and software computation for the open-pit mine block sequencing in open pit mining operations. The primary goal was to analyze sequencing, the ultimate pit limit, pushbacks, and scheduling simulation findings, which correspond to real-world mining projects in Datamine Studio NPVS, and compare with optimistic and pessimistic scenarios. The results showed the highest Net present value is observed in Pit no. 88 in the optimistic scenario (+20% in price) – 914,612,423 $, while the lowest NPV results were in the pessimistic scenario (-20% in price) - 356,593,171 $ in Pit no. 82 Moreover, possible optimization improvements of block sequencing, ore recovery and dilution will be addressed. To demonstrate the superior attributes of the enhanced model, an open-pit gold mine case study was presented. The combination of direct block sequencing and the traditional method allows for improving NPV results by 0.43% which is regarded as an achievable outcome. Mine planning software must develop and adapt to meet current requirements and improve innovative solutions to existing block sequencing problems.
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MINERAL RESOURCE ESTIMATION AND MINE PLANNING IN A GOLD-COPPER DEPOSIT: A MULTIVARIATE GEOSTATISTICAL PRACTICE
(Nazarbayev University School of Mining and Geosciences, 2022-03-31) Kuanyshev, Shingiskhan
In mining practices, the life of every mine begins with resource estimation and predicting the possible income from operations. Thus, the first step identifies the potential implementation of mine into actual operation. Due to these reasons, geostatistics and resource estimation are crucial part in mining engineering. Moreover, geostatistics offers an appropriate method for accurately determining several properties of a deposit that are critical for mine design. However, because of the complexity and high cost of sampling variables in mines, some challenges could be faced in determining the grades of present minerals. For instance, the estimation of a variable in a univariate deposit is much simpler than in the case of a multivariate deposit. In this regard, geostatistics has been evolving throughout the years to propose some solutions to this issue. For instance, the computation of cokriging instead of kriging is a good tool in determining the grades with lower error as it takes into consideration the correlation between two or several variables. In this study, the case of a real-life Australian multivariate deposit of gold and copper was taken into discussion. After computing ordinary kriging and receiving a block model, it was found out that there is a presence of a high correlation between Cu and Au. Thus, after realization of an idea of ordinary cokriging with keeping all the steps and details, the mine planning of both methods was done and compared. Therefore, it was concluded that in resource estimation, ordinary cokriging provided us with much better results with lower variance, leading to the superior outcomes in mine planning part including economic aspects. The results of this study showed that by using cokriging instead of kriging, it is possible to increase the NVP (net present value) of a mine project by approximately $120.000.000. However, after proceeding the modelling, some drawbacks of deterministic methods were established. For instance, smoothing effect and negative values in kriging and cokriging, as well as not taking into consideration the time value in mine planning step. Thus, the future research should be focused on the side of stochastic methods.
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APPLICATION OF THE POLYMER FLOODING TO ENHANCE OIL RECOVERY IN A SPECIFIC KAZAKHSTAN’S OIL FIELD
(Nazarbayev University School of Mining and Geosciences, 2022-04) Yerniyazov, Daniyar; Yesmukhambet, Madi
Oil and gas reservoirs at their initial state possess high energy that can be used for the extraction of natural resources for a long time. This period is called the primary production period. Primary recovery methods depend on the natural energy stored in the reservoir and nearby aquifer to produce oil. To generate oil (or gas), primary recovery relies on in situ fluids or rock expansion; particular techniques involve solution gas drive, gas cap drive, natural water drive, and rock compaction. In many reservoirs, a mixture of such recovery mechanisms exists, but one of them is usually dominant. Depending on the fluids and reservoir geometry, gravity can also help with recovery. However, primary recovery methods lose energy and oil production decreases with time. It is important to cover world energy demands, thus to keep oil production above economic limits secondary and tertiary recovery methods are applied. The specific Kazakhstan oilfield was produced by water flooding which is a secondary recovery method, which led to a high water cut. Additionally, the formation has high heterogeneity. Relying on previously mentioned factors, it was decided by the operating company to evaluate the applicability of polymer flooding through several laboratory tests. In this capstone project, rheology and thermal stability tests were performed for 4 different polymers. The purpose of this study is to find out the optimum polymer type with the most suitable concentration. Screening criteria are mainly according to the target viscosity of the polymer, which is 5 cp at reservoir conditions. The conducted experiments provided qualitative as well as quantitative results. All 4 polymers have demonstrated a proposed shear-thinning behavior. However, Polymer 1 showed abnormally high viscosity and that is why it was excluded. At the initial stage of thermal stability tests, roughly 10 days, viscosity degradation for all polymers was sharp. At the end of all evaluations polymers, 2 and 3 achieved a target viscosity of 5cp at concentrations of 1500ppm and 2100ppm respectively. Further experiments such as static and dynamic adsorption tests, core flooding, compatibility, and mechanical degradation experiments are suggested to fully examine the polymer behavior under reservoir conditions.
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EVALUATION OF GEOMECHANICAL RISKS ASSOCIATED WITH THE CUT & FILL MINING METHOD FOR NARROW VEIN MINING CONDITIONS
(Nazarbayev University School of Mining and Geosciences, 2022-04) Kamilya Omirzhankyzy
The main objective of this research project is to delve into geomechanical risks associated with the cut & fill mining method for narrow vein mining conditions. The cut-and-fill method is a highly selective underground mining method based on removing horizontal slices and filling the mined stopes with backfill. Controlling geotechnical design parameters and operational factors, affecting the method for a given underground mining condition, will be considered from a risk assessment point of view. Given the complicated nature of the rock mass in-situ, and complicated boundary conditions and operational complexities associated with cut and fill mining at depth, the selection of a safe and economic mining operation is of paramount significance. Rock failure at varying scales within the underground mining openings is always a threat to mining operations and causes human and capital losses worldwide. Geomechanical design is a major design component of all underground mines and dominates the safety of an underground mine. With regard to the uncertainties exist in rock characterization prior to mine development, there are always risks associated with inappropriate design as a function of mining condition and the selected mining method. Uncertainty often results from the inherent variability of rock mass, which in turn is a function of both geological materials and rock mass in-situ conditions. In this study a typical cut and fill mining condition at high depth will be simulated numerically. For this research, the 2D numerical modelling using the finite element method is implemented to assess the effect of the parameters on the stability of the mine. The focus of this research is to conduct a comprehensive analysis looking into key design parameters associated with the method and assess risks associated with geomechanical design parameters. The obtained results will be verified against field data and risk proneness of key geomechanical design parameters will be discussed. As a result, the developed evaluation of geomechanical risks will offer a more complete way of assessing the stability of the underground working environment in terms of industry knowledge of ground behavior and stress distributions.
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DEVELOPMENT OF A DAMAGE/FAILURE MECHANISMS DATABASE FOR KAZAKHSTAN UNDERGROUND MINING INDUSTRY
(Nazarbayev University School of Mining and Geosciences, 2022-04) Akhmedya, Madyar
Mining is recognized for being one of the most dangerous industries in the world due to the difficult working conditions. Working in such hazardous circumstances in an underground mine often results in a variety of accidents. The working conditions at Kazakhstan’s underground mines have deteriorated owing to a lack of a risk-reduction plan and methodology. This paper evaluates different underground mines in Kazakhstan, demonstrates the employed mining method and observed failure modes. Risk assessment has long been recognized as a valuable technique for preventing accidents. In the underground mining sector, risk assessment tools play an important role in avoiding work-related accidents. However, geotechnical uncertainty is a significant source of severe incidents like stress-induced roof collapse, wedge failure, seismicity, etc., which result in human and financial losses. A geotechnical risk assessment performed early in the mine design process might assist justify a different mine design component, such as different support systems for a dangerous location within the mine openings during mining. As a result, the goal of this research is to create a damage/failure database aiming at the development of a geomechanical risk assessment methodology. This work identifies a thematic structure linked to risk assessment and management for the examined Kazakhstan mining sector. The developed database illustrates the dominant modes of failure within the Kazakhstan underground mining conditions. The second goal of this research is to determine practical design guidelines and charts between key and governing geomechanical design parameters. The study will provide opportunities to establish future research objectives for Kazakhstan mining industry where there are significant gaps between state-of-the-art research and mining operation in practice.
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EFFECTS OF VOIDS AND FRACTURES ON SEISMIC WAVE VELOCITIES USING PHYSICAL LABORATORY MODELS
(Nazarbayev University School of Mining and Geosciences, 2022-04-01) Yessengossov, Zhangir
Seismicity is a crucial factor that should be considered in underground mines, it occurs due to natural earthquakes or due to human induced activity, primary reasons might be excavation of an orebody, construction of haulage roads and tunnels, and mined out zones. From seismicity phenomena our focus will be on voids and fractures that occur because of a mining activity. Mining activity leads to the occurrence of rockbursts, which is a sudden release of energy in the rock mass. Even though this research area was studied for decades, there is no reasonable solution on these issues, since rockbursts defy conventional explanation. One of the proposed solutions is a use of microseismic monitoring systems that helps to forecast rockbursts and mitigate their negative impact on mining activity. Because underground mining environment with voids and fractures constantly changes makes this issue more complex. Moreover, there are some examples of successful implementation of seismic monitoring systems and 3D velocity models. Also, voids occur due to backfilling of mined out zones, where strength and composition of a backfill may degrade with time. So, considering those facts, the research includes laboratory models in form of synthetic sample cubes made up of concrete with different curing times and different cement concentrations, allowing to capture data from different samples. The main idea behind this study is to measure seismic wave velocities by using acoustic emission systems (AE). This system allows us to record seismic wave velocities passing through voids, to know wave propagation patterns inside sample cubes. The result of this research compares seismic wave velocity against sample cube dimensions, presence of holes, and concentration of a backfill. Furthermore, this research proposes utilization of artificial neural networks (ANN) as tool that may enhance rockburst mitigation in the future.
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CHARACTERIZING THE SHAFT DEFORMATION IN THE TISHINSKY MINE SUBJECTED TO SURFACE SUBSIDENCE
(Nazarbayev University School of Mining and Geosciences, 2022-04-04) Smagambetov, Bekzhan
Shafts play an important function in terms of safety and profitability throughout the life of a mining operation. The access shaft stability has always been a significant challenge in mining engineering, especially as mining depths have increased. Therefore, it is vital to determine the deformation and failure mechanisms of the about 970 m shaft in the Tishinsky mine where the main shaft has experienced major deformation together with surface subsidence. Driven by these reasons, the aim of this study is to characterize the ground deformations and movements in order to establish any relationship between the surface deformation and the shaft deformation. To this end, ground monitoring data were collected and analyzed. It was found that the shaft deformation was highly correlated with both horizontal and vertical surface displacement, especially for 2018-2019. The maximum deformation reached 0.07 m at the level about 600 m. However, the deformation decreased in 2020 after ground control measures were taken.
Open Access
INVESTIGATION OF UNPLANNED DILUTION IN OPEN STOPING MINING METHOD: A CASE STUDY OF THE RIDDER-SOKOLNY MINE
(Nazarbayev University School of Mining and Geosciences, 2022-04-10) Bolegenov, Adil
The open stoping mining method is considered as one of the most common mining methods for steep orebodies due to its several advantages. However, open stopes are susceptible to unplanned dilution. Dilution can jeopardize the profitability of the mining operations because it increases the production cost. This has been the case in the Ridder-Sokolny mine, where large amount of unplanned dilution was observed. The thesis is aimed to characterize the unplanned dilution experienced in the Ridder-Sokolniy mine and to develop an alternative open stope design tool to the conventional ELOS graphs used in that mine. Unplanned dilution data and design parameters of 107 stopes were collected. Firstly, the performance of the ELOS method was evaluated. Next, the multinomial logistic regression model was implemented to derive probabilistic charts relating the unplanned dilution and its two key influencing factors. The results showed poor to fair agreement with the actual unplanned dilution with the ELOS method. Therefore, this design method is not reliable for unplanned dilution in Ridder-Sokolny mine. On the other hand, the proposed charts indicated that the generated probabilistic map provide desirable accuracy of 63% for estimation of unplanned dilution in stopes. It was concluded that the multinomial logistic regression charts could be used to design open stopes as they can assist in selecting the stope dimensions that would minimize unplanned dilution.
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PRELIMINARY ASSESSMENT OF TIO2@PVP (POLYVINYLPYRROLIDONE) NANOCOMPOSITE FOR IFT REDUCTION AND WETTABILITY ALTERATION IN INDIANA LIMESTONE – EOR IMPLICATIONS
(Nazarbayev University School of Mining and Geosciences, 2022-04-15) Yessengali, Dariya; Khashiyev, Sultan
The application of enhanced oil recovery (EOR) methods is inevitable to address the global demand for fossil fuels in the foreseeable future when oil and gas are a notable portion of the world energy basket. Over half of the global oil reserves occur in carbonate reservoirs, which make them a primary EOR target. Recently, the application of nanotechnology in the petroleum industry and particularly using nanoparticles (NP) as chemical EOR agnates has become one of the hot research topics. However, nano-EOR is still in its early stage of development and further research is required on different aspects of this subject. The main objective of this capstone project was to conduct a preliminary assessment of the effect of TiO2-coated polyvinylpyrrolidone (TiO2@PVP) on IFT reduction and wettability alteration in Indiana limestone. TiO2@PVP nanocomposite was used to prepare nanofluids (100, 250, 500, and 1000 ppm). The tested TiO2@PVP nanocomposite was characterized using Fourier-transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). The FTIR revealed the presence of C–O–C, C–C, Ti–O–C, and Ti–O groups in the nanocomposite. The TEM results also showed that the average size of nanocomposite is 77.4 nm ranging from 66.4 nm to 91.2 nm. The IFT and contact angle measurements were also conducted. Based on the experimental results, the minimum IFT was seen at 250 ppm (18.23 mN/m) compared to IFT in the absence of nanocomposite (91 mN/m). 250 ppm is considered the optimum concentration for the use of TiO2@PVP nanocomposite. The contact angle measurements revealed that the TiO2@PVP nanofluid can alter the wettability from oil-wet to water-wet state. Treatment of rock samples with 250 ppm nanofluid resulted in the highest contact angle reduction by 43.4%, reducing it from 107.8° to 61.0°. The contact angle results agreed with IFT results and confirmed that TiO2@PVP nanocomposite is a potentially proper EOR agent in carbonate reservoirs.
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GEOTHERMAL ASSESSMENT OF A DEPLETED NATURALLY FRACTURED RESERVOIR IN ZHARKENT BASIN: A REVIEW
(Nazarbayev University School of Mining and Geosciences, 2022-04-27) Kutzhanov, Rysbek
Although contemporary study is sparse, several researches have been undertaken to analyze the expected energy production potential of Kazakhstan's sedimentary geothermal resources. The available evidence demonstrates the potential is scattered, fragmentary, and not always consistent. However, detailed data on geothermal resources exist in Kazakhstan's national archives and should be gathered and evaluated. Kazakhstan is considered to possess significant low-temperature geothermal resources, mostly in sedimentary basins in nature. Kazakhstan's population has a substantial demand for acceptable heating services, and low-temperature geothermal resources are particularly well suited for district heating and other direct consumption applications. The basins of Ustyurt-Buzashin and Manguyshiak in SW Kazakhstan and the W-Ily (Almaty) and E-Ily (Zharkent) basins in SE Kazakhstan are thought to have the highest concentrated potential. Due to their relatively large surface area, the first two are also among the basins with the most extractable energy per basin. Basins having a high extractable energy density (per km2) are considered the most promising for geothermal potential, since they should need less widespread drilling of production wells. The geothermal resources in the Zharkent sub-basin in southern and southern-eastern Kazakhstan look to be the most promising, based on their high geothermal gradients, low concentration of dissolved solids, and significant natural recharge via precipitation. Other research in the South and South-East area may uncover additional viable geothermal resources. Due to the closed nature of the majority of sedimentary geothermal reservoirs, reinjection can be applied. After energy has been recovered from the water, geothermal reinjection involves returning part, or possibly all water produced from a geothermal reservoir back into the geothermal system. Water from a different source is sometimes injected into geothermal reservoirs. This will not be essential immediately in all sites inside the Zharkent sub-basin due to natural recharge, but will become necessary over time as geothermal development increases. Most other sedimentary geothermal resources in Kazakhstan will undoubtedly require the reinfection process from the start of large-scale usage.
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ENVIRONMENTAL GEOCHEMISTRY AND MINERALOGY OF TANTALUM AND NIOBIUM AROUND A LCT PEGMATITE DEPOSIT OF THE RUDNY ALTAI, EAST KAZAKHSTAN
(Nazarbayev University School of Mining and Geosciences, 2022-04-30) Zhalgasbayeva, Assel
Tantalum (Ta) and Niobium (Nb) are critical metals required in many applications related to the energy transition. They are typically found in rare-metal pegmatites, where they occur in minerals of the tantalite – columbite series (Fe,Mn)(Ta,Nb)2O6. The geochemistry of Ta and Nb in high-temperature magmatic systems is well understood by igneous petrologists. In contrast, although they are not considered particularly toxic, very little is known about their behavior in low-temperature environments. During a visit to a LCT (lithium-cesium-tantalum) pegmatite in the Altai, a number of Li-, Cs-, and Ta, Nb-bearing minerals were sampled. The locality also offers the possibility to sample soils and stream sediments. A preliminary review of the bibliography of Ta and Nb is first presented. Then the diversity of Ta and Nb minerals found in the last International Mineralogical Association (IMA) list of accepted minerals discussed and some conclusions regarding the possibility of identifying new minerals that have not been described previously. The main objective of this research is to extend the knowledge on the low-temperature aqueous geochemistry of tantalum and niobium minerals. The objective can be broken down into several smaller objectives, which are classification of all the approved Ta- and Nb-bearing minerals, sample the sediments in Asubulak and make an XRF elemental analysis, and derive the thermodynamic properties of the tantalite-columbite minerals at low-temperature and pressure via polyhedral regression analysis method. The results of the XRF analysis and the thermodynamic calculations showed the tantalite-columbite minerals are hardly soluble, and the source of tantalum and niobium in the weathered and aqueous environment must from less stable lepidolite mineral candidate and the phase is ‘aged’ Ta2O5.
Open Access
GEOCHEMICAL STUDY OF CHROMIUM IN THE AKTOBE REGION OF KAZAKHSTAN
(Nazarbayev University School of Mining and Geosciences, 2022-05) Serikova, Alin
Chromium and its derivatives are extensively used worldwide in various industries, resulting in vast amounts of this metal being released into the environment. Chromium-VI is a well-known toxin and carcinogen generated by anthropogenic activities. Pollution with hexavalent chromium is a severe environmental concern in many countries, including Kazakhstan, since it is the first largest chromium manufacturer globally. In order to discharge the water bodies and soils contaminated with hexavalent chromium, it is essential to predict the physicochemical conditions prevalent in the aqueous environment and soil. If there is a prevalence of any waste and heavy metals, it is vital to treat the water prior to discharge. Several toxic chromium remediation strategies are being used worldwide; however, they have not been implemented in Kazakhstan yet. In this research, three methods of chromium reduction are proposed: chemical reduction, bacterial reduction, and ion exchange. A geochemical modeling study should make it possible to choose the accurate method for hexavalent chromium reduction. 1
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GEOTHERMAL ENERGY POTENTIAL IN THE EASTERN SYR DARYA SEDIMENTARY BASIN, SOUTH KAZAKHSTAN
(School of Mining and Geosciences, 2023) Karakozhayeva, Ayana
Since Kazakhstan is one of the world’s top polluters in terms of CO2 per capita emissions, the Strategy of Sustainable Energy of Future Kazakhstan until 2050 recommends a substantial reliance on renewable energy sources. Geothermal energy can be used in Kazakhstan's decarbonization agenda in addition to solar and wind energies. This research provides an initial evaluation of the geothermal energy potential in the Eastern Syr Darya sedimentary basin. The regional temperature distribution maps were produced with the input of depth-temperature profiles that represent the geothermal gradients of each observed area. Integration of temperature distribution maps with heat content and available water salinity indicated that the Arys and Shaulder areas, where salt layers are absent, are promising regions for geothermal energy extraction. Elevated geothermal gradients are potentially explained by the recent tectonic activities, particularly, strike-slip faulting and compressional tectonic regimes. An examination of the water chemistry determined the surface water and lateral groundwater flow recharge zones of the Eastern Syr Darya aquifers. Implementing experience in other countries, geothermal energy in the Eastern Syr Darya can be successfully extracted for electricity generation and heat supply.
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DISAPPEARING WETLANDS IN NORTHERN KAZAKHSTAN. THE CASE OF THE TALDYKOL LAKE.
(School of Mining and Geosciences, 2023) Kairat, Akbota
Wetlands play a crucial role in the ecosystem by providing shelter and food for various species and contributing to groundwater replenishment, water retention, and detention. They also prevent flooding in nearby ecosystems and maintain high water tables. However, wetlands have been significantly reduced, with an approximately 70% decrease from the previous century, particularly for inland natural wetlands. Anthropogenic activity and climate change have caused the Central Asian wetlands to be severely impacted globally. However, there is still a lack of precise data on the amount, area, and coverage of wetlands in Kazakhstan. Therefore, this research project focuses on assessing the impact of climate change and human activity on wetlands in Kazakhstan, with Taldykol Lake in Astana as a case study. The study will investigate Taldykol Lake’s changes over the last three decades, from 1992 to 2022. 3
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RESERVOIR ARCHITECTURE OF THE SOUTH TORTKUDUK URANIUM FIELD
(School of Mining and Geosciences, 2023) Gabdullina, Saltanat
The uranium deposits hosted by Uyuk and Ikansk formations in the South Tortkuduk field (Chu Sarysu basin, Southern Kazakhstan) over the next two decades will be exploited by in-situ leaching/ in-situ recovery technology. Traditional reservoir and ore body mapping is based on lithological and/or more often empirically derived criteria such as expected thicknesses from reliable geological markers. Observations from Tortkuduk 18Y uranium deposits allowed proper visualization of sedimentary logs, which in turn was helpful in the determination of the depositional environment. Well-log correlations according to the depths and lithology allowed a better visual understanding of the local depositional systems. Comparison of interpreted fining-upward and coarsening-upward trends from the cross-sections suggest point-bar and tidal-dominated delta, respectively
Open Access
PHYSICO-CHEMICAL OF POLYANIONIC CELLULOSE (PAC-R) POLYMER ON BONDING ABILITY IN THE CEMENTING MATERIAL USED FOR OIL AND GAS WELL
(School of Mining and Geosciences, 2023) Kuvanchbay, Bekzat; Tolegen, Bektas
The ability of the cement sheath to bond effectively with the casing or formation depends on its tensile strength and Young's modulus, which determine its ability to withstand deformation under load without separating. The aim of this research was to explore the impact of the concentration of PAC-R copolymer and the duration of curing on the bonding capacity of the cementing substance utilized in oil and gas wells. The study carried out two sets of experiments to assess the chemical and mechanical features of the cement specimens. The compressive strength of the samples was measured after curing for 1 day and 3 days at 80 ℃ in an OFITE curing chamber. The uniaxial test results showed that samples with 10% and 20% PAC-R copolymer concentrations had significantly lower axial loads and axial stresses compared to control samples. As the amount of polymer was raised from 10% to 20%, the compressive strength also went up. This happened because the polymer was able to fill in tiny cracks and gaps in the cement, making the matrix more uniform and compact. As a result, it became more resistant to being compressed. The reduction in the Young modulus was particularly noticeable when using a 10% PAC-R copolymer concentration. As the polymer concentration increased from 10% to 20%, the Young modulus values displayed an inclination to rise.
Open Access
ASSESSMENT OF THE POTENTIAL OF NATURAL SURFACTANT IN CARBONATE RESERVOIR
(School of Mining and Geosciences, 2023) Sabirova, Aruzhan; Zhuniskenov, Yermukhan
One of the main drawbacks of chemical enhanced oil recovery (CEOR) is to reduce the excessive use of chemicals. Recently, natural surfactants got recognition in CEOR since they are environmentally friendly, less toxic, and cheaper than traditional synthetic surfactants. However, the applicability of natural surfactants has yet to be tested under different conditions; thus, the research focuses on the natural saponin synthesized from the flaxseed oil available in Kazakhstan and its effect on efficiency of the available synthetic oil, octane. The primary extraction method was conducted by the saponification of the flaxseed oil. The study used the IFT-700 apparatus, which uses the pendant drop method to determine the interfacial tension (IFT) between surfactant and oil. The salinity variation between 0 and 35,000 ppm of NaCl resulted in critical micelle concentration (CMC) values of about 6 wt% for the solution with distilled water (DIW) and 2.5 wt% for the brine surfactant solution. The effect of temperature on the rheological properties of the natural surfactant solution was measured in the range of 25–55 °C. Interfacial tension alteration with oil at the CMC values for DIW and brine surfactant solutions was observed, with 76.36 and 48.54% IFT alteration, respectively. The core flooding with surfactant solutions resulted in an oil recovery of 72% for DIW and 74.6% for the brine solution. This study presented the potential of the extracted natural surfactant for the CEOR application as a low-cost and more accessible alternative to the traditionally used surfactants. Technically, the natural surfactants need more studies for their performance under salinity and temperature. However, the study is a direction to unmask the potential of Kazakhstan natural resources to fulfil its oil industry chemical needs.
Open Access
OIL DISPLACEMENT BY POLYMER FLOODING IN THE UZEN FIELD
(School of Mining and Geosciences, 2023) Bukayev, Azamat; Kenes, Razida
Primary recovery is the production of the hydrocarbons under the natural energy of the reservoir. As the reservoir energy depletes and pressure reduces, production also declines. Secondary recovery methods such as water and gas injection are typically applied after the decline in production has been noticed. When the production of hydrocarbons is not enough, tertiary recovery methods are applied. Chemical flooding is one of the most used techniques to maintain oil production, especially polymer flooding. Polymers are applied to the reservoirs with high water cut since polymers are effective in increasing the sweep efficiency and mobility control. By adding more viscous fluid such as polymer to the water, water becomes more viscous and is able to move more oil from the injection well towards the production one. One of the Kazakhstan fields, where the water cut is very high, is the Uzen field. That is why polymer flooding has been considered for this field. In previous studies, screening of four types of polymers has been completed, after which Polymer 3 solution with a concentration of 2500 ppm was established to be the most suitable for this field. In this paper, Polymer 3 then has been further tested with different kinds of water - Caspian seawater and Alb water (water from Albian age layer) - to study its behavior when injected into the Uzen core sample to displace oil. The results of the oil displacement tests conducted through the Core Flooding System (CFS-700) have shown that polymer prepared with Caspian seawater works better than polymer prepared with Alb water in terms of oil recovery, injectivity, and resistivity factors. The next step of the research is to conduct pilot tests in the field and monitor the polymer behavior in real conditions.
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APPLICATION OF GEOSTATISTICAL HIERARCHICAL CLUSTERING FOR GEOMETALLURGICAL DOMAINING
(School of Mining and Geosciences, 2023-03-17) Abil, Akmaral
Geometallurgical modeling is a pivotal component in the mining industry, serving to optimize ore processing and maximize profits. Machine learning techniques have gained immense popularity in this field due to their ability to group geological domains that possess similar mineralogical and metallurgical characteristics. The present research work delves into investigating the application of geostatistical hierarchical clustering (GHC) in geometallurgical modeling and the derivation of recovery functions. The research specifically targets a copper porphyry deposit situated in central Kazakhstan. Three clustering methods, namely, K-Means, K-Prototype, and GHC, were employed, with GHC proving to be the most effective. The other methods demonstrated satisfactory results applicable in simple cases requiring quick analysis. GHC affords flexibility in adjusting various factors, such as the coordinate and variables weights, takes into account spatial dependency, and allows for easy alteration of the minimum number of clusters. Post-clustering, multivariate regression analysis was performed in each domain, and both linear and nonlinear models were evaluated for their appropriateness. The nonlinear random forest model was deemed the most suitable, with an R2 index of 0.8746. Although the recovery equation could not be obtained in an algebraic form due to the complexity of the geological dataset, future recovery values can be predicted through machine learning by incorporating parameters into the model. The study found that the copper recovery function comprised independent variables such as throughput, P80, sulfur-to-copper ratio, aluminum oxide, and silver. The study recommends that this methodology be replicated on a larger dataset, as the provided one was restricted to a small portion of the entire block model. This research work contributes to the field of geometallurgical modeling by showcasing the potential of GHC for domaining and machine learning in enhancing the accuracy of recovery function derivation in the mining industry.