02. Master's Thesis
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Item Embargo EXTENSION OF THE FAULT FACTOR TO ACCOUNT FOR STOPE BACKS IN OPEN STOPE DESIGN(Nazarbayev University School of Mining and Geosciences, 2024-04) Tokenova, KamilyaThis research addresses a critical gap in the existing methodology for open stope design by extending the application of the fault factor to account for faults in stope backs. The established fault factor, as introduced by Suorineni in 1999, currently focuses solely on faults near stope surfaces, neglecting their potential impact on stope backs. The aim is to improve the stability graph method for the open stope design by presenting a more comprehensive assessment that incorporates the impact of faults in stope backs. The research employs RS2 Rocscience Software, following the procedures outlined in Suorineni et al. (1999), and incorporates the brittle Hoek-Brown failure criterion. Failure in a rock mass is assumed to extend throughout the whole span of the excavation when the deviatoric stresses exceed one-third of the uniaxial compressive strength, in accordance with the extended Hoek-Brown failure criterion. This methodology enables a detailed analysis of fault-related damage in stope backs, contributing to a refined understanding of stope stability within the stability graph framework. The position, angle, and distance of the faults from the stope surface, k-ratio determine the extent of the increased compression zone surrounding the excavation in a two-dimensional model. These parameters' impacts on the compression zone size have been evaluated. The significance of this research lies in its potential to improve the overall stability assessment of stope backs, enhancing safety and economic feasibility in mining operations. Given the common occurrence of faults in orebodies, particularly those found in stope backs, the extended fault factor will provide valuable insights for mines applying the stability graph method.Item Embargo DEVELOPMENT OF AN UNPLANNED OVERBREAK INDEX FOR OPEN STOPE MINING: ACCOUNTING FOR DESIGN UNCERTAINTY(Nazarbayev University School of Mining and Geosciences, 2024-04-18) Bolegenov, AdilUnplanned dilution can pose a huge burden on the profitability of operations in mines exploiting open stoping mining methods if these are not adequately designed. The empirical stability graph methods are commonly used for these purposes due to their practicability. Despite their merits, experience shows that these graphical design methods can also lead to excessive unplanned dilution which is not surprising since the stability graph method is an approximate design method by nature. This is due to many reasons, for example the unavoidable uncertainties (both epistemic and aleatory) that come with design parameters. Therefore, there is an increasing need for more accurate design tools in the mining industry. Motivated by these aspects, the purpose of this research is to revisit the conventional stability graphs method for open stope design and to propose alternative design tools that could address some of the limitations of the conventional methods. To this end, firstly, a database of unplanned dilution cases collected from sublevel open stoping operations was compiled and the performance of the conventional stability graph method was examined. Next, based on the compiled data, a new overbreak index (DI) was proposed using the Rock Engineering Systems methodological framework. In addition, the effect of aleatory uncertainties on the stability graph method was explored through a reliability analysis. This was accomplished by using the First Order Reliability Method (FORM) to determine the probability of occurrence of unplanned overbreak. The overall results indicated that: the stability graph method yielded accuracies ranging from 9-78%, depending on the ELOS levels; the proposed Overbreak Index highly correlated with the actual ELOS values. In addition, the reliability analysis revealed that the probability associated with the unplanned ELOS varied between 15-100% depending on the rock domains and the wall types. It was concluded that the Overbreak Index and the reliability analysis results could be considered additional tools useful for a more reliable open stope design if uncertainties associated with input parameters of the design must be considered.Item Restricted WATER ACCOUNTING IN KAZAKHSTAN'S MINING(Nazarbayev University School of Mining and Geosciences, 2024-04-15) Meirambayeva, MiraMining activities can substantially influence water resources, and water availability is critically important, especially in regions subject to water scarcity. Therefore, gaining publicly available data on water usage within Kazakhstan’s mining sector and understanding its water use can provide valuable insights into broader industry practices. The objective of this study is to utilize the International Council on Mining and Metals (ICMM) water accounting framework to evaluate water use in a mining company in Kazakhstan. Particularly, this research aims to shed light on practices in water management at Kazakhstan’s mines and identify water-related risks. It was found that the Exploration Point mine site has successfully achieved a considerable level of water reuse during its operations, where water reuse grew by 8.74% annually, with an average reuse rate of 82% of the water used for operations. However, a substantial proportion of water is still entrained in waste, along with an excessive reliance on freshwater intake. According to these results, various barriers to water management were identified, and suggestions for improvement were proposed. Our research demonstrates presence of opportunities to optimize water consumption at the mine site. Water accounting and reporting based on the ICMM framework promotes greater transparency and improves social and environmental performance of a mine.Item Open Access MODELING COMPLEX RELATIONSHIPS IN GEOMETALLURGICAL VARIABLES: ENHANCING METHODS WITH ACCEPTANCE-REJECTION AND HIERARCHICAL GAUSSIAN CO-SIMULATION(Nazarbayev University School of Mining and Geosciences, 2024-04-16) Kuanyshev, ShingiskhanResource estimation is the basis of efficient and sustainable mining. Accurate mineral resource estimation is critical to optimizing mine planning, minimizing waste, and ensuring the economic viability of mining operations. Traditionally, resource estimation focused primarily on grade, the concentration of valuable minerals in ore bodies. However, the evolving complexity of modern mining requires a holistic approach that includes not only the grade but also the geometallurgical properties of the ore. Geometallurgical properties, which include attributes such as mineralogical composition, texture, and work index, play a key role in shaping mining operations. Understanding and modeling these properties is essential to unlocking the full potential of mineral deposits. In the context of mining, geological complexity often leads to complex non-linear bivariate relationships between different attributes of ore bodies. These relationships can pose significant challenges for resource modeling, as traditional methods such as Principal Component Analysis (PCA) and Minimum/Maximum Autocorrelation Factor (MAF) are ill-suited to handle such complexities. These methods are inherently linear and may fail to capture the nuanced interactions and dependencies within geologic datasets. This research paper presents a new approach to address the complexity of resource estimation in mining, particularly when dealing with non-linear bivariate relationships between geometallurgical properties. The proposed method combines the accept-reject method with hierarchical sequential Gaussian co-simulation. This approach enables the careful modeling of complex relationships (non-linearity) within geological data, leading to more accurate resource estimates and better-informed mining decisions. A case study is presented in which the acceptance-rejection method with hierarchical sequential Gaussian co-simulation is applied to the modeling of two geometallurgical properties, recovery and chalcopyrite. The study shows how this innovative approach increases resource estimation accuracy by capturing non-linear dependencies and spatial variability between these two variables. Due to the hierarchical nature of geological data, the method adapts to different scales of variability, resulting in more realistic and practical resource models. The findings of this research not only highlight the importance of integrating geometallurgical properties into resource estimation, but also provide a valuable solution for solving complex nonlinear bivariate relationships in geostatistical analysis of other regionalized variables. This approach has the potential to revolutionize resource modeling practices in the mining industry, leading to more sustainable, efficient, and economically viable mining operations. As mining continues to face evolving challenges and requirements, it is essential to incorporate advanced techniques such as the accept-reject method with hierarchical sequential Gaussian co-simulation to exploit the full potential of the Earth's mineral resources.Item Open Access APPLICATION OF FAST RESERVOIR SIMULATION CAPACITANCE-RESISTANCE METHOD TO PREDICT THE HOT WATER FLOODING PERFORMANCE(Nazarbayev University School of Mining and Geosciences, 2024-04-12) Almatkyzy, MoldirA range of methods is available to assess a reservoir performance. Development and application of fast methods to evaluate the performance of a recovery method and provide a general picture of injectors/producers connectivity is critical to manage a reservoir. Capacitance Resistance Model (CRM) is a useful tool for improving real-time flood management, as it allows rapid modeling and simulation of gas and water flood recovery processes. The CRM approach is based on signal processing methods in which injection rates are accepted as input signals and production flow rates are considered as reservoir response or output signals. The model offers key advantages, including simplicity, immediate results, and optimal performance even with minimal initial data. Over recent years, enhancements in CRM have established it as a reservoir management tool, enabling essential tasks like history matching of production data, forecasting production rates, scheduling injection rates, detecting injection leakage, and estimating fracture distribution (Sayarpour, 2008). In this study, we expanded the application of CRM to predict the behavior of hot water injection processes. Systems identification is applied for history matching using only injection/production data from commercial simulator to characterize the reservoir models where injection of hot water was applied, evaluating interwell connectivities and time constants. Four case studies were developed with two different injection fluid types. These included a homogeneous model with a five-spot well pattern (Case 1), models featuring high-permeability streaks (Case 2 and 3), and a heterogeneous reservoir model (Case 4). In these cases, bottomhole pressures and production rates remained constant, while injection rates fluctuated over the simulation period. The first three cases were analyzed to predict reservoir performance analytically under specific conditions for homogeneous scenarios. The highest calculated average error was observed during Case 2 for both total liquid production and oil production rates (10.84% and 11.79%, respectively), while the minimum average error values were found in Case 4, with values of 6.50% for liquid rates and 5.76% for oil production rates. In all cases, the results of the developed models exhibited satisfactory agreement with those of a grid-based commercial simulator. We considered these hypothetical cases where modifications were applied to generate a more reliable evaluation of interwell connectivity and time constants, and used the R-squared value of the model as a fitting parameter for history matching processes. This approach, applied across multiple cases, yielded excellent evaluations of both reservoir performance and well connectivity.Item Open Access LABORATORY INVESTIGATION OF CRYOFRACTURING POTENTIAL TO STIMULATE GEOTHERMAL RESERVOIRS IN KAZAKHSTAN(Nazarbayev University School of Mining and Geosciences, 2024-04-19) Begaliyev, DastanFollowing the adoption of the Concept of Transition to Green Economy, Kazakhstan's renewable energy sector continues to expand. Shift to renewable energy is of key importance since it will help lower the amount of greenhouse gases which are emitted. The geothermal energy, including the HDR (Hot Dry Rocks), is a renewable source of power, though the low permeability is a challenge. EGS (Enhanced Geothermal Systems) are a promising technology which can widen geothermal energy use by creating reservoirs through stimulation practices, solving permeability problems in HDR formations. Methods like hydraulic fracturing and thermal stimulation have been suggested by researchers to enhance the productivity of hot dry rock reservoirs, however, these can cause environmental pollution and formation damage and not applicable in dry countries like Kazakhstan because of water scarcity. One way of solving the problem of water-related issues in Enhanced Geothermal Systems (EGS) is to use cryogenic fracturing, which with liquid nitrogen is not only efficient, but also environmentally friendly. This research project entails investigation of influence of elevated temperature with LN2 cooling on granite strength as a destructive and non-destructive experiments. There were selected 2 different granites from the outskirts of Akmola region to make comparative analysis. The analysis was made through 16 destructive experiments with unconfined compression and Brazilian tests, as well as by 2 non-destructive measurements with the help of XRD (X-ray diffraction) and CT Scan. The tests were conducted to identify the structural modifications and the mechanical behaviour of the granites affected by the thermal shock process performed in the cryogenic environment. The variable temperatures with LN2 treatment during the compression and Brazilian tests were applied. The analysis revealed several key findings. A compression and Brazilian tests showed that the breaking strength gradually diminished with the rise of temperature and LN2 cooling while the granite was heated, leading to the conclusion that the granite's strength is reduced. It was shown that Young's modulus decreased with increasing thermal shock, while there is a positive correlation between Poisson's ratio and thermal shock. Even though both granites showed similar incrementing trends regarding damage factor curves, granite 1 exhibited a more affected response after heating and LN2 fracturing, and it was more damaged compared to granite 2 in both the compressive and Brazilian tests. Therefore, it can be inferred that granite 1 achieved superior results compared to granite 2.Item Embargo CHARACTERIZATION AND PERFORMANCE ASSESSMENT OF A NOVEL NIO-FE3O4-POLYTHIOPHENE NANOCOMPOSITE FOR ASPHALTENE PRECIPITATION INHIBITION(Nazarbayev University School of Mining and Geosciences, 2024-04-19) Serikbay, MardanPrecipitation and deposition of asphaltene represents a significant challenge in the oil industry. Nanomaterials are considered as proper candidates for asphaltene adsorption and precipitation owing to their exceptional physical and chemical features. In this dissertation, first, a novel NiO-Fe3O4-Polythiophene nanocomposite (NC) was characterized using various advanced analytical methods to ensure its authenticity. X-ray diffraction (XRD) was used to determine the crystallite size and explore structures of the NC. Scanning electron microscopy (SEM) was used to investigate surface morphology and assess the particle size of the NC qualitatively. Fourier transform infrared spectroscopy (FTIR) methods was used to identify functional groups and elemental bonding of the NC. Brunauer-Emmett-Teller (BET) method was used to determine surface area of the NC. Thermogravimetric analyzer (TGA) was used to explore thermal stability of the NC. Using the XRD data the crystallite size was determined 33.2 nm. The particle size of the NC ranges from 60 to 400 nm based on SEM images, and surface area of the NC was determined 55.83 m2/g using the BET test data. TGA analysis revealed that the NC is thermally stable with a negligible mass loss under reservoir conditions (80°C). To assess efficacy of the novel NC for adsorption and inhibition of asphaltene, UV-spectroscopy technique was used to determine Asphaltene Onset Point (AOP) in presence and absence of the NC and then supernatant obtained from TGA analysis was used for adsorption kinetics isotherm modeling. Adsorption kinetics isotherm modeling was done using the Langmuir (R2 = 0.98) and Freundlich (R2 = 0.95) isotherm models. The experimental data matched well both models which suggests monolayer and multilayer adsorption behavior for adsorption of asphaltene onto the surface of the NC. A maximum adsorption capacity of 1.116 mg/m2 was obtained for the NC. TGA analysis confirmed that oxidation of virgin asphaltene started at around 400-450℃; while oxidation of 5,000 ppm sample with NC started at around 350℃. The NC has catalyzed oxidation of the asphaltene. An optimum NC concentration of 0.3 wt% was obtained and an AOP shifting from 40% to 48% volume of n-heptane was observed for the optimum concentration. The outcomes prove that, the novel NC is an effective nano-inhibitor for asphaltene under laboratory conditions.Item Embargo CHARACTERIZATION AND PERFORMANCE ASSESSMENT OF SIO2-KCL-XANTHAN NANOCOMPOSITE AS A NOVEL NANO-ASPHALTENE PRECIPITATION INHIBITOR UNDER LABORATORY CONDITIONS(Nazarbayev University School of Mining and Geosciences, 2024-04-18) Kaliolla, KemelkhanIn this experimental research work, efficiency of SiO2-KCl-Xanthan nanocomposite (NC) as a nano-inhibitor for adsorption and removal of asphaltene from a synthetic crude oil medium was investigated. The NC has been used as an EOR and smart drilling fluid agent with impressive results. This was the motivation behind this research work. The first phase of the research involved extraction of asphaltene from a West Kazakhstani heavy crude oil and characterization of both asphaltene and the NC. Different state of the art analytical techniques including scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller or BET, X-ray diffraction (XRD), and thermogravimetric or TGA were used for NC. This was to ensure authenticity and functionality of the NC. The NC has a spherical structure with particle sizes ranging from 30 to 300 nm determined using SEM analysis. The crystallite size was calculated 41 nm using the XRD data. The surface area of the NC was determined 31.95 m2/g using the BET method. TGA analysis showed that the NC did not experience any significant mass loss for a typical reservoir temperature (80°C) and it is thermally stable for oilfield applications. Based on the FTIR spectra, presence of organic functional groups of phytochemicals on the NC was identified indicting successful synthesis of the NC. The last stage was to assess the efficiency of the nano-inhibitor by determining the Asphaltene Onset Point (AOP) using UV-vis spectroscopy technique and asphaltene adsorption kinetics isotherm modeling using the supernatant obtained from TGA analysis. TGA analysis confirmed that oxidation of virgin asphaltene started at around 400 to 450℃. While, oxidation of 5,000 ppm sample with NC started at around 280℃. The NC has catalyzed oxidation of the asphaltene. Adsorption kinetics isotherm modeling was done using the Langmuir (R2 = 0.98) and Freundlich (R2 = 0.82) isotherm models. The experimental data matched well both models, which suggests monolayer and multilayer adsorption behavior for adsorption of asphaltene onto the surface of the NC. A maximum adsorption capacity of 1.33 mg/m2 was obtained for the NC. The novel nano-inhibitor shifted the AOP by 5% and the optimum concentration of NC was determined 0.3 wt%. Overall, the NC showed promising inhibitory performance under laboratory conditions.Item Open Access POLYMER FLOODING IN UZEN FIELD: A SIMULATION STUDY TO DESIGN AND ANALYZE THE EFFECT OF OPERATIONAL PARAMETERS(Nazarbayev University School of Mining and Geoscience, 2024-04-18) Mukhtarov, AibekEnhancing oil recovery in mature oil fields poses a considerable challenge within the oil and gas sector. Despite the prevalent application of waterflooding techniques, significant amount of oil often remains unrecovered. This study focuses on enhancing oil recovery in the Uzen field, through the implementation of polymer flooding alongside hot water flooding and hot polymer flooding methods. Numerical simulations are employed to evaluate the influence of operational parameters on the efficacy of polymer flooding. Key parameters under scrutiny include the polymer injection rate, duration of flooding, and polymer concentration. The main objective of this investigation is to devise an optimal set of operational parameters specific to the Uzen field, thereby maximizing the effectiveness of polymer flooding. The outcomes derived from the numerical simulations reveal that the most favorable polymer injection rate is 140 m3/d, with an optimal polymer flood duration of 20 years, and an optimal polymer concentration of 2500 ppm. Characterized by a high water cut, the Uzen field represents a prime candidate for the implementation of polymer flooding as a tertiary recovery strategy. By conducting comprehensive experimental and simulation studies, different operational parameters were designed and evaluated. Practical recommendations were provided to enhance oil recovery within the Uzen field, based on an integrated research approach.Item Restricted EVALUATION OF FLUID/FLUID INTERACTIONS DURING LOW SALINITY WATER FLOODING.(Nazarbayev University School of Mining and Geosciences, 2024-04-10) Villero Mandon, Jose DanielLow-salinity water flooding/smart water flooding (LSWF/SWF) involves injecting water with an altered composition to modify the equilibrium between rock and fluids within porous media, particularly for enhanced oil recovery (EOR) due to improved extraction efficiency. This technology offers significant advantages, being environmentally friendly and often more economically efficient. LSWF/SWF has been shown to increase recovery factor (RF) between 6% and 20% in oil-wet rocks, making it an appealing option, especially for sandstones with low clay content, which tend to be water-wet. While most studies focus on rock/fluid interactions as the primary mechanism, this study explores the effects of LSW mechanisms on the brine/oil interface alongside rock surface interactions and the synergistic effects of a hybrid EOR approach. Initially, ions were classified into three groups: monovalent cations (Na+, K+), divalent cations (Mg2+, Ca2+), and anions (SO42-). Ten different brines with varying ionic compositions and strengths were then prepared and screened based on interfacial tension (IFT), microdispersions generation, and rheological properties measurements to identify the optimal scenario for LSWF/SWF and observe the effects of different concentrations (7500 and 5000 ppm) on fluid/fluid interactions. The best option identified was further investigated in core flooding experiments conducted at 11500 ppm, 8500 ppm, and 1000 ppm to evaluate LSW/SWF flooding under different conditions and design techniques. Key findings include the observation that a single ion configuration brine approach may be not as as representative of interactions in brine/oil interface. IFT is highly dependent on asphaltene content, with lower asphaltene content yielding better results in IFT with more complex brines. Salinity was found to increase IFT by approximately 1 mN/m per 1000 ppm. As the anions in the salts increased, the interface became more viscoelastic and resilient to snap-off (capillary forces drive the wetting phase to infiltrate, displacing the initial nonwetting phase as presented by Li & Yao 2023 ) occurrence, while changes in salinity had minimal impact on the storage modulus. The microemulsion volume fraction increased depending on the asphaltene content, with an increasing colloidal instability index (CII) directly impacting the volume of emulsions. Overall, fluid/fluid interactions were found to be more related to LSWF/SWF in different oil samples with different content of asphaltenes and different compositions. For core-flooding, comparingcores with same rock type, but different fluid injection, an additional 4.1% Original Oil in Place (OOIP) was achieved due to improved fluid/fluid interactions, with tertiaty flooding recovering an additional 1.8% OOIP, representing an efficiency improvement of roughly 15% compared to NaCl alone, solely attributed to an enhanced interface. Low salinity water below the critical salinity concentration (CSC) resulted in an additional 0.7% OOIP recovery, representing 3.55% of residual OOIP. This methodology proved to be innovative and feasible for fluid/fluid interactions and can be extrapolated for rock/fluid interactions.Item Restricted PREDICTIVE MODELING OF PROPPED FRACTURE CONDUCTIVITY IN SHALE GAS RESERVOIRS(Nazarbayev University School of Mining and Geosciences, 2024-04-17) Yegeubayeva, AlinHydraulic fracturing is a well completions technique that induces a network of flow channels in a reservoir. These channels are characterized by fracture conductivity, a measure of how easily a liquid or gas flows through the fracture. Fracture conductivity is influenced by several variables including proppant size, proppant concentration, and hydraulic fracture characteristics. The purpose of this research is to present a unique process that incorporates machine learning neural networks in order to predict the fracture conductivity of multi-stage fractured horizontal well in shale gas reservoirs. To accurately predict fracture conductivity using fracture parameters such as width, height, length and orientation, a robust model is necessary. In this study, predictive ability of Multilayer Perceptron algorithm was used in forecasting fracture conductivity. The findings revealed the R-squared value of 0.82, which show a good correlation of these values with the previously conducted researches. Secondly, during validation of algorithm, CMG calculated fracture conductivity at 4.6 md.ft, although the machine learning model came closest at 4.43. Overall, values and other input variable parameters are near, indicating good model performance. Lastly, enhancing the cumulative gas output has been shown to be significantly aided by the process of fine-tuning fracture parameters, which are fracture length, height, and width, inside the CMG program. The obtained results can be used as references in the future examination of parameters that affect fracture conductivity.Item Embargo SYNTHESIS AND CHARACTERIZATION OF NATURAL SURFACTANT FOR ENHANCED OIL RECOVERY APPLICATION(Nazarbayev University School of Mining and Geosciences, 2024-04-12) Tukhfatova, AibikeEnhanced Oil Recovery (EOR) techniques rely on chemical agents, but the excessive utilization of synthetic chemicals presents environmental and economic issues. Natural surfactants have become known as a viable option for Chemically Enhanced Oil Recovery (CEOR) processes. These natural agents are being acknowledged for being eco-friendly, less harmful, and cost-efficient in comparison to conventional synthetic surfactants. However, ongoing research and investigation are necessary to determine the extent to which natural surfactants can be effectively utilized across a range of conditions. The study seeks to illustrate that surfactants derived from neem powder possess the capability to function as a viable replacement for conventional surfactants in oil recovery procedures. The research commences by creating a surfactant sourced from sustainable materials, mainly neem powder and olive oil, in conjunction with sodium hydroxide (NaOH). The synthesis procedure entails an infusion of neem powder into olive oil, subsequently followed by the saponification reaction with NaOH. The resultant surfactant presents the benefit of being environmentally friendly and economically feasible. In this research, the efficacy of the natural surfactant was evaluated through experimental assessments, including measurements of interfacial tension (IFT) and core flooding experiments. After confirming the natural surfactant's properties through FTIR, SEM, and EDS analyses, solutions of the surfactant were formulated at different concentrations. These concentrations ranged from 1 to 6 wt% in deionized water (DIW) and from 0,5 to 5 wt% in brine. The IFT findings indicated that the optimal critical micelle concentration (CMC) for the natural surfactant was determined to be 4,0 wt% in deionized water (DIW) and 0,9 wt% in brine. The brine-based surfactant solution reached a minimum IFT of 1,4 mN/m at the CMC point. The analysis investigated the influence of temperatures ranging from 35 to 55°C on the surfactant's efficacy, showcasing its consistent performance across the temperature range. This study offers a valuable understanding of the possibilities of utilizing natural surfactants in EOR and underscores the necessity for additional research to enhance their effectiveness in practical applications.Item Restricted AN INNOVATIVE TRUNCATED GAUSSIAN COLLOCATED CO-SIMULATION APPROACH FOR STOCHASTIC MODELING OF GEOLOGICAL DOMAINS(Nazarbayev University School of Mining and Geosciences, 2024-04-17) Adoko, Collins GogoeIn order to get a precise assessment of the quantity of mineral resources contained inside a deposit, it is necessary to create a comprehensive model that encompasses its geological domains. Efficient modeling of these geological domains (rock units, alteration types, and mineralization zones) is vital as they often serve as the mineralization controls of the deposit. Deterministic modeling tools such as wireframing make geological assumptions, especially in the intervals between drill holes, and so may yield incorrect conclusions about the complexity of the deposit in such intervals. Moreover, the uncertainty of rock units in unsampled places cannot be quantified using these deterministic modeling techniques. As such, methods for stochastic modeling are typically favored. The two most often used stochastic approaches that are better suited to address these shortcomings of the deterministic modeling of geo-domains are sequential indicator simulations and truncated/plurigaussian Gaussian simulations. The Truncated Gaussian simulation is an essential simulation approach for defining complicated geometry of rock units because it can accurately represent the spatial connection between rock units and quantify their uncertainty. However, long-scale geological structures like veins, faults, and fractures tend to be loosely modeled when employing this approach; in order to prevent this inaccuracy, soft data such as deterministic interpretive geological models can be used. In this project, the variability of rock units in the subsurface is assessed and the uncertainty in their occurrences in a gold deposit which is vein-dominated is quantified using the Truncated Gaussian simulation. A new method for modeling the rock units—in particular, the long-scale geological structures (veins in this case) is provided. The method involves integrating the conventional Truncated Gaussian simulation with a collocated co-simulation algorithm that is based on the inclusion of a local and global correlation coefficient parameter. The realizations are conditioned to data from drill holes and a machine learning algorithm-generated collated interpretive geological model. A number of realizations, 100 in total, are produced from both the local and global correlation co-simulations. The results show the practical spatial representation of the veins and other rock units as validated by the information from drill holes and also appropriately quantify the uncertainty associated with their occurrences compared to the conventional Truncated Gaussian.Item Restricted QUANTITATIVE ASSESSMENT OF THE IMPACT OF MINING ACTIVITIES ON THE ENVIRONMENT IN THE ULYTAU REGION USING GEOSPATIAL APPROACH(Nazarbayev University School of Mining and Geosciences, 2024-04-18) Yessengossov, ZhangirThe topic of "Quantitative assessment of the impact of mining activities on the environment in the Ulytau region using geospatial approach" was chosen due to the urgent need to understand and quantify the environmental impact of mining activities in the Ulytau region. While geospatial approach provides a systematic and quantitative method for analyzing environmental impacts of mining activities, which can be helpful for effective environmental management and sustainable resource extraction. The objective of this thesis is to conduct a comprehensive quantitative assessment of the impact of mining activities on the environment in the Ulytau region using a geospatial approach. This includes quantification of mining activities in the region, estimation of area impacted by the mining activities, and assessment of its impacts on the local environment. Also, it includes produced maps with mining locations. The research approach involves understanding of the negative impacts of mining on the environment from the literature, and involves understanding of tools utilized for geospatial technology to monitor and analyze the Ulytau region. Also, application of geospatial approach includes utilization of Google Earth and QGIS softwares for satellite imagery, and Excel for data quantification. Moreover, besides providing the methodology for geospatial assessment, the thesis proposes international practices and experience of other countries and considers regulatory framework. The quantitative analysis on 51 mining activities has shown notable increase in the mining activities in the Ulytau region. During the study period from 2004-2011 to 2023, it shows an increase from 91.133 km2 to 114.874 km2, or 26.1%, or 23.742 km2 in absolute values. These conclusions show the importance of a geospatial approach that can assist in quantification of areas affected by the mining activities, and it can be implemented for sustainable mining practices and effective environmental management strategies to mitigate negative impacts of mining. It shows the need for implementation of modern technologies associated with the Fourth Industrial Revolution, since it can assist in sustainable and environmentally friendly business. For future research, it is recommended to continue utilizing geospatial approaches for monitoring and assessment of mining activities. Additionally, research efforts should focus on exploring other available remote sensing technologies, and it should include application of machine learning, and artificial intelligence to improve data analysis capabilities. Also, further research should be done assessing existing environmental regulations and enforcement mechanisms. Moreover, further research should include access to more comprehensive and detailed data sources to enhance accuracy and depth of analysis.Item Embargo NUMERICAL INVESTIGATION OF FAULT GOUGE MATERIAL (FGM) MECHANICAL BEHAVIOR UNDER THE INFLUENCE OF PORE PRESSURE AND LOADING CONDITIONS(Nazarbayev University School Of Mining and Geosciences, 2024) Yaqoob, MuhammadThis research study presents a numerical analysis of the mechanical behavior of fault gouge materials (FGMs) using the finite element method (FEM) within the Abaqus computational analysis environment (CAE). The mechanical properties of fault zones are greatly influenced by fault gouge materials, which are fine-grained materials located inside fault planes. The mechanical behavior of FGM toward pore fluid pressure plays a crucial role in Carbon Capture and Storage (CCS) projects, which include the sequestration of CO2 inside geological formations. Previous research has shown the important role of fluid pore pressures in commencing fault displacement, which may either reduce or increase fault stability. Pore pressure fluctuation plays an important role in maintaining fault stability in completely saturated FGMs. The purpose of this thesis is to analyze the behavior of fluid-saturated fine-grained materials (FGMs) under both normal and shear loading situations using Abaqus Finite Element Method (FEM) analysis. The study intends to address the limitations of currently available prediction models and contribute to the advancement of geomechanics knowledge in the context of FGM. The comparative analysis evaluates the influence of pore pressure on the Fault Gouge Material (FGM) in both models. The FGM simulation findings indicate that the models without pore pressure exhibit slightly greater deformation compared to the models with pore pressure. However, while considering the elastic analysis, it is shown that the FGM demonstrates a greater degree of deformation when subjected to pore pressure under normal loading conditions.Item Embargo INVESTIGATION OF CLAY SWELLING PROBLEM DURING THERMAL OIL RECOVERY IN EAST MOLDABEK OIL FIELD, KAZAKHSTAN(Nazarbayev University School of Mining and Geosciences, 2024-04-15) Yesmukhambet, MadiIn sandstone oil fields like those in Kazakhstan, steamflooding is a vital technique for enhancing oil recovery. However, a significant challenge arises from the swelling of clay minerals in reservoirs, causing permeability damage and impeding oil production. This thesis investigates clay swelling phenomena in sandstone oil reservoir in Kazakhstan, where smectite-illite clays constitute 40% of the reservoir rock. The scope of work encompasses a comprehensive examination of clay swelling behavior and its impact on permeability degradation by conduction a set of static and dynamic tests. Key objectives include study of temperature and salinity effect on clay swelling index and permeability reduction during dynamic coreflooding tests, determination of critical swelling concentrations and flow rates under different temperature and salinity regimes. The obtained results showed that at low salinity and high temperature conditions the clay swelling increases leading to serious permeability impairment. The results showed that at high salinities (4920-2000 mg/L) the swelling rate is low while at salinity range from 2000-0 mg/L is relatively higher. During static swelling test the highest expansion of clays of 2.25 times increase in volume was experienced at 200℃ and DW saturation. The CSC increases with temperature leading to higher swelling degree of clays. Increasing temperature and decreasing salinity leads to high permeability impairment. It was found that at critical swelling concertation (CSC) of 2.5NK no clay swelling was observed and permeability did not change at any temperature with an average value of 6.7mD. Generally, the critical flow rate drops by 0.1 cc/min when salinity lowers. The maximum permeability drop by 73.3% was observed at 150℃ and DW flooding. The comparison between static and dynamic results revealed that clay swelling degree is consistent between static and dynamic tests. The findings of this study will enhance our understanding of clay swelling under conditions resembling those of steamflooding, encompassing changes in salinity and temperature. Moreover, these results could inform the development of potential solutions to address and alleviate clay swelling issues in Kazakhstan's oil field.Item Restricted EFFECT OF AIR CONTENT, TEMPERATURE, AND SALINITY ON POLYMER DEGRADATION(Nazarbayev University School of Mining and Geosciences, 2024-04-16) Yerniyazov, DaniyarWith rising global energy demands, the oil and gas sector is tasked with optimizing output from mature oil fields. These fields, once powered by natural pressures for primary production, now yield less due to the limitations of traditional recovery methods like gas and water drives. This necessitates a shift towards secondary and then to enhanced oil recovery (EOR) techniques for better efficiency and economic feasibility. Polymer flooding, a key EOR strategy, improves recovery using water-soluble polymers to enhance water viscosity, addressing inefficiencies such as fingering and channeling within reservoirs. While successfully boosting oil recovery worldwide, this method encounters obstacles including polymer degradation, adsorption issues, and reduced effectiveness, mainly due to the challenging conditions within reservoirs such as varying oxygen levels, temperatures, and salinity. These environmental factors critically affect the performance and success of polymer flooding. This research investigates the impact of adding specific ions to brine on polymer viscosity and stability in oil recovery processes, particularly polymer flooding. The whole experimental part of this research was divided into three steps, which are rheology test, thermal stability test and oil displacement test. During the rheology test, the difference in viscosity values of polymer solutions prepared on different brine compositions was analyzed. On the thermal stability test, the effect of air and nitrogen injection, effect of additional ions on the ability of polymer to withstand the higher temperature for the long period between 14 and 60 days can be observed. Finally, oil displacement test was conducted, with the optimized brine composition for polymer preparation, to see how the optimization of brine composition improves the recovery. It was found that while calcium chloride (CaCl2) negatively affects polymer viscosity, sodium sulfate (Na2SO4) enhances it, especially in the presence of other ions, indicating that overall salinity is a crucial factor in polymer behavior. Notably, Na2SO4 protects polymers from oxygen-induced degradation, suggesting that oxygen removal, which requires additional facilities, might not be necessary. Long-term thermal stability tests showed that polymers with added Na2SO4 are more stable and less sensitive to oxygen presence. The optimal combination of 4 doses of Na2SO4 and 2 doses of CaCl2 was identified, leading to the most stable polymer with the highest viscosity and lowest degradation. This optimal solution demonstrated improved oil recovery in displacement tests, with 4.6% of additional recovery per each injected PV, compared to 2.9%/PV for the polymer solution prepared on standard CSW, although, total recovery factor at the end of polymer flooding stage was 90% of OOIP. It happens due to negatively charged sulfate ions reducing attraction between the polymer and formation rock walls, thus maintaining polymer structure stability. These findings highlight the potential of optimized ion concentrations in enhancing polymer flooding efficiency.Item Restricted IMPLICATIONS FOR PRIMARY DEPLETION OF CARBONATE SLOPE DEPOSITS FROM TENGIZ OIL FIELD AND RESERVOIR CHARACTERIZATION BASED ON AN OUTCROP ANALOGUE(Nazarbayev University School of Mining and Geosciences, 2024-04-19) Nadirkhanova, DinaraThis study examines the Paleozoic platform outcrop in the Bolshoi Karatau as an analogue for the giant oil fields in the Pricaspian basin, with a focus on the carbonate distal slope-basin deposits at the Akuyuk section. A detailed sedimentary log (39.6 m thick) reveals a predominance of grainstone lithofacies, consisting mainly of micro- to mm-scale skeletal fragments, microfossils. Notably, occurrences of rugose corals and cephalopod fragments were located mostly on the top of the individual beds, which are settled down. Microfacies analysis divides the section into biosparite (grainstone) and biomicrite (packstone), predominantly comprising microfossils (foraminifers, calcipheres), peloids, and occasionally intraclasts. Deposition occurred in a shallow marine environment and transported through turbidites to the lower slope. Gamma-ray spectrometry analysis indicates very low radioactivity, suggesting predominantly pure carbonates and a marine depositional setting. The proposed main depositional environment is a proximal lobe with mostly amalgamated turbidites, occasionally with muddier parts (packstones). Observations of not full Bouma sequences (only Ta or Ta and Te) (Bouma et al. 1962), mainly Ta (high concentrated flow without any visible sedimentary structures), and chertified trace fossils (thalassinoides) suggest episodic possible Te preservation. Thalassinoides accumulation in soft sediments obscures sediment appearance. The study conducted six scanlines primarily in the lower part of the section, revealing a predominance of extensional fractures filled with calcite, perpendicular to bedding, and stylolites parallel to bedding, indicative of tectonic influence. Analysis of fracture characteristics such as aperture, height, and spacing showed distributions skewed towards smaller values, because of measurement limitations for smaller fractures. The mode and standard deviation for aperture were 0.15 mm and 1.6 mm, respectively, while for height, they were 0.16 m and 0.38 m. Relationships between fracture parameters indicated independence, suggesting complex control factors. The association of veins with faults or folds suggests formation during mountain-building events, contributing to the dynamic geological history of the study area. Further analysis reveals a consistent pattern of densely spaced fractures within individual beds, indicating a strong influence of each layer's mechanical properties. However, variability in fracture heights and spacing suggests structural complexity. While dense spacing and bed confinement are prevalent, and variations highlight the nuanced impact of mechanical stratigraphy on fracture propagation. In a primary depletion analytical model, outcrop sedimentological and fracture data serve as primary inputs, facilitating fluid transport between the matrix and fractures. This model examines how variables such as Vf/Vm and kf/km (sensitivity analysis) affect reservoir depletion, emphasizing rapid fracture depletion compared to constant matrix pressure. Variations in both volume coefficients and permeability coefficients significantly influence the flow behavior in natural fractured reservoirs: higher permeability coefficients lead to faster rate decline, and lower volume coefficients enhance this effect, promoting a rapid transition to fracture matrix flow. The integration of sedimentological logging, microfacies analysis, gamma-ray spectrometry, fracture analysis, and analytical primary depletion modeling sheds light on the importance of field data in understanding fluid flow within naturally fractured reservoirs. These findings offer valuable insights for enhancing reservoir modeling.Item Embargo APPLICATION OF NATURAL POLYMER IN ENHANCED OIL RECOVERY(Nazarbayev University School of Mining and Geosciences, 2024-04-15) Serikov, GalymzhanWith the recent intereset in the chemical EOR application, polymer flooding projects are revieving more attention. However, currently polymer injection may lead to serious environmental problems in the future due to their synthetic nature. The following thesis work evaluates the application of three natural polymers of Xanthan gum, Welan gum, and Beta Vulgaris for EOR application. General workflow consists of polymer screening, FTIR and SEM characterization, rheological analysis under elevated temperature and salinity conditions and core flooding experiments. FTIR and SEM characterization have shown major hydroxyl functional groups related to saccharide rings confirming nature of the polymers. Rheoligcal studies showed that Xnathan gum is more tolerant to temperature and salinity changes. Welan gum is highly tolerant to temperature changes and tend to loose rheological properties at elevated salinity ranges. Beta Vulgaris rheology have shown poor results on both salinity and temperature. Core flooding results showed that recovery factor increase from Xanthan gum injection is around 30% after waterflooding. Welan gum and Beta Vulgaris showed lower results of 15% and 10% addition oil recovered. Overal, natural polymers are considered as a more sustainable and eco-friendly option compared to the standard synthetic polymers. This research supports an EOR strategy aimed at reducing environmental impact of polymer floodingItem Embargo ENHANCING RESOURCE MODELLING OF TAILINGS STORAGE FACILITIES THROUGH FACTORIAL GEOSTATISTICS(Nazarbayev University School of Mining and Geosciences, 2024-04-18) Tileugabylov, AidynIn the modern economy, mining is essential for providing the chemicals needed to produce daily commodities. Due to technological constraints, significant minerals that were not effectively recovered during the initial extraction and processing steps are typically found in tailings in residual amounts. However, it is now essential to investigate the accumulated tailings deposits to reprocess them for an additional economic benefit due to the large decline in cut-off grade over the last few decades along with advancements in mineral processing techniques. However, traditional methods of mineral resource estimation struggle with the modelling of multiple cross-correlated variables that are present inside of tailings storage facilities. More precisely, traditional methods of cosimulation struggle with the inference of cross-covariance and solving the cokriging matrix system. This study proposes a factor-based algorithm to model cross-correlated geochemical variables based on the forward and backward MAF transformations that would eliminate two issues associated with traditional methods of modelling. The performance of the algorithm is applied to a real case study of Cu-Au tailings storage facility and is compared with the outcome of traditional cosimulation approach. Consequently, the proposed algorithm presents results similar to the ones obtained from the traditional cosimulation in terms of model validation and reproduction. Jackknife validation has been the primary model validation technique employed in this study along with the accuracy plot, and statistical reproduction. The mineral resource estimation of a tailings storage facility was conducted, and the results show promising metal quantity, mean grade and tonnage for most of the elements.