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02. Master's Thesis

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Open Access
ADOPTION OF SPACE LASER BEAM ROCK ANALYSIS TECHNOLOGY FOR TERRESTRIAL MINING APPLICATIONS WITH A FOCUS ON BLOCK CAVING MINING SYSTEMS: CONCEPTUAL DEVELOPMENT
(Nazarbayev University School of Mining and Geosciences, 2022) Sadyrbayev, Bakytzhan
The block caving mining system is the most economical underground mining system known today, and its popularity in the mining industry continues to increase. The block caving mining system can be described as the preferred mining system of the future, as it lends itself to automation. One of the most laborious tasks in block caving operation management is monitoring dilution at drawpoints. This task is currently manually handled by a geologist. Monitoring dilution manually at drawpoints is labor-intensive, time-consuming, and depends on the experience of geologists. In 2011 the National Aeronautics and Space Administration (NASA) introduced a laser beam rock analysis system via ChemCam on its Curiosity rover deployed on Mars. This device based on Laser-Induced Breakdown Spectroscopy (LIBS) heats the rock to about 10 000°C by the infrared laser beam and then analyzes laser plasma created from the molten rock. The technology is currently enhanced and is deployed on Mars via SuperCam on the Perseverance rover which is landed on Mars on 18th February 2021. It is hypothesized that the LIBS can be adopted for terrestrial underground mining applications for dilution monitoring at drawpoints in block caving operations. This application will increase the precision of the measurements, remove the labor-intensive and time-consuming use of geologists at drawpoints, reduce the block caving mining system's costs and increase the safety of the operation. In this thesis, a conceptual model for the application of LIBS space technology for dilution monitoring via a mobile robot is developed.
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ANISOTROPIC INVERSE DISTANCE WEIGHTING (IDW) METHOD: AN INNOVATIVE TECHNIQUE FOR RESOURCE MODELING OF VEIN-TYPE DEPOSITS
(Nazarbayev University School of Mining and Geosciences, 2022-04-20) Ongarbayev, Ilyas
The geological model is integral evaluation of natural resources. The traditional explicit geological modeling approach has been used in the industry for a long time. However, due to its time-consuming nature and inflexibility, implicit geomodelling has emerged as an alternative. Implicit modeling approaches are based on mathematical algorithms, which automatically build the geological model, thereby taking on all arduous work. In this respect, the authors propose a previously unused for modeling of categorical variables in anisotropic geological conditions, the Anisotropic Inverse Distance Weighting (IDW) method. The underlying concepts of how the proposed method works are comprehensively introduced in the methodology section. The Anisotropic IDW is explicitly oriented for modeling anisotropic domains, and the variogram analysis is vital for the proposed method. The Anisotropic IDW produces acceptable results, and to evaluate its performance, the Anisotropic IDW was compared to widely used in the industry Indicator Kriging (IK) and traditional IDW. The experimental part was implemented on synthetic and real case studies. The synthetic dataset represents a 2D modeling of two geological domains, where the modeling methods estimate the potential ore and waste domains. The synthetic case study was conducted to evaluate the capabilities of the proposed methodology compared to traditional IDW and IK and determine which one of the methods is more suited for geomodelling of veins in anisotropic conditions. The real case study was considered in 3-dimension and using the borehole assays from a vein-type gold deposit in Kazakhstan. The real case study was conducted to show that the proposed methodology might be successfully applied in real conditions. Furthermore, resource estimation was performed to compare modeling methods more comprehensively. As for the results, the Anisotropic IDW showed an acceptable performance, which is better than the traditional IDW and Indicator Kriging in both synthetic and real case studies (details in section 4). Finally, from the results of the conducted studies, it is apparent that Anisotropic IDW for veins modeling in anisotropic conditions is the most optimum method among considered.
Open Access
THE APPLICATION OF CAPACITANCE-RESISTANCE MODEL TO ANALYZE LOW SALINITY WATER FLOODING
(Nazarbayev University School of Mining and Geosciences, 2021-05-03) Ishanov, Akzhol
One of the most applied Chemical Enhanced Oil Recovery (CEOR) techniques is polymer flooding, which uses polymer solutions to increase the viscosity of the displacing water and enhance mobility control and sweep efficiency. Polymer flooding can be applied in mature oilfields, which already undergo secondary recovery with a gradual decrease in production. One such reservoir is the Uzen field, which is located in the western part of Kazakhstan. The Uzen field is one of the largest and oldest oilfields in the whole country and an increase in its oil production might be crucial to satisfy growing energy demand. ...
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, Moldir
A 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.
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APPLICATION OF FRACTAL ANALYSIS TO TRADITIONAL TOP-CUT IN RESOURCE ESTIMATION OF GOLD DEPOSITS
(Nazarbayev University School of Mining and Geosciences, 2022-04-11) Alimbay, Amirkhan
The accuracy of correct resource estimation is crucial in integrity of a feasibility study as well as the daily running of mining activities. The success of a mine operation depends on the correctness of resource estimation. In order to certify an acceptable level of confidence in resource modeling, it is necessary to construct a high-quality 3D block model, where in each block; the grade of interest is reported. However, each deposit has an exclusive structure and subsurface geology, thus, it is extremely complex to predict and produce such an exact model. In addition, the presence of extremely high values in the dataset negatively affects resource estimation and produces biased estimates. This problem is especially noticeable in gold deposits with a long-tailed distribution. There is a method in the industry to solve this problem so-called capping, where sample grades that exceed the provided specific threshold (cutting value) will be downgraded to a specific threshold. To reduce the impact of outliers to final resource estimation, a new Top-Cut technique was proposed. In this method, the grade variable is spitted into three parts: the truncated grade, an indicator and residual. The pros and cons of this method are that we can choose the value of the threshold manually. In practice, this value is selected by using various statistical techniques and sometimes it is quite objective. On one hand, this increases the variability of the method, but from the other hand, we do not have a specific rule for choosing the best and optimum threshold. Therefore, the use of fractal analysis can be useful, since the fractal model allows determining several populations in a dataset that can be used as individual thresholds. Moreover, to determine the best threshold, the ratio of indicator variogram analysis is used. This work utilizes a borehole dataset from a Kazakhstani gold deposit, where Traditional Top-Cut and Fractal Top-Cut modeling approaches are applied to model the Gold in this deposit. In order of comparison, conventional capping method is also applied. The results showed that Fractal Top-Cut outperforms the Traditional Top-Cut and capping technique in better resource modeling and produces more accurate results with better average grade above different cut-off grades and less mean error. However, the drawback is that the method does not produce a variance map.
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APPLICATION OF HYBRID ALUMINA/SILICA NANOFLUIDS FOR EOR IN CARBONATE RESERVOIRS
(Nazarbayev University School of Mining and Geosciences, 2022-05) Satay, Yernur
Nanoparticles are gaining their attraction in EOR(Enhanced Oil Recovery) with technology development and the slump in oil prices. Nanoparticles are particles whose size is between 1 and 100 nm. Adding nanoparticles into injection fluid during the EOR process may activate many mechanisms such as wettability alteration, IFT(interfacial tension) reduction, mobility control, log-jamming effect, change in the disjoining pressure, etc. The researchers believe that the wettability alteration is the most acceptable one among all these mechanisms. Nanoparticles have many unique characteristics, such as a high surface-volume ratio, significant possibility to modify their surface, suitability and stability in harsh reservoir conditions and being environmentally friendly. The oil recovery in carbonate reservoirs is less than 40%, mainly because of the wettability effect. Due to nanoparticles ' unique characteristics and active mechanisms in the EOR process, it is very promising to implement nanofluid flooding to produce more oil from carbonate reservoirs. Silica (SiO2) nanoparticles have been largely testified in improving oil recovery before. The effect of aluminum(Al2O3) nanoparticles on EOR is also being investigated recently. However, there is little research on the hybrid(Al2O3/SiO2) nanoparticles for EOR. The combination effect of silica nanoparticles and alumina nanoparticles on EOR will be studied in this research to compare the performance of the hybrid nanoparticles with silica nanoparticles. Firstly, zeta potential and zeta size measurements were conducted to test the stability of SiO2 nanofluid, Al2O3 nanofluid and the hybrid(Al2O3/SiO2) nanofluid. Then the contact angle was measured to analyze the nanofluid effect on rock/oil/brine systems to determine the optimum nanofluid concentration for further core flooding experiments and to testify to the wettability alteration mechanism in the EOR process. Finally, a core flooding experiment was conducted to study the performance of the optimal silica and hybrid nanofluid in enhancing oil recovery. The stability results showed that SiO2 nanofluid could stay stable for at least 3 days without adding a stabilizer while Al2O3 nanofluid cannot remain stable even for 10 minutes after homogenization. However, with the help of the stabilizer SDBS(sodium dodecylbenzenesulfonate), Al2O3 nanofluid can stay stable for 2 hours (the base fluid for dissolving nanoparticles is distilled water in all cases). From the results of contact angle measurements, considering the volume of nanoparticles used, we can get that the optimal SiO2 nanofluid's concentration is 0.1wt.%,the optimal Al2O3 nanofluid's concentration is 0.05wt.%, and the optimal hybrid nanofluid is 0.05wt.%Al2O3/0.1wt.%SiO2. The wettability alteration result indicated that none of these nanofluids altered oil-wet pellets to water-wet conditions. The optimal hybrid nanofluid works worse than the optimal SiO2 nanofluid on wettability alteration in carbonate reservoirs at 80℃ with 10 degrees difference. During the core flooding experiment, the injection rates were set at 0.5cc/m,2cc/m,5cc/m and 7 cc/m to simulate the real injection rate in the oilfield and counteract the capillary end effect. At 80℃, the CSW (Caspian Seawater) displaced 41.8% of the original oil in the core and the optimal silica nanofluid improved recovery to 45.9%, while the optimal hybrid nanofluid enhanced oil recovery to 73.1%.
Open Access
APPLICATION OF LOW SALINITY HOT WATER INJECTION IN CARBONATES
(Nazarbayev University School of Mining and Geosciences, 2022-04) Karabayanova, Leila
The high efficiency of Low Salinity Water (LSW) injection in carbonates, leading to rock wettability alteration from oil-wet to water-wet and, hence, resulting in better oil displacement, has been confirmed by numerous studies. In recent years, the combination of LSW injection with other Enhanced Oil Recovery (EOR) techniques has been widely discussed to activate the synergistic effects of hybrid EOR methods leading to additional oil recovery. The idea of combining LSW injection with a thermal approach, known as Low Salinity Hot Water (LSHW) injection, is a highly promising hybrid EOR method for heavy oil carbonate formations. In this study, the performance of LSW and hybrid LSHW injection was experimentally evaluated for heavy oil carbonate cores by different measurements of rock-fluid interactions and core flooding experiments. Contact angle measurements were conducted to investigate the optimal dilution of seawater (SW) and evaluate the performance of different variations of Potential Determining Ions (PDIs) concentration on wettability change. Appropriate dilution and ion management were applied to design LSW and engineered water (EW) for oil displacement at different temperatures (from 20°C to 70°C) in order to evaluate the standalone LSW and hybrid LSHW injection performance. The injection of LSW and EW was estimated to be inefficient for heavy oil carbonates, while hybrid LSHW flooding showed a significant increase of oil recovery with the best performance of the brine spiked by PDIs, where 60% and 55% of the residual oil was displaced at 50°C and 70°C, respectively. Moreover, the injection of LSHW directly after SW was found to be more practical than following LSW flooding. The application of the hybrid EOR method activates different mechanisms, such as oil detachment from the rock surface, due to the wettability alteration by EW/LSW and viscosity reduction by the thermal methods. Combined active mechanisms result in better performance, compared to the standalone EOR methods. Rock dissolution and multi-ion exchange by PDIs were identified as the main mechanisms of wettability alteration by EW/LSW via the results of ion chromatography analyses. The synergy between EOR methods affects the active mechanisms of LSW/EW flooding. For example, an increase in temperature showed more active multi-ion exchange and rock dissolution, which resulted in higher oil release from the rock surface.
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APPLICATION OF NATURAL POLYMER IN ENHANCED OIL RECOVERY
(Nazarbayev University School of Mining and Geosciences, 2024-04-15) Serikov, Galymzhan
With 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 flooding
Open Access
APPLICATION OF POLYMER FLOODING IN SANDSTONE RESERVOIRS OF UZEN FIELD
(Nazarbayev University School of Mining and Geosciences, 2021-07) Bekpayev, Ilyas
One of the most applied Chemical Enhanced Oil Recovery (CEOR) techniques is polymer flooding, which uses polymer solutions to increase the viscosity of the displacing water and enhance mobility control and sweep efficiency. Polymer flooding can be applied in mature oilfields, which already undergo secondary recovery with a gradual decrease in production. One such reservoir is the Uzen field, which is located in the western part of Kazakhstan. The Uzen field is one of the largest and oldest oilfields in the whole country and an increase in its oil production might be crucial to satisfy growing energy demand. A successful application of polymer flooding in a certain field requires a proper polymer selection followed by a well-planned and sophisticated assessment of its performance under reservoir conditions. This work is focused on the lab scale evaluation of three synthetic polymers performance in conditions of the Uzen field. The investigated polymers are co-polymers with functional groups of acrylamides (AM), Acrylamido-Tert-Butyl-Sulfonate (ATBS). Sav 10, Sav 19, and Sav 10 XV polymers. The work sequence: • Investigation of polymer concentration and temperate effects on rheological behavior of polymers • Mechanical stability under high shear rate • Evaluation of long-term thermal stability of polymers • Injectivity tests for the evaluation of permeability and mobility reduction due to polymers flooding at the core scale and required differential pressure for the injection. • Investigation of displacement efficiency of one the most suitable candidate at the core scale. Sav 10 polymer showed the best mechanical stability with the viscosity retention of 50 % after 10 minutes exposure to high shear rate. All candidates were able retain at least 50% of their initial viscosities after 2 months at 60 °C. The injection of Sav 10 polymer provided the best injectivity with the lowest differential pressures and permeability reduction. The application of Sav 10 flooding was effective and increased the cumulative oil recovery by 12 % after the brine flooding. To conclude, the polymer flooding with Sav 10 polymer in the conditions of the Uzen field was effective EOR technique and can be recommended for the implementation.
Open Access
APPLICATION OF SEQUENTIAL INDICATOR SIMULATION TO MODEL NON-STATIONARY GEOLOGICAL DOMAINS COMBINING WITH A MACHINE LEARNING ALGORITHM
(School of Mining and Geosciences, 2023-04-17) Amirzhan, Almas
Resource estimation is an essential aspect of the development process for any mining project. The geological domains are defined based on data obtained from boreholes, with the goal being to determine the mineral grades in the geological domains. Geostatistics assumes that the joint distribution of geological attribute values is consistent across homogeneous domains and is defined by a stationary covariance function. However, the nature of geological systems often contains uncertainties and variations in structure and behaviour. Sequential Gaussian and Sequential Indicator Simulation are one of several methods used for simulating continuous and categorical variables in 3D geological modelling. Despite its advantages, this method and other conventional techniques have been criticized for not effectively capturing local mean values, variance, and spatial continuity changes. The traditional algorithms used in the industry are not suitable for non-stationary geological domains, as they are designed for stationary target simulation variables. This thesis proposes using Multinomial Logistic Regression as an alternative method for simulating the spatial properties of non-stationary geological domains. The technique will be applied to a copper-porphyry deposit that shows clear signs of non-stationarity. The mineral resource model will be created by weighting the copper grade estimates based on the probability of occurrence of different rock types in various geo-domains. The generated probability maps will be evaluated using various criteria, including visual inspection of realizations, probability maps, replicas of each geo-domain fraction, connectedness metrics, and trend analysis.
Open Access
ASSESSING MINING PRODUCTIVITY IN KAZAKHSTAN: INDUSTRY AND FIRM-LEVEL ANALYSIS
(Nazarbayev University School of Mining and Geosciences, 2022-05) Azhibay, Seribolat
Productivity plays an essential role in the mining industry: its improvement is significant for domestic producers' long-term economic growth and competitiveness in the world market. Starting from the late nineteenth century, productivity has been increasing due to accessibility of high-grade ores, development in technology, innovations, improvement of the quality of healthcare, and workers’ education. However, in recent years, productivity has been decreasing worldwide. The main reasons cited for this decline are resource depletion, increasing costs for extracting lower quality and less accessible reserves, and reduced efficiency of existing, outdated technology and techniques. Understanding various factors affecting productivity can lead to better counteracting of these effects. Thus, mining productivity and factors that impact it need to be studied. This study investigates labor productivity in Kazakhstan’s mining industry from 2001 to 2020 with the main focus on energy consumption, expenditures on labor, capital, also on growth rates of production, employment, investment, and wages. In addition, it analyzes the relationship between productivity and key factors: capital per worker, energy intensity, recovery rate, head grade, waste ratio, and copper share, in the local firm KazMinerals. The results of statistical analysis for industry-level and regression analysis for the firm-level data indicate that regional industrial labor productivity has increased over the past twenty years by more than 5% on average. Furthermore, the research shows a high correlation between productivity and ore grade, recovery rate, energy consumption, and capital per worker.
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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, Mardan
Precipitation 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.
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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, Kemelkhan
In 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.
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Characterization of asphaltene from Kazakhstan crude oils
(Nazarbayev University School of Mining and Geosciences, 2020) Bakhytzhanova, Madina
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COMPARISON OF 124 MHZ AND 250 MHZ FREQUENCY GROUND PENETRATING RADAR FOR THE DETECTION OF BURIED PIPES
(School of Mining and Geosciences, 2023-04-20) Ismagulov, Shyngys
The petroleum industry plays a crucial role in the global economy, but the construction and operation of underground pipelines in petroleum fields are associated with significant economic and environmental challenges. This thesis aims to evaluate the efficiency of ground-penetrating radar (GPR) and compare the effectiveness of Cobra Plug-In GPR (124 MHz) and LMX200 GPR (250 MHz) for detecting buried pipes. The study also addresses the problems of identifying buried pipes, including their depth, type, and location. A comprehensive literature review was conducted, and an experimental methodology was proposed. Measurements were taken in three different areas using both GPR systems in the summer and winter, and appropriate data processing and interpretation were presented. Area 1, located at coordinates 51°5’25.58"N, 71°23’14.64"E, contains objects that are buried between depths of 1.8 to 4 meters. In Area 2, situated at coordinates 51°5’20.98"N, 71°23’25.20"E, an empty pipe is buried at a depth of 3 meters in the trench. Area 3, located at coordinates 51° 5'28.11"N, 71°23'33.23"E, has underground utilities that are buried at a depth of 2.2 meters. The study demonstrated the effectiveness of GPR in detecting buried objects and highlighted the importance of the direction of the field survey and the use of different GPR systems. Comparing results obtained using different GPRs showed that 124 MHz and 250 MHz GPRs effectively detect underground pipelines, even in challenging conditions such as frozen soil. The results show that GPR systems are influenced by the geometry of the field survey direction and the impact of surface objects on the GPR image. The present study can inform future research and practices in the field of petroleum engineering, with potential applications for improving pipeline safety, reducing costs, and minimising environmental impact.
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COMPARISON OF 124 MHZ AND 250 MHZ FREQUENCY GROUND PENETRATING RADAR FOR THE DETECTION OF BURIED PIPES
(School of Mining and Geosciences, 2023-04-20) Ismagulov, Shyngys
The petroleum industry plays a crucial role in the global economy, but the construction and operation of underground pipelines in petroleum fields are associated with significant economic and environmental challenges. This thesis aims to evaluate the efficiency of ground-penetrating radar (GPR) and compare the effectiveness of Cobra Plug-In GPR (124 MHz) and LMX200 GPR (250 MHz) for detecting buried pipes. The study also addresses the problems of identifying buried pipes, including their depth, type, and location. A comprehensive literature review was conducted, and an experimental methodology was proposed. Measurements were taken in three different areas using both GPR systems in the summer and winter, and appropriate data processing and interpretation were presented. Area 1, located at coordinates 51°5’25.58"N, 71°23’14.64"E, contains objects that are buried between depths of 1.8 to 4 meters. In Area 2, situated at coordinates 51°5’20.98"N, 71°23’25.20"E, an empty pipe is buried at a depth of 3 meters in the trench. Area 3, located at coordinates 51° 5'28.11"N, 71°23'33.23"E, has underground utilities that are buried at a depth of 2.2 meters. The study demonstrated the effectiveness of GPR in detecting buried objects and highlighted the importance of the direction of the field survey and the use of different GPR systems. Comparing results obtained using different GPRs showed that 124 MHz and 250 MHz GPRs effectively detect underground pipelines, even in challenging conditions such as frozen soil. The results show that GPR systems are influenced by the geometry of the field survey direction and the impact of surface objects on the GPR image. The present study can inform future research and practices in the field of petroleum engineering, with potential applications for improving pipeline safety, reducing costs, and minimising environmental impact.
Open Access
COMPARISON OF CAPACITANCE-RESISTANCE MODEL AND TRACER FLOODING TO ESTIMATE INTERWELL CONNECTIVITY
(Nazarbayev University School of Mining and Geosciences, 2022-05) Aliyev, Adilet
When it comes to managing waterflooding activities in a field, interwell connection is a critical factor to consider. This parameter is important to be analyzed to determine the distribution of injected fluids in a reservoir and toward the producing wells. The Capacitance-Resistance Model (CRM), which was first developed in the early 2000s, is an analytical technique for waterflooding modeling and optimization. Producing and injecting data are utilized as input in order to calculate the material balance and estimate factors such as the interwell connectivity of the wells. This study was focused on the accuracy of applying the Capacitance-Resistance Model to estimate the interwell connectivity and compare it with results obtained by tracer flooding tests. A technique like this allows for a more accurate assessment of the link between the wells as well as a more cost-effective and timely choice on the next field development stages. Data from tracer tests and CRM were used to determine connectivity values for synthetic and actual fields, which were then examined and compared. CRM was capable of modeling floods and estimating production in these areas with a level of accuracy that was acceptable. In order to increase the accuracy of the CRM technique used to compute the interwell connection between injector/producer pairs, other parameters such as well spacing and fluid loss during the injection were taken into consideration. CRM, according to our findings, may be used to provide a rapid approximation of interwell connection under specific assumptions, and it is suggested as a substitute for tracer flooding analysis in situations when the tracer test is either not feasible or too costly to do.
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COMPOSITIONAL SIMULATION OF SOUR GAS RE-INJECTION INTO CARBONATE RESERVOIRS
(Nazarbayev University School of Mining and Geosciences, 2022-05) Suleimen, Mukhabbat
One of the major obstacles considering ecology is sour gas, which accompanies natural gas in almost half of all producing reserves in the world. The major oilfields in North Caspian Sea Region all produce high concentration of sour gas. However, only during the last decades has sour gas been used for enhanced oil recovery (EOR) for twin advantages, both economically and environmentally. Sour oil and gas, with high acidic gas content such as hydrogen sulfide and carbon dioxide, have high toxicity and cause corrosion of equipment. Overcoming most of these challenges in carbonate reservoirs with high H2S content would facilitate oilfields to keep the supply high enough to meet the high oil and gas demand. This work first conducted a literature review about the application of H2S flooding in oil reservoirs. Then CMG compositional simulator was used to investigate the feasibility of sour gas injection into carbonate reservoir for EOR. Injection of CH4/H2S and CO2/H2S gas mixtures into reservoir sector models were simulated for assessing oil recovery potential. The results of modeling four different reservoir models, including 2D homogeneous, 2D heterogeneous, 3D homogeneous, and 3D heterogeneous models, showed high concentration sour gas injection is superior as compared to low concentration gas mixtures. Sour gas injection with high H2S content achieved higher oil production rate than other low content cases, this can be attributed to the increase in displacing fluid viscosities toward lower mobility ratios during the injection and easier miscibility of H2S with crude oil.
Open Access
CORRELATION BETWEEN SLAKE DURABILITY INDICES AND STRENGTH OF COAL FROM KARAGANDA COAL BASIN
(Nazarbayev University School of Mining and Geosciences, 2022-08-08) Bekmurat, Altynay
The uniaxial compressive strength is a very important parameter in mine design. For weak rocks such as coal, it is particularly difficult to obtain cores for mechanical testing. Especially for the weak rocks, another possibility of obtaining strength can be slake durability test (SDT) that is quick and inexpensive. A laboratory testing project was designed and carried out to characterize some physical (porosity and bulk density) and mechanical properties (UCS and PLI) and also slake durability indices (SDI)....
Open Access
DATA-DRIVEN ANALYSES OF LOW SALINITY WATERFLOODING IN CARBONATES
(Nazarbayev University School of Mining and Geosciences, 2021-07) Salimova, Rashida
Maximizing crude oil recovery is a main objective of the oil and gas industry. Oil recovery by natural production in carbonates is usually lower than 30%. Thus, Enhanced Oil Recovery (EOR) methods are used to increase the oil production in carbonate reservoirs. Low salinity water (LSW) injection is a promising EOR technique, which have been studied by many researchers for potential improvement of oil recovery. LSW flooding in carbonates has been widely evaluated by coreflooding tests in prior studies. A closer look in the literature on LSW in carbonates indicates a number of gaps and shortcomings. It is difficult to understand the exact relationship between different controlling parameters and the LSW effect in carbonates. The active mechanisms involved in oil recovery improvement are still uncertain, and more analyses are required. To predict the LSW performance and study the mechanisms of oil displacement, data collected from available experimental studies on LSW injection in carbonates were analyzed using data analysis approaches. In this thesis, I collected data from 26 secondary and 117 tertiary coreflooding tests. Machine learning (ML) and statistical approaches were utilized to analyze the extracted main parameters. We used a linear regression model to study the linear relationship between single parameters and incremental recovery factor (RF). Correlations between rock, oil, brine properties and tertiary RF were negligible and weak. Subsequently, we analyzed the effect of brine and oil/brine parameters (oil acidity, alteration in salinity and active ions concentration) on LSW performance using multivariable linear regression. Relatively stronger linear correlation was found for a combination of oil/brine parameters and RF. We also studied the nonlinear relationship between parameters by applying ML nonlinear models, such as Artificial Neural Networks (ANN), Support Vector Machine (SVM) and Decision Tree (DT). These models showed better data fitting results compared to linear regression. Strong and very strong relationships between properties and RF were achieved by ML models. Among the used ML models, DT provided the best correlation for oil/brine parameters, as ANN and SVM overfitted the testing data. Finally, different mechanisms involved in the LSW effect were analyzed based on the changes in the effluent PDIs concentration, interfacial tension, pH, zeta potential, pressure drop. Wettability alteration by LSW was commonly observed in coreflooding tests.