VNUHCM Journal of Engineering and Technology

Latest Articles

1. Research article

   Preparation of nanocarbon and metal oxide based composite material for X-band electromagnetic absorption

   Ha B., Nguyen T., Nguyen C., Hoanh T., Hoa N., Ngo H., Le H., Tri L.

   Electromagnetic waves are believed to be highly effectively absorbed by composite materials based on nanocarbon and magnetic oxides. In this study, NiFeMgOx multi-metal oxide nanoparticles were prepared by homogeneous precipitation process and then, CNT fibers were chemically vapor deposited onto NiFeMgOx to obtain the CNT/NiFeMgOx material. SEM, XRD, and BET techniques were used to characterize the composition of composite materials, and electromagnetic properties such as conductivity, coercivity, and saturation magnetic moment were also investigated. The findings of the study indicated that CNT fibers grew effectively on the surface of NiFeMgOx nanoparticles. Multi-metallic oxide composed of NiO, FeO and MgO covered with highly graphitized CNTs fibers. The resulting composite material exhibited a concentrated pore distribution ranging from 10 to 50 nanometers and a specific surface area of 90 m2/g. The micro-structured material includes hollow carbon nanotube (CNT) fibers measuring approximately 50 nm in diameter and 2 nm to 4 nm in wall thickness. The CNTs/NiFeMgOx material showed low coercivity (Hc = 1500 Oe) and high magnetic saturation (Ms = 11.5 emu/g), which makes it a great candidate for the fabrication of materials that absorb electromagnetic radiation. On the basis of CNT/NiFeMgOx composites, magnetic powder, carbon black, and adhesives, electromagnetic wave-absorbing materials are produced. The results suggest that an X-band material with a thickness of 1.5 mm and an adhesive content of 20% may successfully reduce electromagnetic wave reflection by up to to be -35 dB. The CNTs/NiFeMgOx composite material has a lot of opportunities to develop to a novel electromagnetic wave adsorbent material system with numerous outstanding characteristics.

   Published: 2024-03-18In press
2. Research article

   Enhanced efficiency MnO2-Promoted pt catalyst for VOCs oxidation

   Manh Hung K., Hien T., Bang H.

   One of the leading causes of air pollution, volatile organic compounds (VOCs) pose a severe danger to both the environment and human health. In heat or light, catalytic oxidation has been recognized as a promising and successful approach for treating VOCs. Due to their affordability and environmental friendliness, manganese-based oxides are one of the most competitive and acceptable choices for the catalytic destruction of VOCs. In this study, we disperse Pt on MnO2 with trace Pt loadings of 0.5, 1, and 1.5 wt% to control the interaction of Pt-MnO2 (MnO2 = manganese oxide). In comparison to MnO2, the Pt-MnO2 catalyst exhibits higher VOCs oxidation performance due to its higher Brunauer-Emmett-Teller surface area, more active lattice oxygen, increased oxygen vacancy activating increased dioxygen molecules, more exposed Pt atoms, and noninternal diffusion of mass transfer. Among all the plantinum samples created with varying mass ratios, the Pt-MnO2 sample demonstrates the best characteristic characteristics as well as catalytic activity. The specific surface area of Pt-MnO2 is 108.74 m2/g. The Pt-MnO2 catalyst can totally convert Toluene into CO2 and H2O at a lower temperature of just 190 C while maintaining great stability for 600 minutes. Under conditions of high space velocity, the Pt-MnO2 catalysts' performance in oxidizing VOCs is steady, indicating tremendous promise for real-world use. This research shows that a Pt-dispersed MnO2 catalyst is superior to a MnO2 catalyst for the oxidation of VOCs, offering universally significant advice for the interaction of metals with supports and the control of interfaces during oxidation processes. The results suggest that the synthesized Pt-MnO2 material has a comparatively strong capacity to oxidize VOCs at low temperatures and a high stability, and that it can be developed and scaled up to a wider application scale.

   Published: 2024-03-18In press
3. Research article

   Proposing solutions to calculate water level lowering for underground works in different hydrogeological conditions

   Hải Đào Sơn N.ễn

   Currently, during the construction of high-rise buildings with basements, or underground works below ground level in our country, phenomena such as the bottom of the foundation pit, sand flowing on the side of the diaphragm wall, and ground subsidence occur, ... causing serious damage to people and property. These phenomena often occur during the pumping process to lower the groundwater level. One of the reasons leading to the above phenomena is that the assessment of hydrogeological characteristics of the construction area is unclear, so design calculation methods are applied that are not suitable for each application condition. In addition, during the operation of the drainage systems to lower the underground water level, it has not been strictly controlled, so when the water level is lowered too much (exceeding the allowable limit), the construction unit has no remedial measures. appropriate and timely. In this article, the authors provide formulas to calculate the flow corresponding to the water level lowered according to design applicable to complete and incomplete well conditions, applied in hydrogeological conditions. different literature. In addition, the authors provide steps to calculate pump flow when designing and propose a flowchart to control the design and operation of the drainage system to lower the groundwater level with the hope of helping implementation units. The company has a more general view of the process of calculating and designing the dry drain system, thereby being able to operate the system more safely.

   Published: 2024-03-12In press
4. Research article

   Applying interpreted results of drill stem test to assess reservoir characterization at well KB-3X, Kinh Bac oilfield, block 09-2/09

   Tuấn N.,ễn Xuân T.,ần Khá N.,ễn Hương T.,ần Trang N.,ễn Ly N.ễn

   With the current energy transition trend of the oil and gas industry, in order to increase efficiency, optimize exploitation and save resources, formation evaluation is necessary to best exploit a reservoir. The objective of this study is to evaluate the formation quality of the E sequence, X oilfield, block 09-2/09 in the Cuu Long basin. The research is based on the properties and flow capacity of the reservoir, using well parameters of pressure, volume, temperature and petrophysical data of well KB-3X. This study was conducted using two interpretive methods are traditional and advanced methods. The traditional interpretation method will establish a graph between Horner time and well bottomhole pressure pws and then apply calculation formulas to determine the parameters of the reservoir. The advanced interpretation method uses Ecrin software to interpret reservoir test results. Both methods give negative Skin coefficients, proving effective well completion. The results of reservoir parameters obtained from the advanced method are determined in accordance with geological documents as follows: the initial pressure of the reservoir is pi= 5564,79 psi, permeability K=3,59 mD, hydro conductivity equals kh=306 mD.ft=93 mD, coefficient Skin S=-2,69, well storage coefficient evaluates to C=0,0024 bbl/psi, productivity index PI=0,56 bbl/d/psi and distance to fault L=2250ft = 686m. The interpretation process with the help of Ecrin software has allowed to overcome the limitations in traditional methods when applying many well, reservoir and boundary models. The results after this process show that the reservoir quality of the E sequence is still limited, and the ability to produce commercial flows is poor when the permeability value is low (K=3,59mD). The significance of the research results is to supplement input data for simulation models and field development planning, thereby providing the most appropriate exploitation plan and economic plan for the oil industry to achieve commercial efficiency better.

   Published: 2024-03-12In press
5. Research article

   Selecting an Appropriate Rheological Model for Environmentally Friendly Water-Based Drilling Fluid

   Le N., Hau D., Phat L., Hieu L., Phuoc T., Dung T., Quang H., Tam T.

   A vital component of oil and gas drilling operations is drilling fluid. Water-based drilling fluids have been enhanced with organic-based components to encourage the protection of the environment and sustainable development. Recently, materials derived from orange peels have been studied and found useful in improving the quality of water-based drilling fluids. This study examined mathematical models to describe the rheological properties of water based drilling fluids incorporating orange peel powder in various concentration. Selecting a suitable rheological model facilitates the estimation of pressure losses and enables more precise hydraulic calculations. Three rheological models, namely Bingham Plastic, Power Law and Herschel-Bulkley, were investigated. To assess the accuracy of the models compared to experimental data obtained in the laboratory, performance metrics including Mean Absolute Percentage Error (MAPE), Mean Squared Error (MSE), and Coefficient of Determination (R2) were employed. The results indicate that the rheological behavior of drilling fluids incorporating orange peel powder can be adequately represented by the Herschel-Bulkley model, exhibiting the highest R2 value, lowest MAPE and MSE values when compared to the Power Law model and Bingham Plastic model.

   Published: 2024-03-11In press
6. Research article

   Research of the characteristics and technical requirements on brick products using fly ash and slag ash

   Nguyen S., Huynh H., Nguyen H.

   Currently, along with socio - economic development, the demand for construction materials is increasing, and there is a need to promote the use of environmentally friendly materials. On the other hand, the amount of fly ash and slag from coal - fired thermal power plants increases rapidly each year and the dumps are almost overloaded, so the urgent problem is solutions research to increase consumption of fly ash and slag. Therefore, the research about testing and putting into use of unfired bricks with main components of fly ash and slag can be considered a comprehensive solution, both without causing harm to the environment, without wasting natural materials, and consuming large amounts of fly ash and slag. In this study, the experimental brick mixes were designed using ash and slag to replace part or all of the crushed stone, and the cement was replaced by fly ash in different proportions, of which, the total amount of fly ash and lag used is more than 80% of the total amount of raw materials. The test results show that the characteristics of bricks such as compressive strength, flexural strength, bulk density,... are still satisfactory compared to conventional concrete bricks and traditional clay bricks, and even have more advantages. However, using the standards of concrete bricks or clay bricks to evaluate unfired bricks produced from fly ash and slag, the results are only approximate, because the material composition and production process are different. Therefore, this paper proposes specific technical requirements for unfired bricks produced from fly ash and slag.

   Published: 2024-03-11In press
7. Research article

   Modeling of 2-phase flow in porous media using physics-informed neural network

   Phạm T.,ìn., Mai Lân

   Oil and gas are valuable resources and make a great contribution to the national economy. However, this resource is often located thousands of meters underground. Therefore, oil and gas production and exploitation conditions cannot be measured directly but must be through simulations. Specifically, the models here simulate the behavior of fluids in oil and gas reservoirs to predict and optimize oil and gas exploitation. Besides traditional numerical simulation models, artificial neural networks are a good alternative. This study investigates and presents the advantages as well as disadvantages of the physics-informed neural network (PINNs) approach in the modeling of a simple oil production process by water flooding method with the Buckley-Leverett theory. The results from PINNs in this study agree quite well with the analytical solutions of the differential equation to be solved. The results from this work also show that PINNs can be applied to problems in which the unknowns have stiff changes with respect to space/time and that PINNs are absolutely suitable for problems where data availability is limited such as those for oilfield development/production planning. Furthermore, PINNs trained models are reliable and able to be utilized for long term production forecasts thanks to the consideration of physics information during the training of the network. This shows that PINNs would be highly applicable in the modeling of two-phase flows in porous media.

   Published: 2024-03-11In press
8. Research article

   History matching for the X−1P well taking into account the characteristics of gas condensate flow in the near-wellbore region

   Nguyễn T.,ườn., Cao Lân

   This paper presents an improvement in the history matching results of a gas condensate well operating under dew point pressure conditions with significant condensate dropout phenomena. This phenomenon poses challenges for history matching efforts and reliable production forecasting, especially in the context of most gas condensate fields being produced in the pressure depletion stage nowadays. In this study, particular attention is given to the characteristics of the gas condensate flow that describe the condensate dropout phenomenon in the near-wellbore region, thereby enhancing the history matching. The key characteristics of gas condensate flows include Generalized Pseudo-Pressure (GPP), Velocity Dependent Relative Permeability (VDRP), and non−Darcy flow. These three characteristics are of particular importance in the near-wellbore region, and each of them is described in detail to capture the physical behavior of the complex gas condensate flow. The actual production data, such as production rate and bottom-hole pressure, are used as the targets to elucidate the significant impact of considering these three characteristics on the history matching. This work demonstrates the necessity of considering these characteristics to describe the behavior of gas condensate flow, and ultimately shows improved history matching results compared to the conventional approach.

   Published: 2024-03-11In press
9. Research article

   2D and 3D numerical investigation on geosynthetic-Reinforced piled-Embankment over soft ground

   Pham T., Liem N.

   The geosynthetic reinforcement solution, whether in the form of geogrids or geotextile reinforcement, combined with a group of reinforced piles in an embankment on soft ground, proves to be a rapid and effective approach for projects situated on granular embankments. However, the complexity of working mechanisms is a challenge for engineers as it can impact the performance of solution under different real-world conditions. Indeed, load transfer is a complex mechanism conditional upon the interaction among connecting elements, such as piles, soil, and geosynthetics. In this study, a numerical model was constructed using the finite element method, incorporating both 2D and 3D models to simulate an experiment conducted by Liu et al. This paper described a case history of a geogrid-reinforced and pile-supported highway embankment with a low area improvement ratio. The present study focused on evaluating surface settlement, stress distribution on soft ground, and the effectiveness of load transfer within a reinforced embankment through a system of interconnected piles with geosynthetics and subsoil. The results of the study indicated that both 2D and 3D models accurately reflected the behavior of the piles, but there were differences in simulating stress on soft ground and load transfer within the embankment. The 2D model proved more suitable for simulating stress on the soft ground surface, while the 3D model achieved a high level of accuracy (1% deviation from observational results) in simulating the load transfer within the embankment. These findings highlight the complex nature of load transfer mechanisms and highlight the importance of considering both 2D and 3D modeling approaches when assessing the performance of a geogrid-reinforced and pile-supported highway embankment over soft clay under various conditions.

   Published: 2024-03-11In press
10. Research article

    Evaluating of formation quality by interating core data and well log data in E sequence, X oilfield, Cuu Long Basin

    Tuấn N.,ễn Xuân T.,ần Thanh T.,ươn., Hương T.,ần Huy N.,ễn Huy P.ạm

    The X oilfield has a total of 4 wells, namely 1X, 2X, 3X and 4X. Sediment E sequence of X oilfield is the object of research in this study and has been determined to consist of 3 main distribution (E3, E4 and E5) and the distribution E clay above. Well logging measurements were performed throughout the E sequence for all 4 wells, core samples were taken at distribution E4 (at well 2X and 3X) and E5 (at well 4X). From the research results, it is shown that the formation of E sequence set has poor to moderate quality, but there are locations with good porosity and permeability. The low clay content in the reservoir (the average value of core samples for wells 2X, 3X and 4X is 6.96%, 8.94% and 5.7%, respectively, is a favorable factor for flow in the reservoir. The porosity-permeability relationship has a high correlation coefficient, so it is possible to trust this relationship to calculate the permeability for locations where the permeability measurement from the core sample is not performed. In order to evaluate the formation quality E of X oilfield accurately and comprehensively in all aspects, it is necessary not only to rely on core analysis and well-logging data, but also needs to be combined with conducting DST (Drill Stem Test), as well as other geological and stratigraphic methods.The results of the determination of porosity and permeability are not the same in 4 wells, showing the complicated change of facies of E sequence in the structure of X oilfield, so when simulation a wells, it is necessary to be careful and consider carefully based on building a map of the distribution of facies, in order to contribute to improving the efficiency of the oil and gas search and exploration process, reduce geological and economic risk factors, and provide more information to evaluate accurately and efficiently price oil and gas reserves.

    Published: 2024-03-11In press