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    Investigating the role of ultrasonic wave on two-phase relative permeability in a free gravity drainage process

    , Article Scientia Iranica ; Vol. 21, issue. 3 , 2014 , p. 763-771 Keshavarzi, B ; Karimi, R ; Najafi, I ; Ghazanfari, M. H ; Ghotbi, C ; Sharif University of Technology
    In this work, the process of free gravity drainage under the influence of ultrasonic waves was investigated. A glass bead pack porous medium was used to perform free fall gravity drainage experiments. The tests were performed in the presence and absence of ultrasonic waves, and the data of recovery were recorded versus time under both conditions. The wetting phase relative permeability curves were obtained using the data of recovery versus time, based on the Hagoort backward methodology. Subsequently, using the wetting phase relative permeability curve, the relative permeability of non-wetting phases were calculated by performing history matching to the experimental production data. The... 

    An Investigation on the Influence of EAF Slag Particle Size on AMD Neutralization Behavior in Static and Dynamic Slag Leaching Systems

    , Article Mine Water and the Environment ; Volume 34, Issue 2 , 2015 , Pages 204-212 ; 10259112 (ISSN) Alizadeh, A ; Shoushtari Zadeh Naseri, P ; Sharif University of Technology
    Springer Verlag  2015
    Steel slag, which contains basic oxides capable of generating high levels of alkalinity, may be used in leaching beds or leaching channels to neutralize acid mine drainage (AMD). In the present study, electric arc furnace (EAF) slag from the Pasargad Steel Complex was used to investigate the influence of slag particle size on AMD treatment. Three slag samples with different particle size distributions (coarse, mixed, fine) were prepared. Slag composition, pH variation, level of alkalinity, and specific surface area were measured and the surfaces of the slag particles was examined by scanning electron microscopy. In both dynamic and static leaching tests, there proved to be three stages: an... 

    Numerical study of the effects of drainage systems on saturated/unsaturated seepage and stability of tailings dams

    , Article Mine Water and the Environment ; Volume 36, Issue 3 , 2017 , Pages 341-355 ; 10259112 (ISSN) Pak, A ; Nabipour, M ; Sharif University of Technology
    The stability of tailings dams is affected by seepage characteristics such as the location of the phreatic surface inside the dam, the effects of the capillary fringe, and the unsaturated zone above the zero pore pressure level. In this study, the performance of drainage systems in tailings dams was investigated by analyzing saturated and unsaturated seepage in the dam, considering the effects of the construction method, tailings properties, and the type of drainage systems. First, general seepage characteristics in tailings dams were studied and the effects of non-homogeneity were investigated. Our results show that in a silty tailings dam with a height of 15 m, unsaturated plus capillary... 

    Analytical modeling of oil production from a matrix block by free fall gravity drainage mechanism

    , Article Energy Exploration and Exploitation ; Volume 31, Issue 6 , October , 2013 , Pages 821-832 ; 01445987 (ISSN) Ghorbanizadeh, S ; Ardakany, M ; Ghazanfari, M ; Sharif University of Technology
    Free fall gravity drainage is the most effective mechanism in gas invaded zone of fractured reservoirs. Although several analytical models have been proposed to characterize this mechanism, most of them suffer from inadequate reality, such as neglecting capillary pressure. In this study, a new analytical model was proposed to predict the oil recovery versus time for a homogeneous matrix block under a free fall gravity drainage mechanism. Considering the effect of viscous, gravity as well as capillary forces, the model was developed. This model is applicable to different conditions of gravity and capillary force, as well as when both forces are active. Along with core scale experimental data... 

    An improvement of the matrix-fracture transfer function in free fall gravity drainage

    , Article Petroleum Science and Technology ; Vol. 31, issue. 24 , Apr , 2011 , Pages. 2612-2620 ; 10916466 (ISSN) Samimi, S. E ; Masihi, M ; Sharif University of Technology
    The simulation of fractured reservoir is conventionally performed by using dual porosity formulation in which the type of transfer function may be critical. Over the past few years, various models with their strength and weakness have been developed to account for matrix-fracture interporosity flow. However, some of them are unable to simulate some mechanisms like gravity drainage. In this work, the most well-known transfer functions have been examined for simulation of the gravity drainage in a single block model and an improvement has been introduced to modify them. The validation of the developed approach have been done by using fine grid simulation  

    Experimental Study of Geotextile's Drainage and Filtration Properties in Dams under Different Hydraulic Gradients and Boundary Conditions

    , M.Sc. Thesis Sharif University of Technology Zahmatkesh, Zahra (Author) ; Pak, Ali (Supervisor)
    Geotextiles are one of the most widely used materials in filtration and drainage applications. Since geotextiles are exposed to different stresses and hydraulic gradients, thier hydraulic behavior in real situations is of great importance. In this study, filtration and drainage of several nonwoven needle-punched geotextiles with different properties and unit masses per area of 200g/m2, 400g/m2, 500g/m2 and 800g/m2 under various confined stresses and hydraulic gradients are investigated. To get to these aims, permittivity and transmissivity apparatuses were designed and built in the course of this investigation. Then samples which were emerged for at least 24 hours were tested under different... 

    Design of Pavement Subdrainage for Iran

    , M.Sc. Thesis Sharif University of Technology Pouranian, Mohammad Reza (Author) ; Tabatabaei, Nader (Supervisor)
    It is widely recognized today that excess moisture in pavement layers, when combined with heavy truck traffic and moisture-susceptible materials, can reduce the service life. Temperatures below freezing can also contribute to durability problems of saturated materials. A major objective in pavement design is to keep the base, subbase, subgrade, and other susceptible paving materials from becoming saturated or even being exposed to constant high moisture levels over time. The use of subsurface drainage has gained popularity over the past two decades, and many pavement agencies now routinely specify drainable pavement structures to reduce moisture-related problems in avements. In this... 

    Factors affecting the gravity drainage mechanism from a single matrix block in naturally fractured reservoirs

    , Article Special Topics and Reviews in Porous Media ; Volume 2, Issue 2 , 2011 , Pages 115-124 ; 21514798 (ISSN) Dejam, M ; Ghazanfari, M. H ; Mashayekhizadeh, V ; Kamyab, M ; Sharif University of Technology
    Despite numerous experimental and numerical studies, fundamental understanding of how the matrix block height, the density difference between petroleum and gas, and matrix capillary pressure could affect the oil recovery from a single matrix block in naturally fractured reservoirs remains a topic of debate in the literature. In this work a one-dimensional gravity drainage model developed by Firoozabadi and Ishimoto (1994) is considered and numerically solved. The Fourier series method is applied for a numerical Laplace inversion of the dimensionless mathematical model; this type of inversion method has rarely been used in petroleum applications. The obtained results revealed that by... 

    Neural Network Meta-Modeling of Steam Assisted Gravity Drainage Oil recovery processes

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 29, Issue 3 , Summer , 2010 , Pages 109-122 ; 10219986 (ISSN) Najeh, A ; Pishvaie, M. R ; Vahid, T ; Sharif University of Technology
    Production of highly viscous tar sand bitumen using Steam Assisted Gravity Drainage (SAGD) with a pair of horizontal wells has advantages over conventional steam flooding. This paper explores the use of Artificial Neural Networks (ANNs) as an alternative to the traditional SAGD simulation approach. Feed forward, multi-layered neural network meta-models are trained through the Back-Error-Propagation (BEP) learning algorithm to provide a versatile SAGD forecasting and analysis framework. The constructed neural network architectures are capable of estimating the recovery factors of the SAGD production as an enhanced oil recovery method satisfactorily. Rigorous studies regarding the hybrid... 

    Simulation of multiphase flows in porous media with gravitational effects using dominant wave method

    , Article International Journal of Numerical Methods for Heat and Fluid Flow ; Volume 23, Issue 7 , 2013 , Pages 1204-1224 ; 09615539 (ISSN) Moshiri, M ; Manzari, M. T ; Hannani, S. K ; Rasouli, A ; Sharif University of Technology
    Purpose - In this paper, the flow of multiphase fluids in a one-dimensional homogeneous porous media involving the gravity effects is numerically studied using the dominant wave method. The paper aims to discuss these issues. Design/methodology/approach - The numerical scheme used for solving the pressure equations, obtained for the black-oil model, is a backward Euler scheme while the hyperbolic mass conservation equations, derived for both black-oil and Buckley-Leverett models, are solved using the dominant wave method. Higher-order schemes are achieved using either variable derivatives along with the minmod limiter or a MUSCL type interface construction scheme using the Fromm's limiter.... 

    The effect of geometrical properties of reservoir shale barriers on the performance of Steam-assisted Gravity Drainage (SAGD)

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 34, Issue 23 , 2012 , Pages 2178-2191 ; 15567036 (ISSN) Fatemi, S. M ; Sharif University of Technology
    Many bitumen reservoirs contain shale layers of varying thickness, lateral extent, and frequency. These shale layers, depending on their size, vertical and horizontal locations, and continuity throughout the reservoir, may act as a flow barrier and severely reduce vertical permeability of the pay zone and slow down the steam-assisted gravity drainage steam chamber development. Therefore, to improve productivity in these reservoirs, understanding of the effects of reservoir heterogeneities has become necessary. This work presents numerical investigation of the effects of shale barriers on steam-assisted gravity drainage performance when applied to produce mobile heavy oil. The most concern of... 

    An experimental investigation of fracture tilt angle effects on frequency and stability of liquid bridges in fractured porous media

    , Article Petroleum Science and Technology ; Volume 30, Issue 8 , Mar , 2012 , Pages 807-816 ; 10916466 (ISSN) Mashayekhizadeh, V ; Kharrat, R ; Ghazanfari, M. H ; Dejam, M ; Sharif University of Technology
    Liquid bridges are believed to play an important role in improving the recovery of fractured reservoirs. However, little is known about the stability of liquid bridges in fractured media at the pore scale. In this work, a glass micromodel representing a stack of two blocks was used at different tilt angles to monitor the frequency and stability of liquid bridges formed during free-fall gravity drainage as a function of tilt angle. It was observed that by increasing the tilt angle, the liquid bridge frequency decreased but its stability increased. This resulted in higher ultimate recovery. In addition, it was found that during the first half of the experiments, the number of bridges was... 

    Pore-Level Observation of Free Gravity Drainage of Oil in Fractured Porous Media

    , Article Transport in Porous Media ; Volume 87, Issue 2 , 2011 , Pages 561-584 ; 01693913 (ISSN) Mashayekhizadeh, V ; Ghazanfari, M. H ; Kharrat, R ; Dejam, M ; Sharif University of Technology
    This work presents results from two sets of experiments conducted to study, in pore level, the role of fracture aperture and tilt angle on the stability of liquid bridges and the shape of a front during free gravity drainage process. Glass micromodels of two different aperture sizes were used to monitor the mechanism of gravity drainage of air-crude oil system, rotating around a bottom corner to create different tilting angles. Oil content within the matrix blocks was determined as a function of time using a series of images obtained during the experiments, from which net drainage rate from the upper and lower matrix blocks is calculated. Liquid bridges are more frequent but less stable at... 

    Free fall and controlled gravity drainage processes in fractured porous media: Laboratory and modelling investigation

    , Article Canadian Journal of Chemical Engineering ; Volume 93, Issue 12 , October , 2015 , Pages 2286-2297 ; 00084034 (ISSN) Saedi, B ; Ayatollahi, S ; Masihi, M ; Sharif University of Technology
    Wiley-Liss Inc  2015
    Gravity drainage is known to be one of the most effective methods for oil recovery in fractured reservoirs. In this study, both free fall and controlled gravity drainage processes were studied using a transparent fractured experimental model, followed by modelling using commercial CFD software. The governing equations were employed based on the Darcy and mass conservation laws and partial pressure formulation. Comprehensive examination was done on variables such as fluid saturation, velocity, and pressure distribution in the matrix and fracture, as well as fluid front level and production rate. Additionally, effects of the model parameters on the gravity drainage performance were... 

    Experimental and modelling study of gravity drainage in a three-block system

    , Article Transport in Porous Media ; 2020 Erfani, H ; Karimi Malekabadi, A ; Ghazanfari, M. H ; Rostami, B ; Sharif University of Technology
    Springer Science and Business Media B.V  2020
    Gravity drainage is known as the controlling mechanism of oil recovery in naturally fractured reservoirs. The efficiency of this mechanism is controlled by block-to-block interactions through capillary continuity and/or reinfiltration processes. In this study, at first, several free-fall gravity drainage experiments were conducted on a well-designed three-block apparatus and the role of tilt angle, spacers’ permeability, wettability and effective contact area (representing a different status of the block-to-block interactions between matrix blocks) on the recovery efficiency were investigated. Then, an experimental-based numerical model of free-fall gravity drainage process was developed,... 

    Investigating the Quality of Water in Sangan Iron Ore Tailing Dam for Reuse it to Industrial System

    , M.Sc. Thesis Sharif University of Technology Akbari, Iman (Author) ; Hashemian, Jamaloddin (Supervisor) ; Mohammadi Boghaei, Davar (Co-Advisor)
    In this project some samples from the water which enters the plant and the effluent water were analyzed and the results were compared due to investigating the quality of water in Sangan mine tailing dams. Considering that Northern C mass contains more than two percent sulfur, it can produce AMD. Acid Mine Drainage (AMD), which is caused by the oxidation of sulfide ores in the mines, is the most important environmental problem. Anticipating potential problems of this waste can prevent the problem. To predict it, Acid-Base Accounting (ABA) test was used. The experiment's parameters like Maximum Potential Acidity (MPA) and Neutralization Potential (NP) were measured for more than 130 samples... 

    Spectrophotometric Determination of Ametryn Herbicide in Drainage Water Based on Aggregation of Gold Nanoparticles Capped with Citrate

    , M.Sc. Thesis Sharif University of Technology Rastgar, Mortaza (Author) ; Hormozi-Nezhad, Mohammad Reza (Supervisor) ; Torkian, A (Supervisor)
    Due to vast use of Ametryn herbicide in agricultural and even non-agricultural activities and the possibility of contamination of carp and natural water sources by this herbicide, determination of this herbicide in surface and ground water sources is very important. Therefor introducing simple and sensitive method for determination of Ametryn is critical.
    This study demonstrate a simple and sensitive colorimetric method for the detection and determination of Ametryn based on aggregation of citrate capped AuNPs. Studied method relies upon shape and distance dependent AuNPs surface plasmon resonance. By replacing the sulfide containing Ametryn herbicide with citrate molecules on AuNPs... 

    Experimental study and modeling of gravity drainage during WAG process in fractured carbonate rocks

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 27, Issue 3 , October , 2008 , Pages 103-113 ; 10219986 (ISSN) Jafari, M ; Badakhshan, A ; Taghikhani, V ; Rashtchian, D ; Gotbi, C ; Sajadian, V. A ; Sharif University of Technology
    The experimental study and modeling of gravity drainage during Water Alternative Gas Injection, WAG process, in carbonate rock for one of the Iranian off-shore reservoir at lab-scale were carried out. The mechanism of gravity drainage during the WAG process, and its contribution to the oil recovery in the fractured carbonate reservoirs were also studied. In the WAG process alternatively gas is injected during the process and gravity drainage could be happened. Changes in the block dimensions, rock properties, oil properties, gas properties, and fractures properties and their effect on the amount of oil recovered during the gravity drainage mechanism were studied. It would be worth mentioning... 

    Influence of process variables on biooxidation of ferrous sulfate by an indigenous Acidithiobacillus ferrooxidans. Part I: Flask experiments

    , Article Fuel ; Volume 85, Issue 17-18 , 2006 , Pages 2555-2560 ; 00162361 (ISSN) Mousavi, S. M ; Yaghmaei, S ; Salimi, F ; Jafari, A ; Sharif University of Technology
    Biological oxidation of ferrous sulfate by Acidithiobacillus ferrooxidans has proved to be a significant step in the bioleaching of sulfide minerals and the treatment of acid mine drainage. The same bioreaction also has beneficial applications in the desulphurization of coal and removal of hydrogen sulfide from gaseous effluents. In this research, the effects of some process variables such as pH, temperature, elemental sulfur, amount of initial ferrous and magnesium ions on oxidation of ferrous sulfate by a native A. ferrooxidans, which was isolated from a chalcopyrite concentrate, were investigated. All experiments carried out in shake flasks at 33 °C that was obtained as optimum... 

    An improvement on modeling of forced gravity drainage in dual porosity simulations using a new matrix-fracture transfer function

    , Article Transport in Porous Media ; Volume 94, Issue 1 , 2012 , Pages 207-223 ; 01693913 (ISSN) Samimi, S. E ; Masihi, M ; Gerami, S ; Ghazvini, M. G ; Sharif University of Technology
    In fractured oil reservoirs, the gravity drainage mechanism has great potentials to higher oil recovery in comparison with other mechanisms. Recently, the forced gravity drainage assisted by gas injection has also been considered; however, there are few comprehensive studies in the literature. Dual porosity model, the most common approach for simulation of fractured reservoirs, uses transfer function concept to represent the fluid exchange between matrix and its neighborhood fractures. This study compares the results of different available transfer functions with those of fine grid simulations when forced gravity drainage contributes to oil production from a single matrix block. These...