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    A new insight into pore body filling mechanism during waterflooding in a glass micro-model

    , Article Chemical Engineering Research and Design ; Volume 151 , 2019 , Pages 100-107 ; 02638762 (ISSN) Rezaei Dehshibi, R ; Sadatshojaie, A ; Mohebbi, A ; Riazi, M ; Sharif University of Technology
    Institution of Chemical Engineers  2019
    By displacing oil in porous media with other fluid, different mechanisms of fluid displacing occur. The importance of understanding the trapping mechanisms like pore body filling is irrefutable. Pore body filling mechanism with a coordination number of four has different events like I0, I1, I2 and I3. Previous studies showed that the event of I0 occurs when the pore is only filled by a compressible non-wetting phase, but this study showed that this event could also occur by an incompressible non-wetting phase. Trapping mechanisms can be examined in a glass micro-model. In this research, a glass micro-model with three different patterns was used. Results showed that at two spots of the... 

    Simulation of wetting tendency of fluids with high density ratios using RK Lattice Boltzmann method

    , Article 16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2019, 14 October 2019 through 18 October 2019 ; 2020 Sadeghi, M ; Pak, A ; Sadeghi, H ; Sharif University of Technology
    Asian Regional Conference on Soil Mechanics and Geotechnical Engineering  2020
    Several lattice Boltzmann models for multi-phase flow have been developed, but few of them are capable of modeling fluid flows with high density ratio in the order of 1000. Therefore, an advanced chromodynamics, Rothmann-Keller (RK) type model is employed in current study, which can handle liquid-gas density ratio in the order of 1000 and viscosity ratio in the order of 100. Other distinctive characteristics of the proposed model are high stability, and capability of setting parameters such as surface tension independently. In spite of these benefits, the original RK model fails to model wetting tendency of the fluids. As a result, it is impossible to correctly simulate two-fluid phase flow... 

    Experimental investigation of matrix wettability effects on water imbibition in fractured artificial porous media

    , Article Journal of Petroleum Science and Engineering ; Volume 86-87 , 2012 , Pages 165-171 ; 09204105 (ISSN) Rezaveisi, M ; Ayatollahi, S ; Rostami, B ; Sharif University of Technology
    Spontaneous water imbibition into the matrix blocks is known as the main mechanism for increased oil recovery from naturally fractured oil reservoirs. The rate of oil recovery and its ultimate value is mostly affected by wettability of the rocks and their pore structure. Oil viscosity also greatly influences the rate of oil recovery. A novel experimental model was utilized to study the imbibition mechanism under different wettability conditions. Matrix blocks made from different grain types and size distributions of glass beads were saturated with two different types of synthetic oil, to mimic the oil-saturated matrixes. The wetting characteristic of the models used in this study were... 

    An Analytic Solution for the Frontal Flow Period in 1D Counter-Current Spontaneous Imbibition into Fractured Porous Media Including Gravity and Wettability Effects

    , Article Transport in Porous Media ; Volume 89, Issue 1 , 2011 , Pages 49-62 ; 01693913 (ISSN) Mirzaei Paiaman, A ; Masihi, M ; Standnes, D. C ; Sharif University of Technology
    Including gravity and wettability effects, a full analytical solution for the frontal flow period for 1D counter-current spontaneous imbibition of a wetting phase into a porous medium saturated initially with non-wetting phase at initial wetting phase saturation is presented. The analytical solution applicable for liquid-liquid and liquid-gas systems is essentially valid for the cases when the gravity forces are relatively large and before the wetting phase front hits the no-flow boundary in the capillary-dominated regime. The new analytical solution free of any arbitrary parameters can also be utilized for predicting non-wetting phase recovery by spontaneous imbibition. In addition, a new... 

    Selecting a Surfactant for Wettability Alteration In Iranian Carbonate Reservoirs

    , M.Sc. Thesis Sharif University of Technology Zangeneh Var, Alireza (Author) ; Bastani, Daruoosh (Supervisor) ; Badakhshan, Amir (Supervisor)
    Fractured carbonate reservoirs are mostly oil-wet to intermediate-wet. Due to the negative capillary pressure of the matrix poor spontaneous imbibition of reservoir brine occurs in such reservoirs, and water flooding leads into early break through due to the high conductivity of the fracture network. Some surfactants have the ability to change the wettability of rock matrix toward water-wet state by adsorbing onto the rock surface. The phenomenon can result in spontaneous imbibition improvement and thereby increasing water flooding efficiency and recovery from fractured carbonate reservoirs. In this thesis the effect of some surfactants on the wettability of Iranian carbonate reservoir rocks... 

    Numerical Investigation of Motion of Nanodroplets on Wetting Gradient Surfaces

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Ahmad (Author) ; Moosavi, Ali (Supervisor)
    A droplet placed on the boundary of two solids with different wettabilities will move to the more wettable part. This is a well-known phenomenon and has been extensively used in a variety of processes and applications ranging from biological systems and ink jet printing to the commercial lab-on-a-chip. Because of its importance, many studies are conducted around this phenomenon. The difference between the equilibrium contact angles of the droplet on the two parts gives rise to an interfacial driving force which moves the droplet. Such a motion is not continuous as the droplet slides to the more wettable area, the driving force diminishes and consequently the droplet stops. A non-stop motion... 

    Removal of Fluorine from radioactive solid waste of Esfahan Uranium Conversion Facility

    , M.Sc. Thesis Sharif University of Technology Gerami, Vahid (Author) ; Samadfam, Mohammad (Supervisor) ; Khanchi, Alireza (Supervisor) ; Gasemi, Hosein (Co-Advisor)
    Uranium is the most important element in the nuclear fuel cycle. Recovery of uranium from waste produced at every stage of the fuel cycle is not only economically important, but also environmentally important. In the production phase of uranium hexafluoride, certain amount of solid waste is produced in the bottom of the fluorination reactor. In order to extract the uranium from this waste, we have to eliminate the fluorine contained in the waste. This is because the fluorine forms strong complex with uranyl ions during the extraction process, and prevents from efficient extraction of uranium. In the current thesis؛ first, we examined the characteristics of the waste ... 

    Experimental Study of Improved Oil Recovery by Low-Salinity Waterflooding in Asphaltenic Reservoirs

    , M.Sc. Thesis Sharif University of Technology Rashid, Saeed (Author) ; Ayatollahi, Shahaboddin (Supervisor) ; Vosoughi, Manouchehr (Supervisor)
    There is increasing evidence that injecting modified brines has a significant impact on the amount of oil recovered, but the exact mechanism by which this occurs is an unsettled issue, and is supposed to be a cause of the complex interactions occurring between the phases insitu. In this thesis, surface chemistry of smart water has been investigated. Fluid/solid and fluid/fluid interactions for Bangestan crude oil in tfhe presence of designed solutions and a set of dilutions of Persian Gulf seawater have been studied and compared. Fluid/solid interactions were investigated through wettability studies. Impact of salinity and ionic composition on this interaction was measured through contact... 

    Microorganisms Effects on Interfacial Tension and Wettability During Smart Water Injection in Oil Reservoirs

    , M.Sc. Thesis Sharif University of Technology Jahanbani Veshareh, Moein (Author) ; Ayatollahi, Shahabodin (Supervisor) ; Massihi, Mohsen (Supervisor)
    This research was done for feasibility evaluation and understanding correct microbial enhanced oil recovery(MEOR) procedure for carbonate reservoirs. With the aim of cost reduction and possible activation of smart water mechanisms, sea water used as a base for MEOR process. Two biosurfactant producing strains were isolated from oil contaminated water and soil, and one halotolerant strain, from sea water. Optimization of biosurfactant yield was conducted and two new definitions for optimum point, by considering economical and technical facts, were proposed. Partial characterization of produced biosurfactant was carried out through FTIR and NMR analysis and the produced biosurfactant was... 

    Numerical Study of Anisotropic Wetting of Nano-Droplets on Chemically Patterned Surfaces

    , M.Sc. Thesis Sharif University of Technology Rajabpour, Shahram (Author) ; Moosavi, Ali (Supervisor)
    This study investigates three-dimensional modeling of nanodroplets over chemically patterned surfaces. The pattern can be established by changing the contact angle on the surface. The problem is studied numerically by solving the thin film equations.Both the long-range and short-range inter-molecular interactions are considered. The numerical procedure is validated by using the theoretical studies. The effects of parameters such as the size of the droplets, the gradient of the surface, and the slip coefficient on the dynamics and speed of droplets and the shape of them during the motion are inspected.By examining the dynamics of the system it is revealed that the velocity of the droplets... 

    Experimental Investigation of Oil Production by Low IFT Dynamic Imbibition

    , M.Sc. Thesis Sharif University of Technology Harimi, Behrouz (Author) ; Masihi, Mohsen (Supervisor)
    Imbibition process is known to be an important recovery mechanism in naturally fractured reservoirs with water-wet matrix blocks that are imposed to water influx from an active aquifer or water flooding. Matrix blocks which are subjected to water flooding or water invasion from active aquifers do not become immersed in water at once, but they experience gradual rising of water in fracture. But most of imbibition studies are performed under conditions of totally immersed cores in static aqueous phase. Surfactants are known to reduce residual oil saturation by decreasing interfacial tension (IFT) between oil and water. On the other hand, considerable reduction of IFT due to surfactant... 

    Elastic Properties of Wet Granular Material

    , M.Sc. Thesis Sharif University of Technology Shabannia Roknabadi, Mohammad Reza (Author) ; Rouhani, Shahin (Supervisor)
    To explain the dependence of sliding friction on or between the layers of wet sand, one first needs to have a rather good understanding of the elastic properties of wet granular material. Experimental work that has been done on the subject so far, has shown that these elastic properties have a peculiar dependence on the water volume fraction of the sand system. But till nowno theoretical model has been presented that could illustrate the physical causes of such findings. More specifically, these handful of theoretical models have not been able to explain the complex relationship between the shear modulus of sand and the water volume percentage. In this thesis at first the nature and... 

    An Experimental Study of Oil Production under Spontaneous Co-current Imbibition and Effective Parameters Influencing the Process in Low IFT

    , M.Sc. Thesis Sharif University of Technology Hamidpour, Esmaeil (Author) ; Massihi, Mohsen (Supervisor)
    Capillary Imbibition is an important mechanism in producing oil from matrix blocks in fractured reservoirs. In a water-wet fractured reservoir, if the rise of water level in fracture is in a way that at all the moments the water front in fracture is lower than that in the matrix block we expect co-current imbibition. Iranian reservoirs have large matrix blocks and co-current imbibition can be expectable. Till this time, not many investigations have been done on co-current imbibition in and out of our country, Iran. In this thesis, an experimental investigation on co-current imbibition will be done for different conditions. The main goal of this thesis is the study of co-current imbibition in... 

    Analytical and Experimental Investigation of Scaling the Static and Dynamic Imbibition in Fractured Reservoirs

    , Ph.D. Dissertation Sharif University of Technology Mirzaei-Paiaman, Abouzar (Author) ; Masihi, Mohsen (Supervisor)
    In imbibition process, as one of the main mechanisms of recovery from naturally fractured reservoirs, a wetting fluid enters matrix blocks and produces nonwetting phase from blocks as result of interaction between capillary, gravity and viscous forces. Depending on various characteristics of system different types of imbibition like counter-current spontaneous imbibition, cocurrent spontaneous imbibition and dynamic counter-current imbibition could occur. In order to predict recovery from matrix blocks scaling equations can be used. In this thesis suitable scaling equations are presented for different types of imbibition by using analytical solutions. The studies cases are counter-current... 

    Simulation of Organic/Inorganic Quantum Dot Light Emitting Diodes

    , M.Sc. Thesis Sharif University of Technology Alam, Mohammad Hossein (Author) ; Faez, Rahim (Supervisor)
    The light emitting diodes is composed of an electron transport layer and hole transport layer. The electrons and holes go to the middle region called active region through these transmit regions, and they emit light from themselves by recombination in this area. In our structure, the active region consists of quantum dots. The emitted light characteristics depend on these dots to great extent. In this thesis, we first describe the processes in this type of device, and then we will review the well-known structures that have been reported so far. In chapter 4 discusses the important characteristics of the active region, including the size of the quantum dots and the wetting layer, and we... 

    Experimental Investigation of Asphaltic Sludge Formation Caused by Asphaltenic Oil Carbonated Reservoir Acid Stimulation

    , Ph.D. Dissertation Sharif University of Technology Mohammadzadeh Shirazi, Meisam (Author) ; Ghotbi, Cyrus (Supervisor) ; Ayatollahi, Shahab (Supervisor)
    Acidizing is one of the most effective techniques to remove the formation damage and restore (or even increase) the permeability of the near wellbore region. Although this technique is widely used to resolve the skin problem, it could initiate new damages itself that hinder the fluid flow and decrease the well production, consequently. Acid-oil emulsion and sludge formation are known as two major induced formation damage and the main reasons for the oil well acid treatment failures.When the HCl is reacted with asphaltenic crude oil during matrix acidizing, it results in unexpected damage at the near wellbore region and hinder the fluid flow through certain mechanisms include:
    1- Pore... 

    Modeling Catalyst Deactivation in Catalytic Wet Air Oxidation of Phenol in Fixed Bed Three-Phase Reactors

    , M.Sc. Thesis Sharif University of Technology Golestani, Akram (Author) ; Kazemeini, Mohammad (Supervisor) ; Khorasheh, Farhad (Supervisor)
    In the present work, wet air oxidation of phenol over 7/3 MnO2/CeO2 composite oxide catalyst in trickle-bed and packed-bubble column reactors was modeled. Complexity of wet air oxidation reactions and catalyst poisoning with carbonaceous groups, on the surface and in the pores of catalyst, make the modeling process complicated. Plurality of mass balance equations which are confirmed in the catalyst pellet and in dynamic and static bed phase, also the equation of catalyst deactivation, lead us solve them simultaneously. In addition, the equations are two dimension and unsteady state and carbon of oxidation intermediates are present which make the modeling process more complicated. We are... 

    Investigation of the microscopic displacement mechanisms and macroscopic behavior of alkaline flooding at different wettability conditions in shaly glass micromodels

    , Article Journal of Petroleum Science and Engineering ; Vol. 122, issue , August , 2014 , pp. 595-615 ; ISSN: 09204105 Mehranfar, A ; Ghazanfari, M. H ; Sharif University of Technology
    Among various chemical methods, alkaline flooding has a great potential for enhancing heavy oil recovery, especially for reservoirs which contain acidic crude oil. However, fundamental understanding about microscopic displacement mechanisms and macroscopic behavior during alkaline floods at different wettabilities is not well understood, especially in five-spot shaly models. In this work several alkaline floods are performed on a glass micromodel containing randomly distributed shale streaks at different wettability conditions. Various mechanisms responsible for enhancing heavy oil recovery during alkaline flooding are investigated at different wettability conditions. These mechanisms... 

    Dewetting of evaporating thin films over nanometer-scale topographies

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Vol. 90, issue. 1 , July , 2014 ; ISSN: 15393755 Akbarzadeh, A. M ; Moosavi, A ; Moghimi Kheirabadi, A ; Sharif University of Technology
    A lubrication model is used to study dewetting of an evaporating thin film layer over a solid substrate with a nanometer-scale topography. The effects of the geometry of the topography, the contact angle, the film thickness, and the slippage on the dewetting have been studied. Our results reveal that the evaporation enhances the dewetting process and reduces the depinning time over the topography. Also it is shown that the depinning time is inversely proportional to the slippage and increasing the contact angle may considerably reduce the depinning time, while the film thickness increases the depinning time  

    Characterization of the effect of disturbance on the hydro-mechanical behavior of a highly collapsible loessial soil

    , Article Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014 ; Vol. 1, issue , 2014 , p. 261-266 Haeri, S. M ; Khosravi, A ; Ghaizadeh, S ; Garakani, A. A ; Meehan, C. L ; Sharif University of Technology
    Highly collapsible loessial soils are characterized by an open void structure that can experience significant settlement upon loading. In the field, these partially saturated Aeolian deposits are particularly susceptible to wetting-induced collapse. Due to difficulties in preparing undisturbed specimens from highly collapsible soils, previous studies have generally performed laboratory tests on reconstituted specimens with different water contents and densities, and the effect of disturbance on the initial state of the soil was ignored. Disturbance in highly collapsible soil specimens may significantly affect the natural composition of the soil matrix, the non-homogeneous distribution of...