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    Numerical investigation into the effects of geometrical and loading parameters on lateral spreading behavior of liquefied layer

    , Article Acta Geotechnica ; 2013 , Pages 1-13 ; 18611125 (ISSN) Pak, A ; Seyfi, S ; Ghassemi, A ; Sharif University of Technology
    2013
    Abstract
    Numerical simulation of liquefaction-induced lateral spreading in gently sloped sandy layers requires fully coupled dynamic hydro-mechanical analysis of saturated sandy soil subjected to seismic loading. In this study, a fully coupled finite element model utilizing a critical-state two-surface-plasticity constitutive model has been applied to numerically investigate the effects of surface/subsurface geometry on lateral spreading. Using a variable permeability function with respect to excess pore pressure ratio is another distinctive feature of the current study. The developed code has been verified against the results of the well-known VELACS project. Lateral spreading phenomenon has been... 

    Physical properties and applications of clay nanofiller/epoxy nanocomposites

    , Article Physical Properties and Applications of Polymer Nanocomposites ; 2010 , Pages 743-772 ; 9781845696726 (ISBN) Marouf, B. T ; Bagheri, R ; Sharif University of Technology
    Abstract
    The physical properties including glass transition temperature and permeability behavior of clay-filled epoxies are reviewed in this chapter. There is no consensus in the literature on how nanoclay affects the α-relaxation temperature in epoxy systems. This perhaps rises from the complexity of nanoclay morphology in polymeric resins and the interphase properties since morphology of nanoclay and interphase characteristics are two key parameters to control the glass transition process in epoxy nanocomposites. In addition, the possible existence of several α-transitions in montmorillonite-filled epoxies due to the existence of several relaxation domains may account for the controversial... 

    The dependency of relative permeability on dominated flow regimes under gas gravity assisted flow

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 33, Issue 2 , Oct , 2011 , Pages 101-113 ; 15567036 (ISSN) Rostami, B ; Kharrat, R ; Pooladi Darvish, M ; Ghotbi, C ; Sharif University of Technology
    2011
    Abstract
    Gas-oil relative permeability is essential for performance predictions of reservoirs with solutions for gas drive, gas cap expansion, or gas injection. The nature of flow in reservoir is determined by the interplay of relative permeability and viscous, gravity, and capillary forces. Displacement experiments of the gas-oil system are performed on long core scale models by varying the petrophysical properties and flow conditions. Experiments are conducted in situations where capillary, gravity, and viscous forces are comparable. The effect of destabilized front velocity on relative permeability and residual saturation is investigated. The results indicate that the relative permeability varies... 

    Relative permeability estimation of porous media: Comparison of implicit and explicit approaches

    , Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) Ghazanfari, M. H ; Rashtchian, D ; Kharrat, R ; Vossoughi, S ; Khodabakhsh, M ; Taheri, S ; Sharif University of Technology
    2006
    Abstract
    Relative permeability is used to describe quantitatively simultaneous transport of two or more immiscible phases through a porous medium. Accurate estimates of relative permeability curves depend on the method of estimation and are desired to obtain reliable predictions of flow behavior. To compare the accuracy of relative permeability estimation of implicit and explicit methods, primary drainage experiments of water by a sample oil fluid have been studied. The experiments performed on a horizontal glass type micromodel as a model of porous media sample under different fixed high flow rates condition to negate capillary pressure effects. The relative permeability of oil and water phases is... 

    Estimation of the Effective Permeability of Heterogeneous Porous Media by Using Percolation Concepts

    , Article Transport in Porous Media ; Volume 114, Issue 1 , 2016 , Pages 169-199 ; 01693913 (ISSN) Masihi, M ; Gago, P. A ; King, P. R ; Sharif University of Technology
    Springer Netherlands  2016
    Abstract
    In this paper we present new methods to estimate the effective permeability (keff) of heterogeneous porous media with a wide distribution of permeabilities and various underlying structures, using percolation concepts. We first set a threshold permeability (kth) on the permeability density function and use standard algorithms from percolation theory to check whether the high permeable grid blocks (i.e., those with permeability higher than kth) with occupied fraction of “p” first forms a cluster connecting two opposite sides of the system in the direction of the flow (high permeability flow pathway). Then we estimate the effective permeability of the heterogeneous porous media in different... 

    Experimental investigation of asphaltene-induced core damage during miscible CO2 injection

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 13 , 2014 , pp. 1395-1405 ; ISSN: 15567036 Bolouri, H ; Ghoodjani, E ; Sharif University of Technology
    Abstract
    In this article, dynamic core flood experiments in miscible CO2 condition were carried out to investigate core damage due to asphaltene deposition. Carbonate and sandstone cores were used to study of effect of core characteristic on permeability and porosity reduction. The experimental results show asphaltene deposition preferentially in sandstone core type takes place in the first half of the core while in the carbonate one it occurs in the second half. In spite of asphaltene content measurement results (IP-143) that show higher asphaltene deposition in sandstone cores, permeability impairment compared to the carbonate one is severe. Also, permeability-porosity reduction models are affected... 

    An experimental and modeling study of asphaltene deposition due to CO 2 miscible injection

    , Article Petroleum Science and Technology ; Volume 31, Issue 2 , 2013 , Pages 129-141 ; 10916466 (ISSN) Bolouri, H ; Schaffie, M ; Kharrat, R ; Ghazanfari, M. H ; Ghoodjani, E ; Sharif University of Technology
    2013
    Abstract
    The authors studied deposition and entrainment of asphaltene particles as major mechanisms that occur in porous media. Deposition mechanisms that contribute to permeability reduction and entrainment of deposited particle improve the damaged permeability value. While in most previous works the effects of entrainment mechanism are considered negligible, in this study miscible CO2 injection tests were conducted by core flood apparatus to investigate the effect of asphaltene deposition on permeability and porosity alterations. Results indicated that proposed model for entrainment mechanism is affected by deposition mechanism. The asphaltene deposition core's characteristics have undeniable roles... 

    Experimental investigation of near miscibility effect on relative permeability curves

    , Article 74th European Association of Geoscientists and Engineers Conference and Exhibition 2012 Incorporating SPE EUROPEC 2012: Responsibly Securing Natural Resources, 4 June 2012 through 7 June 2012 ; June , 2012 , Pages 5469-5474 ; 9781629937908 (ISBN) Parvazdavani, M ; Masihi, M ; Ghazanfari, M. H ; Sharif University of Technology
    European Association of Geoscientists and Engineers, EAGE  2012
    Abstract
    The requirement of reliable relative permeability data is more intensified when the miscibility condition approaches. In this work the relative permeability of CO2 and oil has been measured at different miscibility conditions using conventional methods. Fractured dolomite and sandstone core plugs samples were used in the experiments. Due to some errorful assumptions of conventional methods such as immiscible, incompressible displacement, inverse modeling was used for predicting the reliable relative permeability of oil and gas phases at near miscible condition from measured oil production and pressure drop data. The initial guesses of relative permeabilities were provided from conventional... 

    Application of artificial neural network for estimation of formation permeability in an iranian reservoir

    , Article 1st International Petroleum Conference and Exhibition, Shiraz, 4 May 2009 through 6 May 2009 ; 2009 Yeganeh, M ; Masihi, M ; Fatholahi, S ; Sharif University of Technology
    European Association of Geoscientists and Engineers, EAGE  2009
    Abstract
    The permeability is one of the most important reservoir parameters and its accurate prediction is necessary for reservoir management and enhancement. Although many empirical formulas are derived regarding permeability and porosity in sandstone reservoirs [1], these correlations cannot be modified accurately in carbonate reservoir for the wells which are not cored and there is no welltest data. Therefore estimation of these parameters is a challenge in reservoirs with no coring sample and welltest data. One of the most powerful tools to estimate permeability from well logs is Artificial Neural Network (ANN) whose advantages and disadvantages have been discussed by several authors [2]. In this... 

    A study of a polymeric membrane performance in an ultrafiltration system to use in industrial application

    , Article Desalination and Water Treatment ; Volume 53, Issue 2 , Sep , 2015 , Pages 340-351 ; 19443994 (ISSN) Reyhani, A ; Rajaei, F ; Shahmoradi, M ; Kahkesh, A ; Sharif University of Technology
    Taylor and Francis Inc  2015
    Abstract
    The performance of a polymeric membrane in an ultrafiltration system under the chosen optimum conditions was studied. To achieve this, four real produced waters were dealt with. To find the optimum conditions, Taguchi method was applied. Results showed that PAN350 membrane is a potential candidate for industrial applications for three feeds which contained oil and total organic carbon (TOC) less than 1,500 and 300 ppm, respectively. The values of oil/grease, total suspended solids, and turbidity rejections were approximately 100%. Although TOC could not be entirely removed, the removal values for TOC were acceptable in this study. For the fourth feed due to the values of oil and TOC which... 

    Plasticization effect on performance of polyphenylene oxide hollow fiber membrane at high concentrations of hydrogen sulfide

    , Article 19th International Congress of Chemical and Process Engineering, CHISA 2010 and 7th European Congress of Chemical Engineering, ECCE-7, 28 August 2010 through 1 September 2010 ; 2010 Savoji, H ; Niknejad, S. M. S ; Soltanieh, M ; Sharif University of Technology
    Abstract
    Natural gas contains several impurities, e.g., CO 2 and H 2S, which have undesirable effects on the performance of the glassy polymeric membranes. The plasticization effect of H 2S at high concentrations on the gas separation performance of polyphenylene oxide hollow fiber membrane has been studied at different compositions of H 2S and feed pressures. The existence of high concentrations of H 2S in CH 4 feed mixture, which is present in many natural gas sources in Iran, enhances plasticization. For a H 2S/CH 4 mixture containing 5008 ppm H 2S at ≈ 75 psig, the H 2S permeance reduces by > 45% from its initial value. H 2S acts as a plasticizer in H 2S/CH 4 membrane separation at elevated... 

    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
    Abstract
    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... 

    Wettability alteration of reservoir rocks to gas wetting condition: a comparative study

    , Article Canadian Journal of Chemical Engineering ; Volume 96, Issue 4 , April , 2018 , Pages 997-1004 ; 00084034 (ISSN) Erfani Gahrooei, H. R ; Ghazanfari, M. H ; Karimi Malekabadi, F ; Sharif University of Technology
    Wiley-Liss Inc  2018
    Abstract
    Productivity of gas condensate reservoirs reduces significantly due to the near wellbore condensate/water blockage phenomenon. A novel, permanent solution to alleviate this problem is near wellbore wettability alteration of reservoir rocks to preferentially gas wetting conditions; industrial chemical materials are good candidates for this purpose, because of their eco-friendly characteristics, economical price, and mass production. In this paper, a comparative study is conducted on two industrial fluorinated chemicals, MariSeal 800 and SurfaPore M. Static and dynamic contact angle measurements, spontaneous imbibition, and core flooding tests were conducted to investigate the effect of... 

    Experimental study of sand production and permeability enhancement of unconsolidated rocks under different stress conditions

    , Article Journal of Petroleum Science and Engineering ; Volume 181 , 2019 ; 09204105 (ISSN) Zivar, D ; Shad, S ; Foroozesh, J ; Salmanpour, S ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    Production of sand is a common issue in oil and gas fields causing various production problems. However, as a result of sand production, rock permeability can also be increased at near-wellbore areas, which is considered to be an advantage of solid particles production. Therefore, this study aims to investigate sand production behavior and permeability changes during sand production experimentally. To do so, a specific core flooding system capable of applying different radial and axial stresses has been designed which is equipped with a special fluid distributer at the outlet to prevent any sand particle blockage during fluid production. As part of this study, eleven unconsolidated synthetic... 

    Experimental Investigation of Brine Salinity Effect on Relative Permeability Curve in Tight Reservoir

    , M.Sc. Thesis Sharif University of Technology Zeinolabedin, Roham (Author) ; Shad, Saeed (Supervisor)
    Abstract
    An experimental study was conducted to investigate the reduction of relative permeability caused by salt precipitation. Series of isothermal sand pack flood experiments were conducted on a sand pack composed of several minerals and relative permeability of the involved phases were determined. This compose was taken south of Iranian reservoir properties. A stainless steel sand-pack of 2.5cm internal diameter and 19.2 cm long was designed and built for experimental procedure. There are is different methods to determine relative permeability of porous media, According to available facilities in the lab and objective of this study unsteady state have been chosen to determine relative... 

    3D steady state seepage analysis of embankment dams

    , Article Electronic Journal of Geotechnical Engineering ; Volume 10 F , 2005 ; 10893032 (ISSN) Soleimanbeigi, A ; Jafarzadeh, F ; Sharif University of Technology
    2005
    Abstract
    Steady state seepage analysis of embankment dams is one of the most significant stages in the designing process. Currently, most seepage modeling of embankment dams is performed in two dimensions, often for the highest section, which include several simplifications. In this way, the effect of watertight elements such as grouting curtains in side abutments as well as their material properties is not taken into account in seepage analysis results. Especially if the dam is located in a narrow valley or the effect of existing faults beneath the dam is to be investigated, the results of the two-dimensional seepage analysis differ from those of three-dimensional (3D). In this paper, the... 

    The estimation of formation permeability in a carbonate reservoir using an artificial neural network

    , Article Petroleum Science and Technology ; Vol. 30, issue. 10 , Apr , 2010 , p. 1021-1030 ; ISSN: 10916466 Yeganeh, M ; Masihi, M ; Fatholah,i S ; Sharif University of Technology
    Abstract
    Reservoir permeability is an important parameter that its reliable prediction is necessary for reservoir performance assessment and management. Although many empirical formulas are derived regarding permeability and porosity in sandstone reservoirs, these correlations cannot be accurately depicted in carbonate reservoir for the wells that are not cored and for which there are no welltest data. Therefore, having a framework for estimation of these parameters in reservoirs with neither coring samples nor welltest data is crucial. Rock properties are characterized by using different well logs. However, there is no specific petrophysical log for estimating rock permeability; thus, new methods... 

    The estimation of formation permeability in a carbonate reservoir using an artificial neural network

    , Article Petroleum Science and Technology ; Volume 30, Issue 10 , 2012 , Pages 1021-1030 ; 10916466 (ISSN) Yeganeh, M ; Masihi, M ; Fatholahi, S ; Sharif University of Technology
    2012
    Abstract
    Reservoir permeability is an important parameter that its reliable prediction is necessary for reservoir performance assessment and management. Although many empirical formulas are derived regarding permeability and porosity in sandstone reservoirs, these correlations cannot be accurately depicted in carbonate reservoir for the wells that are not cored and for which there are no welltest data. Therefore, having a framework for estimation of these parameters in reservoirs with neither coring samples nor welltest data is crucial. Rock properties are characterized by using different well logs. However, there is no specific petrophysical log for estimating rock permeability; thus, new methods... 

    A flat polymeric membrane sensor for carbon dioxide/nitrogen gas mixture

    , Article Chemical Engineering Communications ; Volume 204, Issue 4 , 2017 , Pages 445-452 ; 00986445 (ISSN) Shabani, E ; Mousavi, S. A ; Shojaei, A ; Sharif University of Technology
    Taylor and Francis Ltd  2017
    Abstract
    A gas sensor was developed to measure the concentration of binary gas mixtures. This sensor works based on the permeability change of different gas mixtures across the polymeric membranes. Although high values of permeability and selectivity are needed for an ideal separation, the performance of this sensor mainly depends on the permeability factor. Polysulfone and silicone rubber were applied as the membrane base and coat, respectively. Moreover, in contrast to existing polymeric sensors that use hollow fibers, the present sensor is made of flat membranes. This new design is cheaper, smaller, and easier to use in comparison to the hollow fiber polymeric sensors. In order to test the sensor... 

    Analysis of near well-bore behavior of gas condensate reservoir in production stage

    , Article Petroleum Science and Technology ; Volume 30, Issue 24 , 2012 , Pages 2594-2603 ; 10916466 (ISSN) Allahyari, M ; Aminshahidy, B ; Sanati, A ; Taghikhani, V ; Sharif University of Technology
    2012
    Abstract
    The formation of condensate banking in the near well-bore region will lead to the reduction in gas relative permeability and loss of well deliverability. This loss is investigated by conducting a series of fine grid numerical compositional simulation with the gas condensate and dry gas reservoir data. Also, a method for calculation of condensate blockage skin factor is introduced in which the skin factor is calculated using dry gas and gas condensate simulation production data. The authors also found that absolute permeability and pressure drawdown of the producing well have significant influence on the well gas deliverability and condensate blockage skin factor