Search for: mechanical-permeability
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    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
    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... 

    Analytical derivation of tortuosity and permeability of monosized spheres: A volume averaging approach

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 83, Issue 2 , February , 2011 ; 15393755 (ISSN) Ahmadi, M. M ; Mohammadi, S ; Hayati, A. N ; Sharif University of Technology
    Macroscopic properties of granular materials are important in modeling a variety of flow and transport phenomena in many fields of science. Determination of these parameters has always been an issue among both researchers and engineers, mainly in view of tortuosity and permeability. This paper presents analytical functions for the tortuosity and permeability of monosized sphere arrays based on a volume averaging approach and eliminates some ambiguities by modification of the original representative elementary volume model. Veracity of the proposed formulations has been illustrated through comparisons with the latest available results on the subject. Good agreement is found  

    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
    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... 

    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
    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... 

    Transient thermo-poroelastic analysis of drilling-induced mechanical damage in nonfractured rocks

    , Article Arabian Journal of Geosciences ; Volume 8, Issue 12 , 2015 , Pages 10803-10818 ; 18667511 (ISSN) Gomar, M ; Goodarznia, I ; Shadizadeh, S. R ; Sharif University of Technology
    Springer Verlag  2015
    Permeability variations in reservoirs and around boreholes are of great interest in petroleum engineering due to the fact that they can significantly affect reserve estimates, reservoir development, well production or injection rate, and the likely success of remedial actions of near-wellbore damage. A fully coupled transient thermo-poroelastic concept with and without rock mechanical damage models is employed to evaluate stress distribution and permeability variation around the boreholes and breakouts. The anisotropy concept is applied to permeability, rock modulus, and uniaxial compressive strength using Weibull distribution. The Mogi–Coulomb failure criterion is employed to model breakout... 

    A comparison of different geometrical elements to model fluid wicking in paper-based microfluidic devices

    , Article AIChE Journal ; Volume 66, Issue 1 , 2020 Boodaghi, M ; Shamloo, A ; Sharif University of Technology
    John Wiley and Sons Inc  2020
    Recently, microfluidic paper-based analytical devices (μPADs) have outstripped polymeric microfluidic devices in the ease of fabrication and simplicity. Surface tension-based fluid motion in the paper's porous structure has made the paper a suitable substrate for multiple biological assays by directing fluid into multiple assay zones. The widespread assumption in most works for modeling wicking in a paper is that the paper is a combination of capillaries with the same diameter equal to the effective pore diameter. Although assuming paper as a bundle of capillaries gives a good insight into pressure force that drives the fluid inside the paper, there are some difficulties using the effective... 

    Modeling of permeability with the aid of 3D interdendritic flow simulation for equiaxed dendritic structures

    , Article Materials Science and Engineering A ; Volume 475, Issue 1-2 , 2008 , Pages 355-364 ; 09215093 (ISSN) Khajeh, E ; Mirbagheri, S. M. H ; Davami, P ; Sharif University of Technology
    In this study, the permeability for interdendritic liquid flow through equiaxial mushy zone has been modeled and experimentally measured. In the present work, by applying a virtual dendrite in a micro-domain and solving Navier-Stokes equation, flow pattern around the dendrite has been obtained and then by applying Darcy's law to this 3D domain the permeability has been determined. In this micro-model the influence of solid fraction and geometry of dendrites have been assessed. Numerically determined values of permeabilities have been analyzed by the use of SPSS statistical software. Then an experimental method is used to measure the permeability for flow through equiaxial mushy zone of Pb-Sn... 

    Simulation of Si concentration effect on the permeability for columnar dendrite structures during solidification of Al-Si alloy

    , Article Materials and Design ; Volume 28, Issue 1 , 2007 , Pages 356-361 ; 02613069 (ISSN) Mirbagheri, S. M. H ; Silk, J ; Sharif University of Technology
    Elsevier Ltd  2007
    A numerical model has been developed for the determination of liquid flow permeability through columnar dendrite during growth and segregation in Al-Si mushy alloys. The model is inclusive of two stages, first numerical evolution of the dendrite shape during growth, and second numerical determination of the permeability. Simulation results shown which Si concentration by transform of dendrite shape dendrite could reduce of the interdendritic liquid permeability. © 2005 Elsevier Ltd. All rights reserved  

    LBM simulation of electro-osmotic flow (EOF) in nano/micro scales porous media with an inclusive parameters study

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Vol. 7 , November , 2014 ; ISBN: 9780791849545 Zakeri, R ; Lee, E. S ; Salimi, M. R ; Sharif University of Technology
    In this paper, we present our results about simulation of 2D-EOF in Nano/Micro scales porous media using lattice Boltzmann method (LBM) in micro-channel for EOF. The high efficient numerical code use strongly high nonlinear Poisson Boltzmann equation to predicate behavior of EOF in complex geometry. The results are developed with precisely investigation of several effective parameters on permeability of EOF, such as geometry (channel height and number and location of charge), external electric field, thickness of Debye length (ionic concentration), and zeta potential. Our results are in excellent agreement with available analytical results. Our results show that for certain external electric... 

    An Artificial Neural Networks Model for Predicting Permeability Properties of Nano Silica-Rice Husk Ash Ternary Blended Concrete

    , Article International Journal of Concrete Structures and Materials ; Volume 7, Issue 3 , September , 2013 , Pages 225-238 ; 22341315 (ISSN) Najigivi, A ; Khaloo, A ; Iraji zad, A ; Abdul Rashid, S ; Sharif University of Technology
    Korea Concrete Institute  2013
    In this study, a two-layer feed-forward neural network was constructed and applied to determine a mapping associating mix design and testing factors of cement-nano silica (NS)-rice husk ash ternary blended concrete samples with their performance in conductance to the water absorption properties. To generate data for the neural network model (NNM), a total of 174 field cores from 58 different mixes at three ages were tested in the laboratory for each of percentage, velocity and coefficient of water absorption and mix volumetric properties. The significant factors (six items) that affect the permeability properties of ternary blended concrete were identified by experimental studies which were:... 

    The corrosion investigation of rebar embedded in the fibers reinforced concrete

    , Article Construction and Building Materials ; Volume 35 , October , 2012 , Pages 564-570 ; 09500618 (ISSN) Kakooei, S ; Akil, H. M ; Dolati, A ; Rouhi, J ; Sharif University of Technology
    Elsevier  2012
    One effective method for preventing corrosion of steel reinforcement and improving the mechanical properties of concrete is changing the physical nature of concrete by adding different materials. In this study, we have used polypropylene fibers as an additional material. We have compared the corrosion rate of rebar using different volume ratios and sizes of polypropylene fibers. Reinforcement potential increased as the amount of fibers increased from 0 to 2 kg m -3. The polypropylene fibers delay the initial corrosion process by preventing cracking, thereby decreasing permeability of the concrete. In addition, the corrosion rate of concrete samples made with Kish Island coral aggregate was... 

    Identification of flow units using methods of testerman statistical zonation, flow zone index, and cluster analysis in tabnaak gas field

    , Article Journal of Petroleum Exploration and Production Technology ; Volume 6, Issue 4 , 2016 , Pages 577-592 ; 21900558 (ISSN) Mahjour, S. K ; Ghasem Al Askari, M. K ; Masihi, M ; Sharif University of Technology
    Springer Verlag 
    The relation between porosity and permeability parameters in carbonated rocks is complicated and indistinct. Flow units are defined with aim of better understanding reservoir unit flow behavior and relation between porosity and permeability. Flow units reflect a group of rocks with same geological and physical properties which affect fluid flow, but they do not necessarily coincide with boundary of facies. In each flow unit homogeneity of data is preserved and this homogeneity fades in the boundaries. Here, in this study, three methods are used for identification of flow units and estimation of average porosity and permeability in three wells of Tabnaak gas field located in south of Iran.... 

    Fully coupled analysis of interaction between the borehole and pre-existing fractures

    , Article International Journal of Rock Mechanics and Mining Sciences ; Volume 89 , 2016 , Pages 151-164 ; 13651609 (ISSN) Gomar, M ; Goodarznia, I ; Shadizadeh, S. R ; Sharif University of Technology
    Elsevier Ltd  2016
    The coupling of rock and thermal stresses along with fluid pressure are particularly important in fractured rock masses, since stress-induced changes in permeability can be large and irreversible under perturbations resulting from various natural and induced activities. A new method is presented to model fracture permeability changes during drilling in fractured rocks. The approach includes finite element method (FEM) for fully coupled thermo-poroelastic analysis of stress distribution around borehole and displacement discontinuity method (DDM) to model fracture deformation. Three cases of overbalanced, underbalanced, and balanced drilling fluid pressure conditions are employed. The... 

    A priori error estimation of upscaled coarse grids for water-flooding process

    , Article Canadian Journal of Chemical Engineering ; Volume 94, Issue 8 , 2016 , Pages 1612-1626 ; 00084034 (ISSN) Khoozan, D ; Firoozabadi, B ; Sharif University of Technology
    Wiley-Liss Inc 
    Advanced reservoir characterization methods can yield geological models at a very fine resolution, containing 1011–1018 cells, while the common reservoir simulators can only handle much lower numbers of cells due to computer hardware limitations. The process of coarsening a fine-scale model to a simulation model is known as upscaling. Predicting the accuracy of simulation results over an upscaled grid with respect to the fine grid is highly important, as it can yield the optimum upscaling process. In this paper, permeability-based and velocity-based a priori error estimation techniques are proposed by introducing image processing-based comparison methods in the context of upscaling. The... 

    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
    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... 

    Performance improvement of MgO-C refractory bricks by the addition of Nano-ZrSiO4

    , Article Materials Chemistry and Physics ; Volume 202 , 2017 , Pages 369-376 ; 02540584 (ISSN) Gheisari Dehsheikh, H ; Ghasemi Kahrizsangi, S ; Sharif University of Technology
    Many benefits of the MgO-C refractory bricks such as excellent corrosion resistance, high thermal shock resistance, good mechanical strength at high temperatures, and permeability have attracted attention of consumers in various industries. But on the other hand, the low oxidation resistance of these refractory bricks at high temperatures has restricted their application. For this purpose, in this research study, the impact of Nano-ZrSiO4 addition on microstructure and performance of MgO-C refractory was investigated. 0, 0.5, 1, 1.5, and 2 wt % of Nano-ZrSiO4 was added to compositions. After samples preparation, all specimens tempered and fired (in a coke bed) at the 250 °C and 1600 °C for 8... 

    Unidirectional surface waves in bi-anisotropic media

    , Article IEEE Journal of Quantum Electronics ; Volume 54, Issue 6 , 2018 ; 00189197 (ISSN) Karimi, P ; Rejaei, B ; Khavasi, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    We show theoretically that unidirectional surface waves can propagate on the surface of homogeneous bi-anisotropic layers with an anti-symmetric chirality tensor. These materials mimic the electromagnetic behavior of an anisotropic medium with gyrotropic permittivity and permeability tensors that operate on pseudo-electromagnetic fields. The unidirectional waves have transverse pseudo-electric or magnetic polarizations and pass through an obstacle without backscattering if the obstacle does not cause polarization change. The bi-anisotropic medium can be realized as a metamaterial comprising omega particles tailored to achieve the constitutive parameters desired. © 2018 IEEE  

    Characterization and estimation of reservoir properties in a carbonate reservoir in Southern Iran by fractal methods

    , Article Journal of Petroleum Exploration and Production Technology ; Volume 8, Issue 1 , 2018 , Pages 31-41 ; 21900558 (ISSN) Rahimi, R ; Bagheri, M ; Masihi, M ; Sharif University of Technology
    Springer Verlag  2018
    Reservoir heterogeneity has a major effect on the characterization of reservoir properties and consequently reservoir forecast. In reality, heterogeneity is observed in a wide range of scales from microns to kilometers. A reasonable approach to study this multi-scale variations is through fractals. Fractal statistics provide a simple way of relating variations on larger scales to those on smaller scales and vice versa. Simple statistical fractal models (fBm and fGn) can be useful to understand the model construction and help the reservoir structure characterization. In this paper, the fractal methods (fGn and fBm) have been applied to characterize and to estimate of reservoir properties.... 

    Pore-scale modeling of rarefied gas flow in fractal micro-porous media, using lattice Boltzmann method (LBM)

    , Article Journal of Thermal Analysis and Calorimetry ; Volume 135, Issue 3 , 2019 , Pages 1931-1942 ; 13886150 (ISSN) Rostamzadeh, H ; Salimi, M. R ; Taeibi Rahni, M ; Sharif University of Technology
    Springer Netherlands  2019
    Due to the widespread use of rarefied gas flow in micro-porous media in industrial and engineering problems, a pore-scale modeling of rarefied gas flow through two micro-porous media with fractal geometries is presented, using lattice Boltzmann method. For this purpose, square- and circular-based Sierpinski carpets with fractal geometries are selected due to their inherent behavior for real porous media. Diffusive reflection slip model is used and developed for these porous media through this study. With this respect, the planar Poiseuille flow is selected as a benchmark and validated with the literature. The effect of Knudsen number (Kn) on the permeability is investigated and compared in... 

    Vorticity-based coarse grid generation for upscaling two-phase displacements in porous media

    , Article Journal of Petroleum Science and Engineering ; Volume 59, Issue 3-4 , 2007 , Pages 271-288 ; 09204105 (ISSN) Ashjari, M. A ; Firoozabadi, B ; Mahani, H ; Khoozan, D ; Sharif University of Technology
    Coarse grid generation from finely gridded geological model is a main step in reservoir simulation. Coarse grid generation algorithms aim at optimizing size, number and location of the grid blocks by identifying the important geological and flow features which control flow in porous media. By optimizing coarse grid structure we can improve accuracy of the coarse scale simulation results to reproduce fine grid behavior. A number of techniques have been proposed in the literature. We present a novel coarse grid generation procedure based on vorticity preservation between fine and coarse grids. In the procedure, the coarse grid mesh tries to capture variations in both permeability and fluid...