Search for: fractured-medium
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    Immiscible Displacement of a Wetting Fluid by a Non-wetting One at High Capillary Number in a Micro-model Containing a Single Fracture

    , Article Transport in Porous Media ; Volume 94, Issue 1 , 2012 , Pages 289-301 ; 01693913 (ISSN) Kamari, E ; Rashtchian, D ; Shadizadeh, S. R ; Sharif University of Technology
    Most reservoirs in Iran are heterogeneous fractured carbonate reservoirs. Heterogeneity causes an earlier breakthrough and an unstable front which leads to a lower recovery. A series of experiments were conducted whereby the distilled water displaced n-Decane in strongly oil-wet glass micro-models containing a single fracture. Experimental data from image analysis of immiscible displacement processes are used to modify the Buckley-Leverett and fractional flow equations by a heterogeneity factor. It is shown that the heterogeneity factor in the modified equations can be expressed as a function of fracture length and orientation  

    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... 

    Analytical and Experimental Study to Predict the Residual Resistance Factor on Polymer Flooding Process in Fractured Medium

    , Article Transport in Porous Media ; Volume 85, Issue 3 , 2010 , Pages 825-840 ; 01693913 (ISSN) Ahmad Ramazani, S. A ; Nourani, M ; Emadi, M. A ; Jafari Esfad, N ; Sharif University of Technology
    The major objectives of this study are to analytically and experimentally determine the residual resistance factor in the fractured medium based on the polymer solution properties and operational conditions. The parameters considered in this study are the polymer concentration, power law constitutive equation parameter, and salt concentration, sulfonation content of polymer, temperature, and molecular weight of the water soluble polymers which are used in polymer flooding for enhanced oil recovery. The results indicated that residual resistance factor in fractured medium is dependent on the coil overlap parameter and power law equation parameter of polymer. The coil overlap parameter is a... 

    Integration of adaptive neuro-fuzzy inference system, neural networks and geostatistical methods for fracture density modeling

    , Article Oil and Gas Science and Technology ; Vol. 69, issue. 7 , 2014 , pp. 1143-1154 ; ISSN: 12944475 Jafari, A ; Kadkhodaie-Ilkhchi, A ; Sharghi, Y ; Ghaedi, M ; Sharif University of Technology
    Image logs provide useful information for fracture study in naturally fractured reservoir. Fracture dip, azimuth, aperture and fracture density can be obtained from image logs and have great importance in naturally fractured reservoir characterization. Imaging all fractured parts of hydrocarbon reservoirs and interpreting the results is expensive and time consuming. In this study, an improved method to make a quantitative correlation between fracture densities obtained from image logs and conventional well log data by integration of different artificial intelligence systems was proposed. The proposed method combines the results of Adaptive Neuro-Fuzzy Inference System (ANFIS) and Neural... 

    Experimental and numerical investigation of polymer flooding in fractured heavy oil five-spot systems

    , Article Journal of Petroleum Science and Engineering ; Volume 108 , 2013 , Pages 370-382 ; 09204105 (ISSN) Sedaghat, M. H ; Ghazanfari, M. H ; Masihi, M ; Rashtchian, D ; Sharif University of Technology
    Microscopic and macroscopic displacements of polymer flooding to heavy oil at various levels of salinity and connate water saturation have been investigated. Both oil-wet and water-wet conditions in fractured five-spot micromodel systems, initially saturated with the heavy crude oil are utilized. The primary contribution is to examine the role of salinity, wettability, connate water, and fracture geometry in the recovery efficiency of the system. The microscopic results revealed that the increase in the connate water saturation decreases the oil recovery, independent of the wettability conditions. Moreover, the increase in salinity of the injected fluids lowers the recovery efficiency due to... 

    An experimental investigation of fracture physical properties on heavy oil displacement efficiency during solvent flooding

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 33, Issue 21 , 2011 , Pages 1993-2004 ; 15567036 (ISSN) Farzaneh, S. A ; Dehghan, A. A ; Kharrat, R ; Ghazanfari, M. H ; Sharif University of Technology
    This work is concerned with the role of geometrical properties of fractures on oil displacement efficiency during solvent injection to heavy oil. Here, a series of solvent injection processes were conducted on one-quarter five-spot fractured micromodels that were initially saturated with the heavy oil, at a fixed flow rate condition. The oil recovery was measured using image analysis of the continuously provided pictures. The results show that for the range of experiments performed here, the maximum oil recovery happens at a fracture orientation angle of 45 degrees. Also, increasing the number of fractures leads to a higher oil recovery factor by solvent in 45 degrees, while it does not... 

    A new mathematical model for force gravity drainage in fractured porous media

    , Article Transport in Porous Media ; Volume 83, Issue 3 , 2010 , Pages 711-724 ; 01693913 (ISSN) Ganjeh Ghazvini, M ; Kharrat, R ; Masihi, M ; Sharif University of Technology
    In force gas/oil gravity drainage process in fractured porous media, gas is flowing in both matrix and fractures leading to produce a finite gas pressure gradient. Consequently, viscous force plays an important role for displacing matrix oil toward fractures in addition to gravity force that is required to be modeled appropriately. A new analytical model for estimation of steady state oil saturation distribution with assumption of fixed gas pressure gradient throughout the matrix is presented. Moreover, based on some results of this analytical model a different numerical formulation is developed to predict the performance of oil production process. Comparison of the results obtained from... 

    Numerical modeling of density-driven solute transport in fractured porous media with the extended finite element method

    , Article Advances in Water Resources ; Volume 136 , 2020 Hosseini, N ; Bajalan, Z ; Khoei, A. R ; Sharif University of Technology
    Elsevier Ltd  2020
    In this paper, a numerical model is developed based on the X-FEM technique to simulate the transport of dense solute in a single fluid phase through the fractured porous media. The governing equation is based on the mass conservation law which is applied to the fluid phase and the solute in both matrix and fracture domain. The integral governing equations of the mass exchange between the fracture and the surrounding matrix is derived. The extended finite element method (X-FEM) is applied by employing appropriate enrichment functions to model the fractured porous domain. The superiority of the X-FEM is that the FE mesh is not necessary to be conformed to the fracture geometry, so the regular... 

    Static and dynamic evaluation of the effect of nanomaterials on the performance of a novel synthesized PPG for water shut-off and improved oil recovery in fractured reservoirs

    , Article Journal of Petroleum Science and Engineering ; Volume 189 , June , 2020 Khoshkar, P. A ; Fatemi, M ; Ghazanfari, M. H ; Sharif University of Technology
    Elsevier B. V  2020
    Among different methods which are introduced to reduce unwanted water production, “Preformed Particle Gel” (PPG) is a recently developed type of these gels that can have important advantages such as temperature resistance and long-term stability. The aim of the present work is to synthesize a new type of PPG in which the above specifications are improved even further with the advantage of the Nano-material (here after called N-PPG) and then investigate its effectiveness via static bulk tests as well as dynamic Hele-Shaw and Micromodel tests. In static tube tests, the swelling performance of N-PPG samples was evaluated under different conditions. The examined parameters include various pH of... 

    Convective-reactive transport of dissolved CO2 in fractured-geological formations

    , Article International Journal of Greenhouse Gas Control ; Volume 109 , 2021 ; 17505836 (ISSN) Shafabakhsh, P ; Ataie Ashtiani, B ; Simmons, C. T ; Younes, A ; Fahs, M ; Sharif University of Technology
    Elsevier Ltd  2021
    Carbon dioxide (CO2) storage in geologic formations is an attractive means of reducing greenhouse gas emissions. The main processes controlling the migration of CO2 in geological formations are related to convective mixing and geochemical reactions. The effects of heterogeneity on these coupled processes have been widely discussed in the literature. Recently, special attention has been devoted to fractured geological formations that can be found in several storage reservoirs. However, existing studies on the effect of fractures on the fate of CO2 neglect the key processes of geochemical reactions. This work aims at addressing this gap. Based on numerical simulations of a hypothetical... 

    A physically-based three dimensional fracture network modeling technique

    , Article Scientia Iranica ; Volume 19, Issue 3 , 2012 , Pages 594-604 ; 10263098 (ISSN) Masihi, M ; Sobhani, M ; Al Ajmi, A. M ; Al Wahaibi, Y. M ; Khamis Al Wahaibi, T ; Sharif University of Technology
    In poorly developed fractured rocks, the contribution of individual fracture on rock conductivity should be considered. However, due to the lack of data, a deterministic approach cannot be used. The conventional way to model discrete fractures is to use a Poisson process, with prescribed distribution, for fracture size and orientation. Recently, a stochastic approach, based on the idea that the elastic energy due to fractures follows a Boltzmann distribution, has been used to generate realizations of correlated fractures in two dimensions. The elastic energy function has been derived by applying the appropriate physical laws in an elastic medium. The resulting energy function has been used... 

    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... 

    Thermo-hydro-mechanical modeling of fracturing porous media with two-phase fluid flow using X-FEM technique

    , Article International Journal for Numerical and Analytical Methods in Geomechanics ; Volume 44, Issue 18 , October , 2020 , Pages 2430-2472 Khoei, A. R ; Mortazavi, S. M. S ; Sharif University of Technology
    John Wiley and Sons Ltd  2020
    In this paper, a fully coupled thermo-hydro-mechanical model is presented for two-phase fluid flow and heat transfer in fractured/fracturing porous media using the extended finite element method. In the fractured porous medium, the traction, heat, and mass transfer between the fracture space and the surrounding media are coupled. The wetting and nonwetting fluid phases are water and gas, which are assumed to be immiscible, and no phase-change is considered. The system of coupled equations consists of the linear momentum balance of solid phase, wetting and nonwetting fluid continuities, and thermal energy conservation. The main variables used to solve the system of equations are solid phase...