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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
    Abstract
    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... 

    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
    2013
    Abstract
    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
    Abstract
    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  

    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
    2010
    Abstract
    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... 

    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
    Abstract
    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... 

    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
    Abstract
    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
    Abstract
    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,... 

    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
    2008
    Abstract
    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... 

    Study and Development of Dual Porosity/Permeability Models for Simulation of Forced Gravity Drainage Mechanism in Fractured Porous Media

    , M.Sc. Thesis Sharif University of Technology Samimi Ardestani, Ehsan (Author) ; Massihi, Mohsen (Supervisor) ; Gerami, Shahab (Supervisor) ; Ganjeh Ghazvini, Mostafa (Co-Advisor)
    Abstract
    The available investigations show that gravity drainage mechanism in fractured reservoir make a high recovery factor in comparison with other mechanisms. In recent years, the forced gravity drainage assisted by gas injection is also introduced; despite of its importance there is no comprehensive modeling study in the literature. The fractured reservoir is simulated frequently by dual porosity models in which the transfer function is the key issue for this method of simulation. This study makes an effort by comparison of different transfer functions with fine grid simulation results of a single block model, in order to evaluate their ability for simulation of forced gravity drainage... 

    Experimental and Modeling Study of Gravity Drainage in Multi-Stack Blocks System

    , M.Sc. Thesis Sharif University of Technology Karimi Malekabadi, Farzan (Author) ; Ghazanfari, Mohammad Hossein (Supervisor) ; Rostami, Behzad (Supervisor) ; Gudarznia, Iraj (Supervisor)
    Abstract
    Gravity drainage is known as one of the major mechanisms of oil recovery in naturally fractured reservoirs which petroleum engineers conducted research in this realm. Block to block interaction such as capillary continuity and reinfiltration mainly control the efficiency of this mechanism. In this study, first of all, free fall and forced gravity drainage experiments have been conducted in a single block apparatus and effect of some parameters like, density viscosity relation, matrix permeability, vertical fracture aperture, presence of viscose force and type of injected gas were investigated, in the second step, three stack block apparatus were designed and constructed. This apparatus were... 

    , M.Sc. Thesis Sharif University of Technology Reza Veisi, Mohsen (Author) ; Ghotbi, Siroos (Supervisor) ; Ayatollahi, Shahabedin (Co-Advisor)
    Abstract
    In water drive or waterflooded reservoirs, a significant amount of oil is remained in the reservoir as the residual oil. A process known as gas assisted gravity drainage, in its tertiary mode, has been applied in a number of conventional reservoirs to recover this residual oil. Gravity drainage is the main mechanism of oil recovery in the gas assisted gravity drainage enhanced oil recovery process. Previous investigations has shown that gravity force, spreading coefficient, three phase capillary pressure and reservoir wettability have significant effect on oil recovered via this process. The feasibility of using such a process in a naturally fractured reservoir is investigated in this work... 

    Pore Scale Modeling of Gravity Drainage in Fractured Porous Media

    , M.Sc. Thesis Sharif University of Technology Mehrizadeh, Masoud (Author) ; Ghazanfari, Mohammad Hossein (Supervisor)
    Abstract
    Most of oil content, especially in Iran, has been reserved in fractured reservoirs, so study and modeling of production mechanism of these reservoirs are great of importance. Gravity drainage is one of these effective production mechanisms in fractured porous media which dynamic pore scale modeling of this mechanism will lead to better understanding of it. In this work, the effects of variety of parameters such as oil gravity, interfacial tension between oil and gas, pore and throat size distribution, fracture aperture, and block to block interaction (capillary continuity and reinfiltartion) have been investigated. So developed simulator in this work has two main and separated parts, which... 

    Modeling the Gravity Drainage during Miscible Gas Injection in Fractured Reservoirs

    , M.Sc. Thesis Sharif University of Technology Rezaei, Hojjat (Author) ; Masihi, Mohsen (Supervisor) ; Ghazanfari, Mohammad Hossein (Supervisor)
    Abstract
    The production of oil is challenging in the fractured reservoirs due to the large transmissibility contrast between matrix and fracture, and primary recovery is often low. The recovery efficiency depends on the relationship between the fracture and matrix permeability, and is strongly dependent on the wettability of the matrix, which reflects the imbibition potential of the reservoir. Among these parameters the multiphase fluid flow in gas invaded zone is the point of interest in this project. Gas injection in naturally fractured reservoirs maintains the reservoir pressure, and increases oil recovery primarily by gravity drainage and to a lesser extent by mass transfer between the flowing... 

    Experimental Study and Modeling of Scale up in Multi-blocks Fractured Porous Media

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Mohammad (Author) ; Ghazanfari, Mohammad Hossein (Supervisor) ; Rostami, Behzad (Supervisor)
    Abstract
    Fractured reservoirs constitute a major portion of world’s petroleum reservoirs. Gravity drainage is the controlling production mechanism in these reservoirs. Thus, investigation of performance and oil production in fractured models has been the subject of many researches. Despite the considerable number of experimental and modeling studies in this area, the method of scale-up in single or multi block models is not broadly investigated. This work is divided into two experimental and modeling sections. For the experimental study, free fall gravity drainage experiments in synthetic single or multi block porous media were performed in order to investigate effects of different parameters... 

    The gas-oil gravity drainage model in a single matrix block: A new relationship between relative permeability and capillary pressure functions

    , Article Journal of Porous Media ; Vol. 14, issue. 8 , 2011 , p. 709-720 ; ISSN: 1091028X Dejam, M ; Ghazanfari, M. H ; Kamyab, M ; Masihi, M ; Sharif University of Technology
    Abstract
    This work concerns modeling of gas-oil gravity drainage for a single block of naturally fractured reservoirs. The nonlinearity induced from saturation-dependant capillary pressure and relative permeability functions makes a gravity drainage model difficult to analytically and numerically solve. Relating the capillary pressure and relative permeability functions is a potential method to overcome this problem. However, no attempt has been made in this regard. In this study a generalized one-dimensional form of gas-oil gravity drainage model in a single matrix block, presented in the literature, is considered. In contrast with commonly used forms of capillary pressure and relative permeability... 

    A study of enhanced heavy oil recovery by two well cyclical steam assisted gravity drainage (TWC-SAGD) in conventional and fractured reservoirs

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 10 , Dec , 2014 , pp. 1065-1076 ; ISSN: 15567036 Ghoodjani, E ; Bolouri, S. H ; Sharif University of Technology
    Abstract
    Steam-assisted gravity drainage is one of the most promising strategies to develop huge heavy oil and bitumen accumulations. Like the other thermal processes, this method aims at reducing oil viscosity by increasing the temperature. But in an economical point of view, it requires a great volume of steam for injection. Moreover, early breakthrough of steam and high steam-oil ratio makes it uneconomical, especially in long production time. In this study, a new method, two wells cyclical steam-assisted gravity drainage is compared with a conventional steam-assisted gravity drainage process. Well configuration in two wells cyclical steam-assisted gravity drainage is the same as the... 

    The gas-oil gravity drainage model in a single matrix block: A new relationship between relative permeability and capillary pressure functions

    , Article Journal of Porous Media ; Volume 14, Issue 8 , 2011 , Pages 709-720 ; 1091028X (ISSN) Dejam, M ; Ghazanfari, M. H ; Kamyab, M ; Masihi, M ; Sharif University of Technology
    2011
    Abstract
    This work concerns modeling of gas-oil gravity drainage for a single block of naturally fractured reservoirs. The nonlinearity induced from saturation-dependant capillary pressure and relative permeability functions makes a gravity drainage model difficult to analytically and numerically solve. Relating the capillary pressure and relative permeability functions is a potential method to overcome this problem. However, no attempt has been made in this regard. In this study a generalized one-dimensional form of gas-oil gravity drainage model in a single matrix block, presented in the literature, is considered. In contrast with commonly used forms of capillary pressure and relative permeability... 

    A fully implicit single phase T-H-M fracture model for modelling hydraulic fracturing in oil sands

    , Article Journal of Canadian Petroleum Technology ; Volume 43, Issue 6 , 2004 , Pages 35-44 ; 00219487 (ISSN) Pak, A ; Chan, D. H ; Sharif University of Technology
    Society of Petroleum Engineers (SPE)  2004
    Abstract
    Enhancing oil extraction from oil sands with a hydraulic fracturing technique has been widely used in practice. Due to the complexity of the actual process, modelling of hydraulic fracturing is far behind its application. Reproducing the effects of high pore pressure and high temperature, combined with, complex stress changes in the oil sand reservoir, requires a comprehensive numerical model which is capable of simulating the fracturing phenomenon. To capture all of these aspects in the problem, three partial differential equations, i.e., equilibrium, flow, and heat transfer, should be solved simultaneously in a fully implicit (coupled) manner. A fully coupled thermo-hydro-mechanical... 

    Experimental investigation of secondary and tertiary oil recovery from fractured porous media

    , Article Journal of Petroleum Exploration and Production Technology ; Volume 3, Issue 3 , September , 2013 , Pages 179-188 ; 21900558 (ISSN) Maroufi, P ; Ayatollahi, S ; Rahmanifard, H ; Jahanmiri, A ; Riazi, M ; Sharif University of Technology
    2013
    Abstract
    Naturally fractured reservoirs (NFRs) contribute in large extent to oil and gas production to the ever increasing market demand of fossil energy. It is believed that the vertical displacement of oil during gas injection assisted by gravity drainage (GAGD) is one of the most efficient methods for oil recovery in these reservoirs. Hence, in this work, unconsolidated packed models of cylindrical geometry surrounded by fracture were utilized in order to perform a series of flow visualization experiments during which the contribution of different parameters such as the extent of matrix permeability, physical properties of oil (viscosity, density, and surface tension) and the withdrawal rate was... 

    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
    2011
    Abstract
    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...