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    Asphaltene deposition in carbonate rocks: Experimental investigation and numerical simulation

    , Article Energy and Fuels ; Volume 26, Issue 10 , June , 2012 , Pages 6186-6199 ; 08870624 (ISSN) Kord, S ; Miri, R ; Ayatollahi, S ; Escrochi, M ; Sharif University of Technology
    Oil production from asphaltenic oil reservoirs has always encountered difficulties, such as plugging and unpredictable fluid properties. To physically recognize the aspects of asphaltene deposition, several dynamic and static asphaltene deposition tests were designed and performed on one of the giant south Iranian oil reservoirs using dead and live crude oil and real core samples. Moreover, the effects of fluid velocity on the extent of damage were investigated. It was found that surface deposition of asphaltene particles is the main source of formation damages in the porous media and the resulting permeability impairment obeys an exponential behavior. All of the experiments confirm that... 

    Modeling formation damage due to asphaltene deposition in the porous media

    , Article Energy and Fuels ; Volume 25, Issue 2 , February , 2011 , Pages 753-761 ; 08870624 (ISSN) Soulgani, B. S ; Tohidi, B ; Jamialahmadi, M ; Rashtchian, D ; Sharif University of Technology
    Asphaltene deposition in a reservoir severely reduces the effective permeability and results in a reduction in oil production. The main term in asphaltene deposition modeling in the porous media is pore surface deposition. Previous models do not describe the effects of different parameters (i.e., concentration, velocity, and temperature) on the pore surface deposition term. We report the results of a series of experiments carried out to study the effects of the above parameters on the surface deposition term using an accurate thermal method. Based on these data, a new expression for the surface deposition term has been developed and implemented in asphaltene deposition modeling. The... 

    An experimental investigation of permeability impairment under dynamic flow conditions due to natural depletion in an Iranian oilfield

    , Article Petroleum Science and Technology ; Volume 31, Issue 3 , 2013 , Pages 250-261 ; 10916466 (ISSN) Khalifeh, M ; Bagherzadeh, H ; Bolouri, H ; Sharif University of Technology
    Asphaltene deposition is an issue that has received much attention since it has been shown to be the cause of major production problems. It leads to permeability reduction under the processes of natural depletion as well as hydrocarbon gas/CO2 injection. Though a great deal of researches have focused on studying permeability impairment in reservoir rocks, little is known about the asphaltene deposition mechanisms that control the permeability reduction for Iranian reservoirs. In this work, an experimental effort is made to investigate the permeability impairment of core samples of Iranian oil reservoirs. The experiments are performed on both sandstone and carbonate rock types at reservoir... 

    Optimization assisted asphaltene deposition modeling in porous media during a natural depletion scheme

    , Article Petroleum Science and Technology ; Volume 30, Issue 9 , Mar , 2012 , Pages 958-965 ; 10916466 (ISSN) Hematfar, V ; Bagheri, M ; Kharrat, R ; Ghazanfari, M ; Ghotbi, C ; Sharif University of Technology
    Changes in thermodynamic properties such as pressure, temperature, and composition may result in asphaltene precipitation and deposition in porous media. In addition, asphaltene deposition can cause wettability alteration, permeability reduction, and ultimately a decrease in the productivity of a reservoir. Natural depletion is one of the most common processes of asphaltene deposition in which pressure changes destabilize the dissolved asphaltene in the oil and settle them onto the rock surface. In this work, natural depletion experiments in consolidated core samples were performed under simulated reservoir conditions to obtain reliable data and analyze the asphaltene deposition mechanisms.... 

    Investigation of asphaltene deposition mechanisms during primary depletion and CO2 injection

    , Article Society of Petroleum Engineers - 9th European Formation Damage Conference 2011, 7 June 2011 through 10 June 2011 ; Volume 1 , June , 2011 , Pages 223-231 ; 9781617829673 (ISBN) Jafari Behbahani, T ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
    Asphaltene deposition causes serious problems in the oil industry. Variation of oil composition and reservoir pressure is reported to be the most important factors that influence asphaltene deposition from reservoir oil. In this study, a mathematical model was developed to simulate asphaltene deposition during primary depletion and CO2 injection. The main purpose of this study is to investigate and to compare asphaltene deposition mechanisms due to primary depletion and CO2 injection. The solid model as thermodynamic model was applied to investigate asphaltene precipitation. A numerical model was established to the governing equations both in space and time and model parameters were... 

    Modeling and optimization of asphaltene deposition in porous media using genetic algorithm technique

    , Article Society of Petroleum Engineers - International Oil and Gas Conference and Exhibition in China 2010, IOGCEC, 8 June 2010 through 10 June 2010 ; Volume 1 , June , 2010 , Pages 479-491 ; 9781617388866 (ISBN) Hematfar, V ; Kharrat, R ; Ghazanfari, M. H ; Bagheri, M. B ; Sharif University of Technology
    Different models have been proposed for deposition of asphaltene on reservoir rocks that due to complexity of asphaltene nature, most of them have not been productive. Here, a reliable model is proposed which despite of previous models, considers the change in asphaltene saturation in the core. The obtained experimental data in the laboratory was used for model validation. In this work, a series of core flooding tests was carried out in presence of connate water at different solvent-oil volume ratios. Pressure drop was measured at three different terminals along the core. The obtained experimental data as well as mass balance equations, momentum equation, asphaltene deposition and... 

    Dynamic modeling and optimization of asphaltene deposition in reservoir rocks using genetic algorithm

    , Article 72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 ; Volume 6 , 2010 , Pages 4291-4295 ; 9781617386671 (ISBN) Bagheri, M. B ; Kharrat, R ; Hemmatfar, V ; Ghotbi, C ; Sharif University of Technology
    Society of Petroleum Engineers  2010
    Asphaltene deposition is a problematic challenge for oil production. Changes in key parameters like pressure and fluid composition during natural depletion and different gas injection scenarios may result in asphaltene precipitation and deposition. In this work, a model is developed by application of mass balance equations, momentum equation, asphaltene deposition and permeability reduction models. An algorithm is developed to perform iterative procedure to solve the numerical equations that contains highly coupled variables. Indeed, an equation is introduced to calculate the saturation of the precipitated asphaltene phase. Model parameters were determined by genetic algorithm which is a...