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    Experimental and Simulation Study of Asphaltene Deposition in Porous Media

    , M.Sc. Thesis Sharif University of Technology Khalili, Mohammad (Author) ; Ghotbi, sirous (Supervisor) ; Kharrat, Reyaz (Supervisor)
    Abstract
    Asphaltene deposition on reservoir rocks occurs during natural depletion as well as miscible injection processes. It causes reduction of effective pore space and consequent impairment of the ability of oil to flow through reservoir. Therefore, deposition of asphaltene causes significant formation damage and wellbore plugging, requiring expensive and difficult cleanup procedures. Thus it is necessary to be able to consider the onset, amount of deposition and also consequent damage of permeability and porosity reduction due to various factors. The objective of current work is to conduct experimental and simulation study of asphaltene deposition dynamics in one of the Iranian reservoirs. In... 

    Experimental and Theoretical Study of Hydrodynamic Behavior and Mechanisms of Asphaltene Deposition

    , Ph.D. Dissertation Sharif University of Technology Jafari Behbahani, Taraneh (Author) ; Ghotbi, Cyrus (Supervisor) ; Taghikhani, Vahid (Supervisor) ; Shahrabadi, Abbas (Supervisor)
    Abstract
    In this work, a new model based on the multilayer adsorption kinetic mechanism and four material balance equations for oil, asphaltene, gas and water phase has been developed to account asphaltene deposition in porous media under dynamic condition and the model was verified using experimental data obtained in this work and also with those reported in the literature. The results showed that the developed model can correlate more accurately the oil flooding experimental data in comparison to the previous models based on the mechanical plugging mechanism, in particular in carbonate core samples. Also, a series of experiments was carried to determine the permeability reduction of carbonate,... 

    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
    2013
    Abstract
    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... 

    Investigation of asphaltene precipitation in miscible gas injection processes: Experimental study and modeling

    , Article Brazilian Journal of Chemical Engineering ; Volume 29, Issue 3 , 2012 , Pages 665-676 ; 01046632 (ISSN) Moradi, S ; Dabiri, M ; Dabir, B ; Rashtchian, D ; Emadi, M. A ; Sharif University of Technology
    2012
    Abstract
    Asphaltene precipitation during natural depletion and miscible gas injection is a common problem in oilfields throughout the world. In this work, static precipitation tests are conducted to investigate the effects of pressure, temperature and gas type and concentration on asphaltene instability. Three different oil samples have been studied under reservoir conditions with/without nitrogen and methane injection. Besides applying common thermodynamic models, a new scaling equation is presented to predict asphaltene precipitation under HPHT gas injection. Extensive published data from the literature are also used in model development. The scaling approach is attractive because it is simple and... 

    Effect of miscible nitrogen injection on instability, particle size distribution, and fractal structure of asphaltene aggregates

    , Article Journal of Dispersion Science and Technology ; Volume 33, Issue 5 , 2012 , Pages 763-770 ; 01932691 (ISSN) Moradi, S ; Dabir, B ; Rashtchian, D ; Mahmoudi, B ; Sharif University of Technology
    Abstract
    Precipitation, aggregation, and breakup of asphaltene particles are studied under natural depletion and nitrogen injection processes by means of high pressure filtration and a photographic procedure coupled with image analysis. Filtration results show that nitrogen destabilizes asphaltenes extremely, and the problem is more severe for heavier crude samples. Bimodal histograms of particle size distribution show two agglomeration mechanisms: cluster aggregation dominant around bubble point pressure and diffusion limited far away. The fractal structure of aggregates is also altered by gas injection; it is observed that the flocculent masses grow in size and become more compact and organized... 

    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
    2012
    Abstract
    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.... 

    A study on possible injection of greenhouse gases CO2 in order to enhanced oil recovery and economic assessment

    , 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 5341-5345 ; 9781629937908 (ISBN) Fatahi Mehraban, L ; Masihi, M ; Fatahi Mehraban, M ; Sharif University of Technology
    European Association of Geoscientists and Engineers, EAGE  2012
    Abstract
    This paper summarizes the possibility of carbon dioxide gas Injection and compares the results with natural depletion in one of Iranian under saturated oil reservoir. At first with using PVTi software and Eclipse simulator, slim tube test has been simulated and Minimum Miscibility Pressure (MMP) of carbon dioxide gas with reservoir fluid determined then simulation of CO2 injection had done and at the end assessment of economic conditions for CO2 injection had been considered. Results had shown CO2 is an optimized choice for gas injection in this oil reservoir  

    Comprehensive study of asphaltene precipitation due to gas injection: Experimental investigation and modeling

    , Article Society of Petroleum Engineers - SPE Enhanced Oil Recovery Conference 2011, EORC 2011, 19 July 2011 through 21 July 2011 ; Volume 1 , July , 2011 , Pages 208-219 ; 9781618390929 (ISBN) Zadeh, G. A. R ; Moradi, S ; Dabir, B ; Emadi, M. A ; Rashtchian, D ; Sharif University of Technology
    2011
    Abstract
    Asphaltene precipitation during natural depletion and miscible gas injection is a common problem in oilfields throughout the world. In this work, static precipitation tests are conducted to investigate effect of pressure, temperature and gas type and concentration on asphaltene instability. Three different oil samples are studied under reservoir conditions with/without nitrogen and methane injection. Besides applying common thermodynamic models, a new scaling equation is presented to predict asphaltene precipitation under HPHT gas injection. Published data from literature are also used in model development. The scaling approach is attractive because it is simple and complex asphaltene... 

    Experimental investigation of the asphaltene deposition process during different production schemes

    , Article Oil and Gas Science and Technology ; Volume 66, Issue 3 , 2011 , Pages 507-519 ; 12944475 (ISSN) Bagheri, M. B ; Kharrat, R ; Ghotby, C ; Sharif University of Technology
    2011
    Abstract
    Experimental Investigation of the Asphaltene Deposition Process during Different Production Schemes - This paper presents the results of asphaltene precipitation and deposition during lean gas injection, CO2 injection and natural depletion in reservoir conditions. In addition, the effect of variations in operating pressure, injection gas concentration and production rate on asphaltene precipitation and deposition were investigated. The severity of asphaltene deposition was found to be more pronounced in lean gas injection in comparison with CO2 injection and natural depletion. Increasing the flow rate in natural depletion xperiments showed a considerable increase in asphaltene deposition,... 

    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
    Abstract
    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... 

    Asphaltene deposition under dynamic conditions in porous media: Theoretical and experimental investigation

    , Article Energy and Fuels ; Volume 27, Issue 2 , 2013 , Pages 622-639 ; 08870624 (ISSN) Jafari Behbahani, T ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
    2013
    Abstract
    In this work, a new model based on the multilayer adsorption kinetic mechanism and four material balance equations for oil, asphaltene, gas, and water phase has been developed to account for asphaltene deposition in porous media under dynamic conditions and the model was verified using experimental data obtained in this work and also with those reported in the literature. The results showed that the developed model based on multilayer adsorption kinetic mechanism can correlate more accurately the oil flooding experimental data in comparison to the previous models based on the mechanical plugging mechanism, in particular in carbonate core samples. Also, a series of experiments was carried to...