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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... 

    Modeling of asphaltene deposition during miscible CO2 Flooding

    , Article Petroleum Science and Technology ; Vol. 32, Issue. 18 , 2014 , Pages 2183-2194 ; ISSN: 10916466 Tahami, S. A ; Dabir, B ; Asghari, K ; Shahvaranfard, A ; Sharif University of Technology
    Abstract
    The authors present the results of numerical tests and simulations to investigate and analyze the likelihood of asphaltene precipitation and deposition during CO2 flooding in a reservoir. The effects of asphaltene precipitation on oil properties such as oil viscosity and density during miscible CO2 flooding process were elaborated by using Winprop software of Computer Modeling Group. Also oil properties change during CO 2 miscible flooding by numerical slim tube were investigated by a compositional simulator (GEM). A fluid sample of Saskatchewan Reservoir that had been flooded miscibly with CO2 was chosen for performing the sensitivity analyses. The results showed that asphaltene... 

    Analysis of Capillary-Viscous-Gravity Forces in Biopolymer Flooding with a Sensitivity Analysis on Polymer and Porous Medium Parameters

    , Article Journal of Dispersion Science and Technology ; Vol. 35, issue. 12 , Aug , 2014 , p. 1764-1773 Hamidpour, E ; Mirzaei-Paiaman, A ; Ramazani, S. A. A ; Hatami, A ; Sharif University of Technology
    Abstract
    Gravity, viscous, and capillary are three main forces affecting flow characteristics in porous media. No analytical solution can be found to model the flow by considering all these forces. In this work, by considering all these forces, the polymer-flooding process is modeled by using a numerical simulation approach. For characterizing the polymer, the modified Blake-Kozeny model is chosen, which benefits consideration of the permeability reduction due to polymer adsorption on the rock surface  

    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
    2013
    Abstract
    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... 

    A newmodel for permeability reduction rate due to calciumsulfate precipitation in sandstone cores

    , Article Journal of Porous Media ; Volume 13, Issue 10 , 2010 , Pages 911-922 ; 1091028X (ISSN) Tahmasebi, H. A ; Soltanieh, M ; Kharrat, R ; Sharif University of Technology
    2010
    Abstract
    In this work, a reliable dimensionless correlation is proposed for prediction of permeability reduction rate in porous media, which is verified by experimental data obtained in this work in glass bead and sand pack as well as the core data from the literature. Although this correlation is based on the data which were obtained in our work in glass bead and sand-packed media at low pressure, it shows considerable flexibility to match with the extracted data for sandstone cores at high pressure, various flow rates, different temperatures and concentrations of calcium, and sulfate ions in brine solutions. In addition, a novel relationship for predicting the rate of precipitation of CaSO4 in... 

    Dimensionless correlation for the prediction of permeability reduction rate due to calcium sulphate scale deposition in carbonate grain packed column

    , Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 41, Issue 3 , 2010 , Pages 268-278 ; 18761070 (ISSN) Tahmasebi, H. A ; Kharrat, R ; Soltanieh, M ; Sharif University of Technology
    Abstract
    In this work, an experimental and theoretical study has been conducted to investigate the permeability reduction due to CaSO4 scale deposition in packed column porous media. Permeability reduction by calcium sulphate deposition follows a systematic trend considering various important parameters that are affected in this complex process. Hence, a novel dimensionless model has been proposed for the prediction of permeability reduction rate with high accuracy. The developed model is based on the data obtained from glass bead and carbonate grain packed column at low pressure. The proposed model was validated with Berea sandstone cores data at high pressure (100-20,678 kPa), various flow rates... 

    Modeling Aphron-Based Drillng Fluid Penetration Rate into the Reservoir Formation and Analyzing the Permeability Change Behavior

    , M.Sc. Thesis Sharif University of Technology Rahimi, Mohammad Amin (Author) ; Jamshidi, Saeed (Supervisor)
    Abstract
    Aphron drilling fluids or CGA fluids are the wellknown updated drilling fluids in recent years.this kind of drilling fluids can control the mud loss into the formation and thus reduce formation damage and drilling costs. its structure consists of two phase fluid (gas and liquid) that the aphrons are the micro bubbles with 10 to 100 micrometer diameter that have strong stability in liquid phase compared to foamy drilling fluids. Generally aphron drilling fluids are made of base drilling fluid and surfactants, for more stability, mixed surfactant-polymer additive is so beneficial. in the last two decades, the Lattice-Boltazmann method is introduced for computational fluid dynamic area and... 

    Modeling and Experimental Study of Gas Reservoir Formation Damage Caused by Solid-based Drilling Fluids

    , M.Sc. Thesis Sharif University of Technology Vasheghani Farahani, Mehrdad (Author) ; Jamshidi, Saeed (Supervisor)
    Abstract
    Nowadays, one of the most challenges in drilling and production engineering, is the formation damage caused by fluid filtration while drilling and completion operations. This damage would cause serious problems in pay zone and besides influencing the well performance during its life time – due to permeability reduction in near wellbore area- and cause economic expenses such as workover and stimulation operation. Therefore, considering the aspects of formation damage minimization during drilling and completion operations, the fluid selection for these purposes would be crucial. It requires the knowledge of interactions between these fluids and the reservoir rock. In this thesis, using the... 

    Investigation of asphaltene adsorption in sandstone core sample during CO2 injection: Experimental and modified modeling

    , Article Fuel ; Vol. 133 , 2014 , Pages 63-72 ; ISSN: 00162361 Jafari Behbahani, T ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
    Abstract
    In this work, asphaltene adsorption in a sandstone core sample under dynamic conditions and during miscible CO2 injection was studied using live oil sample which is close to real conditions in petroleum reservoirs. In order to investigate of damage in sandstone core sample by the deposited material such as asphaltene, the morphology analysis of sandstone core sample using scanning electron microscopic method was studied. Also analyses of the adsorbed material in sandstone core sample by Soxhlet extraction using an azeotrope mixture and with SARA method were performed. The experimental results show that by increasing the flow rate of injected CO2, the amount of asphaltene in retained material... 

    A core scale investigation of Asphaltene precipitation during simultaneous injection of oil and CO2: An experimental and simulation study

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 10 , Dec , 2014 , pp. 1077-1092 ; ISSN: 15567036 Bagherzadeh, H ; Rashtchian, D ; Ghazanfari, M. H ; Kharrat, R ; Sharif University of Technology
    Abstract
    Although CO2 injection significantly increases the amount of oil recovered, it can cause asphaltene deposition in oil reservoirs. Asphaltene deposition leads to formation damage, in which treatment is a costly and problematic operation. In this work, impact of asphaltene precipitation and deposition during CO2 injection are investigated for recombined oil both in sandstone and carbonate core samples through dynamic flow experiments. Injection of oil and CO2 was performed simultaneously. Then, pressure drops along the core were recorded continuously to estimate permeability reductions during the experiments. Online viscosity of injected fluid was measured by a designed capillary viscometer.... 

    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
    2012
    Abstract
    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... 

    Permeability reduction of membranes during particulate suspension flow; analytical micro model of size exclusion mechanism

    , Article Journal of Membrane Science ; Vol. 435, issue , May , 2013 , p. 155-164 ; ISSN: 3767388 Bashtani, F ; Ayatollahi, S ; Habibi, A ; Masihi, M ; Sharif University of Technology
    Abstract
    Particle capture at porous media in cross-flow microfiltration is studied to investigate permeability reduction as a function of membrane pore size and particle size distribution. A new model in pore scale and its pertinent mathematical expressions, which consider pore and particle size distribution, are provided. Permeability reduction of the membrane because of size exclusion during particulate suspension flow was predicted using the developed model. It is assumed that the size exclusion is the dominant mechanism of particle retention causes pore blocking and permeability reduction in the porous media.The exact analytical solution of the stochastic model for size exclusion is used to... 

    Permeability reduction of membranes during particulate suspension flow; analytical micro model of size exclusion mechanism

    , Article Journal of Membrane Science ; Volume 435 , 2013 , Pages 155-164 ; 03767388 (ISSN) Bashtani, F ; Ayatollahi, S ; Habibi, A ; Masihi, M ; Sharif University of Technology
    2013
    Abstract
    Particle capture at porous media in cross-flow microfiltration is studied to investigate permeability reduction as a function of membrane pore size and particle size distribution. A new model in pore scale and its pertinent mathematical expressions, which consider pore and particle size distribution, are provided. Permeability reduction of the membrane because of size exclusion during particulate suspension flow was predicted using the developed model. It is assumed that the size exclusion is the dominant mechanism of particle retention causes pore blocking and permeability reduction in the porous media.The exact analytical solution of the stochastic model for size exclusion is used to... 

    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... 

    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.... 

    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,... 

    Experimental study and mathematical modeling of asphaltene deposition mechanism in core samples

    , Article Oil and Gas Science and Technology ; Volume 70, Issue 6 , Nov , 2015 , Pages 1051-1074 ; 12944475 (ISSN) Jafari Behbahani, T ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
    Editions Technip  2015
    Abstract
    In this work, experimental studies were conducted to determine the effect of asphaltene deposition on the permeability reduction and porosity reduction of carbonate, sandstone and dolomite rock samples using an Iranian bottom hole live oil sample which is close to reservoir conditions, whereas in the majority of previous work, a mixture of recombined oil (a mixture of dead oil and associated gas) was injected into a core sample which is far from reservoir conditions. The effect of the oil injection rate on asphaltene deposition and permeability reduction was studied. The experimental results showed that an increase in the oil injection flow rate can result in an increase in asphaltene... 

    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
    2010
    Abstract
    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... 

    Pore-scale insights into sludge formation damage during acid stimulation and its underlying mechanisms

    , Article Journal of Petroleum Science and Engineering ; Volume 196 , 2021 ; 09204105 (ISSN) Mirkhoshhal, S. M ; Mahani, H ; Ayatollahi, S ; Mohammadzadeh Shirazi, M ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    Acid-oil emulsion and sludge formation are known as two major formation damage mechanisms and the reason for failure of some acid treatments. The published studies in this area focus primarily on core- to well/reservoir-scale and it is fairly unclear how acid-oil interaction at the pore-scale leads to the formation damage observed at the macro- or core-scale. In this paper, dynamic, micro-scale experiments were designed and executed to investigate the acid-induced formation damage using microfluidic approach. In addition, a series of so-called static (microscope) tests were performed in which acid-crude oil compatibility tests were conducted on a glass slide followed by microscopic... 

    Investigation on asphaltene deposition mechanisms during CO2 flooding processes in porous media: A novel experimental study and a modified model based on multilayer theory for asphaltene adsorption

    , Article Energy and Fuels ; Volume 26, Issue 8 , 2012 , Pages 5080-5091 ; 08870624 (ISSN) Jafari Behbahani, T ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
    2012
    Abstract
    In this paper, oil recovery and permeability reduction of a tight sandstone core sample in miscible CO2 flooding processes due to asphaltene deposition were studied using an Iranian bottom hole live oil sample in order to distinguish between the mechanical plugging and adsorption mechanisms of asphaltene involved in the interfacial interaction of the asphaltene/mineral rock system. A novel experimental method was designed and proposed to measure the amount of deposited asphaltene due to different mechanisms using the cyclohexane or toluene reverse flooding and spectrophotometer. In this work, the bottom hole live oil sample was injected first to a long core and then CO 2 injection was...