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    Screening of Thermodynamic Models in Predicting Phase Behavior of Asphaltenic Crudes Applicable in Dynamic Deposition Models

    , M.Sc. Thesis Sharif University of Technology Naghdi Nasab, Mohammad Ali (Author) ; Taghikhani, Vahid (Supervisor)
    Abstract
    Prediction and prevention from asphaltene deposition is an essential topic in oil production systems that can enormously increase oil production costs. Many studies have been done to understand and predict the behavior of asphaltene-containing oils. Prediction and investigation of asphaltene precipitation are required to predict the asphaltene deposition problem. Changes in temperature, pressure, and composition can cause precipitation, and these changes are inevitable during production. This dissertation compares the thermodynamic models that can simulate asphaltene precipitation. Firstly, A comprehensive review was done to extract the maximum amount of experimental data from the literature... 

    Experimental investigation and modeling of asphaltene precipitation due to Gas Injection

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 31, Issue 1 , 2012 , Pages 89-98 ; 10219986 (ISSN) Moradi, S ; Rashtchian, D ; Ganjeh Ghazvini, M ; Emadi, M. A ; Dabir, B ; Sharif University of Technology
    2012
    Abstract
    Asphaltene instability is one of the major problems in gas injection projects throughout the world. Numerous models have been developed to predict asphaltene precipitation; The scaling equation is an attractive tool because of its simplicity and not involving complex properties of asphaltene. In this work, a new scaling model is presented to account for asphaltene precipitation due to gas injection at reservoir conditions. Extensive published data from literature have been used in model preparation. To check predictive capability of the equation, miscible gas injection experiments are conducted for a southwest Iranian oil reservoir. Experimental results show that methane injection has... 

    A novel method for mitigation of asphaltene deposition in the wellstring

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 29, Issue 2 , 2010 , Pages 131-142 ; 10219986 (ISSN) Soltani Soulgani, B ; Rashtchian, D ; Tohidi, B ; Jamialahmadi, M ; Sharif University of Technology
    2010
    Abstract
    Asphaltene precipitation and deposition is a serious problem in many Iranian fields. The deposited asphaltene results in partial or total blockage of the wellbore and wellstring reducing or completely seizing oil production. This paper studies the asphaltene problem and mitigation methods in wellstring systematically. It presents new approach based on the combination of thermodynamic modeling of asphaltene precipitation with hydrodynamic well modeling. The developed model is capable to determine the asphaltene precipitation and deposition interval through the wellstring. Therefore, it could study the effect of hydrodynamic parameters such as wellhead pressure, well flow-rate and tubing size... 

    Experimental and modelling investigations of asphaltene precipitation during pressure depletion and gas injection operations

    , Article Petroleum Science and Technology ; Vol. 32, issue. 15 , August , 2014 , pp. 1868-1875 ; ISSN: 10916466 Nakhli, H ; Alizadeh, A ; Afshari, S ; Kharrat, R ; Ghazanfari, M ; Sharif University of Technology
    Abstract
    Asphaltene precipitation problems manifest themselves in different stages of oil reservoirs production. Experimental and modeling investigations are, therefore, employed as promising tools to assist in predictions of asphaltene precipitation problems and selection of proper production facilities. This study concerns experimental and modeling investigations of asphaltene precipitation during natural production and gas injection operations for a heavy Iranian crude oil at reservoir conditions. First, with design and performance of high pressure-high temperature experiments, asphaltene precipitation behavior is comprehensively investigated; the effects of pressure and temperature are fully... 

    Experimental study of asphaltene precipitation behavior during miscible carbon dioxide injection

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 14 , July , 2014 , pp. 1523-1530 ; ISSN: 15567036 Alizadeh, A ; Nakhli, H ; Kharrat, R ; Ghazanfari, M. H ; Aghajani, M ; Sharif University of Technology
    Abstract
    Many reservoir and production engineers face asphaltene precipitation as a major problem during miscible carbon dioxide flooding projects. Experimental studies regarding asphaltene precipitation are therefore employed to assist in selecting appropriate facilities and proper operation schemes. During this study, a series of high pressure, high temperature experiments are designed and performed to analyze asphaltene precipitation behavior of an Iranian light reservoir crude at reservoir conditions due to natural production and miscible CO2 gas injection. For both sets of experiments, two different temperature levels (including reservoir temperature) are selected to investigate the role of... 

    Application of ANFIS-GA algorithm for forecasting oil flocculated asphaltene weight percentage in different operation conditions

    , Article Petroleum Science and Technology ; Volume 36, Issue 12 , 2018 , Pages 862-868 ; 10916466 (ISSN) Keybondorian, E ; Soltani Soulgani, B ; Bemani, A ; Sharif University of Technology
    Taylor and Francis Inc  2018
    Abstract
    Asphaltene which cover range of 1% to over 10% of oil by weight, is well-known as most problematic part of oil that can deposit during production in reservoir, well tubing, and surface production lines, and consequently impose a serious restriction on production which in turn increases total cost of entire operation. Through decades an extensive research has been performed in order to identify asphaltene molecular structure, its behavior at different condition, and its separation mechanism from oil. One of most critical parameter associated with asphaltene precipitation modeling is flocculated asphaltene weight percentage in oil at given operation condition. In this study, to eliminate cost... 

    Phase behavior modeling of asphaltene precipitation for heavy crude including the effect of pressure and temperature

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 19 , Feb , 2014 , p. 2087-2094 ; ISSN: 15567036 Tavakkoli, M ; Ghazanfari, M. H ; Masihi, M ; Kharrat, R ; Sharif University of Technology
    Abstract
    Despite numerous experimental and modeling studies, the role of temperature changes on phase behavior modeling of asphaltene precipitation and, in consequence, developing of asphaltene phase envelope in heavy crudes, remains a topic of debate in the literature. In this work, a computer code based on the non-isothermal improved solid model has been developed and used for predicting asphaltene precipitation data for one of the Iranian heavy crudes at different levels of temperature and pressure. The parameters of the non-isothermal model were tuned using three onset pressures at three different temperatures, and the asphaltene phase envelope was developed. The results showed that at high... 

    Asphaltene deposition in different depositing environments: Part 2. Real oil

    , Article Energy and Fuels ; Vol. 28, Issue. 6 , 2014 , Pages 3594-3603 ; ISSN: 08870624 Tavakkoli, M ; Panuganti, S. R ; Taghikhani, V ; Pishvaie, M. R ; Chapman, W. G ; Sharif University of Technology
    Abstract
    This paper is a continuation of our previous paper (part 1; 10.1021/ef401857t), which discussed the roles of different phenomena effecting the deposition of asphaltene from model oil systems and before the onset of asphaltene precipitation. The study in this paper is to understand the depositional tendency of asphaltene using a quartz crystal microbalance with dissipation (QCM-D) measurements and their corresponding modeling for real crude oil systems with emphasis after the onset of asphaltene precipitation  

    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... 

    Investigating the Effects of Different Parameters on Asphaltene Deposition Using Electrodeposition Technique

    , M.Sc. Thesis Sharif University of Technology Hosseini, Ali (Author) ; Ayatollahi, Shahabeddin (Supervisor) ; Taghikhani, Vahid (Supervisor)
    Abstract
    Additional to Temperature, Pressure and Compositional changes of crude oils, Electro-kinetics and Electrical potential effects are also known as the most influencing parameters on Asphaltene deposition during oil production and processing.Mechanisms of electro-kinetics and asphaltene charge generation are very complex and unclear. In the previous studies on asphaltene precipitation and deposition, mostly electro-kinetics effects are ignored.While, recent studies show the great effects of electrical filed on asphaltene deposition during production and processing phase of crude oils.At reservoir porous medium and crude flow line, an electrical field can be developed along the length of the... 

    Development of a Simulator to Simulate Multi-phase Flow with Asphaltene Precipitation in the Wellbore

    , M.Sc. Thesis Sharif University of Technology Hassanpour Youzband, Aliakbar (Author) ; Taghikhani, Vahid (Supervisor) ; Bozorgmehri, Ramin (Supervisor)
    Abstract
    Asphaltene, the heaviest and most polarizable fraction of crude oil, has a potential to precipitate, deposit and plug pipelines, causing considerable production costs. The main objective of this study is to contribute to the thermodynamic and transport modeling of asphaltene in order to predict its precipitation, segregation and deposition. Potential calculation of some thermophysical properties of asphaltene is also explored. Predicting the flow assurance issues caused by asphaltene requires the ability to model the phase behavior of asphaltene as a function of pressure, temperature and composition. It has been previously demonstrated that the Perturbed Chain form of Statistical Association... 

    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... 

    Asphaltene deposition in different depositing environments: Part 1. model oil

    , Article Energy and Fuels ; Vol. 28, Issue. 3 , 2014 , pp. 1617-1628 ; ISSN: 08870624 Tavakkoli, M ; Panuganti, S. R ; Vargas, F. M ; Taghikhani, V ; Pishvaie, M. R ; Chapman, W. G ; Sharif University of Technology
    Abstract
    Among the asphaltene flow assurance issues, the most major concern because of asphaltene is its potential to deposit in reservoir, well tubing, flow lines, separators, and other systems along production lines causing significant production losses. Hence, the focus of this study is to understand the depositional tendency of asphaltene using quartz crystal microbalance with dissipation (QCM-D) measurements. The results are presented in two consecutive papers, with this paper (part 1) dealing with model oil systems. The depositing environment is varied by changing the system temperature, asphaltene polydispersity, solvent (asphaltene stability), depositing surface, and flow rate. This paper... 

    A modified scaling equation based on properties of bottom hole live oil for asphaltene precipitation estimation under pressure depletion and gas injection conditions

    , Article Fluid Phase Equilibria ; Volume 358 , 2013 , Pages 212-219 ; 03783812 (ISSN) Jafari Behbahani, T ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
    2013
    Abstract
    The process of asphaltene precipitation has a substantial effect on oil flow during primary oil production and enhanced oil recovery processes in the petroleum industry. In this work, a modified scaling model based on the PVT properties of bottom hole live oil including resin to asphaltene ratio, onset pressure, bubble point pressure, reservoir temperature, asphaltene content of bottom hole live oil and gas to oil ratio has been proposed to account for asphaltene precipitation under pressure depletion/gas injection conditions and the proposed model was verified using experimental data obtained in this work and also with those reported in the literature. In the proposed scaling model the... 

    The gas-oil interfacial behavior during gas injection into an asphaltenic oil reservoir

    , Article Journal of Chemical and Engineering Data ; Volume 58, Issue 9 , 2013 , Pages 2513-2526 ; 00219568 (ISSN) Escrochi, M ; Mehranbod, N ; Ayatollahi, S ; Sharif University of Technology
    2013
    Abstract
    Oil displacement and recovery efficiency during gas injection depends on the competition between driving forces and capillary resistance that is governed by gas-oil interfacial behavior. Detailed study of the interfacial forces during gas injection is the main objective of this research work. The effects of injecting gas composition and the possibility of asphaltene precipitation in a wide pressure range were determined through comprehensive experimental study. This was performed by measurement of interfacial tension of a highly asphaltenic Iranian crude oil in three surrounding gas mediums. The results showed that as pressure increases, the rate to reach miscibility reduces in the vicinity... 

    Modeling of asphaltene precipitation in calculation of minimum miscibility pressure

    , Article Industrial and Engineering Chemistry Research ; Volume 56, Issue 25 , 2017 , Pages 7375-7383 ; 08885885 (ISSN) Kariman Moghaddam, A ; Saeedi Dehaghani, A. H ; Sharif University of Technology
    American Chemical Society  2017
    Abstract
    An algorithm has been developed to investigate the effect of asphaltene precipitation on calculation of minimum miscibility pressure (MMP), which is one of the key design parameters of any gas injection projects. In fact, this algorithm is the extension of procedure suggested by Jaubert et al. for prediction of MMP whatever the displacement mechanism. The vapor-liquid equilibrium calculation and then liquid-liquid equilibrium calculation are required to be taken account to estimate the amount of asphaltene precipitation. The association equation of state (AEOS) has been applied to determine the phase behavior of asphaltene. The algorithm has been used for the MMP prediction of Weyburn... 

    Thermodynamic Modeling of Asphaltene Precipitation for One of Iranian Oil Reservoirs

    , M.Sc. Thesis Sharif University of Technology Tavakkoli, Mohammad (Author) ; Kharrat, Riyaz (Supervisor) ; Masihi, Mohsen (Supervisor)
    Abstract
    Thermodynamic modeling is a useful method for predicting of asphaltene precipitation due to various reasons, such as CO2 injection, mixing of different oils in oil storage and pressure changes. However, the application of solid model and thermodynamic micellization model, for prediction of asphaltene precipitation under gas injection condition, hasnot been improved. In this work, two computer codes which are based on two different asphaltene precipitation thermodynamic models, 1-Thermodynamic Micellization Model and 2- Solid Model, have been developed, and, used for predicting of asphaltene precipitation data reported in the literature as well as the experimental data obtained from high... 

    Effect of Nitrogen Injection on Phase Behavior and Asphaltene Instability

    , Ph.D. Dissertation Sharif University of Technology Moradi, Siyamak (Author) ; Rashtchian, Davood (Supervisor) ; Dabir, Bahram (Supervisor) ; Emadi, Mohammad Ali (Supervisor)
    Abstract
    Nitrogen injection is a promising enhanced oil recovery process. Asphaltene precipitation during miscible gas injection is a common problem in oilfields throughout the world. In this work, a comprehensive study is conducted on effect of gas injection on phase behavior and asphaltene instability of live oil samples. Effects of oil API, gas type and concentration, pressure and temperature 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 more compared to methane and the problem is more severe for heavier crude samples.... 

    Modeling of Asphaltene Deposition in Flow Lines Considering Pressure and Temperature Drop

    , M.Sc. Thesis Sharif University of Technology Eyni, Leila (Author) ; Ayatollahi, Shahabeddin (Supervisor) ; Assareh, Mehdi (Supervisor)
    Abstract
    Crude oil is made up of dozens of chemicals which based on their structural similarity, SARA test separate it into four categories: saturates, aromatics, resins and asphaltene. Asphaltenes are recognized as the largest, heaviest and the most polarizable fraction of the crude oil which are in thermodynamic equilibrium with oil at reservoir conditions. Each of the physical, chemical, electrical or mechanical disruption of this balance during production can result in instability and asphaltene precipitation may occur and eventually led to deposition in the reservoir, wells, pipelines, etc. Due to the fact that most changes in temperature and pressure will generated in the wells, thus... 

    Experimental and Simulation Study of Formation Damage Due to Asphaltene Precipitation under CO2 Injection Condition in One of Iranian Carbonate Oil Reservoirs

    , M.Sc. Thesis Sharif University of Technology Bagherzadeh, Hadi (Author) ; Rashtchian, Davoud (Supervisor)
    Abstract
    Asphaltenedeposition is a major problem during natural depletion and EOR processes due to formation damage issues. It is necessary to reveal asphaltene deposition mechanisms and its effective parameters to prepare an acceptable prevention strategy. Therefore, different natural depletion and EOR experiments must performed on core samples. In this research, Effect of CO2 injection on asphaltene deposition phenomena has been surveyed. Two carbonate core samples and one sandstone core sample was used in experiments. The oil used in these experiments was recombinedoilfrom one of Iranian offshore oilfield.In order to estimate permeability reduction during experiment, injection of oil and CO2 was...