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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... 

    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... 

    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  

    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... 

    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... 

    Experimental investigation of asphaltene-induced core damage during miscible CO2 injection

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 13 , 2014 , pp. 1395-1405 ; ISSN: 15567036 Bolouri, H ; Ghoodjani, E ; Sharif University of Technology
    Abstract
    In this article, dynamic core flood experiments in miscible CO2 condition were carried out to investigate core damage due to asphaltene deposition. Carbonate and sandstone cores were used to study of effect of core characteristic on permeability and porosity reduction. The experimental results show asphaltene deposition preferentially in sandstone core type takes place in the first half of the core while in the carbonate one it occurs in the second half. In spite of asphaltene content measurement results (IP-143) that show higher asphaltene deposition in sandstone cores, permeability impairment compared to the carbonate one is severe. Also, permeability-porosity reduction models are affected... 

    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... 

    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... 

    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... 

    Reversibility of Asphaltene Aggregation in Live Oils: Qualitative and Quantitative Evaluation

    , Article Journal of Chemical and Engineering Data ; Volume 60, Issue 9 , August , 2015 , Pages 2646-2654 ; 00219568 (ISSN) Mohammadi, S ; Rashidi, F ; Mousavi Dehghani, S. A ; Ghazanfari, M. H ; Sharif University of Technology
    American Chemical Society  2015
    Abstract
    Despite the numerous experimental studies concerning asphaltene, the extent of reversibility of asphaltene aggregation at reservoir conditions remains still an elusive and controversial issue in the available literature. In this work, a series of depressurization and repressurization experiments were performed on three different live oils for qualitative and quantitative evaluation of the reversibility of asphaltene aggregation under typical pressure and temperature conditions of oil fields. The obtained results reveal that the kinetics and the extent of reversibility of asphaltene aggregation at elevated pressure and temperature are majorly controlled by the characteristics of the reservoir... 

    SAFT model for upstream asphaltene applications

    , Article Fluid Phase Equilibria ; Volume 359 , December , 2013 , Pages 2-16 ; 03783812 (ISSN) Panuganti, S. R ; Tavakkoli, M ; Vargas, F. M ; Gonzalez, D. L ; Chapman, W. G ; Sharif University of Technology
    2013
    Abstract
    The increasing incidence of flow assurance problems caused by asphaltene deposition during oil production has motivated the development of numerous theoretical models and experimental methods to analyze this complex phenomenon. Even more challenging are the prediction of the occurrence and the magnitude of asphaltene deposition. It is well accepted that precipitation of asphaltene is a necessary condition for deposition. Hence, a significant amount of work has been devoted to the understanding of the conditions at which asphaltene precipitate from the crude oil. Although, several models seem to work well for correlating available data of onsets of asphaltene precipitation, they usually lack... 

    On the effect of temperature on precipitation and aggregation of asphaltenes in light live oils

    , Article Canadian Journal of Chemical Engineering ; Volume 94, Issue 9 , 2016 , Pages 1820-1829 ; 00084034 (ISSN) Mohammadi, S ; Rashidi, F ; Mousavi Dehghani, S. A ; Ghazanfari, M. H ; Sharif University of Technology
    Wiley-Liss Inc 
    Abstract
    Asphaltene precipitation and deposition is a serious issue in all facets of petroleum production and processing. Despite the numerous experimental efforts concerning asphaltenes, the effect of temperature on asphaltene precipitation and aggregation in live oils remains an elusive and controversial subject in the available literature. In this work, a series of high pressure-high temperature depressurization experiments were designed to assess the effect of temperature on asphaltene precipitation and aggregation in light live oils. Asphaltene related experiments were performed using a high pressure microscope and high pressure-high temperature filtration setup on a light live oil with a low... 

    Comparison of the effect of temperature on asphaltene destabilisation in light and heavy live oils

    , Article International Journal of Oil, Gas and Coal Technology ; Volume 16, Issue 4 , 2017 , Pages 342-362 ; 17533317 (ISSN) Mohammadi, S ; Rashidi, F ; Mousavi Dehghani, S. A ; Ghazanfari, M. H ; Sharif University of Technology
    Abstract
    The main objective of this study is to investigate the effect of temperature on asphaltene destabilisation (precipitation/aggregation) in live oils at elevated pressure conditions. Here, the asphaltene related experiments were performed using solid detection systems, high pressure microscope, and high pressure-high temperature filtration apparatuses in two Iranian light and heavy live oils with different characteristics and stability. The obtained results were interpreted in terms of asphaltene onset pressure, size distribution and average diameter of the aggregates, fractal analysis of the aggregates structures, and the amount of asphaltene precipitation. As well, the results of the... 

    New two-dimensional particle-scale model to simulate asphaltene deposition in wellbores and pipelines

    , Article Energy and Fuels ; Volume 32, Issue 3 , 2018 , Pages 2661-2672 ; 08870624 (ISSN) Hassanpouryouzband, A ; Joonaki, E ; Taghikhani, V ; Bozorgmehry Boozarjomehry, R ; Chapoy, A ; Tohidi, B ; Sharif University of Technology
    American Chemical Society  2018
    Abstract
    A new two-dimensional dynamic model was developed to simulate asphaltene precipitation, aggregation, and deposition at isothermal and non-isothermal conditions. The perturbed-chain statistical associating fluid theory equation of state was used to model the asphaltene precipitation. Also, novel kinetic models were used to account for the aggregation and deposition of asphaltene particles. The effect of the aggregate size on the rate of aggregation and deposition was studied, and it was concluded that the rate of asphaltene deposition increases, while the concentration of nanoaggregates increases in the well column. The tendency of smaller aggregates to deposit on the surface could be... 

    Simulation study of the Gachsaran asphaltene behavior within the interface of oil/water emulsion: a case study

    , Article Colloids and Interface Science Communications ; Volume 33 , 2019 ; 22150382 (ISSN) Saeedi Dehaghani, A. H ; Soodbakhsh Taleghani, M ; Badizad, M. H ; Daneshfar, R ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    Molecular dynamics (MD) simulation was utilized to study the role of asphaltene extracted from Gachsaran (an Iranian oilfield) at the synthetic oil-water interface. In agreement with experimental data, IFTs predicted by MD simulation for heptol/brine system showed a minima at around 50 vol.% n-heptane, reflecting the highest contribution of asphaltene into the interface. At greater n-heptane fractions, IFT was increased steadily. Simulation results suggest the asphaltene propensity for remaining in the bulk heptol phase rather related to the fraction of toluene in the mixture. Heptol ingredients, i.e., toluene and heptane, act differently with respect to asphaltene, where former tends to... 

    Mechanistic study to investigate the effects of different gas injection scenarios on the rate of asphaltene deposition: An experimental approach

    , Article Fuel ; Volume 262 , 2020 Dashti, H ; Zanganeh, P ; Kord, S ; Ayatollahi, S ; Amiri, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Asphaltene deposition during enhanced oil recovery (EOR) processes is one of the most problematic challenges in the petroleum industry, potentially resulting in flow blockage. Our understanding of the deposition mechanism with emphasis on the rate of the asphaltene deposition is still in its infancy and must be developed through a range of experiments and modelling studies. This study aims to investigate the rate of asphaltene deposition through a visual study under different gas injection scenarios. To visualise the asphaltene deposition, a high-pressure setup was designed and constructed, which enables us to record high-quality images of the deposition process over time. Present research... 

    A modified method for detection of interface and onset point in the asphaltenic fluids

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 Shabani, A ; Bayat Shahparast, M ; Barzegar, F ; Sharif University of Technology
    Taylor and Francis Inc  2020
    Abstract
    Asphaltene precipitation and deposition causes many serious problems to the petroleum industry from the reservoir to the surface facilities. Therefore, it is important to bring it under control by finding a method to accelerate or slow down its precipitation and deposition. For achieving this purpose two parameters play an important role; onset point of the precipitation and amount of the deposited phase. When asphaltene precipitates, it is capable of depositing in the solution. After the deposition, the solution split into two phases; asphaltene-rich and asphaltene-lean. Determining the amount of the deposited phase needs to distinguish the interface between two phases. In this study, a... 

    Effects of asphaltene, resin and crude oil type on the interfacial tension of crude oil/brine solution

    , Article Fuel ; Volume 223 , July , 2018 , Pages 261-267 ; 00162361 (ISSN) Lashkarbolooki, M ; Ayatollahi, S ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    In recent years, the behavior of crude oil interfacial tension (IFT) as a function of salt concentration have been investigated. The results found in literature are highly controversial, thus the current experimental study aimed to clarify the reasons behind this by developing a methodology based on extracting asphaltene and resin from three different crude oils and performing elemental analysis on them. In addition, the effect of salinity on the IFT of three studied crude oil was compared with the synthetic crude oil consisted of different weight percent (wt%) of asphaltene and resin in toluene. The obtained results revealed that the IFT of crude oil as a function of salinity depended not... 

    A new model based on multilayer kinetic adsorption mechanism for asphaltenes adsorption in porous media during dynamic condition

    , Article Fluid Phase Equilibria ; Vol. 375, issue , 2014 , Pages 236-245 ; ISSN: 03783812 Jafari Behbahani, T ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
    Abstract
    In this work, a new model based on multilayer kinetic adsorption mechanism has been proposed to account asphaltene adsorption 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. In the proposed model two steps are considered for asphaltene adsorption. The first step is taken as adsorption of asphaltenes on the surface of the porous media and the second step is taken as adsorption of asphaltenes on the asphaltenes already adsorbed on the porous media. The Crank-Nicholson method, central difference in space and trapezoidal rule in time, giving second order convergence in time was...