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molecular-diffusion-coefficient
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Experimental Investigation of Molecular Diffusion Coefficients of Gas-Oil for the Iranian Oil Field Fluids
, M.Sc. Thesis Sharif University of Technology ; Kazemeini, Mohammad (Supervisor) ; Kharat, Reyaz (Supervisor) ; Ghazanfari, Mohammad Hossein (Co-Advisor)
Abstract
Molecular diffusion of gases in crude oils plays a crucial role in several oil recovery processes especially in cold-based production process. Nowadays, heavy oil is a considerable part of the world hydrocarbon reservoirs and its importance increases as the ordinary oil reserves decrease. The main obstacle in heavy oil production is its low mobility (i.e. high viscosity). This difficulty can be easily solved by injecting gas solvent in these reservoirs. However, experimental data concerning CO2 diffusivity in heavy oils due to the tedious nature of diffusivity measurements are relatively rare in the open literature. In this work, a comprehensive experimental investigation of the effective...
Experimental Study for Determining the Diffusion Coefficient of Nitrogen and Methane Gases in Crude Oil
, M.Sc. Thesis Sharif University of Technology ; Ghazanfari, Mohammad Hossein (Supervisor)
Abstract
Gas injection is one of the common methods for enhance oil recovery from oil reservoirs. At miscible injection condition, the efficiency of the process is majorly affected by the molecular diffusion coefficient of the gas in the oil. Therefore, the accurate value of this coefficient is an essential for applying in reservoir simulator. However, determination of this coefficient only is possible through experimental methods. In this study, pressure decay method was applied to determine the diffusion coefficient of nitrogen, methane and carbon dioxide gases in crude oil. The reasons for choosing this method are : accuracy in designing the experiment, covering a wide range of pressure...
The determination of effective diffusivity coefficients in a solvent gas heavy oil system for methane
, Article Petroleum Science and Technology ; Volume 30, Issue 24 , 2012 , Pages 2582-2593 ; 10916466 (ISSN) ; Dadvar, M ; Kharrat, R ; Ghazanfari, M. H ; Sharif University of Technology
2012
Abstract
In this investigation, an accurate high pressure and temperature diffusion setup was applied to measure the diffusion coefficients of methane in Iranian heavy oils in presence and absence of porous media by using the pressure-decay method. The solvent diffusivity in heavy oil was determined by both graphical and numerical methods. In addition, the effects of the porous medium and the temperature on the molecular diffusion coefficient of the solvent gas in the liquid phase were discussed and finally, using experimental data, a functionality dependence of molecular diffusivity on temperature and porous medium characteristics was proposed
Experimental investigation of gas-heavy oil molecular diffusion coefficient in porous media: Experimental results for CO2 in Iranian Crudes
, Article Defect and Diffusion Forum ; Volume 312-315 , 2011 , Pages 1049-1054 ; 10120386 (ISSN) ; 9783037851173 (ISBN) ; Kazemeini, M ; Kharrat, R ; Ghazanfari, M. H ; Salehi, A ; Sharif University of Technology
Abstract
Molecular diffusion of gases in crude oils plays a crucial role in several oil recovery processes especially in cold-based production process. However, experimental data concerning CO2 diffusivity in heavy oils due to the tedious nature of diffusivity measurements are relatively rare in the open literature. In this work, a comprehensive experimental investigation of the effective molecular diffusion determination of CO2-heavy oil systems in homogeneous porous media was studied. The so-called pressure decay method was applied to measure the molecular diffusivity of carbon dioxide in heavy oil. Furthermore, effect of various parameters such as initial pressure, temperature and porous media on...
Prediction of CO2-oil molecular diffusion using adaptive neuro-fuzzy inference system and particle swarm optimization technique
, Article Fuel ; Volume 181 , 2016 , Pages 178-187 ; 00162361 (ISSN) ; Sahebi, H ; Ghiasi, M. M ; Mirjordavi, N ; Esmaeilzadeh, F ; Lee, M ; Bahadori, A ; Sharif University of Technology
Elsevier Ltd
Abstract
The quantification of carbon dioxide (CO2) dissolution in oil is crucial in predicting the potential and long-term behavior of CO2 in reservoir during secondary and tertiary oil recovery. Accurate predicting carbon dioxide molecular diffusion coefficient is a key parameter during carbon dioxide injection into oil reservoirs. In this study a new model based on adaptive neuro-fuzzy inference systems (ANFIS) is designed and developed for accurate prediction of carbon dioxide diffusivity in oils at elevated temperature and pressures. Particle Swarm Optimization (PSO) as population based stochastic search algorithms was applied to obtain the optimal ANFIS model parameters. Furthermore, a simple...