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Numerical Investigation of Different Ventilation Systems in Coal Mines Effects on the Fire Extinguishing
, M.Sc. Thesis Sharif University of Technology ; Afshin, Hossein (Supervisor) ; Farhanieh, Bijan (Co-Supervisor)
Abstract
In recent years, due to fires in mines around the world, the need to study the dynamic behavior of fire to understand how it spreads and design an appropriate fire extinguishing system to reduce damage to people and underground facilities has been felt. Mine fires are usually caused by external sources such as cable connections, methane gas explosions, or coal self-ignition due to oxygen uptake and rising temperatures.In this research, using Fire Dynamic Simulator (FDS) software, after drawing the geometry of a coal tunnel corridor in progress and creating a fire model through pyrolysis of PVC, fire extinguishing was performed by nozzles. If the nozzle does not succeed in extinguishing the...
Experimental Investigation of the Effect of Pressure and Gas Composition on the Interfacial Behavior of Gas/Oil System under High Pressure High Temperature Conditions
, M.Sc. Thesis Sharif University of Technology ; Fatemi, Mobeen (Supervisor) ; Ghazanfari, Mohammad Hossein (Co-Supervisor)
Abstract
Gas injection process is one of the main methods to increase the hydrocarbon reservoirs. Minimum Miscibility pressure is a key parameter that controls the efficiency of the gas injection process. It depends on the temperature, the composition of the injected gas and the composition of the reservoir fluids. In this study, the interfacial tension of the live oil-gas system of one of the reservoirs of southwestern Iran was obtained by analyzing the Pendant drop method at 225 ° F and different pressures, and then by using the Vanishing Interfacial Tension method, the Minimum Miscibility Pressure has been computed .In this study, pure and base gases such as nitrogen, methane and injection gas of...
Experimental determination of equilibrium interfacial tension for nitrogen-crude oil during the gas injection process: The role of temperature, pressure, and composition
, Article Journal of Chemical and Engineering Data ; Vol. 59, issue. 11 , September , 2014 , p. 3461-3469 ; ISSN: 00219568 ; Ayatollahi, S ; Zolghadr, A ; Ghazanfari, M. H ; Masihi, M ; Sharif University of Technology
Abstract
Nitrogen has emerged as a competitive gas injection alternative for gas-based enhanced oil recovery processes in the past two decades. The injection of nitrogen into the reservoirs has improved the oil recovery efficiency in various oil reservoirs from heavy to volatile oils. As it is known, interfacial tension (IFT) plays a key role in any enhanced oil recovery process, particularly gas injection processes; therefore, its accurate determination is crucial for the design of any gas injection process especially at reservoir condition. In this study, an axisymmetric drop shape analysis (ADSA) was utilized to measure the equilibrium IFTs between crude oil and N2 at different temperature levels...
Prediction of asphaltene precipitation during solvent/CO2 injection conditions: A comparative study on thermodynamic micellization model with a different characterization approach and solid model
, Article Journal of Canadian Petroleum Technology ; Vol. 50, issue. 3 , March , 2011 , p. 65-74 ; Masihi, M ; Ghazanfari, M. H ; Kharrat, R ; Sharif University of Technology
Abstract
There are different thermodynamic models that have been applied for modelling of asphaltene precipitation caused by various reasons, such as solvent/CO2 injection and pressure depletion. In this work, two computer codes based on two different asphaltene precipitation thermodynamic models-the first being the thermodynamic micellization model with a different characterization approach and the second being the solid model-have been developed and used for predicting asphaltene precipitation data reported in the literature as well as in the obtained data for Sarvak reservoir crude, which is one of the most potentially problematic Iranian heavy oil reserves under gas injection conditions. For the...
Prediction of asphaltene precipitation during pressure depletion and CO2 injection for heavy crude
, Article Petroleum Science and Technology ; Vol. 28, issue. 9 , Mar , 2009 , p. 892-902 ; ISSN: 10916466 ; Kharrat, R ; Masihi, M ; Ghazanfari, M. , H ; Sharif University of Technology
Abstract
In this work, a thermodynamic approach is used for modeling the phase behavior of asphaltene precipitation. The precipitated asphaltene phase is represented by an improved solid model, and the oil and gas phases are modeled with an equation of state. The Peng-Robinson equation of state (PR-EOS) was used to perform flash calculations. Then, the onset point and the amount of precipitated asphaltene were predicted. A computer code based on the solid model was developed and used for predicting asphaltene precipitation data reported in the literature as well as the experimental data obtained from high-pressure, high-temperature asphaltene precipitation experiments performed on Sarvak reservoir...
A numerical comparative study of various flooding techniques in hydrocarbon reservoirs
, Article Journal of Porous Media ; Volume 15, Issue 2 , 2012 , Pages 101-112 ; 1091028X (ISSN) ; Manzari, M. T ; Hannani, S. K ; Sharif University of Technology
2012
Abstract
This paper investigates the efficiency and performance of several of the fiooding techniques popular in secondary and enhanced oil recovery. These processes include water fiooding, immiscible and miscible gas fiooding, and several forms of water-alternating-gas (WAG) injection. The study is carried out numerically on a typical one-dimensional domain using an advanced high-resolution central scheme. Some performance indices such as oil cut drop, breakthrough time, and sweep efficiency were employed to evaluate the appropriateness of each injection strategy
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) ; 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...
Asphaltene deposition during CO 2 injection and pressure depletion: A visual study
, Article Energy and Fuels ; Volume 26, Issue 2 , December , 2012 , Pages 1412-1419 ; 08870624 (ISSN) ; Ayatollahi, S ; Alamdari, A ; Zolghadr, A ; Dashti, H ; Kord, S ; Sharif University of Technology
Abstract
Carbon dioxide miscible flooding has become a popular method for Enhanced Oil Recovery (EOR) because it not only efficiently enhances oil recovery but also considerably reduces green house gas emissions. However, it can significantly cause asphaltene deposition, which leads to serious production problems such as wettability alteration, plugging of the reservoir formation, blocking the transportation pipelines, etc. It is crucial to investigate the effects of different factors on asphaltene deposition. A novel experimental setup was prepared to employ a high-pressure visual cell for investigation of asphaltene deposition on a model rock under typical reservoir conditions. The evolution of...
Experimental investigation of CO2 WAG injection to light crude oil in near miscible conditions
, 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 ; 2012 , Pages 3914-3918 ; 9781629937908 (ISBN) ; Ghazanfari, M. H ; Masihi, M ; Sharif University of Technology
European Association of Geoscientists and Engineers, EAGE
2012
Abstract
This work concerns with experimental investigation of CO2 WAG injection to light crude oil in near miscible conditions which has been rarely attended in the available literature. Here, several core flood experiments at three constant injection rates and four WAG ratios are conducted on sandstone rocks saturated with light crude oil in presence of saline water. The results showed that higher injection rate has a better performance regarding oil recovery for smaller PVs of injected fluids, while lower injection rate showed higher ultimate recovery for a 30% increase in injected PVs. Secondary continuous gas injection showed a superior performance than all the other WAG injections in different...
Optimal conditions for immiscible recycle gas injection process: A simulation study for one of the Iranian oil reservoirs
, Article Scientia Iranica ; Volume 18, Issue 6 , 2011 , Pages 1407-1414 ; 10263098 (ISSN) ; Kharrat, R ; Khalili, M ; Mehranfar, M ; Sharif University of Technology
2011
Abstract
Immiscible gas injection is one of the most common enhanced oil recovery methods used under various reservoir conditions. In this work, the immiscible recycle gas injection, as an EOR scenario for improving recovery efficiency in one of the south-west Iranian oil reservoirs, is simulated by a commercial simulator, ECLIPSE. The reservoir fluid is light oil, with an API of 43. The oil bearing formations are carbonate, and so a dual porosity/dual permeability behavior was chosen for better representation of the fracture system. Different sensitivity analyses with respect to several parameters like the number and location of injection/production wells, production/injection rate, completion...
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) ; 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,...
Prediction of asphaltene precipitation during solvent/CO2 injection conditions: A comparative study on thermodynamic micellization model with a different characterization approach and solid model
, Article Journal of Canadian Petroleum Technology ; Volume 50, Issue 3 , 2011 , Pages 65-74 ; 00219487 (ISSN) ; Masihi, M ; Ghazanfari, M. H ; Kharrat, R ; Sharif University of Technology
Abstract
There are different thermodynamic models that have been applied for modelling of asphaltene precipitation caused by various reasons, such as solvent/CO2 injection and pressure depletion. In this work, two computer codes based on two different asphaltene precipitation thermodynamic models-the first being the thermodynamic micellization model with a different characterization approach and the second being the solid model-have been developed and used for predicting asphaltene precipitation data reported in the literature as well as in the obtained data for Sarvak reservoir crude, which is one of the most potentially problematic Iranian heavy oil reserves under gas injection conditions. For the...
Prediction of asphaltene precipitation during pressure depletion and CO2 injection for heavy crude
, Article Petroleum Science and Technology ; Volume 28, Issue 9 , Apr , 2010 , Pages 892-902 ; 10916466 (ISSN) ; Kharrat, R ; Masihi, M ; Ghazanfari, M. H ; Sharif University of Technology
2010
Abstract
In this work, a thermodynamic approach is used for modeling the phase behavior of asphaltene precipitation. The precipitated asphaltene phase is represented by an improved solid model, and the oil and gas phases are modeled with an equation of state. The Peng-Robinson equation of state (PR-EOS) was used to perform flash calculations. Then, the onset point and the amount of precipitated asphaltene were predicted. A computer code based on the solid model was developed and used for predicting asphaltene precipitation data reported in the literature as well as the experimental data obtained from high-pressure, high-temperature asphaltene precipitation experiments performed on Sarvak reservoir...
An improvement on modeling of forced gravity drainage in dual porosity simulations using a new matrix-fracture transfer function
, Article Transport in Porous Media ; Volume 94, Issue 1 , 2012 , Pages 207-223 ; 01693913 (ISSN) ; Masihi, M ; Gerami, S ; Ghazvini, M. G ; Sharif University of Technology
Abstract
In fractured oil reservoirs, the gravity drainage mechanism has great potentials to higher oil recovery in comparison with other mechanisms. Recently, the forced gravity drainage assisted by gas injection has also been considered; however, there are few comprehensive studies in the literature. Dual porosity model, the most common approach for simulation of fractured reservoirs, uses transfer function concept to represent the fluid exchange between matrix and its neighborhood fractures. This study compares the results of different available transfer functions with those of fine grid simulations when forced gravity drainage contributes to oil production from a single matrix block. These...
An improvement of thermodynamic micellization model for prediction of asphaltene precipitation during gas injection in heavy crude
, Article Fluid Phase Equilibria ; Volume 308, Issue 1-2 , September , 2011 , Pages 153-163 ; 03783812 (ISSN) ; Masihi, M ; Ghazanfari, M. H ; Kharrat, R ; Sharif University of Technology
Abstract
Thermodynamic micellization model is known as an appropriate approach for prediction of asphaltene precipitation. However, the reliability (i.e. accuracy) of this model for whole range of pressure or injected gas mole percent must be checked. In practice, the accuracy can be improved by using a suitable characterization method. In this research, a computer code for implementing the thermodynamic micellization model has been developed. Having used this program, we make the prediction of asphaltene precipitation by using data reported in the literature as well as the experimental data obtained from high pressure, high temperature asphaltene precipitation experiments under gas injection...
Application of population balance equation in modeling of asphaltene particle size distribution and characterization of aggregation mechanisms under miscible gas Injection
, Article Journal of Molecular Liquids ; Volume 232 , 2017 , Pages 207-213 ; 01677322 (ISSN) ; Hamed Mahvelati, E ; Ameli, F ; Dabir, B ; Rashtchian, D ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Particle size distribution (PSD) is an important factor that determines how asphaltene instability can damage porous media during natural depletion and enhanced oil recovery processes. In this work, aggregate size distribution under natural depletion and miscible nitrogen injection processes are determined via image analysis techniques and the results are modelled by population balance equation. Unimodal distribution curves in natural depletion show the dominance of particle-particle aggregation mechanism and the clustering is detected only around crude oil bubble point pressure. It is also observed that miscible nitrogen injection considerably increases the number and size of asphaltene...
Water film rupture in blocked oil recovery by gas injection: experimental and modeling study
, Article Chemical Engineering Science ; Volume 161 , 2017 , Pages 288-298 ; 00092509 (ISSN) ; Rostami, B ; Ghazanfari, M. H ; Khosravi, M ; Sharif University of Technology
Abstract
Water shielding phenomenon generally occurs after waterflooding in water-wet rocks, and impedes direct contact between the oil and the injected gas in tertiary gas injection processes. In this work, a set of visualization experiments were performed on micromodel patterns including designed dead-end pores with a film of water on the surface of pore bodies, which is a more realistic representation of porous media. The experiments were conducted at different miscibility conditions, and the required time for water to be displaced from the throat by the swelling of oil was measured for first contact miscible (n-C5/CO2) and immiscible (n-C10/CO2) systems. In the next step, a model was proposed to...
Modeling interfacial tension of normal alkane-supercritical CO2 systems: Application to gas injection processes
, Article Fuel ; Volume 253 , 2019 , Pages 1436-1445 ; 00162361 (ISSN) ; Hemmati Sarapardeh, A ; Tatar, A ; Zanganeh, A ; Ayatollahi, S ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
To study the gas injection scenario for successful implementation of enhanced oil recovery (EOR)processes, the prediction of interfacial tension (IFT)between injected gas and the crude oil is of paramount significance. In the present study, some intelligent methods were developed for determining IFT values between supercritical CO2 and normal alkanes. IFT was considered as a function of temperature, pressure, and molecular weight of normal alkanes. The developed methods were Multilayer perceptron (MLP), Genetic Algorithm Radial Basis Function (GA-RBF), and Conjugate Hybrid-PSO ANFIS (CHPSO-ANFIS). The average absolute percent relative errors (AAREs)for the stated techniques were found to be...
Application of particle swarm optimization and genetic algorithm for optimization of a southern Iranian oilfield
, Article Journal of Petroleum Exploration and Production ; Volume 11, Issue 4 , 2021 , Pages 1781-1796 ; 21900558 (ISSN) ; Dehghan, A ; Yousefzadeh, R ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
Optimization of the placement and operational conditions of oil wells plays an important role in the development of the oilfields. Several automatic optimization algorithms have been used by different authors in recent years. However, different optimizers give different results depending on the nature of the problem. In the current study, a comparison between the genetic algorithm and particle swarm optimization algorithms was made to optimize the operational conditions of the injection and production wells and also to optimize the location of the injection wells in a southern Iranian oilfield. The current study was carried out with the principal purpose of evaluating and comparing the...
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) ; 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...