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enhanced-recovery
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Phase behavior and interfacial tension evaluation of a newly designed surfactant on heavy oil displacement efficiency; effects of salinity, wettability, and capillary pressure
, Article Fluid Phase Equilibria ; Vol. 396, issue , June , 2015 , p. 20-27 ; ISSN: 03783812 ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
Abstract
This work aims to discuss the results of wide ranges of laboratory investigations to evaluate the performance of a newly-formulated surfactant for heavy oil reservoirs in order to improve the microscopic sweep efficiency after water flooding processes. In the first part, the specific behavior of the formulated surfactant including its salinity tolerance, interfacial tension, and optimum performance window was determined. Then, the application of surfactant solutions in real sandstone reservoir rocks was assessed for both oil-wet and water-wet cases. Besides, the effect of changing the capillary and viscous forces and interfacial tension on the residual phase saturations were characterized....
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...
Toward mechanistic understanding of heavy crude oil/brine interfacial tension: The roles of salinity, temperature and pressure
, Article Fluid Phase Equilibria ; Vol. 375, issue , August , 2014 , p. 191-200 ; ISSN: 03783812 ; Hemmati-Sarapardeh, A ; Ghazanfari, M. H ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
Abstract
Injecting low salinity brines is regarded as an enhanced oil recovery (EOR) process through IFT reduction. However, the exact mechanism behind this process is an unsettled and complex issue that has not been well understood yet, especially for heavy crude oil system. Besides, limited information is available regarding the key heavy oil/brine interfacial tension (IFT). The present study aims to investigate the sensitivity of dead heavy crude oil/brine IFT to a wide range of properties/conditions and to reveal the underlying physicochemical mechanisms involved in enhanced oil recovery and IFT reduction by low salinity water injection into heavy oil reservoir. IFT was measured as a function of...
Monitoring the effect of discontinuous shales on the surfactant flooding performance in heavy oil reservoirs using 2D glass micromodels
, Article Petroleum Science and Technology ; Vol. 32, issue. 12 , Apr , 2014 , p. 1404-1417 ; ISSN: 10916466 ; Kharrat, R ; Masihi, M ; Ghazanfari, M. H ; Saidian, M ; Sharif University of Technology
Abstract
Although most heavy oil reservoirs contain discontinuous shaly structures, there is a lack of fundamental understanding how the shaly structures affect the oil recovery efficiency, especially during surfactant flooding to heavy oils. Here, an experimental study was conducted to examine the effect of discontinuous shales on performance of surfactant flooding by introducing heterogeneities to represent streaks of shale in five-spot glass micromodels. Results show that oil recovery in presence of shale streak is lower than in its absence. Based on the authors' observations, the presence of flow barriers causes premature breakthrough of injected fluids and also an unstable displacement front. As...
An experimental study of the matrix-fracture interaction during miscible displacement in fractured porous media: A micromodel study
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 3 , Oct , 2010 , p. 259-266 ; ISSN: 15567036 ; Masihi, M ; Ghazanfari, M. H ; Kharrat, R ; Mohammadi, S ; Sharif University of Technology
Abstract
During miscible displacements in fractured porous media, one of the most important factors that plays a significant role in oil production is the matrix-fracture interaction. In this work, a series of hydrocarbon injection experiments have been performed on a fractured glass micromodel that was designed specifically to study matrix-fracture interaction. A high quality image analysis method was used to determine the fluid flow behavior, solvent front movement, and viscous fingering associated with solvent movement in matrix and fractures. Observations showed that in the case of unit viscosity ratio, the injection rate increased the slope of recovery curve and consequently improved the final...
Simultaneous/sequential alkaline-surfactant-polymer flooding in fractured/non-fractured carbonate reservoirs
, Article Canadian Journal of Chemical Engineering ; Vol. 92, issue. 5 , May , 2014 , p. 918-927 ; ISSN: 00084034 ; Ghazanfari, M. H ; Masihi, M ; Sharif University of Technology
Abstract
Alkaline-Surfactant-Polymer flooding is one of the most novel chemical enhanced oil recovery methods in the petroleum industry. This method has attracted interest due to its remarkable advantages. In this work, a series of ASP floods are conducted on fractured/non-fractured carbonate rocks. The performance of the tests was investigated by various ASP floods consisting of five types of polymers, two surfactants and one common alkaline. ASP was flooded simultaneously and sequentially in four defined scenarios after water flooding. The results showed that although using hydrolysed polymers increases the recovery factor in the fractured medium, sulfonated polymers increase oil recovery even more...
Evaluation of chemicals interaction with heavy crude oil through water/oil emulsion and interfacial tension study
, Article Energy and Fuels ; Vol. 27, issue. 10 , September , 2013 , p. 5852-5860 ; ISSN: 08870624 ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
Abstract
A newly-designed surfactant was formulated to tolerate the harsh conditions of oil reservoirs, including high salinity of the formation brine and temperature. The specific emulsion and interfacial tension (IFT) behavior of this new surface active agent were investigated by performing emulsion stability tests, emulsion size analysis, and IFT behavior in the presence of four different types of alkalis. Image processing was utilized to analyze the droplet size distribution using microscopic images of the samples. The results show that depending on the composition of the mixtures, the optimum phase region and interfacial tension behavior change considerably. Solutions containing a higher...
Scaling equations for oil/gas recovery from fractured porous media by counter-current spontaneous imbibition: From development to application
, Article Energy and Fuels ; Vol. 27, issue. 8 , July , 2013 , p. 4662-4676 ; ISSN: 08870624 ; Masihi, M ; Sharif University of Technology
Abstract
Spontaneous imbibition, the capillary-driven process of displacing the nonwetting phase by the wetting phase in porous media, is of great importance in oil/gas recovery from matrix blocks of fractured reservoirs. The question of how properly scaling up the recovery by counter-current spontaneous imbibition has been the subject of extensive research over decades, and numerous scaling equations have been proposed. As a convention, the scaling equations are usually defined analytically by relating the early time squared recovery to squared pore volume. We show this convention does not apply to common scaling practices and, if used, causes nontrivial scatter in the scaling plots. We explain that...
Monitoring the role of fracture geometrical characteristics on fingering initiation/development during heavy oil miscible displacements in fractured porous media
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 35, issue. 12 , Aug , 2010 , p. 1129-1139 ; ISSN: 15567036 ; Ghazanfari, M. H ; Masihi, M ; Kharrat, R ; Sharif University of Technology
Abstract
Finger initiation/development at fluid-fluid interface during miscible floods can cause poor displacement efficiency, which is undesirable in enhanced oil recovery processes. In this work, a series of hydrocarbon injection experiments performed on 5-spot glass micromodels that were initially saturated with the heavy crude oil. The fractured micromodels with different fracture geometrical characteristics were used in the tests. High quality image analysis was applied to determine the fluid flow behavior, solvent front movement, and viscous fingering associated with solvent movement in matrix and fractures. Observations showed that higher solvent dispersion in the fractures rather than matrix...
Monitoring wettability alteration by silica nanoparticles during water flooding to heavy oils in five-spot systems: A pore-level investigation
, Article Experimental Thermal and Fluid Science ; Vol. 40, issue , July , 2012 , p. 168-176 ; ISSN: 08941777 ; Mohammadi, S ; Ghazanfari, M. H ; Kharrat, R ; Masihi, M ; Sharif University of Technology
Abstract
It is well known that the displacement efficiency of EOR processes is mainly affected by wettability of porous medium; however, the role of nanoparticles on wettability alteration of pores surfaces remains a topic of debate in the literature. Furthermore, a little is known about how the dispersed silica nanoparticles affect the microscopic/macroscopic recovery efficiency of heavy oils during common immiscible EOR processes such as water flooding. In this study, a series of injection experiments was performed on five-spot glass micromodel which is initially saturated with the heavy oil. Distilled water and dispersed silica nanoparticles in water (DSNW) at different values of weight percent...
Experimental study of miscible displacement with hydrocarbon solvent in shaly heavy oil reservoirs using five-spot micromodels: The role of shale geometrical characteristics
, Article Journal of Porous Media ; Vol. 15, issue. 5 , 2012 , p. 415-427 ; ISSN: 1091028X ; Ghazanfari, M. H ; Masihi, M ; Kharrat, R ; Sharif University of Technology
Abstract
Most of the heavy oil reservoirs contain discontinuous shale which affects fluid flow through porous media as well as recovery efficiency during enhanced oil recovery processes. However, the role of shale geometrical characteristics (including orientation, length, discontinuity, and spacing of the shale) on oil recovery remains a topic of debate in the literature, especially during miscible injection of heavy oils and five-spot systems. Here, a series of hydrocarbon solvent injection tests have been performed on various five-spot glass micromodels containing barriers which are initially saturated with heavy oil under fixed flow rate conditions. Oil recoveries as a function of pore volumes of...
The semi-analytical modeling and simulation of the VAPEX process of ""Kuh-e-Mond"" heavy oil reservoir
, Article Petroleum Science and Technology ; Vol. 29, issue. 5 , Oct , 2009 , p. 535-548 ; ISSN: 10916466 ; Masihi, M ; Kharrat, R ; Sharif University of Technology
Abstract
The vapor extraction process (or VAPEX) uses vaporized solvents injected into a horizontal well to form a vapor chamber within the reservoir. Vapor dissolves in the oil and enhances the oil production by decreasing the oil viscosity in heavy oil reservoirs. To evaluate the process we conduct a simulation study on an Iranian heavy oil reservoir called Kuh-e-Mond. In addition, a semi-analytical investigation of the VAPEX process has been performed. The idea is to perform VAPEX simulation for a laboratory model and find a methodology to compare the results of the simulator with the semi-analytical Butler's model. In particular, a semi-analytical dimensionless correlation for production rate...
Iterative coupled experimental-numerical evaluation of dispersivity in fractured porous media using micromodel system
, Article 73rd European Association of Geoscientists and Engineers Conference and Exhibition 2011: Unconventional Resources and the Role of Technology. Incorporating SPE EUROPEC 2011 ; Vol. 4, issue , 2011 , p. 2461-2466 ; Ghazanfari, M. H ; Masihi, M ; Kharrat, R ; Kianinejad, A ; Sharif University of Technology
Abstract
In this study a new iterative algorithm is developed to evaluate dispersivity in fracture and matrix, distinctly. The novelty of proposed algorithm is using mathematical model of solute transport in fractured porous media coupled with experimental data iteratively. A fractured glass micromodel has been designed to visualize the interaction between fracture and matrix during displacement of n-Decane by n-Octane at constant rate. The similarity between numerical and experimental model has been enhanced by reducing the assumptions which were applied in previous related studies. The iteration is performed on velocity components of solute transport and longitudinal as well as transversal...
An experimental investigation of sequential CO2 and N 2 gas injection as a new EOR Method
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, Issue. 17 , 2014 , pp. 1938-1948 ; ISSN: 15567230 ; Shadizadeh, S. R ; Vosoughi, M ; Kharrat, R ; Sharif University of Technology
Abstract
Typical non-hydrocarbon gases, which have been utilized in miscible and immiscible processes, are carbon dioxide and nitrogen. These gases are usually injected separately and have been rarely utilized together as a tertiary recovery process. In this article, the authors have experimentally focused on sequential carbon dioxide and nitrogen gas injection as a new enhanced oil recovery method. The periodic injections of carbon dioxide and nitrogen have been repeated for six injection pore volumes. Sensitivity analysis of injection pressure, injection volume, and injection rate has also been investigated in core flood experiments. The experimental results have revealed that a sequential miscible...
Toward mechanistic understanding of heavy crude oil/brine interfacial tension: The roles of salinity, temperature and pressure
, Article Fluid Phase Equilibria ; Vol. 375, issue , 2014 , Pages 191-200 ; ISSN: 03783812 ; Hemmati-Sarapardeh, A ; Ghazanfari, M. H ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
Abstract
Injecting low salinity brines is regarded as an enhanced oil recovery (EOR) process through IFT reduction. However, the exact mechanism behind this process is an unsettled and complex issue that has not been well understood yet, especially for heavy crude oil system. Besides, limited information is available regarding the key heavy oil/brine interfacial tension (IFT). The present study aims to investigate the sensitivity of dead heavy crude oil/brine IFT to a wide range of properties/conditions and to reveal the underlying physicochemical mechanisms involved in enhanced oil recovery and IFT reduction by low salinity water injection into heavy oil reservoir. IFT was measured as a function of...
Effects of paraffinic group on interfacial tension behavior of CO 2-asphaltenic crude oil systems
, Article Journal of Chemical and Engineering Data ; Vol. 59, issue. 8 , 2014 , Pages 2563-2569 ; ISSN: 00219568 ; Zebarjad, F. S ; Taghikhani, V ; Ayatollahi, S ; Sharif University of Technology
Abstract
The interfacial tension (IFT) of a crude oil/CO2 system is recognized as the main property affecting the efficiency of CO2 flooding during an enhanced oil recovery (EOR) process. The addition of a paraffin group hydrocarbon to asphaltenic crude oils as an asphaltene precipitant component is aimed to mimic the asphaltene precipitation process during crude oil production and transportation. Asphaltene precipitation would critically affect the interfacial behavior of crude oil/CO2 systems. In the first part of this study, the equilibrium densities of oil samples which contain n-heptane at different ratios were measured over varying pressures at 323 K. Then, the equilibrium IFT between CO2 and...
Investigation of the applicability of nano silica particles as a thickening additive for polymer solutions applied in EOR processes
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, Issue. 12 , 2014 , Pages 1315-1324 ; ISSN: 15567036 ; Kharrat, R ; Ghazanfari, M. H ; Sharif University of Technology
Abstract
In past decades, many attempts have been made to use water-soluble polymers as a mobility control agent to improve sweep efficiency of enhanced oil recovery processes. However, sensitivity of the thickening behavior of these polymers to some harsh conditions, such as high salinity, has cast serious doubt on their applicability in reservoir conditions. By expansion of nanotechnology, scientists discovered that nanoparticles can be utilized as thickening and rheology control agents in many polymer solutions. In this study, hydrophilic fumed silica is added to hydrolyzed polyacrylamide and sulfonated polyacrylamide solutions. The effect of the addition of nano silica on the thickening and...
A statistical inference approach for the identification of dominant parameters in immiscible nitrogen injection
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, Issue. 12 , 2014 , Pages 1285-1295 ; ISSN: 15567036 ; Ghazvini, M. G ; Dabir, B ; Emadi, M. A ; Rashtchian, D ; Sharif University of Technology
Abstract
Screening analysis is a useful guideline that helps us with proper field selection for different enhanced oil recovery processes. In this work, reservoir simulation is combined with experimental design to estimate the effect of reservoir rock and fluid properties on performance of immiscible nitrogen injection. Reservoir dip, thickness, and horizontal permeability are found to be the most influential parameters. Possible interactions of parameters are also discussed to increase reliability and robustness of screening results. Finally, significance of both main effects and interactions are evaluated by employing a statistical inference approach (hypothesis testing) and results are compared to...
Numerical simulation of surfactant flooding in darcy scale flow
, Article Petroleum Science and Technology ; Vol. 32, Issue. 11 , 2014 , Pages 1365-1374 ; ISSN: 10916466 ; Foroughi, S ; Beiranvand, M. S ; Sharif University of Technology
Abstract
One of the methods that is used nowadays in enhanced oil recovery is surfactant flooding. The main mechanisms of surfactant flooding in reservoir consist of reduction of interfacial tension between water and oil and modification of rock wettability. In this study, the authors simulate the surfactant injection process in Darcy scale and in one-dimensional, multicomponent, multiphase state, and effects of physical phenomena such as adsorption, dispersion, convection, and exchange between fluids and solids are considered. Wettability alteration of reservoir rock due to presence of surfactant in injected fluid is detected in relative permeability and capillary pressure curves. First, the authors...
Enhanced heavy oil recovery in sandstone cores using TiO2 nanofluids
, Article Energy and Fuels ; Vol. 28, issue. 1 , 2014 , pp. 423-430 ; ISSN: 08870624 ; Ahadian, M. M ; Taghikhani, V ; Ghazanfari, M. H ; Sharif University of Technology
Abstract
Anatase and amorphous TiO2 nanoparticles were used to improve recovery of heavy oil from sandstone cores. Before performing core floods, the stability of nanoparticles at different salinities was tested using ζ potential and ultraviolet-visible (UV-vis) methods. While water recovered only 49% of the oil in the core flood experiments, 0.01% anatase structure solution recovered 80% of the oil after injecting two pore volumes at optimum conditions. To understand the mechanism responsible for improved recovery, contact angle measurements were performed on the rock surface before and after treatment with the nanoparticle solution. Contact angle measurements showed that the rock wettability...