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Total 23 records

    Interfacial tension and wettability change phenomena during alkali-surfactant interactions with acidic heavy crude oil

    , Article Energy and Fuels ; Vol. 29, issue. 2 , January , 2015 , p. 649-658 ; ISSN: 08870624 Dehghan, A. A ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
    Abstract
    In this work, a newly formulated sulfonate-based surfactant and two other commercial sulfate-based surfactants with the capability of tolerating harsh underground reservoir conditions, such as high-saline formation water and high temperature, were prepared. Sodium metaborate as an effective alkali compound was also used to provide alkali-surfactant combination. Interfacial tension (IFT) measurements as well as wettability examinations for different salinities and mixture conditions were performed for an extended range of the chemical concentrations. The wettability tests including both contact angle measurements and Amott cell tests were performed on saturated Berea sandstone plug samples... 

    Experimental investigation of water alternating CH4-CO 2 mixture gas injection in light oil reservoirs

    , Article International Journal of Oil, Gas and Coal Technology ; Vol. 8, issue. 1 , 2014 , p. 31-40 Alizadeh, A ; Ghazanfari, M. H ; Taghikhani, V ; Badakhshan, A ; Sharif University of Technology
    Abstract
    This paper studies a WAG process for improving the recovery efficiency in light oil reservoirs. Until now, few references have reported the role of CO2 mole percent on recovery improvement in light oil reservoirs. The injected gas was changed, and the effect of composition changes on performance of core flood experiments were conducted at fixed flow rate. Five series of experiments (varied in methane mole percentages, 0, 25, 50, and 75, 100) were systematically examined. The results indicated that the oil recovery efficiency improved with the increasing of CO2 mole ratio and there was also maximum recovery efficiency in this work. That would be helpful to better understanding the role of CO2... 

    Interfacial tension and wettability change phenomena during alkali-surfactant interactions with acidic heavy crude oil

    , Article Energy and Fuels ; Volume 29, Issue 2 , 2015 , Pages 649-658 ; 08870624 (ISSN) Dehghan, A. A ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
    American Chemical Society  2015
    Abstract
    In this work, a newly formulated sulfonate-based surfactant and two other commercial sulfate-based surfactants with the capability of tolerating harsh underground reservoir conditions, such as high-saline formation water and high temperature, were prepared. Sodium metaborate as an effective alkali compound was also used to provide alkali-surfactant combination. Interfacial tension (IFT) measurements as well as wettability examinations for different salinities and mixture conditions were performed for an extended range of the chemical concentrations. The wettability tests including both contact angle measurements and Amott cell tests were performed on saturated Berea sandstone plug samples... 

    On the determination of CO2-crude oil minimum miscibility pressure using genetic programming combined with constrained multivariable search methods

    , Article Fuel ; Volume 173 , 2016 , Pages 180-188 ; 00162361 (ISSN) Fathinasab, M ; Ayatollahi, S ; Sharif University of Technology
    Elsevier Ltd 
    Abstract
    In addition to reducing carbon dioxide (CO2) emission, the high oil recovery efficiency achieved by CO2 injection processes makes CO2 injection a desirable enhance oil recovery (EOR) technique. Minimum miscibility pressure (MMP) is an important parameter in successful designation of any miscible gas injection process such as CO2 flooding; therefore, its accurate determination is of great importance. The current experimental techniques for determining MMP are expensive and time-consuming. In this study, multi-gene genetic programming has been combined with constrained multivariable search methods, and a simple empirical model has been developed which provides a reliable estimation of MMP in a... 

    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 Hemmati-Sarapardeh, A ; 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... 

    Experimental investigation of secondary and tertiary oil recovery from fractured porous media

    , Article Journal of Petroleum Exploration and Production Technology ; Volume 3, Issue 3 , September , 2013 , Pages 179-188 ; 21900558 (ISSN) Maroufi, P ; Ayatollahi, S ; Rahmanifard, H ; Jahanmiri, A ; Riazi, M ; Sharif University of Technology
    2013
    Abstract
    Naturally fractured reservoirs (NFRs) contribute in large extent to oil and gas production to the ever increasing market demand of fossil energy. It is believed that the vertical displacement of oil during gas injection assisted by gravity drainage (GAGD) is one of the most efficient methods for oil recovery in these reservoirs. Hence, in this work, unconsolidated packed models of cylindrical geometry surrounded by fracture were utilized in order to perform a series of flow visualization experiments during which the contribution of different parameters such as the extent of matrix permeability, physical properties of oil (viscosity, density, and surface tension) and the withdrawal rate was... 

    An experimental investigation of the effect of fracture dip angle on oil recovery and drainage rate in free fall gravity drainage in fractured reservoirs using a glass micromodel (A pore level investigation)

    , Article Petroleum Science and Technology ; Volume 31, Issue 4 , 2013 , Pages 355-367 ; 10916466 (ISSN) Zareh, N ; Kharrat, R ; Ghazanfari, M ; Sharif University of Technology
    2013
    Abstract
    Gravity drainage is the main production mechanism in the gas invaded zone in naturally fractured reservoirs. However, there are large ambiguities and complexities, resulting from the dynamic of oil depletion from matrix blocks toward the fracture network. Visualization of drained oil at pore scale using glass micromodels provides the opportunity to better understand the effects of different parameters which might affect oil recovery from fractured reservoirs. In this work a micromodel apparatus generated by laser etching is used to perform some gravity drainage tests on the network patterns. The experiments were performed on double block systems using crude oil. The block to block... 

    Experimental study of solvent flooding to heavy oil in fractured five-spot micro-models: The role of fracture geometrical characteristics

    , Article Journal of Canadian Petroleum Technology ; Volume 49, Issue 3 , 2010 , Pages 36-43 ; 00219487 (ISSN) Farzaneh, S. A ; Kharrat, R ; Ghazanfari, M. H ; Sharif University of Technology
    2010
    Abstract
    The solvent-based process appears to be an increasingly feasible technology for the extraction of heavy oil reserves. However, there is a lack of fundamental understanding of how fracture geometrical characteristics control the oil recovery efficiency in this type of enhanced oil recovery (EOR) technique. In this work, a series of experiments were performed whereby the pure and mixed hydrocarbon solvents (HCS) displaced heavy oil in fractured five-spot glass micro-models. Successive images of the solvent injection process were recorded. The oil recovery factor, as a function of injected pore volume of solvents, was measured using image analysis of the provided pictures. It has been observed... 

    Visualization and quantification of asphaltinic-heavy oil displacement by co-solvents at different wettability conditions

    , Article Petroleum Science and Technology ; Volume 28, Issue 2 , 2010 , Pages 176-189 ; 10916466 (ISSN) Dehghan, A.A ; Kharrat, R ; Ghazanfari, M.H ; Sharif University of Technology
    2010
    Abstract
    Despite numerous experimental studies, there is a lack of fundamental understanding on how the chemical composition of a co-solvent at different wettability conditions might affect the pore-scale events and oil recovery efficiency in 5-spot models. In this study visualization of solvent injection experiments performed on a one-quarter five spot glass micromodel, which was initially saturated with the crude oil. One hydrocarbon solvent was considered as base, and four other groups of commercial chemicals, as well as their mixtures, were used as co-solvents. Microscopic and macroscopic displacement efficiency of solvent mixtures in both strongly water-wet and oil-wet media has been studied. It... 

    Wettability alteration and oil recovery by spontaneous imbibition of low salinity brine into carbonates: Impact of Mg2+, SO4 2− and cationic surfactant

    , Article Journal of Petroleum Science and Engineering ; Volume 147 , 2016 , Pages 560-569 ; 09204105 (ISSN) Karimi, M ; Al-Maamari, R. S ; Ayatollahi, S ; Mehranbod, N ; Sharif University of Technology
    Elsevier B.V  2016
    Abstract
    A large amount of the discovered oil reserves are reserved in carbonate formations, which are mostly naturally fractured oil-wet. Wettability alteration towards more water-wet state reduces the capillary barrier, hence improving the oil recovery efficiency in such reservoirs. In this study, wettability alteration towards favorable wetting state was investigated by combining modified low salinity brine with surfactant during water flooding. The diluted brine was modified by increasing the concentration of Mg2+ and SO4 2−, individually as well as both ions in combination. Different brine formulations were tested experimentally through the observations of contact angle measurements and... 

    Application of different novel and newly designed commercial ionic liquids and surfactants for more oil recovery from an Iranian oil field

    , Article Journal of Molecular Liquids ; Volume 230 , 2017 , Pages 579-588 ; 01677322 (ISSN) Nabipour, M ; Ayatollahi, S ; Keshavarz, P ; Sharif University of Technology
    Elsevier B.V  2017
    Abstract
    This investigation is conducted on one of the southern Iranian oil fields, which experiences a fault on its gas cap. Therefore, no traditional gas injection and normal water injection for pressure maintenance is suggested. The target is set to inject special compatible and proper type of chemicals in each single well to avoid the pressure increase for the risk of oil and gas spill. Two different sources of aqueous phases, namely formation brine and sea water were used to find the effects of different brine composition on the main mechanisms of releasing the trapped oil, interfacial tension (IFT) and wettability alteration. The obtained results reveal that both the ionic liquid (IL) based... 

    Smartwater flooding in a carbonate asphaltenic fractured oil reservoir - Comprehensive fluidfluid-rock mechanistic study

    , Article 19th European Symposium on Improved Oil Recovery: Sustainable IOR in a Low Oil Price World, IOR NORWAY 2017, 24 April 2017 through 27 April 2017 ; 2017 ; 9789462822092 (ISBN) Mehraban, M. F ; Afzali, S ; Ahmadi, Z ; Mokhtari, R ; Ayatollahi, S ; Sharifi, M ; Kazemi, A ; Nasiri, M ; Fathollahi, S ; Sharif University of Technology
    European Association of Geoscientists and Engineers, EAGE  2017
    Abstract
    Waterflooding has been regarded as an efficient method for pressure maintenance of oil reservoirs. x Improved techniques such as Smart Water flooding as a new EOR/IOR process has gained more momentum based on the recent research activities in this field and the reduction of oil price. Despite many efforts on achieving the governing mechanisms of Smart Water flooding in many individual fields, most of data are sparse and more possible mechanisms which explains all the interactions yet to be introduced. This experimental study used a systematic laboratory framework which is based on seawater treatments at fixed ionic strength to eliminate the ionic strength effects, NaCl considered as the... 

    Smart water flooding performance in carbonate reservoirs: an experimental approach for tertiary oil recovery

    , Article Journal of Petroleum Exploration and Production Technology ; Volume 9, Issue 4 , 2019 , Pages 2643-2657 ; 21900558 (ISSN) Darvish Sarvestani, A ; Ayatollahi, S ; Bahari Moghaddam, M ; Sharif University of Technology
    Springer  2019
    Abstract
    Smart water flooding as a developing technique utilizes modified water chemistry in terms of salinity and composition to prepare the best-suited brine composition for a specific brine/oil/rock system to obtain higher oil recovery efficiency. Huge amount of unrecovered oil is expected to be remained in carbonate reservoirs; however, few research works on incremental oil recovery during smart water injection in carbonate cores at reservoir condition are reported. Several core flooding tests using one of the Iranian carbonate reservoir rock are conducted to check the effectiveness of smart water injection for more oil recovery efficiency. The results reaffirm the positive effect of sulfate ions... 

    Activating solution gas drive as an extra oil production mechanism after carbonated water injection

    , Article Chinese Journal of Chemical Engineering ; Volume 28, Issue 11 , 2020 , Pages 2938-2945 Shakiba, M ; Ayatollahi, S ; Riazi, M ; Sharif University of Technology
    Materials China  2020
    Abstract
    Enhanced oil recovery (EOR) methods are mostly based on different phenomena taking place at the interfaces between fluid–fluid and rock–fluid phases. Over the last decade, carbonated water injection (CWI) has been considered as one of the multi-objective EOR techniques to store CO2 in the hydrocarbon bearing formations as well as improving oil recovery efficiency. During CWI process, as the reservoir pressure declines, the dissolved CO2 in the oil phase evolves and gas nucleation phenomenon would occur. As a result, it can lead to oil saturation restoration and subsequently, oil displacement due to the hysteresis effect. At this condition, CO2 would act as in-situ dissolved gas into the oil... 

    Experimental investigation of factors affecting miscible two-phase flow in fractured and non-fractured micromodels

    , Article Proceedings of the 6th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM2008, 23 June 2008 through 25 June 2008, Darmstadt ; Issue PART B , 2008 , Pages 1027-1034 ; 0791848345 (ISBN); 9780791848340 (ISBN) Farzaneh, A ; Kharrat, R ; Ghazanfari, M. H ; ASME ; Sharif University of Technology
    2008
    Abstract
    Micromodel is small-scale artificial model of porous medium which is known as a novel approach for simulating flow and transport in porous media. For better understanding the effect of fracture geometrical properties on oil recovery efficiency, a series of first contact miscible solvent injection process were conducted on horizontal glass micromodels at several fixed flow rate conditions. The micromodels were initially saturated with the heavy crude oil. The produced oil as a function of injected volume of solvents was measured using image analysis of the provided pictures. The concentration calibration curves of solvents in heavy crude oil were used for evaluating the solvents... 

    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 Mohammadi, S ; 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... 

    Experimental investigation of matrix wettability effects on water imbibition in fractured artificial porous media

    , Article Journal of Petroleum Science and Engineering ; Volume 86-87 , 2012 , Pages 165-171 ; 09204105 (ISSN) Rezaveisi, M ; Ayatollahi, S ; Rostami, B ; Sharif University of Technology
    Abstract
    Spontaneous water imbibition into the matrix blocks is known as the main mechanism for increased oil recovery from naturally fractured oil reservoirs. The rate of oil recovery and its ultimate value is mostly affected by wettability of the rocks and their pore structure. Oil viscosity also greatly influences the rate of oil recovery. A novel experimental model was utilized to study the imbibition mechanism under different wettability conditions. Matrix blocks made from different grain types and size distributions of glass beads were saturated with two different types of synthetic oil, to mimic the oil-saturated matrixes. The wetting characteristic of the models used in this study were... 

    Pore-Scale Monitoring of Wettability Alteration by Silica Nanoparticles During Polymer Flooding to Heavy Oil in a Five-Spot Glass Micromodel

    , Article Transport in Porous Media ; Volume 87, Issue 3 , 2011 , Pages 653-664 ; 01693913 (ISSN) Maghzi, A ; Mohebbi, A ; Kharrat, R ; Ghazanfari, M. H ; Sharif University of Technology
    Abstract
    It is well known that the oil recovery is affected by wettability of porous medium; however, the role of nanoparticles on wettability alteration of medium surfaces has remained a topic of debate in the literature. Furthermore, there is a little information of the way dispersed silica nanoparticles affect the oil recovery efficiency during polymer flooding, especially, when heavy oil is used. In this study, a series of injection experiments were performed in a five-spot glass micromodel after saturation with the heavy oil. Polyacrylamide solution and dispersed silica nanoparticles in polyacrylamide (DSNP) solution were used as injected fluids. The oil recovery as well as fluid distribution in... 

    Wettability alteration in carbonates during "Smart Waterflood": Underling mechanisms and the effect of individual ions

    , Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 487 , 2015 , Pages 142-153 ; 09277757 (ISSN) Rashid, S ; Mousapour, M. S ; Ayatollahi, S ; Vossoughi, M ; Beigy, A. H ; Sharif University of Technology
    Elsevier  2015
    Abstract
    There are increasing evidences that adjusting the chemistry of the injecting water improves the oil recovery efficiency. However, the underlying mechanisms for this technique which is referred to as "smart waterflood" have not yet been thoroughly understood. It is needed to explore the role of individual ions through set of different tests, to find the right mechanisms behind "smart waterflood". This study is focused on the fluid/solid (carbonate) interactions through systematic wettability measurement. Contact angle measurements accompanied by spontaneous imbibition tests were employed to determine the role of individual monovalent and divalent ions in wettability alteration process by... 

    Experimental investigation of tertiary oil gravity drainage in fractured porous media

    , Article Special Topics and Reviews in Porous Media ; Volume 1, Issue 2 , 2010 , Pages 179-191 ; 21514798 (ISSN) Rezaveisi, M ; Rostami, B ; Kharrat, R ; Ayatollahi, Sh ; Ghotbi, C ; Sharif University of Technology
    2010
    Abstract
    The amount of residual oil trapped in the matrix of a fractured reservoir after water drive, either natural water drive or water injection, depends on the wettability of the matrix rocks. Gas oil gravity drainage (GOGD) has been proposed as the tertiary oil recovery process for this type of oil reservoir. The current work focuses on experimental investigation of tertiary GOGD in fractured porous media under different types of matrix wettability. Results of a set of experiments performed in artificial porous media composed of sand packs and glass beads of different wettability have been used to check the GOGD rate and the ultimate oil recovery for previously waterflooded models. A novel...