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    Investigating the mechanism of water inflow in gas wells in fractured gas reservoirs and designing a controlling method

    , Article SPE Production and Operations Symposium, Proceedings ; Vol. 1, issue , May , 2012 , p. 323-340 ; ISBN: 9781613992012 Jafari, I ; Jamshidi, S ; Masihi, M ; Sharif University of Technology
    Abstract
    The coning phenomenon usually occurs in water and gas cap drive reservoirs. Water coning in Iranian hydrocarbon reservoirs is one of the most important problems that affects the cumulative production, operation costs and causes environmental problems. Before producing from a reservoir, its fluids are in equilibrium and their contact surfaces remain unchanged, but after starting production from the reservoir, when the viscous force overcome gravitational force in vertical direction, contact surfaces will displace and coning will occur. So, the production rates will be controlled in a range that prevents entering water and gas to the production well. For this reason, investigation and modeling... 

    Investigating the mechanism of water inflow in gas wells in fractured gas reservoirs and designing a controlling method

    , Article SPE Production and Operations Symposium, Proceedings ; Volume 1 , 2012 , Pages 323-340 ; 9781622761272 (ISBN) Jafari, I ; Jamshidi, S ; Masihi, M ; Sharif University of Technology
    SPE  2012
    Abstract
    The coning phenomenon usually occurs in water and gas cap drive reservoirs. Water coning in Iranian hydrocarbon reservoirs is one of the most important problems that affects the cumulative production, operation costs and causes environmental problems. Before producing from a reservoir, its fluids are in equilibrium and their contact surfaces remain unchanged, but after starting production from the reservoir, when the viscous force overcome gravitational force in vertical direction, contact surfaces will displace and coning will occur. So, the production rates will be controlled in a range that prevents entering water and gas to the production well. For this reason, investigation and modeling... 

    Estimation of the Effective Permeability of Heterogeneous Porous Media by Using Percolation Concepts

    , Article Transport in Porous Media ; Volume 114, Issue 1 , 2016 , Pages 169-199 ; 01693913 (ISSN) Masihi, M ; Gago, P. A ; King, P. R ; Sharif University of Technology
    Springer Netherlands  2016
    Abstract
    In this paper we present new methods to estimate the effective permeability (keff) of heterogeneous porous media with a wide distribution of permeabilities and various underlying structures, using percolation concepts. We first set a threshold permeability (kth) on the permeability density function and use standard algorithms from percolation theory to check whether the high permeable grid blocks (i.e., those with permeability higher than kth) with occupied fraction of “p” first forms a cluster connecting two opposite sides of the system in the direction of the flow (high permeability flow pathway). Then we estimate the effective permeability of the heterogeneous porous media in different... 

    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 Rasti, F ; 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... 

    The semi-analytical modeling and simulation of the VAPEX process of "Kuh-e-Mond" heavy oil reservoir

    , Article Petroleum Science and Technology ; Volume 29, Issue 5 , 2011 , Pages 535-548 ; 10916466 (ISSN) Rasti, F ; 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... 

    The dependency of relative permeability on dominated flow regimes under gas gravity assisted flow

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 33, Issue 2 , Oct , 2011 , Pages 101-113 ; 15567036 (ISSN) Rostami, B ; Kharrat, R ; Pooladi Darvish, M ; Ghotbi, C ; Sharif University of Technology
    2011
    Abstract
    Gas-oil relative permeability is essential for performance predictions of reservoirs with solutions for gas drive, gas cap expansion, or gas injection. The nature of flow in reservoir is determined by the interplay of relative permeability and viscous, gravity, and capillary forces. Displacement experiments of the gas-oil system are performed on long core scale models by varying the petrophysical properties and flow conditions. Experiments are conducted in situations where capillary, gravity, and viscous forces are comparable. The effect of destabilized front velocity on relative permeability and residual saturation is investigated. The results indicate that the relative permeability varies... 

    Experimental and simulation studies of the effect of vertical permeability barriers on oil recovery efficiency during solvent injection processes

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 33, issue. 20 , Nov , 2009 , p. 1889-1900 ; ISSN: 15567036 Dehghan, A. A ; Farzaneh, S. A ; Kharrat, R ; Ghazanfari, M. H ; Masihi, M ; Sharif University of Technology
    Abstract
    Almost all of the heavy oil reservoirs contain discontinuous permeability barriers (shales) with different structures. However, the effect of shaly layer geometrical characteristics including: spacing from wells, discontinuity, orientation, shaly layers' spacing and length, and heterogeneous distribution on oil recovery factor in the presence of gravity force are not well understood. In this work, a series of solvent injection experiments were conducted on various vertical one-quarter five-spot glass micromodels, containing barriers, which were initially saturated with a heavy oil sample. The oil recovery was measured by analysis of the pictures provided continuously during the injection... 

    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 Moradi, S ; 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... 

    The simulation of microbial enhanced oil recovery by using a two-layer perceptron neural network

    , Article Petroleum Science and Technology ; Vol. 32, Issue. 22 , 2014 , pp. 2700-2707 ; ISSN: 10916466 Morshedi, S ; Torkaman, M ; Sedaghat, M. H ; Ghazanfari M.H ; Sharif University of Technology
    Abstract
    The authors simulated a reservoir by using two-layer perceptron. Indeed a model was developed to simulate the increase in oil recovery caused by bacteria injection into an oil reservoir. This model was affected by reservoir temperature and amount of water injected into the reservoir for enhancing oil recovery. Comparing experimental and simulation results and also the erratic trend of data show that the neural networks have modeled this system properly. Considering the effects of nonlinear factors and their erratic and unknown impacts on recovered oil, the perceptron neural network can develop a proper model for oil recovery factor in various conditions. The neural networks have not been... 

    Performance of near-miscible simultaneous water and CO2 injection for oil recovery in secondary and tertiary modes

    , Article 76th European Association of Geoscientists and Engineers Conference and Exhibition 2014: Experience the Energy - Incorporating SPE EUROPEC 2014 ; Nov , 2014 , p. 1007-1011 Seyyedsar, S. M ; Ghazanfari, M. H ; Taghikhani, V ; Sharif University of Technology
    Abstract
    Simultaneous water and CO2 injection has been performed on a sandstone core to evaluate oil recovery under the secondary and tertiary near-miscible injection modes. It is demonstrated that secondary SWACO2 injection as well as tertiary flood is an effective method for the oil/residual oil recovery from oil saturated/water-flooded porous media. In the secondary SWACO2 injection, the ultimate oil recovery increases by increasing SWAG ratio from 0.2 to 0.4 but due to some limits, e.g. topological effects, prohibiting contacting of injected gas with residual oil in pores, altering SWAG ratio from 0.4 to 0.6 showed no effect on ultimate oil recovery. Secondary SWACO2 injection can recover higher... 

    Experimental analysis of secondary gas injection strategies

    , Article Petroleum Science and Technology ; Volume 31, Issue 8 , 2013 , Pages 797-802 ; 10916466 (ISSN) Heidari, P ; Alizadeh, N ; Kharrat, R ; Ghazanfari, M. H ; Laki, A. S ; Sharif University of Technology
    2013
    Abstract
    CO2 injection is a potentially viable method of enhanced oil recovery for medium oil reservoirs. The authors compare the effect of gas injection strategy (simultaneous water-alternating gas [SWAG], water-alternating gas [WAG], and continuous gas injection [CGI]) on recovery in immiscible, near-miscible, and miscible modes of injection. It has been proved that CGI is not the most efficient injection scenario in oil-wet reservoirs. Miscible and near-miscible core flood tests demonstrated high oil recoveries in all injection strategies due to high capillary numbers achieved as a result of miscibility. The fluid mechanics of floods were discussed using pressure drop data, different mechanics was... 

    Experimental Investigation on the Effect of Asphaltene Types on the Interfacial Tension of CO2-Hydrocarbon Systems

    , Article Energy and Fuels ; Volume 29, Issue 12 , 2015 , Pages 7941-7947 ; 08870624 (ISSN) Mahdavi, E ; Zebarjad, F. S ; Ayatollahi, S ; Taghikhani, V ; Sharif University of Technology
    American Chemical Society  2015
    Abstract
    Interfacial tension (IFT) is known as the critical parameter affecting the efficiency of CO2 flooding during the enhanced oil recovery (EOR) process. Besides, the asphaltene precipitation phenomenon is reported as the most significant problem during CO2 injection into asphaltenic oil reservoirs. Accordingly, it is important to examine the effect of asphaltene precipitation on the IFT behavior of the oil-CO2 system at reservoir conditions. The main objective of this research work is to study of the effect of asphaltene and its type on the IFT behavior of the oil-CO2 system. The IFT between pure CO2 and a model oil both with and without asphaltene was measured using an axisymmetric drop shape... 

    Experimental investigation on the effect of asphaltene types on the interfacial tension of co2-hydrocarbon systems

    , Article Energy and Fuels ; Volume 29, Issue 12 , November , 2015 , Pages 7941-7947 ; 08870624 (ISSN) Mahdavi, E ; Zebarjad, F. S ; Ayatollahi, S ; Taghikhani, V ; Sharif University of Technology
    American Chemical Society  2015
    Abstract
    Interfacial tension (IFT) is known as the critical parameter affecting the efficiency of CO2 flooding during the enhanced oil recovery (EOR) process. Besides, the asphaltene precipitation phenomenon is reported as the most significant problem during CO2 injection into asphaltenic oil reservoirs. Accordingly, it is important to examine the effect of asphaltene precipitation on the IFT behavior of the oil-CO2 system at reservoir conditions. The main objective of this research work is to study of the effect of asphaltene and its type on the IFT behavior of the oil-CO2 system. The IFT between pure CO2 and a model oil both with and without asphaltene was measured using an axisymmetric drop shape... 

    Free fall and controlled gravity drainage processes in fractured porous media: Laboratory and modelling investigation

    , Article Canadian Journal of Chemical Engineering ; Volume 93, Issue 12 , October , 2015 , Pages 2286-2297 ; 00084034 (ISSN) Saedi, B ; Ayatollahi, S ; Masihi, M ; Sharif University of Technology
    Wiley-Liss Inc  2015
    Abstract
    Gravity drainage is known to be one of the most effective methods for oil recovery in fractured reservoirs. In this study, both free fall and controlled gravity drainage processes were studied using a transparent fractured experimental model, followed by modelling using commercial CFD software. The governing equations were employed based on the Darcy and mass conservation laws and partial pressure formulation. Comprehensive examination was done on variables such as fluid saturation, velocity, and pressure distribution in the matrix and fracture, as well as fluid front level and production rate. Additionally, effects of the model parameters on the gravity drainage performance were... 

    Evaluation of interfacial mass transfer coefficient as a function of temperature and pressure in carbon dioxide/normal alkane systems

    , Article Heat and Mass Transfer/Waerme- und Stoffuebertragung ; Volume 51, Issue 4 , April , 2015 , Pages 477-485 ; 09477411 (ISSN) Nikkhou, F ; Keshavarz, P ; Ayatollahi, S ; Raoofi Jahromi, I ; Zolghadr, A ; Sharif University of Technology
    Springer Verlag  2015
    Abstract
    CO2 gas injection is known as one of the most popular enhanced oil recovery techniques for light and medium oil reservoirs, therefore providing an acceptable mass transfer mechanism for CO2–oil systems seems necessary. In this study, interfacial mass transfer coefficient has been evaluated for CO2–normal heptane and CO2–normal hexadecane systems using equilibrium and dynamic interfacial tension data, which have been measured using the pendant drop method. Interface mass transfer coefficient has been calculated as a function of temperature and pressure in the range of 313–393 K and 1.7–8.6 MPa, respectively. The results showed that the interfacial resistance is a parameter that can control... 

    Effects of rock permeability on capillary imbibition oil recovery from carbonate cores

    , Article Scientia Iranica ; Volume 17, Issue 2 C , JULY-DECEMBER , 2010 , Pages 185-190 ; 10263098 (ISSN) Darvishi, H ; Goodarznia, I ; Esmaeilzadeh, F ; Sharif University of Technology
    2010
    Abstract
    In order to investigate the feasibility and effects of core permeability on capillary imbibition recoverable oil from carbonate cores, some laboratory tests were carried out at the EOR research laboratories of Sharif University, Iran. Outcrop rocks with different permeabilities were taken away from a recognized outcrop and used in these experiments. Special core analysis tests were run on two core samples to find out relative permeability and end point saturations. Wellhead separator oil and gas samples were collected and recombined to a reservoir gas - oil ratio. A core flooding system with a capability of free and forced imbibition testing was designed and installed. A number of free and... 

    PC-SAFT modeling of petroleum reservoir fluid phase behavior using new correlations for petroleum cuts and plus fractions

    , Article Fluid Phase Equilibria ; Volume 408 , 2016 , Pages 273-283 ; 03783812 (ISSN) Assareh, M ; Ghotbi, C ; Tavakkoli, M ; Bashiri, G ; Sharif University of Technology
    Elsevier 
    Abstract
    Parameters of the PC-SAFT Equation of State (EoS) for pure components are generally determined by matching the saturation pressure and liquid density experimental data. These experimental data are unavailable for petroleum cuts and plus fractions of the petroleum reservoir fluids. In this work, new correlations as functions of specific gravity and molecular weight were developed to estimate the PC-SAFT parameters of petroleum cuts with unknown composition. It was shown that the proposed correlations accurately estimate the PC-SAFT parameters of the pure components published in the literature. Then, the obtained correlations were used and the PVT experimental data for various real reservoir... 

    Investigation of streaming potential coupling coefficients and zeta potential at low and high salinity conditions: Experimental and modeling approaches

    , Article Journal of Petroleum Science and Engineering ; Volume 145 , 2016 , Pages 137-147 ; 09204105 (ISSN) Esmaeili, S ; Rahbar, M ; Pahlavanzadeh, H ; Ayatollahi, S ; Sharif University of Technology
    Elsevier 
    Abstract
    Streaming potential measurement is one of the electrokinetic techniques used to determine the average zeta potential of porous rock which can provide reliable information on reservoir flow behavior and wettability state of the rock surface. Streaming potential measurement using electrodes has recently been introduced in the oil reservoirs applications and there are still significant uncertainties during the measurements and interpretation of streaming potential results. The primary purpose of this work is to establish a setup to measure the streaming potential of porous media with low scattering and evaluate voltage measurements based on the paired stabilization and pressure ramping methods.... 

    A novel model for wellbore stability analysis during reservoir depletion

    , Article Journal of Natural Gas Science and Engineering ; 2016 , Pages 935-943 ; 18755100 (ISSN) ; Volume 35, Issue Part A Behnoud far, P ; Hassani, A. H ; Al Ajmi, A. M ; Heydari, H ; Sharif University of Technology
    Elsevier B.V 
    Abstract
    It is not common to build a geomechanical model for depleted reservoirs as logging and coring are costly and time consuming in such reservoirs. On the other hand, in regular analysis of wellbore stability, the effect of time is completely ignored. As a result, with time there will be some errors in the evaluation of wellbore stability in depleted reservoirs. In order to determine the optimum wellbore trajectory during the reservoir life, it is necessary to have a model which can estimate the rock properties based on the first full logging suite and also consider the depletion effect. In this study, a novel model is proposed which combines a mechanical earth model, borehole circumferential... 

    An improved component retrieval method for cubic equations of state with non-zero binary interaction coefficients for natural oil and gas

    , Article Journal of Petroleum Exploration and Production Technology ; Volume 6, Issue 2 , 2016 , Pages 243-251 ; 21900558 (ISSN) Assareh, M ; Ghotbi, C ; Bashiri, G ; Roayaie, E ; Sharif University of Technology
    Springer Verlag 
    Abstract
    Volumetric and equilibrium calculations for the natural gas and oil defined by a large number of components are not feasible in applications like compositional reservoir simulation. Therefore, the fluid mixture is grouped to reduce computational load and to make faster calculations. However, for several reasons, it is required to have the detailed fluid composition rather than the lumped one. In this work, an improved delumping method is presented to retrieve the phase composition of the detailed mixture based on the grouped mixture thermodynamic calculations. The method is based on previously proposed delumping techniques for non-cubic equation of state (Assareh et al. in Fluid Phase...