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    The effect of calcite cementation on the mechanical behavior of gravely sands

    , Article 14th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, 23 May 2011 through 27 May 2011, Hong Kong ; 2011 Adl, M. R ; Sharif University of Technology
    Abstract
    The behavior of a cemented gravely sand is studied using triaxial tests. Undrained tests were performed on saturated specimens, and stress-strain characteristics of the soil, along with volumetric and pore pressure changes, were recognized. Artificially cemented samples are prepared using calcite crystallization as the cementing agent in different percentages. The tests were done in usual range of confining pressures, from 50 to 1200 kPa. The results shows that dilation occurs even at highest confining pressure and least cement content. Also the friction angle of soils increases slightly with cement content, but cohesion intercept increasing is more noticeable  

    The effect of dispersed phase salinity on water-in-oil emulsion flow performance: A micromodel study

    , Article Industrial and Engineering Chemistry Research ; Volume 56, Issue 15 , 2017 , Pages 4549-4561 ; 08885885 (ISSN) Maaref, S ; Ayatollahi, S ; Rezaei, N ; Masihi, M ; Sharif University of Technology
    American Chemical Society  2017
    Abstract
    In this work, the effect of brine salinity on water-in-oil emulsion flow performance in porous media is studied as it imposes a significant challenge to oil production in the petroleum industry. A crude oil sample from an Iranian oilfield and synthetic brine with different salinities (40-140 g/L salt) are used. The results show that the emulsion viscosity and interfacial tension increase slightly with salinity, while they do not considerably affect the flow behavior. The emulsion stability analysis shows that larger w/o emulsion droplets are formed for higher brine salinity, which potentially block more pore spaces through straining and interception mechanisms. This phenomenon resulted in... 

    Optimization assisted asphaltene deposition modeling in porous media during a natural depletion scheme

    , Article Petroleum Science and Technology ; Volume 30, Issue 9 , Mar , 2012 , Pages 958-965 ; 10916466 (ISSN) Hematfar, V ; Bagheri, M ; Kharrat, R ; Ghazanfari, M ; Ghotbi, C ; Sharif University of Technology
    2012
    Abstract
    Changes in thermodynamic properties such as pressure, temperature, and composition may result in asphaltene precipitation and deposition in porous media. In addition, asphaltene deposition can cause wettability alteration, permeability reduction, and ultimately a decrease in the productivity of a reservoir. Natural depletion is one of the most common processes of asphaltene deposition in which pressure changes destabilize the dissolved asphaltene in the oil and settle them onto the rock surface. In this work, natural depletion experiments in consolidated core samples were performed under simulated reservoir conditions to obtain reliable data and analyze the asphaltene deposition mechanisms.... 

    The impact of CO2 injection and pressure changes on asphaltene molecular weight distribution in a heavy crude oil: An experimental study

    , Article Petroleum Science and Technology ; Volume 28, Issue 17 , 2010 , Pages 1728-1739 ; 10916466 (ISSN) Sadeqimoqadam, M ; Firoozinia, H ; Kharrat, R ; Ghazanfari, M. H ; Sharif University of Technology
    Abstract
    This work concerns observing the pressure as well as CO2 mole percentage effects on asphaltene molecular weight distributions at reservoir conditions. A high-pressure, high-temperature asphaltene measurement setup was applied, and the amount of precipitated asphaltene at different pressures as well as CO2 mole percentage in an Iranian heavy crude oil was measured. Moreover, the asphaltene molecular weight distributions during titration of crude oil with different n-alkanes were investigated. The gel permeation chromatography (GPC) apparatus was used for characterization of asphaltene molecular weight under different conditions. It has been observed that some thermodynamic changes such as...