Sharif Digital Repository

Crumb rubber, produced from shredding of scrap or refused tires, is one of the most commonly used modifiers of asphalt. Asphalt rubber, in addition to mitigating some of the environmental problems of disposing scrap tire, improves the flexural strength of pavement, extends the life of pavement and reduces the maintenance costs. The properties of asphalt rubber are highly dependent on the type and composition of base asphalt, type and amount of crumb rubber, and the production method.The goal of this research is to investigate the performance properties of asphalt rubbers produced from Iranian asphalt and crumb rubber, using an industrially feasible method. The Superpave testing procedure was... 

Impulsive waves generated by landslides and slamming on horizontal cylindrical members of a jacket are examples of phenomena which cause damage on structures and endanger human life. Importance of wave generated by land slide was a motivation for a large number of analytical, experimental and numerical studies. Recently, numerical methods that do not use a grid have been used in order simulation and prediction of damage in these sophisticated hydrodynamic problems. One of these modern methods is Smoothed Particle Hydrodynamics (SPH). A general model based on Smoothed Particle Hydrodynamics, “SPHysics”, was developed jointly by researchers to promote the development and use of SPH within the... 

In this study a new SPH model for solving free surface and fluid-fluid interaction problems is presented. The numerical model is capable of simulating two dimensional hydraulic problems with arbitrary boundary and initial conditions and large number of particles. It has the ability to model multi-fluids domain with different densities and viscosities. Several corrections are implemented in SPH formulation such as treatment of free surface and correction of viscous term in order to conserve the angular momentum. Several examples are conducted in fluid-fluid domains to measure the capability of model in this area of study. This new model use Incompressible SPH method for more accurate... 

Nowadays, foaming agents have wide applications in drilling, cementing, fracturing and oil displacement in the petroleum industry. Typical applications are to make light fluids for drilling operations in naturally fractured reservoirs where lost circulation is a problem. Compared with conventional and aerated drilling fluids, foamy mud is a compressible and relatively homogeneous mixture. A great flexibility for pressure control is thus possible. In this study, a new foaming agent of Yas-Khorramshahr Company is introduced to drilling fluids. Stability of this agent at different concentration and in presence of Salt and crude oil is tested. Also common drilling muds are lightened and... 

In this study, density, viscosity and surface tension of aqueous solution of Sulfolane, ( TEA+TMS+H2O) and (DIPA+TMS+H2O) systems were measured . Density, viscosity and surface tension were measured using pycnometer, Cannon – Fenske viscometer and Capillary rise method, respectively. Surface tension measurements of (DIPA+TMS+water) were carried out by the ring method using a LAUDR TD3 tensiometer,. The experiments were carried out in low concentrations and atmospheric pressure in the temperature range (70 - 30) . The obtained Data was modeled using empirical and thermodynamic models. Density calculation was done using the Setchenov and Redlich – Kister models.and the results indicated that... 

In this study, thermal and rheological properties of nanofluids of water/carbon nanotubes, water/spherical silica nanoparticles and water/hybrid nanoparticles (hybrid of carbon nanotubes and spherical silica nanoparticles) have been investigated. To do so, carbon nanotubes have been synthesized by CCVD process and spherical silica nanoparticles and hybrid nanoparticles by wet chemical method. After synthesis of nanomaterials, nanofluids have been prepared by using SDBS as a dispersant with the concentration of 1.5 times of concentration of nanomaterials and then thermal conductivity, kinematic viscosity, dynamic viscosity and density of nanofluids have been investigated. As the results show,... 

Effects of temperature on the behavior of soils and rocks have been studied widely in recent years. Following the need for understanding the effects of temperature on the behavior of clayey soils, several experimental and numerical studies on thermo-mechanical behavior of clayey soils have been carried out and a number of thermo-mechanical constitutive models have been developed for saturated and unsaturated clayey soils. In this research, a two-yield surface thermo-plastic constitutive model developed by Abuel-Naga et al. (2007, 2009), has been chosen for THM analysis of the behavior of saturated clayey soils. This constitutive model is based on Modified Cam-Clay (MCC) model. The MCC model... 

Polymer flooding is a famous enhanced oil recovery method and is used to reduce mobility ratio of displacing fluid to displaced fluid by forming a stable front in displacing process. Due to high costs, polymer flooding faces economical risks and from this point of view, performance investigation of polymer flooding in laboratory scale was concerned. In this project, performance of 7 types of polymers which have different rheological properties were investigated in fractured/non-fractured carbonated and sandstone reservoirs. These polymers consists of 4 commercial polymers, one branched polymer, one synthetic polymer and one polymer composite which have different molecular weight,... 

In this project, combination of PC-SAFT equation of state and friction theory was used for predicting the viscosity of reservoir fluid. Parameters of PC-SAFT and f-theory are available for pure components, but they are not known for oil cuts that are complex hydrocarbon mixtures. To solve this problem, in the first step, existing optimized parameters for PC-SAFT EOS of hydrocarbon mixtures were used and then, parameters of f-theory for mixtures were optimized. To set the parameters, two approaches were studied. The first approach is to obtain a series of empirical correlations that can estimate the parameters of f-theory (in conjunction with PC-SAFT) for oil cuts in terms of their molecular... 

In this project, the effect of improper lubrication on vibrational behavior of rolling element bearings is investigated. Different lubrication conditions were deliberately produced using three oils with different viscosity grades on a bearing at different loads and speeds. The acceleration of bearing vibrations were measured, then analyzed by means of squared envelope analysis, a special case of cyclostationary analysis. The results and their comparison showed that decrease in lubricant’s viscosity grade can lead to an increase in magnitude of cyclic frequencies equal to cage frequency and its harmonics. This observation can be helpful in detection of lubricant degradation and in... 

Capillary Imbibition is an important mechanism in producing oil from matrix blocks in fractured reservoirs. In a water-wet fractured reservoir, if the rise of water level in fracture is in a way that at all the moments the water front in fracture is lower than that in the matrix block we expect co-current imbibition. Iranian reservoirs have large matrix blocks and co-current imbibition can be expectable. Till this time, not many investigations have been done on co-current imbibition in and out of our country, Iran. In this thesis, an experimental investigation on co-current imbibition will be done for different conditions. The main goal of this thesis is the study of co-current imbibition in... 

Water in oil emulsion usually forms during natural water encroachment or enhanced oil recovery processes due to the reaction between asphaltenic and naphthenic acid part of oil with brine in some heavy oil reservoirs. This results in major production challenges because of high w/o emulsion viscosity which leads to significant pressure drops. Therefore, it is essential to investigate the dominant mechanisms of w/o emulsion flow in porous media to overcome the production challenges. In the present study, w/o emulsion behavior is investigated through both static and dynamic tests. The w/o emulsion was prepared through mixing of a crude with brine using magnet stirrer. Emulsion stability... 

Given that the mean of the cost of drilling operation related to the required martials and preparation of the drilling fluids, therefore, the design and construction drilling fluid which omit has to be a proper rheology is essential in drilling operations and oil industry. A desirable property of the drilling fluid is the minimum fluid loss volume which can be achieved by formation of a low permeability filter cake on the wellbore. Drilling fluid filtrating invasion into the formation can cause formation damage and reduction in the productivity of the well. In drilling fluids, a series of natural synthetic and polymers may be used as fluid (filtration) loss control additives. However, high... 

With the decline in oil discoveries during the last decades, it is believed that enhanced oil recovery (EOR) technologies will play a key role to meet the energy demand in coming years. Polymer flooding has been commonly used worldwide as one of the EOR processes. Literature reviews show that the active water-soluble polymers have a number of limitations related to their surface absorption, undesirable plugging, polymer concentration limitation,expensive, and low thermal, mechanical, bacterial, and salt tolerance. Up to now, five different polymer categories (i.e. polyacrylamide, hydrolyzed polyacrylamide, acrylamidebased resistant copolymers, associative copolymers, and thermoassociative... 

Surface phenomena is one of the fundamental branches of science that has many applications in industries related to multiphase processes. One of the most important issues of this knowledge is inter-phase transport phenomena in contacting gas - liquid and liquid – liquid systems. Multiphase systems generally include dispersions such that in many cases are associated with the relative motion between the continuous and dispersed phase. One of the most widely used inter-phase flow systems is dispersion of gas bubbles in the bulk of liquid. The overall efficiency of these systems is often determined by the characteristics of the gas phase. In order to understand the dynamic behavior of such... 

Ionic liquids due to their unique physical and chemical properties are widely used in various fields of chemistry and chemical engineering. Determining properties of ionic liquids can be difficult, time consuming or even impossible. In first step of this study the IL thermo database was chosen as source of experimental data of ionic liquids. Viscosity, density, surface tension and melting temperature of ionic liquids based on bis(trifluoromethylsulfonyl)imide anion with cations imidazolium, pyridinium, pyrrolidinium, piperidinium and ammonium were modeled using QSPR approach. Linear and nonlinear models were built by means of multiple linear regression (MLR), multilayer perceptron neural... 

experimental data of crude oil for viscosity are available in limited conditions of temperature and pressure. Therefore, the use of empirical equations and relations to predict it at temperatures and pressures beyond the temperature and pressure of the reservoir is inevitable. In order to reduce the cost of the laboratory, the use of a comprehensive model in this project is considered. For this purpose, using two theories of friction and free volume, the Peng Robinson and PC-SAFT equation of states and genetic algorithms and particle swarm optimization are widely used to calculate the viscosity of pure hydrocarbons, binary mixtures of hydrocarbons and crude oil have been used. Obviously, by... 

In this study, the effect of molybdenum disulfide nanosheets on the rheological behavior of suspensions was investigated using a polyethylene glycol matrix and glass grain fillers with a particle distribution of 60 to 103 microns. Crude molybdenum disulfide was obtained by single-layer and multilayered molybdenum disulfide nanosheets with thicknesses between 50 and 100 nm using acid, oxidation and heat shock methods. This claim was verified by various tests such as FT-IR, FESEM,EDS, TEM, DLS, XRD and so on. Subsequently, using 10 to 40% volumetric glass beads were prepared from the sample matrix. Stirring and ultrasonic, rheological behavior of these suspensions were investigated using... 

One of the best stimulation methods for oil and gas wells is matrix acidizing in order to increase the near wellbore permeability. in acidizing, good acid coverage in different layers is one the main goals. so, various methods have been presented. important part in using these methods is to not damage formation and economic matters. modern methods utilize VES acids for this purpose. viscoelastic characteristics of these materials by formation of miscellaneous, increases the apparent viscosity by a large degree. for this reason, VES fluids can be used to improve acid divergence in acid injection operation. acid system based on viscoelastic surfactants that is changed to gel instantly, can be... 

This study investigated the effect of oxidized molybdenum disulfide (MoS2) nanosheets on the anti-corrosion and rheological properties of epoxy resin. Raw MoS2 sheets were obtained as layered nanosheets with a thickness of 50 to 100 nm using acid washing, oxidation, and heat shock methods. The use of nanoparticle characterization tests such as XRD, FT-IR, FE-SEM, EDS, and TGA supports this claim. Then, in the next step, epoxy coatings containing different percentages (0, 0.3, 0.5, 0.8, and 1.5 wt%) of MoS2 nanosheets were prepared with polyamide hardener to investigate the effect of adding nanosheets and the optimal percentage. The best effect on the corrosion properties of the coating in a...