Sharif Digital Repository

Asphaltene deposition on reservoir rocks occurs during natural depletion as well as miscible injection processes. It causes reduction of effective pore space and consequent impairment of the ability of oil to flow through reservoir. Therefore, deposition of asphaltene causes significant formation damage and wellbore plugging, requiring expensive and difficult cleanup procedures. Thus it is necessary to be able to consider the onset, amount of deposition and also consequent damage of permeability and porosity reduction due to various factors. The objective of current work is to conduct experimental and simulation study of asphaltene deposition dynamics in one of the Iranian reservoirs. In... 

The rheology of oil well cement (OWC) slurries is generally more complicated than that of conventional cement paste. In order to contend with bottom hole conditions, a number of additives are usually used in the OWC slurries. The objective of this research is to develop a fundamental understanding of the important mechanisms that affect the properties of OWC slurry such as rheological properties, free water, compressive strength and thickening time incorporating various chemical and mineral admixtures. The partial replacement of OWC using different nanoparticle weight percent has been proved to be a promising method. The mechanisms underlying the effects of chemical admixtures on the... 

In this study, two approaches were applied for estimating Minimum Miscibility Pressure (MMP). An oil sample from Yadavaran Field has examined by means of Carbon Dioxide Gas, South Pars Gas, and Association Gas in experimental approach. The experimental method used for estimating MMP is Slim-Tube. This kind of method is applied in industry widely. The results indicate that the MMP of Carbon Dioxide is low which denotes that the gas is even miscible around the Bubble Point Temperature of the oil sample. Moreover, the MMP of Association Gas and South Pars Gas is 3962 and 5150 psia, respectively. In simulation approach, Cell to Cell simulation method is used to estimate the MMP of the oil sample... 

Gas injection processes are considered as the second largest Enhanced Oil Recovery processes after thermal processes. In Dealing with the problems of Continuous Gas Injection (CGI) processes, the substitute method of Water Alternating Gas (WAG) is gaining ever increasing attention in field applications. The Hybrid method has the advantages both CGI and WAG processes. Laboratory studies of gas injection methods to show the optimum method and the effect of pressure on the performance of this method is the main objective of this project. Results obtained from these tests can be used in the Enhanced Oil Recovery scenarios for this reservoir. In this project, experiments for Continuous Gas... 

In recent decades, desulfurization processes have become necessary to reduce environmental pollution due to fuel sulfur emissions. In this research, in order to photocatalytic oxidation desulfurization of liquid fuel, a model fuel (normal octane) under visible light irradiation of 250 W sodium lamp, using H2O2 oxidant and methanol solvent in the presence of BMO/Fe@MIL(x%) composite. BMO and Fe@MIL were investigated. From the tests, X-ray diffraction, scanning and transmission electron microscope imaging, absorption and desorption of nitrogen gas, infrared spectrometer-Fourier transform, visible-ultraviolet reflection spectroscopy, optical radiation spectroscopy and vibration magnetometer in... 

Matrix acidizing as a well stimulation technique is performed to increase the production index by increasing the permeability and removing the formation damage in the near wellbore region. However, several challenges such as corrosion of the tubulars and iron precipitation in the formation are hindering this process. To encounter these challenges, different chemicals, or additives, such as corrosion inhibitors and iron control agents are added to the acid solution. Carbonate acidizing has been carried out using HCl-based stimulation fluids for decades. However, at high temperatures, HCl does not produce satisfactory results because of its fast reaction, acid penetration, and hence surface... 

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... 

Formation acidizing is one of the best well stimulation methods to remove reservoir damage and improve recovery of oil and gas well. The proper design of acidizing operations can significantly improve the production of a formation. In the meantime, causing formation damage and precipitation in oil flowlines, which may be caused by the incompatibility of the stimulation fluid with the reservoir fluid and rocks, is one of the most serious problems in the operation, which reduces permeability and oil/gas production. As a result, the success of the acidizing operation requires to study the interaction of components of operation (acid, reservoir water, formation rock, and acid additive)... 

Wellbore instability is one of the serious problems during drilling. This can cause delay in drilling, increasing drilling costs and in some cases well abandonment. The present project investigates the effects of non- isothermal drilling and the difference in salt concentration between formation fluid and drilling fluid on the stability of wellbores drilled in the saturated porous shale formations subjected to an arbitrary stress field. This project also focuses on the analysis of wellbore stability in shale formations in which the thermal diffusivity is higher than fluid invasion and the mechanism of heat transfer is dominated by conduction. The governing equations used in this dissertation... 

Saturation molality for a number of single and mixed aqueous electrolyte solutions containing NaCl, Na2CO3, and K2SO4, was measured at atmospheric pressure over a wide range of temperature. In order to check the repeatability of the experimental data, the experiments were replicated three times and average of the results was considered as final saturation molality. Experimental data of saturation molality for single electrolyte solutions were correlated using the modified UNIFAC–Dortmund model to account for the shortrange interaction. Binary interaction parameters, between water molecules and ionic species were also reported. For the long-range interactions between the ionic species in... 

The aim of this project is to inventigate and synthesize CaO-based nanocatalysts with metal promoters of magnesium and lithium by wet impregnation and coprecipitation methods, which are used in the transesterification reaction of canola oil and methanol. Sections of thesis include review of before researches , synthesis of nanocatalysts, catalyst characterization tests,and investigation of reaction under optimal conditions. In wet impregnation method, nanocatalysts were made with 5% by weight of lithium-magnesium on the basis of CaO and with different weight percentages of these two elements. In the co-precipitation method , catalysts with a combined base of calcium oxide/magnesium oxide ... 

In recent decades, desulfurization processes have become essential to decrease environmental pollution due to the emission of sulfur from fuels. In this study, in order to desulfurize liquid fuel, a model fuel (normal heptane) was investigated under visible light ) 350-watt sodium lamp(, using H2O2 as oxidant and methanol as a solvent in the presence of Cu-C-TiO2 nanostructure. C-TiO2 was synthesized by the hydrothermal method. In order to modify and improve the properties, we doped the copper metal by impregnation method with different loading of Cu. Experimental results exhibited the highest activity among samples attributed to 0.5% Cu-C-TiO2 Which caused 98.27% degradation of DBT after 2... 

In present work, nanostructured multilayer composites produced from AA1100 and St37 alloys and mechanical properties of resulted samples characterized using tension and micro hardness tests. Also dispersion pattern of second phase in matrix studied via optical microscopy. Thickness of second phase layers showed a little reduction after 2 ARB cycles; but their length decrease gradually. With increasing number of ARB cycles up to 6 cycles, sample's tensile strength first decrease rapidly and after that increased, but never reached initial value. In order to evaluation of heat treatment effects on samples grain structure, samples heat treated and tensile test carried on them. Annealing at 300... 

Ni-Ti shape memory alloys have attracted most of the research in the field of shape memory alloys both because of their complicated and diverse phase transformation characteristics and their optimum properties for various applications which span such a properties as shape memory effect, pseudoelasticity, excellent mechanical properties and biocompatibility. The key properties of these alloys is generated through a thermoelastic martensitic transformation the occurrence of which is extremely sensitive to the metallurgical conditions of the alloy e.g. composition and microstructure. This has led to the development of various procedures implemented in either fabrication, processing or heat... 

MP210 alloy is a member of multiphase family alloys, a class of wrought nickel-cobalt base alloys extensively used in high-quality applications including aerospace fasteners, gas turbine engines and petrochemical industry. Very limited information can be found in the literature about the microstructure and phase transformations of this alloy. The aim of this work is characterizing the aging response of the material and identifying the major strengthening phases precipitated in different range of temperatures and also studying the static recrystallization behavior of this alloy. The effect of age-hardening heat-treatment on the microstructure of MP210 superalloy was investigated using... 

Previous observation and models on the origin of linear hardening behavior in FCC polycrystals are critically reviewed. To reveal the draw backs of the previous models, selected results of an investigation on the evolution of microstructure during simple compression testing of two FCC polycrystals, Inconel 625 superalloy and AISI 316L stainless steel are reported. It is found that while a number of FCC polycrystals show linear hardening behavior, the evolution of the underlying microstructure may be quite different. It is argued that, in contrast to the current belief, deformation twinning may not be the sole cause of linear hardening in low SFE FCC polycrystals. It is suggested that only... 

In this study nanostructured composite from Al1050 and Al2024 were manufactured via accumulative roll bonding (ARB). Process was conducted in two different ways. In one approach the Al2024 sheets were annealed and in the other they were solution treated (ST). The sheets were degreased by acetone and wire-brushed, and then one Al2024 was placed between two sheets of Al1050, so three pieces of sheets were stacked to be 3 mm in thickness. The stacked sheets were rollbonded to produce the primary composite sandwich with thickness of 1 mm. Then, this sandwich was cut in the half and the two halves were degreased and wire-brushed and stacked to be 2 mm in thickness. Roll-bonding was conducted... 

Recently lithium iron silicate (Li2FeSiO4) has been used as a new cathode material for lithium ion battery. Li2FeSiO4 has such benefits like low raw material price so lower production cost, lower environmental pollution, higher safety, electro chemical and cyclic stability and high theoretical capacity of 166 mAh/g against other cathode materials like LiMn2O4, LiBNiO2, LiCoO2 and LiFePO4. In this research Li2FeSiO4 was synthesized through sol gel synthesis method and effect of chelating agent concentration, calcination temperature and time has been investigated. To determine the appropriate calcination temperature range, TG/DTA was performed. Then the dried gel powder was calcined at each... 

The heteronuclear complexes [MePt(bhq)(μ-dppy)Au(PPh3)]PF6, 2, [MePt(bhq)(dppy)Tl]PF6, 3 and [Me2Pt2(bhq)2(dppy)2Tl]PF6, 4 in which bhq=benzo{h}quinoline and dppy=2-diphenylphosphinopyridine, were prepared by reaction of the mononuclear complex [MePt(bhq)(dppy)] 1 with 1 equivAuCl(PPh3), 1equiv TlPF6 and 1/2 equiv TlPF6 respectively. All the complexes were fully characterized using multinuclear NMR spectroscopy and ESI-MS spectrometry. In addition molecular structures of complexes 2 and 3 in solid state have been determined by X-ray crystallography that shown strong dative bonds between platinum and gold or thallium atoms. As shown by ESI-MS spectrometry, the Pt-Au bond in complex 2...