Sharif Digital Repository

Fractured reservoirs constitute a major portion of world’s petroleum reservoirs. Gravity drainage is the controlling production mechanism in these reservoirs. Thus, investigation of performance and oil production in fractured models has been the subject of many researches. Despite the considerable number of experimental and modeling studies in this area, the method of scale-up in single or multi block models is not broadly investigated. This work is divided into two experimental and modeling sections. For the experimental study, free fall gravity drainage experiments in synthetic single or multi block porous media were performed in order to investigate effects of different parameters... 

Low salinity water flooding (LSWF) is a relatively new EOR method in which low salinity or modified ionic composition water is injected into the reservoir to alter its wettability toward a more water-wettable state to accelerate oil recovery. Ease of field deployment and relatively low cost, as well as laboratory results confirming the positive effect of this method in improving the oil recovery factor, have made this technique attractive in the oil industry.Despite the many advantages of this method, overcoming the mixing between low and high salinity water which occurs due to a high mobility ratio between these two fluids is essential because it negatively affects the efficiency of LSWF.... 

About 20% of total oil in the world is reserved in fractured reservoirs and there is also more than 60% of remained oil in the world in these reservoirs. But increasing recovery factor and production from this type of reservoirs was not very successful. After water flooding process most of the oil remains in the reservoir. The amount of remained oil is much more specially in fractured reservoirs. Surfactant flooding in one of the well-known enhanced oil recovery methods for reduction of interfacial tension between fluids to decrease capillary forces that cause less oil trapping and higher oil recovery. But a comprehensive and accurate understanding of the mechanism of this process and... 

Gravity drainage is known as one of the major mechanisms of oil recovery in naturally fractured reservoirs which petroleum engineers conducted research in this realm. Block to block interaction such as capillary continuity and reinfiltration mainly control the efficiency of this mechanism. In this study, first of all, free fall and forced gravity drainage experiments have been conducted in a single block apparatus and effect of some parameters like, density viscosity relation, matrix permeability, vertical fracture aperture, presence of viscose force and type of injected gas were investigated, in the second step, three stack block apparatus were designed and constructed. This apparatus were... 

Peer-to-Peer networks are invented to enable participants (peers) to share their resources and find and use the shared resources of the others. So the main issue is the mechanism of finding granted resources of the other peers. In Peer-to-Peer networks, there is no central server to index shared resources of the peers. So peers should collaborate to provide a fully distributed mechanism for searching resources. Considering the huge size of peer-to-peer systems, it is apparent that efficiency of the search mechanism is very critical. In this thesis, to have efficient seach in Peer-to-Peer networks, we propose two approaches. Then based on these approaches, we propose the third approach to... 

In this thesis the effects of impurities and different defects on electrical and magnetic properties of monolayer and bilayer graphene is investigated. Calculations are performed using density function theory. Alloying monolayer graphene with boron and nitrogen the energy gaps of 0.7 and 0.6 eV are obtained, respectively. Moreover, we show that BN is a good candidate for opening the band gap in graphene. Alloying monolayer graphene with BN the energy gap of 1.2 eV is obtained. Another way of opening band gap is to somehow break the symmetry between layers of the bilayer graphene. By alloying one layers of bilayer graphene with B, N or B-N, although the symmetry of layers is broken, each... 

As steel shear walls are usually applied in the central cores of buildings (around the elevators and stairs), the use of opening as door is inevitable in steel shear wall spans. On the other hand, because of weakening the performance of steel shear walls due to the presence of these openings, it is necessary to apply stiffeners around it. The use of stiffeners around all sides of opening continued to beams and columns, is very expensive. Therefore, the necessity of studying on the effect of different arrangements of stiffeners on the behavior of steel shear walls is felt. In this research, a number of steel shear walls with different characteristics in terms of plate aspect ratio, location... 

Population growth require increasing demand of Energy. The fossil fuels are the main source of energy. However, they are main source of carbon dioxide emissions. Considerable amount of fossil fuels is used in the power plants. Increasing trend of electricity consumption as well as the lack of alternative fuels such as renewables in the short time will increase the consumption of fossil fuels and emissions. The most important greenhouse gas emitted from the power plants is carbon dioxide. That's why the separation of carbon dioxide from the gas stream of power plants is necessary.Separation of the carbon dioxide by adsorption is considered in this project both experimentally and... 

Due to the ability in producing nanostructured materials, Mechanical Alloying has gained outstanding position in comparison with other materials fabrication techniques. In this research,with different milling condition, Alloying of Ni-Ti-Ag was performed. In order tofabricating the alloy, twodifferent initial materials were employed.In one process, nickel, titanium and silver were used as raw materials, and in another, titanium hydride was used instead of titanium.Initial powders were investigated in planetary mill, SPEX mill and vibratory disc indifferent times. Using XRD, microstructure information and phase analysis was obtained. EDS was employed for determination of elemental...