Sharif Digital Repository

Ground-borne vibrations resulting from the railway and road traffic have an adverse impact on the environment and nearby infrastructures. The focus of this study is on a specific part of the Tehran-Tabriz Railway located in the vicinity of Fath Highway, Tehran. In the investigated area, there are many residential buildings very close to the railway, and consequently, the train-induced vibrations make the people disturbed. After determining the soil layering and their properties using site investigation, the effect of geofoam trenches in mitigating train-induced vibrations was numerically investigated. The results showed that both the trench depth and width were important, especially at... 

In recent years, improving oil recovery (IOR) has become an important subject for the petroleum industry. One IOR method is infill drilling, which improves hydrocarbon recovery from virgin zones of the reservoir. Determining the appropriate location for the infill wells is very challenging and greatly depends on different factors such as the reservoir heterogeneity. This study aims to investigate the effect of reservoir heterogeneity on the location of infill well. In order to characterize the effect of heterogeneity on infill well locations, some geostatistical methods, e.g., sequential gaussian simulation, have been applied to generate various heterogeneity models. In particular, different... 

Production optimization is defined as the process of maximizing oil production over the long term while minimizing total production costs. The overall goal is to achieve the optimum profitability from the well or field. In this process, the reservoir system can be considered as a multiple input–output system. In this complex system injection and production wells are known as inputs and outputs. The output of the system is often affected by various parameters consisting reservoir conditions, petrophysics, and PVT data. The optimization of the injector rates and number and installation of submersible pumps are the main issues which have been studied in this paper. Determining the factor with... 

Cutting transport is an important goal in drilling operation especially in horizontal and deviated wells since it can cause problems such as stuck pipe, circulation loss and high torque and drag. To this end, this article focused on the affecting parameters on the cutting transport by computational fluid dynamic (CFD) modeling and real operational data. The effect of drilling fluid and cutting density on the pressure drop, deposit ratio and string stress on the cutting transport has been investigated. A systematic validation study is presented by comparing the simulation results against published experimental database. The results showed that by increasing two times of drilling fluid... 

To improve the thermal stability of starch in water-based drilling fluid, monoethanolamine (MEA) was added, and the effect was investigated by laboratory experiment. The experimental results show that the addition of monoethanolamine (MEA) increases the apparent viscosity, plastic viscosity, dynamic shear force, and static shear force of the drilling fluid, and reduces the filtration rate of drilling fluid and thickness of mud cake apparently. By creating hydrogen bonds with starch polymer, the monoethanolamine can prevent hydrolysis of starch at high temperature. Starch, as a natural polymer, is able to improve the rheological properties and reduce filtration of drilling fluid, but it works... 

Nowadays, economical extraction of the oil and gas, and their products is an important problem. Up to now, vertical wells have been used for oil extraction but some wells exist that they cannot be reached by using the vertical drilling. Horizontal and directional drillings are some techniques to reach these wells. In this article, dynamics of the horizontal drill string is studied. According to the forces that affect the dynamics of drilling, its longitudinal vibration is analyzed. After determination of the boundary conditions and normal modes of the system with using mode summation method, displacement of the bit is obtained. Finally, dynamics of the horizontal drill string is simulated... 

Infills are as important members in structural design as beams, columns and braces. They have significant effect on structural behavior. Because of lots of variables in infills like material non-linear behavior, the interaction between frames and infill, etc., the infills performance during an earthquake is complicated, so have led designers do not consider the effect of infills in designing the structure. However, the experimental studies revealed that the infills have the remarkable effect on structure behavior. As if these effects ignored, it might occur soft-story phenomena, torsion or short-column effects on the structures. One simple and appropriate method for considering the infills... 

The objective of the research is to determine the effect of friction stir processing (FSP) parameters and vibration on the machining behavior of AZ91 alloy. The article displays the state of the art of AZ91 alloy machinability including chip formation, chip morphology, and cutting forces. In this method, the vibration was applied to the process line through the fixture under the workpiece during the FSP. The three-dimensional finite element (FE) modeling was applied for simulating the small-hole drilling process of AZ91 alloy. The large deformation of work and the chip formation in drilling process is realized by incorporating Johnson-Cook material constitutive model and material failure... 

Past earthquakes had shown vulnerability of infill walls especially under out of plane (OOP) loading. Although some new infill walls show a good OOP performance, generally, they do not have the right economic justification or have complexity in construction. Therefore, in this paper, an innovative economical infill wall is presented that is not complicated in construction. The proposed wall constructed by light expanded clay aggregate in especial shape that reinforced with side plates, top, and bottom rebars. Experimental and numerical studies were carried out to investigate its seismic performance. Experimental results showed a high continuity between blocks of wall due to its especial... 

A significant part of torsional effects in buildings is due to disregarding the arrangement of infill walls during the design. This is a challenging issue since on the one hand the structural engineers do not usually consider infill walls in modeling a structure, while on the other hand the architects do not pay attention to the seismic behavior of infill walls during architectural design. In this research, an approximate method for identifying the torsion caused by infill walls was proposed to be used at the final stages of basic architectural design, which is based on the geometric specifications of architectural plans and does not require structural specifications. For this purpose,... 

The objective of the research is to determine the effect of friction stir processing (FSP) parameters and vibration on the machining behavior of AZ91 alloy. The article displays the state of the art of AZ91 alloy machinability including chip formation, chip morphology, and cutting forces. In this method, the vibration was applied to the process line through the fixture under the workpiece during the FSP. The three-dimensional finite element (FE) modeling was applied for simulating the small-hole drilling process of AZ91 alloy. The large deformation of work and the chip formation in drilling process is realized by incorporating Johnson-Cook material constitutive model and material failure... 

Torsion is one of the most important causes of building collapse during earthquakes. Sometimes, despite the symmetric form of the building, infill walls disturb the symmetry of the lateral resisting system. The purpose of this research is to investigate the effect of urban layout on developing torsion caused by infill walls. For this purpose, a typological study was conducted based on the conditions of perimeter walls on 364 buildings and then 9 cases were selected. The dimensions of the selected buildings are constant and the conditions of the perimeter walls including facades with openings and cantilevered facades are variable. The selected buildings with 60 different layouts of infill... 

Surface integrity is one of the important parameters affecting the quality and functionality of mechanical components. This paper presents an investigation on effect of drilling parameter on the surface integrity of Inconel 718 through a combination of experimental and simulation works. The machining responses that are determined through the experimental work include microhardness, microstructure changes, and surface roughness. The average grain size of the microstructure of the workpiece is estimated by using a simulation model. The experimental and simulation results show that higher spindle speed facilitates the formation of white layer near the machined surface and decreases the average... 

The influx of solid or liquid particles of drilling mud into the pores of rock or mud loss phenomenon and clay swelling can sometimes lead to severe productive formation damage and cause to wettability alterations of reservoir rock from hydrophilic to oleophilic. Therefore, designing an appropriate fluid that is compatible with formation fluids and could reduce reservoir damage and increase the productivity of wells is very important. The two main mechanisms of surfactants are reduction of the surface tension and wettability alteration of rock reservoir that are effective in taking the oil. Regarding the importance of the wettability in reservoir productivity, this article is aimed to study... 

The knowledge of the connectivity across the reservoir not only helps to find out the potential oil recovery within a particular well configuration but also affects on the other reservoir engineering decisions such as infill drilling. Connectivity also controls the swept fraction of the hydrocarbon in place in secondary displacement other than the recoverable rates of the hydrocarbon. Most of the time we need a fast estimation of connectivity for decision making during field development. Percolation theory is a very useful tool to get this goal. According to this fact that the results of this method are universal, they could be used widely. During this study a percolation model is developed... 

A thermo-mechanical finite element model is developed to accurately predict residual stresses of the multiple beads laser cladding process, incorporating the cyclic plasticity into the analysis by utilizing the nonlinear kinematic hardening behavior. Finite Element results are presented for Inconel 718, a material for which the laser cladding process is widely used. The FE results are compared with the results of incremental center hole drilling conducted on three specimens with different clad beads to evaluate the effect of cyclic plasticity modeling on the residual stresses. The results indicate that incorporating the nonlinear kinematic hardening model into the analysis can reduce the... 

Recently, Colloidal Gas Aphron (CGA) based fluids have been introduced to further develop depleted hydrocarbon reservoirs. This fluid system has been employed in an attempt to control drilling fluid invasion and, thus, reducing formation damage occurred during drilling operations. Understanding the mechanisms of fluid invasion control is of great importance for successful design and application of CGA-based fluids in drilling operations. Although fluid flow of conventional foams has been studied extensively in the available literature, little attention has been paid to CGA fluids flow, especially in heterogeneous fractured porous media. Here, an experimental study was conducted to achieve... 

There are many equations available in the literature using the results of CPT (cone penetration test) and SPT (standard penetration test) measurements to predict the end bearing capacity of drilled shafts in sand. However, there are few equations that use soil parameters, such as friction angle and elastic modulus, as input values. Also, these available equations usually overestimate the end bearing capacity, and at times show conflicting results with respect to the parameters they use. This paper describes a numerical procedure to overcome the above shortcomings. The results obtained in this study were compared with both experimental and numerical results available in the literature. A... 

There are many equations available in the literature using the results of CPT (cone penetration test) and SPT (standard penetration test) measurements to predict the end bearing capacity of drilled shafts in sand. However, there are few equations that use soil parameters, such as friction angle and elastic modulus, as input values. Also, these available equations usually overestimate the end bearing capacity, and at times show conflicting results with respect to the parameters they use. This paper describes a numerical procedure to overcome the above shortcomings. The results obtained in this study were compared with both experimental and numerical results available in the literature. A... 

Dynamic contact angle measurement; as a standard method for surface wettability analysis, is usually conducted through the analysis of sessile drops formed following the low rate injection of fluid from beneath through a drilled hole via an injection needle. However, understanding/characterizing the changes of drop contact angle from the point where the flat solid surface begins is not well discussed yet. Moreover, during the evaluation of size-dependent behavior of contact angle of millimeter-scale drops, the effect of the drilled hole is ignored. In this regard, in the current study, the experimental and thermodynamic characterizations of the sessile drop advancing contact angle...