Sharif Digital Repository

Fractured reservoirs are important due to having a significant volume of oil and gas in Iran and the world. With passing half of the life of Iran's reservoirs, we see pressure drop and decreasing in production rate at them. For this purpose, the maximum production of this type of reservoirs requires using methods of enhanced recovery. Among these methods, water-flooding method is one of the most common and widely used methods, which is effective in increasing the recovery rate of the reservoir. Studies in this field are divided into two parts: laboratory and simulation. Although the enhanced recovery methods are carried out at the field scale, the fluid movement mechanisms inside the... 

Severe plastic deformation (SPD) processes, in addition to increasing the strength of alloys, reduce their ductility. Aluminum alloy 2024 in the initial annealing state (420°C, 150 minutes) is failed after 5 passes if subjected to the multi-directional forging (MDF) process at room temperature. Therefore, in this project, with initial effective strains of 1 and 2, intermediate annealing was used at temperatures of 150°C, 250°C and 350°C (20 minutes) between process passes. This not only maintains the major strength created in this alloy after the initial passes but also provides the capability of applying more passes in this process. After each step, the microstructural examination was... 

The production of oil is challenging in the fractured reservoirs due to the large transmissibility contrast between matrix and fracture, and primary recovery is often low. The recovery efficiency depends on the relationship between the fracture and matrix permeability, and is strongly dependent on the wettability of the matrix, which reflects the imbibition potential of the reservoir. Among these parameters the multiphase fluid flow in gas invaded zone is the point of interest in this project. Gas injection in naturally fractured reservoirs maintains the reservoir pressure, and increases oil recovery primarily by gravity drainage and to a lesser extent by mass transfer between the flowing... 

Fracture reservoirs are highly heterogeneous. This heterogeneity makes the process of adjusting model parameters to match both the static geological and dynamic production data challenging. For this reason, the characterization of the fracture network of these reservoirs, which is achieved by finding the appropriate probability distributions of the fracture properties in the discrete fracture network model, requires the use of an integrated workflow for the process of history-matching.This thesis, presents an integrated workflow for the process of history-matching of naturally fractured reservoirs with field-scale performance capability. In this methodology, first, multiple discrete fracture... 

This thesis represents the obstacle avoidance of a fixed-wing small aircraft using optical flow information of cameras mounted on the aircraft. The thesis consists of two main sections. In section one, the ideal optical flow has been simulated based on the camera model, complete six DOF of flight equations, and the geometry of the environment. An analytical formula has been derived to relate the obstacle detection distance to the maneuverability of the aircraft. Having the obstacle detection distance, the control and navigation algorithms have been developed to achieve a collision-free flight for the aircraft in urban canyons and junctions. The effect of some parameters such as approach... 

Nowadays, one of the most important challenges in the design of digital circuits is their susceptibility to the strike of high energy particles which leads to the Single Event Transient (SET) and Multiple Event Transients (MET). In fact, technology scaling which results in lower supply voltage, higher operating frequency, and lower nodal capacitance, makes today’s digital circuits more susceptible not only to high energy particles but also to low energy particles. Moreover emerging deep sub-micron technologies and the integration of more cells in today’s chips have caused higher probability of MET occurrences. A lot of research has tried to reduce the soft error rate due to high energy... 

In the early time of the discovery of the quantum mechanics and some decades after that, various interpretations of quantum mechanics were proposed. However, many years after that, the “indetermenistic” perspective well-known for Copenhagen perspective which was proposed mostly by Bohr and his colleagues became the dominant attitude among physicists. But nearly two decades after the fixation point of the Copenhagen perspective, a new interpretation of quantum mechanics was proposed by Bohm which was nonlocal but deterministic and it could reproduce all the predictions of quantum mechanics.Bohm’s theory responded to the many theoretical and philosophical objections assumed to the Copenhagen...