Sharif Digital Repository

One of the main problems associated with the oil production is asphaltene precipitate in the reservoirs. In order to plan for the EOR methods, production scenario, and selection of completion technology, it is necessary to study the initiation of asphaltene precipitation called onset. Since the experimental methods is not only is so expensive and time consuming, the required materials are not available. Consequently, modeling approaches as new methods are proper substitutes for laboratory procedure. These methods need less costs and time and higher accuracy compared to the experimental investigations which are the advantages of these methods. Computational operations for onset determination... 

Detetrmination of particulate matter (PM), as one of the most important pollutants in big cities, requires extensive system of monitoring stations. Remotely sensed atmospheric data due to their large spatial coverage and frequent observations are emerging as an important addition to conventional ground based atmospheric monitoring. In this regards this study presents an approach to analyze the relationship between PM10 (particles with aerodynamic diameter less than 10 μm) and the satellite product of aresol optical depth (AOD), which is the measurement of the extinction of light due to interferences with particulate matter. In the current study AOD is observed by Moderate Resolution Imaging... 

Intelligent control or management of well or reservoir is a method which is used in order to optimize the production for increasing recovery factor so that the minimum damage or reduction of pressure occurs during production lifetime. Azar oilfield has 17 wells and the production from this field isn't started. Thereupon designing a suitable well completion model and a control algorithm to optimize the production for the first two years of production is necessary and indispensable. For this purpose, by collecting basic information and their analysis (for example pressure, temperature, production rate, the type and amount of produced fluids), designing of downhole installations and modeling... 

A prey-predator fishery model with stage structure for prey is discusing in this thises. The adult preyand predator populations are harvested in the proposed system. The dynamic behavior of the model system is discussed. It is observed that singularity induced bifurcation phenomena is appeared when variation of the economic interest of harvesting is taken into account. We have incorporated state feedback controller to stabilize the model system in the case of positive economic interest. Fishing effort used to harvest the adult prey and predator population is used as a control to develop a dynamic framework to investigate the optimal utilization of the resource. Simulation results show that the... 

In this thesis we have investigated and improved the signal processing techniques which are used for monitoring the heart abnormalities in terms of ECG (ElectroCardioGram) signals in order to detect heart attacks before they occur. De-noising ECG signals are one of the most important research topics in computer and electrical engineering fields. There are many different algorithms for de-noising signals in various domains. It usually is needed to propose a suitable algorithm for each specific system. In some cases instead of developing a new algorithm, we could modify the available ones for de-noising in our system. ECG signals are output from an electrocardiograph which measures electrical... 

Water base drilling fluids are the most common drilling fluids in oil and gas operations and biopolymers are the requisite additives used in such kind of fluids frequently. Unfortunately, at harsh conditions of HPHT the polymers undergo thermal degradation which cause serious loss in fluid rheological and filtration properties. Accordingly, this will induce operational pitfalls and tremendous cost. The power of economy along with environmental regulations force us to search for reasonable chemically benign additives to fulfill this need. Nanoparticles are the most promising additives proposed in this study to address this challenge. Regarding their unique exclusive properties, they are able... 

The increasing demand for energy forced to production of oil as one of the main sources of energy. Along with the increase in oil production, the proportion of water produced with oil is increasing relative to the oil produced. On the other hand, environmental restrictions for the discharge of industrial effluents into the environment are becoming more and more stringent every day. Before discharging the effluent into the environment, petroleum must be removed. The complexity of these issues demonstrates the need to develop new technologies and improve the efficiency of existing technologies. Gas flotation are among the technologies adopted in the field that have been used throughout the... 

Openings and development of subway system have occurred since 1998 in Tehran, and 115 stations have been constructed from then until 2019. This could have various effects on urban characteristics and passenger behaviors, which air pollution could be one of the consequences. In this research, we want to investigate it`s effect on Tehran air pollution as well as heterogenous effects on different distances. For this, we use air pollution data of monitoring stations and meteorological data as well as location and construction time of metro stations. We use difference in difference and OLS regressions to estimate these causal effects. We see that air pollution has been decreased 2-3% as a result... 

In the recent years, there has been an increasing attention toward usage of ultrasonic for enhanced oil recovery practices. But, thorough knowledge of active mechanisms and spreading and characterization of developed fingers during this practice is not available. From the other hand, due to limited amount of light oil fields, more attentions towards recovery from heavy oils is the need of the hour. Documents show that the big issues during the enhanced oil recovery from heavy crudes are high density of reservoir oil as well as poor development of fingers during injection due to high mobility ratios. In this study, results of ultrasound effect on the heavy oil recovery and its effect on the...