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... 

Water injection, as one of the conventional methods to increase the oil recovery factor has always been at the center of research works for Enhanced Oil Recovery (EOR). The conducted studies show that by controlling the amount and type of ions in the injected water, the recovery efficiency can be improved. In the meantime, most of the investigations are focused on the interaction between water/rock/oil to trace the wettability alteration. However, these interactions especially between the injected water and the oil phase, would lead to change of surface charge distribution of the reservoir rock. Besides, this effect can change some of the characteristics of the fluid phases, especially in... 

The Oil wells are usually damaged because of the drilling process and production scenarios or fluid injection during EOR processes. These damages would critically affect the rate of production and injectivity of the well in the form of plugging damage. Different methods are used to fix these damages and increase the production flow from the oil wells. One of the most widely used well-stimulation methods to remediate this challenge is well acidizing. Although this method has very high efficiency in improving the ability of wells, if it is not designed and implemented correctly and optimally, it can cause induced damage and even lead to the well shutting. This challenge is especially reported... 

In order to investigate the effect of molecular-structural properties of asphaltene fraction on changes in wettability and flow of crude oil in the porous medium, four crude oil samples from oil fields in southern Iran were tested ;To know the characteristics of crude oil, molecular-structural properties of asphaltene fraction and the effect of asphaltene fraction on the wettability properties of surface, Experiments such as crude oil density and viscosity measurement, crude oil hydrocarbon analysis, asphaltene extraction with standard IP-143 method, elemental analysis and metal content, gel permeation chromatography, nuclear magnetic resonance, interaction between rock and asphaltene.... 

Prediction and prevention from asphaltene deposition is an essential topic in oil production systems that can enormously increase oil production costs. Many studies have been done to understand and predict the behavior of asphaltene-containing oils. Prediction and investigation of asphaltene precipitation are required to predict the asphaltene deposition problem. Changes in temperature, pressure, and composition can cause precipitation, and these changes are inevitable during production. This dissertation compares the thermodynamic models that can simulate asphaltene precipitation. Firstly, A comprehensive review was done to extract the maximum amount of experimental data from the literature... 

Efforts to identify, predict, and resolve problems linked to asphaltenes and flow assurance have resulted in the development of numerous laboratory and modelling techniques. However, there has been little research on the molecular structure of asphaltenes and how it relates to solubility, stability, aggregation, and deposition behavior. Not only was a thorough structural analysis of asphaltene extracted from three samples of light, medium, and heavy oil performed in this study, but medium oil asphaltene was also fractionated into three sub-fractions based on solubility, with minimum, medium, and maximum solubility, and each subfraction was subjected to a structural analysis. All asphaltene... 

During the production of crude oil from reservoirs, the production of quantities of formation water along with this oil, causes the crude oil does not have the necessary indicators for transportation, refining and ultimately export. The presence of water and salt along with crude oil causes corrosion of refinery and transmission equipment and makes oil unfavorable in terms of economic efficiency (both for domestic use and for export). water and salt produce stable emulsion with oil that can be stable for a long time and can not be easily separated from crude oil. Therefore, separation of water and salt from crude oil is one of the most important issues in the oil industry. Breaking this... 

In this study, for investigation of water salinity effect on asphaltene modeling, PC-SAFT equation of state has been used. All steps of modeling have been done by C sharp programming language software. Nghiem model has been used for modeling of asphalting pure solid. In this model, the heaviest component is split into two precipitating and nonprecipitation parts that their physical properties are the same in each part. Furthermore, to determine the exact mechanism of asphaltene precipitation, an oil model (Asphaltene+heptan+tuloene) in the presence of different water brine such as synthetic brine (with MgCl2, CaCl2, and Na2SO4 salts), seawater) ten and two times diluted), and formation water... 

The study of low-salinity water flooding or smart water flooding as secondary or tertiary oil recovery methods started in 1960 and many researchers have studied the effect of ions types on asphaltene precipitation/deposition during the injecting water into the oil reservoirs. To reduce the asphaltene challenges, one needs to properly investigate this phenomenon and better understanding of the cause of precipitation. It is already known that the amount of asphaltene deposition can be reduced by controlling the deposition criteria. For example, water microemulsion in the oil phase would cause the asphaltenes to be adsorbed on the water oil interface by hydrogen bonds due to heteroatom... 

Crude oil production could cause the thermodynamic equilibrium of the crude oil to be disturbed in the well column which results in asphaltene precipitation and deposition. The thickness of the deposited material grows over time until it completely blocks the well column.Due to the hard and insoluble nature of deposited asphaltene, the two main chemical and mechanical methods are found to be more effective. It should be noted that the actual organic sediments in the piping are not pure and consist of three components: asphaltene, resin and paraffin. Therefore, it is very important to know the composition of the deposited material before selecting the appropriate chemical solvent.The samples... 

Asphaltene deposition, the heaviest and most polar component of crude oil, which causes great economic damage inside the reservoir, near wells, pipelines and well equipment, is an important challenge in the production of oil reservoirs. The main purpose of this study is to prob the adsorption kinetics and the mechanism of asphaltene adsorption on the metal surface by a quartz crystal microbalance device under different conditions of temperature, flow rate and degree of asphaltene instability. In this study, indirect uv-vis spectroscopic method was used to determine the onset of asphaltene precipitation, then experiments were designed using Taguchi method. A new QCM device has been designed... 

Asphaltenes are a polydisperse mixture of the heaviest and most polarizable fractions of the crude oil. They are defined according to their solubility properties as being soluble in aromatic solvents but insoluble in light paraffin solvents. Asphaltenes are usually responsible for many problems like wettability changes of the reservoir rock, pore clogging in the reservoir porous matrix and fouling in wellbore tubing and production surface facilities. Most of the studies in the literature, addressing the asphaltene precipitation and deposition (APD), are investigating natural depletion or gas injection process such as CO2 flooding. These studies show that asphaltene deposition and... 

Formation, precipitation and deposition of heavy organic compounds of petroleum fluids including, but not limited to, asphaltene in oil reservoirs and production systems have been by far the most important and challenging flow assurance problems. Therefore, preventative actions to control organic deposits in oil formations and production systems which can lead inevitably to reduction or cessation in production, have always been a main challenge for oil producers.In this thesis, a one dimensional simulator have been developed to study asphaltene precipitation, aggregation and deposition in an oil well column at isothermal and non-isothermal conditions. While the previously proposed PC-SAFT... 

Asphaltene deposition, considered as the heaviest and the most polarizable fraction of crude oil, can cause severe problems in oil production and extraction systems. Oil production companies annually bear huge reduction or even cessation in production and, in turn, costs due to asphaltene precipitation and deposition in wellbore or production tubings. To gain more and better insight into asphaltene formation in production systems, the conceptual investigation on the mechanisms of asphaltene adsorption and deposition on a solid surface is indispensable. In this study Asphaltene's particle adsorption and deposition onto the metal surface under the effect of flow is investigated by experimental... 

Wax precipitation may occur in production or transportation of crude oil form field which is a serious problem in petroleum industry. Flow assurance issues concerning wax precipitation make it necessary to develop a precise thermodynamic model to predict the wax appearance temperature and amount of precipitation at different conditions. In this work a new procedure has been proposed to characterize crude oil based on the SARA test considering the wax and asphaltene as single pseudo components. Two scenarios have been investigated for the survey of the crude oil characterization, with and without asphaltene pseudo component. Also, in this work, the Perturbed ... 

Given the decreasing trend of light petroleum reserves and the necessity to produce heavy and extra-heavy oil resources, the challenge of dealing with existing asphaltene related problems, which is the heaviest and the most complex component of crude oil, has become increasingly tangible. Asphaltene precipitates and deposits due to pressure, temperature or composition alterations which leads to obstruction of porous media and production facilities. Set the costly methods aside, one of the available approaches to prevent asphaltene precipitation, is to apply an electric field upon the suspected zone, which is cheap and uncomplicated. Besides, utilizing nano-particles while applying electric... 

In this thesis, by focusing on the hydraulics of three phase flow in vertical tubing to investigate asphaltene deposition problem, the solid particles behaviors in a turbulent flow is fully studied. Reasonable size distribution for particles (based on previous works and researches) was assumed and a model for 2 sections of a Marrat oil field well to evaluate their asphaltene deposition problem was developed. Three phase liquid-gas-solid flow in the well tubing was simulated. Asphaltene deposition profile on the well tubing, mean and maximum of the deposition rate and particle concentrations in the flow regime were calculated and compared with real field data. Better agreement with field data... 

The aim of this project was to upgrade and reduce viscosity of heavy oils by adsorbing of asphaltene on Ni-Mo/CB and converting it into lighter and more valuable gas and liquid compounds. Asphaltene has been extracted from a heavy crude oil sample of Soroush oil field in Iran. After adsorption, Asphaltene conversion to lighter components (gas/liquid) was studied through hydrocracking process. To prepare the support of catalyst, Carbon Black, initially a thermal treatment step under the argon gas atmosphere followed by acid-washing process was performed. Afterward, the catalysts was prepared through dry impregnation method. In order to activate catalyst for hydrocracking, the catalysts has... 

Asphaltene precipitation and deposition are sources of a number of problems for petroleum industry. Thus, solving the problem of precipitation and deposition is very important. In order to measure deposition level, study of other asphaltene flocculation is vital; since there is a time interval between precipitation and deposition. Use of chemical inhibitors is one of the best methods for prevention of asphaltene precipitation that could postpone precipitation point and prevent formation of huge flocculations. In this study, effects of asphaltene flocculation size on deposition with or without using inhibitors were investigated. In this regard, QCM was used for measuring the amount of... 

Formation damage is probable to occur while drilling, work-over operations, and well completion in near wellbore zone due to different reasons; which leads to excess pressure drop through this area. Well stimulation operations are proposed to remove these damages and improve oil production; among which, acidizing is known as a traditional applicable method to stimulate oil and gas wells. Although this approach is accepted and chosen as a well stimulation method to remove formation damages, its poor design and implementation results in new formation damages. One of these arises when acid contacts asphaltic oil, which causes asphaltene particle instability and asphaltic sludge rapid...