Sharif Digital Repository

Surfactants are widely used in enhancing oil recovery. But application of worm-like micelles which seem to be a perfect candidate for enhancing heavy oil recovery have been less studied despite their significant ability in reducing interfacial tension and their high viscosity. This research consists of three parts. In the first part, the kinetic and equilibrium adsorption of surfactant on reservoir rock is experimentally investigated, and its appropriate kinetic and equilibrium adsorption model is specified. According to the adsorption models, the pseudo second order kintic coefficient of adsorption is proved to have a linear relationship with concentration, so its value at different... 

In this study, aqueous two-phase systems (ATPS) containing Tween 20 as a biocompatible nonionic surfactant and three different salts (NH4HPO4, NH4CH3COO and Mg(CH3COO)2 ) were prepared and their extractive potential for Lysozyme enzyme was evaluated. These systems have surfactant-rich top phase and salt-rich bottom phase. Phase equilibrium diagrams at 23 ° C were obtained by using the cloud point method and the results were successfully fitted to the Merchuk correlation and their trends were correlated with the effective excluded volume (EEV) parameter. Afterward, the partitioning behavior of the lysozyme and its extraction efficiency in the systems of Tween 20/diammonium hydrogen phosphate,... 

A biocompatible ferrofluid have been prepared by co-precipitation of FeCl2.4H2O and FeCl3.6H2O under ultrasonic irradiation and with NaOH as alkaline agent. Also cystein was used as capping agent in the solution. Magnetic properties of the produced ferrofluid then determined by VSM test and magnetite nanoparticles were characterized by XRD and TEM techniques. Results indicate the presence of a biocompatible superparamagnetic ferrofluid including magnetite nanoparticles with particle size ranging under 15 nm. The effect of ultrasonic irradiation on presence of a sharp particle size distribution then denoted by comparing the condition with production without ultrasonic irradiation  

Solvent-solvent and solute-solvent interactions were investigated in mixtures of Triton X-100 with water, methanol, ethanol, 1-propanol, tetrahydrofuran and butyl acetate. Solvatochromic parameters, including normalized polarity (E_T^N), dipolarity-polarizability (), hydrogen-bond donar (), and hydrogen-bond acceptor () abilities, were determined in these mixtures. We observed similar behavior for E_T^N and  in TX-100/alcohols mixtures. Parameters confirmed the preferential solvation in mixtures of surfactant and solvents.
Experimental data were handled in preferential solvation model. Six binary systems exhibit a complex behavior for all three indicators. It was shown that... 

One of the most well-established methods of increasing oil production rate from existing fields is infill drilling. However, drilling these depleted reservoirs with conventional high density drilling fluids may cause formationdamage problems and subsequently reduce the expected production rate. To overcome these technical problems, the use of lightweight aphron based fluids isincreasing rapidly in the petroleum industry. Rheological and fluid loss performance of aphron based drilling fluids can be improved in the presence of nanoparticles; however, very limited information is available in this field. Moreover, a thorough knowledge about the hydrodynamic flow behavior of drilling fluids... 

Always, understanding the properties of crude oil and related phenomena of that has been noticeable matter. Surface tension is one of the important fluid properties and the evaluation of that is essential in oil industry especially in enhanced oil recovery method (EOR) and transport of crude oil by using emulsions.
In this research, interfacial tension (IFT) was measured via pendant drop method. The effect of three parameters was investigated on IFT for creating of stable oil/water emulsion. These parameters were temperature, concentration of surfactants, and salinity. They were varied between 25-65 ᵒC, 0.05-0.2 gr and 5000ppm respectively. It was used two types of surfactant; acid... 

Understanding the properties of crude oil and the phenomena arising from this precious matter has always been of considerable importance. One of these important phenomena is emulsion, which is well-known in a great number of crude oil-related processes such as drilling, well completion, production, transportation and even the processing units in the refinery. One of the most important properties of crude oils and their emulsions is their flow or in other words their rheology. Therefore, in this project has also been tried to investigate the rheological behavior of crude oil and water in crude oil emulsion, experimentally and theoretically. The experiments were carried out using two crude... 

Surfactants are materials that reduces surface tension, and this property has provided a wide range of applications for them. Most of the surfactants reduce surface tensions at the interface of two fluids. The pharmaceutical and food industries, detergents, cosmetics, agricultural pesticides, dye production and oil extraction are among these applications.In this study, the formation of droplets in the presence of three types of surfactants SDS, CTAB and Tween 20 has been investigated. To evaluate the droplet behavior in the presence of specific surfactants, various parameters such as formation time of the droplet, the diameter and length of the droplet formed, the diameter and length of the... 

Nowadays, due to limitation of production from conventional oil reservoirs, enhanced recovery from heavy oil reservoirs are of great concern. In heavy oil reservoirs, only 5% of initial oil in place (IOIP) is producible due to high viscosity. Water flooding increases oil recovery just up to 10% which is due to improper mobility ratio. One of popular methods for increasing oil recovery is injection of chemical materials. Chemical methods are used in reservoirs that have high degree of heterogeneity like heterogeneous and layered reservoirs. These heterogeneities cause diversion and loss of injected water which leads to remaining of oil in its place. Using surface active agents, as a popular... 

Heavy oil reservoirs include a major part of the world’s oil reservoirs. Therefore consideration to their enhanced oil recovery (EOR) aspects has a great importance. In heavy oil reservoirs secondary and tertiary EOR methods, have an insignificant effect on oil recovery and so we’d better to use chemical methods to improve mobility and oil recovery. One of the appropriate EOR methods which has attracted a lot of attention is alkaline – surfactant – polymer (ASP) flooding which has a considerable impact on EOR from heavy oil reservoirs. In this EOR method, the low concentration of surfactant in the injecting fluid, results in a low or ultra-low interfacial tension (IFT) between residual oil... 

Heavy oil reservoirs contain huge amount of initial oil in place in the world. Thus, enhancement of their production attracts lots of attention. Primary and secondary oil recovery methods have just little effects on the production of these reservoirs, thus, using innovative chemical methods which lead them to increase their mobility is recommended to improve their oil recovery efficiency. One of these proper and novel methods which has been established recently to enhance oil recovery is ASP1 flooding that can significantly increase oil recovery from petroleum heavy oil reservoirs. In addition, considerable numbers of reservoirs especially heavy oil reservoirs are fractured reservoirs. In... 

Today, due to limited number of light oil reservoirs, enhanced recovery from heavy oil reservoirs is taken into consideration. During the early production from heavy oil reservoirs, due to high viscosity, only a small amount (about 5%) of the oil can be produced; also after water injection operation due to unfavorable mobility ratio of water and oil, sorely more than about 10% of the original oil can be produced. On the other hand, fractured reservoirs represent about 20% of the world's oil reserves, while over 60% of the world's remaining oil reserves are in fractured reservoirs. Water flooding process leaves very high amounts of oil as remaining oil in these reservoirs too. One of the... 

Foam injection for enhanced oil recovery is concerned by petroleum engineers because it decreases adverse effects of fingering and gravity segregation caused by the injected fluid .Obviously foam stability is an important factor in the efficiency of this process. So investigating it is an imperative. One of the ways that less studied and can improve foam stability is using of nanoparticles. In this project effect of nanoparticles on foam stability and displacement mechanism during foam flooding has been discussed.
Study consisted of two sets of experiments. In the first part, the static foam stability in the presence of silica nanoparticles has been investigated. Also influence of... 

Using foam for reducing undesirable effects of fingering and gravity segregation in enhanced oil recovery through gas injection has attracted a rapidly increasing interest in recent years. Lack of stability of foam often limits its application. However there is a lack of systematic study of effects of unmodified and in-situ modified silica nano-particle on foam stability and foam behavior in the presence and absence of oil and also polymer effects from the prospective of analysis of foam dynamic stability, size of foam bubbles, and foam flow behavior in Hele – Shaw cell. Main objectives of this study are mechanistic investigation of effects of polymer – surfactant systems and in-situ... 

One of the suitable methods in EOR processes is miscible and immiscible gas injection. By gas injection, it is possible to replace all the oil, which is in contact with the gas. However, reservoir heterogeneity, low density, and low viscosity of gas result in problems such as gravity segregation, and fingering and consequently the gas reach the production well without any significant contact with reservoir oil. A way to deal with this problem is gas injection in the form of foam. In fact, gas injection in this manner increases the oil production by decreasing gas mobility and the negative effects of reservoir heterogeneity on gas displacement. Foam stability has a key role on the efficiency... 

Nowadays, due to limitation of production from conventional oil reservoirs, enhanced recovery from heavy oil reservoirs is of great concern. However, production from these energy resources is not a simple task and production using common technologies is not easily exploitable. Heterogeneous structure and also high surface tension between injected fluid and reservoir oil are of the main challenges during water flooding processes in heavy oil reservoirs. The high surface tension force causes a large part of the oil remains in the reservoir after the water flooding operation. One method for overcoming this problem is the use of surfactants that reduces capillary forces and consequently... 

Chemical flooding such as surfactant flooding in oil reservoirs can change the wettability and interfacial tension between oil and water and so reduce the residual oil saturation in the reservoir. Some of these materials can be adsorbed a lot on the surface of carbonate rocks, so it is difficult to predict the oil recovery factor in such process. Therefore it is necessary to survey the adsorption amount of surfactants in chemical EOR injections.In this thesis, the adsorption of a nonionic surfactant on the surface of carbonate rock is experimented and the proper model is obtained. Then the surfactant is injected in a core saturated with oil to observe the efficiency of this surfactant in... 

There are considerable investigations on wettability alteration in carbonate reservoirs in recent years. The presence of ions including Ca, Si, Al etc in natural carbonate rocks and also the presence of various fatty acids, resins, asphaltenes etc in crude oil makes it difficult to understand the complex mechanism of wettability alteration by using surfactants. Furthermore there is still a conspicuous lack of dynamic wettability alteration model to demonstrate the dynamic behavior of cationic surfactants during wettability alteration. It is also widely accepted that cationic surfactants have substantial impact on changing the wettability of strongly oil-wet matrixes to a more water-wet... 

One of the most important EOR methods in oil reservoirs is surfactant and polymer flooding. Surfactants cause decreasing in interfacial tension between oleic and aqueous phases. However, polymers give us efficient mobility control in displacing oil by increasing the viscosity of aqueous phase. Therefore, oil is displaced in aqueous phase by viscous forces.
One of the most important challenges in surfactant flooding is adsorption. The net surface charge distributed on the rock surface depends strongly on pH. When we inject surfactant in reservoir, electrostatic charge on rock surface causes the first-layer adsorption. After that we have had second-layer adsorption.
In this thesis we... 

Recent studies have shown that the injection of low-salinity water would enhance the oil recovery factor for both the core scale and the field test. The evidence obtained from laboratory studies showed that the control of salinity and the composition of injected water has successfully affected the oil release, hence enhancing the oil recovery efficiency. In this method, by changing the type and amount of dissolved ions in the injected water, the water/oil/rock interactions are altered. Based on this, extensive studies have been focused on the mechanisms for the trapped oil release at the pore scale. Several mechanisms have been proposed to explain this phenomenon, which can be divided...