Sharif Digital Repository

Naturally fractured oil reservoirs represent over 20% of the world's oil reserves, while over 60% of the world’s remaining oil lies trapped in fractured reservoirs. However, relatively little success has been achieved in increasing oil production from these complex reservoirs. Water flooding process leaves much oil in the reservoir, especially in fractured reservoirs. Surfactant flooding is known to lower the interfacial tension and hence, reduces capillary forces responsible for trapping oil and increasing recovery. However, fundamental understanding how the fracture geometrical properties affect the oil recovery efficiency during surfactant flooding remains a topic of debate in the... 

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... 

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... 

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... 

Application of nanotechnology in the field of heat transfer has increased recently. The need to increase heat transfer rate yet decrease the size of cooling equipment, brought about lots of attention to thermal properties of Nanofluids. Nanofluid is the suspension of nanometer-sized solid particles in base liquid. Research on convective heat transfer of nanofluids which is only two decades old, shows great potential in increasing heat transfer rate. Although there is a remarkable research on thermal conductivity of Nanofluids, negligible research was conducted on combined Nanofluids . Developed Theory for thermal conductivity of combined nanofluid can be used to modeling the thermal... 

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... 

The aim of this research is to study the effect of surfactant type and the concentration reactants on the size, shape and magnetic properties of iron-gold core-shell magnetic nanoparticles (NPs) useable for biomedical application. The reverse micelle procedure was employed to synthesize iron NPs using two surfactants of CTAB and SDS. A gold shell with a thickness in the range of 10 to 40 nm was induced by reverse micelle method in order to prevent oxidation of the iron core. The size and morphology of NPs were studied by transition electron microscopy (TEM). It was found that the size of NPs increases by the increasing the reactants concentration while the morphology of the NPs was not... 

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... 

In the modern societies, wastewater treatment is essential in achieving high level of standard in environmental protection and disposal. Recently, many researches are performed to study the surfactants’ biological decomposition in wastewater treatment process. In this project, fixed bed aerobic reactors are used in order to remove surfactant from wastewater. Integrated fixed film activation sludge reactor (IFAS) is used to remove surfactants and organic matters. It also used to study the capability of micro organisms in organic load removal in fixed bed biofilm for biological treatment of industrial wastewater. Pumice stone were used as the support in the reactor. The pumice stone is a... 

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... 

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... 

Surface phenomena is one of the fundamental branches of science that has many applications in industries related to multiphase processes. One of the most important issues of this knowledge is inter-phase transport phenomena in contacting gas - liquid and liquid – liquid systems. Multiphase systems generally include dispersions such that in many cases are associated with the relative motion between the continuous and dispersed phase. One of the most widely used inter-phase flow systems is dispersion of gas bubbles in the bulk of liquid. The overall efficiency of these systems is often determined by the characteristics of the gas phase. In order to understand the dynamic behavior of such... 

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... 

Matrix acidizing operation is one of the popular methods of well stimulation in the oil and gas industry which is used to remove near wellbore damage, increase the permeability, hence improve the production rate from the formation. Hydrochloric acid is used in the carbonate reservoirs to remove formation damage and create wormhole deep in the rock. It has been shown that with the proper operating design, significant improvement in the production rate can be obtained. A successful acid operations involves the proper selection of the candidate wells, identify the type of formation damage, stimulation method selection, correct design acidizing scenario, implementation of the technique and... 

In this experimental work terminal velocity, velocity profile and aspect ratio of bubble with 1.49 mm diameter which ascend in pure water and infected by surfactant nonionic C10DMPO and surfactant ionic SDS in regime that surface tension is dominant, have been considered. Observations showed that with respect to entering nozzle, bubbles with this diameter have two initial stable shape; spherical and extended form on surface for horizontal needle and vertical nozzle. Results are (1) Bubbles with initial spherical shape had lower terminal velocity and higher aspect ratio with respect to bubbles with initial extended form, (2) Spherical bubble had aspect ratio about 1 at whole bubble column... 

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... 

In the past years, upstream processes have been receiving a considerable R&D investment and commercial attention. The downstream processes have, however, been overlooked causing a production bottleneck that is shifting the costs of production from up to downstream. The need to develop more efficient and cost-effective separation and purification processes is, thus, crucial in order to improve process efficiency and economics keeping the required high standards of quality for market approval. In this research, promising aqueous two-phase systems (ATPS) containing Tween 20 as a quite biocompatible non-ionic surfactant and different salts (K3Citrate and NaH2PO4) were prepared and their... 

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,... 

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 purpose of this research is producing one phase silica superhydrophobic coating by sol-gel method and drying temperature less than 200 degrees. For preparing micrometer and nanometer scaled hierarchical structure based on silica, TEOS precursor and Fumed Silica nanoparticles were used by density of 43/30 cc/lit and 6/52 gr/lit in order to provide desired roughness in the range of 40 nm. Moreover, HMDS surface modifying agent was used for reducing the surface energy of coating, which is not a danger to the environment in comparison to the same substances. The best Contact Angle is 155 degree and the best Sliding Angle is less than 5 degree. For instance, it was created with the...