Sharif Digital Repository

In this study, the effect of molybdenum disulfide nanosheets on the rheological behavior of suspensions was investigated using a polyethylene glycol matrix and glass grain fillers with a particle distribution of 60 to 103 microns. Crude molybdenum disulfide was obtained by single-layer and multilayered molybdenum disulfide nanosheets with thicknesses between 50 and 100 nm using acid, oxidation and heat shock methods. This claim was verified by various tests such as FT-IR, FESEM,EDS, TEM, DLS, XRD and so on. Subsequently, using 10 to 40% volumetric glass beads were prepared from the sample matrix. Stirring and ultrasonic, rheological behavior of these suspensions were investigated using... 

Wax precipitation is one of the major problems in the transfer of crude oil from field production to refineries. This wax with asphaltene compounds and some water and solids, closes the oil pipeline. One of the ways to reduce the amount of wax in pipes is to use additives (flow improvers) to crude oil and improve its rheological behavior. In this research, Five Iranian crude oils were characterized with SARA test and then the effects of various additives including ethylene vinyl acetate (EVA) in concentrations of 500 and 1500 ppm, alkyl phenol ormaldehyde resins (NPFR) with 1500 ppm and styrene-(ethylene-cobutylene)- styrene (SEBS) with 1500 ppm on viscosity, wax appearance temperature... 

Among chemically enhanced oil recovery (CEOR) methods, polymer flooding has the highest commercial potential. However, the most widely used conventional polymers such as partially hydrolyzed polyacrylamide (HPAM) are not applicable for high-temperature and high-salinity reservoirs. To overcome above-mentioned problems, in this work, a series of water-soluble hydrophobically modified polymers (HMPs) nanostructures comprising 2-vinyl naphthalene (hydrophobic monomer) has been produced by freestyle method (without Surfactant), micellar (with Surfactant). The size of the particles was investigated using scanning electron microscopy (FE-SEM) and optical scattering (DLS). Results from FT-IR... 

In this research, the optimization of culture medium and process conditions for the production of alkaline protease enzyme from Bacillus subtilis ATCC6633 strain for use in the detergent industry has been discussed. Among all the conditions affecting the growth and production of enzymes, the stirrer cycle in the fermenter, which causes different shear rates and is one of the most important factors in the amount of mixing and aeration, was chosen for further study. At first, the results obtained from the incubator shaker were carefully examined, and then different checks were made to adjust the fermenter stirrer speed through diagrams in three flow states: 1-laminar, 2-transitional, and... 

This study investigated the effect of oxidized molybdenum disulfide (MoS2) nanosheets on the anti-corrosion and rheological properties of epoxy resin. Raw MoS2 sheets were obtained as layered nanosheets with a thickness of 50 to 100 nm using acid washing, oxidation, and heat shock methods. The use of nanoparticle characterization tests such as XRD, FT-IR, FE-SEM, EDS, and TGA supports this claim. Then, in the next step, epoxy coatings containing different percentages (0, 0.3, 0.5, 0.8, and 1.5 wt%) of MoS2 nanosheets were prepared with polyamide hardener to investigate the effect of adding nanosheets and the optimal percentage. The best effect on the corrosion properties of the coating in a... 

The methods of Enhanced Oil Recovery (EOR) from reservoirs have been taken into consideration recently due to the decline in oil reserves and the rise in energy demand. Studies and investigations indicate the tremendous potential of chemical approaches based on injecting ionic liquids into the porous media with the goal of improving oil recovery. Additionally, hydrogels and polymers, which are two of the process' primary materials, are thought to be good alternatives. In the current study, a hydrogel based on carboxymethyl cellulose was first created and synthesized. Ionic liquids based on imidazolium and triflate anion were then added, and their effectiveness in enhancing the properties... 

Among the plastics produced around the world, polyolefins are the most used in human daily life and make up about two-thirds of the plastics produced in the world. Also, the most plastic waste is related to polyolefins, which are non-biodegradable plastics. One of the things that have challenged the recycling of polyolefins by traditional methods such as mechanical recycling is the loss of mechanical and rheological properties as well as their degradation. One of the methods of improving properties and postponing degradation is the use of vitrimerization reactions, as a result of which, in thermoplastics, a compatible covalent network is created, which gives the plastic the ability to behave... 

With a surge in consumption of modified binders in recent years, different methods have been used to evaluate the properties of modified binders with relative success. None of these methods are able to fulfill all the requirements for evaluation and intrerpretation of the physical, chemical and rheologocal properties of modified binders. Since rheological master curves can present a mechanical interpretation of the binders in a wide range of times and temperatures, in conjunction with other evaluation metheods, they are considered a promising means of evaluating the suitability of modified bindrers. The available master curve models do not possess the sufficient diversity for this purpose.... 

Nowadays, foaming agents have wide applications in drilling, cementing, fracturing and oil displacement in the petroleum industry. Typical applications are to make light fluids for drilling operations in naturally fractured reservoirs where lost circulation is a problem. Compared with conventional and aerated drilling fluids, foamy mud is a compressible and relatively homogeneous mixture. A great flexibility for pressure control is thus possible. In this study, a new foaming agent of Yas-Khorramshahr Company is introduced to drilling fluids. Stability of this agent at different concentration and in presence of Salt and crude oil is tested. Also common drilling muds are lightened and... 

The rheology of oil well cement (OWC) slurries is generally more complicated than that of conventional cement paste. In order to contend with bottom hole conditions, a number of additives are usually used in the OWC slurries. The objective of this research is to develop a fundamental understanding of the important mechanisms that affect the properties of OWC slurry such as rheological properties, free water, compressive strength and thickening time incorporating various chemical and mineral admixtures. The partial replacement of OWC using different nanoparticle weight percent has been proved to be a promising method. The mechanisms underlying the effects of chemical admixtures on the... 

The aim of this project is designing Suitable drilling fluid applicable in deep drilling. This aim will be reached by adding a temperature-resistant polymers or nanomaterials in water-based drilling fluid, Rheological properties of drilling fluid checked. Stability of rheological properties of drilling fluids not constant in HT state. Chain of cause and effect will happen, While the temperature increases, the viscosity and yield point of the fluids decreases. cuttings transportation and removal efficiency will be decreased due to reduction in yield point and viscosity. Evaluation of The effect of these cases conclude that these effects will also impact on filtration loss. The reason is that... 

In recent years, utilizing the colloidal gas aphron (CGA) drilling fluids is getting more and more commonplace due to their little formation damage and filtration loss. This study tries to investigate the effect of presence of nanoparticles and their type (hydrophobicity) on stability and performance of water and oil based CGA drilling fluids. This is done through analyzing stability, filtration, rheology, and pore blockage tests. Water and oil based CGA drilling fluids consisted of stabilizer, surfactant, and nanoparticles are generated and through examining of the effects of polymer, surfactant, and nanoparticle concentrations, the optimum formulation is obtained. High pressure-high... 

Acidizing efficiency depends on various factors such as formation properties, reservoir and stimulation fluid types and injection scenario. Among these factors, heterogeneity of reservoir’s formation (layered reservoirs and permeability variation versus depth) strongly affect acidizing performance. Accordingly, applying a reliable technique that distribute stimulation fluid uniformly is essential. The aim of carbonate matrix acidizing is to improve fluid flow specially in low permeability zones. Stimulation fluid cannot enter into the low permeability layer due to existence of high permeability layers which are in contact with low permeability ones. So, the stimulation fluid should be... 

Numerous applications of Lab on a Chips (LOCs) in chemical/biochemical analyses as well as the emergence of advanced methods for their manufacture attracts many researchers’ attention to these micro instruments. Low sample volume consumption and their high controllability are accounted as the main advantage of LOC systems. Micromixers are among the main components of any LOC in which mixing and/or reaction among two components occur. Micromixers have many potential applications in biological and medical sciences, and so they are repeatedly charged by biofluids. Due to sensibility of biofluids, to avoid disintegration, applying electroosmotic flow instead of pressure-induced flow has priority... 

Since the early 90s, nanotechnology has contributed to several developments in a wide range of Science and industry such as medicine, Physics, Chemistry, Aerospace, electronics and Biology. In recent years, nanotechnology has also made development in the oil and gas industry. The drilling fluid is already one of the most important parts in drilling operation.The physical properties of a mud, rheological properties and minimize fluid invasion into the formation with perfect mudcake are important to assist in optimizing results. Nano-materials as one of the achievements of recent years are effective in achieving these purposes. To obtain the above properties, a variety of polymers as... 

One of the major problems in directional and extended reach wells is poor hole cleaning. Directional and horizontal drilling is more complex than vertical wells. Ineffective particles transport leads to several undesirable issues during drilling. This thesis analyzed all parameters which have directly affected directional hole cleaning. The thesis is based on an experimental set-up designed in Sharif University. In the experimental work, two types of drilling fluid, Newtonian and Non-Newtonian with numerous rheological parameters, three different flow rate, three various nozzle sizes and three individual RPMs in three distinct inclinations 30°, 60° and 90° were used to simulate. Also, to... 

For designing a unit operation, knowledge about physical properties is essential. This is attained either by direct measurement, which needs spending time and cost or, using proposed correlations. This project is subjected to theoretical analysis of viscosity as the most important rheological property of dilute suspensions of microgels, or in other words colloidal suspensions of porous spheres. They are applied in drug delivery, enhanced oil recovery, synthesis of catalyst and adsorption of heavy metal ions from aqueous systems for water purification purposes. In dilute suspensions particles are faraway from each other and there is no interaction between them therefore, it is better to... 

Drilling of low pressure layers is one of the major problems in petroleum industry, in which requires a lightweight drilling fluid for drilling of these layers. Use of lightweight Colloidal Gas Aphron (CGA) leads to loss reduction of drilling fluid, decreases formation damage and finally, well stimulation costs will be reduced. Use of nanoparticles can improve the aphron drilling fluid performance. But there is little information in the literature about the role of natural surfactant in the presence of nanoparticles on the CGA based fluid properties. Especially, micro bubbles behavior in the presence of nanoparticles in pore scale is less considered. This study consists of two parts, in the... 

This investigative study intends to identify and characterize bitumen from seven Iranian bitumen production plants according to the Superpave Performance Grading (PG) system, conventional classic tests, and chemical separation tests. The study then compares the identified performance grades with the thirteen performance-grade binders required for specific climatic zones in Iran. It is observed that the variety of available binders is not adequate to fully cover the required PGs. Blending was initially considered as a suitable and economic method for production of the missing performance grades. However due to similar rheological properties of bitumen samples, resulting in nearly identical...