Sharif Digital Repository

In this study, the influence of multi wall carbon nanotube on the thermal properties and microstructure of open cell flexible polyurethane (PU) foam was investigated. To do this untreated CNT (named here n-CNT) along with three different highly functionalized CNTs having carboxyl, hydroxyl and amide functional groups, abbreviated here by CNT-COOH, CNT-OH and CNT-NH-COR, respectively, were employed. A series of PU foam with and without CNTs (both treated and untreated ones) were prepared by cast molding. Prior molding, the CNTs (0.1 wt% loading) were first dispersed into the polyol (Mw = 3000 g/mol and OH No. 56) and then the mixture was subsequently added to the isocynate (TDI). The SEM... 

When oil spill take place, it should be removed rapidly. For control of oil pollution, polymeric foams that absorb oil highly, can be used. These foams are polyurethane and polypropylene that float on water and absorb several times their own weight of crude oil. When a thin layer of crude oil remained on water, it couldn’t be separated by chemical and physical methods. In this cases biological methods will be best and suitable. Therefore absorption and biodegradation of oil spill are executed by immobilization of suitable microorganism on polyurethane foam. But current polyurethane foams aren’t biodegradable so this incompetence should be solved. Polyurethane foams compose of two basic... 

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... 

NiTi Memory alloys have a great range of applications. Porous metallic biomaterials (e.g., stainless steel, chromium- cobalt, titanium and nickel–titanium (NiTi)) represent superior alternatives to traditional non-porous metallic implants for two main reasons. First, open porosity can enhance bone ingrowth and thus improve fixation at the interface between bone and implant. Second, porosity decreases the mismatch in stiffness between bone and implant, thus reducing stress-shielding effects which shorten the lifetime of the implant through bone resorption and loosening. NiTi foams may thus find multi-functional applications such as bone implants, impedance-matching connectors between... 

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... 

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... 

One of the most common methods for enhancing oil recovery is gas injection. Because of greenhouse effect and environmental problems, carbon dioxide can be used as injected gas. Low viscosity and high relative permeability of gas make the gas injection as an ineffective EOR method. Foam injection is a good replacement because its mobility is much higher than gas. Usually surfactants are used as foam generator agent but the generated foam is not so stable. Using nanoparticles can improve foam stability for a longer time. In this research study fly ash particles is used as a new stabilizer agent to improve carbon dioxide foam stability. This particles are made of silica, aluminum, iron …... 

Underbalanced drilling is a type of drilling operation in which the pressure of the drilling fluid is less than the pressure of the formation. This pressure difference has created advantages for this method. Less formation damage, reduction of pipe stuck, increasing rate of penetration and production during drilling are the advantages of this method compared to traditional methods. To reduce the pressure of the drilling fluid, very low density fluids should be used. One way to reduce density is to mix a compressible fluid such as gas into water. Due to the difference in density and surface tensile strength of water and gas, these two phases do not combine, so a stable combination of these... 

Auxetic materials have a negative Poisson ratio (NPR), which is their most distinguishable characteristic as compared to regular materials. Test specimens were made of conventional polyurethane (PU) foams according to ASTM ; then, with a thermo-mechanical process, the foam was converted to auxetic PU foam. The reproducibility of specimens' fabrication was checked with CoV= for the final foam thickness. With regard to the fact that changing loading conditions can vary Poisson's ratio, in this study, the variations occurred in Poisson's ratio due to changing loading conditions are investigated. The applied strain and strain rate were altered in experiments and statistical analysis was... 

The primary purpose of acidizing operations in the oil and gas industry is to enhance hydrocarbon production. Acidizing has been a common and conventional method for years, especially when production engineers face issues like declining reservoir pressure leading to reduced production rates. Initially, the treatment solution is referred to as matrix acidizing. In acidizing operations, different additives are combined with the acid to control its behavior in the reservoir. These additives may include iron control agents, corrosion inhibitors, friction reducers, and more. Incompatibility among these additives, the acid, and reservoir fluids can lead to severe damage to the reservoir....