الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Since the amount of oil remaining after the extraction of conventional methods of accounting for nearly 67 % of the total oil reserves, research has gone to a number of ways to increase revenues, including thermal recovery of petroleum, gas injection, microbial injection, and chemical injection. In this study, hydrophilic polymeric nanocomposites were evaluated in enhancing oil recovery (EOR) as a new emerging class of materials in this field. The prepared nanocomposites have high molecular weight and high thermal stability. Moreover, they have the ability to increase wetting of rocks as a result of retention of nanometer composoite by porous medium and decreasing contact angle and interfacial tension of oil-water system. In this regard we prepared two types of magnetite nanoparticles, a hydrophilic type including bare magnetite (G) and citric acid coated magnetite (CG) and a hydrophobic type comprising oleic acid coated magnetite (OG). The chemical composition of these types was proven using FTIR and X-ray diffraction. Poly (sodium methacrylate) (PNaMA) nanocomposites based on these magnetite nanoparticles besides organophilic clay were prepared via microemulsion polymerization technique. Morphology of the prepared nanoparticles and the corresponding nanocomposites were evaluated using transmission electron microscope (TEM). Encapsulation of magnetite nanoparticles was elucidated by magnetic properties of nanocomposites. Their evaluation as EOR candidates were performed through evaluating their thermal stability, viscosity, surface tension, contact angle and interfacial tension. The results showed that the prepared nanocomposites have higher thermal stability than crosslinked PNaMA itself and those based on G nanoparticles give best results. Thermal stability is generally enhanced by increasing crosslinker concentration. All nanocomposites show thixotropic behavior thus have the ability to improve water oil mobility ratio. In addition, they have the ability to decrease surface tension of brine water, enhance wettability as shown by contact angle measuremants, decrease interfacial tension between oil and brine water.