چكيده به لاتين
Abstract:
Todays, due to the limited amount of light oil reservoirs, production of heavy oil reservoirs is more considered. Of course, production of these energy sources is not simply like production of conventional crude oil reserves and aren't easily recoverable using current technologies. Heterogeneities in reservoir structure, high viscous oil and undesirable mobility ratio and finaly high interfacial tensions between oil and water, are the essential challenges in EOR projects of these reserves. Viscosity difference of injected water and oil in waterflooding processes causes fingering of injected fluid and bypassing much oil in the reservoir. On the other hand, high interfacial tension makes more residual oil in reservoir after waterflooding operation. To recover the bypassed oil, a low-concentration polymer solution that viscosifies water is injected to improve the reservoir sweep efficiency. Various polymers for this purpose are synthesized that the most popular of them is polyacrylamide (PAM). By replacing some of the functional groups of this polymer with other monomers, e.g. sodium salt of acrylic acid and 2-acrylamido-2-methylpropane sulfonic acid (AMPS), effect of high salinity/hardness and temperature seems to be reduced specially for the samples with higher percentage of AMPS comonomer.On the other hand, using the influence of nanoparticles on the interfacial tension of oil and injected fluid, the sweep efficiency is increased. The first part of the experimental work in this study is synthesis and characterization of sulfonated acrylamide copolymers and preparation of copolymer solutions containing nanoparticles. After examining the influence of the ratio of AMPS comonomer and acrylamide (AM) and weight percent of nanoparticle (SiO2) on the viscosity of the polymer solution, the effect of AMPS comonomer on the flowing behavior of polyacrylamide and dispersion of nanoparticle into the solution and its effect on the structure of the polymer chain investigated. In the second part, microscopic and macroscopic view of the injection process of copolymer solutions containing silica nanoparticles in porous media is investigated with regard to the heterogeneity and geometric properties of the layers using glass micromodel. The results show that the presence of AMPS comonomers instead of carboxylic groups on the acrylamide main chain causes the increase in solution viscosity and more resistance to salinity and temperature. On the other hand, the decrease in the ratio of AM/AMPS monomers in polymerization process has a desires effect to achieve an optimal point after that the results are unfavorable. Injection tests showed that the dispertion of silica nanoparticles within the polymer solutions, in addition to increase the solution viscosity and reduction of mobility ratio, has influence on the interfacial tention and enhancement of the sweep efficiency.
Keywords: Enhanced Oil Recovery, Sulfonated Polyacrylamide, Silica Nanoparticle, Viscosity, Glass Micromodel.
