Caracterização de sistemas microemulsionados para aplicação na recuperação avançada de petróleo

Abstract

The reservoirs, after exhaustion of its natural energy, retain large quantities of hydrocarbons. On average, the recovery factor after primary and secondary oil recovery operations is between 30 and 50% and this can be attributed primarily to the high viscosity of the oil, the geology of the formation and high interfacial tension between the fluids reservoir. Therefore, it is necessary to apply the so-called enhanced recovery methods in order to increase the oil displacement. Colloidal systems have been studied as alternatives in the search to increase ease of displacement of the oil. The surfactants based systems are intended to reduce the surface tension between the reservoir rock and the oil, while the polymer acts giving load to the injected fluid to improving the mobility of the trapped oil in the rock. There is also the use of microemulsion systems, since they are thermodynamically stable and have the ability to reduce interfacial tensions, acting directly on the residual oil. From this context, this work aims to study the characterization of microemulsion systems (M systems) and microemulsion with polymers (P systems), in order to compare these systems and study, especially, the interfacial interaction phenomena and charge simultaneously using the droplet size techniques, surface tension, contact angle and rheology for help to elucidate the phenomena involved. The selected microemulsion systems were obtained by choosing points from a pseudoternário diagram using distilled water (FA), heptane (FO), secondary butanol (C) and Ultranex 120 (T) in a ratio T / C = 1.A microemulsion region is rich in aqueous phase, which facilitates the solubility of the polymer (polyacrylic acid). Six formulations were selected in the diagram. The formulations had oil phase of 5% w/w, while the percentages of C/T and FA were varied in a range of 35% to 60%. Six other systems have been created with the addition of the 0.2% w/w polymer. Finally, the M1 e P1 systems were selected as they showed the best properties for future applications in advanced recovery testes, since they provide a lower cost with reagents and, even so, achieved satisfactory results.