Desenvolvimento de nanofluido baseado no efeito combinado de nanopartículas de sílica e água de baixa salinidade para recuperação avançada de petróleo

Abstract

Recent studies have indicated that nanofluids that combine silica nanoparticles and low salinity water have a promising character as Enhanced Oil Recovery agents for application in sandstones. In view of that, the aim of this work is to investigate the effects that low-salinity silica nanofluids induce on fluid/fluid and rock/fluid interactions in order to generate contributions to the understanding of the oil recovery mechanisms of this potential injection fluid. Therefore, experimental analyzes were carried out with nanofluids containing silica nanoparticles at concentrations between 0.01 and 0.2 wt% dispersed both in deionized water and in a low salinity water containing a Total Dissolved Solids of 1343.4 mg/L. The results showed that the dynamic viscosity of the nanofluids exceeds that of deionized water by, at most, only about 4.23%. The zeta potential of silica nanoparticles was significantly decreased when they were dispersed in the low salinity water. On the other hand, the size of the silica nanoparticles in the nanofluids did not increase over 200 nm and was not consistently affected by factors such as nanoparticle concentration, dispersing fluid or time elapsed after sonication of the nanofluids. The interfacial tension between crude oil and deionized water was not substantially changed when the aqueous phase was replaced by the nanofluids. The contact angle analyzes showed that the introduction of silica nanoparticles at a certain optimum concentration (about 0.05 wt%) in the low salinity water strengthens the wettability alteration of sandstone surfaces aged with crude oil towards more water-wet conditions.