Challenges for extending the application of nanoparticles in high salinity reservoirs

Nanoparticles, through many researches, has proven its capability to be an enhance oil recovery agent. In this study, we aim to investigate the performance of natural Zeolite in nanoscale on the recovery of crude oil compared to the normal water flooding method. The natural Zeolite nanoparticles are dispersed in seawater, however nanoparticles stability in saline water have been reported to be a big challenge. So, in order to investigate the performance of these natural Zeolite nanoparticles on oil recovery, we should first stabilize them in seawater. Natural Zeolite nanoparticles of different concentrations (i.e. 0.02, 0.03, 0.05 wt%) were dispersed in seawater, where stability tests showed nanoparticles precipitations in less than an hour. This problem, of nanoparticles precipitation in seawater, was investigated by studying the performance of the Zeolite nanoparticles in each electrolyte that exits in seawater. The study results showed good stability of the Zeolite nanoparticles in NaCl solution that has a concentration of 0.14 wt%, however Zeolite nanoparticles will destabilize at higher concentrations of NaCl. Divalent salts that exist in seawater (i.e. MgCl2 and CaCl2) were also tested. The Zeolite nanoparticles were found to be destabilized even at very low concentrations of these salts. Therefore, surfactants should be added to seawater to help stabilizing the Zeolite nanoparticles. Many surfactants were screened, but Polyvinylpyrrolidone (PVP) was shown to be the best to stabilize Zeolite nanoparticles in seawater. Experiments were then carried out using Zeolite nanoparticles plus (PVP) all dispersed in seawater. The effect of this dispersant on interfacial tension (IFT) was investigated where results revealed decrease in IFT values. The dispersant was shown also to change the wettability to more water wet condition which was due to the Zeolite nanoparticles, as a dispersant of only seawater and (PVP) was tested and found to not alter the wettability.