Investigation on the stability of mixed AlOOH/SiO2 aqueous dispersions and their application to stabilize Pickering emulsions in the presence of TX-100 and enhance oil recovery

Abstract

Both negatively charged SiO2 nanoparticle and positively charged AlOOH nanoparticle have been widely used in various fields, including enhanced oil recovery (EOR). In this study, the mixed binary AlOOH/SiO2 nanoparticle (MBN) systems are constructed and firstly employed in EOR. The measurements of zeta potential and Z-average diameter indicate that the stable MBN aqueous dispersion could be obtained by controlling AlOOH/SiO2 mass ratios, which is quantificationally confirmed via the e-DLVO theory. Then the ternary TX-100-AlOOH-SiO2 (TX-A-S) system exhibits the great ability to stabilize the emulsion at the much low nanoparticle concentration (0.15 wt% in total). The emulsion stability is further evaluated in the harsh conditions (high shear, temperature and electrolyte concentration). Moreover, core flooding and microscopic visualization experiments reflect the TX-A-S stabilized emulsion can dramatically enhance tertiary oil recovery (~23% of initial oil in place), which should be attributed to the high improvement of both displacement and sweep efficiency.