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

Both negatively charged SiO 2 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/SiO 2 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/SiO 2 mass ratios, which is quantificationally confirmed via the e-DLVO theory. Then the ternary TX-100-AlOOH-SiO 2 (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.