Abstract:Nanoparticle flooding and low-salinity waterflooding are widely studied by researchers as new and popular enhanced recovery technologies. To further investigate the synergistic effect of ZrO2 nanoparticles and low-salinity water, the low-salinity water is now obtained by diluting the formation water of the Taha oil field by 110 times to obtain 5% additional recovery and is used as the optimal low-salinity water. In order to improve the dispersion of ZrO2 nanoparticles in low-salinity water, a modified ZrO2 nanoparticles by the coupling agent 3-aminopropyltrimethoxysilane was prepared. Infrared spectroscopy, transmission electron microscopy and thermogravimetric analyzer were used to analyze and characterize the particles. Dispersion stability, interfacial properties and oil displacement effect of nanofluids combined with FW-110 times low- salinity water and modified ZrO2 nanoparticles were evaluated. The dispersibility of the modified nanofluid was improved from 22.9 to 7.6; the interfacial tension was further reduced by 2 mN/m; the wettability of the rock surface was further shifted to water-wetness; the work of adhesion was further reduced by 8 J/cm2; and the increase in temperature had a positive effect on the reduction of the interfacial tension, contact angle, and work of adhesion. The optimum concentration of particles was 0.02 wt% at 0.005 wt%~0.05 wt%, when the highest indoor recovery rate was achieved, with a value-added recovery rate of 12.6%, which provided a theoretical basis with obvious advantages and broad prospects for popularization and application.