Effects of low-salinity water coupled with silica nanoparticles on wettability alteration of dolomite at reservoir temperature

ABSTRACT

Wettability alteration in porous media is one of the mechanisms for enhancing oil recovery through injecting low-salinity water into carbonate reservoirs, in which active ions can remove the carboxylic oil component from the rock surface, altering the rock's wettability toward a water-wet condition. This study investigated the concomitant effects of low-salinity water and hydrophilic SiO₂ nanoparticles on oil-wet dolomite rock. Results revealed that low-salinity water coupled with hydrophilic nano-SiO₂ in oil-wet dolomite rock remarkably affected the wettability alteration of the rock, showing that the simultaneous presence of ions in water and hydrophilic nano-SiO₂ led to considerable wettability alteration compared with using just low-salinity water.

KEYWORDS:

• Double layer
• ions (SO₄^2–, Mg²⁺, Ca²⁺)
• low-salinity water
• nano-SiO₂
• wettability alteration