Experimental investigation of silica nanoparticle size effect on oil recovery in carbonate reservoirs

Rock wettability is one of the main factors which plays a vital role in oil recovery. In this study, theeffect of silica nanofluid concentration and nanoparticle size on the wettability of carbonate reservoirrocks was investigated. Oil-aged thin sections were soaked in different nanofluid samples with differentconcentrations and nanoaparticle size at ۸۰°C. The effect of nanofluid on wettability alteration wasstudied by measuring the contact angle. Results showed that wettability altered from oil-wet to waterwetafter adsorption of nanofluid on the rock surface. By reducing nanoparticle size from ۱۵۴.۹ nm to۲ nm, contact angle reduces about ۳۷%. In addition, the presence of NaCl plays a positive role until aspecific concentration (۲۰۰۰۰ ppm). The optimum concentration obtained was ۰.۰۲ wt. % that changedcontact angle from ۱۴۰.۲° to ۳۵.۸۶° at ۲۰۰۰۰ ppm NaCl.

Keywords:

Nanofluid , Wettability , Silica nanoparticle , Carbonate Reservoirs