Impact of Nanoparticles on Clay Sedimentation in Liquids

Abstract

Clay sedimentation in colloids is a natural phenomenon that can be accelerated or retarded with additives. This is important in drilling operations where clay suspension in drilling muds is desired for effective functionality. Current studies have indicated that nanoparticles can improve rheological properties of drilling fluids but not much is known about their impact on clay sedimentation. Hence, this work investigates the effect of eight kinds of nanoparticles on clay sedimentation in the absence and presence of crude oil. A small fraction of these nanoparticles were dispersed in distilled water, brine of 30g/l salinity, ethanol and diesel containing clays, and the volume of settled particles under gravity were plotted against time. Linear graphs and parabolic shaped graphs within the short periods of observation indicate slow and accelerated sedimentations respectively.  Results show that aluminum oxide and zinc oxide nanoparticles speed up clay sedimentation while nanoparticles of magnesium, zirconium, nickel, iron, tin and silicon oxides retard clay sedimentation rate in liquids, rendering these six kinds of nanoparticles potential clay stabilizers. In the absence of nanoparticles it was observed that clay sedimentation in water is slower than in ethanol and diesel and the presence of crude oil further slows down sedimentation. But in the presence of nanoparticles, the effect of crude oil on clay sedimentation is inconclusive, necessitating further studies.