EFFECT OF NANOPARTICLES ON CLAY STABILITY IN WATER: IMPLICATION FOR WATER BASED DRILLING MUD

Abstract

Clay stability in water is essential in chemical and manufacturing processes. In water based drilling fluids, montmorillonite dispersed in water is commonly used to maintain fluid density that counter-balances pressure effects from formation layers. However, due to gravity, clay particles settlement at the bottom of holes is inevitable especially if operations in holes are suspended for technical reasons such as during fishing operations and dislodging of stuck pipes. This necessitates the introduction of additives that can enhance dispersion of clay particles in water columns. It has been reported that some nanoparticles can enhance clay stability in water; hence the primary objective in this work is to identify nanoparticles that have potentials to enhance clay stability and nanoparticles that promote clay instability in distilled water and brine of 30 g/l. In the experimental work, clays and different kinds of nanoparticles were dispersed in columns of water and the volumes of settled particles were plotted against time. Experimental results show that nanoparticles of silicon, zirconium, iron, tin, nickel and magnesium oxides all have the capacity to improve clay stability in water, while the presence of Al2O3 and ZnO nanoparticles promote clays instability in water. It is therefore recommended that further research on desirable drilling fluid properties be conducted with nanoparticle oxides that promote clay stability in water to investigate their suitability as additives in water based drilling muds.