Comparative analysis of the effect of single-walled and multi-walled carbon nanotube additives on the properties of hydrocarbon-based drilling fluids

Abstract

The article presents the results of a comprehensive comparative analysis of the effect of single-walled and multi-walled carbon nanotubes on the main performance characteristics of mineral oil-based drilling emulsions. Such a systematic comparative study of hydrocarbon-based solutions has been performed for the first time. Weight concentration of single-walled nanotubes varied from 0.01 % to 0.1 %, and of multi-walled ones, from 0.1 % to 0.5 %. The formulation and preparation technique of stable drilling emulsions with single-walled and multi-walled nanotube additives were practiced. The effect of nanotube additives on rheology, filtration, and antifriction properties, as well as colloidal stability, and clay inhibition kinetics of hydrocarbon-based drilling fluids has been studied. As a result of the study, it has been successfully demonstrated that adding even very small amount of carbon nanotubes allows significantly controlling the main performance characteristics of drilling fluids. Thus, adding just 0.025 wt% of single-walled nanotubes increases effective viscosity of the drilling fluid by about 45 %, the yield stress – by 1.7 times, colloidal stability – by 36 %, reducing at the same time filtration loss by 55 %, and friction factor – by 20 %. At the same time, it has been shown that using single-walled nanotubes is several times more efficient compared to adding multi-walled nanotubes, and hundreds of times more efficient compared to using spherical metal oxide nanoparticles.