Evaluation of nanoparticle effect on heavy and light wellbore cement slurries

Abstract

Cementing around the casing in oil and gas wellbores provides multiple benefits such as proper zonal isolation, casing support, and prevention of fluid migration. Wellbore cement is an important part of the completion and abandonment process. However, wellbore cement has some drawbacks such as micro-annuli formation or loss of zonal isolation. Nanoparticles (NPs) have been shown to improve the characteristics of wellbore drilling fluids but have not been used extensively in cement. The objective of this paper is to show the effect of NPs’ concentration on wellbore cement characteristics such as thickening time, viscosity, and fluid loss properties. Nanoparticle barite and magnetite were added to heavy cement and bentonite was added to light cement in intervals of 1, 3, and 5 % by weight of cement to test the resulting cement characteristics. The results showed that the thickening time increased for all concentrations of nanoparticles, except for the 5 % magnetite. The resulting yield stress of both cement mixtures increased for all concentrations of nanoparticles. The viscosity for all concentrations of nanoparticles in the heavy cement was greater than the control case, while no change in viscosity was seen with the light cement. Fluid loss generally decreased by increasing nanoparticle concentrations for both heavy and light cement. The results of this work in combination with results from the literature show that the addition of barite, magnetite, or bentonite nanoparticles can enhance wellbore cement without diminishing the pumpability and curing time.

Keywords

• Wellbore cement
• Nanoparticles
• Thickening time
• Rheology
• Fluid loss
• Wellbore integrity