Abstract
The instability of wellbores in shale formations poses a significant challenge in the drilling industry. Water and ions move through shale via different complex mechanisms, leading to wellbore instability. This study explores the effectiveness of specific materials, including synthetic nanoparticles, in enhancing shale stability by sealing pores and reducing osmotic pressure infiltration. In this study, seven categories of bentonite mud ranging from 2% to 8%, as well as four combined categories of bentonite and nanoparticles, were prepared and examined. Additionally, the rheological properties of the fluid, the elastic phase, and the viscous phase as a function of frequency were measured for both groups, and the corresponding graphs were plotted. Both fluids followed the Herschel-Bulkley model, and the viscosity of the drilling fluid was plotted against frequency and shear rate. The experiments demonstrated that integrating nanoparticles into drilling fluids significantly improves wellbore stability by reducing the thickness of mud cakes and the filtrate volume. These nanoparticles effectively seal the shale pores, minimizing osmotic pressure infiltration, as evidenced by SEM images showing suitable adhesion to bentonite shale particles. This adhesion can be attributed to the role of substituent groups on the nanoparticles. SA nanoparticles improved the stability of shale formations. It can significantly reduce shale swelling by forming a barrier on the shale surface, which prevents water absorption. Adding it to drilling fluids enhances their rheological properties, making them more stable and effective at carrying cuttings to the surface. SA Nanoparticles can improve shale formations' performance and stability.
