Acrylic Acid-Modified Cellulose Nanocomposite: A Promising Green Solution for Shale Inhibition in Water-Based Drilling Fluids

Drilling operations in shale formations often encounter challenges due to wellbore instability caused by shale expansion. Addressing this issue is crucial to minimize non-productive time and control associated costs. In this study, we synthesized acrylic acid-functionalized cellulose diacrylate carbon nanocomposite and investigated its potential as a shale swelling inhibitor and fluid loss controller in water-based drilling fluids. To evaluate the inhibitory effects, linear swelling tests were conducted using varying concentrations (0.2, 0.5, and 1.0) wt%. Furthermore, rheology and fluid loss tests were performed to assess the performance of the drilling fluids. The experimental results demonstrated a significant reduction in linear swelling of bentonite clay with the addition of nanocomposite. The extent of reduction correlated with the concentration of nanocomposite, with reductions of 37.06%, 46.63%, and 56.8% observed at concentrations of 0.2%, 0.5%, and 1.0wt% respectively, compared to deionized water. The nanocomposite improved the rheological parameters as plastic viscosity, yield point and gel strength parameters enhanced. The carrying capacity of the drilling fluids improved with the addition of nanocomposite. Moreover, the inclusion of nanocomposite resulted in a notable decrease in fluid loss. The fluid loss of nanocomposite mixed drilling fluid was reduced by 26% compared to the base fluid. This reduction was attributed to the formation of a compact film that effectively blocked nanopores, impeding water invasion. The findings of this study highlight the strong candidacy of nanocomposite as an environmentally friendly shale inhibitor alternative for water-based drilling fluids.