Abstract
Drilling fluid technology is one of the most targeted and developed technologies worldwide due to the increasing demand for deeper drilling and more complicated wells. Several studies have shown numerous improvements in the mud characteristics when using nanoparticles (NPs) as additives. This study aims at examining the influence of using aluminium oxide (Al2O3) and copper oxide (CuO) NPs on the characteristics of KCl-polymer mud, which is mainly used while drilling shaly formations. Two sizes of Al2O3-NPs (15 and 40 nm) in addition to CuO-NPs (40 nm) were investigated at different concentrations (0.1, 0.3, 0.5, 0.7, and 1.0 wt.%) using a standard viscometer and API filter press. Zeta potential (zeta-potential), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) were used to elaborate the effect of NPs on the properties of NPs-based KCl-polymer mud. The results showed higher potential of Al2O3-NPs and CuO-NPs to enhance the mud properties when used at small concentrations of 0.3-0.5 wt.%. Furthermore, NPs were found to play a key role in building efficient filter cakes with time during filtration (up to 90 min). Moreover, smoother surface morphologies and less porous structures of filter cakes were observed when using NPs with some agglomeration of CuO-NPs due to higher density. The Herschel-Bulkley model was found to provide a better fitting of the rheological data of NPs-based KCl-polymer mud than the Bingham plastic model. This approach would be able to virtually overcome any shale issue encountered by proactively plugging nanopores while inhibiting the water absorption in shale formations.