Water-based mud is known as an environmental-friendly drilling fluid system. The formulation of water-based mud is designed to have specific rheological properties under specific oil field conditions. In this study, graphene nanoplatelet and silver nanoparticle (nanosilver) were added to a water-based mud formulation in which they act as drilling mud additives. Rheological properties measurements and filtration tests were conducted for evaluating the influence of the added nanoparticles. The results showed that the graphene nanoplatelet and the nanosilver increased the plastic viscosity (PV) by up to 89.2% and 64.2%, respectively. Meanwhile, both the yield point (YP) and the fluid loss values were reduced. In addition, we believe this is the first result ever report where nanosilver is utilized for enhancing-enhanced water-based mud's performance.