We aimed to improve the rheological properties of water based drilling muds (WBDM) by graphene, graphene oxide (GO), and graphene oxide functionalized with gold nanoparticles (AuNPs/GO) at 0.0005-0.01 (% w/v) ratios. For this purpose, AuNPs, graphene, GO, and AuNPs/GO were first synthesized, and then characterized by scanning electron microscopy, tunneling electron microscopy, energy-dispersive X-ray analysis, reflection absorption infrared spectroscopy, and X-ray photoelectron spectroscopy. Synthesized and characterized nanomaterials were added to WBDM at a rate of 0.0005% to 0.01% (w/v), and finally, rheological and filtration loss analyzes of water based drilling muds containing nanomaterials were carried out according to American Petroleum Institute Standards. By using nanomaterials to improve the properties of water based drilling mud, plastic viscosity, apparent viscosity, yield point, and gel strength (10 s and 10 min), increased by 67%, 44%, 44%, 67% and 50%, respectively, and at the same time, the filtration loss value decreased by 14%.