Summary of the effect of nanoparticles on the rheology of drilling fluids.

Lubricant	Rheological properties/compatibility
Nano-SiO2/TiO2 (ref. 61–64)	The influence of nano-SiO2/TiO2 on the rheological properties of drilling fluid depends largely on its concentration and temperature
Metal borate57	Not mentioned
PQCB65	Higher PV, YP, and gel can be obtained after adding PQCB to the drilling fluid. The addition of PQCB to the weighted drilling fluid helps to increase the low shear rate viscosity and enhance the rock-carrying ability of the drilling fluid
Polystyrene/organic montmorillonite nanocomposites (PS/OMMT)66	PS/OMMT can keep the rheological properties of drilling fluid stable in the temperature range of 200 °C
JS-LUB68	JS-LUB had no obvious effect on the density and rheological properties of the drilling fluid