Summary of traditional drilling fluid lubricants.

Traditional lubricants	Shortcomings
Inert solid particles	Not degradable and prone to damage to the formations
Crude oil, diesel	Deterioration of performance of water-based drilling fluid, environmental pollution, and high disposal cost of drilling fluid after mixing with the oil
Zinc dialkyl dithiophosphate (ZDDP)	The decomposition of ZDDP produces toxic compounds containing S/P, causing environmental pollution
Mineral oil-based lubricant	Aromatics contain fluorescence, which affects logging work