500 g of drilling fluid lubricant and drilling fluid were shear mixed and then hot rolled for 16 hrs 120 f table 2 shows that the addition of zddp to the lubricant resulted in a reduction in the cof of the lubricant a sample of potassium silicate based drilling fluid was obtained from a well site in western canada the drilling fluid contained 6 5 potassium silicate by volume and remainder being water polymers and drill solids estadril was blended 19 1 with zddp on a wt wt basis lubricant was added to the drilling fluid on a 2 wt wt basis table 3 shows that a 0 5 loading of zddp enhanced lubricant had a similar cof as a 2 loading of lubricant zddp does not have to be pre mixed into a base lubricant prior to adding to the drilling fluid a comparison was made between zddp that was blended into a lubricant vs zddp and lubricant added separately into a drilling fluid blended lubricants have a ratio 9 parts lubricant to 1 part zddp lubricants were tested in a potassium silicate based drilling fluid containing 8 potassium silicate by volume and a sodium silicate based drilling fluid containing 8 sodium silicate glycol based drilling fluids represent a class of water based drilling fluids that provide shale inhibition a glycol based drilling fluid was formulated with 8 v v polyethylene glycol peg 300 polymers water and simulated drill solids lubricity testing was done on zddp by itself as well as lubricant blended with zddp 9 1 table 5 shows a reduction in the cof when zddp is added to the lubricant amine based drilling.