Effect of Nitric Acid on the Low Fluorescing Performance of Drilling Fluid Lubricant Based Animal and Vegetable Oils

Table 1

Fluorescence characteristics of lubricant before and after elimination of fluorescence.

Lubricant	The maximum fluorescence intensity 𝐹max	Corresponding EX (nm)	Corresponding EM (nm)
E167	7.725	258	332.0
Ordinary lubricant	115.2	300	385.6

The fluorescence grades of E167 are 2-3.