Abstract: In order to meet needs of exploratory well, development well and environmental protection, an inert filtration reducer DJ-3 which is low fluorescent or non-fluorescence and low poisonous or non-poisonous was successfully developed by using straight chain saturation alkane based on the equilibrium principle of dispersion and collection. The efficiency of DJ-3 in fresh
water, positive electricity colloid and high density salt water mud was synthetically evaluated and compared to sulfonated asphalt. Results show that DJ-3 has many good properties such as filtration reducing, lubrication, anti-collapsing, covering and plugging, temperature resistance (>150℃), salt-resistance (7%NaCl+7%KCOOH) and so on. DJ-3 has good compatibi
ity with AP-P1 and KCOOH, and also has good filtration reducing and rheological property in high temperature(150℃)and high density(2.0 g/cm3) mud system. It is a good filtration reducer in positive electricity colloid mud. It is a non-fluorescence and low poisonous or non-poisonous additive. Its whole
efficacy is better than sulfonated asphalt such as HL-Ⅱ, SAS.So DJ-3 is a good succedaneum of sulfonated asphalt.

Key words: low fluorescence or non-fluorescence, poison, inert, filtration reducing additive, covering and plugging, lubrication