Preparation and application of an environmentally friendly compound lubricant based biological oil for drilling fluids

As the basic raw material of bio-oil based eco-friendly lubricant, a special selected by-product vegetable acidified oil (AO) was modified by vulcanization, esterification, or vulcanization followed by esterification. The optimized vulcanization process conditions are 1% sulfur powder catalyzed, temperature 130 ℃, reaction time 2 h, while the optimized esterification process requires 20% glycerol and 1% H2SO4 catalysis, reaction temperature 220 ℃, reaction time 3 h. We compounded modified AO, diluent, pour point depressant and emulsifier into an advanced drilling lubricant F-1. F-1 has excellent performances in bentonite drilling fluids, the extreme pressure lubrication coefficient reduction rate (Δf) in fresh water mud is 86.84%, and 85.76% in 4% NaCl salt water mud. After aging at 150 ℃ for 16 h, its Δf is improved compared with room temperature. Adding F-1 to the basic bentonite mud system, the filtration loss of drilling fluids decreased from 10 mL to 6.5 mL, the apparent viscosity and plastic viscosity experienced little change before and after aging. The new bio-oil compound lubricant has an excellent temperature resistance, a high salt contamination resistance and cost-effective. Vulcanization and esterification processes help to improve the lubricity and reduce foaming rates.