The currently available liquid lubricants used in drilling fluids are generally troubled by the inferior anti-high temperature, complex preparation, high foaming ratio, and fluorescence grade, which suppress the effective extension of the drilled hole and lower the drilling efficiency. This paper, with liquid paraffin as the oil phase, mixed Span 80 and Tween 80 as primary surfactants, the normal butanol as the secondary surfactant, and the Gemini quaternary ammonium compound-based surfactant GTN as the emulsion electrical regulator, developed a microemulsion lubricant, referred to as NE. The basic characteristics of such lubricant were analyzed using the Zetasizer Nano ZS90, and its lubrication performance, thermal stability, foaming ratio, fluorescence grade, and compatibility with drilling fluids were evaluated through laboratory experiments. Results showed that the nanodroplets formed in the diluted microemulsion lubricant NE were positively charged, with an average diameter of 187–258 nm. With 2% of NE, the coefficient of friction of the bentonite drilling fluid dropped by 83.8%, and the mud cake adhesion factor by 74.2%. The lubricant was featured by excellent thermal stability and was active in conditions with temperature as high as 160 °C. Moreover, with a low foaming ratio and weak fluorescence, the lubricant was well compatible with various drilling fluids, and met the field application requirement of drilling fluids.
- Drilling fluids