Drilling fluid lubricant and preparation method and use thereof

A preparation method of a drilling fluid lubricant, characterized by comprising the following steps:

• 1) mixing styrene and water, then adding a nano-inorganic intermediate, a crosslinking agent and an emulsifier and stirring to obtain a first mixture;
• wherein a mass ratio of the styrene to the water is 1:(4.5-6.5);
• a mass ratio of the styrene, the nano-inorganic intermediate, the crosslinking agent and the emulsifier is 1:(0.01-0.1):(0.04-0.06):(0.018-0.032);
• 2) under an inert atmosphere, stirring the first mixture to obtain an intermediate emulsion;
• then heating the intermediate emulsion to 70-85° C., then adding an initiator, keeping temperature and stirring for 7-10 hours to obtain an emulsion of polystyrene nanocomposite with a particle size of 40-90 nm;
• a mass ratio of the styrene to the initiator is 1:(0.002-0.008);
• the emulsion of polystyrene nanocomposite being sequentially subjected to a granulating treatment to obtain polystyrene nanocomposite particles;
• 3) mixing industrial base oil, polystyrene nanocomposite particles and industrial oleic acid, and stirring evenly at room temperature to obtain the drilling fluid lubricant;
• wherein a mass ratio of the industrial base oil, the polystyrene nanocomposite particles and the industrial oleic acid is 1:(0.005-0.025):(0.04-0.09).