Abstract: A surfactant that changes the wettability of tight sandstone and its preparation method and application. By adding the aqueous phase solution into the oil phase solution, and under the action of the emulsifier, a uniformly dispersed phase is achieved. Then adding initiator, stirring and raising the temperature, reacting the reaction at the temperature to obtain a colorless and transparent liquid, i.e., high polymer. At room temperature, adding fluorocarbon surfactant and biosurfactant and stirring was continued for 4 hours to obtain a surfactant that changes the surface wettability of tight sandstone. The surfactant of the present invention can reduce the oil-water interfacial tension, transform the oil-wet surface into water-wet surface, which reduces the adhesion of oil droplets to rock surface and improves the flowability of crude oil in the original stratum, and improves the recovery of low-permeability reservoir.

Abstract: Disclosed is an additive composition that can be mixed with various types of basic oils to produce a lubricant that can meet the international standards of manual truck gearbox oils. A preferred embodiment includes various quantities of an isobutylene sulfide, zinc dialklydithiophosate and other components. Component properties of the additive composition are selected to produce a lubricant that has good thermal stability, rust-resisting and endurance qualities and that has a low cost of use and production.