Emulsifier is a kind of surfactant. Surfactants have the function of emulsification and others. The main function of surfactant is to remove stains, emulsification, solubilization, suspension aid, foaming and defoaming, sterilization, etc. There are many kinds of surfactants. According to the classification of use, there are emulsifiers, demulsifiers, antistatic agents, detergents, foam stabilizers, defoamers, dispersants, etc. These purposes can be distinguished according to the size of the HLB value. A wide range of surfactants, including emulsifiers. The HLB value of surfactant is 0-40, while that of emulsifier is about 2-15. 2-8 is water in oil emulsifier, and 9-15 is oil in water emulsifier.
Surfactants are substances containing hydrophilic and hydrophobic groups. Surfactants are substances with fixed hydrophilic and lipophilic groups, which can be arranged directionally on the surface of the solution and can significantly reduce the surface tension. Emulsifier is only a kind of surfactant, or a kind of performance, and it can also be used as penetrant.
The mechanism and application of surfactant in tertiary oil recovery.
1) Active water drive. It is the only way to inject surfactant aqueous solution into the oil layer. Its surfactant aqueous solution can reduce the dispersion of crude oil in water; B change the wettability of the formation surface; C Increase the dispersion of crude oil in water; D Change the fluidity of crude oil, reduce the maturity of crude oil and the ultimate shear stress.
2) Alkali water flooding. Alkali water flooding is a method to make naphthenic acid in crude oil react with alkali to form soap surfactant. The cost of this oil recovery method is low, but it is generally more effective to add some auxiliary surfactants.
3) Thickened water drive. Thickener can be used to improve crude oil recovery, partially hydrolyzed polyacrylamide can be used as the viscosity increaser of injected water, and sometimes fatty alcohol polyoxyethylene ether sulfate or sulfonate and surfactant can be used as the thickener.