Anionic-nonionic amphoteric surfactant for oil displacement, and preparation method thereof

Abstract

The invention relates to an anionic-nonionic amphoteric surfactant for oil displacement, wherein the surfactant is the phloroglucinol disulfonate of alkylphenol polyoxyethylene ether and lignin alcohol ether, the chemical general formula is represented by a formula 1 defined in the specification, R1 is C9-C16 branched chain or linear chain alkyl, x and y are the addition numbers of ethoxy groups,x is 8-20, y is 6-10, Lignin is lignin in English and represents the structure of lignin, and Y is an alkali metal. According to the present invention, with the anionic-nonionic amphoteric surfactant,the tension at the water-oil interface can be reduced, the molecular hydration ability of the surfactant can be improved through different nonionic hydrophilic groups, and the interaction between theion head group and the metal cation in the solution can be weakened.

Description

technical field [0001] The invention relates to the field of oil displacement additives for oil fields, in particular to an anionic nonionic amphoteric surfactant for oil displacement and a preparation method thereof. Background technique [0002] With the prolongation of development time, some large domestic oilfields, such as Daqing Oilfield and Shengli Oilfield, have comprehensive water cut close to or 90%. Due to the large original geological reserves of these oilfields, the total recovery rate is still less than 50% when water flooding reaches 100% water cut. Therefore, in order to maximize the recoverable reserves of the oilfield and maintain a relatively high oil recovery rate, some tertiary oil recovery technologies that reduce the interfacial tension between oil and water by injecting surfactants, improve oil displacement efficiency, and finally achieve a substantial increase in oil recovery, Technologies such as alkali-surfactant-polymer ASP flooding and foam comp...

AI Technical Summary

Problems solved by technology

Due to the large original geological reserves of these oilfields, the total recovery rate is still less than 50% when water flooding reaches 100% water cut

[0005] Conventional lignosulfonate produced from lignin is a commonly used surfactant in China, but its surface activity is poor, and it is mainly used as a dispersant for liquid-solid dispersion systems. Usually, the surface tension of its aqueous solution is about 50mN / m. Moreover, the critical micelle concentration is very high, and the modified lignosulfonate, after introducing lipophilic components in its structure, has high water solubility, but it cannot form ultra-low interfacial tension with crude oil when used alone, so it cannot be used directly oil drive

Images