CO2 foam flooding system for low-permeability and ultra-low-permeability reservoir as well as preparation method and application of CO2 foam flooding system

Abstract

The invention discloses a CO2 foam flooding system for a low-permeability and ultra-low-permeability reservoir and a preparation method and application, and belongs to the field of chemical flooding, alkylamine and methyl acrylate are added into a solvent for a Michael addition reaction, and NDFEn is obtained; dissolving NDFEn in a solvent, adding o-dichlorobenzyl, and carrying out a substitution reaction; carrying out saponification reaction on a product of the substitution reaction and a NaOH solution; adding diluted hydrochloric acid into a saponification reaction product, stirring, and washing the product after suction filtration; and recrystallizing the washed product, and drying to obtain a final product recorded as NDSPn. The prepared novel carboxylate gemini foaming agent is adopted as a main foaming agent to be compounded with an auxiliary foaming agent and a foam stabilizer, and the compound system foaming liquid has low viscosity, good CO2 foam comprehensive performance and low oil-water interfacial tension, has good injectability, also has the capability of improving the oil washing efficiency, has a remarkable effect of improving the recovery efficiency in low-permeability and ultra-low-permeability oil reservoirs, and has a good application prospect. Good application prospects are realized.

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