A preparation method of hybrid fluorine-containing surfactant for oil displacement in ultra-low permeability reservoirs

Abstract

The invention discloses a preparation method of a hybrid fluorine-containing surfactant for oil displacement in an ultra low permeability oil reservoir. The method is characterized by comprising the steps: each component is weighed in parts by weight, 20 to 200 parts of solvents and 1.0 to 12 parts of catalysts are added in a three-neck reaction flask equipped with a reflux condenser, a solution containing 20 to 300 parts of solvents and 20 parts of 2-perfluoroalkyl ethanol is added dropwise in an ice bath, the reaction is stirred for 4 hours, then the temperature is raised to 45 to 95 DEG C,a solution containing 10 to 200 parts of solvents and 1.5 to 18 parts of haloalkyl sodium salt is added, and the reaction is continued for 24 to 60 hours. The reaction product is distilled off under reduced pressure to remove solvents to obtain a crude product, silica gel column chromatography separation is conducted to obtain the hybrid fluorine-containing surfactant in a yield of 65 to 90%. Thehybrid fluorine-containing surfactant has good surface and interface activity, can significantly increase a non-wetting property of a water phase on a rock surface, significantly reduces the capillarypressure of the ultra-low permeability reservoir, reduces the bound water of the rock surface, and can also enable crude oil to be easily displaced from the rock surface.

Description

[0001] 1. Technical field [0002] The invention relates to a preparation method of a hybrid fluorine-containing surfactant for oil displacement in ultra-low permeability reservoirs. The fluorine-containing surfactant can be used as an oil displacement agent in tertiary oil recovery technology, and belongs to organic chemistry, surface and interface field of chemistry and enhanced oil recovery. [0003] 2. Background technology [0004] my country's ultra-low permeability reservoirs are rich in geological reserves of petroleum. For ultra-low permeability reservoirs in China, the reservoirs basically have no natural production capacity, and can only be put into production after reservoir fracturing. Water injection development has always been the main method. The pressure is high, and the Jiamin effect is obvious. After the oil well is operated, water lock is easy to occur, and the production declines rapidly. Therefore, the recovery rate is low, and the development effect and ...

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Problems solved by technology

[0007] The purpose of the present invention is to provide a fluoroactive agent that can significantly improve the surface of the rock, aiming at the poor ability to reduce the interfacial tension of oil and water, poor salt resistance, and few varieties, which can be used in ultra-low permeability reservoirs. It has excellent water phase non-wetability, and has low surface and interfacial tension at the same time. It can be used for the preparation of low-molecular hybrid fluorine-containing surfactants for oil displacement in ultra-low permeability reservoirs. It is characterized by 2-perfluoro Alkyl alcohol C n f 2n+1 CH 2 CH 2 OH, at least one of the integer n=4~18 is a synthetic raw material, and at least one of the halogenated alkyl sodium salts is another synthetic raw material, and the halogenated alkyl sodium salt includes chloroalkyl sodium Cl(CH 2 ) m COONa, integer m=2~5, sodium bromoalkylate Br(CH 2 ) m COONa, integer m=2~5, sodium iodoalkylate I(CH 2 ) m COONa, integer m=2~5, sodium chloroalkylsulfonate Cl(CH 2 ) m SO 3 Na, integer m=2~5, sodium bromoalkylsulfonate Br(CH 2 ) m SO 3 Na, integer m=2~5, sodium iodoalkylsulfonate I(CH 2 ) m SO 3 Na, integer m=2~5, represented by sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), sodium hydride (NaH), potassium hydride (KH), calcium hydride (CaH 2 ), sodium hydroxide (NaOH), potassium hydroxide (KOH), potassium carbonate (K 2 CO 3 ), sodium carbonate (Na 2 CO 3 ), potassium bicarbonate (KHCO 3 ) and sodium bicarbonate (NaHCO 3 ) at least one as a catalyst, using at least one of tetrahydrofuran, N,N-dimethylformamide, dichloromethane, chloroform, ethyl acetate and cyclohexane as a solvent to synthesize a carbon-containing A hybrid fluorosurfactant C with fluorine bond and carbon-hydrogen bond n f 2n+1 CH 2 CH 2 O(CH 2 ) m COONa, integer n=4~18, integer m=2~5 and C n f 2n+1 CH 2 CH 2 O(CH 2 ) m SO 3 Na, integer n=4~18, integer m=at least one of 2~5, hybrid fluorine-containing surfactant referred to as HFS

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