Surfactant oil-displacing agent and preparation method thereof

Abstract

The invention relates to the technical field of oil exploitation, in particular to a surfactant oil-displacing agent and a preparation method thereof.The surfactant oil-displacing agent is prepared from, by weight, 20-24% of composite surfactant, 6-8% of n-amyl alcohol, 3-4% of cyclohexane, 2-3% of stabilizer and the balance water; a composite precursor containing magnetic nanoparticles is taken as a core, and a reversible Diels-Alder structure graft modified surfactant is taken as a shell, so that the problem of insufficient high-temperature and high-salt resistance of an existing surfactant oil-displacing agent is solved, and meanwhile, the oil-displacing agent has a certain recovery characteristic due to the magnetic core of the oil-displacing agent.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum exploitation, and in particular to a surfactant oil-displacing agent and a preparation method thereof. Background Art

[0002] In order to increase crude oil production, chemical flooding is usually used to improve crude oil recovery. Surfactant flooding is a common flooding method. However, due to the high temperature and high salt characteristics of crude oil extraction, common surfactant flooding agents cannot meet the increasingly high technical requirements. Nanoparticle flooding, as an emerging flooding method, can overcome some of the shortcomings of conventional surfactant flooding. However, since its main component is metal or non-metallic nanoparticles, it is difficult to recover. Summary of the invention

[0003] The purpose of the present invention is to provide a surfactant oil-displacing agent and a preparation method thereof. By using a composite precursor containing magnetic nanoparticles as a core and a reversible Diels-Alder structure grafted modified surfactant as a shell, the problem of insufficient high temperature and high salt resistance of existing surfactant oil-displacing agents is solved. At the same time, its magnetic core also gives it certain recovery characteristics.

[0004] The object of the present invention can be achieved by the following technical scheme: A method for preparing a surfactant oil-displacing agent, comprising the following steps: weighing the following raw materials in weight percentage: 20-24% composite surfactant, 6-8% n-pentanol, 3-4% cyclohexane and 2-3% stabilizer, the balance being water, mixing the composite surfactant, n-pentanol, cyclohexane, stabilizer and water to prepare a surfactant oil-displacing agent; The stabilizer is DRKJ-09 stabilizer; The composite surfactant is prepared by the following steps: Step A1: 2,5-furan dimethanol and tetrahydrofuran are mixed, and under the conditions of stirring at a rate of 150-180 rpm and a temperature of 50° C., sodium hydroxide solution, epichlorohydrin and tetrabutylammonium bromide are added, and the mixture is reacted for 2-3 hours to obtain intermediate 1; intermediate 1, 2-aminoethanesulfonic acid, tetrahydrofuran and deionized water are mixed, and under the conditions of stirring at a rate of 120-150 rpm and a temperature of 60° C., sodium hydroxide solution is added to adjust the pH value to 9, and the mixture is reacted for 6-8 hours at a rate of 120-150 rpm and a temperature of 60° C. to obtain intermediate 2; The mass fraction of the sodium hydroxide solution used in the preparation process of intermediate 1 is 50%, and the amount ratio of 2,5-furan dimethanol, sodium hydroxide solution, epichlorohydrin and tetrabutylammonium bromide is 0.02-0.022 mol: 24-25 mL: 0.045-0.05 mol: 0.6-0.7 g; the mass fraction of the sodium hydroxide solution used in the preparation process of intermediate 2 is 30%, and the amount ratio of intermediate 1 and 2-aminoethanesulfonic acid is 0.02-0.022 mol: 0.045-0.048 mol; During the reaction, under the action of tetrabutylammonium bromide, the hydroxyl group in 2,5-furan dimethanol reacts with the epoxy group in epichlorohydrin to generate a hydroxyl group, and then under alkaline conditions, the hydroxyl group condenses with chlorine to form an epoxy group to obtain intermediate 1, and the epoxy group in intermediate 1 reacts with the amino group in 2-aminoethanesulfonic acid to form a secondary amine group to obtain intermediate 2; Step A2: allyl glycidyl ether, Custer platinum catalyst and deionized water are mixed, and under the conditions of stirring rate of 80-100 rpm and temperature of 60° C., heptamethyltrisiloxane is added with stirring, and the reaction is carried out for 5-6 hours to obtain intermediate 3; intermediate 2, intermediate 3 and deionized water are mixed, and under the conditions of stirring rate of 150-180 rpm and temperature of 80° C., sodium hydroxide solution is added to adjust the pH value to 8, and the reaction is carried out for 8-10 hours to obtain a modified surfactant; The dosage ratio of allyl glycidyl ether, Custer platinum catalyst and heptamethyl trisiloxane is 0.01-0.012 mol: 0.02-0.03 g: 0.011-0.012 mol; the mass fraction of sodium hydroxide solution is 30%, and the dosage ratio of intermediate 2 and intermediate 3 is 0.01-0.011 mol: 0.022-0.025 mol; During the reaction, under the action of Custer's platinum catalyst, the double bond in allyl glycidyl ether undergoes silylation with heptamethyltrisiloxane to obtain intermediate 3 containing an epoxy group. Then, under alkaline conditions, the epoxy group in intermediate 3 reacts with the secondary amine group in intermediate 2 to obtain a modified surfactant. Step A3: mixing the composite precursor, the modified surfactant, N,N'-(1,4-phenylene)bismaleimide and anisole, and reacting for 48 hours at a stirring rate of 150-180 rpm and a temperature of 60°C to obtain a composite surfactant; The ratio of the composite precursor, the modified surfactant and N,N'-(1,4-phenylene)bismaleimide is 0.5-0.52 g: 0.008-0.01 mol: 0.01-0.011 mol; During the reaction, the furan groups in the composite precursor and the modified surfactant react with the maleimide groups in N,N'-(1,4-phenylene)bismaleimide through Diels-Alder reaction, thereby forming a reversible DA structure to prepare a composite surfactant; The composite precursor is prepared by the following steps: Step B1: nickel nitrate hexahydrate, ferric chloride hexahydrate and deionized water are mixed, sodium hydroxide solution is added to adjust the pH value to 13, and the reaction is carried out for 1 hour at a stirring rate of 120-150 rpm and a temperature of 90° C. to obtain precursor 1, dicyclohexylcarbodiimide, N-hydroxysuccinimide and N,N-dimethylformamide are mixed, and acrylic acid is added at a stirring rate of 60-80 rpm and room temperature, and the reaction is carried out for 24 hours, and then precursor 1 and dimethyl sulfoxide are added, and the reaction is continued for 24 hours to obtain precursor 2; The mass fraction of the sodium hydroxide solution is 10%, the dosage ratio of nickel nitrate hexahydrate and ferric chloride hexahydrate is 3.4-3.6 g: 1.7-1.8 g; the dosage ratio of dicyclohexylcarbodiimide, N-hydroxysuccinimide, acrylic acid and precursor 1 is 0.07-0.08 g: 0.04-0.042 g: 0.02-0.024 mol: 0.04-0.05 g; During the reaction, nickel iron oxide is formed by a hydrothermal method to obtain precursor 1, and then under the action of dicyclohexylcarbodiimide and N-hydroxysuccinimide, the carboxyl group in acrylic acid combines with the hydroxyl group on the surface of precursor 1 to introduce a double bond to obtain precursor 2; Step B2: Vinyltrimethoxysilane, methanol and deionized water were mixed, hydrochloric acid solution was added to adjust the pH value to 2, and the reaction was carried out for 8-10 hours at a stirring rate of 200-240 rpm and a temperature of 60°C to obtain intermediate a, and precursor 2, intermediate a, tetrahydrofuran and polyethylene glycol were mixed and ultrasonically dispersed for 10 minutes, and azobisisobutyronitrile was added at a stirring rate of 80-100 rpm and a temperature of 60°C, and the reaction was carried out for 3-4 hours to obtain precursor 3; The mass fraction of the hydrochloric acid solution is 25%, the usage ratio of vinyltrimethoxysilane, methanol and deionized water is 28-32g: 30-31g: 8-9mL; the usage ratio of precursor 2, intermediate a, polyethylene glycol and azobisisobutyronitrile is 0.25-0.3g: 0.4-0.5g: 0.6-0.62g: 0.009-0.01g; During the reaction, under acidic conditions, vinyltrimethoxysilane is hydrolyzed to form a silsesquioxane structure with a terminal double bond, thereby obtaining an intermediate a. Then, under the condition of azobisisobutyronitrile as a catalyst, the double bond in the intermediate a reacts with the double bond in the precursor 2, thereby wrapping a layer of the intermediate a on the surface of the precursor 2, thereby obtaining a precursor 3. Step B3: Mix itaconic anhydride and toluene, stir at a stirring rate of 100-120 rpm, add furfurylamine, and react for 4-5 hours to obtain intermediate b, mix precursor 3, intermediate b and toluene and ultrasonically disperse for 10 minutes, stir at a stirring rate of 80-100 rpm, and add azobisisobutyronitrile at 60°C, and react for 12 hours to obtain a composite precursor; The ratio of itaconic anhydride to furfurylamine is 0.04-0.041 mol: 0.041-0.042 mol; the ratio of precursor 3, intermediate b and azobisisobutyronitrile is 0.5-0.52 g: 0.08-0.09 mol: 0.1-0.11 g; During the reaction, the anhydride group in itaconic anhydride reacts with the amino group in furfurylamine to form an amide structure and generate a carboxyl group to obtain intermediate b. Under the action of azobisisobutyronitrile, the double bond in intermediate b and the unreacted double bond in precursor 3 copolymerize to obtain a composite precursor. Beneficial effects of the invention: The invention discloses a surfactant oil-displacing agent and a preparation method thereof. By using a composite precursor containing magnetic nanoparticles as a core and a reversible Diels-Alder structure grafted modified surfactant as a shell, the problem of insufficient high temperature and high salt resistance of the existing surfactant oil-displacing agent is solved, and at the same time, its magnetic core also enables it to have certain recovery characteristics; during the use of the surfactant oil-displacing agent, due to the presence of its magnetic core, it can penetrate into the reservoir position that conventional chemical oil-displacing agents cannot reach under the action of an external magnetic field, thereby improving the crude oil recovery rate, and under the high temperature environment of the reservoir, its reversible Diels-Alder structure breaks, thereby releasing the external composite surfactant, and because the surfactant itself contains a trisiloxane structure and a sulfonate structure, it can better improve the fluid and the original The interfacial tension between the oil and the surface of the material and the wettability of the storage rock are changed, thereby improving the crude oil recovery rate. At the same time, the existence of its structure also gives it good temperature resistance. And because it is released deep into the reservoir and then plays an oil recovery role, this also avoids the decrease in oil recovery effect caused by the combination of surfactants with cations in high-mineralization water to a certain extent, thereby reflecting a good salt resistance effect. At the same time, during the recovery process, due to its reversible characteristics, the modified surfactant can be recovered along with the magnetic core, thereby improving the reuse rate. After releasing the modified surfactant, due to the characteristics of the nickel iron oxide core itself, it can undergo spin flipping or spin oscillation inside the fluid to generate heat energy, thereby overcoming the van der Waals interaction at the oil-water interface. Due to the characteristics of its silsesquioxane structure itself, it allows them to combine with each other to reduce the oil-water interfacial tension, thereby improving the crude oil recovery rate. DETAILED DESCRIPTION

[0005] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0006] Example 1 A method for preparing a surfactant oil-displacing agent comprises the following steps: weighing the following raw materials in weight percentage: 20% composite surfactant, 6% n-pentanol, 3% cyclohexane and 2% commercially available DRKJ-09 stabilizer, the remainder being water, mixing the composite surfactant, n-pentanol, cyclohexane, stabilizer and water to prepare a surfactant oil-displacing agent; The composite surfactant is prepared by the following steps: Step A1: 2,5-furan dimethanol and tetrahydrofuran are mixed, and under the conditions of a stirring rate of 150 rpm and a temperature of 50° C., sodium hydroxide solution, epichlorohydrin and tetrabutylammonium bromide are added with stirring, and the mixture is reacted for 2 h to obtain intermediate 1; intermediate 1, 2-aminoethanesulfonic acid, tetrahydrofuran and deionized water are mixed, and under the conditions of stirring, sodium hydroxide solution is added to adjust the pH value to 9, and the mixture is reacted for 6 h at a stirring rate of 120 rpm and a temperature of 60° C. to obtain intermediate 2; The mass fraction of the sodium hydroxide solution used in the preparation process of intermediate 1 is 50%, and the amount ratio of 2,5-furan dimethanol, sodium hydroxide solution, epichlorohydrin and tetrabutylammonium bromide is 0.02 mol: 24 mL: 0.045 mol: 0.6-0.7 g; the mass fraction of the sodium hydroxide solution used in the preparation process of intermediate 2 is 30%, and the amount ratio of intermediate 1 and 2-aminoethanesulfonic acid is 0.02 mol: 0.045 mol; Step A2: allyl glycidyl ether, Custer platinum catalyst and deionized water were mixed, and under the conditions of stirring rate of 80 rpm and temperature of 60° C., heptamethyltrisiloxane was added with stirring, and the mixture was reacted for 5 h to obtain intermediate 3; intermediate 2, intermediate 3 and deionized water were mixed, and under the conditions of stirring rate of 150 rpm and temperature of 80° C., sodium hydroxide solution was added to adjust the pH value to 8, and the mixture was reacted for 8 h to obtain a modified surfactant; The dosage ratio of allyl glycidyl ether, Custer platinum catalyst and heptamethyltrisiloxane is 0.01 mol: 0.02 g: 0.011 mol; the mass fraction of sodium hydroxide solution is 30%, and the dosage ratio of intermediate 2 and intermediate 3 is 0.01 mol: 0.022 mol; Step A3: mixing the composite precursor, the modified surfactant, N,N'-(1,4-phenylene)bismaleimide and anisole, and reacting them for 48 hours at a stirring rate of 150 rpm and a temperature of 60°C to obtain a composite surfactant; The ratio of the composite precursor, modified surfactant and N,N'-(1,4-phenylene)bismaleimide is 0.5g:0.008mol:0.01mol; The composite precursor is prepared by the following steps: Step B1: nickel nitrate hexahydrate, ferric chloride hexahydrate and deionized water are mixed, sodium hydroxide solution is added to adjust the pH value to 13, and the mixture is reacted for 1 hour at a stirring rate of 120 rpm and a temperature of 90° C. to obtain precursor 1, dicyclohexylcarbodiimide, N-hydroxysuccinimide and N,N-dimethylformamide are mixed, and acrylic acid is added at a stirring rate of 60 rpm and room temperature, and the mixture is reacted for 24 hours, and then precursor 1 and dimethyl sulfoxide are added, and the reaction is continued for 24 hours to obtain precursor 2; The mass fraction of sodium hydroxide solution is 10%, the usage ratio of nickel nitrate hexahydrate and ferric chloride hexahydrate is 3.4g:1.7g; the usage ratio of dicyclohexylcarbodiimide, N-hydroxysuccinimide, acrylic acid and precursor 1 is 0.07g:0.04g:0.02mol:0.04g; Step B2: Vinyltrimethoxysilane, methanol and deionized water were mixed, hydrochloric acid solution was added to adjust the pH value to 2, and the reaction was carried out at a stirring rate of 200 rpm and a temperature of 60°C for 8 hours to obtain intermediate a, and precursor 2, intermediate a, tetrahydrofuran and polyethylene glycol were mixed and ultrasonically dispersed for 10 minutes, and azobisisobutyronitrile was added at a stirring rate of 80 rpm and a temperature of 60°C, and the reaction was carried out for 3 hours to obtain precursor 3; The mass fraction of hydrochloric acid solution is 25%, the usage ratio of vinyltrimethoxysilane, methanol and deionized water is 28g:30g:8mL; the usage ratio of precursor 2, intermediate a, polyethylene glycol and azobisisobutyronitrile is 0.25g:0.4g:0.6g:0.009g; Step B3: Itaconic anhydride and toluene were mixed, stirred at a stirring rate of 100 rpm, and furfurylamine was added, and the reaction was carried out for 4 hours to obtain intermediate b. Precursor 3, intermediate b and toluene were mixed and ultrasonically dispersed for 10 minutes, and azobisisobutyronitrile was added at a stirring rate of 80 rpm and a temperature of 60°C, and the reaction was carried out for 12 hours to obtain a composite precursor; The usage ratio of itaconic anhydride and furfurylamine is 0.04 mol:0.041 mol; the usage ratio of precursor 3, intermediate b and azobisisobutyronitrile is 0.5 g:0.08 mol:0.1 g.

[0007] Example 2 A method for preparing a surfactant oil-displacing agent comprises the following steps: weighing the following raw materials in weight percentage: 24% composite surfactant, 6% n-pentanol, 4% cyclohexane and 2% commercially available DRKJ-09 stabilizer, the balance being water, mixing the composite surfactant, n-pentanol, cyclohexane, stabilizer and water to prepare a surfactant oil-displacing agent; The composite surfactant is prepared by the following steps: Step A1: 2,5-furan dimethanol and tetrahydrofuran are mixed, and under the conditions of a stirring rate of 180 rpm and a temperature of 50° C., sodium hydroxide solution, epichlorohydrin and tetrabutylammonium bromide are added with stirring, and the mixture is reacted for 2 h to obtain intermediate 1; intermediate 1, 2-aminoethanesulfonic acid, tetrahydrofuran and deionized water are mixed, and under the conditions of stirring, sodium hydroxide solution is added to adjust the pH value to 9, and the mixture is reacted for 8 h at a stirring rate of 120 rpm and a temperature of 60° C. to obtain intermediate 2; The mass fraction of the sodium hydroxide solution used in the preparation process of intermediate 1 is 50%, and the amount ratio of 2,5-furan dimethanol, sodium hydroxide solution, epichlorohydrin and tetrabutylammonium bromide is 0.022 mol: 24 mL: 0.05 mol: 0.6 g; the mass fraction of the sodium hydroxide solution used in the preparation process of intermediate 2 is 30%, and the amount ratio of intermediate 1 and 2-aminoethanesulfonic acid is 0.02 mol: 0.048 mol; Step A2: allyl glycidyl ether, Custer platinum catalyst and deionized water were mixed, and heptamethyltrisiloxane was added under stirring at a rate of 100 rpm and a temperature of 60°C, and the mixture was reacted for 5 hours to obtain intermediate 3; intermediate 2, intermediate 3 and deionized water were mixed, and sodium hydroxide solution was added to adjust the pH value to 8 under stirring at a rate of 180 rpm and a temperature of 80°C, and the mixture was reacted for 8 hours to obtain a modified surfactant; The dosage ratio of allyl glycidyl ether, Custer platinum catalyst and heptamethyltrisiloxane is 0.012 mol: 0.02 g: 0.012 mol; the mass fraction of sodium hydroxide solution is 30%, and the dosage ratio of intermediate 2 and intermediate 3 is 0.011 mol: 0.022 mol; Step A3: mixing the composite precursor, the modified surfactant, N,N'-(1,4-phenylene)bismaleimide and anisole, and reacting them for 48 hours at a stirring rate of 150 rpm and a temperature of 60°C to obtain a composite surfactant; The ratio of the composite precursor, modified surfactant and N,N'-(1,4-phenylene)bismaleimide is 0.52g:0.008mol:0.011mol; The composite precursor is prepared by the following steps: Step B1: nickel nitrate hexahydrate, ferric chloride hexahydrate and deionized water are mixed, sodium hydroxide solution is added to adjust the pH value to 13, and the mixture is reacted for 1 hour at a stirring rate of 120 rpm and a temperature of 90° C. to obtain precursor 1, dicyclohexylcarbodiimide, N-hydroxysuccinimide and N,N-dimethylformamide are mixed, and acrylic acid is added at a stirring rate of 80 rpm and room temperature, and the mixture is reacted for 24 hours, and then precursor 1 and dimethyl sulfoxide are added, and the reaction is continued for 24 hours to obtain precursor 2; The mass fraction of sodium hydroxide solution is 10%, the usage ratio of nickel nitrate hexahydrate and ferric chloride hexahydrate is 3.6g:1.7g; the usage ratio of dicyclohexylcarbodiimide, N-hydroxysuccinimide, acrylic acid and precursor 1 is 0.07g:0.042g:0.02mol:0.05g; Step B2: Vinyltrimethoxysilane, methanol and deionized water were mixed, hydrochloric acid solution was added to adjust the pH value to 2, and the reaction was carried out for 10 hours at a stirring rate of 200 rpm and a temperature of 60°C to obtain intermediate a. Precursor 2, intermediate a, tetrahydrofuran and polyethylene glycol were mixed and ultrasonically dispersed for 10 minutes, and azobisisobutyronitrile was added at a stirring rate of 100 rpm and a temperature of 60°C, and the reaction was carried out for 3 hours to obtain precursor 3; The mass fraction of hydrochloric acid solution is 25%, the usage ratio of vinyltrimethoxysilane, methanol and deionized water is 32g:31g:9mL; the usage ratio of precursor 2, intermediate a, polyethylene glycol and azobisisobutyronitrile is 0.3g:0.4g:0.6g:0.01g; Step B3: Itaconic anhydride and toluene were mixed, stirred at a stirring rate of 100 rpm, at room temperature, and furfurylamine was added, and the mixture was reacted for 5 hours to obtain intermediate b; precursor 3, intermediate b and toluene were mixed and ultrasonically dispersed for 10 minutes, stirred at a stirring rate of 100 rpm, at a temperature of 60°C, and azobisisobutyronitrile was added, and the mixture was reacted for 12 hours to obtain a composite precursor; The usage ratio of itaconic anhydride and furfurylamine is 0.041 mol:0.042 mol; the usage ratio of precursor 3, intermediate b and azobisisobutyronitrile is 0.52 g:0.09 mol:0.1 g.

[0008] Example 3 A method for preparing a surfactant oil-displacing agent comprises the following steps: weighing the following raw materials in weight percentage: 24% composite surfactant, 8% n-pentanol, 4% cyclohexane and 3% commercially available DRKJ-09 stabilizer, the balance being water, mixing the composite surfactant, n-pentanol, cyclohexane, stabilizer and water to prepare a surfactant oil-displacing agent; The composite surfactant is prepared by the following steps: Step A1: 2,5-furan dimethanol and tetrahydrofuran are mixed, and under the conditions of a stirring rate of 180 rpm and a temperature of 50° C., sodium hydroxide solution, epichlorohydrin and tetrabutylammonium bromide are added with stirring, and the mixture is reacted for 3 h to obtain intermediate 1; intermediate 1, 2-aminoethanesulfonic acid, tetrahydrofuran and deionized water are mixed, and under the conditions of stirring, sodium hydroxide solution is added to adjust the pH value to 9, and the mixture is reacted for 8 h at a stirring rate of 150 rpm and a temperature of 60° C. to obtain intermediate 2; The mass fraction of the sodium hydroxide solution used in the preparation process of intermediate 1 is 50%, and the amount ratio of 2,5-furan dimethanol, sodium hydroxide solution, epichlorohydrin and tetrabutylammonium bromide is 0.022 mol: 25 mL: 0.05 mol: 0.6-0.7 g; the mass fraction of the sodium hydroxide solution used in the preparation process of intermediate 2 is 30%, and the amount ratio of intermediate 1 and 2-aminoethanesulfonic acid is 0.022 mol: 0.048 mol; Step A2: allyl glycidyl ether, Custer platinum catalyst and deionized water were mixed, and under the conditions of stirring rate of 100 rpm and temperature of 60° C., heptamethyltrisiloxane was added with stirring, and the mixture was reacted for 6 h to obtain intermediate 3; intermediate 2, intermediate 3 and deionized water were mixed, and under the conditions of stirring rate of 180 rpm and temperature of 80° C., sodium hydroxide solution was added to adjust the pH value to 8, and the mixture was reacted for 10 h to obtain a modified surfactant; The dosage ratio of allyl glycidyl ether, Custer platinum catalyst and heptamethyltrisiloxane is 0.012 mol: 0.03 g: 0.012 mol; the mass fraction of sodium hydroxide solution is 30%, and the dosage ratio of intermediate 2 and intermediate 3 is 0.011 mol: 0.025 mol; Step A3: mixing the composite precursor, the modified surfactant, N,N'-(1,4-phenylene)bismaleimide and anisole, and reacting for 48 hours at a stirring rate of 180 rpm and a temperature of 60°C to obtain a composite surfactant; The ratio of the composite precursor, modified surfactant and N,N'-(1,4-phenylene)bismaleimide is 0.52g:0.01mol:0.011mol; The composite precursor is prepared by the following steps: Step B1: nickel nitrate hexahydrate, ferric chloride hexahydrate and deionized water are mixed, sodium hydroxide solution is added to adjust the pH value to 13, and the mixture is reacted for 1 hour at a stirring rate of 150 rpm and a temperature of 90° C. to obtain precursor 1, dicyclohexylcarbodiimide, N-hydroxysuccinimide and N,N-dimethylformamide are mixed, and acrylic acid is added at a stirring rate of 80 rpm and room temperature, and the mixture is reacted for 24 hours, and then precursor 1 and dimethyl sulfoxide are added, and the reaction is continued for 24 hours to obtain precursor 2; The mass fraction of sodium hydroxide solution is 10%, the usage ratio of nickel nitrate hexahydrate and ferric chloride hexahydrate is 3.6g:1.8g; the usage ratio of dicyclohexylcarbodiimide, N-hydroxysuccinimide, acrylic acid and precursor 1 is 0.08g:0.042g:0.024mol:0.05g; Step B2: Vinyltrimethoxysilane, methanol and deionized water were mixed, hydrochloric acid solution was added to adjust the pH value to 2, and the reaction was carried out at a stirring rate of 240 rpm and a temperature of 60°C for 10 hours to obtain intermediate a. Precursor 2, intermediate a, tetrahydrofuran and polyethylene glycol were mixed and ultrasonically dispersed for 10 minutes, and azobisisobutyronitrile was added at a stirring rate of 100 rpm and a temperature of 60°C, and the reaction was carried out for 4 hours to obtain precursor 3; The mass fraction of hydrochloric acid solution is 25%, the usage ratio of vinyltrimethoxysilane, methanol and deionized water is 32g:31g:9mL; the usage ratio of precursor 2, intermediate a, polyethylene glycol and azobisisobutyronitrile is 0.3g:0.5g:0.62g:0.01g; Step B3: Itaconic anhydride and toluene were mixed, stirred at a stirring rate of 120 rpm, and furfurylamine was added, and the reaction was carried out for 5 hours to obtain intermediate b. Precursor 3, intermediate b and toluene were mixed and ultrasonically dispersed for 10 minutes, and azobisisobutyronitrile was added at a stirring rate of 100 rpm and a temperature of 60°C, and the reaction was carried out for 12 hours to obtain a composite precursor; The usage ratio of itaconic anhydride and furfurylamine is 0.041 mol:0.042 mol; the usage ratio of precursor 3, intermediate b and azobisisobutyronitrile is 0.52 g:0.09 mol:0.11 g.

[0009] Comparative Example 1 Compared with Example 3, this comparative example is different in that allyl glycidyl ether in the preparation process of the composite surfactant in Example 3 is replaced by 1,2-epoxyhexane, and the other steps are the same.

[0010] Comparative Example 2 Compared with Example 3, this comparative example replaces the composite surfactant in the preparation process of the surfactant oil-displacing agent in Example 3 with a mixture of the composite precursor in Example 3 and the modified surfactant in Example 3, and the other steps are the same, wherein the usage ratio of the composite precursor to the modified surfactant is 0.52g:0.01mol.

[0011] Comparative Example 3 Compared with Example 3, this comparative example is different in that the precursor 3 in the preparation process of the composite precursor in Example 3 is replaced by the precursor 2, and the other steps are the same.

[0012] Take the surfactant oil-displacing agents prepared in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2 and Comparative Example 3, mix 20g of the surfactant oil-displacing agent and 1000mL of deionized water to prepare an oil-displacing system, refer to SY / T 5153-2007, measure the wettability of its reservoir rock, and determine its performance by the change in wetting angle, refer to GB / T 6541-86, test its surface tension at a temperature of 120°C, and then conduct a core flooding experiment, set a 500Gs horizontal uniform magnetic field in the direction parallel to the flow of the core, and add 10000ppm of sodium chloride, and heat the oil-displacing agent system to 120°C before injection, calculate its recovery rate, and test its recovery rate under the condition of no magnetic field application, recover it after use and repeat the test, measure its recovery rate after repeating the experiment three times, and calculate its performance retention rate. The test results are as follows: Test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Wetting angle change (°) 81.95 82.57 84.19 72.18 83.64 80.47 Surface tension (mN / m) 25.66 24.10 23.24 31.42 24.47 26.40 500Gs magnetic field recovery rate (%) 78.31 80.66 81.92 65.90 72.11 74.63 Recovery rate without magnetic field application (%) 52.06 57.80 58.41 42.28 48.60 51.72 Performance retention rate (%) 72.45 73.51 75.24 74.92 51.67 70.38 It can be seen from the test results in the table shown that when Example 1, Example 2 and Example 3 are compared with Comparative Example 1, Comparative Example 2 and Comparative Example 3, allyl glycidyl ether in the preparation process of the composite surfactant of Example 3 is replaced with 1,2-epoxyhexane. Due to the lack of trisiloxane structure, its performance is significantly reduced. Comparative Example 2 replaces the composite surfactant in the preparation process of the surfactant oil-displacing agent of Example 3 with a mixture of a composite precursor and a modified surfactant. Due to the lack of a reversible structure, its performance is significantly reduced. Comparative Example 3 replaces Precursor 3 with Precursor 2 in the preparation process of the composite precursor of Example 3. Due to the lack of a silsesquioxane structure, its performance is significantly reduced.

[0013] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0014] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A method for preparing a surfactant oil-displacing agent, characterized in that: The method comprises the following steps: weighing the following raw materials in weight percentage: 20-24% of a composite surfactant, 6-8% of n-pentanol, 3-4% of cyclohexane and 2-3% of a stabilizer, with the remainder being water, and mixing the composite surfactant, n-pentanol, cyclohexane, the stabilizer and water to prepare a surfactant oil displacement agent; The stabilizer is DRKJ-09 stabilizer; The composite surfactant is prepared by the following steps: Step A1: 2,5-furan dimethanol and tetrahydrofuran are mixed, and under the conditions of stirring at a rate of 150-180 rpm and a temperature of 50° C., sodium hydroxide solution, epichlorohydrin and tetrabutylammonium bromide are added, and the mixture is reacted for 2-3 hours to obtain intermediate 1; intermediate 1, 2-aminoethanesulfonic acid, tetrahydrofuran and deionized water are mixed, and under the conditions of stirring at a rate of 120-150 rpm and a temperature of 60° C., sodium hydroxide solution is added to adjust the pH value to 9, and the mixture is reacted for 6-8 hours at a rate of 120-150 rpm and a temperature of 60° C. to obtain intermediate 2; Step A2: allyl glycidyl ether, Custer platinum catalyst and deionized water are mixed, and under the conditions of stirring rate of 80-100 rpm and temperature of 60° C., heptamethyltrisiloxane is added with stirring, and the reaction is carried out for 5-6 hours to obtain intermediate 3; intermediate 2, intermediate 3 and deionized water are mixed, and under the conditions of stirring rate of 150-180 rpm and temperature of 80° C., sodium hydroxide solution is added to adjust the pH value to 8, and the reaction is carried out for 8-10 hours to obtain a modified surfactant; Step A3: The composite precursor, the modified surfactant, N,N'-(1,4-phenylene)bismaleimide and anisole were mixed, and the mixture was reacted for 48 hours at a stirring rate of 150-180 rpm and a temperature of 60°C to obtain a composite surfactant.

2. The method for preparing a surfactant oil-displacing agent according to claim 1, wherein: In step A1: the mass fraction of the sodium hydroxide solution used in the preparation process of intermediate 1 is 50%, and the amount ratio of 2,5-furan dimethanol, sodium hydroxide solution, epichlorohydrin and tetrabutylammonium bromide is 0.02-0.022 mol: 24-25 mL: 0.045-0.05 mol: 0.6-0.7 g; the mass fraction of the sodium hydroxide solution used in the preparation process of intermediate 2 is 30%, and the amount ratio of intermediate 1 and 2-aminoethanesulfonic acid is 0.02-0.022 mol: 0.045-0.048 mol.

3. The method for preparing a surfactant oil-displacing agent according to claim 1, characterized in that: In step A2, the amount ratio of allyl glycidyl ether, Custer platinum catalyst and heptamethyltrisiloxane is 0.01-0.012 mol: 0.02-0.03 g: 0.011-0.012 mol; the mass fraction of the sodium hydroxide solution is 30%, and the amount ratio of intermediate 2 and intermediate 3 is 0.01-0.011 mol: 0.022-0.025 mol.

4. The method for preparing a surfactant oil-displacing agent according to claim 1, wherein: In step A3: the ratio of the composite precursor, the modified surfactant and N,N'-(1,4-phenylene)bismaleimide is 0.5-0.52 g: 0.008-0.01 mol: 0.01-0.011 mol.

5. The method for preparing a surfactant oil-displacing agent according to claim 1, characterized in that: The composite precursor is prepared by the following steps: Step B1: nickel nitrate hexahydrate, ferric chloride hexahydrate and deionized water are mixed, sodium hydroxide solution is added to adjust the pH value to 13, and the reaction is carried out for 1 hour at a stirring rate of 120-150 rpm and a temperature of 90° C. to obtain precursor 1, dicyclohexylcarbodiimide, N-hydroxysuccinimide and N,N-dimethylformamide are mixed, and acrylic acid is added at a stirring rate of 60-80 rpm and room temperature, and the reaction is carried out for 24 hours, and then precursor 1 and dimethyl sulfoxide are added, and the reaction is continued for 24 hours to obtain precursor 2; Step B2: Vinyltrimethoxysilane, methanol and deionized water were mixed, hydrochloric acid solution was added to adjust the pH value to 2, and the reaction was carried out for 8-10 hours at a stirring rate of 200-240 rpm and a temperature of 60°C to obtain intermediate a, and precursor 2, intermediate a, tetrahydrofuran and polyethylene glycol were mixed and ultrasonically dispersed for 10 minutes, and azobisisobutyronitrile was added at a stirring rate of 80-100 rpm and a temperature of 60°C, and the reaction was carried out for 3-4 hours to obtain precursor 3; Step B3: Mix itaconic anhydride and toluene, stir and add furfurylamine at a stirring rate of 100-120 rpm and room temperature, and react for 4-5 hours to obtain intermediate b. Mix precursor 3, intermediate b and toluene and ultrasonically disperse for 10 minutes, stir and add azobisisobutyronitrile at a stirring rate of 80-100 rpm and a temperature of 60°C, and react for 12 hours to obtain a composite precursor.

6. The method for preparing a surfactant oil-displacing agent according to claim 5, characterized in that: In step B1: the mass fraction of the sodium hydroxide solution is 10%, the amount ratio of nickel nitrate hexahydrate and ferric chloride hexahydrate is 3.4-3.6g:1.7-1.8g; the amount ratio of dicyclohexylcarbodiimide, N-hydroxysuccinimide, acrylic acid and precursor 1 is 0.07-0.08g:0.04-0.042g:0.02-0.024mol:0.04-0.05g.

7. The method for preparing a surfactant oil-displacing agent according to claim 5, characterized in that: In step B2: the mass fraction of the hydrochloric acid solution is 25%, the amount ratio of vinyltrimethoxysilane, methanol and deionized water is 28-32g: 30-31g: 8-9mL; the amount ratio of precursor 2, intermediate a, polyethylene glycol and azobisisobutyronitrile is 0.25-0.3g: 0.4-0.5g: 0.6-0.62g: 0.009-0.01g.

8. The method for preparing a surfactant oil-displacing agent according to claim 5, characterized in that: In step B3: the ratio of itaconic anhydride to furfurylamine is 0.04-0.041 mol: 0.041-0.042 mol; the ratio of precursor 3, intermediate b and azobisisobutyronitrile is 0.5-0.52 g: 0.08-0.09 mol: 0.1-0.11 g.

9. A surfactant oil-displacing agent, characterized in that: Prepared according to any one of the preparation methods described in claims 1-8.