Surfactant for oil extraction in oil field and preparation method thereof

Abstract

The invention relates to the technical field of surfactants for oil field oil extraction, in particular to a surfactant for oil field oil extraction and a preparation method thereof.The surfactant is prepared from, by weight, 15-20 parts of polymer surfactants, 8-12 parts of enhancing auxiliaries, 6-8 parts of temperature-sensitive microspheres and 80-90 parts of water, the problems that an existing surfactant for oil extraction in an oil field is insufficient in activity and poor in effect are solved by compounding a high-molecular surfactant, a reinforcing auxiliary agent containing a hyperbranched structure and temperature-sensitive microspheres loaded with microorganisms, and meanwhile, the surfactant has a certain temperature-sensitive characteristic and can play a role in the deep position of an oil layer to form a plugging and flooding composite effect; therefore, the crude oil recovery rate of surfactant flooding can be well improved.

Description

Technical Field

[0001] The invention relates to the technical field of surfactants for oil field production, in particular to surfactants for oil field production and a preparation method thereof. Background Art

[0002] Surfactant flooding, as an important technology to improve crude oil recovery, has been widely used. Most of the surfactants used on the market are single-chain surfactants or polymer surfactants. Polymer surfactants have good solubilizing, thickening, dispersing and flocculating effects, but it is difficult for them to form a stable layer at the interface, resulting in their surface activity being weaker than traditional surfactants. The surface tension takes a long time to reach a constant value, while single-chain surfactants are difficult to arrange more tightly at the interface or in molecular aggregates, resulting in their relatively low surface activity. They each have their own advantages and disadvantages and can no longer meet the increasing technical requirements in the oil field production process. Summary of the invention

[0003] The purpose of the present invention is to provide a surfactant for oil field production and a preparation method thereof. By compounding a polymer surfactant, an enhancement auxiliary agent containing a hyperbranched structure and a thermosensitive microsphere loaded with microorganisms, the problem of insufficient activity and poor effect of the existing surfactant for oil field production is solved. At the same time, it also has certain temperature-sensitive properties, so that it can play a role in the deep oil layer, forming a plugging and flooding composite effect, thereby better improving the crude oil recovery rate of surfactant flooding.

[0004] The object of the present invention can be achieved by the following technical scheme: a method for preparing a surfactant for oil field oil production, comprising the following steps: weighing the following raw materials in parts by weight: 15-20 parts of a polymer surfactant, 8-12 parts of an enhancing auxiliary agent, 6-8 parts of a thermosensitive microsphere and 80-90 parts of water, mixing the polymer surfactant, the enhancing auxiliary agent, the thermosensitive microsphere and the water to prepare a surfactant for oil field oil production; The polymer surfactant is Sinobao S504 polymer surfactant; The reinforcing aid is prepared by the following steps: Step A1: epichlorohydrin and potassium carbonate are mixed, stirred at a stirring rate of 120-150 rpm and a temperature of 70° C., thioctic acid is added, and the mixture is reacted for 24 hours to obtain a branched monomer; the branched monomer, tributylphosphine and anhydrous ethanol are mixed, stirred at a stirring rate of 150-180 rpm and a temperature of 70° C., the mixture is reacted for 24 hours, epichlorohydrin and sodium hydroxide solution are added, and the mixture is reacted for 6-8 hours to obtain a hyperbranched polymer; The amount ratio of epichlorohydrin, potassium carbonate and thioctic acid used in the preparation process of the branched monomer is 0.4-0.5 mol: 0.35-0.4 mol: 0.25-0.3 mol; the mass fraction of the sodium hydroxide solution used in the preparation process of the hyperbranched polymer is 10%, and the amount ratio of the branched monomer, tributylphosphine, epichlorohydrin and sodium hydroxide solution is 2.6-3 g: 5-6 g: 0.6-0.7 mol: 25-30 mL; During the reaction, lipoic acid reacts with epichlorohydrin under the action of potassium carbonate to obtain a branched monomer containing a disulfide bond and an epoxy group, and then under the action of tributylphosphine, the disulfide bond is reduced to a thiol group, and a thioether structure is formed through the reaction of the thiol group and the epoxy group, thereby self-polymerizing to form a hyperbranched structure, and then epichlorohydrin is added for end-capping, and under the condition of a sodium hydroxide solution, a chlorine-terminated hyperbranched polymer is obtained; Step A2: nicotinic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole and dichloromethane are mixed, stirred at a stirring rate of 240-260 rpm and room temperature, and octadecylamine is added, and the mixture is reacted for 12-14 hours to obtain an intermediate, and the intermediate, a hyperbranched polymer and toluene are mixed, and the mixture is reacted for 24 hours at a stirring rate of 150-180 rpm and a temperature of 110° C. to obtain a reinforcing agent; The ratio of nicotinic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole and octadecylamine is 0.1-0.12 mol: 5 g: 6 g: 0.1-0.12 mol, and the ratio of intermediate and hyperbranched polymer is 0.2-0.3 mol: 7-8 g: During the reaction, under the action of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1-hydroxybenzotriazole, the carboxyl group in nicotinic acid reacts with the amino group in octadecylamine to form an amide group to obtain an intermediate, and the pyridine ring in the intermediate then reacts with the terminal chlorine in the hyperbranched polymer to form a pyridinium salt structure to obtain a reinforcing agent; The temperature-sensitive microspheres are prepared by the following steps: Step B1: Tetramethoxysilane, deionized water and hydrochloric acid solution are mixed, stirred at a stirring rate of 80-120 rpm and room temperature for 1 hour, 3-aminopropyltrimethoxysilane is added, and stirring is continued for 1.5-2 hours, chitosan, deionized water and acetic acid solution are mixed and added, stirred at a stirring rate of 400-500 rpm and room temperature for 2 hours to obtain a water system, soybean oil and Span 80 are mixed, stirred at a stirring rate of 240-300 rpm and a temperature of 35°C, and the water system is added and stirred for 0.5 hours to obtain an emulsion system; The mass fraction of hydrochloric acid solution is 35%, the mass fraction of acetic acid solution is 2%, the dosage ratio of tetramethoxysilane, 3-aminopropyltrimethoxysilane, hydrochloric acid solution, chitosan and acetic acid solution is 0.5-0.8mL: 0.2-0.3mL: 0.02-0.03mL: 0.03-0.04g: 1-1.5mL; the dosage ratio of soybean oil, Span 80 and water system is 9-11mL: 0.1-0.2g: 1.2-1.4mL; During the reaction, tetramethoxysilane and 3-aminopropyltrimethoxysilane are hydrolyzed and condensed in a hydrochloric acid solution, and then mixed with chitosan to form a water system in the form of a sol, and the water system is dropped into a mixed system of soybean oil and Span 80 to obtain an emulsion system; Step B2: the emulsion system and the glutaraldehyde solution are mixed, and the reaction is carried out for 3-4 hours at a stirring rate of 80-120 rpm and a temperature of 45° C., and then the petroleum hydrocarbon degradation bacterial suspension is added and the reaction is continued for 4-5 hours to obtain loaded microspheres; The mass fraction of glutaraldehyde solution is 4%, the strain in the petroleum hydrocarbon degrading bacterial suspension is Bacillus cereus3096-3, the volume ratio of bacterial solution to culture medium is 5mL:95mL, the dosage ratio of petroleum hydrocarbon, sodium chloride, sodium dihydrogen phosphate, potassium dihydrogen phosphate, potassium chloride, magnesium sulfate, iron sulfate, manganese sulfate, zinc sulfate, copper sulfate, ammonium sulfate and deionized water in the culture medium is 10mL:28g:2g:2g:1g:1g:0.3g:0.3g:0.6g:0.7g:1g:1000mL, and the dosage ratio of emulsion system, glutaraldehyde solution and petroleum hydrocarbon degrading bacterial suspension is 10-11.5mL:30-35mL:8-10mL: During the reaction, glutaraldehyde reacts with amino groups in chitosan and amino groups in 3-aminopropyltrimethoxysilane in the emulsion system to form cross-linked microspheres, and then glutaraldehyde is used to fix petroleum hydrocarbon-degrading bacteria on the microspheres to obtain loaded microspheres. Step B3: Cyclohexane, Span 80 and Tween 80 were mixed, stirred at a stirring rate of 240-260 rpm and a temperature of 30°C for 30 minutes, and then the loaded microspheres were added and stirred for 15 minutes to obtain an oil phase system, sodium alginate solution, calcium chloride and sodium hydroxide were mixed, stirred at a stirring rate of 120-140 rpm and room temperature for 30 minutes, and then added to the oil phase system, stirred at a stirring rate of 80-100 rpm and a temperature of 60°C for 2 hours to obtain thermosensitive microspheres; The dosage ratio of cyclohexane, Span 80, Tween 80 and loaded microspheres is 75-85mL: 5.5-6g: 2.5-3g: 0.6-0.7g; the mass fraction of sodium alginate solution is 1.5%, and the dosage ratio of sodium alginate solution, calcium chloride, sodium hydroxide and oil phase system is 35-40mL: 1.2-1.5g: 0.8-1.2g: 65-70mL; During the reaction, a temperature-sensitive calcium alginate film is formed on the surface of the loaded microspheres by the ion gel method through the reaction between sodium alginate and calcium ions and the hydrogen bonding between sodium alginate and the loaded microspheres containing chitosan, thereby obtaining temperature-sensitive microspheres. Beneficial effects of the invention: The invention discloses a surfactant for oilfield production and a preparation method thereof. By compounding a polymer surfactant, an enhancement auxiliary agent containing a hyperbranched structure and a thermosensitive microsphere loaded with microorganisms, the problem of insufficient activity and poor effect of the existing surfactant for oilfield production is solved. At the same time, the surfactant also has certain thermosensitive properties, so that it can play a role in the deep oil layer to form a plugging and flooding composite effect, thereby better improving the crude oil recovery rate of surfactant flooding. During the use of the surfactant for oilfield production, since the enhancement auxiliary agent contains a hyperbranched structure and is grafted with a long-chain alkane with a pyridinium structure at the end, it embodies certain surfactant characteristics. At the same time, since it contains a large amount of thioether structure, It ensures the temperature characteristics of the enhancement agent under high temperature conditions and reduces the performance degradation caused by high temperature curling. Due to the thermosensitive calcium alginate film layer on the surface of the thermosensitive microspheres, the thermosensitive microspheres can penetrate into the oil layer. As the temperature rises, the thermosensitive calcium alginate film layer dissociates, thereby activating the petroleum hydrocarbon degrading bacteria loaded on the microspheres. The biosurfactants secreted by the petroleum hydrocarbon degrading bacteria can effectively fill the deficiencies of the enhancement agent and the polymer surfactant itself, effectively improving its dispersion stability, emulsification and oil displacement potential. At the same time, the microspheres themselves can play a certain plugging and displacement effect, thereby exerting a synergistic effect, further improving its oil displacement potential, and thus effectively 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 for oilfield production comprises the following steps: weighing the following raw materials in parts by weight: 15 parts of commercially available Sinobo S504 polymer surfactant, 8 parts of an enhancing agent, 6 parts of thermosensitive microspheres and 80 parts of water, mixing the polymer surfactant, the enhancing agent, the thermosensitive microspheres and the water to prepare a surfactant for oilfield production; The reinforcing aid is prepared by the following steps: Step A1: epichlorohydrin and potassium carbonate are mixed, stirred at a stirring rate of 120 rpm and a temperature of 70° C., lipoic acid is added, and the mixture is reacted for 24 hours to obtain a branched monomer; the branched monomer, tributylphosphine and anhydrous ethanol are mixed, stirred at a stirring rate of 150 rpm and a temperature of 70° C., the mixture is reacted for 24 hours, epichlorohydrin and sodium hydroxide solution are added, and the mixture is reacted for 6 hours to obtain a hyperbranched polymer; The amount ratio of epichlorohydrin, potassium carbonate and thioctic acid used in the preparation process of the branched monomer is 0.4 mol: 0.35 mol: 0.25 mol; the mass fraction of the sodium hydroxide solution used in the preparation process of the hyperbranched polymer is 10%, and the amount ratio of the branched monomer, tributylphosphine, epichlorohydrin and sodium hydroxide solution is 2.6 g: 5 g: 0.6 mol: 25 mL; Step A2: nicotinic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole and dichloromethane are mixed, stirred at a stirring rate of 240 rpm and room temperature, and octadecylamine is added to react for 12 hours to obtain an intermediate, and the intermediate, hyperbranched polymer and toluene are mixed, and reacted at a stirring rate of 150 rpm and a temperature of 110° C. for 24 hours to obtain a reinforcing agent; The ratio of nicotinic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole and octadecylamine is 0.1 mol: 5 g: 6 g: 0.1 mol, and the ratio of intermediate and hyperbranched polymer is 0.2 mol: 7 g; The temperature-sensitive microspheres are prepared by the following steps: Step B1: Tetramethoxysilane, deionized water and hydrochloric acid solution were mixed, stirred at a stirring rate of 80 rpm and room temperature for 1 hour, 3-aminopropyltrimethoxysilane was added, and stirring was continued for 1.5 hours, chitosan, deionized water and acetic acid solution were mixed and added, stirred at a stirring rate of 400 rpm and room temperature for 2 hours to obtain a water system, soybean oil and Span 80 were mixed, stirred at a stirring rate of 240 rpm and a temperature of 35°C, and the water system was added and stirred for 0.5 hours to obtain an emulsion system; The chitosan is commercially available Runtai 25kg*1 chitosan; The mass fraction of hydrochloric acid solution is 35%, the mass fraction of acetic acid solution is 2%, the dosage ratio of tetramethoxysilane, 3-aminopropyltrimethoxysilane, hydrochloric acid solution, chitosan and acetic acid solution is 0.5mL: 0.2mL: 0.02mL: 0.03g: 1mL; the dosage ratio of soybean oil, Span 80 and water system is 9mL: 0.1g: 1.2mL; Step B2: the emulsion system and the glutaraldehyde solution were mixed, and the mixture was reacted for 3 hours at a stirring rate of 80 rpm and a temperature of 45° C., and then the petroleum hydrocarbon degrading bacterial suspension was added and the reaction was continued for 4 hours to obtain loaded microspheres; The mass fraction of glutaraldehyde solution is 4%, the strain in the petroleum hydrocarbon degrading bacterial suspension is Bacillus cereus3096-3, the volume ratio of bacterial solution to culture medium is 5mL:95mL, the dosage ratio of petroleum hydrocarbon, sodium chloride, sodium dihydrogen phosphate, potassium dihydrogen phosphate, potassium chloride, magnesium sulfate, iron sulfate, manganese sulfate, zinc sulfate, copper sulfate, ammonium sulfate and deionized water in the culture medium is 10mL:28g:2g:2g:1g:1g:0.3g:0.3g:0.6g:0.7g:1g:1000mL, and the dosage ratio of emulsion system, glutaraldehyde solution and petroleum hydrocarbon degrading bacterial suspension is 10mL:30mL:8mL. Step B3: Cyclohexane, Span 80 and Tween 80 were mixed, stirred at a stirring rate of 240 rpm and a temperature of 30°C for 30 min, and then the loaded microspheres were added and stirred for 15 min to obtain an oil phase system, sodium alginate solution, calcium chloride and sodium hydroxide were mixed, stirred at a stirring rate of 120 rpm and room temperature for 30 min, and then added to the oil phase system, and reacted at a stirring rate of 80 rpm and a temperature of 60°C for 2 h to obtain thermosensitive microspheres; The sodium alginate used in the sodium alginate solution is commercially available 25kg*1 sodium alginate from Jiyesheng; The dosage ratio of cyclohexane, Span 80, Tween 80 and loaded microspheres is 75mL:5.5g:2.5g:0.6g; the mass fraction of sodium alginate solution is 1.5%, and the dosage ratio of sodium alginate solution, calcium chloride, sodium hydroxide and oil phase system is 35mL:1.2g:0.8g:65mL.

[0007] Example 2 A method for preparing a surfactant for oilfield production comprises the following steps: weighing the following raw materials in parts by weight: 20 parts of commercially available Sinobo S504 polymer surfactant, 8 parts of an enhancing agent, 8 parts of thermosensitive microspheres and 80 parts of water, mixing the polymer surfactant, the enhancing agent, the thermosensitive microspheres and the water to prepare a surfactant for oilfield production; The reinforcing aid is prepared by the following steps: Step A1: epichlorohydrin and potassium carbonate are mixed, stirred at a stirring rate of 150 rpm and a temperature of 70° C., thioctic acid is added, and the mixture is reacted for 24 hours to obtain a branched monomer; a branched monomer, tributylphosphine and anhydrous ethanol are mixed, stirred at a stirring rate of 150 rpm and a temperature of 70° C., the mixture is reacted for 24 hours, epichlorohydrin and a sodium hydroxide solution are added, and the mixture is reacted for 8 hours to obtain a hyperbranched polymer; The amount ratio of epichlorohydrin, potassium carbonate and thioctic acid used in the preparation process of the branched monomer is 0.4 mol: 0.4 mol: 0.25 mol; the mass fraction of the sodium hydroxide solution used in the preparation process of the hyperbranched polymer is 10%, and the amount ratio of the branched monomer, tributylphosphine, epichlorohydrin and sodium hydroxide solution is 2.6 g: 6 g: 0.7 mol: 25 mL; Step A2: nicotinic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole and dichloromethane are mixed, stirred at a stirring rate of 260 rpm and room temperature, and octadecylamine is added to react for 12 hours to obtain an intermediate, and the intermediate, hyperbranched polymer and toluene are mixed, stirred at a stirring rate of 180 rpm and a temperature of 110° C., and reacted for 24 hours to obtain a reinforcing agent; The ratio of nicotinic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole and octadecylamine is 0.1 mol: 5 g: 6 g: 0.12 mol, and the ratio of intermediate and hyperbranched polymer is 0.2 mol: 8 g; The temperature-sensitive microspheres are prepared by the following steps: Step B1: Tetramethoxysilane, deionized water and hydrochloric acid solution were mixed, stirred at a stirring rate of 80 rpm and room temperature for 1 hour, 3-aminopropyltrimethoxysilane was added, and stirring was continued for 2 hours, chitosan, deionized water and acetic acid solution were mixed and added, stirred at a stirring rate of 400 rpm and room temperature for 2 hours to obtain a water system, soybean oil and Span 80 were mixed, stirred at a stirring rate of 300 rpm and a temperature of 35°C, and the water system was added and stirred for 0.5 hours to obtain an emulsion system; The chitosan is commercially available Runtai 25kg*1 chitosan; The mass fraction of hydrochloric acid solution is 35%, the mass fraction of acetic acid solution is 2%, the dosage ratio of tetramethoxysilane, 3-aminopropyltrimethoxysilane, hydrochloric acid solution, chitosan and acetic acid solution is 0.5mL: 0.2mL: 0.02mL: 0.03g: 1.5mL; the dosage ratio of soybean oil, Span 80 and water system is 9mL: 0.1g: 1.4mL; Step B2: the emulsion system and the glutaraldehyde solution were mixed, and the mixture was reacted for 3 h at a stirring rate of 120 rpm and a temperature of 45° C., and then the petroleum hydrocarbon degradation bacterial suspension was added and the reaction was continued for 5 h to obtain loaded microspheres; The mass fraction of glutaraldehyde solution is 4%, the strain in the petroleum hydrocarbon degrading bacterial suspension is Bacillus cereus3096-3, the volume ratio of bacterial solution to culture medium is 5mL:95mL, the dosage ratio of petroleum hydrocarbon, sodium chloride, sodium dihydrogen phosphate, potassium dihydrogen phosphate, potassium chloride, magnesium sulfate, iron sulfate, manganese sulfate, zinc sulfate, copper sulfate, ammonium sulfate and deionized water in the culture medium is 10mL:28g:2g:2g:1g:1g:0.3g:0.3g:0.6g:0.7g:1g:1000mL, and the dosage ratio of emulsion system, glutaraldehyde solution and petroleum hydrocarbon degrading bacterial suspension is 10mL:35mL:8mL. Step B3: Cyclohexane, Span 80 and Tween 80 were mixed, stirred at a stirring rate of 260 rpm and a temperature of 30°C for 30 min, and then the loaded microspheres were added and stirred for 15 min to obtain an oil phase system, sodium alginate solution, calcium chloride and sodium hydroxide were mixed, stirred at a stirring rate of 120 rpm and room temperature for 30 min, and then added to the oil phase system, and reacted at a stirring rate of 100 rpm and a temperature of 60°C for 2 h to obtain thermosensitive microspheres; The sodium alginate used in the sodium alginate solution is commercially available 25kg*1 sodium alginate from Jiyesheng; The dosage ratio of cyclohexane, Span 80, Tween 80 and loaded microspheres is 75mL:6g:2.5g:0.7g; the mass fraction of sodium alginate solution is 1.5%, and the dosage ratio of sodium alginate solution, calcium chloride, sodium hydroxide and oil phase system is 35mL:1.5g:0.8g:70mL.

[0008] Example 3 A method for preparing a surfactant for oilfield production comprises the following steps: weighing the following raw materials in parts by weight: 20 parts of commercially available Sinobo S504 polymer surfactant, 12 parts of an enhancing agent, 8 parts of thermosensitive microspheres and 90 parts of water, mixing the polymer surfactant, the enhancing agent, the thermosensitive microspheres and the water to prepare a surfactant for oilfield production; The reinforcing aid is prepared by the following steps: Step A1: epichlorohydrin and potassium carbonate are mixed, stirred at a stirring rate of 150 rpm and a temperature of 70° C., thioctic acid is added, and the mixture is reacted for 24 hours to obtain a branched monomer; the branched monomer, tributylphosphine and anhydrous ethanol are mixed, stirred at a stirring rate of 180 rpm and a temperature of 70° C., the mixture is reacted for 24 hours, epichlorohydrin and sodium hydroxide solution are added, and the mixture is reacted for 8 hours to obtain a hyperbranched polymer; The amount ratio of epichlorohydrin, potassium carbonate and thioctic acid used in the preparation process of the branched monomer is 0.5 mol: 0.4 mol: 0.3 mol; the mass fraction of the sodium hydroxide solution used in the preparation process of the hyperbranched polymer is 10%, and the amount ratio of the branched monomer, tributylphosphine, epichlorohydrin and sodium hydroxide solution is 3 g: 6 g: 0.7 mol: 30 mL; Step A2: nicotinic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole and dichloromethane are mixed, stirred at a stirring rate of 260 rpm and room temperature, and octadecylamine is added to react for 14 hours to obtain an intermediate, and the intermediate, hyperbranched polymer and toluene are mixed, and reacted at a stirring rate of 180 rpm and a temperature of 110° C. for 24 hours to obtain a reinforcing agent; The ratio of nicotinic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole and octadecylamine is 0.12 mol: 5 g: 6 g: 0.12 mol, and the ratio of intermediate and hyperbranched polymer is 0.3 mol: 8 g; The temperature-sensitive microspheres are prepared by the following steps: Step B1: Tetramethoxysilane, deionized water and hydrochloric acid solution were mixed, stirred at a stirring rate of 120 rpm and room temperature for 1 hour, 3-aminopropyltrimethoxysilane was added, and stirring was continued for 2 hours, chitosan, deionized water and acetic acid solution were mixed and added, stirred at a stirring rate of 500 rpm and room temperature for 2 hours to obtain a water system, soybean oil and Span 80 were mixed, stirred at a stirring rate of 300 rpm and a temperature of 35°C, and the water system was added and stirred for 0.5 hours to obtain an emulsion system; The chitosan is commercially available Runtai 25kg*1 chitosan; The mass fraction of hydrochloric acid solution is 35%, the mass fraction of acetic acid solution is 2%, the dosage ratio of tetramethoxysilane, 3-aminopropyltrimethoxysilane, hydrochloric acid solution, chitosan and acetic acid solution is 0.8mL: 0.3mL: 0.03mL: 0.04g: 1.5mL; the dosage ratio of soybean oil, Span 80 and water system is 11mL: 0.2g: 1.4mL; Step B2: the emulsion system and the glutaraldehyde solution were mixed, and the mixture was reacted for 4 hours at a stirring rate of 120 rpm and a temperature of 45° C., and then the petroleum hydrocarbon degradation bacterial suspension was added and the reaction was continued for 5 hours to obtain loaded microspheres; The mass fraction of glutaraldehyde solution is 4%, the strain in the petroleum hydrocarbon degrading bacterial suspension is Bacillus cereus3096-3, the volume ratio of bacterial solution to culture medium is 5mL:95mL, the dosage ratio of petroleum hydrocarbon, sodium chloride, sodium dihydrogen phosphate, potassium dihydrogen phosphate, potassium chloride, magnesium sulfate, iron sulfate, manganese sulfate, zinc sulfate, copper sulfate, ammonium sulfate and deionized water in the culture medium is 10mL:28g:2g:2g:1g:1g:0.3g:0.3g:0.6g:0.7g:1g:1000mL, and the dosage ratio of emulsion system, glutaraldehyde solution and petroleum hydrocarbon degrading bacterial suspension is 11.5mL:335mL:10mL; Step B3: Cyclohexane, Span 80 and Tween 80 were mixed, stirred at a stirring rate of 260 rpm and a temperature of 30°C for 30 min, and then the loaded microspheres were added and stirred for 15 min to obtain an oil phase system, sodium alginate solution, calcium chloride and sodium hydroxide were mixed, stirred at a stirring rate of 140 rpm and room temperature for 30 min, and then added to the oil phase system, and reacted at a stirring rate of 100 rpm and a temperature of 60°C for 2 h to obtain thermosensitive microspheres; The sodium alginate used in the sodium alginate solution is commercially available 25kg*1 sodium alginate from Jiyesheng; The dosage ratio of cyclohexane, Span 80, Tween 80 and loaded microspheres is 85mL:6g:3g:0.7g; the mass fraction of sodium alginate solution is 1.5%, and the dosage ratio of sodium alginate solution, calcium chloride, sodium hydroxide and oil phase system is 40mL:1.5g:1.2g:70mL.

[0009] Comparative Example 1 Compared with Example 3, this comparative example is different in that the petroleum hydrocarbon-degrading bacterial suspension in the preparation process of the thermosensitive microspheres in Example 3 is replaced with deionized water, and the other steps are the same.

[0010] Comparative Example 2 Compared with Example 3, this comparative example replaces the temperature-sensitive microspheres used in the preparation of the surfactant for oil field production in Example 3 with the loaded microspheres in Example 3.

[0011] Comparative Example 3 Compared with Example 3, this comparative example is different from Example 3 in that the hyperbranched polymer in the preparation process of the reinforcing auxiliary agent in Example 3 is replaced by commercially available MeloPEG chlorinated polyethylene glycol.

[0012] Take the surfactant for oilfield production prepared in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2 and Comparative Example 3, mix 110g of the surfactant for oilfield production, 80mL of nutrient solution and 1000mL of deionized water, and stir for 12h at a temperature of 50°C to prepare an oil displacement system. Referring to SY / T 5153-2007, core flooding experiments were carried out at temperatures of 50°C and 75°C, using permeabilities of 50×10 -3μm 2 ,300×10 -3 μm 2 and 800×10 -3 μm 2 The core gradient combination is formed into a heterogeneous artificial core. The water flooding and polymer flooding methods are first used for testing and the recovery rate is calculated. Then the oil flooding system is used for the third oil flooding and the third oil flooding recovery rate is calculated. The test results are shown in Table 1: Table 1 Test results Test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 50℃ oil recovery rate (%) 23.79 24.27 24.57 23.61 31.46 22.19 75℃ oil recovery rate (%) 44.80 45.53 45.73 27.36 36.84 40.02 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, the petroleum hydrocarbon degrading bacteria suspension in the preparation process of the thermosensitive microspheres in Example 3 is replaced with deionized water. Due to the lack of petroleum hydrocarbon degrading bacteria, its recovery rate decreases under high temperature conditions. Comparative Example 2 replaces the thermosensitive microspheres in the preparation process of the surfactant for oil field production in Example 3 with the loaded microspheres in Example 3. Due to the lack of the thermosensitive layer, it is unable to play the role of plugging and driving synergistically and penetrating into the oil layer, resulting in a decrease in its recovery rate. Comparative Example 3 replaces the hyperbranched polymer in the preparation process of the enhancing auxiliary agent in Example 3 with terminal chlorinated polyethylene glycol. Due to the lack of thioether structure and hyperbranched structure, its high temperature performance is reduced and the recovery rate is 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, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a surfactant for oil field production, characterized in that: The method comprises the following steps: weighing the following raw materials in parts by weight: 15-20 parts of a polymer surfactant, 8-12 parts of an enhancing agent, 6-8 parts of a thermosensitive microsphere and 80-90 parts of water, and mixing the polymer surfactant, the enhancing agent, the thermosensitive microsphere and the water to prepare a surfactant for oil field production; The polymer surfactant is Sinobao S504 polymer surfactant; The reinforcing agent is prepared by the following steps: Step A1: epichlorohydrin and potassium carbonate are mixed, stirred at a stirring rate of 120-150 rpm and a temperature of 70° C., thioctic acid is added, and the mixture is reacted for 24 hours to obtain a branched monomer; the branched monomer, tributylphosphine and anhydrous ethanol are mixed, stirred at a stirring rate of 150-180 rpm and a temperature of 70° C., the mixture is reacted for 24 hours, epichlorohydrin and sodium hydroxide solution are added, and the mixture is reacted for 6-8 hours to obtain a hyperbranched polymer; Step A2: nicotinic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole and dichloromethane are mixed, stirred at a stirring rate of 240-260 rpm and room temperature, and octadecylamine is added, and the mixture is reacted for 12-14 hours to obtain an intermediate, and the intermediate, a hyperbranched polymer and toluene are mixed, and the mixture is reacted for 24 hours at a stirring rate of 150-180 rpm and a temperature of 110° C. to obtain a reinforcing agent; The temperature-sensitive microspheres are prepared by the following steps: Step B1: Tetramethoxysilane, deionized water and hydrochloric acid solution are mixed, stirred at a stirring rate of 80-120 rpm and room temperature for 1 hour, 3-aminopropyltrimethoxysilane is added, and stirring is continued for 1.5-2 hours, chitosan, deionized water and acetic acid solution are mixed and added, stirred at a stirring rate of 400-500 rpm and room temperature for 2 hours to obtain a water system, soybean oil and Span 80 are mixed, stirred at a stirring rate of 240-300 rpm and a temperature of 35°C, and the water system is added and stirred for 0.5 hours to obtain an emulsion system; Step B2: the emulsion system and the glutaraldehyde solution are mixed, and the reaction is carried out for 3-4 hours at a stirring rate of 80-120 rpm and a temperature of 45° C., and then the petroleum hydrocarbon degradation bacterial suspension is added and the reaction is continued for 4-5 hours to obtain loaded microspheres; Step B3: Mix cyclohexane, Span 80 and Tween 80, stir for 30 minutes at a stirring rate of 240-260rpm and a temperature of 30°C, then add the loaded microspheres and stir for 15 minutes to obtain an oil phase system, mix the sodium alginate solution, calcium chloride and sodium hydroxide, stir for 30 minutes at a stirring rate of 120-140rpm and room temperature, then add them to the oil phase system, react for 2 hours at a stirring rate of 80-100rpm and a temperature of 60°C to obtain thermosensitive microspheres.

2. The method for preparing a surfactant for oil field production according to claim 1, characterized in that: In step A1: the amount ratio of epichlorohydrin, potassium carbonate and thioctic acid used in the preparation process of the branched monomer is 0.4-0.5 mol: 0.35-0.4 mol: 0.25-0.3 mol; the mass fraction of the sodium hydroxide solution used in the preparation process of the hyperbranched polymer is 10%, and the amount ratio of the branched monomer, tributylphosphine, epichlorohydrin and sodium hydroxide solution is 2.6-3g: 5-6g: 0.6-0.7mol: 25-30mL.

3. The method for preparing a surfactant for oil field production according to claim 1, characterized in that: In step A2, the ratio of nicotinic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole and octadecylamine is 0.1-0.12 mol: 5 g: 6 g: 0.1-0.12 mol, and the ratio of the intermediate and the hyperbranched polymer is 0.2-0.3 mol: 7-8 g.

4. The method for preparing a surfactant for oil field production according to claim 1, characterized in that: In step B1: the mass fraction of hydrochloric acid solution is 35%, the mass fraction of acetic acid solution is 2%, the amount ratio of tetramethoxysilane, 3-aminopropyltrimethoxysilane, hydrochloric acid solution, chitosan and acetic acid solution is 0.5-0.8mL: 0.2-0.3mL: 0.02-0.03mL: 0.03-0.04g: 1-1.5mL; the amount ratio of soybean oil, Span 80 and water system is 9-11mL: 0.1-0.2g: 1.2-1.4mL.

5. The method for preparing a surfactant for oil field production according to claim 1, characterized in that: In step B2: the mass fraction of the glutaraldehyde solution is 4%, the strain in the petroleum hydrocarbon degrading bacterial suspension is Bacillus cereus 3096-3, the volume ratio of the bacterial solution to the culture medium is 5mL:95mL, the amount ratio of petroleum hydrocarbon, sodium chloride, sodium dihydrogen phosphate, potassium dihydrogen phosphate, potassium chloride, magnesium sulfate, iron sulfate, manganese sulfate, zinc sulfate, copper sulfate, ammonium sulfate and deionized water in the culture medium is 10mL:28g:2g:2g:1g:1g:0.3g:0.3g:0.6g:0.7g:1g:1000mL, and the amount ratio of the emulsion system, the glutaraldehyde solution and the petroleum hydrocarbon degrading bacterial suspension is 10-11.5mL:30-35mL:8-10mL.

6. The method for preparing a surfactant for oil field production according to claim 1, characterized in that: In step B3: the dosage ratio of cyclohexane, Span 80, Tween 80 and loaded microspheres is 75-85 mL: 5.5-6g:2.5-3g:0.6-0.7g; the mass fraction of sodium alginate solution is 1.5%, and the dosage ratio of sodium alginate solution, calcium chloride, sodium hydroxide and oil phase system is 35-40mL:1.2-1.5g:0.8-1.2g:65-70mL.

7. A surfactant for oil field production, characterized in that: Prepared according to any one of claims 1 to 6.