A nano-permeation oil displacement and unblocking agent and its preparation method

Abstract

This invention relates to a nano-permeable oil displacement and unblocking agent and its preparation method, belonging to the field of unblocking agent technology. It comprises the following raw materials: 8-12 parts of modified surfactant, 4-6 parts of polycarboxylic acid ammonium salt, 2-4 parts of metal chelating agent, 1-2 parts of nitrogen-containing compound, 1.5-2.5 parts of bactericide, 2-3 parts of dispersant, and 60-70 parts of deionized water. In this invention, a composite material is obtained by combining anhydride compounds with natural plant gums; the composite material is then combined with a silanized reinforcing material to obtain a modified surfactant; the modified surfactant, polycarboxylic acid ammonium salt, metal chelating agent, nitrogen-containing compound, bactericide, dispersant, and deionized water are mixed and stirred evenly to finally obtain the nano-permeable oil displacement and unblocking agent. The modified surfactant effectively improves the oil displacement performance, permeation capacity, stability, and unblocking performance of the nano-permeable oil displacement and unblocking agent, and also exhibits good corrosion resistance and environmental friendliness, demonstrating excellent overall performance.

Description

Technical Field

[0001] This invention belongs to the field of unblocking agent technology, specifically, it relates to a nano-permeation oil displacement unblocking agent and its preparation method. Background Technology

[0002] With the increasing depletion of oil resources, the efficient development of low-permeability reservoirs has become a key focus for increasing oilfield production. However, low-permeability reservoirs are generally characterized by low porosity, small throat radius, poor matrix permeability, and high clay mineral content, leading to low water injection efficiency and difficulty in crude oil extraction. Furthermore, during long-term water injection, calcium and magnesium ions carried in the produced water easily form carbonate or sulfate precipitates, further clogging oil reservoir channels and causing a decline in well productivity. To improve the oil displacement efficiency of low-permeability reservoirs, oilfields currently commonly use chemical unblocking agents to improve seepage conditions. Most existing unblocking agents are based on acidic or strong oxidizing systems. While they can alleviate inorganic scale blockage to some extent, they still have many shortcomings, such as significant disturbance to the reservoir pH environment, strong corrosiveness, poor stability, and safety hazards. In addition, these traditional unblocking agents are poorly adapted to complex situations such as polymer blockage and biological bacterial blockage, making it difficult to meet the diverse and complex unblocking needs of modern oilfields. Therefore, there is an urgent need to develop a stable and widely applicable nano-permeability oil displacement unblocking agent. This unblocking agent can effectively reduce the oil-water interfacial tension, improve rock wettability, and efficiently disperse and remove blockages in micropores without changing the reservoir pH, thereby significantly improving the permeability and oil recovery rate of low-permeability reservoirs.

[0003] In existing technologies, nano-permeation oil displacement and unblocking agents typically enhance oil displacement by adding polymers (such as polyacrylamide). However, these polymers are prone to hydrolysis at high temperatures, leading to a significant decrease in their stability and salt resistance, thus limiting their widespread application. Furthermore, traditional nano-permeation oil displacement and unblocking agents improve unblocking performance by adding nanoparticles. However, due to the high surface energy of nanoparticles, they are prone to aggregation in solution, resulting in a significant reduction in the permeability and oil displacement effect of the unblocking agent. In addition, aggregated nanoparticles may clog micropores, exacerbating reservoir damage and thus affecting the overall oil recovery rate. Moreover, most unblocking agents contain strong acids, strong oxidants, and other chemical components, which are environmentally unfriendly and can cause harm to the environment and human health during use. Summary of the Invention

[0004] The purpose of this invention is to provide a nano-permeable oil displacement and unblocking agent and its preparation method. The method involves combining anhydride compounds with natural plant gums to obtain a composite material; combining the composite material with a silanized reinforcing material to obtain a modified surfactant; and mixing the modified surfactant, polycarboxylic acid ammonium salt, metal chelating agent, nitrogen-containing compound, bactericide, dispersant, and deionized water, and stirring until homogeneous to obtain the nano-permeable oil displacement and unblocking agent. The modified surfactant effectively improves the unblocking performance, stability, oil displacement effect, and permeation capacity of the unblocking agent, while also enhancing its corrosion resistance and environmental friendliness, expanding its application range, and overall improving the comprehensive performance of the unblocking agent.

[0005] The technical problem this invention aims to solve is as follows: In the prior art, nano-permeation oil displacement and unblocking agents typically enhance the oil displacement effect by adding polymers (such as polyacrylamide). However, these polymers are prone to hydrolysis under high-temperature conditions, leading to a significant decrease in their stability and salt resistance, which limits their widespread application. Furthermore, traditional nano-permeation oil displacement and unblocking agents improve unblocking performance by adding nanoparticles. However, due to the high surface energy of nanoparticles, they are prone to aggregation in solution, resulting in a significant reduction in the permeability and oil displacement effect of the unblocking agent. In addition, aggregated nanoparticles may clog micropores, exacerbating reservoir damage and thus affecting the overall oil recovery rate. Moreover, most unblocking agents contain strong acids, strong oxidants, and other chemical components, which are environmentally unfriendly and can cause harm to the environment and human health during use.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A nano-permeation oil displacement and unblocking agent comprises the following raw materials in parts by weight: 8-12 parts modified surfactant, 4-6 parts polycarboxylic acid ammonium salt, 2-4 parts metal chelating agent, 1-2 parts nitrogen-containing compound, 1.5-2.5 parts bactericide, 2-3 parts dispersant, and 60-70 parts deionized water;

[0008] The preparation method of modified surfactants includes the following steps:

[0009] S1: A composite material is obtained by combining acid anhydride compounds with natural plant gums;

[0010] S2: Combine the composite material from step S1 with the silanized reinforcing material to obtain the modified surfactant.

[0011] Furthermore, step S1 specifically includes:

[0012] Natural plant gum was added to deionized water, followed by sodium bicarbonate, and stirred for 1-1.5 hours. Then, an acid anhydride compound was added and stirred to react. After the reaction was completed, the mixture was added to anhydrous ethanol to precipitate the product. The product was then washed with anhydrous ethanol, dialyzed with deionized water, and finally freeze-dried to obtain the composite material.

[0013] In the above reaction process, natural plant gums contain hydroxyl groups, and acid anhydride compounds contain acid anhydride groups. The hydroxyl groups in natural plant gums can combine with the acid anhydride groups in acid anhydride compounds, thus combining natural plant gums and acid anhydride compounds to finally obtain composite materials.

[0014] Furthermore, the mass ratio of the natural plant gum, deionized water, sodium bicarbonate, and acid anhydride compounds is 0.02-0.04: 20-40: 1.4-1.6: 0.02-0.04.

[0015] Furthermore, the natural plant gum is composed of guar gum and vetiver gum mixed in a mass ratio of 1-1.2:0.7-0.9.

[0016] Furthermore, the anhydride compound is composed of a mixture of 2-octenylsuccinic anhydride and dodecenylsuccinic anhydride in a mass ratio of 0.8-0.9:0.5-0.6.

[0017] Furthermore, the temperature of the stirring reaction is 35-45℃, and the time is 5.5-6.5h.

[0018] Furthermore, the freeze-drying temperature is -50 to -40°C.

[0019] Furthermore, step S2 specifically includes:

[0020] The silanized reinforcing material was added to deionized water and stirred for 25-35 minutes. The composite material from step S1 was then added under a nitrogen atmosphere and stirred. The catalyst and sodium bisulfite were then added and a polymerization reaction was carried out. After the reaction was completed, the mixture was cooled to room temperature, washed with ethanol and deionized water, and finally dried under vacuum to obtain the modified surfactant.

[0021] In the above reaction process, the silanized reinforcing material has carbon-carbon double bonds, and the composite material also has carbon-carbon double bonds. The carbon-carbon double bonds on the silanized reinforcing material can undergo a polymerization reaction with the carbon-carbon double bonds in the composite material under the action of a catalyst, thereby combining the composite material with the silanized reinforcing material, and finally obtaining the modified surfactant.

[0022] Furthermore, the mass ratio of the silanized reinforcing material, deionized water, composite material, catalyst, and sodium bisulfite is 0.3-0.5: 35-45: 5.9-6.1: 0.1-0.15: 0.06-0.08.

[0023] Furthermore, the catalyst is ammonium persulfate.

[0024] Furthermore, the stirring temperature is 35-45℃ and the stirring time is 25-35 minutes.

[0025] Furthermore, the polymerization reaction is carried out at a temperature of 35-45°C for a time of 3.5-4.5 hours.

[0026] Furthermore, the vacuum drying temperature is 30-40°C.

[0027] Furthermore, the preparation method of the silanized reinforced material includes the following steps:

[0028] The reinforcing material is added to deionized water and stirred for 25-35 minutes. Then, it is ultrasonically treated, followed by the addition of a silane coupling agent. The mixture is then placed in a constant temperature water bath for reaction. After the reaction is complete, the mixture is washed with ethanol and deionized water and finally dried under vacuum to obtain the silanized reinforcing material.

[0029] During the above reaction process, the surface of the reinforcing material has hydroxyl groups. After the silane coupling agent is hydrolyzed, silanol groups are generated. The silanol groups in the silane coupling agent can combine with the hydroxyl groups on the reinforcing material, grafting the silane coupling agent onto the surface of the reinforcing material, and finally obtaining the silanized reinforcing material.

[0030] Furthermore, the mass ratio of the reinforcing material, deionized water, and silane coupling agent is 0.9-1.1:50-60:0.2-0.4.

[0031] Furthermore, the silane coupling agent is composed of 3-(methacryloyloxy)propyltrimethoxysilane and vinyltriethoxysilane mixed in a mass ratio of 2:1.

[0032] Furthermore, the ultrasonic treatment time is 1.5-2.5 hours.

[0033] Furthermore, the reaction temperature of the constant temperature water bath is 75-85℃, and the reaction time is 5.5-6.5h.

[0034] Furthermore, the vacuum drying temperature is 60-70°C.

[0035] Furthermore, the method for preparing the reinforcing material includes the following steps:

[0036] Carboxylated graphene oxide and deionized water were mixed evenly and subjected to ultrasonic treatment. Then, nanoparticles and hexadecyltrimethylammonium bromide were added and stirred to react. After the reaction was completed, the mixture was centrifuged, washed with ethanol and deionized water, and finally freeze-dried to obtain the reinforced material.

[0037] In the above reaction process, hexadecyltrimethylammonium bromide can be adsorbed on the surface of nanoparticles, giving them a positive charge in aqueous solution. Carboxylated graphene oxide has a negative charge in aqueous solution. The positive charge on the surface of the nanoparticles can combine with the negative charge on the surface of the carboxylated graphene oxide through electrostatic self-assembly, thereby uniformly coating the nanoparticles on the surface of the carboxylated graphene oxide, and finally obtaining the reinforcing material.

[0038] Furthermore, the mass ratio of the carboxylated graphene oxide, deionized water, nanoparticles, and hexadecyltrimethylammonium bromide is 0.08-0.12:90-110:0.2-0.3:0.6-0.7.

[0039] Furthermore, the nanoparticles are composed of nano-silica, nano-alumina and nano-titanium dioxide in a mass ratio of 0.9-1.1:0.7-0.8:0.4-0.5.

[0040] Furthermore, the ultrasonic treatment time is 30-40 minutes.

[0041] Furthermore, the temperature of the stirring reaction is 20-30℃, and the time is 22-24h.

[0042] A method for preparing a nano-absorption oil displacement and unblocking agent includes the following steps:

[0043] Weigh out the raw materials by mass, mix the modified surfactant, polycarboxylic acid ammonium salt, metal chelating agent, nitrogen-containing compound, bactericide, dispersant and deionized water evenly, and then stir at 30-40℃ to finally obtain the nano-permeation oil displacement and unblocking agent.

[0044] Furthermore, the polycarboxylic acid ammonium salt is composed of diammonium hydrogen citrate and ammonium gluconate mixed in a mass ratio of 1:1.

[0045] Furthermore, the metal chelating agent is composed of hydroxyethylidene diphosphonic acid and polyepoxysuccinic acid mixed in a mass ratio of 0.7-0.8:0.5-0.6.

[0046] Furthermore, the nitrogen-containing compound is at least one of benzotriazole, benzimidazole, triethanolamine, and diethylenetriamine.

[0047] Furthermore, the bactericide is composed of calcium hypochlorite, dodecyl dimethyl benzyl ammonium chloride, and tea polyphenols in a mass ratio of 0.6-0.7:0.4-0.5:1.

[0048] Further, the dispersant is at least one of sodium dodecylbenzenesulfonate, polyethylene glycol fatty acid ester, octadecyl betaine, and sodium polyacrylate.

[0049] Furthermore, the stirring time is 2-4 hours.

[0050] A nano-permeation oil displacement and unblocking agent is prepared by the above-mentioned preparation method of nano-permeation oil displacement and unblocking agent.

[0051] The beneficial effects of this invention are:

[0052] (1) In the technical solution of this invention, a composite material is obtained by combining anhydride compounds with natural plant gums; wherein, the natural plant gums are composed of a mixture of vesicar gum and guar gum, which have a synergistic effect. Both vesicar gum and guar gum have good thickening effects and can improve the fluidity of the solution, further improving the stability of the unblocking agent and enhancing its oil displacement effect and permeation capacity; the anhydride compounds are composed of a mixture of 2-octenyl succinic anhydride and dodecenyl succinic anhydride, which also have a good synergistic effect, helping to significantly reduce the oil-water interfacial tension, which is beneficial for crude oil to flow from the rock. The oil is more effectively displaced from the pores of the rock, which improves the oil displacement effect of the unblocking agent and increases its self-adsorption recovery rate and stability. The combination of acid anhydride compounds and natural plant gums has good binding force and can form an amphiphilic surfactant, which can significantly reduce the oil-water interfacial tension, help improve rock wettability, enhance the stability and salt resistance of the unblocking agent, effectively improve the oil displacement effect and adsorption capacity of the unblocking agent, and has good environmental protection. At the same time, it can also provide reaction sites for subsequent reactions, further enhancing the overall performance of the unblocking agent.

[0053] (2) In the technical solution of the present invention, the composite material is combined with the silanized reinforcing material to obtain the modified surfactant; the silanized reinforcing material is obtained by grafting the reinforcing material with a silane coupling agent; the silane coupling agent can not only improve the dispersibility of the reinforcing material and prevent its agglomeration, but also increase the bonding force between the composite material and the reinforcing material; the reinforcing material is obtained by combining carboxylated graphene oxide and nanoparticles; the nanoparticles are uniformly coated on the surface of carboxylated graphene oxide, which can further increase the dispersibility of the nanoparticles, prevent their agglomeration, and effectively enhance the unblocking performance and stability of the unblocking agent, further improving the oil displacement effect and permeation energy of the unblocking agent. The nanoparticles are composed of a mixture of nano-silica, nano-alumina, and nano-titanium dioxide. These three components work synergistically to improve the wettability of rock surfaces, reduce oil-water interfacial tension, enhance the stability and salt resistance of the unblocking agent, and further improve its permeation capacity, oil displacement effect, and unblocking performance. Simultaneously, they enhance its corrosion resistance and environmental friendliness. A nano-permeation oil displacement and unblocking agent is obtained by mixing modified surfactants, polycarboxylic acid ammonium salts, metal chelating agents, nitrogen-containing compounds, bactericides, dispersants, and deionized water, and stirring until homogeneous. The modified surfactants significantly improve the overall performance of the nano-permeation oil displacement and unblocking agent.

[0054] (3) In the technical solution of the present invention, after combining acid anhydride compounds with natural plant gums, and then combining them with silanized reinforcing materials, a modified surfactant is obtained. The modified surfactant, polycarboxylic acid ammonium salt, metal chelating agent, nitrogen-containing compound, bactericide, dispersant and deionized water are mixed and stirred evenly to finally obtain a nano-permeation oil displacement unblocking agent. It can not only improve the unblocking performance, oil displacement effect, stability and permeation capacity of the unblocking agent, but also the nano-permeation oil displacement unblocking agent has good corrosion resistance and environmental protection, expands its application range and has good overall performance. Detailed Implementation

[0055] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0056] The specific parameters of the raw materials used in this invention are as follows:

[0057] 2-Octenylsuccinic anhydride, CAS No.: 42482-06-4, Product No.: BD00823234, provided by Shanghai Bide Pharmaceutical Technology Co., Ltd.; Dodecenylsuccinic anhydride, CAS No.: 26544-38-7, Product No.: BD02147955, provided by Shanghai Bide Pharmaceutical Technology Co., Ltd.; Vilan gum, provided by Zhengzhou Jiuting Chemical Products Co., Ltd.; Guar gum, provided by Henan Jiqian Biotechnology Co., Ltd.; Carboxylated graphene oxide, Product No.: BK2020062233-01, provided by Suzhou Kaifa New Material Technology Co., Ltd.; Nano silica, CAS No.: 7631-86 -9, Product No.: A61745, provided by Saen Chemical Technology (Shanghai) Co., Ltd.; Nano alumina, Model: CY-L30, Particle Size: 30nm, provided by Hangzhou Jiupeng New Materials Co., Ltd.; Nano titanium dioxide (anatase nano titanium dioxide), Model: VK-TA18, Particle Size: 20nm, provided by Xuancheng Jingrui New Materials Co., Ltd.; Polyepoxysuccinic acid, CAS No.: 51274-37-4, provided by Jiangsu Puleisi Biotechnology Co., Ltd.; Sodium polyacrylate, CAS No.: 9003-04-7, Product No.: P434406, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0058] Example 1

[0059] The specific steps for preparing the modified surfactant are as follows:

[0060] S1: Following a mass ratio of 0.02:20:1.4:0.02 for natural plant gum, deionized water, sodium bicarbonate, and acid anhydride compounds, the natural plant gum was added to deionized water, followed by sodium bicarbonate, and stirred for 1 hour. Then, the acid anhydride compounds were added, and the mixture was stirred at 35°C for 6.5 hours. After the reaction, the mixture was added to anhydrous ethanol (the mass of anhydrous ethanol was equal to the mass of deionized water) to precipitate. The precipitate was then washed three times with anhydrous ethanol (each time the mass of anhydrous ethanol was 50% of the mass of deionized water), transferred to a dialysis bag (molecular weight cutoff 14 kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at -50°C for 24 hours to obtain the composite material. The natural plant gum was composed of a mixture of guar gum and vetiver gum in a mass ratio of 1:0.7; the acid anhydride compounds were composed of a mixture of 2-octenyl succinic anhydride and dodecenyl succinic anhydride in a mass ratio of 0.8:0.5.

[0061] S2: According to the mass ratio of silanized reinforcing material, deionized water, composite material, ammonium persulfate, and sodium bisulfite of 0.3:35:5.9:0.1:0.06, the silanized reinforcing material was added to deionized water and stirred at 10,000 rpm for 35 min. The composite material from step S1 was added under a nitrogen atmosphere, and then heated to 35°C and stirred for 35 min. Ammonium persulfate and sodium bisulfite were then added, and the polymerization reaction was carried out at 35°C for 4.5 h. After the reaction was completed, the mixture was cooled to room temperature and washed three times each with ethanol and deionized water (each time the mass of ethanol was 40% of the mass of deionized water, and each time the mass of deionized water was 50% of the mass of the above deionized water). Finally, the mixture was vacuum dried at 30°C for 24 h to obtain the modified surfactant.

[0062] The preparation method of silanized reinforced materials includes the following steps:

[0063] The reinforcing material, deionized water, and silane coupling agent were mixed in a mass ratio of 0.9:50:0.2. The reinforcing material was added to the deionized water and stirred for 25 min. Then, it was ultrasonically treated for 1.5 h (ultrasonic power of 100 W and ultrasonic frequency of 40 kHz). The silane coupling agent was then added and the mixture was placed in a constant temperature water bath at 75 °C for 6.5 h. After the reaction, the mixture was washed three times each with ethanol and deionized water (each time the mass of ethanol was 20% of the mass of deionized water, and each time the mass of deionized water was 30% of the mass of the deionized water). Finally, the mixture was vacuum dried at 60 °C for 12 h to obtain the silanized reinforcing material. The silane coupling agent was composed of 3-(methacryloyloxy)propyltrimethoxysilane and vinyltriethoxysilane mixed in a mass ratio of 2:1.

[0064] The preparation method of the reinforcing material includes the following steps:

[0065] Carboxylated graphene oxide, deionized water, nanoparticles, and hexadecyltrimethylammonium bromide were mixed uniformly according to a mass ratio of 0.08:90:0.2:0.6. The mixture was then ultrasonically treated for 30 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Nanoparticles and hexadecyltrimethylammonium bromide were then added, and the mixture was stirred at 20 °C for 24 h. After the reaction, the mixture was centrifuged at 8000 rpm for 15 min and washed three times each with ethanol and deionized water (each time the ethanol mass was 10% of the deionized water mass, and each time the deionized water mass was 15% of the deionized water mass). Finally, the mixture was freeze-dried at -50 °C for 24 h to obtain the reinforcing material. The nanoparticles were composed of nano-silica, nano-alumina, and nano-titanium dioxide in a mass ratio of 0.9:0.7:0.4.

[0066] A nano-permeation oil displacement and unblocking agent comprises the following raw materials in parts by weight: 8 parts modified surfactant, 4 parts polycarboxylic acid ammonium salt, 2 parts metal chelating agent, 1 part benzotriazole, 1.5 parts bactericide, 2 parts sodium dodecylbenzenesulfonate, and 60 parts deionized water.

[0067] Among them, the polycarboxylic acid ammonium salt is composed of diammonium hydrogen citrate and ammonium gluconate in a mass ratio of 1:1; the metal chelating agent is composed of hydroxyethylidene diphosphonic acid and polyepoxysuccinic acid in a mass ratio of 0.7:0.5; and the bactericide is composed of calcium hypochlorite, dodecyl dimethyl benzyl ammonium chloride and tea polyphenols in a mass ratio of 0.6:0.4:1.

[0068] The preparation method includes the following steps:

[0069] Weigh out the raw materials by mass, mix the modified surfactant, polycarboxylic acid ammonium salt, metal chelating agent, benzotriazole, bactericide, sodium dodecylbenzenesulfonate and deionized water evenly, and then stir at 30℃ for 4 hours to finally obtain the nano-permeation oil displacement and unblocking agent.

[0070] Example 2

[0071] The specific steps for preparing the modified surfactant are as follows:

[0072] S1: The natural plant gum, deionized water, sodium bicarbonate, and acid anhydride compounds were mixed in a mass ratio of 0.03:30:1.5:0.03. The natural plant gum was added to deionized water, followed by sodium bicarbonate, and stirred for 1.2 hours. Then, the acid anhydride compounds were added, and the mixture was stirred at 40°C for 6 hours. After the reaction, the mixture was added to anhydrous ethanol (the mass of anhydrous ethanol was equal to the mass of deionized water) to precipitate the product. The product was then washed three times with anhydrous ethanol (each time the mass of anhydrous ethanol was 50% of the mass of deionized water), transferred to a dialysis bag (molecular weight cutoff 14 kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at -45°C for 24 hours to obtain the composite material. The natural plant gum was composed of a mixture of guar gum and vetiver in a mass ratio of 1.1:0.8; the acid anhydride compounds were composed of a mixture of 2-octenyl succinic anhydride and dodecenyl succinic anhydride in a mass ratio of 0.85:0.55.

[0073] S2: According to the mass ratio of silanized reinforcing material, deionized water, composite material, ammonium persulfate, and sodium bisulfite of 0.4:40:6:0.12:0.07, the silanized reinforcing material was added to the deionized water and stirred at 12000 rpm for 30 min. The composite material from step S1 was added under a nitrogen atmosphere, and then heated to 40°C and stirred for 30 min. Ammonium persulfate and sodium bisulfite were then added, and the polymerization reaction was carried out at 40°C for 4 h. After the reaction was completed, the mixture was cooled to room temperature and washed three times each with ethanol and deionized water (each time the mass of ethanol was 40% of the mass of deionized water, and each time the mass of deionized water was 50% of the mass of the above deionized water). Finally, the mixture was vacuum dried at 35°C for 24 h to obtain the modified surfactant.

[0074] The preparation method of silanized reinforced materials includes the following steps:

[0075] The reinforcing material, deionized water, and silane coupling agent were mixed in a mass ratio of 1:55:0.3. The reinforcing material was added to the deionized water and stirred for 30 min. Then, it was ultrasonically treated for 2 h (ultrasonic power of 100 W and ultrasonic frequency of 40 kHz). The silane coupling agent was then added and the mixture was placed in a constant temperature water bath at 80 °C for 6 h. After the reaction, the mixture was washed three times each with ethanol and deionized water (each time the mass of ethanol was 20% of the mass of deionized water, and each time the mass of deionized water was 30% of the mass of the deionized water). Finally, the mixture was vacuum dried at 65 °C for 12 h to obtain the silanized reinforcing material. The silane coupling agent was composed of 3-(methacryloyloxy)propyltrimethoxysilane and vinyltriethoxysilane mixed in a mass ratio of 2:1.

[0076] The preparation method of the reinforcing material includes the following steps:

[0077] Carboxylated graphene oxide, deionized water, nanoparticles, and hexadecyltrimethylammonium bromide were mixed uniformly according to a mass ratio of 0.1:100:0.25:0.65. The mixture was then ultrasonically treated for 35 min (ultrasonic power 100W, ultrasonic frequency 40kHz). Nanoparticles and hexadecyltrimethylammonium bromide were then added, and the mixture was stirred at 25℃ for 23 h. After the reaction was completed, the mixture was centrifuged at 10000 rpm for 12 min and washed three times each with ethanol and deionized water (each time the mass of ethanol was 10% of the mass of deionized water, and each time the mass of deionized water was 15% of the mass of the deionized water). Finally, the mixture was freeze-dried at -45℃ for 24 h to obtain the reinforcing material. The nanoparticles were composed of nano-silica, nano-alumina, and nano-titanium dioxide mixed in a mass ratio of 1:0.75:0.45.

[0078] A nano-permeation oil displacement and unblocking agent comprises the following raw materials in parts by weight: 10 parts modified surfactant, 5 parts polycarboxylic acid ammonium salt, 3 parts metal chelating agent, 1.5 parts benzimidazole, 2 parts bactericide, 2.5 parts fatty acid polyethylene glycol ester and 65 parts deionized water.

[0079] Among them, the polycarboxylic acid ammonium salt is composed of diammonium hydrogen citrate and ammonium gluconate in a mass ratio of 1:1; the metal chelating agent is composed of hydroxyethylidene diphosphonic acid and polyepoxysuccinic acid in a mass ratio of 0.75:0.55; and the bactericide is composed of calcium hypochlorite, dodecyl dimethyl benzyl ammonium chloride and tea polyphenols in a mass ratio of 0.65:0.45:1.

[0080] The preparation method includes the following steps:

[0081] Weigh out the raw materials by mass, mix the modified surfactant, polycarboxylic acid ammonium salt, metal chelating agent, benzimidazole, bactericide, fatty acid polyethylene glycol ester and deionized water evenly, and then stir at 35℃ for 3 hours to finally obtain the nano-permeation oil displacement and unblocking agent.

[0082] Example 3

[0083] The specific steps for preparing the modified surfactant are as follows:

[0084] S1: The natural plant gum, deionized water, sodium bicarbonate, and acid anhydride compounds were mixed in a mass ratio of 0.04:40:1.6:0.04. The natural plant gum was added to the deionized water, followed by sodium bicarbonate, and stirred for 1.5 hours. Then, the acid anhydride compounds were added, and the mixture was stirred at 45°C for 5.5 hours. After the reaction, the mixture was added to anhydrous ethanol (the mass of anhydrous ethanol was equal to the mass of deionized water) to precipitate the product. The product was then washed three times with anhydrous ethanol (each time the mass of anhydrous ethanol was 50% of the mass of deionized water), transferred to a dialysis bag (molecular weight cutoff 14 kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at -40°C for 24 hours to obtain the composite material. The natural plant gum was composed of a mixture of guar gum and vetiver gum in a mass ratio of 1.2:0.9; the acid anhydride compounds were composed of a mixture of 2-octenyl succinic anhydride and dodecenyl succinic anhydride in a mass ratio of 0.9:0.6.

[0085] S2: According to the mass ratio of silanized reinforcing material, deionized water, composite material, ammonium persulfate, and sodium bisulfite of 0.5:45:6.1:0.15:0.08, the silanized reinforcing material was added to deionized water and stirred at 15000 rpm for 25 min. The composite material from step S1 was added under a nitrogen atmosphere, and then heated to 45°C and stirred for 35 min. Ammonium persulfate and sodium bisulfite were then added, and the polymerization reaction was carried out at 45°C for 3.5 h. After the reaction was completed, the mixture was cooled to room temperature and washed three times each with ethanol and deionized water (each time the mass of ethanol was 40% of the mass of deionized water, and each time the mass of deionized water was 50% of the mass of the above deionized water). Finally, the mixture was vacuum dried at 40°C for 24 h to obtain the modified surfactant.

[0086] The preparation method of silanized reinforced materials includes the following steps:

[0087] The reinforcing material, deionized water, and silane coupling agent were mixed in a mass ratio of 1.1:60:0.4. The reinforcing material was added to the deionized water and stirred for 35 min. Then, it was ultrasonically treated for 2.5 h (ultrasonic power of 100 W and ultrasonic frequency of 40 kHz). The silane coupling agent was then added and the mixture was placed in a constant temperature water bath at 85 °C for 5.5 h. After the reaction, the mixture was washed three times each with ethanol and deionized water (each time the mass of ethanol was 20% of the mass of deionized water, and each time the mass of deionized water was 30% of the mass of the deionized water). Finally, the mixture was vacuum dried at 70 °C for 12 h to obtain the silanized reinforcing material. The silane coupling agent was composed of 3-(methacryloyloxy)propyltrimethoxysilane and vinyltriethoxysilane mixed in a mass ratio of 2:1.

[0088] The preparation method of the reinforcing material includes the following steps:

[0089] Carboxylated graphene oxide, deionized water, nanoparticles, and hexadecyltrimethylammonium bromide were mixed uniformly according to a mass ratio of 0.12:110:0.3:0.7. The mixture was then ultrasonically treated for 40 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Then, the nanoparticles and hexadecyltrimethylammonium bromide were added, and the mixture was stirred at 30 °C for 22 h. After the reaction was completed, the mixture was centrifuged at 12000 rpm for 10 min and washed three times each with ethanol and deionized water (each time the mass of ethanol was 10% of the mass of deionized water, and each time the mass of deionized water was 15% of the mass of the deionized water). Finally, the mixture was freeze-dried at -40 °C for 24 h to obtain the reinforcing material. The nanoparticles were composed of nano-silica, nano-alumina, and nano-titanium dioxide mixed in a mass ratio of 1.1:0.8:0.5.

[0090] A nano-permeation oil displacement and unblocking agent comprises the following raw materials in parts by weight: 12 parts modified surfactant, 6 parts polycarboxylic acid ammonium salt, 4 parts metal chelating agent, 2 parts triethanolamine, 2.5 parts bactericide, 3 parts octadecyl betaine and 70 parts deionized water.

[0091] Among them, the polycarboxylic acid ammonium salt is composed of diammonium hydrogen citrate and ammonium gluconate in a mass ratio of 1:1; the metal chelating agent is composed of hydroxyethylidene diphosphonic acid and polyepoxysuccinic acid in a mass ratio of 0.8:0.6; and the bactericide is composed of calcium hypochlorite, dodecyl dimethyl benzyl ammonium chloride and tea polyphenols in a mass ratio of 0.7:0.5:1.

[0092] The preparation method includes the following steps:

[0093] Weigh out the raw materials by mass, mix the modified surfactant, polycarboxylic acid ammonium salt, metal chelating agent, triethanolamine, bactericide, octadecyl betaine and deionized water evenly, and then stir at 40℃ for 2 hours to finally obtain the nano-permeation oil displacement and unblocking agent.

[0094] Comparative Example 1

[0095] The difference between this comparative example and Example 3 is that, in the preparation of the modified surfactant, the natural plant gum in step S1 is replaced with vegan gum by mass, while the remaining steps and raw materials are the same as in Example 3.

[0096] S1: According to the mass ratio of vesico-lamin, deionized water, sodium bicarbonate, and acid anhydride compound of 0.04:40:1.6:0.04, vesico-lamin was added to deionized water, followed by sodium bicarbonate, and stirred for 1.5 h. Then, the acid anhydride compound was added, and the mixture was stirred at 45 °C for 5.5 h. After the reaction was completed, the mixture was added to anhydrous ethanol (the mass of anhydrous ethanol was equal to that of deionized water) to precipitate the product. The product was then washed three times with anhydrous ethanol (each time the mass of anhydrous ethanol was 50% of the mass of deionized water), transferred to a dialysis bag (molecular weight cutoff of 14 kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at -40 °C for 24 h to obtain the composite material. The acid anhydride compound was composed of 2-octenyl succinic anhydride and dodecenyl succinic anhydride in a mass ratio of 0.9:0.6.

[0097] Comparative Example 2

[0098] The difference between this comparative example and Example 3 is that, in the preparation of the modified surfactant, the natural plant gum in step S1 is replaced with guar gum by mass, while the remaining steps and raw materials are the same as in Example 3.

[0099] S1: Guar gum, deionized water, sodium bicarbonate, and acid anhydride compounds were mixed in a mass ratio of 0.04:40:1.6:0.04. Guar gum was added to deionized water, followed by sodium bicarbonate, and the mixture was stirred for 1.5 hours. Then, the acid anhydride compounds were added, and the mixture was stirred at 45°C for 5.5 hours. After the reaction was complete, the mixture was added to anhydrous ethanol (the mass of anhydrous ethanol was equal to that of deionized water) to precipitate the product. The product was then washed three times with anhydrous ethanol (each time the mass of anhydrous ethanol was 50% of the mass of deionized water). The product was then transferred to a dialysis bag (molecular weight cutoff of 14 kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at -40°C for 24 hours to obtain the composite material. The acid anhydride compounds were composed of 2-octenyl succinic anhydride and dodecenyl succinic anhydride in a mass ratio of 0.9:0.6.

[0100] Comparative Example 3

[0101] The difference between this comparative example and Example 3 is that, in preparing the modified surfactant, the anhydride compound in step S1 is replaced by an equal mass of 2-octenylsuccinic anhydride, while the remaining steps and raw materials are the same as in Example 3.

[0102] S1: The natural plant gum, deionized water, sodium bicarbonate, and 2-octenyl succinic anhydride were mixed in a mass ratio of 0.04:40:1.6:0.04. The natural plant gum was added to the deionized water, followed by sodium bicarbonate, and stirred for 1.5 hours. Then, 2-octenyl succinic anhydride was added, and the mixture was stirred at 45°C for 5.5 hours. After the reaction was complete, the mixture was added to anhydrous ethanol (the mass of anhydrous ethanol was equal to that of deionized water) to precipitate the product. The product was then washed three times with anhydrous ethanol (each time the mass of anhydrous ethanol was 50% of the mass of deionized water). The product was then transferred to a dialysis bag (molecular weight cutoff of 14 kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at -40°C for 24 hours to obtain the composite material. The natural plant gum was composed of guar gum and vetiver in a mass ratio of 1.2:0.9.

[0103] Comparative Example 4

[0104] The difference between this comparative example and Example 3 is that, in the preparation of the modified surfactant, the anhydride compound in step S1 is replaced by an equal mass of dodecenyl succinic anhydride, while the remaining steps and raw materials are the same as in Example 3.

[0105] S1: The natural plant gum, deionized water, sodium bicarbonate, and dodecenyl succinic anhydride were mixed in a mass ratio of 0.04:40:1.6:0.04. The natural plant gum was added to the deionized water, followed by sodium bicarbonate, and stirred for 1.5 hours. Then, dodecenyl succinic anhydride was added, and the mixture was stirred at 45°C for 5.5 hours. After the reaction was complete, the mixture was added to anhydrous ethanol (the mass of anhydrous ethanol was equal to that of deionized water) to precipitate the product. The product was then washed three times with anhydrous ethanol (each time the mass of anhydrous ethanol was 50% of the mass of deionized water). The product was then transferred to a dialysis bag (molecular weight cutoff of 14 kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at -40°C for 24 hours to obtain the composite material. The natural plant gum was composed of guar gum and vetiver in a mass ratio of 1.2:0.9.

[0106] Comparative Example 5

[0107] The difference between this comparative example and Example 3 is that, in the preparation of the modified surfactant, the silanized reinforcing material in step S2 is directly mixed with the composite material, while the remaining steps and raw materials are the same as in Example 3.

[0108] S2: The silanized reinforcing material, deionized water, and composite material were added to the deionized water at a mass ratio of 0.5:45:6.1. The mixture was stirred at 15,000 rpm for 25 min. The composite material from step S1 was added under a nitrogen atmosphere and stirred at room temperature for 35 min. The mixture was then washed three times each with ethanol and deionized water (each time the mass of ethanol was 40% of the mass of deionized water, and each time the mass of deionized water was 50% of the mass of the deionized water). Finally, the mixture was vacuum dried at 40°C for 24 h to obtain the modified surfactant.

[0109] Comparative Example 6

[0110] The difference between this comparative example and Example 3 is that, in the preparation of the modified surfactant, in step S2, the nanoparticles are composed of a mixture of nano-silica and nano-alumina, while the remaining steps and raw materials are the same as in Example 3.

[0111] The preparation method of the reinforcing material includes the following steps:

[0112] Carboxylated graphene oxide, deionized water, nanoparticles, and hexadecyltrimethylammonium bromide were mixed uniformly according to a mass ratio of 0.12:110:0.3:0.7. The mixture was then ultrasonically treated for 40 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Then, the nanoparticles and hexadecyltrimethylammonium bromide were added, and the mixture was stirred at 30 °C for 22 h. After the reaction was completed, the mixture was centrifuged at 12000 rpm for 10 min and washed three times each with ethanol and deionized water (each time the mass of ethanol was 10% of the mass of deionized water, and each time the mass of deionized water was 15% of the mass of the deionized water). Finally, the mixture was freeze-dried at -40 °C for 24 h to obtain the reinforcing material. The nanoparticles were composed of nano-silica and nano-alumina mixed in a mass ratio of 1.1:1.3.

[0113] Comparative Example 7

[0114] The difference between this comparative example and Example 3 is that, in the preparation of the modified surfactant, in step S2, the nanoparticles are composed of a mixture of nano-silica and nano-titanium dioxide, while the remaining steps and raw materials are the same as in Example 3.

[0115] The preparation method of the reinforcing material includes the following steps:

[0116] Carboxylated graphene oxide, deionized water, nanoparticles, and hexadecyltrimethylammonium bromide were mixed uniformly according to a mass ratio of 0.12:110:0.3:0.7. The mixture was then ultrasonically treated for 40 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). The nanoparticles and hexadecyltrimethylammonium bromide were then added, and the mixture was stirred at 30 °C for 22 h. After the reaction, the mixture was centrifuged at 12000 rpm for 10 min and washed three times each with ethanol and deionized water (each time the mass of ethanol was 10% of the mass of deionized water, and each time the mass of deionized water was 15% of the mass of the deionized water). Finally, the mixture was freeze-dried at -40 °C for 24 h to obtain the reinforcing material. The nanoparticles were composed of nano-silica and nano-titanium dioxide mixed in a mass ratio of 1.1:1.3.

[0117] Comparative Example 8

[0118] The difference between this comparative example and Example 3 is that, in the preparation of the modified surfactant, in step S2, the nanoparticles are composed of a mixture of nano-alumina and nano-titanium dioxide, while the remaining steps and raw materials are the same as in Example 3.

[0119] The preparation method of the reinforcing material includes the following steps:

[0120] Carboxylated graphene oxide, deionized water, nanoparticles, and hexadecyltrimethylammonium bromide were mixed uniformly according to a mass ratio of 0.12:110:0.3:0.7. The mixture was then ultrasonically treated for 40 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). The nanoparticles and hexadecyltrimethylammonium bromide were then added, and the mixture was stirred at 30 °C for 22 h. After the reaction, the mixture was centrifuged at 12000 rpm for 10 min and washed three times each with ethanol and deionized water (each time the mass of ethanol was 10% of the mass of deionized water, and each time the mass of deionized water was 15% of the mass of the deionized water). Finally, the mixture was freeze-dried at -40 °C for 24 h to obtain the reinforcing material. The nanoparticles were composed of nano-alumina and nano-titanium dioxide mixed in a mass ratio of 1.1:1.3.

[0121] Comparative Example 9

[0122] The difference between this comparative example and Example 3 is that, in the preparation of the modified surfactant, in step S2, the reinforcing material is composed of a mixture of carboxylated graphene oxide and nanoparticles, while the remaining steps and raw materials are the same as in Example 3.

[0123] The preparation method of silanized reinforced materials includes the following steps:

[0124] The reinforcing material, deionized water, and silane coupling agent were mixed in a mass ratio of 1.1:60:0.4. The mixture was added to deionized water and stirred for 35 minutes, then sonicated for 2.5 hours (ultrasonic power 100W, ultrasonic frequency 40kHz). Next, the silane coupling agent was added, and the mixture was placed in a constant temperature water bath at 85℃ for 5.5 hours. After the reaction, the mixture was washed three times each with ethanol and deionized water (each time the ethanol mass was 20% of the deionized water mass, and each time the deionized water mass was the same as described above). The mixture (containing 30% water by mass) was vacuum dried at 70°C for 12 hours to obtain a silanized reinforced material. The silane coupling agent was composed of 3-(methacryloyloxy)propyltrimethoxysilane and vinyltriethoxysilane in a mass ratio of 2:1. The reinforcing material was composed of carboxylated graphene oxide and nanoparticles in a mass ratio of 1:1. The nanoparticles were composed of nano-silica, nano-alumina and nano-titanium dioxide in a mass ratio of 1.1:0.8:0.5.

[0125] The corrosion rate, scale inhibition rate, oil washing rate, and self-absorption recovery rate of the nano-permeation oil displacement unblocking agents prepared in Examples 1-3 and Comparative Examples 1-9 were tested. The corrosion rate and scale inhibition rate were tested according to the requirements of HG / T 2387-2007 "Quality Standard for Chemical Cleaning of Industrial Equipment". Oil washing rate test: Crude oil and quartz sand were thoroughly mixed at a mass ratio of 1:6 and dried to constant weight in a 60℃ oven. 5g of the dried oil sand was placed in a 100mL test tube, and a 0.8% unblocking agent solution (40mL) prepared from the nano-permeation oil displacement unblocking agents of Examples 1-3 and Comparative Examples 1-9 was added. After thorough mixing, the test tube was placed in a 60℃ constant temperature oven and left for 48 hours, shaking the test tube once every 12 hours. After standing, the test tube was... The oil and solution washed out were sucked out, and the crude oil adhering to the bottle wall was dabbed off with a cotton swab. The remaining quartz sand was dried in a 60℃ oven to constant weight, and the mass of the quartz sand was weighed. The oil washing rate was calculated according to the following formula: A = (m1-m2) / (m1-m3)×100%, where A is the oil washing rate (%); m1 is the total mass of the test tube and quartz sand before oil washing (g); m2 is the total mass of the test tube and quartz sand after oil washing (g); and m3 is the total mass of the test tube and quartz sand after washing (g). Self-permeation recovery test: The core (Φ2.5×2.5cm) was dried and weighed, and the wet weight was measured after vacuum saturation with experimental water. The pore volume was calculated. Oil-water displacement was performed under reservoir temperature conditions to saturate the core with experimental oil, and the crude oil was allowed to stand for 24 hours to age. The oil saturation was calculated. The experimental water and 0.8% unblocking agent solution were vacuumed for 3 hours to eliminate the adverse effects of dissolved gas on the permeation recovery of the core. The core was then completely immersed in a permeation bottle containing 0.8% unblocking agent solution for permeation experiments. The changes in permeated oil discharge at different time points were recorded, and the permeation recovery rate was calculated using the following formula: η=V O / V W ×100%, where η is the epidermal recovery rate (%); V O The volume of oil discharged during static percolation (cm³) 3 ); V W Volume of saturated oil in the core (cm³) 3 ).

[0126] The test results are shown in Table 1:

[0127] Table 1 Performance parameters of the nano-permeation displacement and unblocking agents prepared in Examples 1-3 and Comparative Examples 1-9

[0128]

[0129] As shown in Table 1, comparing Comparative Examples 1-5 and Example 3, the test results of the nano-permeation oil displacement unblocking agent prepared by replacing the natural plant gum in step S1 with vestigma or guar gum, or replacing the acid anhydride compound in step S1 with 2-octenyl succinic anhydride or dodecenyl succinic anhydride, or directly mixing the silanized reinforcing material with the composite material in step S2, are worse than those of Example 3. This indicates that the natural plant gum composed of vestigma and guar gum has a synergistic effect, which can effectively improve the wettability and stability of the unblocking agent. Qualitative analysis further enhances the oil displacement and penetration capacity of the unblocking agent. Anhydride compounds composed of a mixture of 2-octenyl succinic anhydride and dodecenyl succinic anhydride exhibit a good synergistic effect, helping to reduce oil-water interfacial tension and improve wettability, thereby improving the penetration capacity, oil displacement effect, and stability of the unblocking agent. Combining silanized reinforcing materials with composite materials through chemical reactions can enhance the bonding force between the two, improve the dispersibility of the reinforcing filler, further improve the oil displacement effect and stability of the unblocking agent, enhance its penetration and unblocking performance, and also have a positive impact on corrosion resistance.

[0130] Comparing Comparative Examples 6-9 and Example 3, it can be seen that in step S2, the nanoparticles used are composed of a mixture of nano-silica and nano-alumina, or a mixture of nano-silica and nano-titanium dioxide, or a mixture of nano-alumina and nano-titanium dioxide, or the reinforcing material is a mixture of carboxylated graphene oxide and nanoparticles. The final test results for the nano-penetrating oil displacement and unblocking agent are worse than those of Example 3. This indicates that the nanoparticles composed of a mixture of nano-silica, nano-alumina, and nano-titanium dioxide have a synergistic effect, effectively improving the oil displacement effect, penetration capacity, and stability of the unblocking agent, and enhancing its corrosion resistance and unblocking performance. Uniformly coating the nanoparticles on carboxylated graphene oxide not only improves the dispersibility of the nanoparticles and prevents their aggregation, but also enhances the unblocking performance and stability of the unblocking agent, further improving its oil displacement effect and penetration capacity, and also having a good impact on its corrosion resistance.

[0131] As shown in Table 1, the nano-permeable oil displacement and unblocking agents prepared in Examples 1-3, compared to those prepared in Comparative Examples 1-9, achieved better performance by combining acid anhydride compounds with natural plant gums and then with silanized reinforcing materials to obtain modified surfactants. These modified surfactants, polycarboxylic acid ammonium salts, metal chelating agents, nitrogen-containing compounds, bactericides, dispersants, and deionized water were then mixed and stirred until homogeneous. The nano-permeable oil displacement and unblocking agents prepared in Examples 1-9 did not meet the performance requirements. This indicates that the nano-permeable oil displacement and unblocking agents prepared in this invention not only have better oil displacement effect, permeation capacity, unblocking performance, and stability, but also improve the corrosion resistance and environmental friendliness of the unblocking agent, expanding its application range and demonstrating excellent overall performance.

[0132] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0133] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined by the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A nano-imbibition oil displacement and blockage removal agent, characterized in that, The composition comprises the following raw materials by weight: modified surfactant 8-12 parts, polybasic carboxylic acid ammonium salt 4-6 parts, metal chelating agent 2-4 parts, nitrogen-containing compound 1-2 parts, bactericide 1.5-2.5 parts, dispersant 2-3 parts and deionized water 60-70 parts; The preparation method of the modified surfactant comprises the following steps: S1: obtaining a composite material by combining an acid anhydride compound with natural plant glue; S2: obtaining a modified surfactant by combining the composite material in step S1 with silanized reinforcing material; The natural plant glue is composed of welan gum and guar gum in a mass ratio of 1-1.2:0.7-0.9; The acid anhydride compound is composed of 2-octenyl succinic anhydride and dodecenyl succinic anhydride in a mass ratio of 0.8-0.9:0.5-0.6; Step S2 is specifically: The silanized reinforcing material is added to deionized water and stirred for 25-35 min, the composite material in step S1 is added under a nitrogen atmosphere, then stirring is performed, a catalyst and sodium bisulfite are added, and a polymerization reaction is performed, after the reaction is completed, cooling to room temperature is performed, washing with ethanol and deionized water is performed, and finally vacuum drying is performed to obtain the modified surfactant; The preparation method of the reinforcing material comprises the following steps: The carboxylated graphene oxide and deionized water are uniformly mixed and ultrasonically treated, then nanoparticles and cetyltrimethylammonium bromide are added and stirring reaction is performed, after the reaction is completed, centrifugation is performed, washing with ethanol and deionized water is performed, and finally freeze-drying is performed to obtain the reinforcing material; The nanoparticles are composed of nanosilica, nanoalumina and nanotitanium dioxide in a mass ratio of 0.9-1.1:0.7-0.8:0.4-0.5; The mass ratio of the carboxylated graphene oxide, deionized water, nanoparticles, and cetyltrimethylammonium bromide is 0.08-0.12:90-110:0.2-0.3:0.6-0.7; The nitrogen-containing compound is at least one of benzotriazole, benzimidazole, triethanolamine, and diethylenetriamine.

2. The nano-imbibition oil displacement and blockage removing agent according to claim 1, characterized in that, Step S1 is specifically: The natural plant glue is added to deionized water, sodium bicarbonate is added, and stirring is performed for 1-1.5 h, then the acid anhydride compound is added and stirring reaction is performed, after the reaction is completed, precipitation is performed in anhydrous ethanol, washing is performed with anhydrous ethanol, dialysis is performed with deionized water, and finally freeze-drying is performed to obtain the composite material.

3. The nano-imbibition oil displacement and blockage removing agent according to claim 1, characterized in that, The preparation method of the silanized reinforcing material comprises the following steps: The reinforcing material is added to deionized water and stirred for 25-35 min, then ultrasonic treatment is performed, the silane coupling agent is added, and reaction is performed in a constant-temperature water bath, after the reaction is completed, washing is performed with ethanol and deionized water, and finally vacuum drying is performed to obtain the silanized reinforcing material.

4. The nano-imbibition oil displacement and blockage removing agent according to claim 1, characterized in that, The metal chelating agent is composed of hydroxyethylidene diphosphonic acid and polyepoxysuccinic acid in a mass ratio of 0.7-0.8:0.5-0.

6.

5. The preparation method of the nano-imbibition oil displacement and blockage removing agent according to any one of claims 1-4, characterized in that, The method comprises the following steps: Take the mass of raw materials, mix the modified surfactant, polybasic carboxylic acid ammonium salt, metal chelating agent, nitrogen-containing compound, bactericide, dispersant and deionized water uniformly, then stir at 30-40℃, finally get the nano imbibition oil displacement plugging agent.

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