Nanometer imbibition oil displacement blocking remover and preparation method thereof

Abstract

The invention relates to a nano imbibition oil-displacing blocking remover and a preparation method thereof, and belongs to the technical field of blocking removers, the nano imbibition oil-displacing blocking remover comprises the following raw materials: 8-12 parts of a modified surfactant, 4-6 parts of polybasic carboxylic acid ammonium salt, 2-4 parts of a metal chelating agent, 1-2 parts of a nitrogen-containing compound, 1.5-2.5 parts of a bactericide, 2-3 parts of a dispersant and 60-70 parts of deionized water; according to the technical scheme, the anhydride compound is combined with the natural vegetable gum to obtain the composite material; combining the composite material with a silanization reinforcing material to obtain a modified surfactant; the modified surfactant, the polybasic carboxylic acid ammonium salt, the metal chelating agent, the nitrogen-containing compound, the sterilizing agent, the dispersing agent and the deionized water are mixed and stirred to be uniform, and finally the nano imbibition oil displacement blocking remover is obtained. The modified surfactant effectively improves the oil displacement performance, the imbibition capacity, the stability and the blocking removal performance of the nano imbibition oil displacement blocking remover, and the nano imbibition oil displacement blocking remover is good in corrosion resistance and environmental protection property and good in comprehensive performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plugging removal agents, and particularly relates to a nano imbibition oil displacement plugging removal agent and a preparation method thereof. BACKGROUND

[0002] With the increasing depletion of oil resources, efficient development of low-permeability oil reservoirs has become the focus of current oilfield production. However, due to the characteristics of low porosity, small throat radius, poor matrix permeability, and high clay mineral content, the injection water mining efficiency is low, and it is difficult to produce crude oil. In the long-term injection mining process, calcium and magnesium ions carried in the produced water are easy to form carbonate or sulfate deposits, further plugging the oil reservoir channels, and causing the oil well productivity to decline. In order to improve the oil displacement efficiency of low-permeability oil reservoirs, the oil field generally adds chemical plugging removal agents to the injected water to improve the percolation conditions. Most of the existing plugging removal agents are mainly acidic or strong oxidizing systems, which can alleviate the problem of inorganic scale plugging to some extent, but still have many shortcomings, such as large disturbance to the reservoir pH environment, strong corrosion, poor stability, and safety hazards. In addition, these traditional plugging removal agents have poor adaptability to polymer plugging, biological bacteria plugging and other complex situations, and are difficult to meet the diversified and complex plugging needs of modern oil fields. Therefore, it is urgent to develop a nano imbibition oil displacement plugging removal agent with stable performance and wide application range. This plugging removal agent can effectively reduce the oil-water interfacial tension, improve the rock wettability, and efficiently disperse and remove the plugging materials in the micro-pores without changing the pH value of the reservoir, thereby significantly improving the imbibition capacity and oil recovery of low-permeability oil reservoirs.

[0003] In the prior art, nano imbibition oil displacement plugging removal agents usually add polymers (such as polyacrylamide) to enhance the oil displacement effect, but such polymers are prone to hydrolysis under high temperature conditions, resulting in a significant decrease in their stability and salt resistance, which limits their wide application. In addition, traditional nano imbibition oil displacement plugging removal agents add nanoparticles to improve the plugging removal performance, but due to the high surface energy of nanoparticles, they are easy to agglomerate in the solution, resulting in a significant decrease in the permeability and oil displacement effect of the plugging removal agent. In addition, the agglomerated nanoparticles may block the small pores, exacerbate the damage to the reservoir, and thus affect the overall oil recovery. Moreover, most plugging removal agents contain strong acids, strong oxidizing agents and other chemical components, which have poor environmental protection and may cause harm to the environment and human health during use. SUMMARY

[0004] The present application aims to provide a kind of nanometer imbibition oil displacement agent and its preparation method, by anhydride compound and natural plant glue combination, get composite material;Composite material and silanization reinforcing material are combined, and modified surfactant is obtained;Modified surfactant, polybasic carboxylic acid ammonium salt, metal chelating agent, nitrogen-containing compound, bactericide, dispersant and deionized water are mixed, and stirred uniformly, finally nanometer imbibition oil displacement agent is obtained;Modified surfactant effectively improves the plugging performance, stability, oil displacement effect and imbibition capacity of plugging agent, and improves the corrosion resistance and environmental protection of plugging agent, expands its application range, and overall improves the comprehensive performance of plugging agent.

[0005] The technical problems to be solved by the present application are as follows: in the prior art, nanometer imbibition oil displacement agent usually uses the way of adding polymer (such as polyacrylamide) to enhance oil displacement effect, but such polymer is easy to hydrolyze under high temperature conditions, which leads to significant decrease in stability and salt resistance, limiting its wide application;And the traditional nanometer imbibition oil displacement agent improves the plugging performance by adding nano particles, but due to the high surface energy of nano particles, agglomeration phenomenon is easy to occur in solution, which leads to significant decrease in penetration capacity and oil displacement effect of plugging agent, in addition, agglomerated nano particles may block small pores, aggravate reservoir damage, and further affect overall crude oil recovery.

[0006] The object of the present application can be achieved by the following technical solutions: A kind of nanometer imbibition oil displacement agent, comprising the following weight parts of raw materials: 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 modified surfactant comprises the following steps: S1: by anhydride compound and natural plant glue combination, get composite material; S2: the composite material in step S1 is combined with silanization reinforcing material, and modified surfactant is obtained.

[0007] Further, step S1 is specifically: Natural plant glue is added to deionized water, then sodium bicarbonate is added, and stirred for 1-1.5 h, then anhydride compound is added, and stirring reaction is carried out, after reaction, it is precipitated in anhydrous ethanol, then washed with anhydrous ethanol, dialyzed with deionized water, and finally freeze-dried to obtain composite material.

[0008] In the above reaction process, the natural plant glue has a hydroxyl group, the acid anhydride compound has an acid anhydride group, the hydroxyl group in the natural plant glue can be combined with the acid anhydride group in the acid anhydride compound, the natural plant glue and the acid anhydride compound are combined together, and finally the composite material is obtained.

[0009] Further, the mass ratio of the natural plant glue, deionized water, sodium bicarbonate and acid anhydride compound is 0.02-0.04:20-40:1.4-1.6:0.02-0.04.

[0010] Further, the natural plant glue is composed of welan gum and guar gum mixed according to a mass ratio of 1-1.2:0.7-0.9.

[0011] Further, the acid anhydride compound is composed of 2-octenyl succinic anhydride and dodecenyl succinic anhydride mixed according to a mass ratio of 0.8-0.9:0.5-0.6.

[0012] Further, the stirring reaction temperature is 35-45℃, and the time is 5.5-6.5h.

[0013] Further, the freeze-drying temperature is minus 50-40℃.

[0014] Further, step S2 is specifically: The silanized reinforcing material is added to deionized water and stirred for 25-35min, the composite material in step S1 is added under a nitrogen atmosphere, then stirring is performed, the catalyst and sodium bisulfite are added, and 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.

[0015] In the above reaction process, the silanized reinforcing material has a carbon-carbon double bond, and the composite material also has a carbon-carbon double bond, the carbon-carbon double bond on the silanized reinforcing material can be polymerized with the carbon-carbon double bond in the composite material under the action of the catalyst, thereby combining the composite material with the silanized reinforcing material together, and finally obtaining the modified surfactant.

[0016] Further, 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.

[0017] Further, the catalyst is ammonium persulfate.

[0018] Further, the stirring temperature is 35-45℃, and the time is 25-35min.

[0019] Further, the temperature of the polymerization reaction is 35-45℃, and the time is 3.5-4.5h.

[0020] Further, the temperature of the vacuum drying is 30-40℃.

[0021] Further, the preparation method of the silanized reinforcing material comprises the following steps: The reinforcing material is added into deionized water and stirred for 25-35min, then ultrasonic treatment is performed, then the silane coupling agent is added and placed in a constant temperature water bath for reaction, after the reaction is completed, washed with ethanol and deionized water, and finally vacuum dried to obtain the silanized reinforcing material.

[0022] In the above reaction process, the surface of the reinforcing material has hydroxyl groups, and the silane coupling agent produces silanol groups after hydrolysis, the silanol groups in the silane coupling agent can combine with the hydroxyl groups on the reinforcing material, the silane coupling agent is grafted onto the surface of the reinforcing material, and finally the silanized reinforcing material is obtained.

[0023] Further, the mass ratio of the reinforcing material, deionized water and silane coupling agent is 0.9-1.1:50-60:0.2-0.4.

[0024] Further, the silane coupling agent is composed of 3-(methacryloyloxy) propyl trimethoxysilane and vinyl triethoxysilane in a mass ratio of 2:1.

[0025] Further, the ultrasonic treatment time is 1.5-2.5h.

[0026] Further, the reaction temperature of the constant temperature water bath is 75-85℃, and the reaction time is 5.5-6.5h.

[0027] Further, the temperature of the vacuum drying is 60-70℃.

[0028] Further, the preparation method of the reinforcing material comprises the following steps: The carboxylated graphene oxide and deionized water are mixed uniformly and ultrasonic treatment is performed, then the nanoparticles and cetyltrimethylammonium bromide are added and stirred for reaction, after the reaction is completed, centrifuged, washed with ethanol and deionized water, and finally freeze-dried to obtain the reinforcing material.

[0029] In the above reaction process, the cetyltrimethylammonium bromide can be adsorbed on the surface of the nanoparticles, so that the surface of the nanoparticles has a positive charge in the aqueous solution, the carboxylated graphene oxide has a negative charge on the surface in the aqueous solution, and 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, so that the nanoparticles are uniformly coated on the surface of the carboxylated graphene oxide, and finally the reinforcing material is obtained.

[0030] Further, 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.

[0031] Further, the nanoparticles are composed of nano-silicon dioxide, nano-aluminum oxide and nano-titanium dioxide in a mass ratio of 0.9-1.1:0.7-0.8:0.4-0.5.

[0032] Further, the ultrasonic treatment time is 30-40 min.

[0033] Further, the stirring reaction temperature is 20-30 DEG C, and the time is 22-24 h.

[0034] A preparation method of a nano-imbibition oil displacement and blockage removal agent comprises the following steps: The modified surfactant, polybasic ammonium salt, metal chelating agent, nitrogen-containing compound, bactericide, dispersant and deionized water are mixed uniformly, then stirring is carried out at 30-40 DEG C, and finally the nano-imbibition oil displacement and blockage removal agent is obtained.

[0035] Further, the polybasic ammonium salt is composed of diammonium hydrogen citrate and ammonium glucarate in a mass ratio of 1:1.

[0036] Further, 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.

[0037] Further, the nitrogen-containing compound is at least one of benzotriazole, benzimidazole, triethanolamine and diethylenetriamine.

[0038] Further, the bactericide is composed of calcium hypochlorite, dodecyl dimethyl benzyl ammonium chloride and tea polyphenol in a mass ratio of 0.6-0.7:0.4-0.5:1.

[0039] Further, the dispersant is at least one of sodium dodecylbenzenesulfonate, fatty acid polyethylene glycol ester, octadecyl betaine and sodium polyacrylate.

[0040] Further, the stirring time is 2-4 h.

[0041] A nano-imbibition oil displacement and blockage removal agent is prepared by the above-mentioned preparation method of the nano-imbibition oil displacement and blockage removal agent.

[0042] The beneficial effects of the present application are: (1) In the technical scheme of the present application, a composite material is obtained by combining an acid anhydride compound with natural plant glue; the natural plant glue is composed of xanthan gum and guar gum, and the two have a synergistic effect; both the xanthan gum and the guar gum have good thickening effect, and can improve the fluidity of the solution, further improve the stability of the plugging agent, and enhance the oil displacement effect and imbibition capacity; the acid anhydride compound is composed of 2-octenyl succinic anhydride and dodecenyl succinic anhydride, and the two also have a good synergistic effect, which is helpful to significantly reduce the oil-water interfacial tension, is conducive to the more effective displacement of crude oil from the rock pores, better improves the oil displacement effect of the plugging agent, and increases the self-imbibition recovery rate and stability; the acid anhydride compound is combined with the natural plant glue, and the two have good binding force and can form an amphiphilic surfactant, which can significantly reduce the oil-water interfacial tension, help to improve the rock wettability, enhance the stability and salt resistance of the plugging agent, effectively improve the oil displacement effect and imbibition capacity of the plugging agent, and has good environmental protection, and can also provide reaction sites for subsequent reactions, further enhancing the overall performance of the plugging agent.

[0043] (2) In the technical scheme of the present application, the composite material is combined with a silanized reinforcing material to obtain a modified surfactant; the silanized reinforcing material is prepared by grafting a silane coupling agent to a reinforcing material; the silane coupling agent can improve the dispersibility of the reinforcing material, prevent agglomeration, and increase the binding force between the composite material and the reinforcing material; the reinforcing material is prepared by combining carboxylated graphene oxide and nanoparticles; the nanoparticles are uniformly coated on the surface of the carboxylated graphene oxide, which can further increase the dispersibility of the nanoparticles, prevent agglomeration, and effectively enhance the plugging performance and stability of the plugging agent, further improve the oil displacement effect and imbibition capacity of the plugging agent; the nanoparticles are composed of nano-silicon dioxide, nano-aluminum oxide and nano-titanium dioxide, which have a synergistic effect, can improve the wettability of the rock surface, reduce the oil-water interfacial tension, enhance the stability and salt resistance of the plugging agent, further improve the imbibition capacity, oil displacement effect and plugging performance of the plugging agent, and can also enhance the corrosion resistance and environmental protection; the modified surfactant, polybasic carboxylic acid ammonium salt, metal chelating agent, nitrogen-containing compound, bactericide, dispersant and deionized water are mixed and uniformly stirred, and finally the nano-imbibition oil displacement plugging agent is obtained; the modified surfactant improves the overall performance of the nano-imbibition oil displacement plugging agent.

[0044] (3) In the technical scheme of the present application, the modified surfactant is obtained by combining an acid anhydride compound with a natural plant glue and then combining the modified surfactant with a silanization reinforcing material. The modified surfactant, an ammonium salt of a polycarboxylic acid, a metal chelating agent, a nitrogen-containing compound, a bactericide, a dispersant and deionized water are mixed and uniformly stirred, and finally the nano imbibition oil displacement plugging agent is obtained. The nano imbibition oil displacement plugging agent not only can better improve the plugging performance, oil displacement effect, stability and imbibition capacity of the plugging agent, but also has good corrosion resistance and environmental protection, expands the application range, and has good overall comprehensive performance. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0046] The specific parameters of the raw materials used in the present application are as follows: 2-octenyl succinic anhydride, CAS number: 42482-06-4, product number: BD00823234, provided by Shanghai Bide Pharmaceutical Technology Co., Ltd.; dodecenyl succinic anhydride, CAS number: 26544-38-7, product number: BD02147955, provided by Shanghai Bide Pharmaceutical Technology Co., Ltd.; welan gum, provided by Zhengzhou Jiuting Chemical Product Co., Ltd.; guar gum, provided by Henan Jiqian Biological Technology Co., Ltd.; carboxylated graphene oxide, item number: BK2020062233-01, provided by Suzhou Kaifa New Material Technology Co., Ltd.; nano silicon dioxide, CAS number: 7631-86-9, product number: A61745, provided by Saen Chemical Technology (Shanghai) Co., Ltd.; nano aluminum oxide, model number: CY-L30, particle size: 30 nm, provided by Hangzhou Jiupeng New Material Co., Ltd.; nano titanium dioxide (anatase type nano titanium dioxide), model number: VK-TA18, particle size: 20 nm, provided by Xuancheng Jingrui New Material Co., Ltd.; polyepoxysuccinic acid, CAS number: 51274-37-4, provided by Jiangsu Puleisi Biological Technology Co., Ltd.; sodium polyacrylate, CAS number: 9003-04-7, product number: P434406, provided by Shanghai Aladdin Biochem Technology Co., Ltd.

[0047] Example 1 The modified surfactant is prepared by the following specific steps: S1: according to the mass ratio of natural plant glue, deionized water, sodium bicarbonate, acid anhydride compound is 0.02:20:1.4:0.02, the natural plant glue is added to the deionized water, then the sodium bicarbonate is added and stirred for 1h, then the acid anhydride compound is added, and stirred at 35℃ for 6.5h, after the reaction is completed, it is added to anhydrous ethanol for precipitation (the mass of anhydrous ethanol is equal to the mass of deionized water), then washed with anhydrous ethanol for 3 times (the mass of anhydrous ethanol is 50% of the mass of deionized water each time), moved to a dialysis bag (the molecular weight cut-off is 14kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at minus 50℃ for 24h, to obtain a composite material, wherein the natural plant glue is composed of welan gum and guar gum according to a mass ratio of 1:0.7; the acid anhydride compound is composed of 2-octenyl succinic anhydride and dodecenyl succinic anhydride according to a mass ratio of 0.8:0.5; S2: according to the mass ratio of silanized reinforcing material, deionized water, composite material, ammonium persulfate, sodium bisulfite is 0.3:35:5.9:0.1:0.06, the silanized reinforcing material is added to the deionized water and stirred at a speed of 10000rpm for 35min, the composite material in step S1 is added under nitrogen atmosphere, then heated to 35℃ and stirred for 35min, then ammonium persulfate and sodium bisulfite are added, and the polymerization reaction is carried out at 35℃ for 4.5h, after the reaction is completed, it is cooled to room temperature, washed with ethanol and deionized water for 3 times respectively (the mass of ethanol is 40% of the mass of deionized water each time, and the mass of deionized water is 50% of the mass of the above deionized water each time), and finally vacuum dried at 30℃ for 24h to obtain a modified surfactant; The preparation method of the silanized reinforcing material comprises the following steps: According to the mass ratio of reinforcing material, deionized water, silane coupling agent is 0.9:50:0.2, the reinforcing material is added to the deionized water and stirred for 25min, then ultrasonic treated for 1.5h (ultrasonic power is 100W, ultrasonic frequency is 40kHz), then the silane coupling agent is added and placed in a constant temperature water bath at 75℃ for 6.5h, after the reaction is completed, it is washed with ethanol and deionized water for 3 times respectively (the mass of ethanol is 20% of the mass of deionized water each time, and the mass of deionized water is 30% of the mass of the above deionized water each time), and finally vacuum dried at 60℃ for 12h to obtain a silanized reinforcing material, wherein the silane coupling agent is composed of 3-(methacryloyloxy)propyl trimethoxysilane and vinyl triethoxysilane according to a mass ratio of 2:1; The preparation method of the reinforcing material comprises the following steps: According to the mass ratio of carboxylated graphene oxide, deionized water, nanoparticles, cetyltrimethylammonium bromide is 0.08:90:0.2:0.6, the carboxylated graphene oxide and deionized water are mixed uniformly, and ultrasonic treatment is carried out for 30 min (ultrasonic power is 100 W, ultrasonic frequency is 40 kHz), then nanoparticles and cetyltrimethylammonium bromide are added, and stirring reaction is carried out at 20℃ for 24h, after the reaction is completed, centrifugation is carried out at 8000rpm for 15 min, and then ethanol and deionized water are used for washing respectively for 3 times (the mass of ethanol is 10% of the mass of deionized water each time, and the mass of deionized water is 15% of the mass of the above deionized water each time), finally, freeze-drying is carried out at minus 50℃ for 24h, and the reinforcing material is obtained, wherein the nanoparticles are composed of nanosilica, nanoalumina and nanotitanium dioxide according to the mass ratio of 0.9:0.7:0.4; A nano-osmotic oil displacement and plugging removing agent, comprising the following raw materials in parts by weight: modified surfactant 8 parts, polybasic carboxylic acid ammonium salt 4 parts, metal chelating agent 2 parts, benzene propyl triazole 1 part, bactericide 1.5 parts, sodium dodecyl benzene sulfonate 2 parts and deionized water 60 parts; The polybasic carboxylic acid ammonium salt is composed of diammonium hydrogen citrate and ammonium glucarate according to the mass ratio of 1:1; the metal chelating agent is composed of hydroxyethylidene diphosphonic acid and polyepoxysuccinic acid according to the mass ratio of 0.7:0.5; the bactericide is composed of calcium hypochlorite, dodecyl dimethyl benzyl ammonium chloride and tea polyphenol according to the mass ratio of 0.6:0.4:1; The preparation method comprises the following steps: The raw materials are weighed, the modified surfactant, polybasic carboxylic acid ammonium salt, metal chelating agent, benzene propyl triazole, bactericide, sodium dodecyl benzene sulfonate and deionized water are mixed uniformly, then stirring is carried out at 30℃ for 4h, and finally the nano-osmotic oil displacement and plugging removing agent is obtained.

[0048] Example 2 The modified surfactant is prepared, and the specific steps are as follows: S1: according to the mass ratio of natural plant gum, deionized water, sodium bicarbonate, acid anhydride compound is 0.03:30:1.5:0.03, the natural plant gum is added to the deionized water, then the sodium bicarbonate is added and stirred for 1.2h, then the acid anhydride compound is added and stirred at 40℃ for 6h, after the reaction is completed, it is added to anhydrous ethanol for precipitation (the mass of anhydrous ethanol is equal to the mass of deionized water), then washed with anhydrous ethanol for 3 times (the mass of anhydrous ethanol is 50% of the mass of deionized water each time), moved to a dialysis bag (the molecular weight cut-off is 14kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at minus 45℃ for 24h, to obtain a composite material, wherein the natural plant gum is composed of welan gum and guar gum according to a mass ratio of 1.1:0.8; the acid anhydride compound is composed of 2-octenyl succinic anhydride and dodecenyl butane dicarboxylic anhydride according to a mass ratio of 0.85:0.55; S2: according to the mass ratio of silanized reinforcing material, deionized water, composite material, ammonium persulfate, sodium bisulfite is 0.4:40:6:0.12:0.07, the silanized reinforcing material is added to the deionized water and stirred at a speed of 12000rpm for 30min, the composite material in step S1 is added under nitrogen atmosphere, then heated to 40℃ and stirred for 30min, then ammonium persulfate and sodium bisulfite are added, and the polymerization reaction is carried out at 40℃ for 4h, after the reaction is completed, it is cooled to room temperature, washed with ethanol and deionized water for 3 times respectively (the mass of ethanol is 40% of the mass of deionized water each time, and the mass of deionized water is 50% of the mass of the above deionized water each time), and finally vacuum dried at 35℃ for 24h to obtain a modified surfactant; The preparation method of the silanized reinforcing material comprises the following steps: According to the mass ratio of reinforcing material, deionized water, silane coupling agent is 1:55:0.3, the reinforcing material is added to the deionized water and stirred for 30min, then ultrasonic treated for 2h (ultrasonic power is 100W, ultrasonic frequency is 40kHz), then the silane coupling agent is added and placed in a constant temperature water bath at 80℃ for 6h, after the reaction is completed, it is washed with ethanol and deionized water for 3 times respectively (the mass of ethanol is 20% of the mass of deionized water each time, and the mass of deionized water is 30% of the mass of the above deionized water each time), and finally vacuum dried at 65℃ for 12h to obtain a silanized reinforcing material, wherein the silane coupling agent is composed of 3-(methacryloyloxy) propyl trimethoxysilane and vinyl triethoxysilane according to a mass ratio of 2:1; The preparation method of the reinforcing material comprises the following steps: According to the mass ratio of carboxylated graphene oxide, deionized water, nanoparticles, cetyltrimethylammonium bromide is 0.1:100:0.25:0.65, the carboxylated graphene oxide and deionized water are mixed uniformly, and ultrasonic treatment is carried out for 35min (ultrasonic power is 100W, ultrasonic frequency is 40kHz), then nanoparticles and cetyltrimethylammonium bromide are added, and stirring reaction is carried out at 25℃ for 23h, after the reaction is completed, centrifugation is carried out at 10000rpm for 12min, and then ethanol and deionized water are used for washing respectively for 3 times (the mass of ethanol is 10% of the mass of deionized water each time, and the mass of deionized water is 15% of the mass of the above deionized water each time), finally, freeze-drying is carried out at minus 45℃ for 24h, and the reinforcing material is obtained, wherein the nanoparticles are composed of nanosilica, nanoalumina and nanotitanium dioxide according to the mass ratio of 1:0.75:0.45; A nano-osmotic oil displacement and plugging removing agent, comprising the following raw materials by weight: modified surfactant 10 parts, polybasic carboxylic acid ammonium salt 5 parts, metal chelating agent 3 parts, benzimidazole 1.5 parts, bactericide 2 parts, fatty acid polyethylene glycol ester 2.5 parts and deionized water 65 parts; The polybasic carboxylic acid ammonium salt is composed of diammonium hydrogen citrate and ammonium glucarate according to the mass ratio of 1:1; the metal chelating agent is composed of hydroxyethylidene diphosphonic acid and polyepoxysuccinic acid according to the mass ratio of 0.75:0.55; the bactericide is composed of calcium hypochlorite, dodecyl dimethyl benzyl ammonium chloride and tea polyphenol according to the mass ratio of 0.65:0.45:1; The preparation method comprises the following steps: The raw materials are weighed, the modified surfactant, the polybasic carboxylic acid ammonium salt, the metal chelating agent, the benzimidazole, the bactericide, the fatty acid polyethylene glycol ester and the deionized water are mixed uniformly, then stirring is carried out at 35℃ for 3h, and finally the nano-osmotic oil displacement and plugging removing agent is obtained.

[0049] Example 3 The modified surfactant is prepared, and the specific steps are as follows: S1: according to the mass ratio of natural plant glue, deionized water, sodium bicarbonate, acid anhydride compound is 0.04:40:1.6:0.04, the natural plant glue is added to the deionized water, then the sodium bicarbonate is added and stirred for 1.5h, then the acid anhydride compound is added and stirred at 45℃ for 5.5h, after the reaction is completed, it is added to anhydrous ethanol for precipitation (the mass of anhydrous ethanol is equal to the mass of deionized water), then washed with anhydrous ethanol for 3 times (the mass of anhydrous ethanol is 50% of the mass of deionized water each time), moved to a dialysis bag (the molecular weight cut-off is 14kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at minus 40℃ for 24h to obtain a composite material, wherein the natural plant glue is composed of welan gum and guar gum according to a mass ratio of 1.2:0.9; the acid anhydride compound is composed of 2-octenyl succinic anhydride and dodecenyl succinic anhydride according to a mass ratio of 0.9:0.6; S2: according to the mass ratio of silanized reinforcing material, deionized water, composite material, ammonium persulfate, sodium bisulfite is 0.5:45:6.1:0.15:0.08, the silanized reinforcing material is added to the deionized water and stirred at a speed of 15000rpm for 25min, the composite material in step S1 is added under nitrogen atmosphere, then heated to 45℃ and stirred for 35min, then ammonium persulfate and sodium bisulfite are added, and the polymerization reaction is carried out at 45℃ for 3.5h, after the reaction is completed, it is cooled to room temperature, washed with ethanol and deionized water for 3 times respectively (the mass of ethanol is 40% of the mass of deionized water each time, and the mass of deionized water is 50% of the mass of the above deionized water each time), and finally vacuum dried at 40℃ for 24h to obtain a modified surfactant; The preparation method of the silanized reinforcing material comprises the following steps: According to the mass ratio of reinforcing material, deionized water, silane coupling agent is 1.1:60:0.4, the reinforcing material is added to the deionized water and stirred for 35min, then ultrasonic treated for 2.5h (ultrasonic power is 100W, ultrasonic frequency is 40kHz), then the silane coupling agent is added and placed in a constant temperature water bath at 85℃ for reaction for 5.5h, after the reaction is completed, it is washed with ethanol and deionized water for 3 times respectively (the mass of ethanol is 20% of the mass of deionized water each time, and the mass of deionized water is 30% of the mass of the above deionized water each time), and finally vacuum dried at 70℃ for 12h to obtain a silanized reinforcing material, wherein the silane coupling agent is composed of 3-(methacryloyloxy)propyl trimethoxysilane and vinyl triethoxysilane according to a mass ratio of 2:1; The preparation method of the reinforcing material comprises the following steps: According to the mass ratio of carboxylated graphene oxide, deionized water, nanoparticles, cetyltrimethylammonium bromide is 0.12:110:0.3:0.7, the carboxylated graphene oxide and deionized water are mixed uniformly, and ultrasonic treatment is carried out for 40min (ultrasonic power is 100W, ultrasonic frequency is 40kHz), then nanoparticles and cetyltrimethylammonium bromide are added, and stirring reaction is carried out at 30℃ for 22h, after the reaction is completed, centrifugation is carried out at 12000rpm for 10min, and then ethanol and deionized water are used for washing respectively for 3 times (the mass of ethanol is 10% of the mass of deionized water each time, and the mass of deionized water is 15% of the mass of the above deionized water each time), finally, freeze-drying is carried out at minus 40℃ for 24h, and the reinforcing material is obtained, wherein the nanoparticles are composed of nanosilica, nanoalumina and nanotitanium dioxide according to the mass ratio of 1.1:0.8:0.5; A nano-osmotic oil displacement and plugging agent, comprising the following raw materials by weight: modified surfactant 12 parts, polybasic ammonium carboxylate 6 parts, metal chelating agent 4 parts, triethanolamine 2 parts, bactericide 2.5 parts, octadecyl betaine 3 parts and deionized water 70 parts; Wherein, the polybasic ammonium carboxylate is composed of diammonium hydrogen citrate and ammonium glucarate according to the mass ratio of 1:1; the metal chelating agent is composed of hydroxyethylidene diphosphonic acid and polyepoxysuccinic acid according to the mass ratio of 0.8:0.6; the bactericide is composed of calcium hypochlorite, dodecyl dimethyl benzyl ammonium chloride and tea polyphenol according to the mass ratio of 0.7:0.5:1; The preparation method comprises the following steps: The raw materials are weighed, the modified surfactant, polybasic ammonium carboxylate, metal chelating agent, triethanolamine, bactericide, octadecyl betaine and deionized water are mixed uniformly, then stirring is carried out at 40℃ for 2h, and finally the nano-osmotic oil displacement and plugging agent is obtained.

[0050] Comparative Example 1 The difference between this comparative example and Example 3 is that when preparing the modified surfactant, the natural plant glue in step S1 is replaced by welan gum with the same mass, and the remaining steps and raw materials are implemented synchronously with Example 3. S1: according to the mass ratio of xanthan gum, deionized water, sodium bicarbonate, acid anhydride compound is 0.04:40:1.6:0.04, xanthan gum is added to deionized water, then sodium bicarbonate is added and stirred for 1.5h, then acid anhydride compound is added and stirred at 45℃ for 5.5h, after the reaction is completed, it is added to anhydrous ethanol for precipitation (the mass of anhydrous ethanol is equal to the mass of deionized water), then washed with anhydrous ethanol for 3 times (the mass of anhydrous ethanol is 50% of the mass of deionized water), moved to a dialysis bag (the molecular weight cut-off is 14kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at minus 40℃ for 24h to obtain a composite material, wherein the acid anhydride compound is composed of 2-octenyl succinic anhydride and dodecenyl succinic anhydride according to the mass ratio of 0.9:0.6.

[0051] Comparative Example 2 The difference between this comparative example and Example 3 is that when preparing the modified surfactant, the natural plant gum in step S1 is replaced by guar gum with the same mass, and the remaining steps and raw materials are implemented synchronously with Example 3. S1: according to the mass ratio of guar gum, deionized water, sodium bicarbonate, acid anhydride compound is 0.04:40:1.6:0.04, xanthan gum is added to deionized water, then sodium bicarbonate is added and stirred for 1.5h, then acid anhydride compound is added and stirred at 45℃ for 5.5h, after the reaction is completed, it is added to anhydrous ethanol for precipitation (the mass of anhydrous ethanol is equal to the mass of deionized water), then washed with anhydrous ethanol for 3 times (the mass of anhydrous ethanol is 50% of the mass of deionized water), moved to a dialysis bag (the molecular weight cut-off is 14kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at minus 40℃ for 24h to obtain a composite material, wherein the acid anhydride compound is composed of 2-octenyl succinic anhydride and dodecenyl succinic anhydride according to the mass ratio of 0.9:0.6.

[0052] Comparative Example 3 The difference between this comparative example and Example 3 is that when preparing the modified surfactant, the acid anhydride compound in step S1 is replaced by 2-octenyl succinic anhydride with the same mass, and the remaining steps and raw materials are implemented synchronously with Example 3. S1: according to the mass ratio of natural plant gum, deionized water, sodium bicarbonate, 2-octenyl succinic anhydride is 0.04:40:1.6:0.04, the natural plant gum is added to the deionized water, then the sodium bicarbonate is added and stirred for 1.5h, then the 2-octenyl succinic anhydride is added and stirred at 45℃ for 5.5h, after the reaction is completed, it is added to anhydrous ethanol for precipitation (the mass of anhydrous ethanol is equal to the mass of deionized water), then washed with anhydrous ethanol for 3 times (the mass of anhydrous ethanol is 50% of the mass of deionized water each time), moved to a dialysis bag (the molecular weight cut-off is 14kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at minus 40℃ for 24h to obtain a composite material, wherein the natural plant gum is composed of welan gum and guar gum according to the mass ratio of 1.2:0.9.

[0053] Comparative Example 4 The difference between this comparative example and Example 3 is that when preparing the modified surfactant, the acid anhydride compound in step S1 is replaced with dodecenyl succinic anhydride in equal mass, and the remaining steps and raw materials are implemented synchronously with Example 3. S1: according to the mass ratio of natural plant gum, deionized water, sodium bicarbonate, dodecenyl succinic anhydride is 0.04:40:1.6:0.04, the natural plant gum is added to the deionized water, then the sodium bicarbonate is added and stirred for 1.5h, then the dodecenyl succinic anhydride is added and stirred at 45℃ for 5.5h, after the reaction is completed, it is added to anhydrous ethanol for precipitation (the mass of anhydrous ethanol is equal to the mass of deionized water), then washed with anhydrous ethanol for 3 times (the mass of anhydrous ethanol is 50% of the mass of deionized water each time), moved to a dialysis bag (the molecular weight cut-off is 14kDa), dialyzed with deionized water for 3 days, and finally freeze-dried at minus 40℃ for 24h to obtain a composite material, wherein the natural plant gum is composed of welan gum and guar gum according to the mass ratio of 1.2:0.9.

[0054] Comparative Example 5 The difference between this comparative example and Example 3 is that when preparing the modified surfactant, the silanized reinforcing material in step S2 is directly mixed with the composite material, and the remaining steps and raw materials are implemented synchronously with Example 3. S2: according to the mass ratio of silanized reinforcing material, deionized water, composite material is 0.5:45:6.1, the silanized reinforcing material is added to the deionized water and stirred at a speed of 15000rpm for 25min, the composite material in step S1 is added under nitrogen atmosphere, then stirred at room temperature for 35min, washed with ethanol and deionized water for 3 times each (the mass of ethanol is 40% of the mass of deionized water each time, and the mass of deionized water is 50% of the mass of the above deionized water each time), and finally vacuum dried at 40℃ for 24h to obtain a modified surfactant.

[0055] Comparative Example 6 The comparative example is different from example 3 in that, in the preparation of the modified surfactant, in step S2, the nanoparticles are composed of a mixture of nanosilica and nanoalumina, and the remaining steps and raw materials are the same as in example 3. The preparation method of the reinforcing material comprises the following steps: According to the mass ratio of carboxylated graphene oxide, deionized water, nanoparticles, and cetyltrimethylammonium bromide of 0.12:110:0.3:0.7, the carboxylated graphene oxide and deionized water are mixed uniformly and ultrasonic treated for 40 min (ultrasonic power is 100 W and ultrasonic frequency is 40 kHz), then the nanoparticles and cetyltrimethylammonium bromide are added and stirred at 30°C for 22 h, after the reaction is completed, centrifuged at 12000 rpm for 10 min, washed with ethanol and deionized water for 3 times respectively (the mass of ethanol is 10% of the mass of deionized water each time, and the mass of deionized water is 15% of the mass of the above deionized water each time), and finally freeze-dried at minus 40°C for 24 h to obtain the reinforcing material, wherein the nanoparticles are composed of a mixture of nanosilica and nanoalumina according to a mass ratio of 1.1:1.3.

[0056] Comparative example 7 The comparative example is different from example 3 in that, in the preparation of the modified surfactant, in step S2, the nanoparticles are composed of a mixture of nanosilica and nanotitanium dioxide, and the remaining steps and raw materials are the same as in example 3. The preparation method of the reinforcing material comprises the following steps: According to the mass ratio of carboxylated graphene oxide, deionized water, nanoparticles, and cetyltrimethylammonium bromide of 0.12:110:0.3:0.7, the carboxylated graphene oxide and deionized water are mixed uniformly and ultrasonic treated for 40 min (ultrasonic power is 100 W and ultrasonic frequency is 40 kHz), then the nanoparticles and cetyltrimethylammonium bromide are added and stirred at 30°C for 22 h, after the reaction is completed, centrifuged at 12000 rpm for 10 min, washed with ethanol and deionized water for 3 times respectively (the mass of ethanol is 10% of the mass of deionized water each time, and the mass of deionized water is 15% of the mass of the above deionized water each time), and finally freeze-dried at minus 40°C for 24 h to obtain the reinforcing material, wherein the nanoparticles are composed of a mixture of nanosilica and nanotitanium dioxide according to a mass ratio of 1.1:1.3.

[0057] Comparative example 8 The comparative example is different from example 3 in that, in the preparation of the modified surfactant, in step S2, the nanoparticles are composed of a mixture of nanoalumina and nanotitanium dioxide, and the remaining steps and raw materials are the same as in example 3. The preparation method of the reinforcing material comprises the following steps: According to the mass ratio of carboxylated graphene oxide, deionized water, nanoparticles, and cetyltrimethylammonium bromide is 0.12:110:0.3:0.7, the carboxylated graphene oxide and deionized water are mixed uniformly, and ultrasonic treatment is carried out for 40 min (ultrasonic power is 100 W, ultrasonic frequency is 40 kHz), then the nanoparticles and cetyltrimethylammonium bromide are added, and stirring reaction is carried out at 30°C for 22h, after the reaction is completed, centrifugation is carried out at 12000 rpm for 10 min, and then washing is carried out with ethanol and deionized water for 3 times (the mass of ethanol is 10% of the mass of deionized water each time, and the mass of deionized water is 15% of the mass of the above deionized water each time), and finally freeze-drying is carried out at minus 40°C for 24h, to obtain the reinforcing material, wherein the nanoparticles are composed of nano-alumina and nano-titanium dioxide with a mass ratio of 1.1:1.3.

[0058] Comparative Example 9 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 carboxylated graphene oxide and nanoparticles, and the remaining steps and raw materials are the same as in Example 3. The preparation method of the silanized reinforcing material comprises the following steps: According to the mass ratio of reinforcing material, deionized water, and silane coupling agent is 1.1:60:0.4, the reinforcing material is added to the deionized water and stirred for 35 min, then ultrasonic treatment is carried out for 2.5h (ultrasonic power is 100 W, ultrasonic frequency is 40 kHz), then the silane coupling agent is added, and placed in a constant temperature water bath at 85°C for 5.5h, after the reaction is completed, washing is carried out with ethanol and deionized water for 3 times (the mass of ethanol is 20% of the mass of deionized water each time, and the mass of deionized water is 30% of the mass of the above deionized water each time), and finally vacuum drying is carried out at 70°C for 12h, to obtain the silanized reinforcing material, wherein the silane coupling agent is composed of 3-(methacryloyloxy) propyl trimethoxysilane and vinyl triethoxysilane with a mass ratio of 2:1, wherein the reinforcing material is composed of carboxylated graphene oxide and nanoparticles with a mass ratio of 1:1; the nanoparticles are composed of nano-silicon dioxide, nano-alumina, and nano-titanium dioxide with a mass ratio of 1.1:0.8:0.5.

[0059] The nano-imbibition oil displacement and plug removal agents prepared in Examples 1-3 and Comparative Examples 1-9 were tested for corrosion rate, scale inhibition rate, oil washing rate and self-imbibition recovery rate. The corrosion rate and scale inhibition rate were tested according to the requirements in HG / T 2387-2007 "Quality Standard for Chemical Cleaning of Industrial Equipment". The oil washing rate was tested as follows: crude oil and quartz sand were mixed in a mass ratio of 1:6, dried in a 60°C oven to constant weight, 5g of the dried oil sand was taken and placed in a 100mL test tube, 40mL of 0.8% plug removal agent solution prepared from the nano-imbibition oil displacement and plug removal agent prepared in Examples 1-3 and Comparative Examples 1-9 was added, mixed thoroughly and placed in a 60°C constant temperature oven, shaken every 12h, the oil and solution washed out were sucked out after standing, the crude oil adhered to the bottle wall was wiped out with a cotton swab, the remaining quartz sand was dried in a 60°C oven to constant weight, the mass of the quartz sand was measured, and the oil washing rate was calculated according to the following formula: A= (m1-m2) / (m1-m3) x 100%, wherein 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). The self-imbibition recovery rate was tested as follows: the core (Φ2.5x2.5cm) was dried and weighed, vacuum saturated with experimental water and weighed to calculate the pore volume; the core was saturated with experimental oil at the oil reservoir temperature and allowed to stand for 24h to age the oil, and the oil saturation was calculated; the experimental water and 0.8% plug removal agent solution were vacuumed for 3h to eliminate the adverse effects of dissolved gas in the experimental water and 0.8% plug removal agent solution on the imbibition oil displacement of the core, the core was completely immersed in the imbibition bottle containing the 0.8% plug removal agent solution, and the imbibition experiment was performed; the change in the imbibition oil discharge at different time periods was recorded, and the imbibition recovery rate was calculated according to the following formula: η=V O / V W x 100%, wherein η is the imbibition recovery rate (%); V O is the volume of the oil discharged in the static imbibition process (cm 3 ); and V W is the volume of the oil saturated in the core (cm 3 ).

[0060] The test results are shown in Table 1. Table 1 Performance parameters of the nano-imbibition oil displacement and plug removal agents prepared in Examples 1-3 and Comparative Examples 1-9 From the data in Table 1, it can be seen that, by comparing Comparative Examples 1-5 and Example 3, when the natural plant glue in step S1 is replaced with an equal amount of welan gum or guar gum, or the anhydride compound in step S1 is replaced with an equal amount of 2-octenyl succinic anhydride or dodecenyl succinic anhydride, or the silanized reinforcing material is directly mixed with the composite material in step S2, the test results of the nano-imbibition oil displacement and plugging agent prepared finally are poorer than those of Example 3, indicating that the natural plant glue composed of welan gum and guar gum has a synergistic effect, which can effectively improve the wettability and stability of the plugging agent, and further improve the oil displacement effect and imbibition capacity of the plugging agent; the anhydride compound composed of 2-octenyl succinic anhydride and dodecenyl succinic anhydride has a good synergistic effect, which helps to reduce the oil-water interfacial tension and improve the wettability, thereby improving the imbibition capacity, oil displacement effect and stability of the plugging agent; the silanized reinforcing material is combined with the composite material through chemical reaction, which 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 plugging agent, and improve the imbibition capacity and plugging performance of the plugging agent, and has a good effect on the corrosion resistance; From the comparison of Comparative Examples 6-9 and Example 3, it can be seen that, in step S2, the nanoparticles are composed of a mixture of nanosilica and nanoalumina, or the nanoparticles are composed of a mixture of nanosilica and nanotitanium dioxide, or the nanoparticles are composed of a mixture of nanoalumina and nanotitanium dioxide, or the reinforcing material is composed of a mixture of carboxylated graphene oxide and nanoparticles, and finally the nano-imbibition oil displacement and plugging agent is prepared, and the test results are poorer than those of Example 3, indicating that the nanoparticles composed of a mixture of nanosilica, nanoalumina and nanotitanium dioxide have a synergistic effect, which can effectively improve the oil displacement effect, imbibition capacity and stability of the plugging agent, and can enhance the corrosion resistance and plugging performance of the plugging agent; the nanoparticles are uniformly coated on the carboxylated graphene oxide, which not only improves the dispersibility of the nanoparticles and prevents their agglomeration, but also enhances the plugging performance and stability of the plugging agent, further improves the oil displacement effect and imbibition capacity of the plugging agent, and has a good effect on the corrosion resistance of the plugging agent.

[0061] As shown in Table 1, the nano imbibition oil displacement and plugging agent prepared in Examples 1-3 is combined with anhydride compounds and natural plant glue, and then combined with silanization enhancement materials to obtain a modified surfactant, and the modified surfactant, polybasic ammonium salt, metal chelating agent, nitrogen-containing compound, bactericide, dispersant and deionized water are mixed and uniformly stirred to obtain the nano imbibition oil displacement and plugging agent, which meets the performance requirements, while the nano imbibition oil displacement and plugging agent prepared in Comparative Examples 1-9 does not meet the performance requirements, which indicates that the nano imbibition oil displacement and plugging agent prepared in the application has good oil displacement effect, imbibition capacity, plugging performance and stability, improves the corrosion resistance and environmental protection of the plugging agent, expands the application range, and has good overall comprehensive performance.

[0062] In the description of the specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the application. In the specification, the illustrative description 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.

[0063] The above is only an example and description of the application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific embodiments, as long as they do not deviate from the application or exceed the scope defined by the application, which shall belong to the protection scope of the application.

Claims

1. A nano-imbibition oil displacement and blockage removal agent, characterized in that, The method comprises the following steps: S1: combining the acid anhydride compound with the natural plant glue to obtain a composite material; S2: combining the composite material in step S1 with the silanized reinforcing material to obtain the modified surfactant. The step S1 is specifically:

2. The nano-imbibition oil displacement and blockage removal agent according to claim 1, characterized in that, The natural plant glue is mixed with deionized water, and then sodium bicarbonate is added and stirred for 1-1.5 h. Then the acid anhydride compound is added and stirred to react. After the reaction is completed, the product is precipitated in anhydrous ethanol, washed with anhydrous ethanol, dialyzed with deionized water, and finally freeze-dried to obtain the composite 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.

3. The nano-imbibition oil displacement and blockage removing agent according to claim 2, characterized in that, 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.

4. The nano-imbibition oil displacement and blockage removing agent according to claim 2, characterized in that, The step S2 is specifically:

5. The nano-imbibition oil displacement and blockage removal agent according to claim 1, characterized in that, 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, and then stirred. The catalyst and sodium bisulfite are added and polymerized. After the reaction is completed, the product is cooled to room temperature, washed with ethanol and deionized water, and finally vacuum dried to obtain the modified surfactant. The preparation method of the silanized reinforcing material comprises the following steps:

6. The nano-imbibition oil displacement and blockage removing agent according to claim 5, characterized in that, The reinforcing material is added to deionized water and stirred for 25-35 min, and then ultrasonic treatment is performed. The silane coupling agent is added and reacted in a constant-temperature water bath. After the reaction is completed, the product is washed with ethanol and deionized water, and finally vacuum dried to obtain the silanized reinforcing material. The preparation method of the reinforcing material comprises the following steps:

7. The nano-imbibition oil displacement and blockage removing agent according to claim 6, characterized in that, The carboxylated graphene oxide and deionized water are mixed uniformly and ultrasonically treated. The nanoparticles and cetyltrimethylammonium bromide are added and stirred to react. After the reaction is completed, the product is centrifuged, washed with ethanol and deionized water, and finally freeze-dried to obtain the reinforcing material. The nanoparticles are composed of nano-silicon dioxide, nano-aluminum oxide and nano-titanium dioxide in a mass ratio of 0.9-1.1:0.7-0.8:0.4-0.

5.

8. The nano-imbibition oil displacement and blockage removing agent according to claim 7, 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.

9. The nano-imbibition oil displacement and blockage removing agent according to claim 1, characterized in that, The method comprises the following steps:

10. A method for preparing the nano-imbibition oil displacement and blockage removing agent according to any one of claims 1-9, characterized in that, The modified surfactant, the ammonium polycarboxylate, the metal chelating agent, the nitrogen-containing compound, the bactericide, the dispersant and the deionized water are mixed uniformly, and then stirred at 30-40°C to obtain the nano-imbibition oil displacement and plugging removal agent. ​

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