A viscoelastic polymer particle oil displacement agent and preparation method thereof

Abstract

The invention relates to the technical field of oil production, and in particular to a viscoelastic polymer particle oil-displacing agent and a preparation method thereof. The viscoelastic polymer particle oil-displacing agent comprises the following raw materials in weight percentage: 32-36% of a modified polymer, 12-14% of loaded particles, 4-6% of n-pentanol and 5-7% of cyclohexane, with the balance being water. The polymer is modified and compounded with the loaded particles, thereby solving the problem of insufficient oil-displacing performance of the existing polymer oil-displacing agent under the condition of stronger heterogeneity and more dispersed residual oil distribution.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum extraction, and in particular to a viscoelastic polymer particle oil displacement agent and a preparation method thereof. Background Art

[0002] Polyacrylamide, a commonly used polymer oil-displacing agent, is prone to flow along large pores or high permeability zones when used in polymer flooded reservoirs with severe heterogeneity, making it difficult to achieve a significant oil-displacing effect. Although cross-linked polyacrylamide can effectively block large pores, it has poor deformation ability and cannot be transported in the reservoir, thus failing to achieve an effective oil-displacing effect. Summary of the invention

[0003] The object of the present invention is to provide a viscoelastic polymer particle oil-displacing agent and a preparation method thereof, which solves the problem of insufficient oil-displacing performance of existing polymer oil-displacing agents when the heterogeneity is stronger and the residual oil distribution is more dispersed by modifying the polymer and compounding it with load particles.

[0004] The object of the present invention can be achieved by the following technical scheme: a method for preparing a viscoelastic polymer particle oil-displacing agent: weigh the following raw materials in weight percentage: 32-36% of a modified polymer, 12-14% of loaded particles, 4-6% of n-pentanol and 5-7% of cyclohexane, with the balance being water, and mix the modified polymer, loaded particles, n-pentanol, cyclohexane and water to prepare a viscoelastic polymer particle oil-displacing agent;

[0005] The modified polymer is prepared by the following steps:

[0006] Step A1: 4-aminopiperidine, 1,5-dibromopentane, potassium carbonate and tetrahydrofuran were mixed, and the mixture was reacted for 12 hours at a stirring rate of 80-100 rpm and a temperature of 50° C. to obtain intermediate 1; intermediate 1, 4-vinylbenzaldehyde and anhydrous ethanol were mixed, and the mixture was reacted for 6-8 hours at a stirring rate of 80-100 rpm and a temperature of 70° C. to obtain intermediate 2;

[0007] The dosage ratio of 4-aminopiperidine, 1,5-dibromopentane and potassium carbonate is 0.04-0.05 mol: 0.042-0.052 mol: 0.8-1 g; the dosage ratio of the intermediate 1,4-vinylbenzaldehyde and anhydrous ethanol is 0.04-0.045 mol: 0.042-0.048 mol: 80-100 mL;

[0008] During the reaction, the piperidine group in 4-aminopiperidine reacts with 1,5-dibromopentane to undergo a cyclization reaction to form an azospiro ring structure to obtain intermediate 1, and the amino group in intermediate 1 reacts with the aldehyde group in 4-vinylbenzaldehyde to obtain intermediate 2;

[0009] Step A2: 6-methylisocytosine and dimethyl sulfoxide are mixed, stirred at a stirring rate of 100-120 rpm and a temperature of 170° C., ethyl isocyanate acrylate is added, cooled to room temperature, and reacted for 1-1.5 hours to obtain intermediate 3; acrylamide, intermediate 2, intermediate 3 and deionized water are mixed, stirred at a stirring rate of 60-80 rpm and a temperature of 50° C., ammonium persulfate solution is added, and reacted for 3-4 hours to obtain a modified polymer;

[0010] The dosage ratio of 6-methylisocytosine and ethyl isocyanate acrylate is 0.03-0.04 mol: 0.03-0.04 mol; the mass concentration of the ammonium persulfate solution is 0.1 g / mL, and the dosage ratio of acrylamide, intermediate 2, intermediate 3 and ammonium persulfate solution is 0.04-0.05 mol: 0.02-0.022 mol: 0.01-0.012 mol: 24-26 mL;

[0011] During the reaction, the primary amine in 6-methylisocytosine reacts with the isocyanate group in isocyanate ethyl acrylate to form a ureidopyrimidone structure to obtain intermediate 3. Under the condition of ammonium persulfate as an initiator, acrylamide, intermediate 2 and intermediate 3 double bonds react to obtain a modified polymer.

[0012] The loaded particles are prepared by the following steps:

[0013] Step B1: Carboxylated silica microspheres and toluene are mixed and ultrasonically dispersed for 15 minutes, and 4,4'-methylenebis(phenyl isocyanate) and dibutyltin dilaurate are added under stirring at a rate of 80-100 rpm and a temperature of 60°C, and the mixture is reacted for 8-10 hours, and then β-cyclodextrin is added and the reaction is continued for 4-5 hours to obtain a precursor;

[0014] The dosage ratio of carboxylated silica microspheres, 4,4'-methylenebis(phenyl isocyanate), dibutyltin dilaurate and β-cyclodextrin is 2.8-3 g: 0.04-0.05 mol: 0.2-0.3 mL: 6-8 g;

[0015] During the reaction, the carboxyl groups in the carboxylated silica microspheres react with the isocyanate groups in 4,4'-methylenebis(phenyl isocyanate) to form an amide structure, and the isocyanate groups are introduced. The isocyanate groups then react with the hydroxyl groups in β-cyclodextrin to form a carbamate structure, thereby obtaining a precursor.

[0016] Step B2: sodium montmorillonite, carboxymethyl chitosan and deionized water are mixed, ultrasonically dispersed for 15 minutes, reacted for 5-6 hours at a stirring rate of 120-150 rpm and a temperature of 70°C to obtain modified montmorillonite, and the modified montmorillonite is mixed with glutaraldehyde solution, reacted for 30 minutes at a stirring rate of 180-240 rpm and room temperature, and then adamantane amine is added, and the temperature is raised to 50°C, and the reaction is continued for 6-7 hours to obtain loaded montmorillonite;

[0017] The dosage ratio of sodium montmorillonite, carboxymethyl chitosan and deionized water is 2-2.2g: 0.04-0.06g: 25-30mL; the mass fraction of glutaraldehyde solution is 25%, and the dosage ratio of modified montmorillonite, glutaraldehyde solution and adamantane amine is 2-2.2g: 100-110mL: 0.6-0.8g;

[0018] In the reaction process, carboxymethyl chitosan is used as a modifier to perform intercalation modification on sodium montmorillonite to obtain modified montmorillonite, and then glutaraldehyde is used as a crosslinking agent to crosslink and solidify the carboxymethyl chitosan, and the glutaraldehyde is grafted by the reaction of the amino group in the adamantane amine to obtain the loaded montmorillonite;

[0019] Step B3: The precursor, the loaded montmorillonite and the deionized water were mixed and ultrasonically dispersed for 10 minutes, and stirred for 30 minutes at a stirring rate of 120-180 rpm and room temperature to obtain loaded particles;

[0020] The ratio of precursor, loaded montmorillonite and deionization is 0.7-0.8g: 2.4-2.6g: 30-35mL;

[0021] During the reaction, the precursor is fixed on the loaded montmorillonite through the host-guest inclusion complex between the cyclodextrin structure in the precursor and the adamantane structure in the loaded montmorillonite, thereby obtaining loaded particles.

[0022] The invention has the beneficial effects as follows: the invention discloses a viscoelastic polymer particle oil-displacing agent and a preparation method thereof. The invention solves the problem that the existing polymer oil-displacing agent has insufficient oil-displacing performance when the heterogeneity is stronger and the residual oil distribution is more dispersed by modifying the polymer and compounding with the loaded particles. During the use of the viscoelastic polymer particle oil-displacing agent, when the modified polymer and the loaded particles flow along the large pores or the high permeability zone, the modified polymer and the loaded particles can dynamically adjust the heterogeneous pores in real time and block the large pore throat channels due to the hydrogen bonding between the ureidopyrimidone in the modified polymer and the loaded particle carboxymethyl chitosan. At the same time, due to the host-guest structure of the loaded particles themselves, the precursors are gradually released, and the structure of the precursors themselves enables them to effectively change the oil-water interfacial tension, thereby achieving the oil-displacing effect. At the same time, since the large pore throat channels are blocked, the subsequent displacement is also turned to the small pore throats, changing the distribution of the residual oil. The quaternary ammonium salt nitrogen spirocyclic structure of the modified polymer itself can change the oil-water interfacial tension to a certain extent, thereby achieving the purpose of improving the recovery rate. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1 A method for preparing a viscoelastic polymer particle oil displacement agent: Weigh the following raw materials in weight percentage: 32% modified polymer, 12% supported particles, 4% n-pentanol and 5% cyclohexane, and the balance is water, and mix the modified polymer, supported particles, n-pentanol, cyclohexane and water to prepare a viscoelastic polymer particle oil displacement agent;

[0025] The modified polymer is prepared by the following steps:

[0026] Step A1: 4-aminopiperidine, 1,5-dibromopentane, potassium carbonate and tetrahydrofuran were mixed, and the mixture was reacted at a stirring rate of 80 rpm and a temperature of 50° C. for 12 h to obtain intermediate 1; intermediate 1, 4-vinylbenzaldehyde and anhydrous ethanol were mixed, and the mixture was reacted at a stirring rate of 80 rpm and a temperature of 70° C. for 6 h to obtain intermediate 2;

[0027] The ratio of 4-aminopiperidine, 1,5-dibromopentane and potassium carbonate is 0.04 mol: 0.042 mol: 0.8 g; the ratio of intermediate 1, 4-vinylbenzaldehyde and anhydrous ethanol is 0.04 mol: 0.042 mol: 80 mL;

[0028] Step A2: 6-methylisocytosine and dimethyl sulfoxide were mixed, stirred at a stirring rate of 100 rpm and a temperature of 170°C, ethyl isocyanate acrylate was added, cooled to room temperature, and reacted for 1 hour to obtain intermediate 3; acrylamide, intermediate 2, intermediate 3 and deionized water were mixed, stirred at a stirring rate of 60 rpm and a temperature of 50°C, ammonium persulfate solution was added, and reacted for 3 hours to obtain a modified polymer;

[0029] The dosage ratio of 6-methylisocytosine and ethyl isocyanate acrylate is 0.03 mol: 0.03 mol; the mass concentration of ammonium persulfate solution is 0.1 g / mL; the dosage ratio of acrylamide, intermediate 2, intermediate 3 and ammonium persulfate solution is 0.04 mol: 0.02 mol: 0.01 mol: 24 mL;

[0030] The loaded particles are prepared by the following steps:

[0031] Step B1: commercially available Beike nano carboxylated silica microspheres and toluene were mixed and ultrasonically dispersed for 15 minutes, and 4,4'-methylenebis(phenyl isocyanate) and dibutyltin dilaurate were added under stirring at a rate of 80 rpm and a temperature of 60°C, and the reaction was continued for 8 hours, and then β-cyclodextrin was added and the reaction was continued for 4 hours to obtain a precursor;

[0032] The amount ratio of carboxylated silica microspheres, 4,4'-methylenebis(phenyl isocyanate), dibutyltin dilaurate and β-cyclodextrin is 2.8 g: 0.04 mol: 0.2 mL: 6 g;

[0033] Step B2: Mix commercially available sodium-montmorillonite from Kaiqi, commercially available carboxymethyl chitosan from Caiwei and deionized water, perform ultrasonic dispersion for 15 minutes, react for 5 hours at a stirring rate of 120 rpm and a temperature of 70°C to obtain modified montmorillonite, mix the modified montmorillonite with a glutaraldehyde solution, react for 30 minutes at a stirring rate of 180 rpm and room temperature, then add adamantane amine, raise the temperature to 50°C, and continue to react for 6 hours to obtain loaded montmorillonite;

[0034] The dosage ratio of sodium montmorillonite, carboxymethyl chitosan and deionized water is 2g:0.04g:25-30mL; the mass fraction of glutaraldehyde solution is 25%, and the dosage ratio of modified montmorillonite, glutaraldehyde solution and adamantane amine is 2g:100mL:0.6g;

[0035] Step B3: The precursor, the loaded montmorillonite and the deionized water were mixed and ultrasonically dispersed for 10 min, and stirred for 30 min at a stirring rate of 120 rpm and room temperature to obtain loaded particles;

[0036] The dosage ratio of precursor, loaded montmorillonite and deionizer is 0.7g:2.4g:30mL.

[0037] Example 2 A method for preparing a viscoelastic polymer particle oil displacement agent: Weigh the following raw materials in weight percentage: 36% modified polymer, 12% supported particles, 4% n-pentanol and 7% cyclohexane, with the balance being water, and mix the modified polymer, supported particles, n-pentanol, cyclohexane and water to prepare a viscoelastic polymer particle oil displacement agent;

[0038] The modified polymer is prepared by the following steps:

[0039] Step A1: 4-aminopiperidine, 1,5-dibromopentane, potassium carbonate and tetrahydrofuran were mixed, and the mixture was reacted at a stirring rate of 80 rpm and a temperature of 50° C. for 12 h to obtain intermediate 1; intermediate 1, 4-vinylbenzaldehyde and anhydrous ethanol were mixed, and the mixture was reacted at a stirring rate of 100 rpm and a temperature of 70° C. for 6-8 h to obtain intermediate 2;

[0040] The ratio of 4-aminopiperidine, 1,5-dibromopentane and potassium carbonate is 0.04 mol: 0.042 mol: 1 g; the ratio of intermediate 1,4-vinylbenzaldehyde and anhydrous ethanol is 0.04 mol: 0.042 mol: 100 mL;

[0041] Step A2: 6-methylisocytosine and dimethyl sulfoxide were mixed, stirred at a stirring rate of 100 rpm and a temperature of 170°C, ethyl isocyanate acrylate was added, cooled to room temperature, and reacted for 1.5 hours to obtain intermediate 3; acrylamide, intermediate 2, intermediate 3 and deionized water were mixed, stirred at a stirring rate of 60 rpm and a temperature of 50°C, ammonium persulfate solution was added, and reacted for 4 hours to obtain a modified polymer;

[0042] The dosage ratio of 6-methylisocytosine and ethyl isocyanate acrylate is 0.03 mol: 0.03 mol; the mass concentration of ammonium persulfate solution is 0.1 g / mL; the dosage ratio of acrylamide, intermediate 2, intermediate 3 and ammonium persulfate solution is 0.04 mol: 0.022 mol: 0.01 mol: 26 mL;

[0043] The loaded particles are prepared by the following steps:

[0044] Step B1: Mix commercially available Beike nano carboxylated silica microspheres and toluene and ultrasonically disperse for 15 minutes, stir at a stirring rate of 80 rpm and a temperature of 60°C, add 4,4'-methylenebis(phenyl isocyanate) and dibutyltin dilaurate, react for 10 hours, then add β-cyclodextrin and continue to react for 4-5 hours to obtain a precursor;

[0045] The amount ratio of carboxylated silica microspheres, 4,4'-methylenebis(phenyl isocyanate), dibutyltin dilaurate and β-cyclodextrin is 2.8 g: 0.05 mol: 0.2 mL: 8 g;

[0046] Step B2: Mix commercially available sodium-montmorillonite from Kaiqi, commercially available carboxymethyl chitosan from Caiwei and deionized water, perform ultrasonic dispersion for 15 minutes, react for 5 hours at a stirring rate of 150 rpm and a temperature of 70°C to obtain modified montmorillonite, mix the modified montmorillonite with a glutaraldehyde solution, react for 30 minutes at a stirring rate of 180 rpm and room temperature, then add adamantane amine, raise the temperature to 50°C, and continue to react for 7 hours to obtain loaded montmorillonite;

[0047] The dosage ratio of sodium montmorillonite, carboxymethyl chitosan and deionized water is 2.2g:0.04g:25mL; the mass fraction of glutaraldehyde solution is 25%, and the dosage ratio of modified montmorillonite, glutaraldehyde solution and adamantane is 2.2g:100mL:0.6g;

[0048] Step B3: The precursor, the loaded montmorillonite and the deionized water were mixed and ultrasonically dispersed for 10 min, and stirred for 30 min at a stirring rate of 180 rpm and room temperature to obtain loaded particles;

[0049] The dosage ratio of precursor, loaded montmorillonite and deionizer is 0.8g:2.4g:35mL.

[0050] Example 3 A method for preparing a viscoelastic polymer particle oil displacement agent: Weigh the following raw materials in weight percentage: 36% modified polymer, 14% supported particles, 6% n-pentanol and 7% cyclohexane, and the balance is water, mix the modified polymer, supported particles, n-pentanol, cyclohexane and water to prepare a viscoelastic polymer particle oil displacement agent;

[0051] The modified polymer is prepared by the following steps:

[0052] Step A1: 4-aminopiperidine, 1,5-dibromopentane, potassium carbonate and tetrahydrofuran were mixed, and the mixture was reacted for 12 hours at a stirring rate of 100 rpm and a temperature of 50° C. to obtain intermediate 1; intermediate 1, 4-vinylbenzaldehyde and anhydrous ethanol were mixed, and the mixture was reacted for 8 hours at a stirring rate of 100 rpm and a temperature of 70° C. to obtain intermediate 2;

[0053] The ratio of 4-aminopiperidine, 1,5-dibromopentane and potassium carbonate is 0.05 mol: 0.052 mol: 1 g; the ratio of intermediate 1,4-vinylbenzaldehyde and anhydrous ethanol is 0.045 mol: 0.048 mol: 100 mL;

[0054] Step A2: 6-methylisocytosine and dimethyl sulfoxide were mixed, stirred at a stirring rate of 120 rpm and a temperature of 170°C, ethyl isocyanate acrylate was added, cooled to room temperature, and reacted for 1.5 hours to obtain intermediate 3; acrylamide, intermediate 2, intermediate 3 and deionized water were mixed, stirred at a stirring rate of 80 rpm and a temperature of 50°C, ammonium persulfate solution was added, and reacted for 4 hours to obtain a modified polymer;

[0055] The dosage ratio of 6-methylisocytosine and ethyl isocyanate acrylate is 0.04 mol: 0.04 mol; the mass concentration of ammonium persulfate solution is 0.1 g / mL; the dosage ratio of acrylamide, intermediate 2, intermediate 3 and ammonium persulfate solution is 0.05 mol: 0.022 mol: 0.012 mol: 26 mL;

[0056] The loaded particles are prepared by the following steps:

[0057] Step B1: Mix commercially available Beike nano carboxylated silica microspheres and toluene and disperse them by ultrasonication for 15 minutes. Stir and add 4,4'-methylenebis(phenyl isocyanate) and dibutyltin dilaurate at a stirring rate of 100 rpm and a temperature of 60°C. React for 10 hours, then add β-cyclodextrin and continue to react for 5 hours to obtain a precursor.

[0058] The ratio of carboxylated silica microspheres, 4,4'-methylenebis(phenyl isocyanate), dibutyltin dilaurate and β-cyclodextrin is 3 g: 0.05 mol: 0.3 mL: 8 g;

[0059] Step B2: Mix commercially available sodium-montmorillonite from Kaiqi, commercially available carboxymethyl chitosan from Caiwei and deionized water, perform ultrasonic dispersion for 15 minutes, react for 6 hours at a stirring rate of 150 rpm and a temperature of 70°C to obtain modified montmorillonite, mix the modified montmorillonite with a glutaraldehyde solution, react for 30 minutes at a stirring rate of 240 rpm and room temperature, then add adamantane amine, raise the temperature to 50°C, and continue to react for 7 hours to obtain loaded montmorillonite;

[0060] The dosage ratio of sodium montmorillonite, carboxymethyl chitosan and deionized water is 2.2g:0.06g:30mL; the mass fraction of glutaraldehyde solution is 25%, and the dosage ratio of modified montmorillonite, glutaraldehyde solution and adamantane is 2.2g:110mL:0.8g;

[0061] Step B3: The precursor, the loaded montmorillonite and the deionized water were mixed and ultrasonically dispersed for 10 min, and stirred for 30 min at a stirring rate of 180 rpm and room temperature to obtain loaded particles;

[0062] The dosage ratio of precursor, loaded montmorillonite and deionizer is 0.8g:2.6g:35mL.

[0063] Comparative Example 1 Compared with Example 3, this comparative example is to remove 1,5-dibromopentane in the preparation process of the modified polymer in Example 3, and the other steps are the same.

[0064] Comparative Example 2 Compared with Example 3, this comparative example is different in that the intermediate 3 in the preparation process of the modified polymer in Example 3 is replaced by ethyl acrylate, and the other steps are the same.

[0065] Comparative Example 3 Compared with Example 3, this comparative example is to remove the precursor used in the preparation of the modified polymer in Example 3, and the other steps are the same.

[0066] Take a viscoelastic polymer particle oil-displacing agent prepared in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2 and Comparative Example 3, mix 18g of surfactant oil-displacing agent and 1000mL of deionized water, stir at 50°C for 12h to prepare an oil-displacing system, and use a viscometer 0 # The viscosity of the solution was measured at a rotor speed of 6 rpm and a temperature of 75 °C. -1 The viscosity was measured after shearing for 60 min under the conditions. According to SY / T 5153-2007, the core flooding experiment was carried out at a temperature of 75 °C and the permeabilities were 50×10 -3 μm 2 ,300×10 -3 μm 2 and 800×10 -3 μm 2 The core gradient combination is used to form a heterogeneous artificial core. The water flooding and polymer flooding methods are first used for testing and the recovery rate is calculated. Then the oil flooding system is used for the third oil flooding and the third oil flooding recovery rate is calculated. The test results are as follows:

[0067] Test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Viscosity (mPa∙s) 45.79 46.90 47.54 45.63 36.08 46.27 Viscosity after shear (mPa∙s) 21.98 22.11 22.42 21.50 12.38 21.86 The third flooding oil recovery rate (%) 20.97 21.18 21.49 19.92 15.17 17.53

[0068] It can be seen from the test results in the table shown that when Example 1, Example 2 and Example 3 are compared with Comparative Example 1, Comparative Example 2 and Comparative Example 3, Comparative Example 1 removes 1,5-dibromopentane during the preparation of the modified polymer in Example 3, and its performance is reduced due to the lack of nitrogen spirocyclic structure and quaternary ammonium salt structure. Comparative Example 2 replaces intermediate 3 in the preparation of the modified polymer in Example 3 with ethyl acrylate, and its performance is reduced due to the lack of ureidopyrimidone structure. Comparative Example 3 removes the precursor during the preparation of the modified polymer in Example 3, and its performance is reduced due to the lack of precursor.

[0069] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0070] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a viscoelastic polymer particle oil-displacing agent, characterized in that: The method comprises the following steps: weighing the following raw materials in weight percentage: 32-36% of a modified polymer, 12-14% of supported particles, 4-6% of n-pentanol and 5-7% of cyclohexane, with the balance being water, and mixing the modified polymer, supported particles, n-pentanol, cyclohexane and water to prepare a viscoelastic polymer particle oil displacement agent; The modified polymer is prepared by the following steps: Step A1: 4-aminopiperidine, 1,5-dibromopentane, potassium carbonate and tetrahydrofuran were mixed, and the mixture was reacted for 12 hours at a stirring rate of 80-100 rpm and a temperature of 50° C. to obtain intermediate 1; intermediate 1, 4-vinylbenzaldehyde and anhydrous ethanol were mixed, and the mixture was reacted for 6-8 hours at a stirring rate of 80-100 rpm and a temperature of 70° C. to obtain intermediate 2; Step A2: 6-methylisocytosine and dimethyl sulfoxide are mixed, stirred at a stirring rate of 100-120 rpm and a temperature of 170° C., ethyl isocyanate acrylate is added, cooled to room temperature, and reacted for 1-1.5 hours to obtain intermediate 3; acrylamide, intermediate 2, intermediate 3 and deionized water are mixed, stirred at a stirring rate of 60-80 rpm and a temperature of 50° C., ammonium persulfate solution is added, and reacted for 3-4 hours to obtain a modified polymer; The loaded particles are prepared by the following steps: Step B1: Carboxylated silica microspheres and toluene are mixed and ultrasonically dispersed for 15 minutes, and 4,4'-methylenebis(phenyl isocyanate) and dibutyltin dilaurate are added under stirring at a rate of 80-100 rpm and a temperature of 60°C, and the mixture is reacted for 8-10 hours, and then β-cyclodextrin is added and the reaction is continued for 4-5 hours to obtain a precursor; Step B2: sodium montmorillonite, carboxymethyl chitosan and deionized water are mixed, ultrasonically dispersed for 15 minutes, reacted for 5-6 hours at a stirring rate of 120-150 rpm and a temperature of 70°C to obtain modified montmorillonite, and the modified montmorillonite is mixed with glutaraldehyde solution, reacted for 30 minutes at a stirring rate of 180-240 rpm and room temperature, and then adamantane amine is added, and the temperature is raised to 50°C, and the reaction is continued for 6-7 hours to obtain loaded montmorillonite; Step B3: The precursor, loaded montmorillonite and deionized water were mixed and ultrasonically dispersed for 10 minutes, and stirred for 30 minutes at a stirring rate of 120-180 rpm and room temperature to obtain loaded particles.

2. The method for preparing a viscoelastic polymer particle oil-displacing agent according to claim 1, characterized in that: In step A1, the ratio of 4-aminopiperidine, 1,5-dibromopentane and potassium carbonate is 0.04-0.05 mol: 0.042-0.052 mol: 0.8-1 g; the ratio of intermediate 1, 4-vinylbenzaldehyde and anhydrous ethanol is 0.04-0.045 mol: 0.042-0.048 mol: 80-100 mL.

3. The method for preparing a viscoelastic polymer particle oil-displacing agent according to claim 1, characterized in that: In step A2, the ratio of 6-methylisocytosine to ethyl isocyanate acrylate is 0.03-0.04 mol: 0.03-0.04 mol; the mass concentration of the ammonium persulfate solution is 0.1 g / mL, and the ratio of acrylamide, intermediate 2, intermediate 3 and ammonium persulfate solution is 0.04-0.05 mol: 0.02-0.022 mol: 0.01-0.012 mol: 24-26 mL.

4. The method for preparing a viscoelastic polymer particle oil-displacing agent according to claim 1, characterized in that: In step B1, the amount ratio of carboxylated silica microspheres, 4,4'-methylenebis(phenyl isocyanate), dibutyltin dilaurate and β-cyclodextrin is 2.8-3 g: 0.04-0.05 mol: 0.2-0.3 mL: 6-8 g.

5. The method for preparing a viscoelastic polymer particle oil-displacing agent according to claim 1, characterized in that: In step B2, the amount ratio of sodium montmorillonite, carboxymethyl chitosan and deionized water is 2-2.2g: 0.04-0.06g: 25-30mL; the mass fraction of glutaraldehyde solution is 25%, and the amount ratio of modified montmorillonite, glutaraldehyde solution and adamantane is 2-2.2g: 100-110mL: 0.6-0.8g.

6. The method for preparing a viscoelastic polymer particle oil-displacing agent according to claim 1, characterized in that: In step B3: the ratio of precursor, supported montmorillonite and deionizer is 0.7-0.8 g: 2.4-2.6 g: 30-35 mL.

7. A viscoelastic polymer particle oil-displacing agent, characterized in that: Prepared according to any one of claims 1 to 6.