A kind of bactericidal corrosion inhibitor and scale inhibitor for oil and gas fields and preparation method thereof

Abstract

The invention relates to the technical field of scale inhibitors, and in particular to a bactericidal, corrosion-inhibiting and scale inhibitor for oil and gas fields and a preparation method thereof. The bactericidal, corrosion-inhibiting and scale inhibitor comprises the following raw materials in parts by weight: 15-18 parts of loaded microspheres, 8-10 parts of reinforcing aids and 60-70 parts of deionized water; by adding the loaded microspheres and the reinforcing aids, a host-guest inclusion complex between the two is formed to form a nano valve structure, which realizes a controlled release function under temperature and pH stimulation, thereby achieving long-term good bactericidal, corrosion-inhibiting and scale inhibition performance, and solves the problem that the existing corrosion-inhibiting and scale inhibitors cannot penetrate into oil fields, resulting in a decrease in their performance of bactericidal, corrosion-inhibiting and scale inhibition.

Description

Technical Field

[0001] The invention relates to the technical field of scale inhibitors, and in particular to a bactericidal, corrosion-inhibiting and scale inhibitor for oil and gas fields and a preparation method thereof. Background Art

[0002] In order to improve the crude oil recovery rate of oil and gas fields, water injection is used in oil and gas fields, which causes dissolved oxygen to flow into the injection wells. Foam flooding technology introduces oxygen into the pipeline, causing oxygen corrosion of the downhole pipeline and even severe corrosion perforation. At the same time, due to the large amount of scaling ions and various bacteria in the water injection process, it is very easy to affect the production of oil and gas fields, resulting in a decrease in the recovery rate of oil and gas fields. Although the commonly used corrosion and scale inhibitors on the market have good bactericidal, corrosion and scale inhibition properties, due to their own characteristics, they cannot penetrate deep into the oil fields with higher temperatures, which affects their actual use effect. Summary of the invention

[0003] The purpose of the present invention is to provide a bactericidal, corrosion-inhibiting and scale inhibitor for oil and gas fields and a preparation method thereof. By adding loaded microspheres and reinforcing additives, a host-guest inclusion complex between the two is formed to form a nano-valve structure, which realizes a controlled release function under temperature and pH stimulation, thereby achieving long-term good bactericidal, corrosion-inhibiting and scale inhibition performance, solving the problem that existing corrosion-inhibiting and scale inhibitors cannot penetrate into oil fields, resulting in a decrease in their performance in bactericidal, corrosion-inhibiting and scale inhibition.

[0004] The purpose of the present invention can be achieved by the following technical scheme: a method for preparing a bactericidal, corrosion-inhibiting and scale inhibitor for oil and gas fields, comprising the following steps: weighing the following raw materials by weight: 15-18 parts of loaded microspheres, 8-10 parts of reinforcing aids and 60-70 parts of deionized water; mixing the loaded microspheres, reinforcing aids and deionized water, stirring at a stirring rate of 600 rpm and a temperature of 35° C. for 24 hours to obtain a bactericidal, corrosion-inhibiting and scale inhibitor for oil and gas fields;

[0005] The loaded microspheres are prepared by the following steps:

[0006] Step A1: Mix nano-silicon dioxide and deionized water and ultrasonically disperse for 15-20 minutes, stir and add to a mixed system of anhydrous sodium acetate, lanthanum acetate and deionized water, ultrasonically disperse for 10 minutes, and react for 12 hours at a stirring rate of 120-140 rpm and a temperature of 180° C. to obtain hybrid microspheres;

[0007] The dosage ratio of nano silicon dioxide, anhydrous sodium acetate and lanthanum acetate is 0.3-0.35g: 2.8-3.1g: 2.1-2.4g;

[0008] During the reaction, lanthanum was doped into nano-silica by a hydrothermal method using nano-silica as a template and lanthanum acetate as a lanthanum source to form a hollow pore structure and prepare hybrid microspheres.

[0009] Step A2: chitosan and acetic acid solution were mixed, stirred at a stirring rate of 150-180 rpm at room temperature for 20 minutes, and then hybrid microspheres were added, and stirring was continued for 30 minutes, and then benzimidazole-2-carboxaldehyde and glutaraldehyde solution were added, and the temperature was raised to 35° C. and reacted for 3-4 hours to obtain modified microspheres;

[0010] The mass fraction of the acetic acid solution is 1%, the mass fraction of the glutaraldehyde solution is 10%, and the dosage ratio of chitosan, acetic acid solution, hybrid microspheres, benzimidazole-2-carboxaldehyde and glutaraldehyde solution is 1.2-1.5g:140-150mL:0.2-0.3g:0.008-0.009mol:3-4mL;

[0011] During the reaction, since the hybrid microspheres are based on nano-silica and doped with lanthanum, the surface of the hybrid microspheres contains a large number of active hydroxyl groups, which can form hydrogen bonds with chitosan. Then, benzimidazole-2-carboxaldehyde and glutaraldehyde solutions are added, and the aldehyde groups react with the amino groups in chitosan to form a Schiff base structure, and the chitosan is fixed, thereby forming a shell structure on the surface of the modified microspheres to obtain modified microspheres.

[0012] Step A3: Mix the modified microspheres and deionized water, stir and add sodium molybdate dihydrate, imidazoline and ethanol under the conditions of pressure of 0.08 MPa, stirring rate of 80-120 rpm and temperature of 40° C., and stir for 4-5 hours to obtain loaded microspheres;

[0013] The dosage ratio of modified microspheres, sodium molybdate dihydrate and imidazoline is 0.25-0.3g:1.5-1.8g:1.8-1.9g;

[0014] During the reaction, imidazoline is loaded onto the modified microspheres by a vacuum loading method, and simultaneously, due to the adsorption of molybdate anions by the modified microspheres, the molybdate anions are loaded onto the modified microspheres to obtain loaded microspheres;

[0015] The reinforcing aid is prepared by the following steps:

[0016] Step B1: β-cyclodextrin, pyridine and chloroform are stirred at a stirring rate of 140-180 rpm and a temperature of 60°C, and chloroacetyl chloride is added, and the reaction is carried out for 24 hours to obtain intermediate a. Intermediate a is mixed with N,N-dimethylformamide, and sodium azide is added at a stirring rate of 60-100 rpm and a temperature of 80°C, and the reaction is carried out for 10-12 hours to obtain intermediate b;

[0017] The dosage ratio of β-cyclodextrin, pyridine, chloroform and chloroacetyl chloride is 2.2-2.5 g: 25 mL: 25 mL: 8-9 mL; the dosage ratio of intermediate a, N, N-dimethylformamide and sodium azide is 1.8-1.9 g: 50-55 mL: 1-1.1 g;

[0018] During the reaction, the hydroxyl group in β-cyclodextrin first reacts with the acyl chloride structure in chloroacetyl chloride to introduce chlorine to obtain intermediate a. Then, under the action of sodium azide, the chlorine in intermediate a is azidized to an azide group to obtain intermediate b.

[0019] Step B2: Mix intermediate b, methyl propiolate and dimethyl sulfoxide, stir at a rate of 80-100 rpm and a temperature of 75°C, add cuprous iodide, and react for 24 hours to obtain intermediate c; mix intermediate c, ethanol and hydrochloric acid solution, stir at a rate of 80-100 rpm and a temperature of 80°C, add thiosemicarbazide, and react for 24 hours to obtain a reinforcing agent;

[0020] The ratio of intermediate b, methyl propiolate and cuprous iodide is 2.1-2.2 g: 1.5-1.6 mL: 0.12-0.14 g; the mass fraction of hydrochloric acid solution is 35%, and the ratio of intermediate c, hydrochloric acid solution and thiosemicarbazide is 1.6-1.7 g: 1.2-1.5 mL: 0.05-0.07 mol;

[0021] During the reaction, under the action of cuprous iodide as a catalyst, the azide group in intermediate b reacts with the acetylene group in methyl propiolate to form a triazole structure to obtain intermediate c. The ester group in intermediate c then reacts with the amino group in thiosemicarbazide to introduce a thiosemicarbazide structure to obtain a reinforcing agent.

[0022] Beneficial effects of the invention: The invention discloses a bactericidal, corrosion-inhibiting and scale-inhibiting agent for oil and gas fields and a preparation method thereof. By adding loaded microspheres and an enhancing agent, a host-guest inclusion complex between the two is formed to form a nano valve structure, which realizes a controlled release function under temperature and pH stimulation, thereby achieving long-term good bactericidal, corrosion-inhibiting and scale-inhibiting performance, and solves the problem that the existing corrosion-inhibiting and scale-inhibiting agents cannot penetrate into oil fields, resulting in a decrease in their performance of bactericidal, corrosion-inhibiting and scale-inhibiting; due to the host-guest inclusion complex between the loaded microspheres and the enhancing agent by the benzimidazole group and the β-cyclodextrin structure, a nano valve structure is formed, and in the bactericidal, corrosion-inhibiting and scale-inhibiting agent During the process of going deep into the oil field, due to the changes in temperature and pH, the valve opens, thus forming a controlled release effect to exert a long-term bactericidal, corrosion-inhibiting and scale-inhibiting effect. Since the loaded microspheres themselves are lanthanum-hybridized silica structures, they can effectively react with molybdic acid, imidazoline and reinforcing additives to form a compound to play a corrosion-inhibiting and scale-inhibiting effect. Moreover, since the reinforcing additive itself is mainly composed of β-cyclodextrin structure and has thiourea groups grafted with triazole structure, it can also play a good bactericidal, corrosion-inhibiting and scale-inhibiting effect when the valve is not opened, thereby ensuring that it can still exert its good bactericidal, corrosion-inhibiting and scale-inhibiting performance in different temperature ranges of the pipeline. 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 bactericidal, corrosion-inhibiting and scale inhibitor for oil and gas fields comprises the following steps: weighing the following raw materials in parts by weight: 15 parts of loaded microspheres, 8 parts of reinforcing aids and 60 parts of deionized water; mixing the loaded microspheres, reinforcing aids and deionized water, stirring at a stirring rate of 600 rpm and a temperature of 35° C. for 24 hours to prepare a bactericidal, corrosion-inhibiting and scale inhibitor for oil and gas fields;

[0025] The loaded microspheres are prepared by the following steps:

[0026] Step A1: commercially available Bisley nano-silica and deionized water were mixed and ultrasonically dispersed for 15 minutes, stirred and added to a mixed system of anhydrous sodium acetate, lanthanum acetate and deionized water, ultrasonically dispersed for 10 minutes, and reacted for 12 hours at a stirring rate of 120 rpm and a temperature of 180° C. to obtain hybrid microspheres;

[0027] The dosage ratio of nano-silicon dioxide, anhydrous sodium acetate and lanthanum acetate is 0.3g:2.8g:2.1g;

[0028] Step A2: Mix the commercially available Huanxu chitosan and acetic acid solution, stir at a stirring rate of 150 rpm at room temperature for 20 min, then add the hybrid microspheres, continue stirring for 30 min, then add benzimidazole-2-carboxaldehyde and glutaraldehyde solution, heat to 35°C, react for 3 h, and obtain modified microspheres;

[0029] The mass fraction of acetic acid solution is 1%, the mass fraction of glutaraldehyde solution is 10%, and the dosage ratio of chitosan, acetic acid solution, hybrid microspheres, benzimidazole-2-carboxaldehyde and glutaraldehyde solution is 1.2g:140mL:0.2g:0.008mol:3mL;

[0030] Step A3: the modified microspheres and deionized water were mixed, and sodium molybdate dihydrate, imidazoline and ethanol were added under the conditions of a pressure of 0.08 MPa, a stirring rate of 80 rpm and a temperature of 40° C., and the mixture was stirred for 4 h to obtain loaded microspheres;

[0031] The dosage ratio of modified microspheres, sodium molybdate dihydrate and imidazoline is 0.25g:1.5g:1.8g;

[0032] The reinforcing aid is prepared by the following steps:

[0033] Step B1: β-cyclodextrin, pyridine and chloroform are stirred at a stirring rate of 140 rpm and a temperature of 60°C, and chloroacetyl chloride is added, and the reaction is carried out for 24 hours to obtain intermediate a. Intermediate a is mixed with N,N-dimethylformamide, and sodium azide is added at a stirring rate of 60 rpm and a temperature of 80°C, and the reaction is carried out for 10 hours to obtain intermediate b;

[0034] The dosage ratio of β-cyclodextrin, pyridine, chloroform and chloroacetyl chloride is 2.2g:25mL:25mL:8mL; the dosage ratio of intermediate a, N,N-dimethylformamide and sodium azide is 1.8g:50mL:1g;

[0035] Step B2: Mix intermediate b, methyl propiolate and dimethyl sulfoxide, stir at a stirring rate of 80 rpm and a temperature of 75°C, add cuprous iodide, and react for 24 hours to obtain intermediate c; mix intermediate c, ethanol and hydrochloric acid solution, stir at a stirring rate of 80 rpm and a temperature of 80°C, add thiosemicarbazide, and react for 24 hours to obtain a reinforcing agent;

[0036] The amount ratio of intermediate b, methyl propiolate and cuprous iodide is 2.1 g: 1.5 mL: 0.12 g; the mass fraction of hydrochloric acid solution is 35%, and the amount ratio of intermediate c, hydrochloric acid solution and thiosemicarbazide is 1.6 g: 1.2 mL: 0.05 mol.

[0037] Example 2 A method for preparing a bactericidal, corrosion-inhibiting and scale inhibitor for oil and gas fields comprises the following steps: weighing the following raw materials in parts by weight: 18 parts of loaded microspheres, 8 parts of reinforcing aids and 70 parts of deionized water; mixing the loaded microspheres, reinforcing aids and deionized water, stirring at a stirring rate of 600 rpm and a temperature of 35° C. for 24 hours to obtain a bactericidal, corrosion-inhibiting and scale inhibitor for oil and gas fields;

[0038] The loaded microspheres are prepared by the following steps:

[0039] Step A1: commercially available Bisley nano-silica and deionized water were mixed and ultrasonically dispersed for 15 minutes, stirred and added to a mixed system of anhydrous sodium acetate, lanthanum acetate and deionized water, ultrasonically dispersed for 10 minutes, and reacted for 12 hours at a stirring rate of 120 rpm and a temperature of 180° C. to obtain hybrid microspheres;

[0040] The dosage ratio of nano-silicon dioxide, anhydrous sodium acetate and lanthanum acetate is 0.3g:3.1g:2.4g;

[0041] Step A2: Mix commercially available Huanxu chitosan and acetic acid solution, stir at a stirring rate of 150 rpm, at room temperature for 20 min, then add hybrid microspheres, continue stirring for 30 min, then add benzimidazole-2-carboxaldehyde and glutaraldehyde solution, heat to 35°C, react for 4 h, and obtain modified microspheres;

[0042] The mass fraction of acetic acid solution is 1%, the mass fraction of glutaraldehyde solution is 10%, and the dosage ratio of chitosan, acetic acid solution, hybrid microspheres, benzimidazole-2-carboxaldehyde and glutaraldehyde solution is 1.2g:140mL:0.3g:0.009mol:3mL;

[0043] Step A3: the modified microspheres and deionized water were mixed, and sodium molybdate dihydrate, imidazoline and ethanol were added under the conditions of a pressure of 0.08 MPa, a stirring rate of 120 rpm and a temperature of 40° C., and the mixture was stirred for 4 h to obtain loaded microspheres;

[0044] The dosage ratio of modified microspheres, sodium molybdate dihydrate and imidazoline is 0.3g:1.5g:1.9g;

[0045] The reinforcing aid is prepared by the following steps:

[0046] Step B1: β-cyclodextrin, pyridine and chloroform are stirred at a stirring rate of 140 rpm and a temperature of 60°C, and chloroacetyl chloride is added, and the reaction is carried out for 24 hours to obtain intermediate a. Intermediate a is mixed with N,N-dimethylformamide, and sodium azide is added at a stirring rate of 100 rpm and a temperature of 80°C, and the reaction is carried out for 10 hours to obtain intermediate b;

[0047] The dosage ratio of β-cyclodextrin, pyridine, chloroform and chloroacetyl chloride is 2.5 g: 25 mL: 25 mL: 8 mL; the dosage ratio of intermediate a, N, N-dimethylformamide and sodium azide is 1.9 g: 50 mL: 1.1 g;

[0048] Step B2: Mix intermediate b, methyl propiolate and dimethyl sulfoxide, stir at a stirring rate of 100 rpm and a temperature of 75°C, add cuprous iodide, and react for 24 hours to obtain intermediate c; mix intermediate c, ethanol and hydrochloric acid solution, stir at a stirring rate of 80 rpm and a temperature of 80°C, add thiosemicarbazide, and react for 24 hours to obtain a reinforcing agent;

[0049] The amount ratio of intermediate b, methyl propiolate and cuprous iodide is 2.2 g:1.5 mL:0.14 g; the mass fraction of hydrochloric acid solution is 35%, and the amount ratio of intermediate c, hydrochloric acid solution and thiosemicarbazide is 1.6 g:1.2 mL:0.07 mol.

[0050] Example 3 A method for preparing a bactericidal, corrosion-inhibiting and scale inhibitor for oil and gas fields, comprising the following steps: weighing the following raw materials by weight: 18 parts of loaded microspheres, 10 parts of reinforcing aids and 70 parts of deionized water; mixing the loaded microspheres, reinforcing aids and deionized water, stirring at a stirring rate of 600 rpm and a temperature of 35° C. for 24 hours to prepare a bactericidal, corrosion-inhibiting and scale inhibitor for oil and gas fields;

[0051] The loaded microspheres are prepared by the following steps:

[0052] Step A1: commercially available Bisley nano-silica and deionized water were mixed and ultrasonically dispersed for 15 minutes, stirred and added to a mixed system of anhydrous sodium acetate, lanthanum acetate and deionized water, ultrasonically dispersed for 10 minutes, and reacted for 12 hours at a stirring rate of 120 rpm and a temperature of 180° C. to obtain hybrid microspheres;

[0053] The dosage ratio of nano-silicon dioxide, anhydrous sodium acetate and lanthanum acetate is 0.3g:2.8g:2.1g;

[0054] Step A2: Mix the commercially available Huanxu chitosan and acetic acid solution, stir at a stirring rate of 150 rpm at room temperature for 20 min, then add the hybrid microspheres, continue stirring for 30 min, then add benzimidazole-2-carboxaldehyde and glutaraldehyde solution, heat to 35°C, react for 3 h, and obtain modified microspheres;

[0055] The mass fraction of acetic acid solution is 1%, the mass fraction of glutaraldehyde solution is 10%, and the dosage ratio of chitosan, acetic acid solution, hybrid microspheres, benzimidazole-2-carboxaldehyde and glutaraldehyde solution is 1.2g:140mL:0.3g:0.008mol:3mL;

[0056] Step A3: the modified microspheres and deionized water were mixed, and sodium molybdate dihydrate, imidazoline and ethanol were added under the conditions of a pressure of 0.08 MPa, a stirring rate of 120 rpm and a temperature of 40° C., and the mixture was stirred for 5 h to obtain loaded microspheres;

[0057] The dosage ratio of modified microspheres, sodium molybdate dihydrate and imidazoline is 0.3g:1.8g:1.9g;

[0058] The reinforcing aid is prepared by the following steps:

[0059] Step B1: β-cyclodextrin, pyridine and chloroform were stirred at a stirring rate of 180 rpm and a temperature of 60°C, and chloroacetyl chloride was added, and the reaction was carried out for 24 hours to obtain intermediate a. Intermediate a was mixed with N,N-dimethylformamide, and sodium azide was added at a stirring rate of 100 rpm and a temperature of 80°C, and the reaction was carried out for 12 hours to obtain intermediate b;

[0060] The dosage ratio of β-cyclodextrin, pyridine, chloroform and chloroacetyl chloride is 2.5 g: 25 mL: 25 mL: 9 mL; the dosage ratio of intermediate a, N, N-dimethylformamide and sodium azide is 1.9 g: 55 mL: 1.1 g;

[0061] Step B2: Mix intermediate b, methyl propiolate and dimethyl sulfoxide, stir at a stirring rate of 100 rpm and a temperature of 75°C, add cuprous iodide, and react for 24 hours to obtain intermediate c; mix intermediate c, ethanol and hydrochloric acid solution, stir at a stirring rate of 100 rpm and a temperature of 80°C, add thiosemicarbazide, and react for 24 hours to obtain a reinforcing agent;

[0062] The amount ratio of intermediate b, methyl propiolate and cuprous iodide is 2.2 g: 1.6 mL: 0.14 g; the mass fraction of hydrochloric acid solution is 35%, and the amount ratio of intermediate c, hydrochloric acid solution and thiosemicarbazide is 1.7 g: 1.5 mL: 0.07 mol.

[0063] Comparative Example 1 Compared with Example 3, this comparative example replaces the enhancing auxiliary agent in the preparation process of a bactericidal, corrosion and scale inhibitor for oil and gas fields in Example 3 with a mixture of β-cyclodextrin and benzotriazole, wherein the mass ratio of β-cyclodextrin to benzotriazole is 1.6g:0.3g, and the other steps are the same.

[0064] Comparative Example 2 Compared with Example 3, this comparative example is different in that the hybrid microspheres in the preparation process of the loaded microspheres in Example 3 are replaced with commercially available Bisley nano-silica, and the other steps are the same.

[0065] Take the bactericidal corrosion inhibitor for oil and gas fields prepared in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2, 11.5g calcium chloride, 65.5g sodium chloride, 0.95g magnesium chloride, 0.12g sodium bicarbonate, 1000mL deionized water and 5mL of bacterial solution taken from the oil field and enriched are mixed to obtain simulated oil layer water, 2.5mL of bactericidal corrosion inhibitor is added, and the bacterial content is measured by the extinction dilution method at a temperature of 40°C, and the bactericidal rate is calculated. With reference to SY / T5273-2000 and SYT5673-1993, the corrosion hanging plate method is used to measure the corrosion rate at temperatures of 40°C and 60°C and pH values ​​of 5 and 7, respectively, to determine its corrosion inhibition performance, and the static scale inhibition method is used to calculate its relative scale inhibition rate to determine its scale inhibition performance. The steel plate used is N80 steel, and the reference test results are as follows:

[0066]

[0067] 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 and Comparative Example 2, as the temperature increases and the pH decreases, the valve in the bactericidal, corrosion and scale inhibitor opens, so that it can still maintain good corrosion and scale inhibition effects under high temperature and acidic conditions. In Comparative Example 1, the reinforcing auxiliary agent in the preparation process of a bactericidal, corrosion and scale inhibitor for oil and gas fields in Example 3 is replaced by a mixture of β-cyclodextrin and benzotriazole. Since a valve structure cannot be formed, its performance is reduced. In Comparative Example 2, the hybrid microspheres in the preparation process of the loaded microspheres in Example 3 are replaced by nano-silica. Due to the lack of a doping structure, its performance is reduced.

[0068] 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.

[0069] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a bactericidal, corrosion-inhibiting and scale-inhibiting agent for oil and gas fields, characterized in that: The method comprises the following steps: weighing the following raw materials in parts by weight: 15-18 parts of loaded microspheres, 8-10 parts of reinforcing aids and 60-70 parts of deionized water; mixing the loaded microspheres, reinforcing aids and deionized water, stirring at a stirring rate of 600 rpm and a temperature of 35° C. for 24 hours to prepare a bactericidal, corrosion-inhibiting and scale-inhibiting agent for oil and gas fields; The loaded microspheres are prepared by the following steps: Step A1: Mix nano-silicon dioxide and deionized water and ultrasonically disperse for 15-20 minutes, stir and add to a mixed system of anhydrous sodium acetate, lanthanum acetate and deionized water, ultrasonically disperse for 10 minutes, and react for 12 hours at a stirring rate of 120-140 rpm and a temperature of 180° C. to obtain hybrid microspheres; Step A2: chitosan and acetic acid solution were mixed, stirred at a stirring rate of 150-180 rpm at room temperature for 20 minutes, and then hybrid microspheres were added, and stirring was continued for 30 minutes, and then benzimidazole-2-carboxaldehyde and glutaraldehyde solution were added, and the temperature was raised to 35° C. and reacted for 3-4 hours to obtain modified microspheres; Step A3: Mix the modified microspheres and deionized water, stir and add sodium molybdate dihydrate, imidazoline and ethanol under the conditions of pressure of 0.08 MPa, stirring rate of 80-120 rpm and temperature of 40° C., and stir for 4-5 hours to obtain loaded microspheres; The reinforcing aid is prepared by the following steps: Step B1: β-cyclodextrin, pyridine and chloroform are stirred at a stirring rate of 140-180 rpm and a temperature of 60°C, and chloroacetyl chloride is added, and the reaction is carried out for 24 hours to obtain intermediate a. Intermediate a is mixed with N,N-dimethylformamide, and sodium azide is added at a stirring rate of 60-100 rpm and a temperature of 80°C, and the reaction is carried out for 10-12 hours to obtain intermediate b; Step B2: Mix intermediate b, methyl propiolate and dimethyl sulfoxide, stir and add cuprous iodide at a stirring rate of 80-100 rpm and a temperature of 75°C, and react for 24 hours to obtain intermediate c; mix intermediate c, ethanol and hydrochloric acid solution, stir and add thiosemicarbazide at a stirring rate of 80-100 rpm and a temperature of 80°C, and react for 24 hours to obtain a reinforcing agent.

2. The method for preparing a bactericidal, corrosion-inhibiting and scale-inhibiting agent for oil and gas fields according to claim 1, characterized in that: In step A1, the usage ratio of nano-silicon dioxide, anhydrous sodium acetate and lanthanum acetate is 0.3-0.35 g: 2.8-3.1 g: 2.1-2.4 g.

3. The method for preparing a bactericidal, corrosion-inhibiting and scale-inhibiting agent for oil and gas fields according to claim 1, characterized in that: In step A2: the mass fraction of the acetic acid solution is 1%, the mass fraction of the glutaraldehyde solution is 10%, and the amount ratio of chitosan, acetic acid solution, hybrid microspheres, benzimidazole-2-carboxaldehyde and glutaraldehyde solution is 1.2-1.5g:140-150mL:0.2-0.3g:0.008-0.009mol:3-4mL.

4. The method for preparing a bactericidal, corrosion-inhibiting and scale-inhibiting agent for oil and gas fields according to claim 1, characterized in that: In step A3: the usage ratio of modified microspheres, sodium molybdate dihydrate and imidazoline is 0.25-0.3 g:1.5-1.8 g:1.8-1.9 g.

5. The method for preparing a bactericidal, corrosion-inhibiting and scale-inhibiting agent for oil and gas fields according to claim 1, characterized in that: In step B1: the usage ratio of β-cyclodextrin, pyridine, chloroform and chloroacetyl chloride is 2.2-2.5 g: 25 mL: 25 mL: 8-9 mL; the usage ratio of intermediate a, N,N-dimethylformamide and sodium azide is 1.8-1.9 g: 50-55 mL: 1-1.1 g.

6. The method for preparing a bactericidal, corrosion-inhibiting and scale-inhibiting agent for oil and gas fields according to claim 1, characterized in that: In step B2, the ratio of intermediate b, methyl propiolate and cuprous iodide is 2.1-2.2 g: 1.5-1.6 mL: 0.12-0.14 g; the mass fraction of the hydrochloric acid solution is 35%, and the ratio of intermediate c, hydrochloric acid solution and thiosemicarbazide is 1.6-1.7 g: 1.2-1.5 mL: 0.05-0.07 mol.

7. A bactericidal, corrosion-inhibiting and scale-inhibiting agent for oil and gas fields, characterized in that: Prepared according to any one of claims 1 to 6.

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