Fracturing fluid containing modified benzyl trichloride and preparation method thereof

Abstract

The invention relates to the technical field of fracturing fluids, and discloses a fracturing fluid containing modified benzyl trichloride and a preparation method thereof. Modified polyacrylamide, a modified benzyl trichloride antibacterial agent, a sodium persulfate gel breaker and a zirconium oxychloride cross-linking agent are stirred and mixed in water to obtain the fracturing fluid containing modified benzyl trichloride. A benzene ring group improves the rigidity and stability of a chitosan molecular chain, piperidine is a nitrogen-containing six-membered heterocycle, can cause the change of the permeability of bacterial cell membranes, and plays an antibacterial role; a benzene ring and a piperidine ring are grafted on the chitosan, so that the high temperature resistance and the antibacterial property of the chitosan are improved. The polyhexamethylene biguanide is easily subjected to electrostatic adsorption with anion parts on the surfaces of bacterial cells, so that a bactericidal effect is achieved; quaternary phosphonium salt is grafted into polyacrylamide, so that the positive charge density is improved, the adsorption capacity to bacteria is enhanced, and the antibacterial effect is enhanced; a benzene ring and a triazinyl group are introduced into a polyacrylamide molecular chain, so that the high temperature resistance of polyacrylamide is improved.

Description

Technical Field

[0001] The invention relates to the technical field of fracturing fluid, in particular to a fracturing fluid containing modified tribenzyl chloride and a preparation method thereof. Background Art

[0002] Fracturing technology is the most important and effective means of shale reservoir development at home and abroad. Microorganisms are widely present in fracturing formations, and sulfate-reducing bacteria cause safety problems, environmental pollution and economic losses in oil extraction and transportation. Some polymers in oilfield chemistry cause equipment damage or corrosion, pipeline perforation, short circuit, leakage or other serious problems. This is because the polymers in the system are decomposed by anaerobic microorganisms. Therefore, how to effectively control and reduce the growth of microorganisms during fracturing is a key issue that needs to be solved urgently. As an important component of fracturing technology, fracturing fluid plays an important role in transmitting working pressure, supporting artificial fractures, and protecting oil and gas reservoirs. The polymer fracturing fluid system represented by polyacrylamide has the advantages of strong viscosity enhancement, low residue, low friction, easy gel breaking and little damage to the reservoir. It has been promoted and applied in major oil fields at home and abroad and has achieved good results. The fracturing fluid prepared in the document "New Ultra-High Temperature Fracturing Fluid System with Temperature Resistance of 230℃" has good temperature and shear resistance at 230℃, but its antibacterial effect needs to be improved. Summary of the invention

[0003] 1. Technical issues to be resolved In view of the shortcomings of the prior art, the present invention provides a fracturing fluid containing modified tribenzyl chloride and a preparation method thereof. The fracturing fluid prepared by the present invention has good antibacterial and high temperature resistance effects.

[0004] (II) Technical solution To achieve the above object, the present invention provides the following technical solution: a fracturing fluid containing modified tribenzyl chloride, comprising the following components by weight: 2-6 parts by weight of modified polyacrylamide, 0.4-0.8 parts by weight of modified tribenzyl chloride antibacterial agent, 0.02-0.06 parts by weight of sodium persulfate breaker, 0.03-0.09 parts by weight of zirconium oxychloride crosslinking agent, and 80-120 parts by weight of water.

[0005] Preferably, the preparation method of the modified tribenzyl chloride comprises the following steps: (1) Add benzyl chloride, 4-piperidinic acid, deionized water and triethylamine into a flask, stir and mix, then heat to 74-80°C and react for 2-3 hours. After the reaction is completed, cool to room temperature, add saturated brine and ethyl acetate for extraction, and dry by rotary evaporation to obtain intermediate 1; (2) Dissolve 5-8 g of chitosan in 30-40 mL of 1%-1.4% acetic acid solution, stir to dissolve, add 0.02-0.06 g of initiator and react for 30-50 min, then add 12-18 g of intermediate 1, pass nitrogen protection, heat to 80-90 °C and react for 12-18 h. After the reaction is completed, filter and freeze-dry to obtain a modified trichlorobenzyl antibacterial agent.

[0006] Preferably, in step (1), the molar ratio of benzyl chloride, 4-piperidinic acid, deionized water and triethylamine is 1:1.14-1.2:0.2-0.5:2.8-3.2.

[0007] Preferably, the initiator in step (2) is 1-hydroxybenzotriazole.

[0008] Preferably, the preparation method of the modified polyacrylamide comprises the following steps: S1. Add 3-9 g of cyanuric chloride to 50-80 mL of N,N-dimethylformamide solvent at 0-5°C, stir to dissolve, then add 6-17 g of polyhexamethylene biguanide solution dropwise thereto, then add 0.02-0.04 g of acid binding agent thereto to adjust the pH to neutral, react at constant temperature for 7-8 hours, and after the reaction is completed, wash and dry to obtain guanidinized cyanuric chloride; S2. Add 7-14 g of guanidinized cyanuric chloride to 45-60 mL of tetrahydrofuran solvent, stir to dissolve, heat to 37-45 ° C, add 9-17 g of allyl diphenylphosphine dropwise thereto, and after the addition is complete, react at a constant temperature for 6-10 h. After the reaction is completed, cool and distill under reduced pressure to obtain a guanidinized cyanuric chloride modified quaternary phosphonium salt; S3. Add 20-28 g of acrylamide, 12-15 g of methacrylic acid, 0.4-0.8 g of guanidinium cyanuric chloride-modified quaternary phosphonium salt, 0.2-0.6 g of 2-acrylamide-2-methylpropane sulfonic acid to 100-140 mL of deionized water, stir and mix, add sodium hydroxide solution to adjust the pH value to 7-8, pass nitrogen for 10-15 min to deoxygenate, add 0.04-0.08 g of initiator, heat to 45-60 ° C and react for 4-7 h. After the reaction, wash with anhydrous ethanol and dry in vacuo to obtain modified polyacrylamide.

[0009] Preferably, the acid binding agent in S1 is triethylamine.

[0010] Preferably, the initiator in S3 is azobisisobutylamidine hydrochloride.

[0011] Preferably, the preparation method of the fracturing fluid containing modified tribenzyl chloride is: adding modified polyacrylamide, modified tribenzyl chloride antibacterial agent, sodium persulfate gel breaker, zirconium oxychloride crosslinker into water, stirring and mixing at 500-700 rpm for 5-8 minutes to obtain the fracturing fluid containing modified tribenzyl chloride.

[0012] 3. Beneficial technical effects The invention obtains a fracturing fluid containing modified tribenzyl chloride by stirring and mixing modified polyacrylamide, modified tribenzyl chloride antibacterial agent, sodium persulfate gel breaker and zirconium oxychloride crosslinking agent in water.

[0013] In the modified trichlorobenzyl antibacterial agent, chitosan can be adsorbed on the surface of bacterial cells to form a polymer film layer, preventing the transport of nutrients into the cells. Furthermore, the positive charge of chitosan interacts with the negative charge on the surface of the cell membrane, which can change the permeability of the cell membrane and cause bacterial cell death. Chitosan can also selectively chelate metal ions that play a key role in microbial growth, inhibiting microbial growth, thereby playing an antibacterial role. The benzene ring group improves the rigidity and stability of the chitosan molecular chain, making it less likely to decompose or deform under high temperature conditions; piperidine is a nitrogen-containing six-membered heterocyclic ring that can interact with the phospholipid molecules in the bacterial cell membrane, causing changes in the permeability of the cell membrane, thereby affecting the normal function of the cell and playing an antibacterial role; by grafting the benzene ring rigid group and piperidine ring on the chitosan molecule, the high temperature resistance and antibacterial properties of the chitosan molecule are further improved. In modified polyacrylamide, polyhexamethylene biguanide, due to its high activity, makes the polymer positively charged, and it is easy to electrostatically adsorb to the anionic parts of the bacterial cell surface, causing the cell surface structure to denature or destroy, thereby playing a bactericidal role; the molecular structure of quaternary phosphonium salts contains phosphorus atoms, which have a large ionic radius and strong polarization effect, which makes it easier for quaternary phosphonium salts to adsorb bacteria with negative ions, and can more effectively destroy the bacterial cell wall and cell membrane, thereby causing bacterial death. The grafting of quaternary phosphonium salts into polyacrylamide increases the positive charge density and enhances the adsorption capacity of bacterial cells. At the same time, the binding force with the cytoplasmic membrane is enhanced, making it easier to destroy the bacteria, thereby enhancing the antibacterial effect; the high temperature resistance of polyacrylamide is improved by introducing benzene rings and triazine rigid structures into the polyacrylamide molecular chain. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is the synthetic reaction formula of modified trichlorobenzyl antibacterial agent. DETAILED DESCRIPTION Example 1

[0015] (1) Add benzyl chloride, 4-piperidinic acid, deionized water and triethylamine into a flask, wherein the molar ratio of benzyl chloride, 4-piperidinic acid, deionized water and triethylamine is 1:1.14:0.2:2.8, stir and mix, heat to 74°C and react for 2 hours. After the reaction is completed, cool to room temperature, add saturated brine and ethyl acetate for extraction, and dry by rotary evaporation to obtain intermediate 1; (2) Dissolve 5 g of chitosan in 30 mL of 1% acetic acid solution, stir to dissolve, add 0.02 g of 1-hydroxybenzotriazole initiator to react for 30 min, then add 12 g of intermediate 1, pass nitrogen protection, heat to 80 ° C to react for 12 h, filter and freeze-dry after the reaction to obtain a modified trichlorobenzyl antibacterial agent; (3) Add 3 g of cyanuric chloride to 50 mL of N,N-dimethylformamide solvent at 0°C, stir to dissolve, then drop 6 g of polyhexamethylene biguanide solution into it, then add 0.02 g of triethylamine acid binding agent to adjust the pH to neutral, and react at a constant temperature for 7 h. After the reaction is completed, wash and dry to obtain guanidinium cyanuric chloride; (4) Add 7 g of guanidinium cyanuric chloride to 45 mL of tetrahydrofuran solvent, stir to dissolve, heat to 37° C., dropwise add 9 g of allyl diphenylphosphine, and react at constant temperature for 6 h. After the reaction is completed, cool and distill under reduced pressure to obtain guanidinium cyanuric chloride modified quaternary phosphonium salt; (5) Add 20 g of acrylamide, 12 g of methacrylic acid, 0.4 g of guanidinium cyanuric chloride modified quaternary phosphonium salt, and 0.2 g of 2-acrylamide-2-methylpropanesulfonic acid to 100 mL of deionized water, stir and mix, add sodium hydroxide solution to adjust the pH value to 7, pass nitrogen for 10 min to deoxygenate, add 0.04 g of azobisisobutylamidine hydrochloride initiator, heat to 45 ° C and react for 4 h. After the reaction is completed, wash with anhydrous ethanol and vacuum dry to obtain modified polyacrylamide; (6) Add 2 parts by weight of modified polyacrylamide, 0.4 parts by weight of modified trichlorobenzyl antibacterial agent, 0.02 parts by weight of sodium persulfate gel breaker, and 0.03 parts by weight of zirconium oxychloride crosslinking agent to 80 parts by weight of water, and stir and mix at 500 rpm for 5 minutes to obtain a fracturing fluid containing modified trichlorobenzyl. Example 2

[0016] (1) Add benzyl chloride, 4-piperidinic acid, deionized water and triethylamine into a flask, wherein the molar ratio of benzyl chloride, 4-piperidinic acid, deionized water and triethylamine is 1:1.2:0.5:3.2, stir and mix, heat to 80°C and react for 3 hours. After the reaction is completed, cool to room temperature, add saturated brine and ethyl acetate for extraction, and dry by rotary evaporation to obtain intermediate 1; (2) 8 g of chitosan was dissolved in 40 mL of 1.4% acetic acid solution, stirred to dissolve, 0.06 g of 1-hydroxybenzotriazole initiator was added to react for 50 min, and then 18 g of intermediate 1 was added thereto, nitrogen was introduced for protection, the temperature was raised to 90 °C and the reaction was carried out for 18 h. After the reaction was completed, the mixture was filtered and freeze-dried to obtain a modified trichlorobenzyl antibacterial agent; (3) Add 9 g of cyanuric chloride to 80 mL of N,N-dimethylformamide solvent at 5°C, stir to dissolve, then drop 17 g of polyhexamethylene biguanide solution into it, then add 0.04 g of triethylamine acid binding agent to adjust the pH to neutral, and react at a constant temperature for 8 h. After the reaction is completed, wash and dry to obtain guanidinium cyanuric chloride; (4) Add 14 g of guanidinium cyanuric chloride to 60 mL of tetrahydrofuran solvent, stir to dissolve, heat to 45° C., dropwise add 17 g of allyl diphenylphosphine, and after the addition is complete, react at a constant temperature for 10 h. After the reaction is complete, cool, and distill under reduced pressure to obtain a quaternary phosphonium salt modified with guanidinium cyanuric chloride; (5) Add 28 g of acrylamide, 15 g of methacrylic acid, 0.8 g of guanidinium cyanuric chloride-modified quaternary phosphonium salt, and 0.6 g of 2-acrylamide-2-methylpropanesulfonic acid to 140 mL of deionized water, stir and mix, add sodium hydroxide solution to adjust the pH value to 8, pass nitrogen for 15 min to deoxygenate, add 0.08 g of azobisisobutylamidine hydrochloride initiator, heat to 60 ° C and react for 7 h. After the reaction is completed, wash with anhydrous ethanol and vacuum dry to obtain modified polyacrylamide; (6) Add 6 parts by weight of modified polyacrylamide, 0.8 parts by weight of modified trichlorobenzyl antibacterial agent, 0.06 parts by weight of sodium persulfate gel breaker, and 0.09 parts by weight of zirconium oxychloride crosslinking agent to 120 parts by weight of water, and stir and mix at 700 rpm for 8 minutes to obtain a fracturing fluid containing modified trichlorobenzyl. Example 3

[0017] (1) Add benzyl chloride, 4-piperidinic acid, deionized water and triethylamine into a flask, wherein the molar ratio of benzyl chloride, 4-piperidinic acid, deionized water and triethylamine is 1:1.17:0.35:3, stir and mix, heat to 77°C and react for 2.5 hours. After the reaction is completed, cool to room temperature, add saturated brine and ethyl acetate for extraction, and dry by rotary evaporation to obtain intermediate 1; (2) 6.5 g of chitosan was dissolved in 35 mL of 1.2% acetic acid solution, stirred to dissolve, 0.04 g of 1-hydroxybenzotriazole initiator was added to react for 40 min, and then 15 g of intermediate 1 was added thereto, nitrogen was introduced for protection, the temperature was raised to 85 °C and the reaction was carried out for 15 h. After the reaction was completed, the mixture was filtered and freeze-dried to obtain a modified trichlorobenzyl antibacterial agent; (3) Add 6 g of cyanuric chloride to 65 mL of N,N-dimethylformamide solvent at 2°C, stir to dissolve, then drop 11.5 g of polyhexamethylene biguanide solution, then add 0.03 g of triethylamine acid binding agent to adjust the pH to neutral, and react at a constant temperature for 7.5 h. After the reaction is completed, wash and dry to obtain guanidinium cyanuric chloride; (4) Add 10.5 g of guanidinium cyanuric chloride to 52 mL of tetrahydrofuran solvent, stir to dissolve, heat to 41° C., dropwise add 13 g of allyl diphenylphosphine, and react at a constant temperature for 8 h. After the reaction is complete, cool and distill under reduced pressure to obtain guanidinium cyanuric chloride modified quaternary phosphonium salt; (5) Add 24 g of acrylamide, 13.5 g of methacrylic acid, 0.6 g of guanidinium cyanuric chloride modified quaternary phosphonium salt, and 0.4 g of 2-acrylamide-2-methylpropanesulfonic acid to 120 mL of deionized water, stir and mix, add sodium hydroxide solution to adjust the pH value to 7.5, pass nitrogen for 12 min to deoxygenate, add 0.06 g of azobisisobutylamidine hydrochloride initiator, heat to 52 ° C and react for 5.5 h. After the reaction is completed, wash with anhydrous ethanol and vacuum dry to obtain modified polyacrylamide; (6) Add 4 parts by weight of modified polyacrylamide, 0.6 parts by weight of modified trichlorobenzyl antibacterial agent, 0.04 parts by weight of sodium persulfate gel breaker, and 0.06 parts by weight of zirconium oxychloride crosslinking agent to 100 parts by weight of water, and stir and mix at 600 rpm for 6 minutes to obtain a fracturing fluid containing modified trichlorobenzyl. Example 4

[0018] (1) Add benzyl chloride, 4-piperidinic acid, deionized water and triethylamine into a flask, wherein the molar ratio of benzyl chloride, 4-piperidinic acid, deionized water and triethylamine is 1:1.14:0.2:2.8, stir and mix, heat to 74°C and react for 2 hours. After the reaction is completed, cool to room temperature, add saturated brine and ethyl acetate for extraction, and dry by rotary evaporation to obtain intermediate 1; (2) Dissolve 5 g of chitosan in 30 mL of 1% acetic acid solution, stir to dissolve, add 0.02 g of 1-hydroxybenzotriazole initiator to react for 30 min, then add 12 g of intermediate 1, pass nitrogen protection, heat to 80 ° C to react for 12 h, filter and freeze-dry after the reaction to obtain a modified trichlorobenzyl antibacterial agent; (3) Add 9 g of cyanuric chloride to 80 mL of N,N-dimethylformamide solvent at 5°C, stir to dissolve, then drop 17 g of polyhexamethylene biguanide solution into it, then add 0.04 g of triethylamine acid binding agent to adjust the pH to neutral, and react at a constant temperature for 8 h. After the reaction is completed, wash and dry to obtain guanidinium cyanuric chloride; (4) Add 14 g of guanidinium cyanuric chloride to 60 mL of tetrahydrofuran solvent, stir to dissolve, heat to 45° C., dropwise add 17 g of allyl diphenylphosphine, and after the addition is complete, react at a constant temperature for 10 h. After the reaction is complete, cool, and distill under reduced pressure to obtain a quaternary phosphonium salt modified with guanidinium cyanuric chloride; (5) Add 24 g of acrylamide, 13.5 g of methacrylic acid, 0.6 g of guanidinium cyanuric chloride modified quaternary phosphonium salt, and 0.4 g of 2-acrylamide-2-methylpropanesulfonic acid to 120 mL of deionized water, stir and mix, add sodium hydroxide solution to adjust the pH value to 7.5, pass nitrogen for 12 min to deoxygenate, add 0.06 g of azobisisobutylamidine hydrochloride initiator, heat to 52 ° C and react for 5.5 h. After the reaction is completed, wash with anhydrous ethanol and vacuum dry to obtain modified polyacrylamide; (6) Add 4 parts by weight of modified polyacrylamide, 0.6 parts by weight of modified trichlorobenzyl antibacterial agent, 0.04 parts by weight of sodium persulfate gel breaker, and 0.06 parts by weight of zirconium oxychloride crosslinking agent to 100 parts by weight of water, and stir and mix at 600 rpm for 6 minutes to obtain a fracturing fluid containing modified trichlorobenzyl. Example 5

[0019] (1) Add benzyl chloride, 4-piperidinic acid, deionized water and triethylamine into a flask, wherein the molar ratio of benzyl chloride, 4-piperidinic acid, deionized water and triethylamine is 1:1.2:0.5:3.2, stir and mix, heat to 80°C and react for 3 hours. After the reaction is completed, cool to room temperature, add saturated brine and ethyl acetate for extraction, and dry by rotary evaporation to obtain intermediate 1; (2) 8 g of chitosan was dissolved in 40 mL of 1.4% acetic acid solution, stirred to dissolve, 0.06 g of 1-hydroxybenzotriazole initiator was added to react for 50 min, and then 18 g of intermediate 1 was added thereto, nitrogen was introduced for protection, the temperature was raised to 90 °C and the reaction was carried out for 18 h. After the reaction was completed, the mixture was filtered and freeze-dried to obtain a modified trichlorobenzyl antibacterial agent; (3) Add 6 g of cyanuric chloride to 65 mL of N,N-dimethylformamide solvent at 2°C, stir to dissolve, then drop 11.5 g of polyhexamethylene biguanide solution, then add 0.03 g of triethylamine acid binding agent to adjust the pH to neutral, and react at a constant temperature for 7.5 h. After the reaction is completed, wash and dry to obtain guanidinium cyanuric chloride; (4) Add 10.5 g of guanidinium cyanuric chloride to 52 mL of tetrahydrofuran solvent, stir to dissolve, heat to 41° C., dropwise add 13 g of allyl diphenylphosphine, and react at a constant temperature for 8 h. After the reaction is complete, cool and distill under reduced pressure to obtain guanidinium cyanuric chloride modified quaternary phosphonium salt; (5) Add 20 g of acrylamide, 12 g of methacrylic acid, 0.4 g of guanidinium cyanuric chloride modified quaternary phosphonium salt, and 0.2 g of 2-acrylamide-2-methylpropanesulfonic acid to 100 mL of deionized water, stir and mix, add sodium hydroxide solution to adjust the pH value to 7, pass nitrogen for 10 min to deoxygenate, add 0.04 g of azobisisobutylamidine hydrochloride initiator, heat to 45 ° C and react for 4 h. After the reaction is completed, wash with anhydrous ethanol and vacuum dry to obtain modified polyacrylamide; (6) Add 2 parts by weight of modified polyacrylamide, 0.4 parts by weight of modified trichlorobenzyl antibacterial agent, 0.02 parts by weight of sodium persulfate gel breaker, and 0.03 parts by weight of zirconium oxychloride crosslinking agent to 80 parts by weight of water, and stir and mix at 500 rpm for 5 minutes to obtain a fracturing fluid containing modified trichlorobenzyl.

[0020] Comparative Example 1 The difference between this comparative example and Example 5 is that step (5) does not contain guanidinated cyanuric chloride-modified quaternary phosphonium salt.

[0021] Comparative Example 2 The difference between this comparative example and Example 5 is that step (6) does not contain modified trichlorobenzyl antibacterial agent.

[0022] The apparent viscosity of the fracturing fluids in Examples 1-5 and Comparative Examples 1-2 at different temperatures was tested using a rheometer. The shear rate was 100 s -1 The shearing time was 120 min. The results are shown in Table 1.

[0023] Table 1: High temperature resistance test.

[0024]

[0025] It can be seen from Table 1 that the fracturing fluids in Examples 1-5 of the present invention can still maintain a higher apparent viscosity at high temperatures than the fracturing fluids in Comparative Examples 1-2, and have better high temperature resistance.

[0026] Referring to SY / T0532-1993 "Oilfield Injection Water Bacteria Analysis Method - Extinction Dilution Method", the antibacterial performance of the fracturing fluids in Examples 1-5 and Comparative Examples 1-2 was tested and the antibacterial rate was calculated. The results are shown in Table 2.

[0027] Table 2: Antibacterial performance test.

[0028] project Antibacterial rate (%) Example 1 99.6 Example 2 99.4 Example 3 99.2 Example 4 98.8 Example 5 99.0 Comparative Example 1 92.4 Comparative Example 2 91.5 It can be seen from Table 2 that the fracturing fluids in Examples 1-5 of the present invention have better antibacterial effects than the fracturing fluids in Comparative Examples 1-2.

[0029] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A fracturing fluid containing modified benzyl trichloride, characterized in that: The invention comprises the following components by weight: 2-6 parts by weight of modified polyacrylamide, 0.4-0.8 parts by weight of modified trichlorobenzyl antibacterial agent, 0.02-0.06 parts by weight of sodium persulfate gel breaker, 0.03-0.09 parts by weight of zirconium oxychloride crosslinking agent and 80-120 parts by weight of water.

2. The fracturing fluid containing modified benzyl trichloride according to claim 1, characterized in that: The preparation method of the modified tribenzyl chloride comprises the following steps: (1) Add benzyl chloride, 4-piperidinic acid, deionized water and triethylamine into a flask, stir and mix, then heat to 74-80°C and react for 2-3 hours. After the reaction is completed, cool to room temperature, add saturated brine and ethyl acetate for extraction, and dry by rotary evaporation to obtain intermediate 1; (2) Dissolve 5-8 g of chitosan in 30-40 mL of 1%-1.4% acetic acid solution, stir to dissolve, add 0.02-0.06 g of initiator and react for 30-50 min, then add 12-18 g of intermediate 1, pass nitrogen protection, heat to 80-90 °C and react for 12-18 h. After the reaction is completed, filter and freeze-dry to obtain a modified trichlorobenzyl antibacterial agent.

3. The fracturing fluid containing modified benzyl trichloride according to claim 2, characterized in that: In the step (1), the molar ratio of benzyl chloride, 4-piperidinic acid, deionized water and triethylamine is 1:1.14-1.2:0.2-0.5:2.8-3.

2.

4. The fracturing fluid containing modified benzyl trichloride according to claim 2, characterized in that: The initiator in step (2) is 1-hydroxybenzotriazole.

5. The fracturing fluid containing modified benzyl trichloride according to claim 1, characterized in that: The preparation method of the modified polyacrylamide comprises the following steps: S1. Add 3-9 g of cyanuric chloride to 50-80 mL of N,N-dimethylformamide solvent at 0-5°C, stir to dissolve, then add 6-17 g of polyhexamethylene biguanide solution dropwise thereto, then add 0.02-0.04 g of acid binding agent thereto to adjust the pH to neutral, react at constant temperature for 7-8 hours, and after the reaction is completed, wash and dry to obtain guanidinized cyanuric chloride; S2. Add 7-14 g of guanidinized cyanuric chloride to 45-60 mL of tetrahydrofuran solvent, stir to dissolve, heat to 37-45 ° C, add 9-17 g of allyl diphenylphosphine dropwise thereto, and after the addition is complete, react at a constant temperature for 6-10 h. After the reaction is completed, cool and distill under reduced pressure to obtain a guanidinized cyanuric chloride modified quaternary phosphonium salt; S3. Add 20-28 g of acrylamide, 12-15 g of methacrylic acid, 0.4-0.8 g of guanidinium cyanuric chloride-modified quaternary phosphonium salt, 0.2-0.6 g of 2-acrylamide-2-methylpropane sulfonic acid to 100-140 mL of deionized water, stir and mix, add sodium hydroxide solution to adjust the pH value to 7-8, pass nitrogen for 10-15 min to deoxygenate, add 0.04-0.08 g of initiator, heat to 45-60 ° C and react for 4-7 h. After the reaction, wash with anhydrous ethanol and dry in vacuo to obtain modified polyacrylamide.

6. The fracturing fluid containing modified benzyl trichloride according to claim 5, characterized in that: The acid binding agent in S1 is triethylamine.

7. The fracturing fluid containing modified benzyl trichloride according to claim 5, characterized in that: The initiator in S3 is azobisisobutylamidine hydrochloride.

8. A method for preparing a fracturing fluid containing modified benzyl trichloride according to any one of claims 1 to 7, characterized in that: The preparation method of the fracturing fluid containing modified tribenzyl chloride is as follows: adding modified polyacrylamide, modified tribenzyl chloride antibacterial agent, sodium persulfate gel breaker and zirconium oxychloride crosslinker into water, stirring and mixing at 500-700 rpm for 5-8 minutes to obtain the fracturing fluid containing modified tribenzyl chloride.

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