Polyurethane-containing fracturing fluid and preparation method thereof

Abstract

The invention relates to the technical field of fracturing fluids, and discloses a polyurethane-containing fracturing fluid and a preparation method thereof.The preparation method comprises the steps that hexadecyl trimethyl ammonium chloride, polyurethane, sodium formate, sodium sulfonate modified benzoxazine and water are added into a stirrer and stirred, and the polyurethane-containing fracturing fluid is obtained after stirring is finished. Polyurethane in the fracturing fluid has good temperature resistance, hydrogel is formed through crosslinking, and the hydrogel can still keep stable at high temperature, so that the temperature resistance of the fracturing fluid is improved; quaternary ammonium salt groups and sulfonic acid groups in benzoxazine are modified by sodium sulfonate, so that the drag reduction effect of the fracturing fluid is improved; wherein the benzoxazine structure also has a relatively good high-temperature-resistant effect; and benzene rings contained in the fracturing fluid can be kept stable at high temperature and high pressure, so that the high-temperature resistance of the fracturing fluid is improved.

Description

Technical Field

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

[0002] Fracturing fluid is a common oil and gas production enhancement technology, the purpose of which is to create cracks in the oil and gas layers, thereby increasing production. Existing fracturing fluids include oil-based fracturing fluids, alcohol-based fracturing fluids, water-based fracturing fluids, etc. If used at high temperatures, it requires good high temperature resistance, otherwise it is difficult to meet the requirements.

[0003] For example, application No. 201611147613.3 discloses a clean fracturing fluid and a preparation method thereof. The clean fracturing fluid provided by the invention has a low main agent concentration, low cost, excellent gel and temperature resistance and shear resistance, and expands the application scope of the clean fracturing fluid; however, its resistance reduction effect has not been improved. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention provides a polyurethane-containing fracturing fluid and a preparation method thereof, which has good temperature resistance and resistance reduction effects.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a polyurethane-containing fracturing fluid, comprising the following components by weight: 5-8 parts by weight of hexadecyltrimethylammonium chloride, 2-4 parts by weight of polyurethane, 1-4 parts by weight of sodium formate, 2-3 parts by weight of sodium sulfonate-modified benzoxazine, and 20-24 parts by weight of water.

[0006] Furthermore, the preparation method of the sodium sulfonate modified benzoxazine is: (1) Under a nitrogen atmosphere, add 5.3-5.5 g of bisphenol fluorene and 1-1.2 mL of triethylamine to 45-55 mL of dichloromethane solvent, stir at 8-12 °C until fully dissolved, then continue to add 1.62-1.68 g of phenylphosphoryl dichloride, stir to react, and after completion, obtain a phenol-based intermediate; (2) Adding 1.6-2.4 g of allylamine and an aqueous solution containing 1.8-2.5 g of formaldehyde to a 1,4-dioxane solvent, stirring at 2-5° C. for 1-3 h, then adding 4-5.3 g of a phenol intermediate, stirring at 80-95° C. for a cyclization reaction, distilling under reduced pressure after the reaction, and recrystallizing from ethanol to obtain an olefinated benzoxazine; (3) Add phenylboric acid to toluene solvent, stir and disperse, then add N-methyl-2-hydroxyethylamine, react at 115-120°C for 10-12h, and after the reaction is completed, distill under reduced pressure, filter and dry to obtain intermediate 1; (4) Add intermediate 1 and 3-chloropropylene to N,N-dimethylformamide solvent, stir and disperse, react at 70-80°C for 12-14h, then continue to add sodium 3-chloro-2-hydroxypropanesulfonate, react at 70-85°C for 6-8h, and then distill under reduced pressure and filter to obtain olefinated boronic acid; (5) Add olefinated benzoxazine and olefinated boric acid to N,N-dimethylformamide solvent, stir to dissolve, continue to add azobisisobutyronitrile initiator, react at 95-106°C for 4-7h, and then distill under reduced pressure, wash, and dry to obtain sodium sulfonate modified benzoxazine.

[0007] Furthermore, the reaction time in (1) is 5-7 hours.

[0008] Furthermore, the cyclization reaction time in (2) is 4-6 hours.

[0009] Furthermore, the mass ratio of phenylboric acid to N-methyl-2-hydroxyethylamine in (3) is 1:2.1-2.3.

[0010] Furthermore, in the (4), the mass ratio of the intermediate 1, 3-chloropropylene and sodium 3-chloro-2-hydroxypropanesulfonate is 1:2.11-2.26:1.84-2.17.

[0011] Furthermore, in the (5), the mass ratio of olefinated benzoxazine, olefinated boronic acid, and azobisisobutyronitrile initiator is 1:0.85-1.1:0.01-0.02.

[0012] Furthermore, the preparation method of the polyurethane-containing fracturing fluid is: adding hexadecyltrimethylammonium chloride, polyurethane, sodium formate, sodium sulfonate-modified benzoxazine, and water into a stirrer, stirring for 10-16 minutes, and obtaining the polyurethane-containing fracturing fluid after stirring.

[0013] Beneficial effects: The invention adds hexadecyltrimethylammonium chloride, polyurethane, sodium formate, sodium sulfonate modified benzoxazine and water into a stirrer, and stirs to obtain a polyurethane-containing fracturing fluid.

[0014] The phenolic hydroxyl group in bisphenolfluorene and the chlorine in phenylphosphoryl dichloride are subjected to a substitution reaction to introduce the phenolic hydroxyl group, thereby obtaining a phenol-based intermediate, which is then further subjected to a cyclization reaction with an aqueous solution of allylamine and formaldehyde to obtain an olefinated benzoxazine; the boronic acid group in phenylboronic acid is reacted with the hydroxyl group in N-methyl-2-hydroxyethylamine to introduce a secondary amine, which is then further subjected to a substitution reaction with the chlorine group in 3-chloropropylene and sodium 3-chloro-2-hydroxypropanesulfonate to generate a quaternary ammonium salt group to obtain an olefinated boronic acid.

[0015] The polyurethane in the fracturing fluid itself has good temperature resistance. It forms a hydrogel through cross-linking. The hydrogel can remain stable at high temperatures, which helps to improve the temperature resistance of the fracturing fluid. Sodium sulfonate modifies the quaternary ammonium salt group and sulfonic acid group in benzoxazine to improve the drag reduction effect of the fracturing fluid. The benzoxazine structure itself also has good high temperature resistance and drag reduction effects. The benzene ring contained therein can remain stable under high temperature and high pressure, improving the high temperature resistance of the fracturing fluid. DETAILED DESCRIPTION

[0016] Embodiment 1: (1) Under a nitrogen atmosphere, 5.3 g of bisphenol fluorene and 1 mL of triethylamine were added to 45 mL of dichloromethane solvent and stirred at 8 °C until fully dissolved. Then, 1.62 g of phenylphosphoryl dichloride was added thereto and the reaction was stirred for 5 h. After the reaction, a phenol-based intermediate was obtained. (2) Add 1.6 g of allylamine and an aqueous solution containing 1.8 g of formaldehyde to 20 mL of 1,4-dioxane solvent, stir at 2°C for 1 h, then add 4 g of phenol intermediate, stir at 80°C for 4 h for cyclization reaction, distill under reduced pressure after the reaction, and recrystallize from ethanol to obtain olefinated benzoxazine; (3) Add 1 g of phenylboric acid to 20 mL of toluene solvent, stir and disperse, then add 2.1 g of N-methyl-2-hydroxyethylamine, react at 115 °C for 10 h. After the reaction is completed, distill under reduced pressure, filter and dry to obtain intermediate 1; (4) Add 1 g of intermediate 1 and 2.11 g of 3-chloropropylene to 30 mL of N,N-dimethylformamide solvent, stir and disperse, react at 70 °C for 12 h, then continue to add 1.84 g of sodium 3-chloro-2-hydroxypropanesulfonate, react at 70 °C for 6 h, and then distill under reduced pressure and filter to obtain olefinated boronic acid; (5) Add 1 g of olefinated benzoxazine and 0.85 g of olefinated boric acid to 35 mL of N,N-dimethylformamide solvent, stir to dissolve, and continue to add 0.01 g of azobisisobutyronitrile initiator, react at 95 °C for 4 h, and then distill under reduced pressure, wash, and dry to obtain sodium sulfonate modified benzoxazine; (6) Add 5 parts by weight of hexadecyltrimethylammonium chloride, 2 parts by weight of polyurethane, 1 part by weight of sodium formate, 2 parts by weight of sodium sulfonate-modified benzoxazine, and 20 parts by weight of water into a stirrer and stir for 10 minutes to obtain a fracturing fluid containing polyurethane.

[0017] Embodiment 2:

[0018] (1) Under a nitrogen atmosphere, 5.5 g of bisphenol fluorene and 1.2 mL of triethylamine were added to 55 mL of dichloromethane solvent and stirred at 12 °C until fully dissolved. Then, 1.68 g of phenylphosphoryl dichloride was added thereto and the reaction was stirred for 7 h. After the reaction, a phenol-based intermediate was obtained. (2) Add 2.4 g of allylamine and an aqueous solution containing 2.5 g of formaldehyde to 25 mL of 1,4-dioxane solvent, stir at 5 °C for 3 h, then add 5.3 g of phenol intermediate, stir at 95 °C for 6 h for cyclization reaction, distill under reduced pressure after the reaction, and recrystallize from ethanol to obtain olefinated benzoxazine; (3) Add 1 g of phenylboric acid to 30 mL of toluene solvent, stir and disperse, then add 2.3 g of N-methyl-2-hydroxyethylamine, react at 120 °C for 12 h. After the reaction is completed, distill under reduced pressure, filter and dry to obtain intermediate 1; (4) Add 1 g of intermediate 1 and 2.26 g of 3-chloropropylene to 40 mL of N,N-dimethylformamide solvent, stir and disperse, react at 80 °C for 14 h, then continue to add 2.17 g of sodium 3-chloro-2-hydroxypropanesulfonate, react at 85 °C for 8 h, and then distill under reduced pressure and filter to obtain olefinated boronic acid; (5) Add 1 g of olefinated benzoxazine and 1.1 g of olefinated boric acid to 45 mL of N,N-dimethylformamide solvent, stir to dissolve, and continue to add 0.02 g of azobisisobutyronitrile initiator, react at 106 °C for 7 h, and then distill under reduced pressure, wash, and dry to obtain sodium sulfonate modified benzoxazine; (6) 8 parts by weight of hexadecyltrimethylammonium chloride, 4 parts by weight of polyurethane, 4 parts by weight of sodium formate, 3 parts by weight of sodium sulfonate-modified benzoxazine, and 24 parts by weight of water were added into a stirrer and stirred for 16 minutes to obtain a polyurethane-containing fracturing fluid.

[0019] Embodiment 3:

[0020] (1) Under a nitrogen atmosphere, 5.4 g of bisphenol fluorene and 1.1 mL of triethylamine were added to 50 mL of dichloromethane solvent, and stirred at 10°C until fully dissolved. Then, 1.65 g of phenylphosphoryl dichloride was added thereto, and the reaction was stirred for 6 h. After the reaction, a phenol-based intermediate was obtained. (2) Add 2.1 g of allylamine and an aqueous solution containing 2.2 g of formaldehyde to 22 mL of 1,4-dioxane solvent, stir at 3°C ​​for 2 h, then add 5.1 g of phenol intermediate, stir at 85°C for 5 h for cyclization reaction, distill under reduced pressure after the reaction, and recrystallize from ethanol to obtain olefinated benzoxazine; (3) Add 1 g of phenylboric acid to 25 mL of toluene solvent, stir and disperse, then add 2.2 g of N-methyl-2-hydroxyethylamine, react at 117 °C for 11 h. After the reaction is completed, distill under reduced pressure, filter and dry to obtain intermediate 1; (4) Add 1 g of intermediate 1 and 2.18 g of 3-chloropropylene to 35 mL of N,N-dimethylformamide solvent, stir and disperse, react at 75 °C for 13 h, then continue to add 2.14 g of sodium 3-chloro-2-hydroxypropanesulfonate, react at 75 °C for 7 h, and then distill under reduced pressure and filter to obtain olefinated boronic acid; (5) Add 1 g of olefinated benzoxazine and 0.95 g of olefinated boric acid to 40 mL of N,N-dimethylformamide solvent, stir to dissolve, and continue to add 0.015 g of azobisisobutyronitrile initiator, react at 100 °C for 5 h, and then distill under reduced pressure, wash, and dry to obtain sodium sulfonate modified benzoxazine; (6) 7 parts by weight of hexadecyltrimethylammonium chloride, 3 parts by weight of polyurethane, 2 parts by weight of sodium formate, 2 parts by weight of sodium sulfonate-modified benzoxazine, and 22 parts by weight of water were added into a stirrer and stirred for 13 minutes to obtain a fracturing fluid containing polyurethane.

[0021] Embodiment 4:

[0022] (1) Under a nitrogen atmosphere, 5.3 g of bisphenol fluorene and 1 mL of triethylamine were added to 45 mL of dichloromethane solvent and stirred at 8 °C until fully dissolved. Then, 1.62 g of phenylphosphoryl dichloride was added thereto and the reaction was stirred for 5 h. After the reaction, a phenol-based intermediate was obtained. (2) Add 1.6 g of allylamine and an aqueous solution containing 1.8 g of formaldehyde to 20 mL of 1,4-dioxane solvent, stir at 2°C for 1 h, then add 4 g of phenol intermediate, stir at 80°C for 4 h for cyclization reaction, distill under reduced pressure after the reaction, and recrystallize from ethanol to obtain olefinated benzoxazine; (3) Add 1 g of phenylboric acid to 30 mL of toluene solvent, stir and disperse, then add 2.3 g of N-methyl-2-hydroxyethylamine, react at 120 °C for 12 h. After the reaction is completed, distill under reduced pressure, filter and dry to obtain intermediate 1; (4) Add 1 g of intermediate 1 and 2.26 g of 3-chloropropylene to 40 mL of N,N-dimethylformamide solvent, stir and disperse, react at 80 °C for 14 h, then continue to add 2.17 g of sodium 3-chloro-2-hydroxypropanesulfonate, react at 85 °C for 8 h, and then distill under reduced pressure and filter to obtain olefinated boronic acid; (5) Add 1 g of olefinated benzoxazine and 0.95 g of olefinated boric acid to 40 mL of N,N-dimethylformamide solvent, stir to dissolve, and continue to add 0.015 g of azobisisobutyronitrile initiator, react at 100 °C for 5 h, and then distill under reduced pressure, wash, and dry to obtain sodium sulfonate modified benzoxazine; (6) 7 parts by weight of hexadecyltrimethylammonium chloride, 3 parts by weight of polyurethane, 2 parts by weight of sodium formate, 2 parts by weight of sodium sulfonate-modified benzoxazine, and 22 parts by weight of water were added into a stirrer and stirred for 13 minutes to obtain a fracturing fluid containing polyurethane.

[0023] Comparative Example 1 The difference between this comparative example and Example 4 is that olefinated boronic acid is used instead of sodium sulfonate to modify benzoxazine.

[0024] Comparative Example 2 The difference between this comparative example and Example 4 is that olefinated benzoxazine is used instead of sodium sulfonate to modify benzoxazine.

[0025] The polyurethane-containing fracturing fluid prepared in the examples and comparative examples was added to water to prepare a simulated fracturing fluid with a concentration of 2%. After being stirred evenly, the fracturing fluid was sheared at 70°C, 110°C, and 160°C for 1-4 h, with a shear rate of 170 s -1 The apparent viscosity of the solution was measured using a rotational viscometer. The test results are shown in Table 1.

[0026] Table 1: High temperature resistance test

[0027] As can be seen from Table 1, the viscosity of Examples 1-4 of the present invention and Comparative Examples 1-2 is as high as 802.49 mPa·s at 70°C, as high as 762.29 mPa·s at 110°C, and as high as 706.19 mPa·s at 160°C, indicating that the obtained polyurethane-containing fracturing fluid has good temperature resistance.

[0028] The drag reduction rate was tested with reference to SYT 6376-2008 “General Technical Requirements for Fracturing Fluids”. The test results are shown in Table 2.

[0029] Table 2: Drag reduction test

[0030] It can be seen from Table 2 that Examples 1-4 of the present invention have better drag reduction rates than Comparative Examples 1-2.

[0031] The preferred embodiments of the present invention disclosed above are only used to help illustrate 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. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A fracturing fluid containing polyurethane, characterized in that: The invention comprises the following components by weight: 5-8 parts by weight of hexadecyltrimethylammonium chloride, 2-4 parts by weight of polyurethane, 1-4 parts by weight of sodium formate, 2-3 parts by weight of sodium sulfonate-modified benzoxazine, and 20-24 parts by weight of water.

2. The polyurethane-containing fracturing fluid according to claim 1, characterized in that: The preparation method of the sodium sulfonate modified benzoxazine is as follows: (1) Under a nitrogen atmosphere, add 5.3-5.5 g of bisphenol fluorene and 1-1.2 mL of triethylamine to 45-55 mL of dichloromethane solvent, stir at 8-12 °C until fully dissolved, then continue to add 1.62-1.68 g of phenylphosphoryl dichloride, stir to react, and after completion, obtain a phenol-based intermediate; (2) Adding 1.6-2.4 g of allylamine and an aqueous solution containing 1.8-2.5 g of formaldehyde to a 1,4-dioxane solvent, stirring at 2-5° C. for 1-3 h, then adding 4-5.3 g of a phenol intermediate, stirring at 80-95° C. for a cyclization reaction, distilling under reduced pressure after the reaction, and recrystallizing from ethanol to obtain an olefinated benzoxazine; (3) Add phenylboric acid to toluene solvent, stir and disperse, then add N-methyl-2-hydroxyethylamine, react at 115-120°C for 10-12h, and after the reaction is completed, distill under reduced pressure, filter and dry to obtain intermediate 1; (4) Add intermediate 1 and 3-chloropropylene to N,N-dimethylformamide solvent, stir and disperse, react at 70-80°C for 12-14h, then continue to add sodium 3-chloro-2-hydroxypropanesulfonate, react at 70-85°C for 6-8h, and then distill under reduced pressure and filter to obtain olefinated boronic acid; (5) Add olefinated benzoxazine and olefinated boric acid to N,N-dimethylformamide solvent, stir to dissolve, continue to add azobisisobutyronitrile initiator, react at 95-106°C for 4-7h, and then distill under reduced pressure, wash, and dry to obtain sodium sulfonate modified benzoxazine.

3. The polyurethane-containing fracturing fluid according to claim 2, characterized in that: The reaction time in step (1) is 5-7h.

4. The polyurethane-containing fracturing fluid according to claim 2, characterized in that: The cyclization reaction time in step (2) is 4-6 hours.

5. The polyurethane-containing fracturing fluid according to claim 2, characterized in that: In step (3), the mass ratio of phenylboric acid to N-methyl-2-hydroxyethylamine is 1:2.1-2.

3.

6. The polyurethane-containing fracturing fluid according to claim 2, characterized in that: In step (4), the mass ratio of the intermediate 1, 3-chloropropylene, and sodium 3-chloro-2-hydroxypropanesulfonate is 1:2.11-2.26:1.84-2.

17.

7. The polyurethane-containing fracturing fluid according to claim 2, characterized in that: In step (5), the mass ratio of olefinated benzoxazine, olefinated boronic acid, and azobisisobutyronitrile initiator is 1:0.85-1.1:0.01-0.

02.

8. A method for preparing a polyurethane-containing fracturing fluid according to any one of claims 1 to 7, characterized in that: The preparation method of the polyurethane-containing fracturing fluid is as follows: adding hexadecyltrimethylammonium chloride, polyurethane, sodium formate, sodium sulfonate-modified benzoxazine and water into a stirrer, stirring for 10-16 minutes, and obtaining the polyurethane-containing fracturing fluid after stirring.

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