Fracturing fluid and preparation method thereof

Abstract

The invention relates to the technical field of fracturing fluids, and discloses a fracturing fluid and a preparation method thereof.The preparation method comprises the steps that cardanol modified polyurethane, modified silicone rubber, hexadecyl trimethyl ammonium chloride, sodium salicylate and water are added into a reactor and stirred, and the fracturing fluid is obtained after stirring is finished. Wherein the quaternary ammonium salt group can reduce the reservoir damage by reducing the hydration of clay on the surface of shale and inhibiting the expansion and migration of the clay, can still keep stable performance at high temperature, and is beneficial to improving the temperature resistance of the fracturing fluid; wherein polyurethane 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 can be improved; cardanol in the fracturing fluid has good high temperature resistance, and can maintain the stability and effectiveness of the fracturing fluid under a high temperature condition; the silicon rubber structure contains silicon-oxygen bonds, so that the viscosity of the fracturing fluid can be improved, and meanwhile, the fracturing fluid has good anti-shearing capability in a high-temperature environment.

Description

Technical Field

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

[0002] Fracturing fluid is a heterogeneous and unstable chemical system formed by a variety of additives in a certain ratio. It is used to transfer the high pressure formed by ground equipment to the formation, so that the formation breaks to form cracks and transport proppant along the cracks. Existing fracturing fluids include oil-based fracturing fluids, alcohol-based fracturing fluids, water-based fracturing fluids, etc. With the continuous deepening of oil and gas exploration and development, the requirements for fracturing fluids are getting higher and higher. For example, patent CN110699060A discloses a fracturing fluid and its preparation method. The fracturing fluid of the invention has good fluidity and good sand carrying and crack-making functions, but its shear resistance and high temperature resistance are poor. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the deficiencies in the prior art, the present invention provides a fracturing fluid and a preparation method thereof, which have good high temperature resistance and shear resistance.

[0005] (II) Technical solution

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a fracturing fluid, comprising the following components by weight: 6-10 parts by weight of cardanol-modified polyurethane, 4-12 parts by weight of modified silicone rubber, 4-6 parts by weight of hexadecyltrimethylammonium chloride, 0.4-0.9 parts by weight of sodium salicylate, and 20-40 parts by weight of water.

[0007] Preferably, the preparation method of the cardanol-modified polyurethane is:

[0008] (1) adding erucic acid and methanol into a reactor, stirring evenly, and then adding p-toluenesulfonic acid catalyst thereto, reacting at 65-80° C. for 70-90 minutes, and then rotary evaporating to obtain methyl erucate;

[0009] (2) adding 6-10 parts by weight of methyl erucate and 7-13 parts by weight of N-(3-aminopropyl)diethanolamine to a methanol solvent, adding a sodium hydroxide catalyst having a mass fraction of 10-12% after dissolution, introducing nitrogen protection, reacting at 20-40° C., and after the reaction is completed, removing the solvent by rotary evaporation, washing with a mixed solution of acetone and water, and drying to obtain erucic acid amide propyl dihydroxyethyl tertiary amine;

[0010] (3) adding 3-pentadecylphenoxyethyl bromide and erucic acid amide propyl dihydroxyethyl tertiary amine to an isopropanol solvent, stirring and mixing, reacting at 75-90° C. for 4-6 hours, and washing with deionized water to obtain a quaternary ammonium salt-modified cardanol chain extender;

[0011] (4) After removing water from the polyether diol, mix it evenly with hexamethylene diisocyanate, introduce nitrogen, then drop dibutyltin dilaurate as a catalyst, react at 50-75° C. for 2-5 hours to perform prepolymerization, then add quaternary ammonium salt-modified cardanol chain extender, stir to continue chain extension reaction, react at 50-60° C. for 1-2 hours, and after the reaction is completed, cool and discharge to obtain cardanol-modified polyurethane.

[0012] Preferably, the mass ratio of erucic acid, methanol and p-toluenesulfonic acid catalyst in (1) is 1:1.2-1.3:0.01-0.02.

[0013] Preferably, the reaction time in (2) is 1-2 h.

[0014] Preferably, the mass ratio of 3-pentadecylphenoxyethyl bromide to erucic acid amide propyl dihydroxyethyl tertiary amine in (3) is 1.1-1.4:1.

[0015] Preferably, the mass ratio of the polyether diol, hexamethylene diisocyanate, dibutyltin dilaurate catalyst, and quaternary ammonium salt-modified cardanol chain extender in (4) is 1.3-2:1:0.01-0.03:0.6-0.9.

[0016] Preferably, the preparation method of the modified silicone rubber is:

[0017] S1. Add 0.01-0.02 parts by weight of a polymerization inhibitor, butylated hydroxytoluene, 0.03-0.05 parts by weight of a tetrahydrofuran solution of chloroplatinic acid as a catalyst, and 14-18 parts by weight of maleic acid to N,N-dimethylformamide solvent, stir evenly, then add 12-15 parts by weight of silicone rubber, disperse evenly by ultrasonication, react at 65-90°C for 6-8h, cool after completion, centrifuge, wash and dry to obtain carboxylated silicone rubber;

[0018] S2. Dissolve 8-10 parts by weight of carboxylated silicone rubber and 7-12 parts by weight of quaternary ammonium salt-modified cardanol chain extender in N,N-dimethylformamide solvent, then add 0.03-0.04 parts by weight of N,N-dicyclohexylcarbodiimide and 0.01-0.04 parts by weight of 4-dimethylaminopyridine, reflux at 120-130°C for 20-25h, and after the reaction, remove the solvent by distillation under reduced pressure, precipitate, filter and wash to obtain modified silicone rubber.

[0019] Preferably, the preparation method of the fracturing fluid is: adding cardanol-modified polyurethane, modified silicone rubber, hexadecyltrimethylammonium chloride, sodium salicylate and water into a reactor, stirring for 6-14 minutes, and obtaining the fracturing fluid after the stirring.

[0020] (III) Beneficial technical effects

[0021] The invention provides a fracturing fluid by adding cardanol modified polyurethane, modified silicone rubber, hexadecyltrimethylammonium chloride, sodium salicylate and water into a reactor and stirring the mixture.

[0022] The erucic acid and methanol are subjected to an esterification reaction to obtain methyl erucate, which is then further reacted with N-(3-aminopropyl)diethanolamine to introduce tertiary amine groups and hydroxyl groups, thereby obtaining erucic acid amide propyl dihydroxyethyl tertiary amine; the bromine group in 3-pentadecylphenoxyethyl bromide and the tertiary amine in erucic acid amide propyl dihydroxyethyl tertiary amine are subjected to a quaternization reaction to obtain a quaternary ammonium salt-modified cardanol chain extender; polyether diol and hexamethylene diisocyanate are reacted, and then a quaternary ammonium salt-modified cardanol chain extender is added to obtain a cardanol-modified polyurethane; the olefin group in maleic acid is subjected to an addition reaction with silicone rubber to introduce a carboxyl group, thereby obtaining a carboxylated silicone rubber, which is further reacted with a hydroxyl group in the quaternary ammonium salt-modified cardanol chain extender to increase the degree of substitution of the silicone rubber structure, thereby obtaining a modified silicone rubber.

[0023] The quaternary ammonium salt groups can reduce the damage to the reservoir by reducing the clay hydration on the surface of the shale and inhibiting the expansion and migration of the clay. They can also maintain stable performance at high temperatures, which helps to improve the temperature resistance of the fracturing fluid. The polyurethane itself has good temperature resistance and forms a hydrogel through cross-linking. This hydrogel can remain stable at high temperatures, which helps to improve the temperature resistance of the fracturing fluid. The cardanol has good high temperature resistance and can maintain the stability and effectiveness of the fracturing fluid under high temperature conditions. The silicone rubber structure contains silicon-oxygen bonds, which can increase the viscosity of the fracturing fluid and make it have good shear resistance in high temperature environments. The carboxylated silicone rubber reacts with the quaternary ammonium salt-modified cardanol chain extender to increase the degree of substitution of the silicone rubber and further improve its shear resistance. DETAILED DESCRIPTION

[0024] The preparation method of 3-pentadecylphenoxyethyl bromide refers to the literature "Synthesis of Fullerene-Cardanol Derivatives", SYNLETT, 2004, No. 5, pp 0799-08020. 2 g of 3-pentadecylphenol was added to 8 mL of 1,2-bromoethane, and 0.55 g of potassium hydroxide was added, and the mixture was stirred at 70° C. for 6 h, and 3-pentadecylphenoxyethyl bromide was obtained by column chromatography separation.

[0025] Example 1

[0026] (1) adding erucic acid and methanol into a reactor, stirring evenly, and then adding p-toluenesulfonic acid catalyst, wherein the mass ratio of erucic acid, methanol, and p-toluenesulfonic acid catalyst is 1:1.2:0.01, reacting at 65° C. for 70 minutes, and then rotary evaporating to obtain methyl erucate;

[0027] (2) adding 6 parts by weight of methyl erucate and 7 parts by weight of N-(3-aminopropyl)diethanolamine to a methanol solvent, adding a sodium hydroxide catalyst having a mass fraction of 10% after dissolution, introducing nitrogen protection, reacting at 20° C. for 1 hour, and after the reaction is completed, removing the solvent by rotary evaporation, washing with a mixed solution of acetone and water, and drying to obtain erucic acid amide propyl dihydroxyethyl tertiary amine;

[0028] (3) adding 3-pentadecylphenoxyethyl bromide and erucic acid amide propyl dihydroxyethyl tertiary amine to an isopropanol solvent, wherein the mass ratio of 3-pentadecylphenoxyethyl bromide to erucic acid amide propyl dihydroxyethyl tertiary amine is 1.1:1, stirring and mixing, reacting at 75° C. for 4 hours, and washing with deionized water after completion to obtain a quaternary ammonium salt modified cardanol chain extender;

[0029] (4) removing water from the polyether diol and mixing it evenly with hexamethylene diisocyanate, introducing nitrogen, then dropping a dibutyltin dilaurate catalyst, reacting at 50° C. for 2 hours, performing prepolymerization, and then adding a quaternary ammonium salt-modified cardanol chain extender, wherein the mass ratio of the polyether diol, hexamethylene diisocyanate, dibutyltin dilaurate catalyst, and quaternary ammonium salt-modified cardanol chain extender is 1.3:1:0.01:0.6, stirring to continue the chain extension reaction, reacting at 50° C. for 1 hour, and after the reaction is completed, cooling and discharging to obtain a cardanol-modified polyurethane;

[0030] (5) Add 0.01 parts by weight of a polymerization inhibitor, butylated hydroxytoluene, 0.03 parts by weight of a tetrahydrofuran solution of chloroplatinic acid as a catalyst, and 14 parts by weight of maleic acid to an N,N-dimethylformamide solvent, stir evenly, then add 12 parts by weight of silicone rubber, disperse evenly by ultrasonication, react at 65° C. for 6 h, cool after reaction, centrifuge, wash and dry to obtain a carboxylated silicone rubber;

[0031] (6) dissolving 8 parts by weight of carboxylated silicone rubber and 7 parts by weight of quaternary ammonium salt-modified cardanol chain extender in N,N-dimethylformamide solvent, then adding 0.03 parts by weight of N,N-dicyclohexylcarbodiimide and 0.01 parts by weight of 4-dimethylaminopyridine, reflux at 120° C. for 20 h, and after the reaction, removing the solvent by reduced pressure distillation, precipitating, filtering and washing to obtain modified silicone rubber;

[0032] (7) 6 parts by weight of cardanol-modified polyurethane, 4 parts by weight of modified silicone rubber, 4 parts by weight of hexadecyltrimethylammonium chloride, 0.4 parts by weight of sodium salicylate, and 20 parts by weight of water were added into a reactor and stirred for 6 minutes to obtain a fracturing fluid.

[0033] Example 2

[0034] (1) adding erucic acid and methanol into a reactor, stirring evenly, and then adding p-toluenesulfonic acid catalyst, wherein the mass ratio of erucic acid, methanol, and p-toluenesulfonic acid catalyst is 1:1.3:0.02, reacting at 80° C. for 90 minutes, and then rotary evaporating to obtain methyl erucate;

[0035] (2) adding 10 parts by weight of methyl erucate and 13 parts by weight of N-(3-aminopropyl)diethanolamine to a methanol solvent, adding a sodium hydroxide catalyst having a mass fraction of 12% after dissolution, introducing nitrogen protection, reacting at 40° C. for 2 h, and after the reaction is completed, removing the solvent by rotary evaporation, washing with a mixed solution of acetone and water, and drying to obtain erucic acid amide propyl dihydroxyethyl tertiary amine;

[0036] (3) adding 3-pentadecylphenoxyethyl bromide and erucic acid amide propyl dihydroxyethyl tertiary amine to an isopropanol solvent, wherein the mass ratio of 3-pentadecylphenoxyethyl bromide to erucic acid amide propyl dihydroxyethyl tertiary amine is 1.4:1, stirring and mixing, reacting at 90° C. for 6 hours, and washing with deionized water after completion to obtain a quaternary ammonium salt modified cardanol chain extender;

[0037] (4) After removing water from the polyether diol, mix it evenly with hexamethylene diisocyanate, introduce nitrogen, then dropwise add dibutyltin dilaurate catalyst, react at 75° C. for 5 hours, perform prepolymerization, and then add quaternary ammonium salt modified cardanol chain extender, wherein the mass ratio of polyether diol, hexamethylene diisocyanate, dibutyltin dilaurate catalyst, and quaternary ammonium salt modified cardanol chain extender is 2:1:0.03:0.9, stir to continue chain extension reaction, react at 60° C. for 2 hours, and after the reaction is completed, cool and discharge to obtain cardanol modified polyurethane;

[0038] (5) Add 0.02 parts by weight of a polymerization inhibitor, butylated hydroxytoluene, 0.05 parts by weight of a tetrahydrofuran solution of chloroplatinic acid as a catalyst, and 18 parts by weight of maleic acid to an N,N-dimethylformamide solvent, stir evenly, then add 15 parts by weight of silicone rubber, disperse evenly by ultrasonication, react at 90° C. for 8 h, cool after reaction, centrifuge, wash and dry to obtain a carboxylated silicone rubber;

[0039] (6) dissolving 10 parts by weight of carboxylated silicone rubber and 12 parts by weight of quaternary ammonium salt-modified cardanol chain extender in N,N-dimethylformamide solvent, then adding 0.04 parts by weight of N,N-dicyclohexylcarbodiimide and 0.04 parts by weight of 4-dimethylaminopyridine, reflux at 130° C. for 25 h, and after the reaction, removing the solvent by reduced pressure distillation, precipitating, filtering and washing to obtain modified silicone rubber;

[0040] (7) 10 parts by weight of cardanol-modified polyurethane, 12 parts by weight of modified silicone rubber, 6 parts by weight of hexadecyltrimethylammonium chloride, 0.9 parts by weight of sodium salicylate, and 40 parts by weight of water were added into a reactor and stirred for 14 minutes to obtain a fracturing fluid.

[0041] Example 3

[0042] (1) adding erucic acid and methanol into a reactor, stirring evenly, and then adding p-toluenesulfonic acid catalyst, wherein the mass ratio of erucic acid, methanol, and p-toluenesulfonic acid catalyst is 1:1.25:0.015, reacting at 75° C. for 80 minutes, and then rotary evaporating to obtain methyl erucate;

[0043] (2) adding 8 parts by weight of methyl erucate and 10 parts by weight of N-(3-aminopropyl)diethanolamine to a methanol solvent, adding a sodium hydroxide catalyst having a mass fraction of 11% after dissolution, introducing nitrogen protection, reacting at 30° C. for 1.5 hours, and after the reaction is completed, removing the solvent by rotary evaporation, washing with a mixed solution of acetone and water, and drying to obtain erucic acid amide propyl dihydroxyethyl tertiary amine;

[0044] (3) adding 3-pentadecylphenoxyethyl bromide and erucic acid amide propyl dihydroxyethyl tertiary amine to an isopropanol solvent, wherein the mass ratio of 3-pentadecylphenoxyethyl bromide to erucic acid amide propyl dihydroxyethyl tertiary amine is 1.2:1, stirring and mixing, reacting at 82° C. for 5 h, and washing with deionized water after completion to obtain a quaternary ammonium salt modified cardanol chain extender;

[0045] (4) After removing water from the polyether diol, mix it evenly with hexamethylene diisocyanate, introduce nitrogen, then add dibutyltin dilaurate catalyst dropwise, react at 62° C. for 4 hours, perform prepolymerization, and then add quaternary ammonium salt modified cardanol chain extender, wherein the mass ratio of polyether diol, hexamethylene diisocyanate, dibutyltin dilaurate catalyst, and quaternary ammonium salt modified cardanol chain extender is 1.6:1:0.02:0.8, stir to continue chain extension reaction, react at 55° C. for 1.5 hours, and after the reaction is completed, cool and discharge to obtain cardanol modified polyurethane;

[0046] (5) Add 0.015 parts by weight of a polymerization inhibitor, butylated hydroxytoluene, 0.04 parts by weight of a tetrahydrofuran solution of chloroplatinic acid as a catalyst, and 16 parts by weight of maleic acid to an N,N-dimethylformamide solvent, stir evenly, then add 13 parts by weight of silicone rubber, disperse evenly by ultrasonication, react at 75° C. for 7 h, cool after reaction, centrifuge, wash and dry to obtain a carboxylated silicone rubber;

[0047] (6) dissolving 9 parts by weight of carboxylated silicone rubber and 10 parts by weight of quaternary ammonium salt-modified cardanol chain extender in N,N-dimethylformamide solvent, then adding 0.035 parts by weight of N,N-dicyclohexylcarbodiimide and 0.02 parts by weight of 4-dimethylaminopyridine, reflux at 125° C. for 23 h, and after the reaction, removing the solvent by reduced pressure distillation, precipitating, filtering and washing to obtain modified silicone rubber;

[0048] (7) 8 parts by weight of cardanol-modified polyurethane, 9 parts by weight of modified silicone rubber, 5 parts by weight of hexadecyltrimethylammonium chloride, 0.7 parts by weight of sodium salicylate, and 30 parts by weight of water were added into a reactor and stirred for 10 minutes to obtain a fracturing fluid.

[0049] Comparative Example 1

[0050] The difference between this comparative example and Example 3 without adding cardanol is that no cardanol-modified polyurethane is added.

[0051] Comparative Example 2

[0052] The difference between this comparative example and Example 3 without addition is that no modified silicone rubber is added.

[0053] The fracturing fluid prepared in the embodiment and the comparative example was added into water to prepare a simulated fracturing fluid with a concentration of 2%. After being stirred evenly, the mixture was sheared at 25°C, 80°C and 150°C for 1-4h at a shear rate of 170s. -1 The apparent viscosity of the solution was measured using a rotational viscometer. The test results are shown in Table 1.

[0054] Table 1: High temperature resistance test.

[0055]

[0056]

[0057] As can be seen from Table 1, compared with Comparative Examples 1-2, the viscosity of Examples 1-3 of the present invention at different temperatures changes less, indicating that they have better temperature resistance.

[0058] Refer to SYT6376-2008 "General Technical Conditions for Fracturing Fluids" and test the apparent viscosity and shear resistance at 150°C.

[0059] Table 2: Shear performance test.

[0060] project Apparent viscosity (mPa·s) Viscosity after shear (mPa·s) Example 1 98 96 Example 2 99 98 Example 3 98 97 Comparative Example 1 57 53 Comparative Example 2 55 51

[0061] It can be seen from Table 2 that Examples 1-3 of the present invention have better shear performance than Comparative Examples 1-2.

[0062] 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, characterized in that: The invention comprises the following components by weight: 6-10 parts by weight of cardanol modified polyurethane, 4-12 parts by weight of modified silicone rubber, 4-6 parts by weight of hexadecyltrimethylammonium chloride, 0.4-0.9 parts by weight of sodium salicylate and 20-40 parts by weight of water.

2. The fracturing fluid according to claim 1, characterized in that: The preparation method of the cardanol modified polyurethane is: (1) adding erucic acid and methanol into a reactor, stirring evenly, and then adding p-toluenesulfonic acid catalyst thereto, reacting at 65-80° C. for 70-90 minutes, and then rotary evaporating to obtain methyl erucate; (2) adding 6-10 parts by weight of methyl erucate and 7-13 parts by weight of N-(3-aminopropyl)diethanolamine to a methanol solvent, adding a sodium hydroxide catalyst having a mass fraction of 10-12% after dissolution, introducing nitrogen protection, reacting at 20-40° C., and after the reaction is completed, removing the solvent by rotary evaporation, washing with a mixed solution of acetone and water, and drying to obtain erucic acid amide propyl dihydroxyethyl tertiary amine; (3) adding 3-pentadecylphenoxyethyl bromide and erucic acid amide propyl dihydroxyethyl tertiary amine to an isopropanol solvent, stirring and mixing, reacting at 75-90° C. for 4-6 hours, and washing with deionized water to obtain a quaternary ammonium salt-modified cardanol chain extender; (4) After removing water from the polyether diol, mix it evenly with hexamethylene diisocyanate, introduce nitrogen, then drop dibutyltin dilaurate as a catalyst, react at 50-75° C. for 2-5 hours to perform prepolymerization, then add quaternary ammonium salt-modified cardanol chain extender, stir to continue chain extension reaction, react at 50-60° C. for 1-2 hours, and after the reaction is completed, cool and discharge to obtain cardanol-modified polyurethane.

3. The fracturing fluid according to claim 2, characterized in that: The mass ratio of erucic acid, methanol and p-toluenesulfonic acid catalyst in (1) is 1:1.2-1.3:0.01-0.

02.

4. The fracturing fluid according to claim 2, characterized in that: The reaction time in (2) is 1-2h.

5. The fracturing fluid according to claim 2, characterized in that: The mass ratio of 3-pentadecylphenoxyethyl bromide to erucic acid amide propyl dihydroxyethyl tertiary amine in (3) is 1.1-1.4:

1.

6. The fracturing fluid according to claim 2, characterized in that: The mass ratio of the polyether diol, hexamethylene diisocyanate, dibutyltin dilaurate catalyst, and quaternary ammonium salt-modified cardanol chain extender in (4) is 1.3-2:1:0.01-0.03:0.6-0.

9.

7. The fracturing fluid according to claim 1, characterized in that: The preparation method of the modified silicone rubber is: S1. Add 0.01-0.02 parts by weight of a polymerization inhibitor, butylated hydroxytoluene, 0.03-0.05 parts by weight of a tetrahydrofuran solution of chloroplatinic acid as a catalyst, and 14-18 parts by weight of maleic acid to N,N-dimethylformamide solvent, stir evenly, then add 12-15 parts by weight of silicone rubber, disperse evenly by ultrasonication, react at 65-90°C for 6-8h, cool after completion, centrifuge, wash and dry to obtain carboxylated silicone rubber; S2. Dissolve 8-10 parts by weight of carboxylated silicone rubber and 7-12 parts by weight of quaternary ammonium salt-modified cardanol chain extender in N,N-dimethylformamide solvent, then add 0.03-0.04 parts by weight of N,N-dicyclohexylcarbodiimide and 0.01-0.04 parts by weight of 4-dimethylaminopyridine, reflux at 120-130°C for 20-25h, and after the reaction, remove the solvent by distillation under reduced pressure, precipitate, filter and wash to obtain modified silicone rubber.

8. A method for preparing a fracturing fluid according to any one of claims 1 to 7, characterized in that: The preparation method of the fracturing fluid is as follows: adding cardanol modified polyurethane, modified silicone rubber, hexadecyltrimethylammonium chloride, sodium salicylate and water into a reactor, stirring for 6-14 minutes, and obtaining the fracturing fluid after stirring.

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