Composite viscosity enhancer containing sulfonic acid group copolymer in fracturing fluid and preparation method thereof

Abstract

The present invention discloses a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid in the field of tackifier technology and a preparation method thereof. The composite tackifier is prepared from the following components in parts by weight: 65-75 parts of acrylamide, 6-8 parts of acrylic acid, 15-20 parts of sodium 3-allyloxy-2-hydroxy-1-propanesulfonate, 1.2-1.8 parts of a cationic long-chain monomer, 50-60 parts of deionized water, 2-3 parts of Span-80, and 20-30 parts of white oil. The present invention synthesizes an intermediate having an imidazole and a benzene ring structure through ethyleneaniline, glyoxal, and formaldehyde, introduces an alkyl long chain with hexadecane bromide, obtains a cationic long-chain monomer, introduces a monomer with a cation, a hydrophobic long chain, and a rigid structure into the copolymer, and improves the temperature and salt resistance of the sulfonic acid group tackifier.

Description

Technical Field

[0001] The invention belongs to the technical field of tackifiers, and specifically relates to a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid and a preparation method thereof. Background Art

[0002] Petroleum is an important energy source closely related to economic construction and development. With the rapid development of the economy, the global demand for crude oil continues to rise. Fracturing fluid that can adapt to high temperature, high pressure and complex downhole conditions has become one of the key technologies to ensure the drilling and completion of deep and ultra-deep wells. Fracturing fluid systems are mainly divided into oil-based fracturing fluids, water-based fracturing fluids, alcohol-based fracturing fluids, foam fracturing fluids, clean fracturing fluids and other types according to the type of fracturing fluid liquid phase medium. Viscosifiers are one of their main added components. Affected by temperature, acrylamide polymers are prone to chemical degradation under high temperature conditions. At the same time, in brine, when the amide group has a high degree of hydrolysis, the viscosity of the polymer solution will show a corresponding loss. Therefore, the introduction of groups with relatively high temperature resistance and salt resistance can reduce the negative effects of temperature and salt on the viscosity of the solution. However, blindly increasing the temperature resistance and salt resistance groups by introducing monomers often leads to poor polymer stability, poor product quality, expensive synthesis costs and complex processes.

[0003] The existing technology currently has the following main problems: the copolymer tackifier has poor temperature and salt resistance. Summary of the Invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a composite thickener containing a sulfonic acid group copolymer in a fracturing fluid and a preparation method thereof. In order to solve the problem of poor temperature and salt resistance of the copolymer thickener, the present invention proposes to synthesize an intermediate with an imidazole and benzene ring structure through ethyleneaniline, glyoxal and formaldehyde, introduce an alkyl long chain with hexabromide to obtain a cationic long-chain monomer, and at the same time introduce a monomer with a cationic, hydrophobic long chain and a rigid structure into the copolymer through a polymerization reaction to obtain a new tetrapolymer, thereby achieving improved temperature and salt resistance of the thickener.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid, which is prepared from the following components in parts by weight: 65-75 parts of acrylamide, 6-8 parts of acrylic acid, 15-20 parts of sodium 3-allyloxy-2-hydroxy-1-propane sulfonate, 1.2-1.8 parts of a cationic long-chain monomer, 50-60 parts of deionized water, 2-3 parts of Span-80, and 20-30 parts of white oil.

[0006] Preferably, the cationic long-chain monomer is prepared by comprising the following components in parts by weight: 110-130 parts of ethyleneaniline, 56-62 parts of glyoxal, 50-55 parts of ammonium chloride, 60-68 parts of formaldehyde and 300-350 parts of hexadecane bromide.

[0007] Preferably, the method for preparing the cationic long-chain monomer comprises the following steps:

[0008] S1. Add 4-vinylaniline to methanol solution, stir to dissolve, add glyoxal dropwise under nitrogen protection, stir evenly to obtain a mixed solution;

[0009] S2, adding the mixed solution obtained in S1 to the methanol solution, mixing well, adding ammonium chloride, then adding formaldehyde dropwise, and reflux reaction to obtain a reaction solution;

[0010] S3, the reaction solution obtained in S2 was concentrated to 10-15% of the original volume by rotary evaporation, the pH was adjusted to 9, the organic phase was extracted with dichloromethane, filtered, the solvent was evaporated, and dried to obtain the intermediate;

[0011] S4. Add the intermediate obtained in S3 to hexadecane bromide, stir in an oil bath under nitrogen protection, cool, and dry to obtain a cationic long-chain monomer.

[0012] Preferably, in S1, the amount of 4-vinylaniline added to the methanol solution is 0.2-0.25 g / mL.

[0013] Preferably, in S2, the amount of the mixed solution added to the methanol solution is 0.25-0.35 g / mL.

[0014] Preferably, in S2, the reflux reaction temperature is 60-70°C and the time is 8-10 hours.

[0015] Preferably, in S4, the oil bath is stirred at a temperature of 120-150° C., a speed of 50-60 rpm, and a time of 15-20 h.

[0016] The present invention also provides a method for preparing a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid, which specifically comprises the following steps:

[0017] Acrylamide, acrylic acid, sodium 3-allyloxy-2-hydroxy-1-propane sulfonate and a cationic long-chain monomer are added to a reactor in sequence, followed by deionized water and Span-80, and the pH is adjusted to 10. Under nitrogen protection, 0.06-0.08% of ammonium persulfate by weight of the polymer monomer and 0.06-0.08% of sodium bisulfite by weight of the polymer monomer are added, and finally white oil is added, stirred evenly, and stirred in a water bath at 20-30°C at 60-80 rpm for 4 hours to obtain a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid.

[0018] The beneficial effects achieved by the present invention are as follows: the present invention synthesizes an intermediate having an imidazole and a benzene ring structure through ethyleneaniline, glyoxal and formaldehyde, and introduces an alkyl long chain to obtain a cationic long-chain monomer having a rigid benzene ring structure, large steric hindrance and a shielding effect on the main chain, and the alkyl long chain improves the hydrophobicity of the side chain and enhances the viscosity of the polymer; through a polymerization reaction, a monomer having a cation, a hydrophobic long chain and a rigid structure is introduced into the copolymer to obtain a novel tetrapolymer, thereby achieving improved temperature and salt resistance of the sulfonic acid group thickener; the highly polar sulfonic acid group in sodium 3-allyloxy-2-hydroxy-1-propane sulfonate can make the hydration layer denser, increase the energy barrier for cations to penetrate the hydration, reduce the electrostatic shielding of cations on negatively charged groups in the environment, and improve the salt resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The results of the salt tolerance test of Examples 1-3 and Comparative Examples 1-2 of the present invention are shown in FIG.

[0020] Figure 2 The results of the heat resistance tests of Examples 1-3 and Comparative Examples 1-2 of the present invention are shown in FIG.

[0021] Figure 3 This is a synthetic flow chart of the cationic long-chain monomer prepared in the present invention;

[0022] Figure 4 The synthetic flow chart of the sulfonic acid copolymer prepared in the present invention is shown in FIG.

[0023] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0026] The experimental methods in the following examples are conventional methods unless otherwise specified; the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0027] Example 1

[0028] A composite tackifier containing a sulfonic acid copolymer in a fracturing fluid is prepared from the following components in parts by weight: 65 parts of acrylamide, 6 parts of acrylic acid, 15 parts of sodium 3-allyloxy-2-hydroxy-1-propane sulfonate, 1.2 parts of a cationic long-chain monomer, 50 parts of deionized water, 2 parts of Span-80, and 20 parts of white oil.

[0029] The cationic long-chain monomer is prepared by comprising the following components in parts by weight: 110 parts of ethyleneaniline, 56 parts of glyoxal, 50 parts of ammonium chloride, 60 parts of formaldehyde and 300 parts of hexadecane bromide.

[0030] The preparation method of the cationic long-chain monomer specifically comprises the following steps:

[0031] S1. Add 0.2 g / mL of 4-vinylaniline to a methanol solution, stir to dissolve, add glyoxal dropwise under nitrogen, and stir to obtain a mixed solution;

[0032] S2. The mixed solution obtained in S1 was added to the methanol solution at an addition amount of 0.25 g / mL. After mixing, ammonium chloride was added, and then formaldehyde was added dropwise. The mixture was refluxed at 60° C. for 8 h to obtain a reaction solution.

[0033] S3, the reaction solution obtained in S2 was concentrated to 10% of the original volume by rotary evaporation, the pH was adjusted to 9, the organic phase was extracted with dichloromethane, filtered, the solvent was evaporated, and dried to obtain the intermediate;

[0034] S4. Add the intermediate obtained in S3 to hexadecane bromide, stir in an oil bath at 120°C and 50 rpm under nitrogen protection for 15 h, cool and dry to obtain a cationic long-chain monomer.

[0035] The present invention also provides a method for preparing a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid, which specifically comprises the following steps:

[0036] Acrylamide, acrylic acid, sodium 3-allyloxy-2-hydroxy-1-propane sulfonate and cationic long-chain monomers were added to the reactor in sequence, followed by deionized water and Span-80, and the pH was adjusted to 10. Under nitrogen protection, 0.06% of ammonium persulfate by weight of the polymer monomer and 0.06% of sodium bisulfite by weight of the polymer monomer were added, and finally white oil was added. The mixture was stirred evenly and stirred at 60 rpm in a 20°C water bath for 4 h to obtain a composite viscosifier containing a sulfonic acid group copolymer in the fracturing fluid.

[0037] Example 2

[0038] A composite tackifier containing a sulfonic acid copolymer in a fracturing fluid is prepared from the following components in parts by weight: 75 parts of acrylamide, 8 parts of acrylic acid, 20 parts of sodium 3-allyloxy-2-hydroxy-1-propane sulfonate, 1.8 parts of a cationic long-chain monomer, 60 parts of deionized water, 3 parts of Span-80, and 30 parts of white oil.

[0039] The cationic long-chain monomer is prepared by comprising the following components in parts by weight: 130 parts of ethylene aniline, 62 parts of glyoxal, 55 parts of ammonium chloride, 68 parts of formaldehyde and 350 parts of hexadecane bromide.

[0040] The preparation method of the cationic long-chain monomer specifically comprises the following steps:

[0041] S1. Add 0.25 g / mL of 4-vinylaniline to a methanol solution, stir to dissolve, add glyoxal dropwise under nitrogen protection, and stir to obtain a mixed solution;

[0042] S2. The mixed solution obtained in S1 was added to the methanol solution at an addition amount of 0.35 g / mL. After mixing, ammonium chloride was added, and then formaldehyde was added dropwise. The mixture was refluxed at 70° C. for 10 h to obtain a reaction solution.

[0043] S3, the reaction solution obtained in S2 was concentrated to 15% of the original volume by rotary evaporation, the pH was adjusted to 9, the organic phase was extracted with dichloromethane, filtered, the solvent was evaporated, and dried to obtain the intermediate;

[0044] S4. Add the intermediate obtained in S3 to hexadecane bromide, stir in an oil bath at 150°C and 60 rpm under nitrogen protection for 20 h, cool and dry to obtain a cationic long-chain monomer.

[0045] The present invention also provides a method for preparing a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid, which specifically comprises the following steps:

[0046] Acrylamide, acrylic acid, sodium 3-allyloxy-2-hydroxy-1-propane sulfonate and cationic long-chain monomers were added to the reactor in sequence, followed by deionized water and Span-80, and the pH was adjusted to 10. Under nitrogen protection, 0.08% of ammonium persulfate by weight of the polymer monomer and 0.08% of sodium bisulfite by weight of the polymer monomer were added, and finally white oil was added. The mixture was stirred evenly and stirred at 80 rpm in a 30°C water bath for 4 h to obtain a composite viscosifier containing a sulfonic acid group copolymer in the fracturing fluid.

[0047] Example 3

[0048] A composite tackifier containing a sulfonic acid copolymer in a fracturing fluid is prepared from the following components in parts by weight: 70 parts of acrylamide, 7 parts of acrylic acid, 17.5 parts of sodium 3-allyloxy-2-hydroxy-1-propane sulfonate, 1.5 parts of a cationic long-chain monomer, 55 parts of deionized water, 2.5 parts of Span-80, and 25 parts of white oil.

[0049] The cationic long-chain monomer is prepared by comprising the following components in parts by weight: 125 parts of ethylene aniline, 60 parts of glyoxal, 52.5 parts of ammonium chloride, 64 parts of formaldehyde and 325 parts of hexadecane bromide.

[0050] The preparation method of the cationic long-chain monomer specifically comprises the following steps:

[0051] S1. Add 0.225 g / mL of 4-vinylaniline to a methanol solution, stir to dissolve, add glyoxal dropwise under nitrogen protection, and stir to obtain a mixed solution;

[0052] S2. The mixed solution obtained in S1 was added to the methanol solution at an addition amount of 0.3 g / mL. After mixing, ammonium chloride was added, followed by dropwise addition of formaldehyde. The mixture was refluxed at 65° C. for 9 h to obtain a reaction solution.

[0053] S3, the reaction solution obtained in S2 was concentrated to 12.5% of the original volume by rotary evaporation, the pH was adjusted to 9, the organic phase was extracted with dichloromethane, filtered, the solvent was evaporated, and dried to obtain the intermediate;

[0054] S4. Add the intermediate obtained in S3 to hexadecane bromide, stir in an oil bath at 135°C and 55 rpm under nitrogen protection for 17.5 h, cool and dry to obtain a cationic long-chain monomer.

[0055] The present invention also provides a method for preparing a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid, which specifically comprises the following steps:

[0056] Acrylamide, acrylic acid, sodium 3-allyloxy-2-hydroxy-1-propane sulfonate and cationic long-chain monomers were added to the reactor in sequence, followed by deionized water and Span-80, and the pH was adjusted to 10. Under nitrogen protection, 0.07% of ammonium persulfate by weight of the polymer monomer and 0.07% of sodium bisulfite by weight of the polymer monomer were added, and finally white oil was added. The mixture was stirred evenly and stirred at 70 rpm in a water bath at 25°C for 4 hours to obtain a composite viscosity enhancer containing a sulfonic acid group copolymer in the fracturing fluid.

[0057] Comparative Example 1

[0058] This comparative example provides a tackifier, which differs from Example 1 only in that styrene and 1-hexadecene are used in equal molar amounts to replace the cationic long-chain monomer in all components, and the remaining components and component contents are the same as those in Example 1.

[0059] Comparative Example 2

[0060] This comparative example provides a tackifier, which differs from Example 1 only in that all components do not contain a cationic long-chain monomer, and the remaining components and component contents are the same as those in Example 1.

[0061] Experimental example

[0062] The rheometer used in the experiment was RS600 rheometer, and the shear rate was 100s -1 .

[0063] 1. Salt tolerance test

[0064] The solutions of Examples 1-3 and Comparative Examples 1-2 were prepared into 1.6 wt% aqueous solutions with deionized water. The apparent viscosities were tested in 0.1 g / mL to 1 g / mL NaCl solutions at 30°C. The apparent viscosity reduction rate was calculated using the following formula:

[0065] Apparent viscosity decrease rate = (0.1 g / mL apparent viscosity + 1 g / mL apparent viscosity) / 0.1 g / mL apparent viscosity.

[0066] Figure 1 The results of the salt resistance test of Examples 1-3 and Comparative Examples 1-2 of the present invention are shown in the figure; as shown in the figure, the apparent viscosity reduction rates of Examples 1-3 and Comparative Examples 1-2 are 33.9%, 31.6%, 32.7% and 56.6%, 63.2%, respectively. The apparent viscosity reduction rate of Example 1-3 is significantly lower than that of Comparative Example 1-2, indicating that the use of cationic long-chain monomers enhances the salt resistance of the thickener.

[0067] 2. Heat resistance test

[0068] Example 1-3 and Comparative Example 1-2 were prepared into 1.6 wt% aqueous solutions with deionized water. The temperature was raised from 30°C at a rate of 3°C / min. The apparent viscosities at 30°C and 90°C were recorded, and the apparent viscosity reduction rate was calculated using the following formula:

[0069] Apparent viscosity decrease rate = (apparent viscosity at 30°C - apparent viscosity at 90°C) / apparent viscosity at 30°C.

[0070] Figure 2 The results of the heat resistance test of Examples 1-3 and Comparative Examples 1-2 of the present invention are shown in the figure. As shown in the figure, the apparent viscosity reduction rates of Examples 1-3 and Comparative Examples 1-2 are 22.3%, 22.6%, and 22.1% and 45.3% and 53.2%, respectively. The apparent viscosity reduction rate of Example 1-3 is significantly lower than that of Comparative Example 1-2, indicating that the use of cationic long-chain monomers enhances the temperature resistance of the tackifier.

[0071] Figure 3This is a synthetic flow chart of the cationic long-chain monomer prepared in the present invention; as shown in the figure, the monomer has a rigid benzene ring structure, a positively charged group and a hydrophobic long chain.

[0072] Figure 4 The synthetic flow chart of the sulfonic acid copolymer prepared by the present invention is shown in the figure. As shown in the figure, the copolymer is a tetrapolymer composed of acrylamide, acrylic acid, sodium 3-allyloxy-2-hydroxy-1-propane sulfonate and a cationic long-chain monomer.

[0073] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

[0074] The present invention and its embodiments are described above. Such description is not restrictive. The drawings show only one embodiment of the present invention, and actual applications are not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, any method and embodiment similar to the technical solution without creative design shall fall within the scope of protection of the present invention.

Claims

1. A composite tackifier containing a sulfonic acid copolymer in a fracturing fluid, characterized in that: The invention comprises the following components in parts by weight: 65-75 parts of acrylamide, 6-8 parts of acrylic acid, 15-20 parts of sodium 3-allyloxy-2-hydroxy-1-propane sulfonate, 1.2-1.8 parts of cationic long-chain monomer, 50-60 parts of deionized water, 2-3 parts of Span-80 and 20-30 parts of white oil; The cationic long-chain monomer is prepared from the following components in parts by weight: 110-130 parts of ethylene aniline, 56-62 parts of glyoxal, 50-55 parts of ammonium chloride, 60-68 parts of formaldehyde and 300-350 parts of hexadecane bromide; The structure of the cationic long-chain monomer is: ； The preparation method of the cationic long-chain monomer specifically comprises the following steps: S1. Add 4-vinylaniline to methanol solution, stir to dissolve, add glyoxal dropwise under nitrogen protection, stir evenly to obtain a mixed solution; S2, adding the mixed solution obtained in S1 to the methanol solution, mixing well, adding ammonium chloride, then adding formaldehyde dropwise, and reflux reaction to obtain a reaction solution; S3, the reaction solution obtained in S2 was concentrated to 10-15% of the original volume by rotary evaporation, the pH was adjusted to 9, the organic phase was extracted with dichloromethane, filtered, the solvent was evaporated, and dried to obtain the intermediate; S4, adding the intermediate obtained in S3 to hexadecane bromide, stirring in an oil bath under nitrogen protection, cooling, and drying to obtain a cationic long-chain monomer; The method for preparing the composite tackifier containing a sulfonic acid copolymer in the fracturing fluid specifically comprises the following steps: Acrylamide, acrylic acid, sodium 3-allyloxy-2-hydroxy-1-propane sulfonate and a cationic long-chain monomer are added to a reactor in sequence, followed by deionized water and Span-80, and the pH is adjusted to 10. Under nitrogen protection, 0.06-0.08% of ammonium persulfate by weight of the polymer monomer and 0.06-0.08% of sodium bisulfite by weight of the polymer monomer are added, and finally white oil is added, stirred evenly, and stirred in a water bath at 20-30°C at 60-80 rpm for 4 hours to obtain a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid.

2. The method for preparing a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid according to claim 1, characterized in that: In S1, the amount of 4-vinylaniline added to the methanol solution is 0.2-0.25 g / mL.

3. The method for preparing a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid according to claim 2, characterized in that: In S2, the amount of the mixed solution added to the methanol solution is 0.25-0.35 g / mL.

4. The method for preparing a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid according to claim 3, characterized in that: In S2, the reflux reaction temperature is 60-70°C and the time is 8-10 hours.

5. The method for preparing a composite tackifier containing a sulfonic acid group copolymer in a fracturing fluid according to claim 4, characterized in that: In S4, the oil bath is stirred at a temperature of 120-150° C., a speed of 50-60 rpm, and a time of 15-20 h.

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