Fracturing fluid thickening agent and preparation method thereof

Abstract

The invention relates to the technical field of thickening agents, and discloses a fracturing fluid thickening agent and a preparation method thereof.The preparation method comprises the steps that dehydroabietic acid is added into thionyl chloride to prepare dehydroabietic acid acyl chloride; the preparation method comprises the following steps: adding dehydroabietic acid acyl chloride into 2-aminoterephthalic acid to obtain an intermediate A; reacting the intermediate A to obtain modified acrylamide; dissolving modified acrylamide, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and dimethyl diallyl ammonium chloride in deionized water, and adding the solution into the oil phase to obtain a mixed solution; adding acrylic acid into the mixed solution, and adjusting the pH value of the solution; and continuing to introduce nitrogen, adding an initiator, and carrying out heating reaction to obtain the fracturing fluid thickening agent. Through a rigid dehydroabietic acid phenanthrene ring structure, a multifunctional amide structure and a double-bond structure, the polymerization of a polymer and the formation of hydrogen bonds in a compound are further enhanced, and the heat resistance and the sand-carrying capacity of the fracturing fluid thickening agent are further improved.

Description

Technical Field

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

[0002] Fracturing fluid thickeners are important chemical additives used in oil and gas well fracturing operations. Their main function is to increase the viscosity of the fracturing fluid, thereby improving the sand-carrying capacity, reducing filtration loss, increasing the fracture width, and ultimately achieving the characteristics of increasing oil and gas production and injection. Although traditional acrylamide-based fracturing fluid thickeners have good thickening performance, their heat resistance and salt tolerance are poor, which limits their application in high-temperature and high-salinity reservoirs. The research direction of fracturing fluid thickeners mainly focuses on improving temperature and salt tolerance, reducing residue, and enhancing environmental friendliness.

[0003] The patent with the publication number CN113214817 A discloses a super-high-temperature fracturing fluid thickener and a preparation method thereof, including: taking acrylamide, acrylic acid, and a rigid monomer, and adding them into deionized water to obtain a mixed solution; heating the mixed solution to 45 - 60 °C, adding an initiator, and carrying out a polymerization reaction under insulation for 6 - 8 h to obtain a solidified copolymer; cutting, drying, and pulverizing the obtained copolymer to obtain the thickener. Although the fracturing fluid thickener obtained by this invention has a relatively high viscosity and good stability at high temperatures, it still uses petroleum-based compounds as the main raw materials and does not have environmental friendliness. The patent with the publication number CN118146446 A discloses a fracturing fluid thickener and a preparation method thereof, including: under nitrogen conditions, uniformly stirring white oil and an emulsifier to obtain an oil phase; dissolving α-eleostearic acid in a solvent, adding thionyl chloride to prepare α-eleostearoyl chloride, and introducing ammonia gas for reaction to obtain α-eleostearamide; adding α-eleostearamide, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and dimethyldiallylammonium chloride into the oil phase to obtain a mixed solution; adding acrylic acid to the mixed solution and adjusting the pH of the solution; continuously introducing nitrogen gas, adding an initiator, and carrying out a temperature-raising reaction to obtain the fracturing fluid thickener. Although this invention modifies the temperature and salt tolerance of the fracturing fluid thickener by adding a natural modified derivative, α-eleostearamide, and has environmental friendliness, α-eleostearamide belongs to a mono-functional amide structure and still has certain limitations in the temperature resistance and sand-carrying capacity of the modified fracturing fluid thickener. Therefore, it is an urgent problem to develop a fracturing fluid thickener that meets environmental protection requirements and can be used at high temperatures. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the shortcoming of poor temperature resistance of the fracturing fluid thickener in the prior art, so as to provide a fracturing fluid thickener and a preparation method thereof. Using natural rosin derivative dehydroabietic acid as a raw material, modified acrylamide is obtained, and a fracturing fluid thickener is obtained, improving the temperature resistance performance and sand-carrying capacity of the fracturing fluid thickener.

[0005] To solve the above technical problem, the present invention provides a preparation method of a fracturing fluid thickener, including the following steps: (1) Dissolve dehydroabietic acid in a first solvent, and add thionyl chloride to prepare dehydroabietic acid acyl chloride; (2) Dissolve dehydroabietic acid acyl chloride in a second solvent, add 2-aminoterephthalic acid, and keep the pH value at 7.5 - 9 during the reaction to obtain intermediate A; (3) Dissolve intermediate A in a third solvent, add allylamine and an activator, and obtain modified acrylamide after the reaction; (4) Under nitrogen conditions, stir white oil and an emulsifier evenly to obtain an oil phase; (5) Dissolve modified acrylamide, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and dimethyldiallylammonium chloride in deionized water, and add them to the oil phase to obtain a mixed solution; (6) Add acrylic acid to the mixed solution and adjust the pH of the solution; (7) Continue to introduce nitrogen, add an initiator, and after heating and reacting, obtain a fracturing fluid thickener.

[0006] Preferably, the preparation process of the modified acrylamide is: .

[0007] Preferably, the first solvent in step (1) is at least one of dichloromethane or tetrahydrofuran, the molar ratio of dehydroabietic acid to thionyl chloride is 1:1 - 1:2, the reaction temperature is 0 - 20°C, and the reaction time is 4 - 8 h.

[0008] Preferably, the second solvent in step (2) is at least one of dichloromethane or tetrahydrofuran, the molar ratio of dehydroabietic acid acyl chloride to 2-aminoterephthalic acid is 1:1 - 1:1.2, the reaction temperature is 10 - 20°C, and the reaction time is 2 - 4 h.

[0009] Preferably, the third solvent in step (3) is at least one of dichloromethane or N,N-dimethylformamide (DMF), the activator is 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC), the molar ratio of intermediate A to allylamine is 1:2 - 1:3, the reaction temperature is 50 - 100°C, and the reaction time is 4 - 8 h.

[0010] Preferably, the weight ratio of the modified acrylamide, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and dimethyldiallylammonium chloride is 1-5:5-10:1-5:1-3; the weight ratio of acrylic acid to acrylamide is 1:3-1:5; and the pH is 7-8.

[0011] Preferably, the reaction temperature in step (7) is 50-80 °C, and the reaction time is 2-6 h.

[0012] Preferably, the emulsifier is at least one of Span 80, polyoxyethylene octylphenol ether 10, or fatty alcohol polyoxyethylene ether AEO-5.

[0013] Preferably, the initiator includes ammonium persulfate, sodium bisulfite, and azobisisobutyronitrile, and the mass ratio of ammonium persulfate, sodium bisulfite, and azobisisobutyronitrile is 1-2:1-2:1.

[0014] Meanwhile, the present invention also provides a fracturing fluid thickener prepared by the above preparation method.

[0015] The technical solution of the present invention has the following advantages: A fracturing fluid thickener and a preparation method thereof provided by the present invention use natural rosin derivative dehydroabietic acid as a raw material to obtain a modified acrylamide through modification, and obtain a fracturing fluid thickener; the rigid phenanthrene ring structure of dehydroabietic acid, the multifunctional amide structure, and the double bond structure further strengthen the polymerization of the polymer and the formation of intra-molecular hydrogen bonds, further improving the heat resistance of the fracturing fluid thickener and enabling it to still have a high viscosity at high temperatures, increasing the intermolecular force, and enhancing the sand-carrying capacity. Description of the Drawings

[0016] Figure 1 is the FT-IR diagram of the modified acrylamide. Detailed Embodiments

[0017] The following embodiments are provided to better further understand the present invention, which are not limited to the best implementation mode, do not limit the content and protection scope of the present invention, and any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior art features falls within the protection scope of the present invention.

[0018] For those not specifying specific experimental steps or conditions in the embodiments, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For the reagents or instruments not specifying the manufacturer, they are all conventional reagent products that can be obtained through commercial purchase.

[0019] FT-IR (Fourier transform infrared spectroscopy) uses a Nicolet IS50 infrared spectrometer.

[0020] Example 1: A preparation method of a fracturing fluid thickening agent, comprising the following steps: (1) Dissolve 30 g of dehydroabietic acid in 300 mL of dichloromethane, add 18 g of thionyl chloride at 0 °C, and prepare dehydroabietic acid acyl chloride at 10 °C for 6 h; (2) Dissolve 32 g of dehydroabietic acid acyl chloride in 300 mL of dichloromethane, add 18 g of 2-aminoterephthalic acid, maintain the pH value at 7.5 - 9 during the reaction, and obtain intermediate A at 15 °C for 3 h; (3) Dissolve 46 g of intermediate A in 500 mL of DMF, add 12 g of allylamine and 19 g of activator, and obtain modified acrylamide after reaction; (4) Under nitrogen conditions, stir 100 g of white oil and 10 g of span 80 evenly to obtain an oil phase; (5) Dissolve 50 g of modified acrylamide, 70 g of acrylamide, 10 g of 2-acrylamido-2-methylpropanesulfonic acid, and 5 g of dimethyldiallylammonium chloride in 200 g of deionized water, and add them to the oil phase to obtain a mixed solution; (6) Add 20 g of acrylic acid to the mixed solution and adjust the pH of the solution to 7; (7) Continue to pass nitrogen, stir for 30 min, add 0.4 g of ammonium persulfate, 0.2 g of sodium bisulfite, and 0.2 g of azobisisobutyronitrile, heat up to 60 °C and react for 4 h to obtain a fracturing fluid thickening agent.

[0021] The FT-IR diagram of the obtained modified acrylamide is as follows Figure 1 shown, from Figure 1 it can be seen that at 3267.41 cm -1 there appears a characteristic absorption peak of N-H, at 3080.73 cm -1 there appears a characteristic absorption peak of terminal =C-H, at 1656.53 cm -1 there appears a characteristic absorption peak of carbonyl group, and at 1623.16 cm -1 there appears a characteristic absorption peak of carbon-carbon double bond.

[0022] Example 2: A preparation method of a fracturing fluid thickening agent, comprising the following steps: (1) Dissolve 30 g of dehydroabietic acid in 300 mL of dichloromethane, add 24 g of thionyl chloride at 0 °C, and prepare dehydroabietic acid acyl chloride at 20 °C for 8 h; (2) Dissolve 32 g of dehydroabietic acid acyl chloride in 300 mL of dichloromethane, add 21 g of 2-aminoterephthalic acid, maintain the pH value at 7.5 - 9 during the reaction, and obtain intermediate A at 20 °C for 4 h; (3) Dissolve 46 g of intermediate A in 500 mL of DMF, add 17 g of allylamine and 19 g of activator, and obtain modified acrylamide after reaction; (4) Under nitrogen condition, stir 100 g of white oil and 10 g of polyoxyethylene octylphenol ether 10 evenly to obtain an oil phase; (5) Dissolve 30 g of modified acrylamide, 100 g of acrylamide, 20 g of 2-acrylamido-2-methylpropanesulfonic acid and 5 g of dimethyldiallylammonium chloride in 200 g of deionized water, and add them to the oil phase to obtain a mixed solution; (6) Add 20 g of acrylic acid to the mixed solution and adjust the pH of the solution to 7; (7) Continue to pass nitrogen, stir for 30 min, add 0.3 g of ammonium persulfate, 0.3 g of sodium bisulfite and 0.3 g of azobisisobutyronitrile, heat up to 80 °C and react for 6 h to obtain a thickening agent for fracturing fluid.

[0023] Example 3: A preparation method of a thickening agent for fracturing fluid, comprising the following steps: (1) Dissolve 30 g of dehydroabietic acid in 300 mL of dichloromethane, add 12 g of thionyl chloride at 0 °C, and prepare dehydroabietic acid acyl chloride at 0 °C for 4 h; (2) Dissolve 32 g of dehydroabietic acid acyl chloride in 300 mL of dichloromethane, add 18 g of 2-aminoterephthalic acid, keep the pH value at 7.5 - 9 during the reaction, and obtain intermediate A at 10 °C for 2 h; (3) Dissolve 46 g of intermediate A in 500 mL of DMF, add 12 g of allylamine and 19 g of activator, and obtain modified acrylamide after reaction; (4) Under nitrogen condition, stir 100 g of white oil and 10 g of fatty alcohol polyoxyethylene ether AEO-5 evenly to obtain an oil phase; (5) Dissolve 10 g of modified acrylamide, 50 g of acrylamide, 10 g of 2-acrylamido-2-methylpropanesulfonic acid and 10 g of dimethyldiallylammonium chloride in 200 g of deionized water, and add them to the oil phase to obtain a mixed solution; (6) Add 17 g of acrylic acid to the mixed solution and adjust the pH of the solution to 8; (7) Continue to pass nitrogen, stir for 30 min, add 0.2 g of ammonium persulfate, 0.4 g of sodium bisulfite and 0.2 g of azobisisobutyronitrile, heat up to 50 °C and react for 2 h to obtain a thickening agent for fracturing fluid.

[0024] Example 4: A preparation method of a thickening agent for fracturing fluid, comprising the following steps: (1) Dissolve 30 g of dehydroabietic acid in 300 mL of dichloromethane, add 18 g of thionyl chloride at 0 °C, and prepare dehydroabietic acid acyl chloride at 10 °C for 6 h; (2) Dissolve 32 g of dehydroabietic acid acyl chloride in 300 mL of dichloromethane, add 18 g of 2-aminoterephthalic acid, maintain the pH value at 7.5 - 9 during the reaction, and obtain intermediate A at 15 °C for 3 h; (3) Dissolve 46 g of intermediate A in 500 mL of DMF, add 12 g of allylamine and 19 g of activator, and obtain modified acrylamide after the reaction; (4) Under nitrogen condition, stir 100 g of white oil and 10 g of Span 80 evenly to obtain an oil phase; (5) Dissolve 10 g of modified acrylamide, 70 g of acrylamide, 10 g of 2-acrylamido-2-methylpropanesulfonic acid, and 5 g of dimethyldiallylammonium chloride in 200 g of deionized water, and add it to the oil phase to obtain a mixed solution; (6) Add 20 g of acrylic acid to the mixed solution and adjust the solution pH to 7; (7) Continue to pass nitrogen, stir for 30 min, add 0.4 g of ammonium persulfate, 0.2 g of sodium bisulfite, and 0.2 g of azobisisobutyronitrile, heat up to 60 °C and react for 4 h to obtain a fracturing fluid thickening agent.

[0025] Example 5: A preparation method of a fracturing fluid thickening agent, comprising the following steps: (1) Dissolve 30 g of dehydroabietic acid in 300 mL of dichloromethane, add 24 g of thionyl chloride at 0 °C, and prepare dehydroabietic acid acyl chloride at 20 °C for 8 h; (2) Dissolve 32 g of dehydroabietic acid acyl chloride in 300 mL of dichloromethane, add 21 g of 2-aminoterephthalic acid, maintain the pH value at 7.5 - 9 during the reaction, and obtain intermediate A at 20 °C for 4 h; (3) Dissolve 46 g of intermediate A in 500 mL of DMF, add 17 g of allylamine and 19 g of activator, and obtain modified acrylamide after the reaction; (4) Under nitrogen condition, stir 100 g of white oil and 10 g of polyoxyethylene octylphenol ether 10 evenly to obtain an oil phase; (5) Dissolve 10 g of modified acrylamide, 100 g of acrylamide, 20 g of 2-acrylamido-2-methylpropanesulfonic acid, and 5 g of dimethyldiallylammonium chloride in 200 g of deionized water, and add it to the oil phase to obtain a mixed solution; (6) Add 20 g of acrylic acid to the mixed solution and adjust the solution pH to 7; (7) Continuously introduce nitrogen gas and stir for 30 min. Then add 0.3 g of ammonium persulfate, 0.3 g of sodium bisulfite, and 0.3 g of azobisisobutyronitrile, and raise the temperature to 80 °C for reaction for 6 h to obtain a fracturing fluid thickening agent.

[0026] Comparative Example 1: A preparation method of a fracturing fluid thickening agent, comprising the following steps: (1) Under nitrogen gas conditions, uniformly stir 100 g of white oil and 10 g of span 80 to obtain an oil phase; (2) Dissolve 70 g of acrylamide, 10 g of 2-acrylamido-2-methylpropanesulfonic acid, and 5 g of dimethyldiallylammonium chloride in 50 g of deionized water, and add it to the oil phase to obtain a mixed solution; (3) Add 20 g of acrylic acid to the mixed solution and adjust the pH of the solution to 7; (4) Continuously introduce nitrogen gas, stir for 30 min, add 0.4 g of ammonium persulfate, 0.2 g of sodium bisulfite, and 0.2 g of azobisisobutyronitrile, and raise the temperature to 60 °C for reaction for 4 h to obtain a fracturing fluid thickening agent.

[0027] Comparative Example 2: The fracturing fluid thickening agent prepared according to Example 1 in a patent disclosed in Patent Publication No. CN118146446 A and its preparation method.

[0028] The fracturing fluid thickening agents prepared in Examples 1 to 5 and Comparative Examples 1 and 2 were respectively dissolved in tap water at a concentration of 0.6%, and at different temperatures, shear viscosity tests were carried out at a shear rate of 170 S -1 for 2 h, and the test results are shown in Table 1.

[0029] Table 1 Viscosities of fracturing fluid thickening agents obtained in different examples and comparative examples at different temperatures in tap water

[0030] The fracturing fluid thickening agents prepared in Examples 1 to 5 and Comparative Examples 1 and 2 were respectively dissolved in 85,000 salinity brine at a concentration of 1.4%, and at 120 °C and 170 S -1 shear viscosity tests were carried out for 2 h, and the test results are shown in Table 2.

[0031] Table 2 Viscosities of fracturing fluid thickening agents obtained in different examples and comparative examples in 85,000 salinity brine

[0032] Take the fracturing fluid thickening agents prepared in Examples 1 to 5 and Comparative Examples 1 and 2 and dissolve them in tap water at a concentration of 0.6%, and at 60 °C and 170 S -1100 g of the dissolved sample after viscosity testing by shearing at a shearing speed for 2 h was added with 25 g of quartz sand (particle size: 40 - 70 mesh). After stirring evenly, it was poured into a graduated cylinder and allowed to stand for observation. The settling velocity of the sand in the fracturing fluid was measured by the static suspension method to evaluate its sand-carrying performance.

[0033] Table 3 Settling Velocity of the Fracturing Fluid Thickener Obtained from Different Examples and Comparative Examples

[0034] As can be seen from Tables 1 - 3, the addition of modified acrylamide not only significantly increases the viscosity of the fracturing fluid thickener at different temperatures, but also improves the salt tolerance and sand-carrying ability of the fracturing fluid thickener. This is because the rigid phenanthrene ring structure of dehydroabietic acid, the multi-functional amide structure, and the double bond structure further strengthen the polymerization of the polymer and the formation of intramolecular hydrogen bonds, further improving the heat resistance of the fracturing fluid thickener and enabling it to still have a high viscosity at high temperatures, increasing the intermolecular force and enhancing the sand-carrying ability.

[0035] Obviously, the above examples are only for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A preparation method of a fracturing fluid thickening agent, characterized in that, It includes the following steps: (1) Dissolve dehydroabietic acid in a first solvent, and add thionyl chloride to prepare dehydroabietic acid acyl chloride; (2) Dissolve dehydroabietic acid acyl chloride in a second solvent, add 2-aminoterephthalic acid, and keep the pH value of the reaction at 7.5 - 9 to obtain intermediate A; (3) Dissolve intermediate A in a third solvent, add allylamine and an activator, and obtain modified acrylamide after reaction; (4) Under nitrogen conditions, stir white oil and an emulsifier evenly to obtain an oil phase; (5) Dissolve modified acrylamide, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and dimethyldiallylammonium chloride in deionized water, and add them to the oil phase to obtain a mixed solution; (6) Add acrylic acid to the mixed solution and adjust the pH of the solution; (7) Continue to introduce nitrogen, add an initiator, and after heating and reacting, obtain a fracturing fluid thickening agent; The first solvent is at least one of dichloromethane or tetrahydrofuran, the second solvent is at least one of dichloromethane or tetrahydrofuran, the third solvent is at least one of dichloromethane or N,N-dimethylformamide, and the activator is 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride; The weight ratio of the modified acrylamide, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and dimethyldiallylammonium chloride is 1 - 5:5 - 10:1 - 5:1 - 3; the weight ratio of acrylic acid to acrylamide is 1:3 - 1:

5.

2. The preparation method of the fracturing fluid thickener according to claim 1, characterized in that, In step (1), the molar ratio of dehydroabietic acid to thionyl chloride is 1:1 - 1:2, the reaction temperature is 0 - 20°C, and the reaction time is 4 - 8 h.

3. The preparation method of the fracturing fluid thickener according to claim 1, characterized in that, In step (2), the molar ratio of dehydroabietic acid acyl chloride to 2-aminoterephthalic acid is 1:1 - 1:1.2, the reaction temperature is 10 - 20°C, and the reaction time is 2 - 4 h.

4. The preparation method of the fracturing fluid thickening agent according to claim 1, characterized in that, In step (3), the molar ratio of intermediate A to allylamine is 1:2 - 1:3, the reaction temperature is 50 - 100°C, and the reaction time is 4 - 8 h.

5. The preparation method of the fracturing fluid thickening agent according to claim 1, wherein The pH is 7 - 8.

6. The preparation method of the fracturing fluid thickening agent according to claim 1, characterized in that, In step (7), the reaction temperature is 50 - 80°C, and the reaction time is 2 - 6 h.

7. The preparation method of the fracturing fluid thickener according to claim 1, characterized in that, The emulsifier is at least one of Span 80, polyoxyethylene octylphenol ether 10, or fatty alcohol polyoxyethylene ether AEO-5.

8. The preparation method of the fracturing fluid thickening agent according to claim 1, wherein The initiator includes ammonium persulfate, sodium bisulfite, and azobisisobutyronitrile, and the mass ratio of ammonium persulfate, sodium bisulfite, and azobisisobutyronitrile is 1 - 2:1 - 2:

1.

9. A fracturing fluid thickening agent, characterized in that, It is prepared by using the preparation method described in any one of claims 1 - 8.

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