Dimer acid type viscoelastic surfactant as well as preparation method and application thereof

Abstract

The invention relates to the technical field of surfactants, in particular to a dimer acid type viscoelastic surfactant as well as a preparation method and application thereof. The preparation method of the dimer acid type viscoelastic surfactant comprises the following steps: reacting dimer acid with N, N-dimethyl-1, 3-propane diamine under the catalysis of a catalyst to generate a dimer acid amide propyl dimethyl tertiary amine intermediate; the dimer acid amide propyl dimethyl tertiary amine intermediate and sodium chloroacetate are subjected to a reaction, and the dimer acid type viscoelastic surfactant is generated; the structure of the dimer acid is # imgabs0 #. The temperature resistance and the salt resistance of the dimer acid type viscoelastic surfactant prepared by the method disclosed by the invention are remarkably improved.

Description

Technical Field

[0001] The present application relates to a viscoelastic surfactant, and in particular to a preparation method and application of a dimer acid type viscoelastic surfactant. Background Art

[0002] my country's crude oil production is mainly shale oil. The primary oil production is produced by using the pressure of the oil and gas reservoir itself. The secondary oil production is produced by water injection displacement. The remaining oil is produced by injecting chemicals, which is called tertiary oil production. Tertiary oil production can further improve the reservoir production rate. The main method is to use physical pressure to create cracks in the reservoir, and inject fracturing fluid with proppants such as sand to prevent the cracks from closing, thereby increasing the crude oil conductivity of the tight reservoir and facilitating subsequent water drive oil production. Therefore, fracturing is a key link in the entire fracturing operation. Generally, the fracturing fluid is required to have high viscosity and high temperature resistance. Viscoelastic surfactants are an important type of fracturing fluid, which has the advantages of simple construction, low cost, and easy operation. It is widely used in tertiary oil production.

[0003] Viscoelastic surfactants form unique worm-like micelles in water. The micelles entangle with each other to increase the viscosity of their aqueous solutions, forming viscoelastic hydrogels, which have the functions of increasing the viscosity of injected water, carrying sand, and increasing the sweep rate of water flooding. However, viscoelastic surfactants have disadvantages in application, such as the viscosity of their aqueous solutions decreases with increasing temperature, and they are prone to form insoluble floccules when the mineralization degree is high due to poor salt resistance.

[0004] Therefore, providing a viscoelastic surfactant with excellent temperature and salt resistance is of great significance for improving the efficiency of tertiary oil recovery fracturing, reducing oil production costs, and facilitating further high-quality and high-efficiency development of oil and gas fields. Summary of the invention

[0005] The purpose of the present application is to provide a dimer acid type viscoelastic surfactant and its preparation method and application to address the shortcomings of the gemini viscoelastic surfactant in terms of its poor temperature and salt resistance. The embodiments of the present application are implemented in this way.

[0006] In order to achieve the above-mentioned object, the first aspect of the present application is a dimer acid type viscoelastic surfactant having the following structure:

[0007]

[0008] The second aspect of the present application provides a method for preparing a dimer acid-type viscoelastic surfactant, the method comprising:

[0009] The dimer acid reacts with N,N-dimethyl-1,3-propylenediamine under the catalysis of a catalyst to generate dimer acid amidopropyl dimethyl tertiary amine;

[0010] The dimer acid amide propyl dimethyl tertiary amine and sodium chloroacetate react to generate a dimer acid type viscoelastic surfactant, and the dimer acid type viscoelastic surfactant is a dimer acid type viscoelastic surfactant;

[0011] The structure of the dimer acid is

[0012] In some embodiments, the molar ratio of the dimer acid, N,N-dimethyl-1,3-propylenediamine and the sodium chloroacetate is 1:2-4:2-2.5.

[0013] In some embodiments, the catalyst is sodium hydroxide, potassium hydroxide or p-toluenesulfonic acid, and the mass of the catalyst is 0.1% to 0.2% of the sum of the mass of the dimer acid and N,N-dimethyl-1,3-propylenediamine.

[0014] In some embodiments, the reaction of dimer acid amidopropyl dimethyl tertiary amine and sodium chloroacetate comprises reacting the dimer acid amidopropyl dimethyl tertiary amine intermediate and sodium chloroacetate in an alcohol / water mixed solvent.

[0015] In some embodiments, the alcohol / water mixed solvent includes a methanol / water mixed solvent, an ethanol / water mixed solvent or an isopropanol / water mixed solvent, the mass ratio of alcohol to water is 1:1-3, and the mass of the alcohol / water mixed solvent is 55%-60% of the sum of the masses of dimer acid, N,N-dimethyl-1,3-propylenediamine and sodium chloroacetate.

[0016] In some embodiments, the reaction temperature of the dimer acid and N,N-dimethyl-1,3-propylenediamine under the catalysis of the catalyst is 130° C. to 160° C., and the reaction time is 6 h to 10 h;

[0017] The reaction temperature of the dimer acid amide propyl dimethyl tertiary amine intermediate and sodium chloroacetate is 70° C. to 80° C., and the reaction time is 6 h to 10 h.

[0018] In some embodiments, dimer acid reacts with N,N-dimethyl-1,3-propylenediamine under a catalyst to generate a dimer acid amidopropyl dimethyl tertiary amine intermediate, further comprising:

[0019] After the dimer acid and N,N-dimethyl-1,3-propylenediamine are reacted under the catalysis of a catalyst, deionized water is added, the mixture is fully stirred, and the aqueous phase is separated and removed. This is repeated at least three times to obtain the dimer acid amidopropyl dimethyl tertiary amine intermediate.

[0020] The third aspect of the present application provides an application of a dimer acid type viscoelastic surfactant, the application comprising:

[0021] The dimer acid type viscoelastic surfactant is mixed with ammonium chloride and water to prepare slippery water;

[0022] The slick water is mixed with sand to form a fracturing sand-carrying fluid;

[0023] The fracturing sand-carrying fluid is injected into the fracturing well for tertiary oil recovery.

[0024] In some embodiments, the mass ratio of the dimer acid type viscoelastic surfactant, ammonium chloride and water is 0.5-1:1-2:97-98; the mass ratio of the slippery water to sand is 60-70:30-40.

[0025] Beneficial effects of the present application: The hydrophobic long chains of the dimer acid type viscoelastic surfactant of the present application are connected by carbon-carbon covalent bonds, and two hydrophobic long-chain carboxylic acid structures are connected to form a dimer structure, so that the worm-like micelles formed by the molecules in water are arranged more closely due to the increase in molecular weight. When the temperature rises, the molecular diffusion movement is restricted due to the increase in molecular weight and the close arrangement between molecules, so the worm-like micelle structure can continue to be maintained. The macroscopic manifestation is that the viscosity decreases slowly with the increase in temperature, so that a certain viscosity can be maintained under relatively high temperature conditions. Furthermore, each dimer acid type viscoelastic surfactant molecule has two anionic hydrophilic groups and two cationic amphiphilic hydrophilic groups. The high density of the amphiphilic hydrophilic groups enables the micelles to remain stable under high mineralization conditions.

[0026] The preparation mechanism of the dimer acid type viscoelastic surfactant provided in the present application is clear, simple and easy to operate, and easy to expand production. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0028] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0029] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible sub-ranges and individual values ​​within the range (including integers and fractions).

[0030] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0031] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0032] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight.

[0033] The dimer acid type viscoelastic surfactant provided in the present application and its preparation method and application are further described below in conjunction with specific examples.

[0034] The present application first uses dimer acid and N,N-dimethyl-1,3-propylenediamine as raw materials, and reacts under the action of a catalyst to generate a dimer acid amidopropyl dimethyl tertiary amine intermediate. The reaction equation is as follows:

[0035]

[0036] Then, the dimer acid amide propyl dimethyl tertiary amine intermediate is reacted with sodium chloroacetate to generate a dimer acid type viscoelastic surfactant. The reaction equation is as follows:

[0037]

[0038] The molar ratio of the dimer acid, N,N-dimethyl-1,3-propylenediamine and the sodium chloroacetate is 1:2-4:2-2.5.

[0039] The catalyst is sodium hydroxide, potassium hydroxide or p-toluenesulfonic acid, and the mass of the catalyst is 0.1% to 0.2% of the sum of the mass of the dimer acid and N,N-dimethyl-1,3-propylenediamine.

[0040] The reaction of the dimer acid amidopropyl dimethyl tertiary amine intermediate and sodium chloroacetate comprises reacting the dimer acid amidopropyl dimethyl tertiary amine intermediate and sodium chloroacetate in an alcohol / water mixed solvent.

[0041] The alcohol / water mixed solvent includes a methanol / water mixed solvent, an ethanol / water mixed solvent or an isopropanol / water mixed solvent, the mass ratio of alcohol to water is 1:1-3, and the mass of the alcohol / water mixed solvent is 55%-60% of the sum of the masses of dimer acid, N,N-dimethyl-1,3-propylenediamine and sodium chloroacetate.

[0042] The reaction temperature of the dimer acid and N,N-dimethyl-1,3-propylenediamine under the catalysis of the catalyst is 130°C to 160°C, and the reaction time is 6h to 10h;

[0043] The reaction temperature of the dimer acid amide propyl dimethyl tertiary amine intermediate and sodium chloroacetate is 70° C. to 80° C., and the reaction time is 6 h to 10 h.

[0044] In some embodiments, dimer acid reacts with N,N-dimethyl-1,3-propylenediamine under a catalyst to generate a dimer acid amidopropyl dimethyl tertiary amine intermediate, further comprising:

[0045] After the dimer acid and N,N-dimethyl-1,3-propylenediamine are reacted under the catalysis of a catalyst, deionized water is added, the mixture is fully stirred, and the aqueous phase is separated and removed. This is repeated at least three times to obtain the dimer acid amidopropyl dimethyl tertiary amine intermediate.

[0046] The preparation of the dimer acid type viscoelastic surfactant is further described in conjunction with the following examples.

[0047] Example 1

[0048] Add dimer acid (280g, 0.5mol, Wuhan Kemi Biopharmaceutical Technology Co., Ltd., the dimer acid used in the following examples was purchased from this company), N, N-dimethyl-1,3-propylenediamine (112.2g, 1.1mol), potassium hydroxide (0.39g, 0.1%) to a 2L stainless steel reactor, react at 150°C and 0.5MPa for 6h, add deionized water, stir well, separate and remove the water phase, repeat three times to obtain a dimer acid amidopropyl dimethyl tertiary amine intermediate. Then add all the intermediates, ethanol / water mixed solvent (ethanol: water mass ratio is 1:1, a total of 720.75g), sodium chloroacetate (116.5g, 1mol) to a glass reactor, react at 80°C for 6h, and prepare a dimer acid type viscoelastic surfactant.

[0049] Example 2

[0050] Add dimer acid (280g, 0.5mol), N,N-dimethyl-1,3-propylenediamine (122.4g, 1.2mol), p-toluenesulfonic acid (0.40g, 0.1%) to a 2L stainless steel reactor, react at 150°C and 0.5MPa for 8h, add deionized water, stir well, separate and remove the water phase, repeat three times to obtain a dimer acid amidopropyl dimethyl tertiary amine intermediate. Then add all the intermediates to a glass reactor, add ethanol / water mixed solvent (methanol: water = 1:2, a total of 697.45g), sodium chloroacetate (139.8g, 1.2mol), react at 70°C for 10h, and prepare a dimer acid type viscoelastic surfactant.

[0051] Example 3

[0052] Add dimer acid (280g, 0.5mol), N,N-dimethyl-1,3-propylenediamine (153g, 1.5mol), p-toluenesulfonic acid (0.43g, 0.1%) to a 2L stainless steel reactor, react at 130°C for 10h, add deionized water, stir well, separate and remove the aqueous phase, repeat three times to obtain a dimer acid amidopropyl dimethyl tertiary amine intermediate. Then add all the intermediates to a glass reactor, add ethanol / water mixed solvent (methanol: water = 1:1, a total of 691.65g), sodium chloroacetate (145.6g, 1.25mol), react at 80°C for 8h, and prepare a dimer acid type viscoelastic surfactant.

[0053] Example 4

[0054] Add dimer acid (280g, 0.5mol), N,N-dimethyl-1,3-propylenediamine (204g, 2mol), potassium hydroxide (0.73g, 0.15%) to a 2L stainless steel reactor, react at 160°C and 0.5MPa for 6h, add deionized water, stir well, separate and remove the water phase, repeat three times to obtain a dimer acid amidopropyl dimethyl tertiary amine intermediate. Then add all the intermediates to a glass reactor, add isopropanol / water mixed solvent (isopropanol: water = 1:1, a total of 709.05g), sodium chloroacetate (128.2g, 1.1mol), react at 75°C for 10h, and prepare a dimer acid type viscoelastic surfactant.

[0055] Example 5

[0056] Add dimer acid (280g, 0.5mol), N,N-dimethyl-1,3-propylenediamine (132.6g, 1.3mol), sodium hydroxide (0.62g, 0.15%) to a 2L stainless steel reactor, react at 160°C and 0.5MPa for 8h, add deionized water, stir well, separate and remove the water phase, repeat three times to obtain a dimer acid amidopropyl dimethyl tertiary amine intermediate. Then add all the intermediates to a glass reactor, add ethanol / water mixed solvent (ethanol: water = 1:2, a total of 697.45g), sodium chloroacetate (139.8g, 1.2mol), react at 80°C for 10h, and prepare a dimer acid type viscoelastic surfactant.

[0057] Example 6

[0058] Add dimer acid (280g, 0.5mol), N,N-dimethyl-1,3-propylenediamine (122.4g, 1.2mol), sodium hydroxide (0.80g, 0.2%) to a 2L stainless steel reactor, react at 140°C and 0.5MPa for 10h, add deionized water, stir well, separate and remove the water phase, repeat three times to obtain a dimer acid amidopropyl dimethyl tertiary amine intermediate. Then add all the intermediates to a glass reactor, add ethanol / water mixed solvent (ethanol: water = 1:3, a total of 720.75g), sodium chloroacetate (116.5g, 1mol), react at 80°C for 6h, and prepare a dimer acid type viscoelastic surfactant.

[0059] The present application also provides an application of a dimer acid type viscoelastic surfactant, the application comprising:

[0060] The dimer acid type viscoelastic surfactant is mixed with ammonium chloride and water to prepare slippery water;

[0061] The slick water is mixed with sand to form a fracturing sand-carrying fluid;

[0062] The fracturing sand-carrying fluid is injected into the fracturing well for tertiary oil recovery.

[0063] In some embodiments, the mass ratio of the dimer acid type viscoelastic surfactant, ammonium chloride and water is 0.5-1:1-2:97-98; the mass ratio of the slippery water to sand is 60-70:30-40.

[0064] According to the ratio requirements for tertiary oil recovery, the dimer acid type viscoelastic surfactant prepared in Example 2 was added with water and ammonium chloride to prepare a solution, in which the mass ratio of the dimer acid type viscoelastic surfactant, ammonium chloride and water was 1:1:98.

[0065] The present application also provides a comparative example, in which oleamidopropyl betaine (Shengci (Hubei) Industrial Materials Co., Ltd., model OAB-30) is added to water and ammonium chloride to prepare a comparative solution, and the mass ratio of oleamidopropyl betaine, water and ammonium chloride in the comparative solution is 1:1:98. The following characterizes the temperature resistance and salt resistance of the dimer acid type viscoelastic surfactant and the comparative example by measuring the viscosity change of the solution under different conditions. The instrument used for testing the viscosity is a six-speed viscometer.

[0066] The temperature resistance of the solution of the present application and the comparative solution was characterized by the viscosity changes at different temperatures. The measurement results are shown in Table 1.

[0067] Table 1 Temperature resistance test results

[0068]

[0069] The solution of the present application and the reference solution were added to clean water, a standard salt solution with a mineralization degree of 20,000 (sodium chloride, calcium chloride and magnesium chloride) and a standard salt solution with a mineralization degree of 50,000, respectively, and the salt resistance of the two was characterized by the change in viscosity. The temperature during the test was 25 degrees Celsius. The measurement results are shown in Table 2.

[0070] Table 2 Salt tolerance test results

[0071]

[0072] According to the above measurement results and in combination with the molecular structure of the two surfactants, the oleamidopropyl betaine used in the comparative example forms worm-like micelles by self-assembly in water, and its aqueous solution has a certain viscosity, but as the temperature rises, the worm-like micelles are destroyed, so the viscosity of its aqueous solution decreases rapidly. The dimer acid type surfactant of the present application is connected by carbon-carbon covalent bonds because its hydrophobic long chain is increased in molecular weight and the hydrophobic long chains in each molecule and the hydrophobic long chains of adjacent molecules are arranged more closely. When the temperature rises, the molecular diffusion movement is restricted due to the increase in molecular weight and the close arrangement between molecules, so the worm-like micelle structure can continue to be maintained. The macroscopic performance is that the viscosity decreases slowly with the increase in temperature, so that a certain viscosity can be maintained under relatively high temperature conditions, and each dimer acid type surfactant molecule has two anionic hydrophilic groups and two cationic amphiphilic groups, and the density of the amphiphilic groups is large so that the micelles still maintain stability under high mineralization conditions.

[0073] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A dimer acid type viscoelastic surfactant, characterized in that: It has the following structure:

2. A method for preparing a dimer acid type viscoelastic surfactant, characterized in that: The method comprises: The dimer acid reacts with N,N-dimethyl-1,3-propylenediamine under the catalysis of a catalyst to generate a dimer acid amidopropyl dimethyl tertiary amine intermediate; The dimer acid amide propyl dimethyl tertiary amine intermediate reacts with sodium chloroacetate to generate a dimer acid type viscoelastic surfactant, and the dimer acid type viscoelastic surfactant is a dimer acid type viscoelastic surfactant; The structure of the dimer acid is 3. The method for preparing the dimer acid type viscoelastic surfactant according to claim 2, characterized in that: The molar ratio of the dimer acid, N,N-dimethyl-1,3-propylenediamine and the sodium chloroacetate is 1:2-4:2-2.

5.

4. The method for preparing the dimer acid type viscoelastic surfactant according to claim 2, characterized in that: The catalyst is sodium hydroxide, potassium hydroxide or p-toluenesulfonic acid, and the mass of the catalyst is 0.1% to 0.2% of the sum of the mass of the dimer acid and N,N-dimethyl-1,3-propylenediamine.

5. The method for preparing the dimer acid type viscoelastic surfactant according to claim 2, characterized in that: The reaction of the dimer acid amidopropyl dimethyl tertiary amine intermediate and sodium chloroacetate comprises reacting the dimer acid amidopropyl dimethyl tertiary amine intermediate and sodium chloroacetate in an alcohol / water mixed solvent.

6. The method for preparing the dimer acid type viscoelastic surfactant according to claim 5, characterized in that: The alcohol / water mixed solvent includes a methanol / water mixed solvent, an ethanol / water mixed solvent or an isopropanol / water mixed solvent, the mass ratio of alcohol to water is 1:1-3, and the mass of the alcohol / water mixed solvent is 55%-60% of the sum of the masses of dimer acid, N,N-dimethyl-1,3-propylenediamine and sodium chloroacetate.

7. The method for preparing the dimer acid type viscoelastic surfactant according to claim 2, characterized in that: The reaction temperature of the dimer acid and N,N-dimethyl-1,3-propylenediamine under the catalysis of the catalyst is 130°C to 160°C, and the reaction time is 6h to 10h; The reaction temperature of the reaction between dimer acid amide propyl dimethyl tertiary amine and sodium chloroacetate is 70° C. to 80° C., and the reaction time is 6 h to 10 h.

8. The method for preparing the dimer acid type viscoelastic surfactant according to claim 2, characterized in that: The dimer acid reacts with N,N-dimethyl-1,3-propylenediamine under the catalysis of a catalyst to generate dimer acid amidopropyl dimethyl tertiary amine, including: After the dimer acid and N,N-dimethyl-1,3-propylenediamine are reacted under the catalysis of a catalyst, deionized water is added, the mixture is fully stirred, and the aqueous phase is separated and removed and the process is repeated at least three times to obtain the dimer acid amidopropyl dimethyl tertiary amine.

9. An application of a dimer acid type viscoelastic surfactant, characterized in that: The applications include: The dimer acid type viscoelastic surfactant is mixed with ammonium chloride and water to prepare slippery water; The slick water is mixed with sand to form a fracturing sand-carrying fluid; The fracturing sand-carrying fluid is injected into the fracturing well to perform tertiary oil recovery.

10. The use of the dimer acid type viscoelastic surfactant according to claim 9, characterized in that: The mass ratio of the dimer acid type viscoelastic surfactant, ammonium chloride and water is 0.5-1:1-2:97-98; the mass ratio of the slippery water to sand is 60-70:30-40.

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