Diester single-tail cationic surfactant as well as preparation method and application thereof

Abstract

The invention relates to the technical field of oilfield chemistry, in particular to a diester single-tail cationic surfactant, a preparation method and application thereof and a discharge aiding agent for acid fracturing. The diester single-tail cationic surface active agent is prepared from raw materials such as N, N-dimethyl-1, 3amine, methyl acrylate and halogenated alkane. The invention provides a low-cost, green and environment-friendly diester single-tail cationic surface active agent, and the preparation method of the diester single-tail cationic surface active agent is simple and convenient to operate, safe, reliable and beneficial to industrial production, popularization and application, and has a wide market prospect. The acid fracturing discharge aiding agent using the diester single-tailed surfactant as a raw material can effectively reduce the surface and interfacial tension of an aqueous solution, and meets the technical specification of the acid fracturing discharge aiding agent.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemistry, and is a diester single-tail cationic surfactant, a preparation method and application thereof, and a drainage aid for acid fracturing. Background Art

[0002] Acid fracturing transformation technology is an important measure for the efficient development of oil and gas fields. It is the main technical means to achieve the exploration and development of unconventional oil and gas resources, increase and stabilize the production of conventional oil and gas fields, and improve the effect of reservoir transformation. In the process of acid fracturing, it is usually necessary to rely on the formation pressure to quickly discharge the return fluid in the well to the ground. When the formation pressure gradually decreases, the return rate decreases significantly, and the residue in the return fluid will cause blockage after precipitation, resulting in secondary pollution of the formation, which seriously affects the construction efficiency and the effect of acid fracturing transformation. In order to solve the problem of difficulty in returning the return fluid after oil acid fracturing, the use of drainage aids is a conventional method.

[0003] A drainage aid is a type of fracturing fluid additive that can effectively reduce surface tension and interfacial tension, reduce capillary resistance, increase flowback rate and flowback ratio, and thus reduce formation damage. Although there are many drainage aid systems reported and used at home and abroad, most of them are prepared by compounding fluorocarbon surfactants with other surfactants. Fluorocarbon surfactants have high surface activity and can reduce surface tension to 23mN / m. However, they are expensive, difficult to degrade, and have high biological toxicity. In view of this, the development of low-cost, green and environmentally friendly drainage aid systems has become an urgent problem to be solved. Summary of the invention

[0004] The present invention provides a diester single-tail cationic surfactant, which overcomes the deficiencies of the prior art and can effectively solve the problems of high price and poor environmental performance of the existing surfactants for fracturing fluids.

[0005] One of the technical solutions of the present invention is achieved by the following measures: a diester single-tail cationic surfactant, the chemical structural formula of which is:

[0006]

[0007] Where R is C 12 To C 16 An aliphatic hydrocarbon group, X is chlorine or bromine.

[0008] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions:

[0009] The above diester single-tail surfactant is prepared according to the following steps:

[0010] In the first step, N,N-dimethyl-1,3-amine is dissolved in anhydrous ethanol in a reactor, stirred evenly, the temperature of the reactor is lowered to 0 to 5°C, methyl acrylate is added dropwise, and after the addition is completed, the reaction is continued at room temperature for 20 to 26 hours;

[0011] In the second step, halogenated alkane is added to the reactor, stirred evenly, and refluxed to react. After the reaction is completed, the reaction product is concentrated and the solvent is removed. The reaction product is then recrystallized with ethyl acetate to obtain a viscous liquid diester single-tail cationic surfactant.

[0012] In the first step, the molar ratio of methyl acrylate to N,N-dimethyl-1,3-amine is 2.0 to 2.2.

[0013] In the first step, the halogenated alkane is a brominated alkane or a chloroalkane.

[0014] In the second step, the molar ratio of the halogenated alkane to the N,N-dimethyl-1,3-amine is 1.0 to 1.1.

[0015] In the second step, the reaction temperature of the reflux reaction is 70° C. to 90° C., and the reaction time is 10 h to 14 h.

[0016] The second technical solution of the present invention is achieved by the following measures: A method for preparing a diester single-tail cationic surfactant is carried out according to the following steps: the first step is to dissolve N,N-dimethyl-1,3-amine in anhydrous ethanol in a reactor, stir evenly, reduce the temperature of the reactor to 0 to 5°C, add methyl acrylate dropwise, and continue to react at room temperature for 20 to 26 hours after the addition is completed;

[0017] In the second step, halogenated alkane is added to the reactor, stirred evenly, and refluxed to react. After the reaction is completed, the reaction product is concentrated and the solvent is removed. The reaction product is then recrystallized with ethyl acetate to obtain a viscous liquid diester single-tail cationic surfactant.

[0018] The third technical solution of the present invention is achieved through the following measures: application of a diester single-tail surfactant in a fracturing fluid additive.

[0019] The fourth technical solution of the present invention is achieved by the following measures: a drainage aid for acid fracturing, wherein the raw materials are composed of 8 to 9.5 parts of anionic surfactant, 0.5 to 2 parts of diester single-tail surfactant, 0 to 1 part of sugar-based surfactant, and the rest is water per 100 parts by mass; the required amount of anionic surfactant, diester single-tail surfactant, sugar-based surfactant and water are stirred and mixed evenly at room temperature to obtain the drainage aid for acid fracturing.

[0020] The following is a further optimization and / or improvement of the fourth technical solution of the above invention:

[0021] The above anionic surfactant is sodium fatty alcohol polyoxyethylene ether carboxylate, and its chemical structural formula is:

[0022]

[0023] Where R1 is C 12 To C 18 Aliphatic hydrocarbon group, n is an integer greater than or equal to 2.

[0024] The sugar-based surfactant is N-alkyl glucosamine, and its chemical structural formula is:

[0025]

[0026] Where R2 is C 12 To C 16 aliphatic hydrocarbon group.

[0027] The present invention provides a low-cost, green and environmentally friendly diester single-tail cationic surfactant. The preparation method of the diester single-tail cationic surfactant is simple to operate, safe and reliable, conducive to industrial production and promotion and application, and has broad market prospects. The acid fracturing drainage agent using the diester single-tail surfactant as a raw material can effectively reduce the interfacial tension of the aqueous solution and meet the technical specifications of the acid fracturing drainage agent. DETAILED DESCRIPTION

[0028] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals known and used in the prior art; unless otherwise specified, the percentages in the present invention are all mass percentages; unless otherwise specified, the solutions in the present invention are all aqueous solutions with water as the solvent, for example, hydrochloric acid solution is a hydrochloric acid aqueous solution; the normal temperature and room temperature in the present invention generally refer to a temperature of 15°C to 25°C, and are generally defined as 25°C.

[0029] The present invention will be further described below in conjunction with embodiments:

[0030] Embodiment 1: The diester single tail surfactant has the chemical structural formula:

[0031]

[0032] Where R is C 12 To C 16 An aliphatic hydrocarbon group, X is chlorine or bromine.

[0033] Example 2: As an optimization of the above example, the diester single-tail surfactant is prepared according to the following steps:

[0034] In the first step, N,N-dimethyl-1,3-amine is dissolved in anhydrous ethanol in a reactor, stirred evenly, the temperature of the reactor is lowered to 0 to 5°C, methyl acrylate is added dropwise, and after the addition is completed, the reaction is continued at room temperature for 20 to 26 hours;

[0035] In the second step, halogenated alkane is added to the reactor, stirred evenly, and refluxed to react. After the reaction is completed, the reaction product is concentrated and the solvent is removed. The reaction product is then recrystallized with ethyl acetate to obtain a viscous liquid diester single-tail cationic surfactant.

[0036] In the present invention, a low-temperature water bath can be used to lower the temperature of the reactor to 0 to 5° C., and rotary evaporation can be used to concentrate the reaction product and remove the solvent.

[0037] The chemical reaction process of the above preparation method is as follows:

[0038] (1) In the first step, preparation of diester intermediate:

[0039]

[0040] (2) In the second step, the product diester single-tail cationic surfactant is prepared:

[0041]

[0042] Example 3: As an optimization of the above example, in the first step, the molar ratio of methyl acrylate to N,N-dimethyl-1,3-amine is 2.0 to 2.2.

[0043] Embodiment 4: As an optimization of the above embodiment, in the first step, the halogenated alkane is a brominated alkane or a chloroalkane.

[0044] Example 5: As an optimization of the above example, in the second step, the molar ratio of the halogenated alkane to N,N-dimethyl-1,3-amine is 1.0 to 1.1.

[0045] Example 6: As an optimization of the above example, in the second step, the reaction temperature of the reflux reaction is 70°C to 90°C, and the reaction time is 10h to 14h.

[0046] Example 7: Application of the diester single-tail surfactant in fracturing fluid additives.

[0047] Example 8: The drainage agent for acid fracturing has the following raw materials, calculated by mass: 8 to 9.5 parts of anionic surfactant, 0.5 to 2 parts of diester single-tail surfactant, 0 to 1 part of sugar-based surfactant, and the rest is water. The required amounts of anionic surfactant, diester single-tail surfactant, sugar-based surfactant and water are stirred and mixed uniformly at room temperature to obtain the drainage agent for acid fracturing.

[0048] The drainage aid for acid fracturing of the present invention can be directly prepared on site using oilfield wastewater such as oilfield produced water and flowback fluid, which is convenient for acid fracturing construction operations.

[0049] Example 9: As an optimization of the above example, the anionic surfactant is sodium fatty alcohol polyoxyethylene ether carboxylate, and its chemical structural formula is:

[0050]

[0051] Wherein, R1 is an aliphatic hydrocarbon group of C12 to C18, and n is an integer greater than or equal to 2.

[0052] Example 10: As an optimization of the above example, the sugar-based surfactant is N-alkyl glucosamine, and its chemical structure is:

[0053]

[0054] Wherein, R2 is an aliphatic hydrocarbon group of C12 to C16.

[0055] Embodiment 11:

[0056] Preparation of diester single-tail cationic surfactant:

[0057] Dissolve 0.1 mol of N,N-dimethyl-1,3-amine in 100 mL of anhydrous ethanol, stir evenly, lower the temperature to below 5°C in an ice-water bath, slowly drop 0.2 mol of methyl acrylate, and continue to react for 24 hours after the addition is complete; add 0.1 mol of hexadecane bromide, stir evenly, raise the temperature to 80°C, reflux for 8 hours, and recover the solvent by rotary evaporation. The reaction product is recrystallized from ethyl acetate to obtain a viscous liquid diester single-tail cationic surfactant DMST-16 with a yield of 89.6%.

[0058] Preparation of drainage agent for acid fracturing:

[0059] Weigh 9.0 parts of sodium lauryl polyoxyethylene ether (3) carboxylate, 1.0 part of DMST-16 and 90 parts of water, stir at room temperature and dissolve evenly to prepare 100 parts of drainage aid for acid fracturing.

[0060] The results of indoor experimental tests on the drainage agent for acid fracturing show that the surface tension of a 0.3% aqueous solution of sodium lauryl polyoxyethylene ether (3) carboxylate is 22.648 mN / m, and the interfacial tension is 4.051 mN / m, which do not meet the industry standards for non-fluorocarbon drainage agents; the surface tension of a 0.3% drainage agent for acid fracturing is 23.738 mN / m, and the interfacial tension is 0.214 mN / m, which meet the industry standards for non-fluorocarbon drainage agents. This shows that the compounding of the diester single-tail cationic surfactant DMST-16 and the anionic surfactant sodium lauryl polyoxyethylene ether (3) carboxylate can significantly reduce the interfacial tension, while greatly reducing the amount of surfactant used and reducing the cost of use.

[0061] Embodiment 12:

[0062] Preparation of diester single-tail cationic surfactant:

[0063] Dissolve 0.1 mol of N,N-dimethyl-1,3-propylenediamine in 100 mL of anhydrous ethanol, stir evenly, lower the temperature to below 5°C in an ice-water bath, slowly drop 0.22 mol of methyl acrylate, and continue to react for 24 hours after the addition is complete; add 0.11 mol of hexadecane bromide, stir evenly, raise the temperature to 80°C, reflux for 12 hours, rotary evaporate to recover the solvent, and recrystallize the reaction product with ethyl acetate to obtain a viscous liquid diester single-tail cationic surfactant DMST-16 with a yield of 94.7%.

[0064] Preparation of drainage agent for acid fracturing:

[0065] Weigh 9.0 parts of sodium lauryl polyoxyethylene ether (3) carboxylate, 0.5 parts of DMST-16, 0.5 parts of N-dodecyl glucosamine and 90 parts of water, stir at room temperature, and dissolve evenly to prepare 100 parts of an acid fracturing drainage agent.

[0066] The results of indoor experimental tests on the drainage agent for acid fracturing showed that the surface tension of 0.3% acid fracturing drainage agent was 24.784mN / m, and the interfacial tension was 0.089mN / m, which met the industry standards for non-fluorocarbon drainage agents. The use of sugar-based surfactants further significantly reduced the interfacial tension, indicating that it has a good composite synergistic effect.

[0067] Embodiment 13:

[0068] Preparation of diester single-tail cationic surfactant:

[0069] Dissolve 0.1 mol of N,N-dimethyl-1,3-propylenediamine in 100 mL of anhydrous ethanol, stir evenly, lower the temperature to below 5°C in an ice-water bath, slowly drop 0.22 mol of methyl acrylate, and continue to react for 24 hours after the addition is complete; add 0.11 mol of hexadecane bromide, stir evenly, raise the temperature to 80°C, reflux for 24 hours, rotary evaporate to recover the solvent, and recrystallize the reaction product with ethyl acetate to obtain a viscous liquid diester single-tail cationic surfactant DMST-16 with a yield of 95.4%.

[0070] Preparation of drainage agent for acid fracturing:

[0071] Weigh 9.0 parts of sodium lauryl polyoxyethylene ether (3) carboxylate, 1.0 part of bis-DMST-16, 0.5 part of N-dodecyl glucosamine and 89.5 parts of water, stir at room temperature, and dissolve evenly to prepare 100 parts of an acid fracturing drainage agent.

[0072] The results of indoor experimental tests on the drainage agent for acid fracturing showed that the surface tension of 0.3% acid fracturing drainage agent was 23.123mN / m, and the interfacial tension was 0.038mN / m, which met the industry standards for non-fluorocarbon drainage agents. The use of sugar-based surfactants further significantly reduced the interfacial tension, indicating that it has a good composite synergistic effect.

[0073] Embodiment 14:

[0074] Preparation of diester single-tail cationic surfactant:

[0075] Dissolve 0.1 mol of N,N-dimethyl-1,3-propylenediamine in 100 mL of anhydrous ethanol, stir evenly, lower the temperature to below 5°C in an ice-water bath, slowly drop 0.22 mol of methyl acrylate, and continue to react for 24 hours after the addition is complete; add 0.11 mol of dodecane bromide, stir evenly, raise the temperature to 80°C, reflux for 12 hours, rotary evaporate to recover the solvent, and recrystallize the reaction product with ethyl acetate to obtain a viscous liquid diester single-tail cationic surfactant DMST-12 with a yield of 94.1%.

[0076] Preparation of drainage agent for acid fracturing:

[0077] Weigh 8.5 parts of sodium lauryl polyoxyethylene ether (3) carboxylate, 1.5 parts of DMST-12, 0.5 parts of N-tetradecyl glucosamine and 89.5 parts of water, stir at room temperature, and dissolve evenly to prepare 100 parts of an acid fracturing drainage agent.

[0078] The results of indoor experimental tests on the drainage agent for acid fracturing showed that the surface tension of 0.3% acid fracturing drainage agent was 23.281mN / m and the interfacial tension was 0.085mN / m, which met the industry standards for non-fluorocarbon drainage agents. The use of sugar-based surfactants further significantly reduced the interfacial tension, indicating that it has a good composite synergistic effect.

[0079] Embodiment 15:

[0080] Preparation of diester single-tail cationic surfactant:

[0081] Dissolve 0.1 mol of N,N-dimethyl-1,3-propylenediamine in 100 mL of anhydrous ethanol, stir evenly, lower the temperature to below 5°C in an ice-water bath, slowly drop 0.22 mol of methyl acrylate, and continue to react for 24 hours after the addition is complete; add 0.11 mol of tetradecane bromide, stir evenly, raise the temperature to 80°C, reflux for 12 hours, rotary evaporate to recover the solvent, and recrystallize the reaction product with ethyl acetate to obtain a viscous liquid diester single-tail cationic surfactant DMST-14 with a yield of 94.5%.

[0082] Preparation of drainage agent for acid fracturing:

[0083] Weigh 8.5 parts of sodium lauryl polyoxyethylene ether (3) carboxylate, 1.5 parts of DMST-14, 0.5 parts of N-hexadecyl glucosamine and 89.5 parts of water, stir at room temperature, and dissolve evenly to prepare 100 parts of an acid fracturing drainage agent.

[0084] The results of indoor experimental tests on the drainage agent for acid fracturing showed that the surface tension of 0.3% acid fracturing drainage agent was 22.605mN / m, and the interfacial tension was 0.002mN / m, which met the industry standards for non-fluorocarbon drainage agents. The use of sugar-based surfactants further significantly reduced the interfacial tension, indicating that it has a good composite synergistic effect.

[0085] The diester single-tail cationic surfactant of the present invention is prepared by a "one-pot method", which is simple, has a high product yield, is safe and reliable, effectively reduces costs, shortens production cycles, and has good composite synergistic characteristics with commonly used anionic surfactants, nonionic surfactants, etc., can effectively reduce surface interfacial tension, and significantly reduce the amount of surfactant used, thereby reducing the cost of use. The acid fracturing drainage agent using the diester single-tail surfactant as a raw material can effectively reduce the surface interfacial tension of the aqueous solution and meet the technical specifications of the acid fracturing drainage agent.

[0086] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A diester single-tail cationic surfactant, characterized in that The chemical structure is: Where R is C 12 To C 16 An aliphatic hydrocarbon group, X is chlorine or bromine.

2. The diester single tail cationic surfactant according to claim 1, characterized in that Prepared according to the following steps: In the first step, N,N-dimethyl-1,3-amine is dissolved in anhydrous ethanol in a reactor, stirred evenly, the temperature of the reactor is lowered to 0 to 5°C, methyl acrylate is added dropwise, and after the addition is completed, the reaction is continued at room temperature for 20 to 26 hours; In the second step, halogenated alkane is added to the reactor, stirred evenly, and refluxed to react. After the reaction is completed, the reaction product is concentrated and the solvent is removed. The reaction product is then recrystallized with ethyl acetate to obtain a viscous liquid diester single-tail cationic surfactant.

3. The diester single tail cationic surfactant according to claim 2, characterized in that In the first step, the molar ratio of methyl acrylate to N,N-dimethyl-1,3-amine is 2.0 to 2.

2.

4. The diester single-tail cationic surfactant according to claim 2 or 3, characterized in that In the first step, the alkyl halide is an alkyl bromide or an alkyl chloride.

5. The diester single-tail cationic surfactant according to any one of claims 2 to 4, characterized in that In the second step, the molar ratio of the halogenated alkane to N,N-dimethyl-1,3-amine is 1.0 to 1.1; or / and, in the second step, the reaction temperature of the reflux reaction is 70° C. to 90° C., and the reaction time is 10 h to 14 h.

6. A method for preparing a diester single-tail cationic surfactant according to any one of claims 1, 3, 4 or 5, characterized in that The process is carried out as follows: first, dissolving N,N-dimethyl-1,3-amine in anhydrous ethanol in a reactor, stirring evenly, lowering the reactor temperature to 0 to 5°C, adding methyl acrylate dropwise, and continuing the reaction at room temperature for 20 to 26 hours after the addition is complete; In the second step, halogenated alkane is added to the reactor, stirred evenly, and refluxed to react. After the reaction is completed, the reaction product is concentrated and the solvent is removed. The reaction product is then recrystallized with ethyl acetate to obtain a viscous liquid diester single-tail cationic surfactant.

7. Use of the diester single-tail cationic surfactant according to any one of claims 1 to 6 in a fracturing fluid additive.

8. A drainage aid for acid fracturing using the diester single-tail cationic surfactant according to any one of claims 1 to 6 as a raw material, characterized in that The raw materials are composed of 8 to 9.5 parts of anionic surfactant, 0.5 to 2 parts of diester single-tail surfactant, 0 to 1 part of sugar-based surfactant, and the rest is water per 100 parts by mass; the required amounts of anionic surfactant, diester single-tail surfactant, sugar-based surfactant and water are stirred and mixed uniformly at room temperature to obtain a drainage agent for acid fracturing.

9. The drainage aid for acid fracturing according to claim 8, characterized in that The anionic surfactant is sodium fatty alcohol polyoxyethylene ether carboxylate, and its chemical structure is: Where R1 is C 12 To C 18 Aliphatic hydrocarbon group, n is an integer greater than or equal to 2.

10. The drainage aid for acid fracturing according to claim 8 or 9, characterized in that The sugar-based surfactant is N-alkyl glucosamine, and its chemical structure is: Where R2 is C 12 To C 16 aliphatic hydrocarbon group.

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