Surfactant compositions and nanoemulsions, and methods of making and using the same

Abstract

This invention relates to the field of surfactants, and discloses a surfactant composition and a nanoemulsion, as well as their preparation method and application. The composition comprises an amphoteric surfactant and a high-flash-point alcohol ether auxiliary, wherein the weight ratio of the amphoteric surfactant to the alcohol ether is 100:30-100. This nanoemulsion exhibits good kinetic stability and low viscosity, and can be used to enhance oil recovery in low-permeability reservoirs, ensuring that the nanoemulsion product is more convenient, safe, and environmentally friendly to use.

Description

Technical Field

[0001] This invention relates to the field of surfactants, and more specifically to a surfactant composition and a nanoemulsion, as well as their preparation methods and applications. Background Technology

[0002] Nanoemulsions are composed of water, surfactants (or co-surfactants), and oil, and generally refer to systems formed by dispersing nano-sized oil droplets in water. Nanoemulsions exhibit excellent kinetic stability and low viscosity, making them promising for applications in agriculture, food, pharmaceuticals, and cosmetics.

[0003] Currently, the preparation methods for nanoemulsions are divided into high-energy dispersion methods and low-energy emulsification methods. High-energy dispersion methods use a high-pressure system capable of generating fracturing force to mix and break up the oil and water phases, producing tiny oil droplets, thereby forming nanoemulsions. Examples of mechanical processes include microjets, high-pressure homogenization, or ultrasound (CN116651288A).

[0004] Low-energy emulsification alters the curvature of the oil-water interface by controlling the composition and temperature of the emulsion system, releasing the chemical energy between components and achieving phase change. There are three pathways for preparing oil-in-water nanoemulsions using low-energy emulsification: phase transition component method, phase transition temperature method, and microemulsion dilution method. These methods are low-cost, require simple equipment, and consume little energy. CN113563861B describes a mixture of anionic and nonionic surfactants used in the preparation of nanoemulsions, with co-surfactants selected from methanol, ethanol, n-butanol, isobutanol, or n-pentanol, and the oil phase being white oil, kerosene, or diesel oil. CN115991983A describes a nanoemulsion using nonionic surfactants such as Tween 60, Triton X-100, or OP-10, with co-surfactants being n-butanol, isopropanol, or n-pentanol, and the oil phase being turpentine or white oil.

[0005] The above-mentioned low-energy emulsification methods for preparing nanoemulsions all use nonionic surfactants and low-molecular-weight alcohol co-surfactants, while existing technologies do not report on the use of alcohol ethers in nanoemulsions. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of preparing nanoemulsions with low molecular weight alcohols in the prior art, and to provide a surfactant composition and nanoemulsion, as well as their preparation method and application.

[0007] Currently, low-molecular-weight alcohols are used to prepare nanoemulsions, while alcohol ethers are ethers containing hydroxyl groups. It is generally believed that the two have very different physicochemical properties. However, the inventors of this invention unexpectedly discovered in experiments that nanoemulsions prepared using alcohol ethers can have better kinetic stability and lower viscosity, which can be used to improve the recovery rate of low-permeability oil reservoirs. This ensures that the use of nanoemulsion products is more convenient, safe, and environmentally friendly.

[0008] Therefore, in order to achieve the above objectives, the first aspect of the present invention provides a surfactant composition, characterized in that the composition comprises an amphoteric surfactant and a high flash point alcohol ether auxiliary, wherein the weight ratio of the amphoteric surfactant to the alcohol ether is 100:30-100.

[0009] A second aspect of the present invention provides a nanoemulsion, characterized in that the nanoemulsion contains a surfactant composition as described above, an oil phase, and water.

[0010] A third aspect of the present invention provides a method for preparing the nanoemulsion as described above, characterized in that the method comprises: mixing a surfactant composition, an oil phase and water.

[0011] A fourth aspect of the present invention provides the application of the nanoemulsion described above in improving the recovery rate of low-permeability oil reservoirs.

[0012] Through the above technical solution, the present invention has achieved at least the following beneficial effects:

[0013] The surfactant composition provided in this invention is particularly advantageous for preparing nanoemulsions for enhancing oil recovery in low-permeability reservoirs. Nanoemulsions prepared using the surfactant composition of this invention exhibit good kinetic stability and low viscosity characteristics, making them suitable for enhancing oil recovery in low-permeability reservoirs. This ensures that the use of nanoemulsion products is more convenient, safe, and environmentally friendly.

[0014] Furthermore, the preparation method of the nanoemulsion provided by this invention is simple, and the nanoemulsion provided by this invention can be used to enhance oil recovery in low-permeability reservoirs, ensuring that the nanoemulsion product is more convenient and safer to use. 。

[0015] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0016] Figure 1 This is the stability result of nanoemulsion system 1-2;

[0017] Figure 2 This is a particle size distribution diagram of nanoemulsion system 1-2;

[0018] Figure 3 This is the particle size distribution diagram of the nanoemulsion system 3-1;

[0019] Figure 4 This is the particle size distribution diagram of the nanoemulsion system 5-2;

[0020] Figure 5 It is the injection pressure of nanoemulsion system 1-2 on core BL02;

[0021] Figure 6 It is the injection pressure of the nanoemulsion system 3-1 on core BL03;

[0022] Figure 7 It is the injection pressure of the nanoemulsion system 5-2 on core BL01. Detailed Implementation

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] The first aspect of the present invention provides a surfactant composition, characterized in that the composition comprises an amphoteric surfactant and a high flash point alcohol ether auxiliary, wherein the weight ratio of the amphoteric surfactant to the alcohol ether is 100:30-100.

[0025] In this invention, the high flash point alcohol ether additive refers to an alcohol ether additive with a flash point of 23-61℃.

[0026] Preferably, in this invention, the weight ratio of the amphoteric surfactant to the alcohol ether is 100:50-100, for example, it can be 100:50, 100:55, 100:60, 100:70, 100:80, 100:90, 100:100, or any range between any two values. When the weight ratio of the amphoteric surfactant to the alcohol ether meets the above range, when this surfactant composition is used to prepare nanoemulsions, the nanoemulsions have better kinetic stability and lower viscosity, and can be further used to improve oil recovery in low-permeability reservoirs.

[0027] In this invention, an amphoteric surfactant refers to a surfactant that contains both anions and cations at one end of the hydrophilic group of the same molecule.

[0028] In this invention, there are no special requirements for the type of amphoteric surfactant, and it can be any common amphoteric surfactant.

[0029] In this invention, the amphoteric surfactant contains a hydrophobic carbon chain of 16-25 carbon atoms; preferably, the amphoteric surfactant contains a hydrophobic carbon chain of 20-24 carbon atoms. These surfactants have relatively long hydrophobic carbon chains and exhibit low oil-water interfacial tension with various oil phases.

[0030] According to a specific embodiment of the present invention, the amphoteric surfactant is selected from betaine-type surfactants; preferably, the amphoteric surfactant is selected from erucamide propyl hydroxysulfonate betaine and / or erucamide propyl betaine. When the amphoteric surfactant is erucamide propyl hydroxysulfonate betaine and / or erucamide propyl betaine, such surfactants have a 22-carbon hydrophobic carbon chain, which makes the surfactant more likely to move to the oil-water interface, thereby reducing interfacial tension.

[0031] In this invention, the erucamide propyl betaine has the following structure:

[0032]

[0033] In this invention, the erucamide propyl hydroxysulfonate betaine has the following structure:

[0034]

[0035] In this invention, the alcohol ether is selected from alcohol ethers with a flash point ≥55℃. These alcohol ethers with a flash point ≥55℃ have a high flash point and better safety, which can ensure that the use of nanoemulsion products is more convenient and safer.

[0036] Preferably, the alcohol ether is selected from any one of ethylene glycol butyl ether, propylene glycol butyl ether, and dipropylene glycol butyl ether.

[0037] In a preferred embodiment of the present invention, the composition consists only of the above-described components.

[0038] In this invention, there is no particular limitation on the preparation method of the surfactant composition. Conventional methods in the art can be used for preparation, such as mixing the components evenly.

[0039] A second aspect of the present invention provides a nanoemulsion, characterized in that the nanoemulsion contains a surfactant composition as described above, an oil phase, and water.

[0040] In this invention, the viscosity of the oil phase at 40°C is less than 5 mPa·s. Preferably, the oil phase is selected from D-limonene and / or turpentine oil.

[0041] In this invention, the weight ratio of the aqueous solution of the surfactant composition to the oil phase is 100:5-15. When the weight ratio of the oil phase to water meets the above range, the surfactant composition is used to prepare nanoemulsions, resulting in nanoemulsions with good kinetic stability and low viscosity. This allows them to be used in low-permeability reservoirs to improve oil recovery and ensures that the use of nanoemulsion products is more convenient, safe, and environmentally friendly.

[0042] Preferably, the weight ratio of the aqueous solution of the surfactant composition to the oil phase is 1.1-2:1.

[0043] In some embodiments of the present invention, preferably, the concentration of the surfactant composition in the nanoemulsion is 1-5% by weight, and more preferably 2-4% by weight.

[0044] In this invention, the content of particles with a diameter of 50-100 nm in the nanoemulsion is 20-50 mol%; the content of particles with a diameter of 100-120 nm is 5%-30 mol%; and the content of particles with a diameter of 120-200 nm is 5-30 mol%.

[0045] In this invention, the particle size and distribution of the nanoemulsion are obtained by testing with a laser particle size analyzer.

[0046] In this invention, the surfactant composition is particularly advantageous for preparing nanoemulsions to enhance oil recovery in low-permeability reservoirs. When the particle size of the nanoemulsion meets the aforementioned range, it further ensures that the nanoemulsion exhibits good kinetic stability and low viscosity.

[0047] According to a particularly preferred embodiment of the present invention, the weight ratio of the amphoteric surfactant to the alcohol ether is 100:66.6-76.9, and the weight ratio of the aqueous solution of the surfactant composition to the oil phase is 100:11.1-17.7.

[0048] A third aspect of the present invention provides a method for preparing the nanoemulsion as described above, characterized in that the method comprises: mixing a surfactant composition, an oil phase and water.

[0049] In this invention, the preparation method of the nanoemulsion includes the following steps:

[0050] S1. Mix the surfactant composition with the first portion of water, and then mix it with the oil phase to form an oil-water mixture system;

[0051] S2. Heat the oil-water mixture until it becomes transparent or semi-transparent to obtain a microemulsion.

[0052] S3. Mix the microemulsion with the second part of water to obtain a nanoemulsion.

[0053] In this invention, the weight ratio of the first part of water to the second part of water in the preparation method of the nanoemulsion is 1:0.5-2.

[0054] Those skilled in the art can determine the amount of each component to be fed in the preparation method based on the content of each component in the above-mentioned nanoemulsion, and this will not be elaborated further.

[0055] According to the present invention, the temperature range reached by heating in step S2 of the above preparation method is 20℃-80℃, wherein the less alcohol ether used in the surfactant composition, the higher the temperature required to prepare the microemulsion.

[0056] A fourth aspect of the present invention provides the application of the nanoemulsion described above in improving the recovery rate of low-permeability oil reservoirs.

[0057] The present invention will be described in detail below through embodiments. In the present invention,

[0058] Erucamide propyl betaine was purchased from Hangzhou Yawei Chemical Co., Ltd.

[0059] Erucamide propyl hydroxysulfonate betaine was purchased from Shanghai Chuxing Chemical Co., Ltd.

[0060] Ethylene glycol butyl ether was purchased from Jiangsu Yida Chemical Co., Ltd.

[0061] Propylene glycol butyl ether was purchased from Jiangsu Yida Chemical Co., Ltd.

[0062] Dipropylene glycol butyl ether was purchased from Jiangsu Yida Chemical Co., Ltd.

[0063] D-Limonene was purchased from Shanghai Jiucheng Industrial Co., Ltd.;

[0064] Turpentine was purchased from Beijing Inocare Technology Co., Ltd.

[0065] The particle size of the nanoemulsion was tested at 25°C using a laser particle size analyzer (model Nano-ZS) manufactured by Malvern Corporation.

[0066] Example

[0067] This embodiment illustrates the preparation method of the nanoemulsion of the present invention.

[0068] Based on the component concentrations in Table 1-5 (the balance being water), the nanoemulsion of the present invention was prepared according to the following method:

[0069] S1. Mix the surfactant composition (betaine-type surfactant and alcohol ether) with the first part of water, and then mix it with the oil phase to form an oil-water mixture system;

[0070] S2. Heat the oil-water mixture to temperature T until the oil-water mixture appears transparent (100% transmittance) or semi-transparent (50% transmittance) to obtain a microemulsion.

[0071] S3. Mix the microemulsion with the second part of water to obtain a nanoemulsion with a mass concentration of 2%.

[0072] The weight ratio of the first part of water to the second part of water is 1:1.

[0073] Table 1

[0074]

[0075] Table 2

[0076]

[0077] Table 3

[0078]

[0079] Table 4

[0080]

[0081] Table 5

[0082]

[0083] Comparative Example 1

[0084] Nanoemulsions were prepared according to the concentrations of nanoemulsions in Table 4 and the methods of the examples. The difference was that sodium dodecyl sulfonate was used instead of erucamide propyl hydroxysulfonate in Comparative Example 1 at the same concentration. The resulting emulsion particles had a size greater than 1000 micrometers and a transmittance of less than 10%, therefore, this comparative example could not prepare a nanoemulsion. Nanoemulsions could not be prepared using non-amphoteric surfactants, so no experimental data can be provided.

[0085] Comparative Example 2

[0086] Nanoemulsions were prepared according to the concentrations of nanoemulsions in Table 4 and the methods of the examples. The difference was that propylene glycol was used instead of propylene glycol butyl ether at the same concentration in Comparative Example 2. The resulting emulsion particles had a size greater than 1000 micrometers and a transmittance of less than 10%, therefore, this comparative example could not prepare a nanoemulsion.

[0087] Comparative Example 3

[0088] Nanoemulsions were prepared according to the concentrations of nanoemulsions in Table 4 and the methods of the examples. The difference was that in Comparative Example 3, n-butyl ether was used instead of propylene glycol butyl ether at the same concentration. The resulting emulsion particles had a size greater than 1000 micrometers, and a transmittance of less than 10%, therefore, this comparative example could not prepare a nanoemulsion.

[0089] Comparative Example 4

[0090] Nanoemulsions were prepared according to the concentrations of nanoemulsions in Table 4 and the methods of the examples. The difference was that in Comparative Example 4, dodecyl alcohol ether was used instead of propylene glycol butyl ether at the same concentration. The resulting emulsion particles had a size greater than 1000 micrometers and a transmittance of less than 10%, therefore, this comparative example could not prepare a nanoemulsion.

[0091] Comparative Example 5

[0092] Nanoemulsions were prepared according to the concentrations of nanoemulsions in Table 4 and the methods of the examples. The difference was that in Comparative Example 5, the weight ratio of erucamide propyl hydroxysulfonate betaine to propylene glycol butyl ether was 3:5. The resulting emulsion particles had a size greater than 1000 micrometers and a transmittance of less than 10%, therefore, this comparative example could not prepare a nanoemulsion.

[0093] Test case

[0094] The stability of the nanoemulsions in the examples (systems 1-2) was tested using a stability analyzer (model Turbiscan). Figure 1 As shown, the transmitted light intensity of the entire nanoemulsion system did not change significantly within 15 days of the experiment, indicating that the nanoemulsion system did not undergo demulsification or aggregation within 15 days and has good stability.

[0095] The viscosity of the nanoemulsions obtained in the examples was tested using a rotational viscometer (Brookfield DV-III), and the average particle size was measured using a Malvern laser particle size analyzer (nano-ZS). The results are shown in Table 6. Core displacement experiments were conducted using the 1-2, 3-1, and 5-2 systems from the examples to investigate the oil recovery enhancement effect of the nanoemulsions. Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 The particle size distribution and injection pressure curves in the core of three nanoemulsion systems are presented respectively. The pressure curves demonstrate that injecting the nanoemulsions can improve the recovery rate of low-permeability reservoirs.

[0096] Table 6

[0097]

[0098]

[0099] The nanoemulsion prepared in this invention can be used to enhance oil recovery in low-permeability reservoirs. A 0.5% (w / w) nanoemulsion (diluted with water to systems 1-2, 3-1, and 5-2) was injected into a low-permeability core. Relevant data from the three core displacement experiments are summarized in Table 7. The experimental temperature was 45℃, the core was a natural Bailey core with dimensions of 2.5 cm in diameter and 30 cm in length, and the nanoemulsion injection volume was 3-4.5 PV.

[0100] Table 7

[0101]

[0102] The results of the examples show that the nanoemulsion provided by the present invention can be used to improve the recovery rate of low-permeability oil reservoirs, and can ensure that the nanoemulsion products are more convenient and safer to use.

[0103] The inventors of this invention have also discovered that when a non-amphoteric surfactant is used instead of the amphoteric surfactant described in the examples, or a non-high flash point alcohol ether auxiliary is used instead of the high flash point alcohol ether auxiliary in the examples, or the weight ratio of the amphoteric surfactant to the high flash point alcohol ether auxiliary is not in the range of 100:30-100, the resulting emulsion particles have a size greater than 1000 micrometers and a transmittance of less than 10%, thus making it impossible to prepare nanoemulsions.

[0104] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A surfactant composition, characterized in that, The composition comprises an amphoteric surfactant and a high flash point alcohol ether auxiliary, wherein the weight ratio of the amphoteric surfactant to the alcohol ether is 100:30-100.

2. The composition according to claim 1, wherein, The weight ratio of the amphoteric surfactant to the alcohol ether is 100:50-100; And / or, the amphoteric surfactant contains a hydrophobic carbon chain of 16-24 carbon atoms; Preferably, the amphoteric surfactant contains a hydrophobic carbon chain of 20-24 carbon atoms.

3. The composition according to claim 1 or 2, wherein, The amphoteric surfactant is selected from betaine-type surfactants; Preferably, the amphoteric surfactant is selected from erucamide propyl hydroxysulfonate betaine and / or erucamide propyl betaine.

4. The composition according to claim 1, wherein, The alcohol ether is selected from alcohol ethers with a flash point ≥ 55℃; Preferably, the alcohol ether is selected from any one of ethylene glycol butyl ether, propylene glycol butyl ether, and dipropylene glycol butyl ether.

5. A nanoemulsion, characterized in that, The nanoemulsion contains the surfactant composition according to any one of claims 1-4, an oil phase, and water.

6. The nanoemulsion according to claim 5, wherein, The viscosity of the oil phase at 40°C is less than 5 mPa·s; Preferably, the oil phase is selected from D-limonene and / or turpentine.

7. The nanoemulsion according to claim 5 or 6, wherein, The concentration of the surfactant composition in the nanoemulsion is 1-5% by weight, preferably 2-4% by weight; Preferably, the weight ratio of the surfactant composition to the oil phase is 1.1-2:

1.

8. The nanoemulsion according to claim 5, wherein, The nanoemulsion contains 20-50% by weight particles with a diameter of 50-100 nm; 5-30% by weight particles with a diameter greater than 100 nm and less than or equal to 120 nm; and 5-30% by weight particles with a diameter greater than 120 nm and less than or equal to 200 nm.

9. A method for preparing the nanoemulsion according to any one of claims 5-8, characterized in that, The method includes mixing a surfactant composition, an oil phase, and water.

10. The method according to claim 9, wherein, The method includes the following steps: S1. Mix the surfactant composition with the first portion of water, and then mix it with the oil phase to form an oil-water mixture system; S2. Heat the oil-water mixture until it becomes transparent or semi-transparent to obtain a microemulsion. S3. Mix the microemulsion with the second part of water to obtain a nanoemulsion.

11. The preparation method according to claim 10, wherein, The temperature reached in step S2 is 20-80℃; And / or, the weight ratio of the first part of water to the second part of water is 1:0.5-2.

12. The application of the nanoemulsion according to any one of claims 5-8 and / or the nanoemulsion prepared by the preparation method according to any one of claims 9-11 in improving the recovery rate of low-permeability reservoirs.

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