Nanoparticle type nonionic surfactant as well as preparation method and application thereof

Abstract

The invention relates to the field of oil extraction chemistry, and discloses a nanoparticle type nonionic surfactant as well as a preparation method and application thereof. The preparation method of the nonionic surfactant comprises the following steps: in the presence of water and a catalyst, mixing polyether with a structure as shown in a formula I with styrene to carry out polymerization reaction, wherein R is a C10-C20 alkyl group, and n is equal to 5-20. The nonionic surfactant prepared by the method not only has good emulsifying performance, can form an emulsion with crude oil under a micro-disturbance condition, has good oil displacement effect, but also has good structural stability, and can enhance the stability of the emulsion.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemistry, specifically to a nonionic surfactant, its preparation method, and its application. Background Technology

[0002] Surfactant-assisted flooding (SAF) is a technique for enhancing oil recovery. Its core lies in injecting a surfactant slug into the oil reservoir, which displaces the residual oil. Adding a surfactant to the injection water reduces the oil-water interfacial tension, alters rock wettability, emulsifies the crude oil, detaches residual oil films adsorbed on the surface of rock particles, and allows oil droplets or debris to be carried away by the injection water, thereby increasing oil recovery.

[0003] Currently, traditional surfactants used for oil displacement, such as petroleum sulfonates, heavy alkylbenzene sulfonates, and sodium fatty alcohol polyoxyethylene ether sulfate, while inexpensive, suffer from limitations in temperature and salt resistance, particularly in high-salinity reservoirs. With the deepening of oil and gas exploration and development, more and more oilfields face complex geological conditions such as high temperature and high salinity, placing higher demands on the performance of oil displacement agents. Therefore, developing new, low-cost, high-efficiency, temperature- and salt-resistant surfactants has become a key direction for the development of chemical oil displacement technology. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of poor temperature resistance and unstable structure of existing surfactants, and to provide a nanoparticle-type non-ionic surfactant grafted onto the surface of nanoparticles. This nanoparticle-type nonionic surfactant has the characteristics of low development cost, stable structure and excellent emulsification effect.

[0005] To achieve the above objectives, a first aspect of the present invention provides a method for preparing a nonionic surfactant, the method comprising: mixing a polyether of formula I with styrene in the presence of water and a catalyst to carry out a polymerization reaction.

[0006]

[0007] Where R is C 10 -C 20 Alkyl groups, n = 5-20.

[0008] A second aspect of the present invention provides a nonionic surfactant prepared by the above-described preparation method.

[0009] A third aspect of the present invention provides the application of the above-mentioned nonionic surfactant in oil displacement.

[0010] The present invention also provides a nonionic surfactant having the structural formulas shown in Formula III and Formula IV.

[0011]

[0012] Where R is C 10 -C 20 Alkyl groups, n = 5-20.

[0013] Through the above technical solution, the present invention can achieve at least the following beneficial effects:

[0014] (1) The nonionic surfactant prepared by the method described in this invention has good emulsifying properties and can form an emulsion with crude oil under micro-disturbance conditions, thus having a good oil displacement effect.

[0015] (2) The nonionic surfactant prepared by the method described in this invention has good structural stability and can enhance the stability of the emulsion. Attached Figure Description

[0016] Figure 1 This is a transmission electron microscope image of the nonionic surfactant prepared in Example 1.

[0017] Figure 2 This is the infrared spectrum of the nonionic surfactant prepared in Example 1. Detailed Implementation

[0018] 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.

[0019] The first aspect of this invention provides a method for preparing a nonionic surfactant, the method comprising: mixing a polyether of formula I with styrene in the presence of water and a catalyst to carry out a polymerization reaction.

[0020]

[0021] Where R is C 10 -C 20 Alkyl groups, n = 5-20.

[0022] In this invention, preferably, in the polyether with the structure shown in Formula I, R can be C 12 -C 18 Alkyl groups (e.g., C45) 12 C 13 C 14 C 15C 16 C 17 C 18 C 19 C 20 And any two of the above values ​​forming a range and values ​​within that range), n = 9-15 (for example, it can be 9, 10, 11, 12, 13, 14, 15 and any two of the above values ​​forming a range and values ​​within that range).

[0023] In this invention, preferably, the mass ratio of water, polyether of Formula I and styrene is 10:0.05-0.5:2-5, more preferably 10:0.1-0.4:2.5-4.

[0024] In this invention, preferably, the mass ratio of the total mass of the polyether and styrene in the structure shown in Formula I to the mass of the catalyst is 10:0.01-0.3, more preferably 10:0.05-0.1.

[0025] In this invention, preferably, the catalyst is selected from persulfate and / or azomidamine catalysts, more preferably at least one of ammonium persulfate, potassium persulfate and azobisisobutyramidine hydrochloride.

[0026] In this invention, preferably, the polymerization reaction conditions include: a temperature of 60-90°C, preferably 70-80°C (for example, it can be 70, 73, 75, 78, 80, or any two of the above values ​​within a range); a time of 3-5 hours (for example, it can be 3, 3.5, 4, 4.5, 5, or any two of the above values ​​within a range); and a pressure of atmospheric pressure (i.e., 101.325 ± 0.5 kPa).

[0027] In this invention, preferably, the mixing method is stirring.

[0028] In this invention, preferably, the stirring conditions include: a stirring speed of 500-1000 rpm, preferably 600-800 rpm (for example, it can be 600, 620, 650, 680, 700, 730, 750, 770, 800, or any two of the above values ​​within a range); and a stirring time of 2-6 hours, preferably 3-4 hours (for example, it can be 3, 3.5, 4, or any two of the above values ​​within a range).

[0029] In this invention, preferably, styrene is grafted onto the polyether with the structure shown in Formula I in the form of microspheres to form a nonionic surfactant.

[0030] In this invention, preferably, after the polymerization reaction is completed, the obtained product can be further subjected to centrifugation, solid-liquid separation and drying; wherein, the centrifugation conditions can be those commonly used in the art, for example, a rotation speed of 15000-25000 rpm and a time of 1-10 min; the solid-liquid separation can be a method commonly used in the art, for example, filtration; the drying conditions can be those commonly used in the art, for example, a drying temperature of 40-80℃ and a drying time of 10-30 h.

[0031] In this invention, preferably, the polyether with the structure shown in Formula I can be prepared in-house, wherein the preparation method of the polyether with the structure shown in Formula I includes: mixing fatty alcohol polyoxyethylene ether, acrylic acid, polymerization inhibitor, catalyst and solvent and then reacting them.

[0032] In this invention, preferably, when preparing the polyether with the structure shown in Formula I, the mass ratio of the fatty alcohol polyoxyethylene ether to acrylic acid is 10:3-10.

[0033] In this invention, preferably, when preparing the polyether with the structure shown in Formula I, the amount of the catalyst used is 0.5-2 wt% of the total mass of the fatty alcohol polyoxyethylene ether and acrylic acid.

[0034] In this invention, preferably, when preparing the polyether with the structure shown in Formula I, the mass ratio of the fatty alcohol polyoxyethylene ether to the polymerization inhibitor is 10:0.01-0.2.

[0035] In this invention, preferably, when preparing the polyether with the structure shown in Formula I, the catalyst is selected from at least one of p-toluenesulfonic acid and phosphotungstic acid.

[0036] In this invention, preferably, when preparing the polyether with the structure shown in Formula I, the polymerization inhibitor can be selected from agents commonly used in the art that have polymerization inhibitory effects, such as at least one of hydroquinone and p-tert-butylcatechol.

[0037] In this invention, preferably, when preparing the polyether with the structure shown in Formula I, the reaction conditions include: a temperature of 90-110°C (for example, it can be 90, 93, 95, 98, 100, 104, 108, 110, or any two of the above values ​​within a range), and a time of 5-15 h (for example, it can be 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, or any two of the above values ​​within a range).

[0038] In this invention, preferably, when preparing the polyether with the structure shown in Formula I, the fatty alcohol polyoxyethylene ether has the following structure: Where R' can be C 10 -C 20 Alkyl group, n = 5-20; preferably, R' can be C 12 -C 18 Alkyl groups (e.g., C45) 12 C 13 C 14 C 15 C 16 C 17 C 18 C 19 C 20 And any two of the above values ​​forming a range and values ​​within that range), n = 9-15 (for example, it can be 9, 10, 11, 12, 13, 14, 15 and any two of the above values ​​forming a range and values ​​within that range).

[0039] A second aspect of the present invention provides a nonionic surfactant prepared by the above-described preparation method.

[0040] In this invention, preferably, the particle size of the nonionic surfactant is 50-300 nm.

[0041] A third aspect of the present invention provides the application of the above-mentioned nonionic surfactant in oil displacement.

[0042] The present invention also provides a nonionic surfactant having the structural formulas shown in Formula III and Formula IV.

[0043]

[0044] Where R is C 10 -C 20 Alkyl groups, n = 5-20.

[0045] In this invention, preferably, R is C 12 -C 18 Alkyl groups (e.g., C45) 12 C 13 C 14 C 15 C 16 C 17 C 18 C 19 C 20 And any two of the above values ​​forming a range and values ​​within that range); n = 9-15 (for example, it can be 9, 10, 11, 12, 13, 14, 15 and any two of the above values ​​forming a range and values ​​within that range).

[0046] The present invention will be described in detail below through embodiments. In the following embodiments, the emulsification coefficient parameter was measured using an emulsification-demulsification characteristic tester.

[0047] Fatty alcohol polyoxyethylene ether (AEO-9) is a commercially available product from McLean Company [molecular formula: C] 12 H 25 O(CH2CH2O)9H].

[0048] Fatty alcohol polyoxyethylene ether (AEO-3) is a commercially available product from McLean Company [molecular formula: C] 12 H 25 O(CH2CH2O)3H].

[0049] Polyoxyethylene lauryl ether is a commercially available product from McLean Company, catalog number B913466 [molecular formula: HO(CH2CH2O)9C]. 12 H 25 ].

[0050] Styrene is the commercially available product from McLean Company, product number S817905 (styrene, 99%, containing 10-15 ppm of 4-tert-butylcatechol stabilizer).

[0051] The reactants are polyether and styrene with the structure shown in Formula I, and the product is a nonionic surfactant.

[0052] Example 1

[0053] 100g of fatty alcohol polyoxyethylene ether (AEO-9) and 30g of acrylic acid were dissolved in 300g of toluene. Then, 0.65g of toluenesulfonic acid catalyst was added, and the mixture was reacted at 90℃ for 10 hours. Next, 0.015g of hydroquinone polymerization inhibitor was added, and the mixture was reacted again under the same conditions for 1 hour to carry out esterification. The ester was obtained by vacuum distillation. 110g of fatty alcohol polyoxyethylene ether acrylate was obtained. A three-necked flask containing 100g of deionized water was taken, and 2g of fatty alcohol polyoxyethylene ether acrylate was added to the flask. 30g of styrene and 0.16g of potassium persulfate catalyst were added, and the mixture was reacted at 70℃ and 600rpm for 4 hours. After the reaction, the reaction solution was centrifuged (20000rpm, 5min), filtered, and dried (60℃, 24h) to obtain a nonionic surfactant. Figure 1 This is a transmission electron microscope (TEM) image of a nonionic surfactant. Figure 2 (The image shows the infrared spectrum of a nonionic surfactant), and the yield of the product was 83.4%.

[0054] Example 2

[0055] 100g of fatty alcohol polyoxyethylene ether (AEO-9) and 50g of acrylic acid were dissolved in 300g of toluene. Then, 0.9g of toluenesulfonic acid catalyst was added and the mixture was reacted at 100℃ for 8 hours. Then, 0.035g of hydroquinone polymerization inhibitor was added and the mixture was reacted for another hour under the same conditions to carry out esterification. 124g of fatty alcohol polyoxyethylene ether acrylate was obtained by vacuum distillation. A three-necked flask containing 100g of deionized water was taken, and 3g of fatty alcohol polyoxyethylene ether acrylate was added to the flask. 35g of styrene and 0.228g of potassium persulfate catalyst were added and the mixture was reacted at 80℃ and 700rpm for 3 hours. After the reaction was completed, the reaction solution was centrifuged, filtered, and dried to obtain a nonionic surfactant with a yield of 85.9%.

[0056] Example 3

[0057] 100g of fatty alcohol polyoxyethylene ether (AEO-9) and 80g of acrylic acid were dissolved in 300g of toluene. Then, 1.8g of toluenesulfonic acid catalyst was added, and the mixture was reacted at 110℃ for 5 hours. Then, 0.064g of hydroquinone polymerization inhibitor was added, and the mixture was reacted for another hour under the same conditions to carry out esterification. 138g of fatty alcohol polyoxyethylene ether acrylate was obtained by vacuum distillation. A three-necked flask containing 100g of deionized water was taken, and 4g of fatty alcohol polyoxyethylene ether acrylate was added to the flask. 40g of styrene and 0.308g of potassium persulfate catalyst were added, and the mixture was reacted at 60℃ and 800rpm for 5 hours. After the reaction, the reaction solution was centrifuged, filtered, and dried to obtain a nonionic surfactant with a yield of 86.2%.

[0058] Example 4

[0059] 100g of fatty alcohol polyoxyethylene ether (AEO-9) and 100g of acrylic acid were dissolved in 300g of toluene. Then, 3g of toluenesulfonic acid catalyst was added, and the mixture was reacted at 110℃ for 5 hours. Then, 0.1g of hydroquinone polymerization inhibitor was added, and the mixture was reacted for another hour under the same conditions to carry out esterification. 151g of fatty alcohol polyoxyethylene ether acrylate was obtained by vacuum distillation. 1g of fatty alcohol polyoxyethylene ether acrylate was added to a three-necked flask containing 100g of deionized water. 25g of styrene and 0.208g of potassium persulfate catalyst were added, and the mixture was reacted at 70℃ and 600rpm for 4 hours. After the reaction, the reaction solution was centrifuged, filtered, and dried to obtain a nonionic surfactant with a yield of 82.3%.

[0060] Example 5

[0061] Nonionic surfactants were prepared according to the method in Example 1, except that the stirring conditions were changed to 1200 rpm and the stirring time was 3 h. The yield of the product was 84.1%.

[0062] Example 6

[0063] Nonionic surfactants were prepared according to the method in Example 1, except that the stirring conditions were changed to 400 rpm and the stirring time to 3 h. The yield of the product was 80.0%.

[0064] Example 7

[0065] The nonionic surfactant was prepared according to the method in Example 1, except that 45 g of styrene was used. The yield of the product was 88.7%.

[0066] Example 8

[0067] The nonionic surfactant was prepared according to the method in Example 1, except that 10 g of fatty alcohol polyoxyethylene ether (AEO-9) was used. The yield of the product was 83.0%.

[0068] Example 9

[0069] The nonionic surfactant was prepared according to the method of Example 1, except that the amount of potassium persulfate used was 0.5 g. The yield of the product was 84.4%.

[0070] Comparative Example 1

[0071] A nonionic surfactant was prepared according to the method of Example 1, except that styrene was replaced with divinylbenzene. The yield of the product was 88.2%.

[0072] Comparative Example 2

[0073] A nonionic surfactant was prepared according to the method of Example 1, except that acrylic acid was replaced with 2-butenoic acid. The yield of the product was 81.0%.

[0074] Comparative Example 3

[0075] Nonionic surfactants were prepared according to the method of Example 1, except that fatty alcohol polyoxyethylene ether (AEO-9) was replaced with polyoxyethylene lauryl ether. The yield of the product was 84.5%.

[0076] Comparative Example 4

[0077] Nonionic surfactants were prepared according to the method of Example 1, except that fatty alcohol polyoxyethylene ether (AEO-9) was replaced with fatty alcohol polyoxyethylene ether (AEO-3), and the yield of the product was 82.2%.

[0078] Test Example 1

[0079] The nonionic surfactant prepared above was prepared into a solution, and fatty alcohol polyoxyethylene ether was used as a comparative experiment. Then, tests were conducted at an oil-to-water volume ratio of 2:8. The oil phase in the oil-water system includes, but is not limited to, crude oil containing different components, and the water phase includes, but is not limited to, water containing different minerals and surfactants. The specific test method is as follows: the emulsification rate of the nonionic surfactant on the simulated oil was measured at different rotation speeds (Formula 1), and its emulsification coefficient was calculated (Formula 2). The larger the emulsification coefficient, the stronger the emulsification ability. After emulsification, the initial (t=0) emulsified oil volume was measured as soon as possible; then, the emulsified oil volume was measured at intervals of t... i The amount of oil at which the emulsion breaks down is measured at constant intervals, and t is defined. i The ratio of the amount of demulsified oil at a given time to the amount of initial emulsified oil is called the demulsification rate. The demulsification coefficient is calculated (Formula 3). The smaller the demulsification coefficient, the more stable the emulsion.

[0080] The emulsification performance was evaluated according to the method described in patent CN114441384A. The oil used in the experiment was a paraffin-based simulated oil, and the surfactant concentration was 3 wt% for all tests. The test temperature was 25℃. The emulsification coefficients of different experimental results are shown in Table 1.

[0081]

[0082] Among them, E o H0 represents the emulsified oil ratio (%); H1 represents the initial water phase upper interface height (cm); H2 represents the initial oil phase upper interface height; and H2 represents the emulsion zone upper interface height during vibration (cm).

[0083]

[0084] Where ω1 is the lower limit of the blade rotation speed during the emulsification test; ω2 is the upper limit of the blade rotation speed during the emulsification test; E0(ω) is the emulsified oil ratio under different rotation speed conditions; E 0, The set linear proportional emulsified oil ratio curve.

[0085]

[0086] Among them, t s Let D be the time interval, and D0(t) be the demulsification rate, which is the ratio of the amount of demulsified oil at time t to the initial amount of emulsified oil; D 0,st The set linear proportional demulsification rate curve.

[0087] Table 1

[0088] Example number Emulsification coefficient Demulsification coefficient Example 1 1.504 1.421 Example 2 1.607 1.483 Example 3 1.572 1.325 Example 4 1.513 1.546 Example 5 1.432 1.634 Example 6 1.301 1.659 Example 7 1.329 1.603 Example 8 1.380 1.654 Example 9 1.430 1.689 Comparative Example 1 1.213 1.698 Comparative Example 2 1.186 1.818 Comparative Example 3 1.075 1.732 Comparative Example 4 0.989 1.923 Comparative experiment 0.917 1.854

[0089] 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 method for preparing a nonionic surfactant, characterized in that, The method includes: mixing a polyether of Formula I with styrene in the presence of water and a catalyst to carry out a polymerization reaction. Where R is C 10 -C 20 Alkyl groups, n = 5-20.

2. The preparation method according to claim 1, wherein, The mass ratio of water, polyether with the structure shown in Formula I, and styrene is 10:0.05-0.5:2-5, preferably 10:0.1-0.4:2.5-4.

3. The preparation method according to claim 1, wherein, The mass ratio of the total mass of the polyether and styrene in the structure shown in Formula I to the mass of the catalyst is 10:0.01-0.3, preferably 10:0.05-0.

1.

4. The preparation method according to claim 1 or 3, wherein, The catalyst is selected from persulfate and / or azomidamine catalysts, preferably at least one of ammonium persulfate, potassium persulfate and azobisisobutyramidine hydrochloride.

5. The preparation method according to any one of claims 1-3, wherein, In the polyether with the structure shown in Formula I, R is C 12 -C 18 Alkyl groups, n = 9-15.

6. The preparation method according to any one of claims 1-3, wherein, The polymerization reaction conditions include: a temperature of 60-90℃, preferably 70-80℃; and a time of 3-5 hours.

7. The preparation method according to any one of claims 1-3, wherein, The mixing method is stirring.

8. The preparation method according to claim 7, wherein, The stirring conditions include: a stirring speed of 500-1000 rpm, preferably 600-800 rpm; and a stirring time of 2-6 h, preferably 3-4 h.

9. The nonionic surfactant prepared by the preparation method according to any one of claims 1-8.

10. The application of the nonionic surfactant according to claim 9 in oil displacement.

Images