Alkyl phenylamine polyether zwitterionic surfactant as well as preparation method and application thereof

Abstract

The invention provides an alkyl phenylamine polyether zwitterionic surfactant as well as a preparation method and application thereof. The surfactant is shown as a formula (I), wherein in the formula (I), R1 is selected from C4-C30 alkyl; r2 is selected from H and C1-C10 alkyl groups; r3 is selected from H and C1-C10 alkyl groups; r4 is selected from H, C1-C4 alkyl and-CH2COO (M) n; the (Polyether) 1 is selected from (PO) x1 and / or (EO) y1, the (Polyether) 2 is selected from (PO) x2 and / or (EO) y2, x1, x2, y1 and y2 are independently selected from any integer between 0 and 50, x1 + x2 + y1 + y2 = 1-50, the structure of PO is-CH (CH3) CH2O-, and the structure of EO is-CH2CH2O-; m comprises at least one of alkali metal ions and alkaline earth metal ions, when M is the alkali metal ions, n is 1, and when M is the alkaline earth metal ions, n is 0.5; xi-is an anion, wherein i is the number of charges of the anion. The alkyl phenylamine polyether zwitterionic surfactant provided by the invention can effectively reduce the viscosity of thickened oil and can obviously improve the recovery rate of the thickened oil.

Description

Technical Field

[0001] This invention relates to the field of surfactant technology, and more specifically, to an alkylphenylammonium polyether zwitterionic surfactant, its preparation method, and its application. Background Technology

[0002] Enhanced oil recovery (EOR), also known as tertiary oil recovery, involves injecting additional substances into oil-bearing reservoirs to recover oil. With the development of oilfields, enhanced oil recovery technologies have been widely applied. The main methods of enhanced oil recovery include chemical flooding, thermal recovery, gas flooding, and microbial flooding. Chemical flooding includes polymer flooding, surfactant flooding, foam flooding, alkaline flooding, and combined flooding using these chemical substances. Depending on the mechanism, the main functions of chemical flooding include reducing interfacial tension (IFT), altering wettability, emulsification, and controlling flowability. In recent years, chemical flooding technology has become an important means of improving oil recovery in the oilfield industry.

[0003] Heavy oil, also known as "heavy crude oil," is characterized by high density, high viscosity, and low light oil content. The extraction of heavy oil reservoirs is challenging, primarily due to the high viscosity and poor fluidity of the crude oil, resulting in poor sweep efficiency during displacement with conventional displacing fluids (such as hot water). Conventional methods are insufficient for extracting heavy oil; therefore, specialized technological measures are necessary, such as thermal recovery, chemical viscosity reduction, biological recovery, and combinations thereof. In recent years, the use of chemical viscosity reduction methods for heavy oil extraction has received increasing attention.

[0004] Currently, the surfactants used for enhanced oil recovery both domestically and internationally mainly include surfactants modified from refining byproducts such as petroleum sulfonates and heavy alkylbenzene sulfonates (CN1203935A, CN1566258A, CN1426833A). These surfactants have the advantages of wide availability and low cost, and can be successfully applied in the development of ordinary oil reservoirs. However, their effects are generally not ideal in the development of heavy oil reservoirs. Therefore, developing a surfactant with a good viscosity-reducing effect for heavy oil reservoirs is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide an alkylphenylammonium polyether zwitterionic surfactant, its preparation method and application, in order to solve the technical problems of unsatisfactory viscosity reduction and poor oil displacement effect of surfactants in heavy oil reservoir development.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides an alkylphenylammonium polyether zwitterionic surfactant, the structure of which is shown in formula (I):

[0008]

[0009] In formula (I), R1 is selected from C4 to C5. 30 Hydrocarbon group; R2 is selected from H, C1-C1. 10 Hydrocarbon group; R3 is selected from H, C1-C1. 10 Hydrocarbon group; R4 is selected from H, C1-C4 hydrocarbon groups, and -CH2COO(M). n ;

[0010] (Polyether)1 is selected from (PO) x1 and / or (EO) y1 (Polyether)2 is selected from (PO). x2 and / or (EO) y2 x1, x2, y1, and y2 are each independently selected from any integer between 0 and 50, and x1 + x2 + y1 + y2 = 1 to 50. The structure of PO is -CH(CH3)CH2O-, and the structure of EO is -CH2CH2O-. M includes at least one of alkali metal ions and alkaline earth metal ions. When M is an alkali metal ion, n is 1, and when M is an alkaline earth metal ion, n is 0.5. X i- is an anion, where i is the charge number of the anion.

[0011] The alkylphenylammonium polyether zwitterionic surfactant provided by this invention can emulsify and solubilize heavy oil, significantly reduce the viscosity of heavy oil, and thus improve the recovery rate of heavy oil.

[0012] According to some embodiments of the present invention, R1 is selected from C4 to C5. 30 Alkyl, C4-C 30 alkenyl, C6-C 30 The aryl group is preferably derived from C4 to C5. 30 alkyl.

[0013] According to some embodiments of the present invention, R2 is selected from H, C1 to C2. 10 Alkyl groups, C2-C 10 alkenyl, C6-C 10 The aryl group is preferably selected from H, C1 to C1. 10 Alkyl groups, more preferably H-, C1-C6 alkyl groups.

[0014] According to some embodiments of the present invention, R3 is selected from H, C1 to C. 10 Alkyl groups, C2-C 10 alkenyl, C6-C 10 The aryl group is preferably selected from H, C1 to C1. 10 Alkyl groups, more preferably H-, C1-C6 alkyl groups.

[0015] According to some embodiments of the present invention, R4 is selected from H, C1-C4 alkyl, and C2-C4 alkenyl.

[0016] According to some embodiments of the present invention, x1, x2, y1, and y2 are each independently selected from any integer between 0 and 30, for example, they can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 22, 25, 26, 28, 30, etc.

[0017] According to some embodiments of the present invention, x1, x2, y1, and y2 are each independently selected from any integer between 0 and 20.

[0018] According to some embodiments of the present invention, x1+x2+y1+y2=2~30.

[0019] According to some embodiments of the present invention, x1+x2+y1+y2=4~20.

[0020] According to some embodiments of the present invention, M includes at least one of sodium ions, potassium ions, calcium ions, and magnesium ions.

[0021] In this invention, X i- There are no special restrictions on i. If i is 1, X i- Can be selected from F - Cl - ,Br - I - NO3 - HSO4 - CH3COO - HO-C6H4-COO - CH3-C6H4-SO3 - CH3SO3 - HO-CH2COO - CH3CH(OH)COO - Any one of them; if i is 2, X i- It can be selected from SO4 2- Dicarboxylic acid ions (e.g., oxalate, malonic acid, succinate, glutarate, adipic acid, tartrate, etc.); if i is 3, X i- Citrate can be chosen; if i is 4, X i- One option is to choose tetrabenzoate. Furthermore, X i- In addition to being a simple anion, it can also be a polyanion, such as polyphosphate, polyacrylate, etc.

[0022] In a second aspect, the present invention provides a method for preparing the alkylphenylamine polyether zwitterionic surfactant described in the first aspect, comprising: reacting an alkylaniline with an epoxy compound, and optionally performing end-capping treatment after the reaction to obtain an alkylaniline polyether; and performing a quaternization reaction between the alkylaniline polyether and a quaternizing agent to obtain the alkylphenylamine polyether zwitterionic surfactant.

[0023] The structure of the alkylaniline is shown in formula (2):

[0024]

[0025] In equation (2), R1 is selected from C4 to C5. 30 Hydrocarbon group; R2 is selected from H, C1-C1. 10 Hydrocarbon group; R3 is selected from H, C1-C1. 10 Hydrocarbon group.

[0026] In this invention, the alkylaniline can be purchased directly or prepared in-house. The preparation method can employ existing methods for preparing alkylanilines, for example: nitrating alkylbenzene to obtain alkylnitrobenzene; then hydrogenating the alkylnitrobenzene to obtain alkylaniline.

[0027] According to some embodiments of the present invention, R1 is selected from C4 to C5. 30 Alkyl, C4-C 30 alkenyl, C6-C 30 The aryl group is preferably derived from C4 to C5. 30 alkyl.

[0028] According to some embodiments of the present invention, R2 is selected from H, C1 to C2. 10 Alkyl groups, C2-C 10 alkenyl, C6-C 10 The aryl group is preferably selected from H, C1 to C1. 10 Alkyl groups, more preferably H-, C1-C6 alkyl groups.

[0029] According to some embodiments of the present invention, R3 is selected from H, C1 to C. 10 Alkyl groups, C2-C 10 alkenyl, C6-C 10 The aryl group is preferably selected from H, C1 to C1. 10 Alkyl groups, more preferably H-, C1-C6 alkyl groups.

[0030] According to some embodiments of the present invention, the epoxy compound is selected from C2 to C3 epoxy compounds.

[0031] According to some embodiments of the present invention, the epoxy compound includes ethylene oxide and / or propylene oxide.

[0032] According to some embodiments of the present invention, the capping agent is selected from at least one of halogenated hydrocarbons, organic acids, compounds containing anhydride groups, and compounds containing acyl halide groups.

[0033] According to some embodiments of the present invention, the capping agent includes at least one selected from iodomethane, iodoethane, iodopropane, iodoethylene, acetic acid, acetic anhydride, and acetyl chloride.

[0034] According to some embodiments of the present invention, the quaternizing agent includes at least one of sodium chloroacetate, potassium chloroacetate, sodium bromoacetate, and potassium bromoacetate.

[0035] According to some embodiments of the present invention, the molar ratio of the epoxy compound to the alkyl aniline is (1-50):1, preferably (2-30):1, and more preferably (4-20):1.

[0036] According to some embodiments of the present invention, the molar ratio of the capping agent to alkylaniline is (0-2.6):1, preferably (2-2.4):1.

[0037] According to some embodiments of the present invention, the molar ratio of the quaternizing agent to alkylaniline is (1-5):1, preferably (1-2):1.

[0038] According to some embodiments of the present invention, the reaction conditions for the reaction of the alkylaniline with the epoxy compound include: a reaction temperature of 100-200°C and a reaction pressure of 0-5 MPa.

[0039] According to some embodiments of the present invention, the reaction temperature of the alkylaniline reacting with the epoxy compound is 140–170°C.

[0040] According to some embodiments of the present invention, the reaction pressure of the reaction between the alkylaniline and the epoxy compound is 0.2 to 1 MPa.

[0041] According to some embodiments of the present invention, the reaction of the alkylaniline with the epoxy compound is carried out in the presence of a basic catalyst.

[0042] According to some embodiments of the present invention, the alkaline catalyst comprises at least one selected from alkali metals, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal alkoxides, and alkali metal oxides, preferably at least one selected from sodium hydroxide and potassium hydroxide.

[0043] According to some embodiments of the present invention, the amount of alkaline catalyst is 0.1 to 10 wt% of the mass of alkylaniline, preferably 0.5 to 5.0 wt%.

[0044] According to some embodiments of the present invention, the temperature of the quaternization reaction is 20–80°C.

[0045] According to some embodiments of the present invention, the temperature of the quaternization reaction is 60–80°C.

[0046] According to some embodiments of the present invention, the quaternization reaction takes 0.5 to 10 hours.

[0047] According to some embodiments of the present invention, the quaternization reaction takes 5 to 10 hours.

[0048] According to some embodiments of the present invention, the quaternization reaction is carried out in the presence of a basic catalyst.

[0049] According to some embodiments of the present invention, the alkaline catalyst comprises at least one selected from alkali metals, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal alkoxides, and alkali metal oxides, preferably at least one selected from sodium hydroxide and potassium hydroxide.

[0050] According to some embodiments of the present invention, the molar ratio of the alkaline catalyst to the alkyl aniline polyether is (0.1-5):1.

[0051] Thirdly, the present invention provides an oil displacement agent comprising the alkylphenylamine polyether zwitterionic surfactant described in the first aspect or the alkylphenylamine polyether zwitterionic surfactant prepared by the preparation method described in the second aspect, and water.

[0052] According to some embodiments of the present invention, the mass ratio of the alkylphenylammonium polyether zwitterionic surfactant to water is 1:(50-2000), preferably 1:(80-500).

[0053] In this invention, the water used to prepare the oil displacement agent can be at least one of the following: mineralized water, oilfield injection water, formation water, seawater, rainwater, river water, etc., with a total mineralization range of 0 to 300,000 mg / L, preferably water with a total mineralization range of 1,000 to 50,000 mg / L.

[0054] In addition, to enhance the oil displacement effect, the oil displacement agent provided by the present invention may also include additives commonly used in the art, such as polyether polyols, monoethanolamine, diethanolamine, sodium citrate, EDTA, etc.

[0055] Fourthly, the present invention provides the application of the alkylphenylamine polyether zwitterionic surfactant described in the first aspect, or the alkylphenylamine polyether zwitterionic surfactant prepared by the preparation method described in the second aspect, or the oil displacement agent described in the third aspect, in oil recovery, especially in enhanced oil recovery of heavy oil reservoirs.

[0056] The beneficial effects of this invention are at least as follows:

[0057] The alkylphenylammonium polyether zwitterionic surfactant provided by this invention can effectively reduce the viscosity of heavy oil and significantly improve the recovery rate of heavy oil. It can be used for heavy oil extraction and has broad application prospects. Detailed Implementation

[0058] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely for illustrating this patent and do not limit the scope of protection of this invention in any way.

[0059] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the reagents used in the following embodiments are conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or by existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, the experimental methods are conventional methods.

[0060] Example 1

[0061] 1 mol of octylaniline and 2 g of sodium hydroxide were added to a reactor equipped with a condenser, a stirrer, and a gas disperser. The mixture was heated to 80°C while being purged with nitrogen and stirred for 1 hour. The vacuum system was then activated, and the system was evacuated for 1 hour to remove water. The system was then purged with nitrogen four times to remove air. The reaction temperature was then adjusted to 150°C, and 4 mol of propylene oxide and 2 mol of ethylene oxide were slowly introduced while maintaining a pressure ≤0.5 MPa. After the reaction was completed, the system was purged with nitrogen, and 2.1 mol of iodomethane was added. The mixture was reacted at 90°C for 1 hour, cooled, neutralized, and dehydrated to obtain 0.98 mol of octylaniline polyoxypropylene (4) polyoxyethylene (2) dimethyl ether.

[0062] 0.98 mol of octylaniline polyoxypropylene (4) polyoxyethylene (2) dimethyl ether was dissolved in 500 mL of benzene and added to a reaction vessel equipped with a condenser, a water separator, a dropper and a stirrer. 1.96 mol of sodium hydroxide was added and stirred at 50 °C for 2 h. Then 1.25 mol of sodium chloroacetate was added and reacted at 75 °C for 8 h to obtain octylphenylammonium polyether zwitterionic surfactant.

[0063] Example 2

[0064] 1 mol of dodecylaniline and 2.5 g of sodium hydroxide were added to a reactor equipped with a condenser, a stirrer, and a gas disperser. The mixture was heated to 80°C while being purged with nitrogen, and stirred for 1 hour. The vacuum system was then activated, and the system was evacuated for 1 hour to remove water. The system was then purged with nitrogen four times to remove air. The reaction temperature was then adjusted to 150°C, and 8 mol of ethylene oxide was slowly introduced while maintaining a pressure ≤0.5 MPa. After the reaction was completed, the system was purged with nitrogen, and 2.1 mol of iodoethane was added. The mixture was reacted at 90°C for 1 hour, cooled, neutralized, and dehydrated to obtain 0.97 mol of dodecylaniline polyoxyethylene (8) diethyl ether.

[0065] 0.97 mol of dodecyl aniline polyoxyethylene (8) diethyl ether was dissolved in 1000 mL of benzene and added to a reaction vessel equipped with a condenser, a water separator, a dropper and a stirrer. Then 1.5 mol of sodium hydroxide was added and stirred at 60 °C for 2 h. Then 1.2 mol of sodium chloroacetate was added and reacted at 75 °C for 10 h to obtain dodecyl aniline polyether zwitterionic surfactant.

[0066] Example 3

[0067] 1 mol of dihexylaniline and 3 g of sodium hydroxide were added to a reactor equipped with a condenser, a stirrer, and a gas disperser. The mixture was heated to 80°C while being purged with nitrogen and stirred for 1 hour. The vacuum system was then activated, and the system was evacuated for 1 hour to remove water. The system was then purged with nitrogen four times to remove air. The reaction temperature was then adjusted to 150°C, and 3 mol of propylene oxide and 8 mol of ethylene oxide were slowly introduced while maintaining a pressure ≤0.5 MPa. After the reaction was completed, the system was purged with nitrogen, and 2.2 mol of iodoethane was added. The mixture was reacted at 90°C for 2 hours. After cooling, the mixture was neutralized and dehydrated to obtain 0.96 mol of dihexylaniline polyoxypropylene (3) polyoxyethylene (8) diethyl ether.

[0068] 0.96 mol of dihexylaniline polyoxypropylene (3) polyoxyethylene (8) diethyl ether was dissolved in 1500 mL of benzene and added to a reaction vessel equipped with a condenser, a water separator, a dropper and a stirrer. 2.1 mol of potassium hydroxide was added and stirred at 60 °C for 2 h. Then 1.2 mol of sodium chloroacetate was added and reacted at 80 °C for 8 h to obtain dihexylphenylammonium polyether zwitterionic surfactant.

[0069] Example 4

[0070] 0.5 mol of triacontanilide and 3 g of potassium hydroxide were added to a reactor equipped with a condenser, a stirrer, and a gas disperser. The mixture was heated to 80°C while being purged with nitrogen and stirred for 1 hour. The vacuum system was then activated, and the system was evacuated for 1 hour to remove water. The system was then purged with nitrogen four times to remove air. The reaction temperature was then adjusted to 160°C, and 10 mol of ethylene oxide was slowly introduced while maintaining a pressure ≤0.5 MPa. After the reaction was complete, the system was purged with nitrogen, and 1.1 mol of iodomethane was added. The mixture was reacted at 95°C for 2 hours. After cooling, the mixture was neutralized and dehydrated to obtain 0.49 mol of triacontanilide polyoxyethylene (20) dimethyl ether.

[0071] 0.49 mol triacontylaniline polyoxyethylene (20) dimethyl ether was dissolved in 1000 mL of toluene and added to a reaction vessel equipped with a condenser, a water separator, a dropper and a stirrer. 0.6 mol sodium hydroxide was added and stirred at 65 °C for 2 h. Then 0.55 mol sodium chloroacetate was added and reacted at 75 °C for 8 h to obtain triacontylaniline polyether zwitterionic surfactant.

[0072] Example 5

[0073] 1 mol of tributylaniline and 4 g of sodium hydroxide were added to a reactor equipped with a condenser, a stirrer, and a gas disperser. The mixture was heated to 80°C while being purged with nitrogen and stirred for 1 hour. The vacuum system was then activated, and the system was evacuated for 1 hour to remove water. The system was then purged with nitrogen four times to remove air. The reaction temperature was then adjusted to 160°C, and 4 mol of propylene oxide was slowly introduced while maintaining a pressure ≤0.5 MPa. After the reaction was completed, the system was purged with nitrogen, and 2.1 mol of iodomethane was added. The mixture was reacted at 95°C for 2 hours. After cooling, the mixture was neutralized and dehydrated to obtain 0.97 mol of tributylaniline polyoxypropylene (4) dimethyl ether.

[0074] 0.97 mol of tributylaniline polyoxypropylene (4) dimethyl ether was dissolved in 1500 mL of benzene and added to a reaction vessel equipped with a condenser, a water separator, a dropper and a stirrer. 1.5 mol of potassium hydroxide was added and stirred at 65 °C for 2 h. Then 1.1 mol of sodium chloroacetate was added and reacted at 80 °C for 10 h to obtain tributylphenylammonium polyether zwitterionic surfactant.

[0075] Comparative Example 1

[0076] The surfactant is sodium petroleum sulfonate (Daqing Refinery).

[0077] Comparative Example 2

[0078] The surfactant was sodium octyl aniline polyoxypropylene (4) polyoxyethylene (2) dimethyl ether benzenesulfonate, which was synthesized according to the method in CN202010624678.2.

[0079] Performance Evaluation

[0080] The surfactants prepared in the above embodiments and comparative examples were mixed with injection water from Shengli Oilfield (composition shown in Table 1) to obtain oil displacement agents.

[0081] Table 1. Injected Water in Shengli Oilfield

[0082]

[0083] The viscosity reduction and oil recovery rates of the above-mentioned oil displacement agents were tested, and the results are shown in Table 2.

[0084] The testing method is as follows:

[0085] (1) Viscosity reduction rate:

[0086] The viscosity reduction rate was determined using a Bourdon viscometer DV-III according to the method outlined in QSH1020 1519-2013, General Technical Conditions for Heavy Oil Viscosity Reducers. The test crude oil used was Shengli Gudao heavy oil, with a viscosity of 2220 mPa·s and a density of 0.96 g / cm³. 3 .

[0087] (2) Improve heavy oil recovery:

[0088] According to the performance test method of composite oil displacement system in SY / T6424-2000, the physical simulation oil displacement effect test of composite oil displacement system was carried out on a core with a length of 30cm, a diameter of 2.5cm, and a permeability of 0.5μm². The temperature was 90℃. First, water was injected from Shengli Oilfield to drive the water to a water cut of 98wt%. After the water drive was completed, 0.3pv (core pore volume) of oil displacement agent was injected and the water cut was driven to 98wt%. The increase in heavy oil recovery rate was calculated based on the change in the volume of produced heavy oil.

[0089] Table 2 Performance Evaluation Results of Oil Displacement Agents

[0090]

[0091] As can be seen from Table 2, compared with existing oil displacement surfactants, the alkylphenylammonium polyether zwitterionic surfactant provided by this invention can effectively reduce the viscosity of heavy oil and significantly improve the recovery rate of heavy oil.

[0092] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. An alkylphenylammonium polyether zwitterionic surfactant, the structure of which is shown in formula (I): In formula (I), R1 is selected from C4 to C5. 30 Hydrocarbon group; R2 is selected from H, C1-C1. 10 Hydrocarbon group; R3 is selected from H, C1-C1. 10 Hydrocarbon group; R4 is selected from H, C1-C4 hydrocarbon groups, and -CH2COO(M). n ; (Polyether)1 is selected from (PO) x1 and / or (EO) y1 (Polyether)2 is selected from (PO) x2 and / or (EO) y2 x1, x2, y1, and y2 are each independently selected from any integer between 0 and 50, and x1 + x2 + y1 + y2 = 1 to 50. The structure of PO is -CH(CH3)CH2O-, and the structure of EO is -CH2CH2O-. M includes at least one of alkali metal ions and alkaline earth metal ions. When M is an alkali metal ion, n is 1, and when M is an alkaline earth metal ion, n is 0.

5. X i- is an anion, where i is the charge number of the anion.

2. The alkylphenylammonium polyether zwitterionic surfactant according to claim 1, characterized in that, R1 is selected from C4~C 30 Alkyl, C4-C 30 alkenyl, C6-C 30 The aryl group is preferably derived from C4 to C5. 30 alkyl; And / or, R2 is selected from H, C1 to C 10 Alkyl groups, C2-C 10 alkenyl, C6-C 10 The aryl group is preferably derived from H, C1 to C1. 10 Alkyl groups, more preferably H-, C1-C6 alkyl groups; And / or, R3 is selected from H, C1 to C 10 Alkyl groups, C2-C 10 alkenyl, C6-C 10 The aryl group is preferably derived from H, C1 to C1. 10 Alkyl groups, more preferably H-, C1-C6 alkyl groups; And / or, R4 is selected from H, C1-C4 alkyl, C2-C4 alkenyl; And / or, x1, x2, y1, y2 are each independently selected from any integer between 0 and 30; preferably, x1, x2, y1, y2 are each independently selected from any integer between 0 and 20; And / or, x1+x2+y1+y2=2~30; preferably, x1+x2+y1+y2=4~20; And / or, M includes at least one of sodium ions, potassium ions, calcium ions, and magnesium ions.

3. The method for preparing the alkylphenylammonium polyether zwitterionic surfactant according to claim 1 or 2, characterized in that, include: Alkylaniline is reacted with an epoxy compound, and optionally end-capping is performed after the reaction to obtain alkylaniline polyether; the alkylaniline polyether is then subjected to a quaternization reaction with a quaternizing agent to obtain the alkylaniline polyether zwitterionic surfactant. The structure of the alkylaniline is shown in formula (2): In equation (2), R1 is selected from C4 to C5. 30 Hydrocarbon group; R2 is selected from H, C1-C1. 10 Hydrocarbon group; R3 is selected from H, C1-C1. 10 hydrocarbon group; Preferred, R1 is selected from C4~C 30 Alkyl, C4-C 30 alkenyl, C6-C 30 The aryl group is preferably derived from C4 to C5. 30 alkyl; And / or, R2 is selected from H, C1 to C 10 Alkyl groups, C2-C 10 alkenyl, C6-C 10 The aryl group is preferably derived from H, C1 to C1. 10 Alkyl groups, more preferably H-, C1-C6 alkyl groups; And / or, R3 is selected from H, C1 to C 10 Alkyl groups, C2-C 10 alkenyl, C6-C 10 The aryl group is preferably derived from H, C1 to C1. 10 Alkyl groups, more preferably H-, C1-C6 alkyl groups.

4. The preparation method according to claim 3, characterized in that, The epoxy compound is selected from C2 to C3 epoxy compounds; preferably, the epoxy compound includes ethylene oxide and / or propylene oxide; And / or, the capping agent is selected from at least one of haloalkanes, organic acids, compounds containing anhydride groups, and compounds containing acyl halide groups; preferably, the capping agent includes at least one of iodomethane, iodoethane, iodopropane, iodoethylene, acetic acid, acetic anhydride, and acetyl chloride; And / or, the quaternizing agent includes at least one of sodium chloroacetate, potassium chloroacetate, sodium bromoacetate, and potassium bromoacetate.

5. The preparation method according to claim 3 or 4, characterized in that, The molar ratio of the epoxy compound to the alkyl aniline is (1-50):1, preferably (2-30):1, and more preferably (4-20):1; And / or, the molar ratio of the capping agent to alkylaniline is (0-2.6):1, preferably (2-2.4):1; And / or, the molar ratio of the quaternizing agent to alkylaniline is (1-5):

1.

6. The preparation method according to any one of claims 3-5, characterized in that, The reaction conditions for the reaction between the alkylaniline and the epoxy compound include: a reaction temperature of 100–200°C and a reaction pressure of 0–5 MPa.

7. The preparation method according to any one of claims 3-6, characterized in that, The reaction of the alkylaniline with the epoxy compound is carried out in the presence of a basic catalyst; Preferred, The alkaline catalyst includes at least one of alkali metals, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal alkoxides, and alkali metal oxides. And / or, the amount of the alkaline catalyst is 0.1 to 10 wt% of the mass of alkylaniline, preferably 0.5 to 5.0 wt%.

8. The preparation method according to any one of claims 3-7, characterized in that, The temperature of the quaternization reaction is 20–80°C; And / or, the quaternization reaction is carried out in the presence of an alkaline catalyst; preferably, the alkaline catalyst includes at least one of alkali metal, alkali metal hydroxide, alkaline earth metal hydroxide, alkali metal alkoxide, and alkali metal oxide; preferably, the molar ratio of the alkaline catalyst to the alkylaniline polyether is (0.1-5):

1.

9. An oil displacement agent comprising the alkylphenylamine polyether zwitterionic surfactant of claim 1 or 2, or the alkylphenylamine polyether zwitterionic surfactant prepared by any one of claims 3-8, and water; Preferably, the mass ratio of the alkylphenylammonium polyether zwitterionic surfactant to water is 1:(50-2000), more preferably 1:(80-500).

10. The application of the alkylphenylamine polyether zwitterionic surfactant of claim 1 or 2, or the alkylphenylamine polyether zwitterionic surfactant prepared by any one of claims 3-8, or the oil displacement agent of claim 9, in oil recovery, especially in enhanced oil recovery of heavy oil reservoirs.

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