PPO / PEO block Gemini malleable surfactant suitable for high-temperature and high-salt oil reservoir and preparation method of PPO / PEO block Gemini malleable surfactant

Abstract

The invention relates to the technical field of preparation of surfactants, in particular to a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salt oil reservoirs and a preparation method of the PPO / PEO block Gemini ductile surfactant. The preparation method comprises the following steps: by taking fatty alcohol as an initial raw material, carrying out gradual addition on the fatty alcohol, propylene oxide (PO) and ethylene oxide (EO) through a potassium hydroxide / 18-crown ether-6 catalytic system to prepare an APOnEOm intermediate; the preparation method comprises the following steps: carrying out esterification with a polyethylene glycol bismaleate connecting group, and finally sulfonating with sodium hydrogen sulfite to obtain polyethylene glycol bismaleate diester sodium sulfonate (T-APOnEOm-S). By regulating and controlling the PPO / PEO block ratio, the product has excellent temperature resistance and salt resistance, is suitable for high-temperature and high-salt oil reservoirs, has strong emulsifying capacity, can reduce the oil-water interfacial tension to 10 <-3 > mN / m level, and remarkably improves the oil recovery rate. The preparation process is mild in condition and adjustable in product performance, and has important application value in the field of tertiary oil recovery.

Description

Technical Field

[0001] The present invention relates to the technical field of surfactant preparation, and in particular to a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs and a preparation method thereof. Background Art

[0002] Surfactants are a core component of chemical flooding for enhanced oil recovery, demonstrating excellent performance in processes such as alkali-surfactant-polymer flooding (ASP) and surfactant-polymer flooding (SP). Surfactants significantly improve oil displacement efficiency and, in turn, significantly increase crude oil recovery by reducing oil-water interfacial tension, altering rock wettability, and promoting crude oil emulsification and solubilization. Compared to traditional water flooding, surfactant flooding can increase crude oil recovery by over 20%. As secondary oil recovery enters its later stages, chemical flooding technology is expanding from oilfields with reservoir temperatures <50°C and salinity <1000 mg / L to high-temperature, high-salinity reservoirs, placing higher demands on the performance of surfactants.

[0003] The most widely used anionic surfactants in the process of enhancing oil recovery in conventional oil reservoirs include sulfonates, sulfates, and carboxylates. Among them, carboxylate surfactants, due to their carboxylic acid structure, not only have the advantages of natural biodegradation and environmental friendliness, but also exhibit good foaming, wetting and emulsifying properties. However, since the carboxylate group is easily precipitated with metal ions and the chemical bond stability is poor, its solubility and salt resistance are poor and it is easy to decompose in strong acid, strong alkali and high temperature environments. The sulfate-type surfactants have a strong hydrophilic sulfate group, which exhibits excellent interfacial activity, foaming, wetting reversal and emulsification stability, but because high concentrations of salt ions will shield its charge, destroy the stability of the micelles and easily react with Ca 2+ / Mg 2+ The formation of precipitation, and the high polarity and low bond energy of the SO bond of the sulfate ester are easily hydrolyzed and inactivated under high temperature conditions, making sulfate surfactants less resistant to temperature and salt. Therefore, the development of efficient surfactants is the key to improving EOR.

[0004] Compared with other types of surfactants, sulfonate surfactants have -SO3 -Connected by chemical bond, there is rigid sulfonic acid group, higher chemical stability, also show higher interfacial activity, efficient wettability reversibility, good emulsification and solubilizing ability, stronger acid and alkali resistance and temperature resistant characteristic, can preferably meet the requirement of tertiary oil recovery technology, but, under high salt environment, the strong electrostatic interaction between salt ion and sulfonate radical can cause surfactant molecule to separate out or form insoluble precipitation, reduce its salt tolerance, be difficult to meet the mining requirement of high mineralization oil reservoir, thus limit the application of such surfactant in extreme oil reservoir environment. Therefore, conventional surfactant cannot adapt to the oil reservoir environment of high temperature and high salt, and it is urgent to develop new surfactant. For this problem, prior art (such as patent CN102040994B) proposes the solution of aminosulfonic acid type amphoteric surfactant compounding, but the compounding system still has the problems such as poor compatibility, synergistic effect uncontrollable. Summary of the Invention

[0005] The present invention aims to solve the technical problem that the existing surfactants have insufficient temperature and salt resistance during oil production, which leads to limited improvement in oil recovery rate, and to provide Gemini-type surfactants with excellent temperature and salt resistance. This surfactant can still achieve ultra-low interfacial tension (on the order of 10-3mN / m) in a 9.0% NaCl high salinity environment under high temperature conditions of 70°C. The surfactant series products developed by the present invention not only significantly improve the crude oil recovery rate, but also break through the performance bottleneck of traditional surfactants in high temperature and high salt environments, and achieve a synergistic improvement in temperature resistance and salt resistance.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs comprises the following steps:

[0008] (1) Preparation of APOnEOm: Fatty alcohol is used as a starting material and added into a polymerization reactor. Potassium hydroxide is added as a catalyst and 18-crown ether-6 is added as a complexing agent. A propoxylation reaction or a propoxylation reaction and an ethoxylation reaction are carried out to prepare fatty alcohol polyoxypropylene polyoxyethylene ether APOnEOm, wherein n is 3-30 and m is 0-30. The fatty alcohol includes any one of n-octanol, n-decanol, dodecanol, tetradecanol, and hexadecanol.

[0009] (2) Preparation of the linker: maleic anhydride and polyethylene glycol were mixed, anhydrous sodium acetate was added as a catalyst, and the mixture was heated and stirred to obtain a linker;

[0010] (3) Preparation of T-APOnEOm: The fatty alcohol polyoxypropylene polyoxyethylene ether APOnEOm and the linker are mixed, p-toluenesulfonic acid is added as a catalyst, and molecular sieves are added as a desiccant, and the mixture is stirred and reacted in a negative pressure environment to obtain polyethylene glycol bismaleate T-APOnEOm;

[0011] (4) Preparation of T-APOnEOm-S: The polyethylene glycol bismaleic acid diester T-APOnEOm is mixed with an aqueous sodium bisulfite solution, and hexadecyltrimethylammonium bromide is added as a catalyst. The mixture is stirred and reacted to obtain the target product, polyethylene glycol bismaleic acid diester sodium sulfonate, that is, a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salt oil reservoirs.

[0012] Furthermore, in step (1):

[0013] When m=0, a fatty alcohol is used as a starting material and added into a polymerization reaction kettle, potassium hydroxide is added as a catalyst, and 18-crown ether-6 is added as a complexing agent, and propylene oxide is added at 130° C.-135° C. to carry out a propoxylation reaction to prepare APOn;

[0014] When the value of m is 1-30, fatty alcohol is used as a starting raw material and added into a polymerization reaction kettle. Potassium hydroxide is added as a catalyst and 18-crown ether-6 is added as a complexing agent. Propylene oxide is added at 130° C.-135° C. to carry out a propoxylation reaction. Ethylene oxide is added at 125° C.-130° C. to carry out an ethoxylation reaction to prepare fatty alcohol polyoxypropylene polyoxyethylene ether APOnEOm.

[0015] Furthermore, the mass of the added potassium hydroxide is 3‰-5‰ of the total mass of the fatty alcohol and propylene oxide;

[0016] The molar ratio of the added 18-crown ether-6 to the added potassium hydroxide is (1.00-2.00):1.00;

[0017] The molar ratio of the added propylene oxide to the fatty alcohol is (3.00-30.00):1.00;

[0018] The molar ratio of the added ethylene oxide to the fatty alcohol is (0.00-30.00):1.00.

[0019] Furthermore, step (2) is specifically as follows: maleic anhydride and polyethylene glycol are added to a flask at a molar ratio of (2.00-3.00):1.00, anhydrous sodium acetate is added as a catalyst, and the mixture is stirred at 90-100° C. for 1.0-1.2 hours to obtain a linker;

[0020] The mass of the added anhydrous sodium acetate is 1.0%-2.0% of the total mass of maleic anhydride and polyethylene glycol.

[0021] Furthermore, step (3) is specifically as follows: adding the fatty alcohol polyoxypropylene polyoxyethylene ether APOnEOm and the linking group in a molar ratio of (2.00-3.00): 1.00 into a flask, adding p-toluenesulfonic acid as a catalyst, and adding molecular sieves as a desiccant, stirring at 140-150° C. and in an environment of -0.7 MPa to -1.0 MPa for 7-8 hours to obtain polyethylene glycol bismaleate T-APOnEOm;

[0022] Wherein, the amount of p-toluenesulfonic acid added is 1.0%-3.0% of the total mass of the linker and APOnEOm;

[0023] Furthermore, the molecular sieve uses any one or more of 3A molecular sieve, 4A molecular sieve and 5A molecular sieve.

[0024] Furthermore, step (4) is specifically as follows:

[0025] The polyethylene glycol bismaleic acid diester T-APOnEOm prepared in step (3) and a sodium bisulfite aqueous solution are added to a flask at a molar ratio of 1.00:(2.00-4.00), cetyltrimethylammonium bromide is added as a catalyst, and the mixture is stirred at 100-110° C. for 12-14 hours to prepare polyethylene glycol bismaleic acid diester sodium sulfonate T-APOnEOm-S;

[0026] Wherein, the concentration of the sodium bisulfite aqueous solution is 30.0-40.0 wt%.

[0027] The added amount of hexadecyltrimethylammonium bromide is 2.0%-4.0% of the mass of polyethylene glycol bismaleic acid diester T-APOnEOm.

[0028] The invention relates to a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs. In the surfactant polyethylene glycol sodium bismaleate sulfonate T-APOnEOm-S, n is 3-30 and m is 0-30.

[0029] Furthermore, the surfactant polyethylene glycol sodium bismaleate sulfonate T-APOnEOm-S can stably maintain the oil-water interfacial tension at the level of 10-3 mN / m in brine containing up to 9.0 wt% NaCl; the surfactant polyethylene glycol sodium bismaleate sulfonate T-APOnEOm-S can maintain the oil-water interfacial tension at the level of 10-3 mN / m at 120°C and 9.0 wt% NaCl. -2mN / m, the oil-water interfacial tension was maintained at 10 at 70 °C and 9.0 wt% NaCl. -3 The order of magnitude is mN / m.

[0030] The invention relates to an application of a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs, and the surfactant is used for recovery of high-temperature and high-salinity oil reservoirs.

[0031] Beneficial effects of the present invention:

[0032] (1) The present invention provides a method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs. The PPO-PEO block significantly improves the temperature and salt resistance of the surfactant through the synergistic effect of hydrophobicity and hydrophilicity: the PPO block forms a compact micelle structure at high temperature by virtue of the hydrophobicity and steric hindrance effect of its methyl side chain, enhancing thermal stability and blocking salt ion penetration; at the same time, the PEO block forms a hydration layer through its flexible chain, which not only maintains the hydrophilicity of the molecule but also wraps the anionic groups through the curled structure, effectively shielding the electrostatic effect of high-valent salt ions. The dynamic balance between the two enables the molecule to maintain structural integrity and solubility in a high-temperature and high-salinity environment, thereby exhibiting excellent temperature and salt resistance.

[0033] (2) The present invention provides the preparation of a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs. The surfactant has excellent salt tolerance and can stably maintain the oil-water interfacial tension at an ultra-low level of 10-3 mN / m in brine containing up to 9.0% NaCl.

[0034] (3) The present invention provides a preparation of a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs, which has excellent temperature resistance and can maintain the oil-water interfacial tension at 10 at high temperatures and salt concentrations. - 2 The mN / m level can even reach 10 -3 mN / m level. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The figure is a flow chart of the preparation method of PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs.

[0036] Figure 2a This is the H NMR spectrum analysis of T-APO10-S prepared in Example 1;

[0037] Figure 2b This is the H NMR spectrum analysis of T-APO10EO2-S prepared in Example 2;

[0038] Figure 2c This is the H NMR spectrum analysis of T-APO10EO4-S prepared in Example 3;

[0039] Figure 2d This is the H NMR analysis of T-APO10EO6-S prepared in Example 4;

[0040] Figure 2e This is the H NMR spectrum analysis of T-APO10EO8-S prepared in Example 5;

[0041] Figure 2f This is the H NMR spectrum analysis of T-APO10EO10-S prepared in Example 6;

[0042] Figure 3 This is the Fourier infrared spectroscopy analysis of T-APO10EOm-S prepared in Example 1-6. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] The preparation method of PPO / PEO block Gemini ductile surfactant suitable for high temperature and high salinity oil reservoirs, such as Figure 1 As shown. It includes the following steps:

[0045] (1) Preparation of APOnEOm: Fatty alcohol is used as a starting material and added into a polymerization reactor. Potassium hydroxide is added as a catalyst and 18-crown ether-6 is added as a complexing agent. A propoxylation reaction or a propoxylation reaction and an ethoxylation reaction are carried out to prepare fatty alcohol polyoxypropylene polyoxyethylene ether APOnEOm, where n is 3-30 and m is 0-30. In the present invention, the fatty alcohol includes any one of n-octanol, n-decanol, dodecanol, tetradecanol, and hexadecanol.

[0046] Specifically, when m=0, a fatty alcohol is used as a starting material and added into a polymerization reaction kettle, potassium hydroxide is added as a catalyst, and 18-crown ether-6 is added as a complexing agent, and propylene oxide is added at 130° C.-135° C. to carry out a propoxylation reaction; APOn is prepared;

[0047] When the value of m is 1-30, fatty alcohol is used as a starting raw material and added into a polymerization reaction kettle. Potassium hydroxide is added as a catalyst and 18-crown ether-6 is added as a complexing agent. Propylene oxide is added at 130° C.-135° C. to carry out a propoxylation reaction. Ethylene oxide is added at 125° C.-130° C. to carry out an ethoxylation reaction to prepare fatty alcohol polyoxypropylene polyoxyethylene ether APOnEOm.

[0048] The mass of potassium hydroxide added is 3‰-5‰ of the total mass of fatty alcohol and propylene oxide;

[0049] The molar ratio of the added 18-crown ether-6 to the added potassium hydroxide is (1.00-2.00):1.00;

[0050] The molar ratio of the added propylene oxide to the fatty alcohol is (3.00-30.00):1.00;

[0051] The molar ratio of the added ethylene oxide to the fatty alcohol is (0.00-30.00):1.00.

[0052] (2) Preparation of a linker: maleic anhydride and polyethylene glycol were added to a flask at a molar ratio of (2.00-3.00):1.00, anhydrous sodium acetate was added as a catalyst, and the mixture was stirred at 90-100° C. for 1.0-1.2 hours to obtain a linker;

[0053] The mass of the added anhydrous sodium acetate is 1.0%-2.0% of the total mass of maleic anhydride and polyethylene glycol.

[0054] (3) Preparation of T-APOnEOm: The fatty alcohol polyoxypropylene polyoxyethylene ether APOnEOm and the linker are added to a flask at a molar ratio of (2.00-3.00):1.00, p-toluenesulfonic acid is added as a catalyst, and molecular sieves are added as a desiccant. The mixture is stirred at 140-150° C. and in an environment of -0.7 MPa to -1.0 MPa for 7-8 hours to obtain polyethylene glycol bismaleate T-APOnEOm;

[0055] The amount of p-toluenesulfonic acid added is 1.0%-3.0% of the total mass of the linker and APOnEOm; and the molecular sieve is any one or more of 3A molecular sieve, 4A molecular sieve and 5A molecular sieve.

[0056] (4) Preparation of T-APOnEOm-S: The polyethylene glycol bismaleic acid diester T-APOnEOm prepared in step (3) and a sodium bisulfite aqueous solution were added to a flask at a molar ratio of 1.00:(2.00-4.00), and hexadecyltrimethylammonium bromide was added as a catalyst. The mixture was stirred at 100-110° C. for 12-14 hours to prepare polyethylene glycol bismaleic acid diester sodium sulfonate T-APOnEOm-S.

[0057] Wherein, the concentration of the sodium bisulfite aqueous solution is 30.0-40.0 wt%.

[0058] The added amount of hexadecyltrimethylammonium bromide is 2.0%-4.0% of the mass of polyethylene glycol bismaleic acid diester T-APOnEOm.

[0059] The following are specific embodiments:

[0060] Example 1: A method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs, the method comprising:

[0061] S1. Take 120.00g of dodecanol as the starting material and add it to a polymerization reactor. At the same time, add 1.50g of potassium hydroxide as a catalyst and 7.07g of 18-crown ether-6 as a complexing agent. Add 374.20g of propylene oxide at 130°C to carry out a propoxylation reaction to polymerize APO10, the structural formula of which is as follows:

[0062]

[0063] S2. 30.00 g of maleic anhydride and 21.37 g of triethylene glycol were added to a flask, and 0.54 g of anhydrous sodium acetate was added as a catalyst. The mixture was stirred at 95° C. for 1 hour. The reaction was accelerated by heating and introducing a catalyst to obtain a linker. The structural formula of the linker is as follows:

[0064]

[0065] S3. 60.00 g of APO10 and 13.23 g of a linker were added to a flask, 1.46 g of p-toluenesulfonic acid was added as a catalyst, and molecular sieves were added as a water scavenger. The mixture was stirred at 145° C. under negative pressure for 8 hours to obtain T-APO10. The structural formula of T-APO10 is as follows:

[0066]

[0067] S4. 30.00 g of T-APO10 and 14.52 g of a 35% aqueous sodium bisulfite solution were added to a flask, 0.90 g of hexadecyltrimethylammonium bromide was added as a catalyst, and the mixture was stirred at 104 ° C for 14 hours to obtain the final product T-APO10-S, which has the following structural formula:

[0068]

[0069] Example 2: A method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs, the method comprising:

[0070] S1. Take 120.00g of dodecanol as the starting material and add it to a polymerization reactor. At the same time, add 1.50g of potassium hydroxide as a catalyst and 7.07g of 18-crown ether-6 as a complexing agent. Add 374.20g of propylene oxide at 130°C to carry out a propoxylation reaction. Then, add 56.77g of ethylene oxide at 125°C to carry out an ethoxylation reaction to polymerize APO10EO2. The structural formula of APO10EO2 is as follows:

[0071]

[0072] S2. 30.00 g of maleic anhydride and 21.37 g of triethylene glycol were added to a flask, and 0.54 g of anhydrous sodium acetate was added as a catalyst. The mixture was stirred at 95° C. for 1 hour. The reaction was accelerated by heating and introducing a catalyst to obtain a linker. The linker structure is as follows:

[0073]

[0074] S3. 60.00 g of APO10EO2 and 11.87 g of a linker were added to a flask, 1.44 g of p-toluenesulfonic acid was added as a catalyst, and molecular sieves were added as a water scavenger. The mixture was stirred at 145 ° C under negative pressure for 8 hours to obtain T-APO10EO2. The structural formula of the T-APO10EO2 reactant is as follows:

[0075]

[0076] S4. 30.00 g of T-APO10EO2 and 13.26 g of a 35% aqueous sodium bisulfite solution were added to a flask, 0.90 g of hexadecyltrimethylammonium bromide was added as a catalyst, and the mixture was stirred at 104 ° C for 14 hours to give the final product T-APO10EO2-S. The structural formula of T-APO10EO2-S is as follows:

[0077]

[0078] Example 3: A method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs, the method comprising:

[0079] S1. Take 120.00g of tetradecanol as a starting material and add it to a polymerization reactor. At the same time, add 1.40g of potassium hydroxide as a catalyst and 6.60g of 18-crown ether-6 as a complexing agent. Add 325.23g of propylene oxide at 130°C to carry out a propoxylation reaction. Then, add 99.00g of ethylene oxide at 125°C to carry out an ethoxylation reaction to polymerize APO10EO4. The structural formula of APO10EO4 is as follows:

[0080]

[0081] S2. 30.00 g of maleic anhydride and 21.37 g of triethylene glycol were added to a flask, and 0.54 g of anhydrous sodium acetate was added as a catalyst. The mixture was stirred at 95° C. for 1 hour. The reaction was accelerated by heating and introducing a catalyst to obtain a linker. The structural formula of the linker reactant is as follows:

[0082]

[0083] S3. 60.00 g of APO10EO4 and 8.53 g of a linker were added to a flask, 1.37 g of p-toluenesulfonic acid was added as a catalyst, and molecular sieves were added as a water scavenger. The mixture was stirred at 145 ° C under negative pressure for 8 hours to obtain T-APO10EO4. The structural formula of T-APO10EO4 is as follows:

[0084]

[0085] S4. 30.00 g of T-APO10EO4 and 11.89 g of a 35% aqueous sodium bisulfite solution were added to a flask, 0.90 g of hexadecyltrimethylammonium bromide was added as a catalyst, and the mixture was stirred at 104 ° C for 14 hours to give the final product T-APO10EO4-S. The structural formula of T-APO10EO4-S is as follows:

[0086]

[0087] Example 4: A method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs, the method comprising:

[0088] S1. Take 120.00g of tetradecanol as a starting material and add it to a polymerization reactor. At the same time, add 1.40g of potassium hydroxide as a catalyst and 6.60g of 18-crown ether-6 as a complexing agent. Add 325.23g of propylene oxide at 130°C to carry out a propoxylation reaction. Then, add 149.00g of ethylene oxide at 125°C to carry out an ethoxylation reaction to polymerize APO10EO6. The structural formula of APO10EO6 is as follows:

[0089]

[0090] S2. 30.00 g of maleic anhydride and 21.37 g of triethylene glycol were added to a flask, and 0.54 g of anhydrous sodium acetate was added as a catalyst. The mixture was stirred at 95° C. for 1 hour. The reaction was accelerated by heating and introducing a catalyst to obtain a linker. The linker structure is as follows:

[0091]

[0092] S3. 60.00 g of APO10EO6 and 7.86 g of a linker were added to a flask, 1.40 g of p-toluenesulfonic acid was added as a catalyst, and molecular sieves were added as a water scavenger. The mixture was stirred at 145 ° C under negative pressure for 8 hours to obtain T-APO10EO6. The structural formula of T-APO10EO6 is as follows:

[0093]

[0094] S4. 30.00 g of T-APO10EO6 and 11.03 g of a 35% aqueous sodium bisulfite solution were added to a flask, 0.90 g of hexadecyltrimethylammonium bromide was added as a catalyst, and the mixture was stirred at 104 ° C for 12 hours to give the final product T-APO10EO6-S. The structural formula of T-APO10EO6-S is as follows:

[0095]

[0096] Example 5: A method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs, the method comprising:

[0097] S1. 120g of hexadecanol was added as a starting material to a polymerization reactor, along with 1.30g of potassium hydroxide as a catalyst and 6.15g of 18-crown ether-6 as a complexing agent. 287.60g of propylene oxide was added at 130°C for propoxylation, followed by 227.10g of ethylene oxide at 125°C for ethoxylation to form APO10EO8. The structural formula of APO10EO8 is as follows:

[0098]

[0099] S2. 30.00 g of maleic anhydride and 21.37 g of triethylene glycol were added to a flask, and 0.54 g of anhydrous sodium acetate was added as a catalyst. The mixture was stirred at 95° C. for 1 hour. The reaction was accelerated by heating and introducing a catalyst to obtain a linker. The linker structure is as follows:

[0100]

[0101] S3. 60.00 g of APO10EO8 and 7.10 g of a linker were added to a flask, 1.35 g of p-toluenesulfonic acid was added as a catalyst, and molecular sieves were added as a water scavenger. The mixture was stirred at 145 ° C under negative pressure for 8 hours to obtain T-APO10EO8. The structural formula of T-APO10EO8 is as follows:

[0102]

[0103] S4. 30.00 g of T-APO10EO8 and 10.10 g of a 35% aqueous sodium bisulfite solution were added to a flask, 0.90 g of hexadecyltrimethylammonium bromide was added as a catalyst, and the mixture was stirred at 104 ° C for 14 hours to obtain the final product T-APO10EO8-S. The structural formula of T-APO10EO8-S is as follows:

[0104]

[0105] Example 6: A method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs, the method comprising:

[0106] S1. 120 g of hexadecanol was added as a starting material to a polymerization reactor, along with 1.30 g of potassium hydroxide as a catalyst and 6.15 g of 18-crown ether-6 as a complexing agent. 287.60 g of propylene oxide was added at 130 ° C for propoxylation reaction, followed by 218.20 g of ethylene oxide at 125 ° C for ethoxylation reaction to polymerize APO10EO10. The structural formula of APO10EO10 is as follows:

[0107]

[0108] S2. 30.00 g of maleic anhydride and 21.37 g of triethylene glycol were added to a flask, and 0.54 g of anhydrous sodium acetate was added as a catalyst. The mixture was stirred at 95° C. for 1 hour. The reaction was accelerated by heating and introducing a catalyst to obtain a linker. The linker structure is as follows:

[0109]

[0110] S3. 60.00 g of APO10EO10 and 6.60 g of a linker were added to a flask, 1.34 g of p-toluenesulfonic acid was added as a catalyst, and molecular sieves were added as a water scavenger. The mixture was stirred at 145 ° C under negative pressure for 8 hours to obtain T-APO10EO10. The structural formula of T-APO10EO10 is as follows:

[0111]

[0112] S4. 30.00 g of T-APO10EO10 and 9.45 g of a 35% aqueous solution of sodium bisulfite were added to a flask, 0.90 g of hexadecyltrimethylammonium bromide was added as a catalyst, and stirred at 104 ° C for 14 hours to give the final product T-APO10EO10-S, T-APO10EO10-S structural formula:

[0113]

[0114] As shown in Figure 2-3, the target product of Example 1-6 was subjected to nuclear magnetic resonance hydrogen spectrum analysis and Fourier transform infrared spectrum analysis, confirming that the synthesized product is the target product. The analysis of Figure 2 is as follows: the characteristic signal observed at a is attributed to the -(CH3)- group of the fatty alcohol, the characteristic signal observed at b is attributed to the -(CH3)- and -(CH2)- groups and -(CH2(CH3))- groups of the hydrophobic part of the PPO block; the chemical shift detected at c is determined to correspond to the -(CH2-CH2-O)- group; the obvious peak at d is attributed to the -CH(NaHSO3)- group; and the peak at e is attributed to the -(CH-C=O)- group.

[0115] Salt tolerance test: A precisely prepared aqueous solution containing 0.3wt% surfactant was added, and the salt concentration was adjusted by adding varying amounts of NaCl. The dynamic interfacial tension between the solution and liquid paraffin was measured using a spinning drop interfacial tension meter at a constant temperature of 45°C. This evaluated the ability and stability to achieve ultra-low interfacial tension under varying salinity conditions.

[0116] Temperature resistance test: A precisely prepared aqueous solution containing 0.3wt% surfactant was added, and the salt concentration was adjusted to 9.0% by adding a certain amount of NaCl. The dynamic interfacial tension between the solution and liquid paraffin was measured using a spinning drop interfacial tension meter at different temperatures to evaluate the ability and stability to achieve ultra-low interfacial tension under different temperature conditions.

[0117] Table 1 Oil-water interfacial tension of surfactants prepared in Examples 1-6 at different salt concentrations at 45°C

[0118]

[0119] The results of salt tolerance testing are shown in Table 1. The IFT of the T-APOnEm-S surfactant-liquid paraffin-brine system exhibited a regular pattern with salinity. With increasing NaCl concentration, the IFT first decreased and then increased, with all synthesized T-APOnEm-S surfactants reaching 10-3 mN / m. Notably, T-APO10EO4-S was able to stably maintain an ultra-low oil-water interfacial tension of 10-3 mN / m in 3%-7% NaCl, while T-APO10EO8-S also exhibited excellent interfacial activity in 7%-11% NaCl, maintaining an oil-water interfacial tension level of 10-3 mN / m. These results demonstrate the stable temperature resistance of T-APOnEOm-S.

[0120] Table 2 Interfacial tension of surfactants prepared in Examples 1-6 at different temperatures at 9% NaCl

[0121]

[0122] The results of the temperature resistance tests are shown in Table 2. The results show that the IFT of T-APOnEOm-S (n=10; m=0, 2, 4, 6) increases monotonically with increasing temperature, while the IFT of T-APOnEOm-S (n=10; m=8, 10) decreases first and then increases. At 70°C, T-APO10EO8-S and T-APO10EO10-S maintain an ultra-low oil-water interfacial tension of 10-3 mN / m, while T-APO10EO10-S maintains a constant 10-2 mN / m even at 120°C. These results demonstrate the stable temperature resistance of T-APOnEOm-S.

[0123] The Gemini sulfonate surfactant containing PPO-PEO blocks provided by the present invention exhibits significant advantages due to its intramolecular collaborative design: its PPO segment constructs a high-temperature resistant hydrophobic skeleton, the PEO segment enhances solubility, and the unique double-chain Gemini structure further achieves extremely low critical micelle concentration, ultra-low interfacial tension and high-temperature and high-salt stability. It can integrate multiple functions without the need for compounding, avoiding performance fluctuations, cost increases and environmental risks caused by compounding, and providing a more efficient and stable monomer solution for harsh oil reservoir conditions.

[0124] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salt oil reservoirs, characterized in that: The following steps are involved: (1) Preparation of APOnEOm: Fatty alcohol is used as a starting material and added into a polymerization reactor. Potassium hydroxide is added as a catalyst and 18-crown ether-6 is added as a complexing agent. A propoxylation reaction or a propoxylation reaction and an ethoxylation reaction are carried out to prepare fatty alcohol polyoxypropylene polyoxyethylene ether APOnEOm, where n is 3-30 and m is 0-30. (2) Preparation of the linker: maleic anhydride and polyethylene glycol were mixed, anhydrous sodium acetate was added as a catalyst, and the mixture was heated and stirred to obtain a linker; (3) Preparation of T-APOnEOm: The fatty alcohol polyoxypropylene polyoxyethylene ether APOnEOm and the linker are mixed, p-toluenesulfonic acid is added as a catalyst, and molecular sieves are added as a desiccant, and the mixture is stirred and reacted in a negative pressure environment to obtain polyethylene glycol bismaleate T-APOnEOm; (4) Preparation of T-APOnEOm-S: The polyethylene glycol bismaleic acid diester T-APOnEOm is mixed with an aqueous sodium bisulfite solution, and hexadecyltrimethylammonium bromide is added as a catalyst. The mixture is stirred and reacted to obtain the target product, polyethylene glycol bismaleic acid diester sodium sulfonate, that is, a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salt oil reservoirs.

2. The method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salt oil reservoirs according to claim 1, characterized in that: In step (1): When m=0, a fatty alcohol is used as a starting material and added into a polymerization reaction kettle, potassium hydroxide is added as a catalyst, and 18-crown ether-6 is added as a complexing agent, and propylene oxide is added at 130° C.-135° C. to carry out a propoxylation reaction to prepare APOn; When the value of m is 1-30, fatty alcohol is used as a starting raw material and added into a polymerization reaction kettle. Potassium hydroxide is added as a catalyst and 18-crown ether-6 is added as a complexing agent. Propylene oxide is added at 130° C.-135° C. to carry out a propoxylation reaction. Then, ethylene oxide is added at 125° C.-130° C. to carry out an ethoxylation reaction to prepare fatty alcohol polyoxypropylene polyoxyethylene ether APOnEOm.

3. The method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salt oil reservoirs according to claim 2, characterized in that: The mass of potassium hydroxide added is 3‰-5‰ of the total mass of fatty alcohol and propylene oxide; The molar ratio of the added 18-crown ether-6 to the added potassium hydroxide is (1.00-2.00):1.00; The molar ratio of the added propylene oxide to the fatty alcohol is (3.00-30.00):1.00; The molar ratio of the added ethylene oxide to the fatty alcohol is (0.00-30.00):1.

00.

4. The method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salt oil reservoirs according to claim 1, characterized in that: Step (2) is specifically as follows: maleic anhydride and polyethylene glycol are added to a flask at a molar ratio of (2.00-3.00):1.00, anhydrous sodium acetate is added as a catalyst, and the mixture is stirred at 90-100° C. for 1.0-1.2 hours to obtain a linker; The mass of the added anhydrous sodium acetate is 1.0%-2.0% of the total mass of maleic anhydride and polyethylene glycol.

5. The method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salt oil reservoirs according to claim 1, characterized in that: Step (3) is specifically as follows: adding the fatty alcohol polyoxypropylene polyoxyethylene ether APOnEOm and the linking group in a molar ratio of (2.00-3.00):1.00 into a flask, adding p-toluenesulfonic acid as a catalyst, and adding molecular sieves as a dehydrating agent, stirring at 140-150° C. and in an environment of -0.7 MPa to -1.0 MPa for 7-8 hours to obtain polyethylene glycol bismaleate T-APOnEOm; The amount of p-toluenesulfonic acid added is 1.0%-3.0% of the total mass of the linker and APOnEOm.

6. The method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salt oil reservoirs according to claim 5, characterized in that: The molecular sieve may be any one or more of 3A molecular sieve, 4A molecular sieve and 5A molecular sieve.

7. The method for preparing a PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salt oil reservoirs according to claim 1, characterized in that: Step (4) is specifically as follows: The polyethylene glycol bismaleic acid diester T-APOnEOm prepared in step (3) and a sodium bisulfite aqueous solution are added to a flask at a molar ratio of 1.00:(2.00-4.00), cetyltrimethylammonium bromide is added as a catalyst, and the mixture is stirred at 100-110° C. for 12-14 hours to prepare polyethylene glycol bismaleic acid diester sodium sulfonate T-APOnEOm-S; Wherein, the concentration of the sodium bisulfite aqueous solution is 30.0-40.0 wt%. The added amount of hexadecyltrimethylammonium bromide is 2.0%-4.0% of the mass of polyethylene glycol bismaleic acid diester T-APOnEOm.

8. A PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs, prepared by the method according to any one of claims 1 to 7, characterized in that: In the surfactant polyethylene glycol sodium bismaleate sulfonate T-APOnEOm-S, n is 3-30, and m is 0-30.

9. The PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs according to claim 6, characterized in that: The surfactant polyethylene glycol sodium bismaleate sulfonate T-APOnEOm-S can stably maintain the oil-water interfacial tension at the level of 10-3 mN / m in saline with a NaCl content of up to 9.0 wt%. The surfactant polyethylene glycol sodium bismaleate sulfonate T-APOnEOm-S can stably maintain the oil-water interfacial tension at the level of 10-3 mN / m in saline with a NaCl content of up to 9.0 wt%. -2 mN / m, the oil-water interfacial tension was maintained at 10 at 70 °C and 9.0 wt% NaCl. - 3 The order of magnitude is mN / m.

10. The use of the PPO / PEO block Gemini ductile surfactant suitable for high-temperature and high-salinity oil reservoirs according to any one of claims 6-7, characterized in that: The surfactant is used for recovery of high-temperature and high-salinity oil reservoirs.

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