Preparation method of fatty amine polyester ether surfactant and composite ionic oil-displacing agent of fatty amine polyester ether surfactant

Abstract

The invention relates to a preparation method of an aliphatic amine polyester ether surfactant and a compound ionic oil-displacing agent thereof, and relates to the technical field of oil field chemicals, the preparation method comprises the following steps: taking aliphatic amine as a raw material, and carrying out ring opening polymerization on the aliphatic amine and ethylene carbonate at a certain temperature under the action of a catalyst to prepare an aliphatic amine polyester ether nonionic surfactant; and compounding the fatty amine polyester ether nonionic surfactant with an anionic surfactant, a cationic surfactant, a phase solvent and water according to a certain proportion to prepare the composite ionic oil displacement agent. The fatty amine polyester ether and the composite ionic oil-displacing agent thereof are superior to a single naphthenic acid amide polyether ester sulfonate anionic oil-displacing agent in the aspects of synergistic effect, stability, salt resistance, hard water resistance, adsorption resistance, interfacial tension stability and binary system oil-displacing performance.

Description

Technical Field

[0001] This invention pertains to oilfield chemicals, and in particular relates to a method for preparing a fatty amine polyester ether surfactant and its composite ionic oil displacement agent. Background Technology

[0002] Ternary composite flooding systems (polymer + surfactant + alkali) are an important development technology in the field of chemical flooding in oilfields. A series of pilot field tests have been conducted in Daqing Oilfield, effectively improving crude oil recovery rates. However, some problems have arisen with the large-scale industrial application of ternary composite flooding. In particular, the use of alkali can cause the dispersion and migration of formation clay, leading to a decrease in formation permeability. It also brings a series of problems such as complex on-site construction processes, reduced production well production capacity, reservoir and wellbore scaling, and shortened pump inspection cycles. The presence of alkali also significantly reduces polymer viscosity, and more importantly, reduces the viscoelasticity of the polymer. Unfavorable mobility ratios can lead to viscous fingering, greatly reducing the swept volume and resulting in oil recovery losses. Simultaneously, the presence of alkali can cause severe emulsification of the produced fluid, not only affecting well productivity but also significantly increasing the difficulty and cost of demulsification and dehydration in the surface system and wastewater treatment. These adverse factors severely restrict the further application of ternary composite flooding technology.

[0003] To avoid these adverse factors, the development and promotion of alkali-free binary composite oil displacement systems (polymer + surfactant) is imperative. Binary composite oil displacement systems enhance oil recovery by utilizing the viscoelasticity of the polymer and the ultra-low interfacial tension of the surfactant without the addition of alkali. Due to the absence of alkali in the system, viscoelasticity is significantly increased; according to capillary number theory, the interfacial tension is maintained at around 10. -2 When the oil recovery rate is below the mN / m level, the effect of improving oil recovery is still no less than that of ternary composite flooding. However, precisely because there is no alkali in the system, the interfacial tension between crude oil and water often fails to meet requirements, thus affecting the oil displacement effect. Therefore, the development of surfactants with high interfacial activity, temperature and salt resistance, and low adsorption loss is of great significance. At the same time, with the increasing requirements for environmental protection, the research and application of green and environmentally friendly surfactants have received more attention. In addition, optimizing production processes and formulations to reduce the production cost of surfactants is also key to improving the economic benefits and promoting the application of binary composite flooding technology.

[0004] Currently, in tertiary oil recovery chemical flooding technology, the commonly used nonionic surfactants in binary composite flooding systems mainly include fatty alcohol polyoxyethylene ethers, fatty amine polyoxyethylene ethers, alkylphenol polyoxyethylene ethers, fatty acid polyoxyethylene esters, Pluronic series (polyoxyethylene-polyoxypropylene block copolymers), and other polyoxyethylene ether nonionic surfactants, as well as composite flooding agents that combine polyoxyethylene ether nonionic surfactants with other types of surfactants.

[0005] Polyoxyethylene ether nonionic surfactants are synthesized by ring-opening polymerization of ethylene oxide with compounds containing active hydrogen (such as fatty alcohols, alkylphenols, and fatty amines). For example, patent publication number CN111423572A, "A method for preparing octadecyl fatty amine polyoxyethylene ether," uses octadecyl fatty amine and ethylene oxide as the main raw materials. However, ethylene oxide is flammable, explosive, toxic, and irritating, leading to high costs for transportation, storage, and use. Long-term exposure can also harm human health. Furthermore, the ring-opening polymerization of ethylene oxide requires high pressure resistance and airtightness of equipment, and the process is relatively complex. These problems not only increase production costs and operational difficulty but also limit its application in chemical displacement technology.

[0006] Furthermore, composite oil displacement agents that combine polyoxyethylene ether nonionic surfactants with other types of surfactants, such as patent publication number CN113583648A "A fatty amine polyoxyethylene ether surfactant for enhancing oil recovery and its preparation method," are prepared by compounding fatty amine polyoxyethylene ether nonionic surfactants, sodium petroleum sulfonate, and industrial sodium chloride. On the one hand, the fatty amine polyoxyethylene ether nonionic surfactant in this patented formula has a relatively high final cost due to its synthesis method. On the other hand, this patented formula contains a high concentration of sodium. + and Cl - Ions readily form a strong electrolyte environment, accelerating the electrochemical corrosion of metal equipment and pipelines. Furthermore, this patented technology requires combination with alkalis to achieve ultra-low interfacial tension and application in composite oil displacement systems. Therefore, the cost-effectiveness advantage of this patented technology still has certain limitations.

[0007] In summary, superior performance, environmental friendliness, and low cost are key to the development of binary composite flooding surfactant technology. Furthermore, the synergistic properties of surfactants with polymer systems, high interfacial activity, temperature and salt resistance, and low adsorption loss are of great practical significance for the application of tertiary oil recovery chemical flooding technology. Summary of the Invention

[0008] The present invention aims to overcome the shortcomings of the prior art and provides a method for preparing a fatty amine polyester ether surfactant and its composite ionic oil displacement agent.

[0009] The fatty amine polyester ether surfactant of the present invention is a nonionic surfactant, and its structural formula is as follows:

[0010]

[0011] In the above structural formula:

[0012] m represents the degree of polymerization of the carbonate group in the fatty amine polyester ether surfactant molecule, and m is any integer from 1 to 10;

[0013] n represents the degree of polymerization of the ethoxy group in the fatty amine polyester ether surfactant molecule, and n is any integer from 1 to 10;

[0014] The sum of m+n is any integer from 2 to 20;

[0015] R represents the C12-18 alkyl group in the fatty amine polyester ether surfactant molecule.

[0016] The preparation method of the fatty amine polyester ether surfactant of the present invention is achieved by the following steps: using fatty amine as raw material, the fatty amine polyester ether surfactant is obtained by ring-opening polymerization with ethylene carbonate under the action of potassium hydroxide catalyst at a certain temperature.

[0017] The fatty amine is a C12-18 alkyl primary amine;

[0018] The amount of potassium hydroxide catalyst added is 5-10 wt.‰ of the total weight of the fatty amine and ethylene carbonate;

[0019] The molar ratio of the fatty amine to ethylene carbonate is 1:4 to 40.

[0020] As a further improvement of the present invention, the fatty amine is an alkyl C18 octadecyl primary amine.

[0021] As a further improvement of the present invention, the amount of potassium hydroxide catalyst added is preferably 8 wt.‰ of the total weight of fatty amine and ethylene carbonate.

[0022] The composite ionic oil displacement agent prepared using the above-mentioned fatty amine polyester ether surfactant is obtained from the following components in weight percentage:

[0023] The fatty amine polyester ether surfactant has a weight percentage of 10–20 wt.%.

[0024] The weight percentage of the naphthenic acid amide polyether ester sulfonate anionic surfactant is 10-20 wt.%.

[0025] The alkyltrimethylammonium sulfate cationic surfactant has a weight percentage of 1–10 wt.%.

[0026] The solvent weight percentage is 10-15 wt.%.

[0027] The remainder is water.

[0028] As a further improvement of the present invention, the fatty amine polyester ether surfactant is preferably 15 wt.% by weight.

[0029] As a further improvement of the present invention, the weight percentage of the naphthenic acid amide polyether ester sulfonate anionic surfactant is preferably 15 wt.%.

[0030] As a further improvement of the present invention, the alkyltrimethylammonium sulfate cationic surfactant has the following structural formula:

[0031] RN(CH3)3OSO3CH3

[0032] In the above structural formula: R represents the C12-18 alkyl group in the alkyltrimethylammonium sulfate cationic surfactant molecule.

[0033] As a further improvement of the present invention, the alkyltrimethyl methyl sulfate ammonium is preferably octadecyltrimethyl methyl sulfate ammonium with a C18 alkyl group, and the weight percentage is 5 wt.%.

[0034] As a further improvement of the present invention, the preferred solvent is ethylene glycol monobutyl ether, with a weight percentage of 10 wt.%. Ethylene glycol monobutyl ether is an ether-alcohol solvent that possesses both hydrophilic and lipophilic properties. The addition of the solvent can enhance the stability and synergistic effect of the composite ionic oil displacement agent, while effectively promoting the emulsification and dispersion performance of the composite ionic oil displacement agent between the water and oil phases, thereby maximizing the oil displacement efficiency of the composite ionic oil displacement agent.

[0035] The method for preparing the above-mentioned composite ionic oil displacement agent is achieved through the following steps: ethylene glycol monobutyl ether, water, fatty amine polyester ether surfactant, and naphthenic acid amide polyether ester sulfonate anionic surfactant are added sequentially to a stainless steel reactor according to the formula ratio in parts by weight, and stirring is started to dissolve for 30 minutes; after the solution is homogenized, alkyl trimethyl methyl sulfate ammonium cationic surfactant is added to the reactor, and stirring is continued to dissolve for 30 minutes. After the solution is homogenized, the composite ionic oil displacement agent product is obtained.

[0036] The naphthenic acid amide polyether ester sulfonate anionic surfactant described in this invention is preferably the naphthenic acid amide polyether ester sulfonate ultra-low interfacial tension surfactant with a patent granted by Daqing Fujie Chemical Co., Ltd. For the synthesis method, please refer to patent CN115851281A "An ultra-low interfacial tension surfactant of naphthenic acid amide polyether ester sulfonate and its preparation method".

[0037] The fatty amine polyester ether surfactant of the present invention has a simple production process, is safe and environmentally friendly; the composite ionic oil displacement agent prepared by using this surfactant can enhance the interfacial activity, hard water resistance, and salt resistance of single ionic surfactants, and improve emulsification and dispersion capabilities. Attached Figure Description

[0038] Figure 1 The infrared spectrum of octadecylamine polyoxyethylene ether (AC1810);

[0039] Figure 2 The infrared spectrum of octadecylamine polyester ether (AEC1810) is shown. Detailed Implementation

[0040] Example 1

[0041] The fatty amine polyester ether surfactant of the present invention is a nonionic surfactant, and its structural formula is as follows:

[0042]

[0043] In the above structural formula:

[0044] m represents the degree of polymerization of the carbonate group in the fatty amine polyester ether surfactant molecule, and m is any integer from 1 to 10;

[0045] n represents the degree of polymerization of the ethoxy group in the fatty amine polyester ether surfactant molecule, and n is any integer from 1 to 10;

[0046] The sum of m+n is any integer from 2 to 20;

[0047] R represents the C12-18 alkyl group in the fatty amine polyester ether surfactant molecule.

[0048] Example 2

[0049] The fatty amine polyester ether surfactant of Example 1 can be prepared by the following method: 94.33 kg (350 mol) of octadecyl primary amine and 3.22 kg of potassium hydroxide catalyst are added to a reactor, and stirring is started until homogeneous. When the reactor temperature is raised to 80°C, 308 kg (3500 mol) of ethylene carbonate is added dropwise, and the reactor temperature is controlled between 80-100°C during the dropwise addition. After the dropwise addition is completed, the reactor temperature is raised to 145-150°C to carry out a ring-opening polymerization reaction for 8-10 hours. After the reaction is completed, the temperature is lowered to 20-30°C to obtain the octadecylamine polyester ether surfactant (AEC1810) of Example 2, with a molar ratio of octadecyl primary amine to ethylene carbonate of 1:10.

[0050] Example 3

[0051] The fatty amine polyester ether surfactant of Example 1 can be prepared by the following method: 94.33 kg (350 mol) of octadecyl primary amine and 5.68 kg of potassium hydroxide catalyst are added to a reactor, and stirring is started until homogeneous. When the reactor temperature is raised to 80°C, 616 kg (7000 mol) of ethylene carbonate is added dropwise, and the reactor temperature is controlled between 80-100°C during the dropwise addition. After the dropwise addition is completed, the reactor temperature is raised to 145-150°C for ring-opening polymerization for 8-10 hours. After the reaction is completed, the temperature is lowered to 20-30°C to obtain the octadecylamine polyester ether surfactant (AEC1820) of Example 3, with a molar ratio of octadecyl primary amine to ethylene carbonate of 1:20.

[0052] Example 4

[0053] The fatty amine polyester ether surfactant of Example 1 can be prepared by the following method: 94.33 kg (350 mol) of octadecyl primary amine and 8.15 kg of potassium hydroxide catalyst are added to a reactor, and stirring is started until homogeneous. When the reactor temperature is raised to 80°C, 924 kg (10500 mol) of ethylene carbonate is added dropwise, and the reactor temperature is controlled between 80-100°C during the dropwise addition. After the dropwise addition is completed, the reactor temperature is raised to 145-150°C to carry out a ring-opening polymerization reaction for 8-10 hours. After the reaction is completed, the temperature is lowered to 20-30°C to obtain the octadecylamine polyester ether surfactant (AEC1830) of Example 4, with a molar ratio of octadecyl primary amine to ethylene carbonate of 1:30.

[0054] Example 5

[0055] The preparation method of the composite ionic oil displacement agent of the present invention is as follows: 100 kg of ethylene glycol monobutyl ether (EDG), 550 kg of water, 150 kg of the octadecylamine polyester ether surfactant (AEC1810) prepared in Example 2, and 150 kg of naphthenic acid amide polyether ester sulfonate anionic surfactant are added sequentially to a stainless steel reactor. Stirring is started and the mixture is dissolved for 30 minutes. After the solution is homogenized, 50 kg of octadecyltrimethylammonium sulfate cationic surfactant is added to the reactor, and stirring is continued for another 30 minutes. After the solution is homogenized, the composite ionic oil displacement agent product of Example 5 is obtained.

[0056] Example 6

[0057] The preparation method of the composite ionic oil displacement agent of the present invention is as follows: 100 kg of ethylene glycol monobutyl ether (EDG), 550 kg of water, 150 kg of the octadecylamine polyester ether surfactant (AEC1820) prepared in Example 3, and 150 kg of naphthenic acid amide polyether ester sulfonate anionic surfactant are added sequentially to a stainless steel reactor. Stirring is started and the mixture is dissolved for 30 minutes. After the solution is homogenized, 50 kg of octadecyltrimethylammonium sulfate cationic surfactant is added to the reactor, and stirring is continued for another 30 minutes. After the solution is homogenized, the composite ionic oil displacement agent product of Example 6 is obtained.

[0058] Example 7

[0059] The preparation method of the composite ionic oil displacement agent of the present invention is as follows: 100 kg of ethylene glycol monobutyl ether (EDG), 550 kg of water, 150 kg of the octadecylamine polyester ether surfactant (AEC1830) prepared in Example 4, and 150 kg of naphthenic acid amide polyether ester sulfonate anionic surfactant are added sequentially to a stainless steel reactor. Stirring is started and the mixture is dissolved for 30 minutes. After the solution is homogenized, 50 kg of octadecyltrimethylammonium sulfate cationic surfactant is added to the reactor, and stirring is continued for another 30 minutes. After the solution is homogenized, the composite ionic oil displacement agent product of Example 7 is obtained.

[0060] Comparative Example 1

[0061] 450 kg of naphthenic acid amide polyether ester sulfonate anionic surfactant and 550 kg of water were added sequentially to a stainless steel reactor. The mixture was stirred and dissolved for 30 minutes. After the solution was homogenized, a naphthenic acid amide polyether ester sulfonate oil displacement agent, Comparative Example 1, was obtained.

[0062] The effects of the present invention will be further explained below:

[0063] 1. Infrared characterization (IR) of fatty amine polyester ethers

[0064] To further demonstrate the structural characteristics of the fatty amine polyester ether, octadecylamine polyoxyethylene ether (AC1810) and octadecylamine polyester ether (AEC1810) synthesized in Example 2 were taken as comparative samples, purified, and subjected to infrared spectroscopy analysis using KBr pellets. The test results are shown in the IR spectra. Figure 1 and IR Figure 2 As shown.

[0065] A comparison of the infrared spectra of octadecylamine polyoxyethylene ether (AC1810) and octadecylamine polyester ether (AEC1810) synthesized in Example 2 of this application shows that the infrared spectrum of octadecylamine polyester ether (AEC1810) is significantly different. Figure 2 In addition to the infrared spectrum (IR) of octadecylamine polyoxyethylene ether (AC1810), Figure 1 ) in "1100cm -1 The asymmetric stretching vibration absorption peak of the fatty ether COC at "" and "940cm -1 The absorption peaks of the symmetric stretching vibrations of the fatty ether COC and the "1250-1350 cm⁻¹" are observed. -1 The absorption peak of CN stretching vibration in aliphatic amines is observed at 1747 cm⁻¹. The infrared spectrum of octadecylamine polyester ether (AEC1810) shows an absorption peak at 1747 cm⁻¹. -1 At the location ", there is also a significant absorption peak of the C=O stretching vibration of carbonate, and at "1259 cm⁻¹". -1 The absorption peak of CO stretching vibration in the carbonate group with obvious absorption intensity further confirms the structural characteristics of polyester (2-hydroxyethyl carbonate) ether (2-hydroxyethyl ether) in octadecylamine polyester ether (AEC1810).

[0066] 2. Evaluation of interfacial tension in binary systems with different surfactant concentrations

[0067] Following the determination method in section 6.3 of Q / SY1583-2013, dehydrated crude oil from the South 7-1 Joint Station of the Ninth Operating Area of ​​Daqing Oilfield No. 2 Oil Production Plant, and 25 million molecular weight polyacrylamide for oil displacement from Daqing Refining & Chemical Company, binary system solutions with oil displacement agent concentrations of 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5%, and a polyacrylamide concentration of 1000 ppm were prepared using simulated brine from Examples 5, 6, 7, and Comparative Example 1, respectively. The interfacial tension between the oil displacement agent solutions of different concentrations and the crude oil was measured using a TX-500C rotating drop interfacial tensiometer at 45℃ and a rotation speed of 5000 rpm. The results are shown in the table below:

[0068]

[0069]

[0070] As can be seen from the data in the table above, the binary oil displacement system composed of composite ionic oil displacement agent and naphthenic acid amide polyether ester sulfonate oil displacement agent and polyacrylamide can maintain a concentration of <1×10⁻⁶ within a wide range of effective concentrations of 0.05% to 0.5%. - 2 The requirement for ultra-low interfacial tension is mN / m. However, the interfacial tension values ​​between the composite ionic oil displacement agent and crude oil at different concentrations are lower and more stable, indicating that the interfacial tension of the composite ionic oil displacement agent is superior to that of the naphthenic acid amide polyether ester sulfonate anionic oil displacement agent.

[0071] 3. Evaluation of viscosity and interfacial tension stability of binary systems

[0072] Following the determination method in section 6.9 of Q / SY1583-2013, under a polyacrylamide concentration of 1000 ppm, binary solutions with an oil displacement agent concentration of 0.2% were prepared for Examples 5, 6, 7, and Comparative Example 1. These solutions were placed in an oven at 45°C under anaerobic conditions and left for 0, 1, 3, 7, 15, 30, and 60 days, respectively. The viscosity of the binary solutions was measured, and the interfacial tension between the binary solutions and crude oil was also measured. The results are shown in the table below:

[0073]

[0074] As can be seen from the data in the table above, the interfacial tension of the binary oil displacement systems composed of composite ionic oil displacement agents, naphthenic acid amide polyether ester sulfonate oil displacement agents, and polyacrylamide remains <1×10⁻⁶ within 60 days. -2 Despite an ultra-low interfacial tension range (mN / m), viscosity retention remains at a high level. It fully meets the requirements of Q / SY1583-2013 standard, which specifies a viscosity retention rate of ≥90% and an interfacial tension of <1×10⁻⁶ within 30 days. -2 Ultra-low interfacial tension requirement of mN / m.

[0075] 4. Evaluation of the salt resistance of the binary system

[0076] Sodium chloride solutions with different salinities were prepared using distilled water. Under conditions of 1000 ppm polyacrylamide concentration, binary systems with an oil displacement agent concentration of 0.2% were prepared using water with different salinities for Examples 5, 6, 7, and Comparative Example 1. The interfacial tension between these solutions and crude oil was measured at 45°C and a rotation speed of 5000 rpm. The results are shown in the table below:

[0077]

[0078] As can be seen from the data in the table above, the interfacial tension of the binary oil displacement systems composed of composite ionic oil displacement agents, naphthenic acid amide polyether ester sulfonate oil displacement agents, and polyacrylamide remains <1×10⁻⁶ mg / L when the salinity is in the range of 1000–8000 mg / L. -2 With an ultra-low range of mN / m, it exhibits good salt resistance. However, the salt resistance of the composite ionic oil displacement agent is significantly better than that of the naphthenic acid amide polyether ester sulfonate anionic oil displacement agent. This is because the nonionic hydrophilic groups in the fatty amine polyester ether surfactant molecules of the composite ionic oil displacement agent are not easily deactivated by charge neutralization or changes in ion concentration in high-salt solutions, thus resulting in superior salt resistance.

[0079] 5. Hard water resistance test of binary system

[0080] Prepare Ca-containing solutions of different concentrations using distilled water. 2+ +Mg 2+ Simulated hard aqueous solution, polymer at 1000 ppm, using different concentrations of Ca-containing solutions. 2+ +Mg 2+ Solutions were prepared using binary systems with an oil displacement agent concentration of 0.2% according to Examples 5, 6, 7, and Comparative Example 1. The interfacial tension between these solutions and crude oil was measured at 45°C and a rotation speed of 5000 rpm. The results are shown in the table below:

[0081]

[0082] As can be seen from the data in the table above, the binary oil displacement systems composed of composite ionic oil displacement agents and naphthenic acid amide polyether ester sulfonate oil displacement agents, respectively, and polyacrylamide, in the Ca... 2+ +Mg 2+ Within the concentration range of 10–50 mg / L, the interfacial tension remains <1 × 10⁻⁶. -2 With an ultra-low range of mN / m, it exhibits good resistance to hard water. However, the hard water resistance of the composite ionic oil displacement agent is significantly better than that of the naphthenic acid amide polyether ester sulfonate anionic oil displacement agent.

[0083] 6. Multiple adsorption experiments of binary systems

[0084] Following the determination method in section 6.4 of Q / SY1583-2013, solutions of the oil displacement agent with a concentration of 0.2% were prepared for Examples 5, 6, 7, and Comparative Example 1. The solutions were then shaken at a solid-liquid ratio of 1:9 (oil sand to oil displacement agent solution) for 12 hours at 45°C and a shaking frequency of 90 times / min. The interfacial tension after oil sand adsorption was measured. The same experimental conditions were then repeated with the adsorbed oil displacement agent solution, and the interfacial tension values ​​were measured after four adsorption cycles. The results are shown in the table below.

[0085]

[0086] As can be seen from the data in the table above, the interfacial tension of the binary oil displacement system composed of naphthenic acid amide polyether ester sulfonate oil displacement agent and polyacrylamide in Comparative Example 1 was >1×10 after the fourth adsorption experiment. -2 The interfacial tension remained below 1×10⁻⁶ mN / m after four adsorption experiments, exhibiting an ultra-low range. Furthermore, the binary oil displacement system composed of the composite ionic oil displacement agent and polyacrylamide maintained an interfacial tension of <1×10⁻⁶ mN / m. -2 The results show an ultra-low range of mN / m. These experimental results further demonstrate that the anti-adsorption capacity of the composite ionic displacement agent is significantly improved compared to the naphthenic acid amide polyether ester sulfonate displacement agent.

[0087] 7. Binary system oil displacement experiment

[0088] The oil displacement effect of the binary system (S surfactant + P polymer) on artificial rock cores was tested according to the test method in Chapter 9 of the standard SY / T6424-2014 "Performance Test Method of Composite Oil Displacement System".

[0089] 7.1 Experimental Conditions

[0090] (1) Core: A homogeneous artificial physical core was used, with core dimensions of 4.0cm × 4.0cm × 30cm. The gas permeability and porosity of the core are shown in the table below:

[0091]

[0092] (2) Experimental water: The water used for both water flooding and binary systems was Daqing Oilfield standard simulated brine. The formula of the simulated brine is shown in the table below:

[0093] Ingredients Increase (m / m), % NaCl 0.1249 <![CDATA[NaHCO3]]> 0.2929 <![CDATA[Na2CO3]]> 0.0191 <![CDATA[Na2SO4]]> 0.0006 <![CDATA[CaCl2]]> 0.0033 <![CDATA[MgCl2·6H2O]]> 0.0059

[0094] (3) Chemical agents used in the experiment: The polymer used was 25 million molecular weight polyacrylamide for oil displacement from Daqing Petrochemical Company, and the oil displacement agent used was the product obtained in Examples 5, 6, 7 and Comparative Example 1 of this invention.

[0095] (4) Experimental oil: Dehydrated crude oil from the South 7-1 Joint Station of the Ninth Operating Area of ​​Daqing Oilfield No. 2 Oil Production Plant;

[0096] (5) Experimental temperature: All experiments were conducted at 45℃;

[0097] (6) Injection rate: 20 mL / h.

[0098] 7.2 Experimental Procedure

[0099] (1) After the core was evacuated for 4 hours, it was saturated with simulated brine and the porosity was measured.

[0100] (2) Place the core saturated with simulated brine in a constant temperature chamber for more than 4 hours (45℃);

[0101] (3) Saturate simulated crude oil and place the core in a constant temperature chamber for more than 12 hours (45℃). The crude oil saturation of the core should be as close as possible to the original oil saturation of the reservoir.

[0102] (4) Perform simulated oil displacement according to the procedure specified in SY / T6424-2014 "Performance Test Method for Composite Oil Displacement System" and calculate the recovery rate.

[0103] 7.3 Experimental Design

[0104] Option 1:

[0105] ① Simulate brine flooding to 98% water cut and calculate water flooding recovery rate;

[0106] ② Inject 0.3 pv of the binary system: polyacrylamide with a concentration of 1500 mg / L and a molecular weight of 25 million, and oil displacement agent with a concentration of 0.3% as described in Example 5;

[0107] ③Then, simulated brine is injected to drive the water content to 98%, and the total recovery rate is calculated.

[0108] Option 2:

[0109] ① Simulate brine flooding to 98% water cut and calculate water flooding recovery rate;

[0110] ② Inject 0.3 pv of the binary system: polyacrylamide with a concentration of 1500 mg / L and a molecular weight of 25 million, and oil displacement agent with a concentration of 0.3% as described in Example 6;

[0111] ③Then, simulated brine is injected to drive the water content to 98%, and the total recovery rate is calculated.

[0112] Option 3:

[0113] ① Simulate brine flooding to 98% water cut and calculate water flooding recovery rate;

[0114] ② Inject 0.3 pv of the binary system: polyacrylamide with a concentration of 1500 mg / L and a molecular weight of 25 million, and oil displacement agent with a concentration of 0.3% as described in Example 7;

[0115] ③Then, simulated brine is injected to drive the water content to 98%, and the total recovery rate is calculated.

[0116] Option 4:

[0117] ① Simulate brine flooding to 98% water cut and calculate water flooding recovery rate;

[0118] ② Inject 0.3 pv of the binary system: polyacrylamide with a concentration of 1500 mg / L and a molecular weight of 25 million, and oil displacement agent of Comparative Example 1 with a concentration of 0.3%;

[0119] ③Then, simulated brine is injected to drive the water content to 98%, and the total recovery rate is calculated.

[0120] 7.4 Oil displacement experiment results data

[0121]

[0122] As shown in the table above, the naphthenic acid amide polyether sulfonate oil displacement agent in Comparative Example 1, in a binary system oil displacement experiment using artificial cores, can achieve an oil recovery rate increase of over 20% after waterflooding. The composite ionic oil displacement agents in Examples 5, 6, and 7, on average, increase the oil recovery rate after waterflooding by over 28.20%. The composite ionic oil displacement agent increases the oil recovery rate more significantly than the naphthenic acid amide polyether sulfonate anionic oil displacement agent.

[0123] The experimental data above show that the composite ionic oil displacement agent outperforms the single naphthenic acid amide polyether sulfonate anionic oil displacement agent in terms of overall performance, interfacial tension stability, salt resistance, hard water resistance, anti-adsorption performance, and binary system oil displacement performance. Specifically, the octadecyltrimethylammonium sulfate cationic surfactant and octadecylamine polyester ether surfactant in the composite ionic oil displacement agent do not react with Ca... 2+ Mg 2+ Ions undergo charge bonding or precipitation reactions, thus significantly enhancing hard water resistance. In particular, octadecylamine polyester ether surfactants are nonionic, containing no ionic groups in their molecules. The solubility and performance of their nonionic hydrophilic groups are less affected by salt concentration, resulting in superior salt resistance.

Claims

1. A fatty amine polyester ether surfactant, characterized in that... This surfactant is a nonionic surfactant, and its structural formula is as follows: In the above structural formula: m represents the degree of polymerization of the carbonate group in the fatty amine polyester ether surfactant molecule, and m is any integer from 1 to 10; n represents the degree of polymerization of the ethoxy group in the fatty amine polyester ether surfactant molecule, and n is any integer from 1 to 10; The sum of m+n is any integer from 2 to 20; R represents the C12-18 alkyl group in the fatty amine polyester ether surfactant molecule.

2. A method for preparing the fatty amine polyester ether surfactant according to claim 1, characterized in that: This is achieved through the following steps: A fatty amine polyester ether surfactant was prepared by ring-opening polymerization of fatty amines with ethylene carbonate under certain temperature and the action of potassium hydroxide catalyst. The fatty amine is a C12-18 alkyl primary amine; The amount of potassium hydroxide catalyst added is 5-10 wt.‰ of the total weight of the fatty amine and ethylene carbonate; The molar ratio of the fatty amine to ethylene carbonate is 1:4 to 40.

3. The method for preparing fatty amine polyester ether surfactants according to claim 2, characterized in that... The fatty amine is an alkyl C18 octadecyl primary amine.

4. The method for preparing fatty amine polyester ether surfactants according to claim 2, characterized in that... The amount of potassium hydroxide catalyst added is 8 wt.‰ of the total weight of the fatty amine and ethylene carbonate.

5. A composite ionic oil displacement agent prepared using the fatty amine polyester ether surfactant according to claim 1, characterized in that... It is prepared from the following components by weight percentage: The fatty amine polyester ether surfactant has a weight percentage of 10–20 wt.%. The weight percentage of the naphthenic acid amide polyether ester sulfonate anionic surfactant is 10-20 wt.%. The alkyltrimethylammonium sulfate cationic surfactant has a weight percentage of 1–10 wt.%. The solvent weight percentage is 10-15 wt.%. The remainder is water.

6. The method for preparing a composite ionic oil displacement agent using the fatty amine polyester ether surfactant as described in claim 5, characterized in that... The fatty amine polyester ether surfactant has a weight percentage of 15 wt.%; the naphthenic acid amide polyether ester sulfonate anionic surfactant has a weight percentage of 15 wt.%.

7. The composite ionic oil displacement agent as described in claim 5, characterized in that... The alkyltrimethylammonium sulfate cationic surfactant described above has the following structural formula: RN(CH3)3OSO3CH3 In the above structural formula: R represents the C12-18 alkyl group in the alkyltrimethylammonium sulfate molecule.

8. The method for preparing a composite ionic oil displacement agent using the fatty amine polyester ether surfactant as described in claim 5, characterized in that... The alkyltrimethylammonium sulfate is octadecyltrimethylammonium sulfate with an alkyl C18 structure, and its weight percentage is 5 wt.%.

9. The method for preparing a composite ionic oil displacement agent using the fatty amine polyester ether surfactant as described in claim 5, characterized in that... The solvent is ethylene glycol monobutyl ether, 10 wt.%.

10. A method for preparing the composite ionic displacement agent according to claim 5, characterized in that: The process is achieved through the following steps: Ethylene glycol monobutyl ether, water, fatty amine polyester ether surfactant, and naphthenic acid amide polyether ester sulfonate anionic surfactant are added sequentially to a stainless steel reactor according to the formula ratio by weight. Stirring is initiated and the mixture is dissolved for 30 minutes. After the solution is homogenized, alkyl trimethyl methyl sulfate ammonium cationic surfactant is added to the reactor, and stirring is continued for another 30 minutes. Once the solution is homogenized, the composite ionic oil displacement agent product is obtained.

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