Surfactant for improving recovery efficiency of oil field and preparation method of surfactant

Abstract

The invention discloses a surfactant for improving the recovery efficiency of an oil field, and relates to the technical field of oil field recovery. The cleaning agent is prepared from the following materials in parts: 10 to 500 parts of mahogany petroleum sulfonate, 20 to 450 parts of alkylbenzene sulfonate, 10 to 590 parts of fatty alcohol, 1 to 50 parts of ethylene oxide, 1 to 90 parts of silicon dioxide nanoparticles, 2 to 79 parts of alkyl halide, 20 to 90 parts of sodium hydroxide, 1 to 80 parts of sodium carbonate, 5 to 50 parts of xanthan gum, 1 to 78 parts of carbon nanotubes and 100 to 1000 parts of water. The invention further discloses a preparation method of the surfactant for improving the recovery efficiency of the oil field. Through the introduced material, the oil-water interfacial tension can be effectively reduced, crude oil can be more easily stripped from the rock surface, the oil displacement efficiency is remarkably improved, the oil displacement agent can be flexibly adjusted according to different oil reservoir conditions to adapt to a complex stratum environment, the oil displacement agent has good emulsifying performance, the crude oil can form a stable emulsion in water, and the fluidity of the crude oil is improved; the nanoparticles can form a stable interfacial film on an oil-water interface.

Description

Technical Field

[0001] The invention relates to the technical field of oil field recovery, in particular to a surfactant used for improving oil field recovery rate and a preparation method thereof. Background Art

[0002] In the field of oil extraction, with the advancement of the extraction process, most conventional oil fields have entered the middle and late stages of extraction, and the difficulty of crude oil extraction is increasing. Improving oil recovery has become a key issue that the industry needs to solve urgently. At present, injecting surfactants to reduce oil-water interfacial tension and improve crude oil fluidity is one of the important means to improve oil recovery. However, existing surfactants for oil fields have many limitations. Traditional surfactants have poor stability in complex reservoir environments, such as high temperature, high salt, and high calcium and magnesium ion concentration formations. They are prone to degradation or precipitation, resulting in a significant decrease in their performance and are unable to effectively reduce interfacial tension and drive oil. In addition, some surfactants have poor compatibility with crude oil and cannot fully disperse crude oil, making it difficult for oil recovery efficiency to reach an ideal level, which leads to a significant reduction in oil field recovery. In this regard, we propose a surfactant for improving oil field recovery and a preparation method thereof. Summary of the invention

[0003] In order to solve the above technical problems, a surfactant for improving oil field recovery and a preparation method thereof are provided. This technical solution solves the above-mentioned problem of reduced oil field recovery.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: a surfactant for improving oil field recovery, which is prepared from the following materials: 10-500 parts of petroleum sulfonate, 20-450 parts of alkylbenzene sulfonate, 10-590 parts of fatty alcohol, 1-50 parts of ethylene oxide, 1-90 parts of silicon dioxide nanoparticles, 2-79 parts of halogenated alkane, 20-90 parts of sodium hydroxide, 1-80 parts of sodium carbonate, 5-50 parts of xanthan gum, 1-78 parts of carbon nanotubes and 100-1000 parts of water.

[0005] Preferably, it is prepared from the following materials: 500 parts of petroleum sulfonate, 450 parts of alkylbenzene sulfonate, 500 parts of fatty alcohol, 45 parts of ethylene oxide, 55 parts of silica nanoparticles, 65 parts of halogenated alkane, 20 parts of sodium hydroxide, 78 parts of sodium carbonate, 15 parts of xanthan gum, 22 parts of carbon nanotubes and 800 parts of water.

[0006] Preferably, the petroleum sulfonate is one of monosulfonic acid and disulfonic acid, the petroleum sulfonic acid is prepared by sulfonation reaction, sulfonation is carried out with fuming sulfuric acid, sulfur trioxide and petroleum fraction to generate petroleum sulfonate, and the petroleum sulfonate is obtained by separation and purification; the alkylbenzene sulfonate is one of linear alkylbenzene sulfonate and branched alkylbenzene sulfonate, and the sodium carbonate includes anhydrous sodium carbonate, sodium carbonate monohydrate and sodium carbonate decahydrate.

[0007] Preferably, the fatty alcohol is one of a saturated fatty alcohol and an unsaturated fatty alcohol, and the preparation of the fatty alcohol is based on a natural oil hydrogenation method, using natural oil as a raw material, reacting with hydrogen under the action of a catalyst to convert the fatty acid glyceride in the oil into fatty alcohol; the ethylene oxide is one of industrial grade ethylene oxide and high-purity ethylene oxide, and the silica nanoparticles include spherical silica nanoparticles and non-spherical silica nanoparticles, which are prepared based on a gas phase reaction; the alkyl halide is one or more of a fluoroalkane, a chloroalkane, a bromide and an iodide.

[0008] Preferably, the xanthan gum is one of low-viscosity xanthan gum, medium-viscosity xanthan gum and high-viscosity xanthan gum; the carbon nanotubes are one of single-walled carbon nanotubes and multi-walled carbon nanotubes; the sodium hydroxide is one of flake sodium hydroxide, granular sodium hydroxide and liquid sodium hydroxide; and the water is deionized water.

[0009] A method for preparing a surfactant for improving oil field recovery, the preparation steps are:

[0010] S1. Prepare materials, including: 10-500 parts of petroleum sulfonate, 20-450 parts of alkylbenzene sulfonate, 10-590 parts of fatty alcohol, 1-50 parts of ethylene oxide, 1-90 parts of silicon dioxide nanoparticles, 2-79 parts of alkyl halide, 20-90 parts of sodium hydroxide, 1-80 parts of sodium carbonate, 5-50 parts of xanthan gum, 1-78 parts of carbon nanotubes and 100-1000 parts of water;

[0011] S2, sodium hydroxide and sodium carbonate solution preparation, add sodium hydroxide and water in a reactor and stir, dissolve, make sodium hydroxide solution, take out for use; add sodium carbonate and water in a reactor and stir, get sodium carbonate solution, take out for use;

[0012] S3, reacting fatty alcohol with ethylene oxide, adding fatty alcohol into a reactor, stirring and heating to 120-150°C, slowly adding ethylene oxide into the reactor through a constant pressure dropping funnel, the dropping time is 2h;

[0013] Wait for the addition to be completed, and continue stirring the reaction for 3-4 hours to allow the fatty alcohol to react with ethylene oxide to obtain fatty alcohol polyoxyethylene ether;

[0014] S4, mixing surfactant materials, cooling the prepared fatty alcohol polyoxyethylene ether to 60-80°C, adding petroleum sulfonate and alkylbenzene sulfonate, stirring for 1-2h, and mixing evenly; then adding silica nanoparticles, and increasing the stirring speed to 500-600r / min, stirring for 2-3h, and dispersing the silica nanoparticles in the system; continuing to add alkyl halides, xanthan gum and carbon nanotubes and stirring for 3-4h, stirring and dispersing evenly;

[0015] S5, neutralization pH adjustment, under stirring, sodium hydroxide solution and sodium carbonate solution are added dropwise to the reaction kettle to adjust the pH value of the system to 7-9;

[0016] S6, filtration and finished product, take out the mixture and filter it through a filter to remove impurities and agglomerates, transfer the filtered product to a storage container to obtain a surfactant.

[0017] Preferably, the specific operation steps in step S2 are as follows: sodium hydroxide and water are added to a reactor in a predetermined ratio, stirring is started, the stirring speed is set to 200-300 r / min, stirring is continued for 20 minutes, until the sodium hydroxide is completely dissolved to form a sodium hydroxide solution, and the solution is transferred to a storage container and labeled for standby use; similarly, sodium carbonate powder and water are added to the reactor, stirred and dissolved to obtain a sodium carbonate solution.

[0018] Preferably, in step S3, fatty alcohol is added to the reactor to mix the fatty alcohol in the reactor, the reactor is heated, and during the reaction, changes in temperature and pressure in the reactor are monitored, and real-time monitoring is performed based on temperature sensors and pressure sensors. During the reaction, the reactor is ensured to be completely sealed.

[0019] Preferably, the cooling time in step S4 is 2 hours, and the cooling rate is slow. After adding petroleum sulfonic acid to the reactor and stirring for 30 minutes, alkylbenzene sulfonate is added to the reactor again and stirred continuously. After stirring evenly, the silica nanoparticles are added.

[0020] Preferably, in step S6, the pore size of the filter screen on the filter is 10-50 μm, and the filtered product is tested and packaged.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The material introduced in the present invention can effectively reduce the oil-water interfacial tension, make crude oil easier to peel off from the rock surface, and significantly improve the oil recovery efficiency. It can be flexibly adjusted according to different reservoir conditions to adapt to complex formation environments. It has good emulsification properties and can form a stable emulsion of crude oil in water, thereby increasing the fluidity of crude oil. Nanoparticles can form a stable interfacial film at the oil-water interface to prevent droplet aggregation, react with acidic substances in crude oil, reduce the viscosity of crude oil, and improve the fluidity of crude oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of the steps for preparing the surfactant. DETAILED DESCRIPTION

[0024] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0025] Reference Figure 1 As shown, a surfactant for improving oil field recovery is prepared from the following materials: 10-500 parts of petroleum sulfonate, 20-450 parts of alkylbenzene sulfonate, 10-590 parts of fatty alcohol, 1-50 parts of ethylene oxide, 1-90 parts of silicon dioxide nanoparticles, 2-79 parts of halogenated alkane, 20-90 parts of sodium hydroxide, 1-80 parts of sodium carbonate, 5-50 parts of xanthan gum, 1-78 parts of carbon nanotubes and 100-1000 parts of water.

[0026] It is specifically prepared from the following materials: 500 parts of petroleum sulfonate, 450 parts of alkylbenzene sulfonate, 500 parts of fatty alcohol, 45 parts of ethylene oxide, 55 parts of silica nanoparticles, 65 parts of halogenated alkane, 20 parts of sodium hydroxide, 78 parts of sodium carbonate, 15 parts of xanthan gum, 22 parts of carbon nanotubes and 800 parts of water.

[0027] Petroleum sulfonates and alkylbenzene sulfonates have excellent surface activity and can effectively reduce the oil-water interfacial tension, making it easier for crude oil to be stripped from the rock surface, significantly improving oil recovery efficiency. Petroleum sulfonates and alkylbenzene sulfonates can be flexibly adjusted according to different reservoir conditions to adapt to complex formation environments;

[0028] The fatty alcohol polyoxyethylene ether produced by the reaction of fatty alcohol and ethylene oxide has good emulsifying properties, which can form a stable emulsion of crude oil in water, increase the fluidity of crude oil, and help improve the recovery rate. At the same time, this substance can improve the solubility and salt resistance of the surfactant system;

[0029] Adding silica nanoparticles can enhance the viscosity and stability of the surfactant solution. Nanoparticles can form a stable interfacial film at the oil-water interface, preventing droplet aggregation, further reducing interfacial tension and improving oil displacement effects.

[0030] The addition of halogenated alkanes helps to adjust the molecular structure and properties of surfactants, enhance their interaction with crude oil, and improve the solubility of surfactants in the oil phase, thereby improving the emulsification and dispersion capabilities of crude oil.

[0031] Sodium hydroxide and sodium carbonate can adjust the pH value of the system and maintain the chemical stability of the system. They can also react with the acidic substances in crude oil to reduce the viscosity of crude oil, improve the fluidity of crude oil, and facilitate oil recovery;

[0032] Xanthan gum has good thickening properties, which can increase the viscosity of the solution and improve the sweep efficiency of the oil displacement agent. Carbon nanotubes can further enhance the mechanical properties and stability of the system. The two work synergistically to improve the adaptability of surfactants in complex reservoir environments.

[0033] Petroleum sulfonate is one of monosulfonic acid and disulfonic acid, and the petroleum sulfonic acid is prepared by sulfonation reaction, which is sulfonated by fuming sulfuric acid, sulfur trioxide and petroleum fraction to generate petroleum sulfonate, which is obtained by separation and purification; alkylbenzene sulfonate is one of linear alkylbenzene sulfonate and branched alkylbenzene sulfonate, and sodium carbonate includes anhydrous sodium carbonate, sodium carbonate monohydrate and sodium carbonate decahydrate.

[0034] The fatty alcohol is one of a saturated fatty alcohol and an unsaturated fatty alcohol. The preparation of the fatty alcohol is based on a natural oil hydrogenation method, which uses natural oil as a raw material and reacts with hydrogen under the action of a catalyst to convert the fatty acid glyceride in the oil into a fatty alcohol; the ethylene oxide is one of an industrial grade ethylene oxide and a high-purity ethylene oxide; the silica nanoparticles include spherical silica nanoparticles and non-spherical silica nanoparticles, which are prepared based on a gas phase reaction; the alkyl halide is one or more of a fluoroalkane, a chloroalkane, a bromoalkane and an iodoalkane.

[0035] The xanthan gum is one of low-viscosity xanthan gum, medium-viscosity xanthan gum and high-viscosity xanthan gum; the carbon nanotube is one of single-walled carbon nanotube and multi-walled carbon nanotube; the sodium hydroxide is one of flake sodium hydroxide, granular sodium hydroxide and liquid sodium hydroxide; and the water is deionized water.

[0036] A method for preparing a surfactant for improving oil field recovery, the preparation steps are:

[0037] S1. Prepare materials, including: 10-500 parts of petroleum sulfonate, 20-450 parts of alkylbenzene sulfonate, 10-590 parts of fatty alcohol, 1-50 parts of ethylene oxide, 1-90 parts of silicon dioxide nanoparticles, 2-79 parts of alkyl halide, 20-90 parts of sodium hydroxide, 1-80 parts of sodium carbonate, 5-50 parts of xanthan gum, 1-78 parts of carbon nanotubes and 100-1000 parts of water;

[0038] S2, sodium hydroxide and sodium carbonate solution preparation, add sodium hydroxide and water in a reactor and stir, dissolve, make sodium hydroxide solution, take out for use; add sodium carbonate and water in a reactor and stir, get sodium carbonate solution, take out for use;

[0039] S3, reacting fatty alcohol with ethylene oxide, adding fatty alcohol into a reactor, stirring and heating to 120-150°C, slowly adding ethylene oxide into the reactor through a constant pressure dropping funnel, the dropping time is 2h;

[0040] Wait for the addition to be completed, and continue stirring the reaction for 3-4 hours to allow the fatty alcohol to react with ethylene oxide to obtain fatty alcohol polyoxyethylene ether;

[0041] S4, mixing surfactant materials, cooling the prepared fatty alcohol polyoxyethylene ether to 60-80°C, adding petroleum sulfonate and alkylbenzene sulfonate, stirring for 1-2h, and mixing evenly; then adding silica nanoparticles, and increasing the stirring speed to 500-600r / min, stirring for 2-3h, and dispersing the silica nanoparticles in the system; continuing to add alkyl halides, xanthan gum and carbon nanotubes and stirring for 3-4h, stirring and dispersing evenly;

[0042] S5, neutralization pH adjustment, under stirring, sodium hydroxide solution and sodium carbonate solution are added dropwise to the reaction kettle to adjust the pH value of the system to 7-9;

[0043] S6, filtration and finished product, take out the mixture and filter it through a filter to remove impurities and agglomerates, transfer the filtered product to a storage container to obtain a surfactant.

[0044] The specific operation steps in step S2 are as follows: sodium hydroxide and water are added to the reactor in a predetermined ratio, stirring is started, the stirring speed is set to 200-300 r / min, and stirring is continued for 20 minutes until the sodium hydroxide is completely dissolved to form a sodium hydroxide solution, and the solution is transferred to a storage container and labeled for standby use; similarly, sodium carbonate powder and water are added to the reactor, stirred and dissolved, and a sodium carbonate solution is obtained.

[0045] The present application sets the stirring speed at 200-300r / min, which can ensure that the liquid in the reactor is fully mixed while avoiding excessive foaming or splashing of the solution due to too fast a speed. This speed range can effectively promote the full contact between sodium hydroxide and water, sodium carbonate powder and water, accelerate the dissolution rate, and make the dissolution process more efficient. Compared with low-speed stirring, it can greatly shorten the dissolution time and improve the overall production efficiency; and compared with high-speed stirring, it reduces unnecessary energy consumption and equipment loss;

[0046] Continuous stirring for 20 minutes provides sufficient time for the complete dissolution of sodium hydroxide and sodium carbonate, ensuring that the two substances are fully dissolved, so that the concentrations of the final sodium hydroxide solution and sodium carbonate solution are uniform, avoiding the influence of local uneven concentration on subsequent reactions. The uniformity of solution concentration is crucial to ensure the stability of the quality of the final surfactant product, and can effectively avoid the fluctuation of surfactant performance caused by solution quality problems;

[0047] Transfer the dissolved solution to a storage container and label it for later use. On the one hand, this can prevent the solution from being contaminated by the outside world and ensure the purity of the solution, thereby ensuring that no impurities are introduced during subsequent reactions that affect the reaction effect. On the other hand, clear labeling makes it easy for operators to quickly identify the type of solution and related information, avoiding confusion when taking the solution, improving the accuracy of the operation and work efficiency, and ensuring that the entire production process proceeds in an orderly manner.

[0048] In step S3, fatty alcohol is added into the reactor to mix the fatty alcohol in the reactor, and the reactor is heated. During the reaction, the temperature and pressure changes in the reactor are monitored, and real-time monitoring is performed based on temperature sensors and pressure sensors. During the reaction, the reactor is ensured to be completely sealed.

[0049] The present application adds fatty alcohol to the reactor and mixes it thoroughly, which can ensure that the fatty alcohol is evenly distributed in the reaction system. The advantage of this is that when it comes into contact with other reactants later, each molecule of the fatty alcohol has an equal opportunity to participate in the reaction, which is conducive to the consistency and completeness of the reaction. If the fatty alcohol is unevenly distributed, it may cause local overreaction or underreaction, affecting the quality and performance of the product, such as causing differences in the emulsification and dispersion properties of the surfactant in different batches or different parts of the same batch; during the reaction process, as the temperature rises and the reaction proceeds, the pressure in the reactor may change, and excessive pressure may cause a serious safety accident of explosion. By monitoring the pressure in real time through a pressure sensor, abnormal pressure can be discovered in time, and corresponding decompression measures can be taken, such as adjusting the exhaust valve, to ensure that the reactor operates within a safe pressure range, to ensure the life safety of the operator and the integrity of the production equipment.

[0050] In step S4, the cooling time is 2 hours, and the cooling rate is slow. After adding petroleum sulfonic acid into the reactor and stirring for 30 minutes, alkylbenzene sulfonate is added into the reactor again and stirred continuously. After stirring evenly, silica nanoparticles are added. In step S6, the pore size of the filter on the filter is 10-50 μm, and the filtered product is tested and packaged.

[0051] In this application, the cooling time of the reaction product is set to 2h and the cooling rate is slow. This can avoid changes in product properties caused by too fast cooling. Rapid cooling may cause drastic changes in the molecular structure of the system, or destroy the already formed microstructure, thereby affecting the stability and performance of the product. Slow cooling can allow the various components in the system to have enough time to adapt to temperature changes, thereby making the interactions between them more stable and ensuring the quality of the final product.

[0052] Surfactant Recovery Oilfield Efficiency Experimental Procedure

[0053] Experimental preparation:

[0054] Prepare samples of surfactant solutions for formulation and samples of existing surfactants;

[0055] Prepare multiple simulated reservoir core models to ensure that their permeability and porosity parameters are similar, and that they have been cleaned, dried, and basic parameters have been measured;

[0056] Prepare sufficient simulated crude oil, whose composition is similar to that of the target reservoir crude oil, and prepare high-precision metering pumps, pressure sensors, and intermediate container equipment required for displacement experiments;

[0057] Saturated crude oil: inject simulated crude oil into the core model at a constant low speed through a metering pump until no liquid flows out of the core outlet. Record the volume of crude oil injected at this time and calculate the oil saturation of the core.

[0058] Water flooding experiment: Inject water into the core model saturated with crude oil at a constant flow rate until the water content of the produced fluid at the outlet reaches more than 98%, record the amount of crude oil produced by water flooding, and calculate the water flooding recovery factor;

[0059] Surfactant flooding experiment: Surfactant solutions of different formulations were injected into the core model at the same flow rate as water flooding, and the flooding was continued until the water content of the produced fluid at the outlet was stabilized above 98% again. The amount of crude oil produced this time was recorded, and the recovery factor increased by surfactant flooding was calculated. At the same time, during the flooding process, the pressure sensor was used to monitor the pressure changes at both ends of the core in real time.

[0060] Comparative experiment: A blank control group was set up, that is, only water flooding experiment was carried out without injecting surfactant solution, so as to compare and evaluate the effect of surfactant on improving recovery rate.

[0061] Table 1 below is the data table obtained during the experiment

[0062]

[0063] Table 1

[0064] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A surfactant for enhancing oil recovery in oil fields, characterized in that: The invention is prepared from the following materials: 10-500 parts of petroleum sulfonate, 20-450 parts of alkylbenzene sulfonate, 10-590 parts of fatty alcohol, 1-50 parts of ethylene oxide, 1-90 parts of silicon dioxide nanoparticles, 2-79 parts of alkyl halides, 20-90 parts of sodium hydroxide, 1-80 parts of sodium carbonate, 5-50 parts of xanthan gum, 1-78 parts of carbon nanotubes and 100-1000 parts of water.

2. A surfactant for enhancing oil field recovery according to claim 1, characterized in that: It is specifically prepared from the following materials: 500 parts of petroleum sulfonate, 450 parts of alkylbenzene sulfonate, 500 parts of fatty alcohol, 45 parts of ethylene oxide, 55 parts of silica nanoparticles, 65 parts of halogenated alkane, 20 parts of sodium hydroxide, 78 parts of sodium carbonate, 15 parts of xanthan gum, 22 parts of carbon nanotubes and 800 parts of water.

3. The surfactant for enhancing oil field recovery according to claim 1, characterized in that: Petroleum sulfonate is one of monosulfonic acid and disulfonic acid, and the petroleum sulfonic acid is prepared by sulfonation reaction, which is sulfonated by fuming sulfuric acid, sulfur trioxide and petroleum fraction to generate petroleum sulfonate, which is obtained by separation and purification; alkylbenzene sulfonate is one of linear alkylbenzene sulfonate and branched alkylbenzene sulfonate, and sodium carbonate includes anhydrous sodium carbonate, sodium carbonate monohydrate and sodium carbonate decahydrate.

4. The surfactant for enhancing oil field recovery according to claim 1, characterized in that: The fatty alcohol is one of a saturated fatty alcohol and an unsaturated fatty alcohol. The preparation of the fatty alcohol is based on a natural oil hydrogenation method, which uses natural oil as a raw material and reacts with hydrogen under the action of a catalyst to convert the fatty acid glyceride in the oil into a fatty alcohol; the ethylene oxide is one of an industrial grade ethylene oxide and a high-purity ethylene oxide; the silica nanoparticles include spherical silica nanoparticles and non-spherical silica nanoparticles, which are prepared based on a gas phase reaction; the alkyl halide is one or more of a fluoroalkane, a chloroalkane, a bromoalkane and an iodoalkane.

5. The surfactant for enhancing oil field recovery according to claim 1, characterized in that: The xanthan gum is one of low-viscosity xanthan gum, medium-viscosity xanthan gum and high-viscosity xanthan gum; the carbon nanotube is one of single-walled carbon nanotube and multi-walled carbon nanotube; the sodium hydroxide is one of flake sodium hydroxide, granular sodium hydroxide and liquid sodium hydroxide; and the water is deionized water.

6. A method for preparing a surfactant for enhancing oil field recovery, characterized in that: The preparation steps are: S1. Prepare materials, including: 10-500 parts of petroleum sulfonate, 20-450 parts of alkylbenzene sulfonate, 10-590 parts of fatty alcohol, 1-50 parts of ethylene oxide, 1-90 parts of silicon dioxide nanoparticles, 2-79 parts of alkyl halide, 20-90 parts of sodium hydroxide, 1-80 parts of sodium carbonate, 5-50 parts of xanthan gum, 1-78 parts of carbon nanotubes and 100-1000 parts of water; S2, sodium hydroxide and sodium carbonate solution preparation, add sodium hydroxide and water in a reactor and stir, dissolve, make sodium hydroxide solution, take out for use; add sodium carbonate and water in a reactor and stir, get sodium carbonate solution, take out for use; S3, reacting fatty alcohol with ethylene oxide, adding fatty alcohol into a reactor, stirring and heating to 120-150°C, slowly adding ethylene oxide into the reactor through a constant pressure dropping funnel, the dropping time is 2h; Wait for the addition to be completed, and continue stirring the reaction for 3-4 hours to allow the fatty alcohol to react with ethylene oxide to obtain fatty alcohol polyoxyethylene ether; S4, mixing surfactant materials, cooling the prepared fatty alcohol polyoxyethylene ether to 60-80°C, adding petroleum sulfonate and alkylbenzene sulfonate, stirring for 1-2h, and mixing evenly; then adding silica nanoparticles, and increasing the stirring speed to 500-600r / min, stirring for 2-3h, and dispersing the silica nanoparticles in the system; continuing to add alkyl halides, xanthan gum and carbon nanotubes and stirring for 3-4h, stirring and dispersing evenly; S5, neutralization pH adjustment, under stirring, sodium hydroxide solution and sodium carbonate solution are added dropwise to the reaction kettle to adjust the pH value of the system to 7-9; S6, filtration and finished product, take out the mixture and filter it through a filter to remove impurities and agglomerates, transfer the filtered product to a storage container to obtain a surfactant.

7. The method for preparing a surfactant for enhancing oil field recovery according to claim 6, characterized in that: The specific operation steps in step S2 are as follows: sodium hydroxide and water are added to the reactor in a predetermined ratio, stirring is started, the stirring speed is set to 200-300 r / min, and stirring is continued for 20 minutes until the sodium hydroxide is completely dissolved to form a sodium hydroxide solution, and the solution is transferred to a storage container and labeled for standby use; similarly, sodium carbonate powder and water are added to the reactor, stirred and dissolved, and a sodium carbonate solution is obtained.

8. The method for preparing a surfactant for enhancing oil field recovery according to claim 6, characterized in that: In step S3, fatty alcohol is added into the reactor to mix the fatty alcohol in the reactor, and the reactor is heated. During the reaction, the temperature and pressure changes in the reactor are monitored, and real-time monitoring is performed based on temperature sensors and pressure sensors. During the reaction, the reactor is ensured to be completely sealed.

9. The method for preparing a surfactant for enhancing oil field recovery according to claim 6, characterized in that: In step S4, the cooling time is 2 hours, and the cooling rate is slow. After adding petroleum sulfonic acid into the reactor and stirring for 30 minutes, alkylbenzene sulfonate is added into the reactor again, and stirring is continued. After stirring evenly, silica nanoparticles are added.

10. The method for preparing a surfactant for enhancing oil field recovery according to claim 6, characterized in that: In step S6, the pore size of the filter screen is 10-50 μm, and the filtered product is tested and packaged.

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