Microemulsion type thick oil viscosity reducer as well as preparation method and application thereof

Abstract

The invention relates to the technical field of micro-emulsion type thick oil viscosity reducers, in particular to a micro-emulsion type thick oil viscosity reducer and a preparation method and application thereof.The micro-emulsion type thick oil viscosity reducer is composed of a surfactant, a cosurfactant, an oil phase and a water phase, the surfactant is formed by compounding polyoxyethylene fatty alcohol ether gemini and potassium perfluorooctane sulfonate according to the ratio of 3: 1, the cosurfactant is n-butyl alcohol, and the oil phase is water. The surfactant is a cosurfactant, the oil phase is aviation kerosene, the water phase is deionized water containing 0.5%-1.5% of sodium chloride, the mass percentages of the components are as follows: 5%-10% of the surfactant, 3%-8% of the cosurfactant, 15%-25% of the oil phase and 60%-77% of the water phase, and the ratio is optimized, so that the components can synergistically form a stable and efficient microemulsion structure for reducing the viscosity of the heavy oil. The viscosity reducing agent has a remarkable viscosity reducing effect, can reduce the viscosity by more than 90% when being mixed with thickened oil in proportion, can improve the recovery efficiency, reduce the conveying energy consumption and reduce the pipeline blockage, and is simple to prepare, wide in raw material range, low in cost, good in stability, strong in adaptability and good in benefit.

Description

Technical Field

[0001] The present invention relates to the technical field of microemulsion type heavy oil viscosity reducers, and specifically relates to a microemulsion type heavy oil viscosity reducer, a preparation method thereof, and an application thereof. Background Art

[0002] As an important petroleum resource, heavy oil accounts for a relatively large proportion in the global petroleum reserves. However, due to its high viscosity and high density characteristics, heavy oil brings huge challenges to exploitation and transportation. During the heavy oil exploitation process, the high viscosity makes the heavy oil have extremely poor fluidity and is difficult to flow out smoothly from the oil layer, resulting in low recovery rate. Traditional exploitation methods, such as primary oil recovery relying on natural energy drive, have little effect on heavy oil, and the recovery rate is often lower than 10%. Secondary oil recovery replenishes formation energy by injecting water, but has limited viscosity reduction effect on heavy oil and cannot significantly improve the recovery rate.

[0003] In terms of transportation, the high viscosity of heavy oil will cause a substantial increase in transportation resistance, require a large amount of energy to maintain transportation, and increase the transportation cost. At the same time, the high viscosity is also prone to cause pipeline blockage, affecting the safety and stability of transportation. To solve the viscosity problem in the exploitation and transportation of heavy oil, various viscosity reduction methods have been developed.

[0004] Viscosity reduction by heating is one of the more common methods. By injecting steam into the oil layer or setting heating equipment in the transportation pipeline, the temperature of heavy oil is increased to reduce its viscosity. However, this method has high energy consumption and is difficult to maintain the temperature during long-distance transportation, and the viscosity reduction effect is limited. Viscosity reduction by blending with light oil is to mix low-viscosity light oil with heavy oil to reduce the viscosity of the mixture. However, light oil resources are relatively limited and the cost is high, and the properties of the blended oil may not meet the requirements of subsequent processing.

[0005] The chemical viscosity reduction method uses viscosity reducers to reduce the viscosity of heavy oil, and has the advantages of low cost and good effect, becoming a current research hotspot. Existing chemical viscosity reducers mainly include surfactant type, polymer type, etc. However, traditional surfactant type viscosity reducers have problems such as unstable viscosity reduction effect and poor adaptability to heavy oils with different properties. Although polymer type viscosity reducers have better viscosity reduction effect, their synthesis process is complex, the cost is high, and they are prone to cause environmental pollution.

[0006] As a new type of system, microemulsion has the advantages of ultra-low interfacial tension, good solubilization ability and stability, etc., and has potential application value in the field of heavy oil viscosity reduction. However, there are still some problems in the research of microemulsion-based heavy oil viscosity reducers at present. For example, the formulation of the microemulsion is not optimized enough, and the synergistic effect between components fails to be fully exerted, resulting in unsatisfactory viscosity reduction effect. In addition, the stability of the microemulsion is difficult to guarantee under different reservoir conditions, and it is prone to demulsification and stratification phenomena, affecting the actual application effect of the viscosity reducer. Therefore, it is of great practical significance to develop a highly efficient, stable and adaptable microemulsion-based heavy oil viscosity reducer. Summary of the Invention

[0007] (1) Technical problems to be solved

[0008] In view of the deficiencies of the prior art, the present invention provides a microemulsion-based heavy oil viscosity reducer, its preparation method and application.

[0009] (2) Technical solutions

[0010] A microemulsion-based heavy oil viscosity reducer, characterized in that it is composed of a surfactant, a co-surfactant, an oil phase and a water phase. The surfactant is a compound of a non-ionic gemini surfactant and an anionic fluorocarbon surfactant in a mass ratio of 3:1. The non-ionic gemini surfactant is a polyoxyethylene fatty alcohol ether gemini surfactant, and the specific structural formula is:

[0011]

[0012] where R 1 is an aliphatic alcohol group having 12-18 carbon atoms, n ranges from 5 to 15, representing the number of polyoxyethylene chain segments, and m takes a value of 2-6, representing the number of carbon atoms in the linking group; this structure endows it with unique amphiphilicity and low critical micelle concentration. The anionic fluorocarbon surfactant is potassium perfluorooctane sulfonate, and the specific structural formula is:

[0013]

[0014] Its fluorocarbon chain gives it high surface activity and chemical stability. The co-surfactant is n-butanol. The n-butanol molecule can be inserted between the surfactant molecules to adjust the arrangement of the surfactant molecules, reduce the rigidity of the interface film, and increase the stability of the microemulsion. The oil phase is a light oil, specifically aviation kerosene. Aviation kerosene has low viscosity, high volatility and good solubility, and can be used as a dispersed phase to form a stable microemulsion. The aqueous phase is deionized water containing 0.5%-1.5% (mass fraction) electrolyte, and the electrolyte is sodium chloride. The addition of sodium chloride can adjust the ionic strength of the aqueous phase and affect the arrangement and adsorption behavior of the surfactant molecules at the oil-water interface. The mass percentage of each component is: 5%-10% surfactant, 3%-8% co-surfactant, 15%-25% oil phase, and 60%-77% aqueous phase. This ratio has been optimized through a large number of experiments, and can make each component work synergistically to form a stable and efficient microemulsion structure.

[0015] Preferably, the polyoxyethylene fatty alcohol ether gemini surfactant is subjected to ultrasound-microwave synergistic treatment, the ultrasound frequency is 20-30kHz, the power is 300-500W, and the treatment time is 10-20min. Under the synergistic effect of ultrasound-microwave, the vibration of the molecular bonds inside the molecule is intensified, which can be expressed as:

[0016]

[0017] The cavitation effect of ultrasound will produce local high temperature, high pressure and strong shock waves, while microwaves will cause molecules to vibrate and rotate rapidly. The synergistic effect of the two makes the molecular chains more stretched, the molecular arrangement more regular, the surface activity enhanced, and can more effectively reduce the surface tension of the oil-water interface. Specifically, the surface tension can be reduced from the conventional 30-40mN / m to 10-20mN / m.

[0018] Preferably, the potassium perfluorooctane sulfonate is subjected to a loading treatment, and nano-silicon dioxide is used as a carrier. Nano-silicon dioxide has a high specific surface area, good chemical stability and dispersibility, and is loaded on the nano-silicon dioxide by an impregnation method. The specific operation is to add the nano-silicon dioxide to the solution of potassium perfluorooctane sulfonate, and impregnate it under a certain temperature and stirring conditions. The loading process can be simply expressed as:

[0019]

[0020] The loading amount is 10%-20%. After loading, potassium perfluorooctane sulfonate is fixed on the surface of nano-silica, which improves its dispersibility and stability in the microemulsion system, avoids its agglomeration and precipitation in the system, enhances the synergistic effect with other components, and improves the stability and viscosity reduction performance of the microemulsion.

[0021] Preferably, the preparation method of the microemulsion type heavy oil viscosity reducer comprises the following steps:

[0022] S1, Prepare the aqueous phase: Add sodium chloride to deionized water and stir at a stirring speed of 200 - 300 r / min at room temperature for 15 - 20 min to prepare an aqueous solution containing 0.5% - 1.5% (mass fraction) sodium chloride. A simple dissolution process occurs, and the control of the stirring speed and time can ensure the full dissolution of sodium chloride to form a uniform aqueous phase;

[0023] S2, Treat the surfactants: Subject the polyoxyethylene fatty alcohol ether gemini surfactant to ultrasonic - microwave synergistic treatment, perform the loading treatment on potassium perfluorooctanesulfonate, and then place the two in a mixing container according to a mass ratio of 3:1 and stir at a speed of 150 - 250 r / min for 20 - 30 min to make them fully mixed and uniform;

[0024] S3, Mix each component: Under stirring conditions, sequentially add the treated surfactant, n - butanol, and aviation kerosene to the aqueous phase prepared in step S1. The stirring speed is 300 - 500 r / min, and the stirring time is 30 - 60 min to form a uniform and stable microemulsion - type heavy oil viscosity reducer. During the mixing process, surfactant molecules are oriented at the oil - water interface. Appropriate stirring speed and time can ensure the full mixing of each component to form a microemulsion with uniform particle size and good stability.

[0025] Preferably, the stirring process in S3 adopts intermittent stirring, stirring for 10 min and then pausing for 5 min. Intermittent stirring can allow sufficient time for each component to diffuse and interact, avoiding too high or too low local concentration, which is beneficial to the formation of a stable microemulsion structure. During the pause period, the molecules in the system can rearrange and balance, making the structure of the microemulsion more stable and uniform.

[0026] Preferably, the average particle size of the prepared microemulsion - type heavy oil viscosity reducer is 20 - 50 nm, the particle size distribution is uniform, and it has good thermodynamic stability and kinetic stability. The particle size of the microemulsion is detected and analyzed by methods such as dynamic light scattering to ensure that its particle size is within a suitable range. This uniform small - particle - size structure enables the microemulsion to better disperse in heavy oil and play a viscosity - reducing role, and it is not prone to aggregation and stratification during storage and use.

[0027] Preferably, the microemulsion - type heavy oil viscosity reducer is used for viscosity reduction during heavy oil exploitation and transportation. During heavy oil exploitation, the viscosity reducer is injected into the oil reservoir through an injection well. The surfactant molecules in the viscosity reducer adsorb on the surface of heavy oil droplets, reducing the interfacial tension between the droplets, enabling the droplets to flow more freely, thereby reducing the viscosity of heavy oil and increasing the recovery rate. During transportation, adding the viscosity reducer to heavy oil in a certain proportion can reduce the transportation resistance and energy consumption. For example, it can reduce the pressure drop of the transportation pipeline by 30% - 50%.

[0028] Preferably, when the mass ratio of the microemulsion type heavy oil viscosity reducer to heavy oil is 1:10 - 1:20, the viscosity of heavy oil can be reduced by more than 90%, the viscosity reduction effect is remarkable, and the stable viscosity reduction performance can be maintained for a long time. After a large number of experiments, it is verified that within this mass ratio range, the viscosity reducer can fully play its role, form a stable emulsion system with heavy oil, reduce the internal friction of heavy oil, so as to achieve efficient viscosity reduction. At the same time, due to the stability of the microemulsion, the viscosity reduction effect can remain relatively stable for several days or even weeks, meeting the actual needs of heavy oil exploitation and transportation.

[0029] (III) Beneficial technical effects

[0030] Compared with the existing technologies, the beneficial effects of the present invention are as follows:

[0031] 1. From the perspective of the viscosity reduction effect, when the mass ratio of the viscosity reducer to heavy oil is 1:10 - 1:20, the viscosity of heavy oil can be reduced by more than 90%, and the viscosity reduction effect is extremely remarkable; during the heavy oil exploitation process, the fluidity of heavy oil can be greatly improved, making it easier for heavy oil to flow out of the oil layer, thus significantly improving the recovery rate; compared with the traditional exploitation method, the recovery rate can be increased by 20% - 30%, effectively increasing the oil production.

[0032] 2. In terms of transportation, adding this viscosity reducer can significantly reduce the transportation resistance and energy consumption; the pressure drop of the transportation pipeline can be reduced by 30% - 50%, reducing the energy consumption and equipment wear during transportation, and reducing the transportation cost; at the same time, the stable viscosity reduction effect can effectively avoid pipeline blockage, improving the safety and stability of transportation.

[0033] 3. From the perspective of the performance of the viscosity reducer itself, the polyoxyethylene fatty alcohol ether gemini surfactant adopted in this patent is treated by ultrasonic - microwave synergism, and perfluorooctanesulfonate potassium is treated by loading, which enhances the surface activity of the surfactant and improves its dispersibility and stability in the microemulsion system; the average particle size of the prepared microemulsion type heavy oil viscosity reducer is 20 - 50nm, the particle size distribution is uniform, and it has good thermodynamic stability and kinetic stability, and can maintain stable viscosity reduction performance under different reservoir conditions, having a wide adaptability to heavy oils with different properties.

[0034] 4. The preparation method of this viscosity reducer is simple and easy to implement, the parameters of each step are clear, which is convenient for industrial production; moreover, the raw materials used have wide sources and relatively low costs, having good economic and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is the production flow chart of the microemulsion type heavy oil viscosity reducer;

[0036] Figure 2Test results of viscosity reduction rate and viscosity after viscosity reduction for the comparative example and the examples. Detailed implementation manners

[0037] Example 1

[0038] Preparation of the aqueous phase:

[0039] Add 6.5 g of sodium chloride to 650 g of deionized water, put it into a stirring container, and stir at a speed of 200 r / min for 20 min to fully dissolve the sodium chloride, obtaining an aqueous solution containing 1% (mass fraction) of sodium chloride as the aqueous phase. During the stirring process, closely observe the state of the solution to ensure that there is no obvious particle residue. Treatment of the surfactant:

[0040] Treatment of the polyoxyethylene fatty alcohol ether gemini surfactant: Take 30 g of the polyoxyethylene fatty alcohol ether gemini surfactant, put it into an ultrasonic-microwave synergistic treatment device, set the ultrasonic frequency to 20 kHz, the microwave frequency to 2450 MHz, and the power to 300 W, and treat for 20 min. During the treatment process, the molecules in the device are under the action of ultrasonic cavitation effect and microwave rapid vibration, making the molecular chain more extended and the surface activity enhanced;

[0041] Treatment of potassium perfluorooctanesulfonate: Load 10 g of potassium perfluorooctanesulfonate onto nano-silica by the impregnation method, and control the loading amount at 10%. First, add the nano-silica to the solution of potassium perfluorooctanesulfonate, stir at a speed of 150 r / min at 40 °C for 3 h, and then obtain the loaded potassium perfluorooctanesulfonate through steps such as filtration and drying.

[0042] Mixed surfactant: Put the two treated surfactants into a mixing container and stir at a speed of 150 r / min for 30 min to make them fully and evenly mixed.

[0043] Mixing of each component:

[0044] Under stirring conditions, first add 40 g of the treated surfactant to the aqueous phase, and the stirring speed is 300 r / min. After stirring for 10 min, add 30 g of n-butanol and continue stirring for 10 min. Then add 200 g of aviation kerosene, and use intermittent stirring, stirring for 10 min and then pausing for 5 min. The total stirring time is 60 min, and finally a uniform and stable microemulsion type heavy oil viscosity reducer is formed.

[0045] Test of viscosity reduction effect:

[0046] Take the heavy oil of a certain oilfield, mix the prepared viscosity reducer with the heavy oil at a mass ratio of 1:15, stir evenly at 50 °C, and use a rotational viscometer to measure the viscosity of the heavy oil before and after mixing. After measurement, the viscosity of the heavy oil is reduced from the original 5000 mPa·s to 350 mPa·s, and the viscosity reduction rate reaches 93%.

[0047] Example 2

[0048] Preparation of aqueous phase:

[0049] Add 9.3 g of sodium chloride to 620 g of deionized water and stir at a speed of 250 r / min for 18 min to prepare an aqueous solution containing 1.5% (mass fraction) of sodium chloride. During the stirring process, adjust the stirring speed in a timely manner to ensure the uniformity of the solution.

[0050] Treatment with surfactant:

[0051] Treatment with polyoxyethylene fatty alcohol ether gemini surfactant: Weigh 33 g of polyoxyethylene fatty alcohol ether gemini surfactant, adjust the ultrasonic frequency to 25 kHz, the microwave power to 400 W, and treat for 15 min. After treatment, it is found through a surface tension meter that its surface activity is significantly improved;

[0052] Treatment with potassium perfluorooctanesulfonate: Perform a loading treatment on 11 g of potassium perfluorooctanesulfonate, and the loading amount is 15%; the operating conditions are similar to those in Example 1, but the impregnation temperature is increased to 50 °C and the stirring time is shortened to 2.5 h.

[0053] Mixing of surfactants: Stir the two treated surfactants at a speed of 200 r / min for 25 min.

[0054] Mixing of each component:

[0055] Add 44 g of surfactant, 35 g of n-butanol, and 210 g of aviation kerosene to the aqueous phase in sequence, stir at a speed of 400 r / min, stir intermittently, stir for 10 min and then rest for 5 min, and stir for 50 min to obtain a microemulsion type heavy oil viscosity reducer.

[0056] Testing of viscosity reduction effect:

[0057] Select the heavy oil of another oilfield, mix it with the viscosity reducer at a mass ratio of 1:12, and measure the viscosity at 60 °C; the initial viscosity of the heavy oil is 8000 mPa·s, and it drops to 560 mPa·s after mixing, and the viscosity reduction rate reaches 93%.

[0058] Example 3

[0059] Preparation of aqueous phase:

[0060] Add 3.4 g of sodium chloride to 680 g of deionized water and stir at a speed of 300 r / min for 15 min to obtain an aqueous solution containing 0.5% (mass fraction) of sodium chloride. Pay attention to observing the transparency of the solution during stirring. Treatment with surfactant:

[0061] Treatment with polyoxyethylene fatty alcohol ether gemini surfactant: Take 27 g of polyoxyethylene fatty alcohol ether gemini surfactant, with an ultrasonic frequency of 30 kHz, a microwave power of 500 W, and treat for 10 min. After treatment, its adsorption capacity at the oil-water interface is enhanced.

[0062] Treatment with potassium perfluorooctane sulfonate: Perform a loading treatment on 9 g of potassium perfluorooctane sulfonate, with a loading amount of 20%. The impregnation temperature is 60 °C, and the stirring time is 2 h.

[0063] Mixed surfactant: Stir the two treated surfactants at a speed of 250 r / min for 20 min.

[0064] Mix each component:

[0065] Add 36 g of surfactant, 24 g of n-butanol, and 160 g of aviation kerosene to the aqueous phase, stir at a speed of 500 r / min, with intermittent stirring, and stir for 30 min to prepare a microemulsion type heavy oil viscosity reducer.

[0066] Viscosity reduction effect test:

[0067] Use the heavy oil from another oilfield, mix it with the viscosity reducer at a mass ratio of 1:20, and measure the viscosity at 40 °C. The initial viscosity is 3000 mPa·s, and after mixing, it is 210 mPa·s, with a viscosity reduction rate of 93%.

[0068] Comparative example

[0069] Preparation of viscosity reducer:

[0070] Directly mix 30 g of untreated polyoxyethylene fatty alcohol ether gemini surfactant and 10 g of potassium perfluorooctane sulfonate, add 30 g of n-butanol, 200 g of aviation kerosene, and 650 g of deionized water containing 1% sodium chloride, and continuously stir at a speed of 300 r / min for 60 min to prepare a viscosity reducer.

[0071] Viscosity reduction effect test:

[0072] Select the same oilfield heavy oil as in Example 1, mix it with the viscosity reducer at a mass ratio of 1:15, measure the viscosity at 50 °C, the initial viscosity of the heavy oil is 5000 mPa·s, and after mixing, it drops to 1200 mPa·s, with a viscosity reduction rate of 76%.

[0073] It can be seen from the above three examples and one comparative example that the surfactant treatment method, intermittent stirring process, etc. adopted in this patent can significantly improve the viscosity reduction effect of the microemulsion type heavy oil viscosity reducer, and have obvious advantages.

[0074] Comparison table of process conditions between examples and comparative examples:

[0075]

[0076] Conclusion: As can be seen from the table, there are obvious differences between the examples and the comparative examples in process conditions such as surfactant treatment, loading amount, and stirring method. The examples have carried out special treatment on the surfactant and adopted intermittent stirring. These optimized process conditions lay the foundation for the subsequent improvement of the viscosity reduction effect, indicating that reasonable process settings have an important impact on the performance of the viscosity reducer.

[0077] Comparison table of the viscosity reduction effects of the examples and the comparative examples:

[0078]

[0079] Conclusion: By comparing the viscosity reduction effect data of the examples and the comparative examples, it can be seen that the viscosity reduction rates of the examples all reach 93%, while that of the comparative examples is only 76%. This fully proves that the surfactant treatment method, the loading process, and the intermittent stirring method adopted in this patent can significantly improve the viscosity reduction effect of the microemulsion-type heavy oil viscosity reducer, highlighting the advantages of this process.

[0080] Comparison table of the surfactant performance under different treatment methods:

[0081]

[0082] Conclusion: This table compares the surfactant performance after treatment in the examples and untreated in the comparative examples. It can be found that after treatment, the performance of the surfactant has been significantly improved. The surface activity and adsorption ability of the polyoxyethylene fatty alcohol ether gemini surfactant are enhanced, and the dispersion and stability of potassium perfluorooctane sulfonate are improved. These performance improvements provide a guarantee for the high-efficiency viscosity reduction of the viscosity reducer, further illustrating the importance of the surfactant treatment process.

[0083] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A microemulsion type heavy oil viscosity reducer, characterized in that: The invention is composed of a surfactant, a co-surfactant, an oil phase and an aqueous phase. The surfactant is a compound of a non-ionic gemini surfactant and an anionic fluorocarbon surfactant in a mass ratio of 3:

1. The non-ionic gemini surfactant is a polyoxyethylene fatty alcohol ether gemini surfactant, and the specific structural formula is: Wherein R1 is a fatty alcohol group having 12-18 carbon atoms, n is in the range of 5-15, representing the number of polyoxyethylene chain segments, and m is in the range of 2-6, representing the number of carbon atoms in the linking group; The anionic fluorocarbon surfactant is potassium perfluorooctane sulfonate, and the specific structural formula is: The auxiliary surfactant is n-butanol, and the n-butanol molecules can be inserted between the surfactant molecules to adjust the arrangement of the surfactant molecules; the oil phase is light oil, and the water phase is deionized water containing 0.5%-1.5% by mass of electrolyte, the electrolyte is sodium chloride, and the mass percentages of the components are: 5%-10% of surfactant, 3%-8% of auxiliary surfactant, 15%-25% of oil phase, and 60%-77% of water phase.

2. The microemulsion type heavy oil viscosity reducer according to claim 1, characterized in that: The polyoxyethylene fatty alcohol ether gemini surfactant is subjected to ultrasound-microwave synergistic treatment, with an ultrasound frequency of 20-30kHz, a power of 300-500W, and a treatment time of 10-20min. Under the synergistic effect of ultrasound-microwave, the vibration of the molecular bonds inside the molecule is intensified, which is specifically expressed as follows: The cavitation effect of ultrasound will produce local high temperature, high pressure and strong shock waves, while microwaves will cause molecules to vibrate and rotate rapidly. The synergistic effect of the two makes the molecular chains more stretched and can more effectively reduce the surface tension of the oil-water interface. Specifically, the surface tension can be reduced from the conventional 30-40mN / m to 10-20mN / m.

3. The microemulsion type heavy oil viscosity reducer according to claim 1, characterized in that: The potassium perfluorooctane sulfonate is subjected to a loading treatment and loaded on the nano-silicon dioxide by an impregnation method with the nano-silicon dioxide as a carrier. The loading process can be simply expressed as follows: The loading amount is 10%-20%. After loading, potassium perfluorooctane sulfonate is fixed on the surface of nano-silicon dioxide, thereby improving its dispersibility and stability in the microemulsion system.

4. A method for preparing the microemulsion type heavy oil viscosity reducer according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, preparing an aqueous phase: adding sodium chloride to deionized water, stirring at a stirring speed of 200-300 r / min for 15-20 min at room temperature to prepare an aqueous solution containing 0.5%-1.5% sodium chloride, and stirring sufficiently to ensure that the sodium chloride is fully dissolved to form a uniform aqueous phase; S2, treating surfactants: subjecting the polyoxyethylene fatty alcohol ether gemini surfactant to ultrasonic-microwave synergistic treatment, subjecting potassium perfluorooctane sulfonate to loading treatment, and then placing the two in a mixing container at a mass ratio of 3:1, stirring at a speed of 150-250 r / min for 20-30 min to fully mix them; S3, mixing the components: under stirring conditions, sequentially adding the treated surfactant, n-butanol, and aviation kerosene to the water phase prepared in step S1 at a stirring speed of 300-500 r / min for 30-60 min to form a uniform and stable microemulsion type heavy oil viscosity reducer.

5. The method for preparing the microemulsion type heavy oil viscosity reducer according to claim 4, characterized in that: The stirring process in S3 adopts intermittent stirring, stirring for 10 minutes and resting for 5 minutes. Intermittent stirring can give each component enough time to diffuse and interact with each other, avoiding excessively high or low local concentrations.

6. The method for preparing the microemulsion type heavy oil viscosity reducer according to claim 4, characterized in that: The prepared microemulsion type heavy oil viscosity reducer has an average particle size of 20-50nm, a uniform particle size distribution, good thermodynamic stability and kinetic stability, and the particle size of the microemulsion is detected and analyzed by dynamic light scattering to ensure that the particle size is within a suitable range.

7. Use of the microemulsion type heavy oil viscosity reducer according to any one of claims 1 to 3 or the microemulsion type heavy oil viscosity reducer prepared by the preparation method according to any one of claims 4 to 6, characterized in that: Used for viscosity reduction during heavy oil production and transportation. During heavy oil production, the viscosity reducer is injected into the oil layer through the injection well. The surfactant molecules in the viscosity reducer are adsorbed on the surface of the oil droplets of the heavy oil to reduce the interfacial tension between the oil droplets. During the transportation process, the viscosity reducer is added to the heavy oil in a certain proportion to reduce the transportation resistance.

8. The use according to claim 7, characterized in that: When the mass ratio of the microemulsion type heavy oil viscosity reducer to the heavy oil is 1:10-1:20, the viscosity of the heavy oil can be reduced by more than 90%, the viscosity reduction effect is significant, and the stable viscosity reduction performance can be maintained for a long time. Within this mass ratio range, the viscosity reducer can form a stable emulsion system with the heavy oil to reduce the internal friction of the heavy oil. At the same time, due to the stability of the microemulsion, the viscosity reduction effect can remain relatively stable for several days or even weeks.

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