Thickened oil nano emulsifying viscosity reducer and application thereof

Abstract

The invention relates to a thick oil nano-emulsification viscosity reducer and application thereof, and belongs to the technical field of oil exploitation. The viscosity reducer comprises the following components: a modified nano material, an anionic surfactant, a nonionic surfactant, an alkaline substance and a solvent, wherein the modified nano material has small size and high surface activity, and can improve the firmness of an oil-water interface film, increase the stability of the emulsion and reduce the interfacial tension of an oil-water interface; the surfactant can improve the surface activity of water, reduce the interfacial tension between oil and water and promote the dispersion and emulsification of thickened oil; the alkaline substances can react with naphthenic acid, fatty acid, asphaltene acid and colloidal acid in the thickened oil, so that the acidic substances are in situ or converted into a surfactant; all the substances are mutually cooperated, so that the viscosity reduction effect on the thick oil is improved.

Description

Technical Field

[0001] The present application relates to the technical field of petroleum extraction, and in particular to a heavy oil nanoemulsification viscosity reducer and its application. Background Art

[0002] With the massive and continuous consumption of conventional oil resources, the urgency of developing and utilizing heavy oil resources has become increasingly prominent. Heavy oil has the characteristics of high viscosity, high density and poor fluidity due to the presence of a large amount of heavy components such as asphaltene and colloid, which makes it difficult to mine and transport and has poor resource utilization. How to reduce the viscosity of heavy oil and improve its fluidity has become the key to its development and utilization.

[0003] The Bayan Oilfield has a loose sandy conglomerate reservoir, where the formation crude oil has high viscosity and poor fluidity, and has a large drag force on the formation sand particles. There is a risk of sand production during the heavy oil production process. While fracturing measures are being used to increase production, it is necessary to consider reducing the viscosity of the reservoir crude oil and inject high-efficiency viscosity reducers at the front to achieve the effect of fracturing and sand prevention.

[0004] At present, the main technologies used for viscosity reduction are heating viscosity reduction, thin oil mixing viscosity reduction, water-based emulsified viscosity reducer viscosity reduction, oil-based viscosity reducer chemical viscosity reduction, catalytic cracking viscosity reduction and microbial viscosity reduction. The common composition of water-based emulsified viscosity reducer is surfactant and compounding agent. Due to its high viscosity reduction rate, low cost and easy operation, it is currently widely used at home and abroad. For example, Chinese invention patent application CN 101148580A discloses a high temperature and high salt resistant nano-emulsified viscosity reducer. In order to overcome the shortcomings of single use of surfactant steam injection, small viscosity reduction amplitude and short cycle, the organic acid in crude oil is used to reduce the amount of surfactant. At the same time, the addition of alkaline additives and nano additives (ZnO or CaCO3) produces a synergistic effect with emulsified viscosity reduction, achieving a significant improvement in the effect of emulsified viscosity reduction. Chinese invention patent application CN 111394080A discloses a method for using a heavy oil viscosity reducer, which is simple to operate, can effectively reduce the viscosity of heavy oil, is convenient for post-processing and has low cost. The heavy oil viscosity reducer includes graphene oxide, surfactant, oil-soluble polymer, alkali, etc. However, there is still room for improvement in the viscosity reduction effect on heavy oil. Summary of the invention

[0005] The present application provides a heavy oil nanoemulsification viscosity reducer and application thereof to improve the viscosity reduction effect on heavy oil.

[0006] In a first aspect, the present application provides a heavy oil nanoemulsification viscosity reducer, wherein the viscosity reducer ingredients include modified nanomaterials, anionic surfactants, nonionic surfactants, alkaline substances and solvents.

[0007] As an optional implementation, the viscosity reducer comprises, by mass fraction, 1% to 3% of modified nanomaterials, 40% to 50% of anionic surfactants, 6% to 8% of nonionic surfactants, 15% to 25% of alkaline substances, and the rest being solvents.

[0008] As an optional implementation, the viscosity reducer comprises, by mass fraction, 1.5% to 2.5% of modified nanomaterials, 43% to 47% of anionic surfactants, 6.5% to 7.5% of nonionic surfactants and 18% to 22% of alkaline substances, with the remainder being solvent.

[0009] As an optional implementation manner, the modified nanomaterial is prepared by modifying the nanomaterial via a modifier; and / or

[0010] The nanomaterial comprises at least one of graphene, boron nitride and molybdenum disulfide; and / or

[0011] The modifier includes at least one of polyvinyl pyrrolidone, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and polydiallyl dimethyl ammonium chloride.

[0012] As an optional embodiment, the anionic surfactant includes petroleum sulfonate and / or sulfate; the petroleum sulfonate includes at least one of alkylmethylnaphthalene sulfonate, alkylbenzene sulfonate, sodium dodecylbenzene sulfonate, sodium hexadecylbenzene sulfonate and alkylglycerol sulfonate; the sulfate includes at least one of alcohol alkoxy sulfate, tristyrylphenol alkoxy sulfonate, alkyl ether sulfate and dodecyl sulfate.

[0013] As an optional embodiment, the nonionic surfactant includes at least one of polyoxyethylene dodecylphenol ether, polyoxyethylene sorbitan monostearate, polyoxyethylene fatty alcohol ether and sorbitan fatty acid ester.

[0014] As an optional embodiment, the alkaline substance includes at least one of sodium hydroxide, sodium silicate, sodium bicarbonate, sodium carbonate, potassium hydroxide and triethanolamine.

[0015] In a second aspect, the present application provides a method for reducing the viscosity of heavy oil, the method comprising:

[0016] Obtaining the viscosity reducing agent described in the first aspect;

[0017] dispersing the viscosity reducing agent in a solvent to obtain a viscosity reducing agent solution;

[0018] The viscosity reducer solution and the heavy oil are mixed so that the viscosity reducer solution and the heavy oil form a uniform, stable and low-viscosity emulsion to achieve viscosity reduction.

[0019] As an optional implementation manner, in the viscosity reducer solution, the viscosity reducer accounts for 0.5% to 2% of the mass of the solvent.

[0020] As an optional embodiment, the mixing mass ratio of the viscosity reducer solution to the heavy oil is (3-7):7; and / or

[0021] The temperature of the mixture of the viscosity reducer solution and the heavy oil is 50-70°C.

[0022] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0023] The viscosity reducer provided in the embodiment of the present application comprises modified nanomaterials, anionic surfactants, nonionic surfactants and alkaline substances, wherein the modified nanomaterials have a small size and high surface activity, can improve the firmness of the oil-water interface film, increase the stability of the emulsion, and reduce the interfacial tension of the oil-water interface; the surfactant can improve the surface activity of water, reduce the interfacial tension between oil and water, and promote the dispersion and emulsification of heavy oil; the alkaline substance can react with cyclohexane acid, fatty acid, asphalt acid and colloidal acid in the heavy oil, so that these acidic substances are in situ or converted into surfactants; the above substances work together to enhance the viscosity reduction effect on heavy oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0026] Figure 1 A flowchart of a method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0028] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0029] The embodiment of the present application provides a thick oil nanoemulsification viscosity reducer, wherein the viscosity reducer comprises a modified nanomaterial, an anionic surfactant, a nonionic surfactant, an alkali substance and a solvent. The solvent may be selected from water. The modified nanomaterial comprises a two-dimensional nanomaterial, such as modified graphene, modified boron nitride, and modified molybdenum disulfide.

[0030] Modified nanomaterials are two-dimensional nanomaterials. After modification, the distribution from the edge to the middle of the sheet material is hydrophilic to hydrophobic. Gel asphaltene is an aggregate of sheet structures, similar to the structure of the modified nanomaterials above. When the heavy oil is emulsified with the viscosity reducer solution to form a solution, the aggregate structure of the gel asphaltene will become loose. The modified nanomaterials can be inserted between the aggregates, destroying the stacking structure of the gel asphaltene, making it difficult for the gel asphaltene to restack. Nanomaterials have small size and strong surface activity, and will be adsorbed at the oil-water interface, thereby reducing the oil-water interfacial tension and making the oil-water interfacial film more stable.

[0031] Surfactants are the most important type of water-soluble heavy oil viscosity reducers. They can increase the surface activity of water, reduce the interfacial tension between oil and water, promote the dispersion and emulsification of heavy oil, and are widely used in heavy oil viscosity reduction.

[0032] Since reservoir clay is mostly negatively charged and repels anionic surfactants, it can reduce the adsorption of surfactants in the reservoir. Therefore, anionic surfactants are the most commonly used surfactant-type water-soluble heavy oil viscosity reducers; anionic surfactants include petroleum sulfonates and / or sulfates; wherein the petroleum sulfonates can be selected from at least one of alkyl methyl naphthalene sulfonates, alkyl benzene sulfonates, sodium dodecyl benzene sulfonate, sodium hexadecyl benzene sulfonate and alkyl glycerol sulfonates; the sulfate can be selected from at least one of alcohol alkoxy sulfates, tristyrylphenol alkoxy sulfonates, alkyl ether sulfates and dodecyl sulfates.

[0033] The hydrophilic group of the nonionic surfactant is mainly composed of a certain number of oxygen-containing groups, which do not dissociate in water, so they are not easily affected by the presence of strong electrolytes, have good salt resistance, and are not easily affected by acidity and alkalinity. The nonionic surfactant includes at least one of polyoxyethylene dodecylphenol ether (OP-10), polyoxyethylene sorbitan monostearate (Tween-60), polyoxyethylene fatty alcohol ether (BS-12) and sorbitan fatty acid ester (OA-7).

[0034] Since heavy oil usually contains cyclohexane acid, fatty acid, asphaltic acid and colloidal acid, these acidic substances can be in situ or transformed into surfactants under the action of alkali, so alkali is also an important water-soluble heavy oil viscosity reducer. Alkali substances include at least one of sodium hydroxide, sodium silicate, sodium bicarbonate, sodium carbonate, potassium hydroxide and triethanolamine.

[0035] In some embodiments, the modified nanomaterial is a nanomaterial modified by a modifier; specifically, the unmodified nanomaterial and the modifier are added to a ball mill at a ratio of 5:1, and the modified nanomaterial is obtained by ball milling at a speed of 800 rpm for 12 hours, and the modified nanomaterial is washed and filtered with deionized water and anhydrous ethanol, and placed in a drying oven at a temperature of 70°C to obtain a hydrophilic modified nanomaterial. Among them, the nanomaterial can be selected from at least one of graphene, boron nitride and molybdenum disulfide; the modifier can be selected from at least one of polyvinyl pyrrolidone, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and polydiallyldimethylammonium chloride. That is, the modified nanomaterial can be modified graphene, modified boron nitride, and modified molybdenum disulfide.

[0036] In some embodiments, the viscosity reducer comprises, by mass fraction, 1% to 3% of modified nanomaterials, 40% to 50% of anionic surfactants, 6% to 8% of nonionic surfactants, and 15% to 25% of alkaline substances, with the remainder being solvent. Further, the viscosity reducer comprises, by mass fraction, 1.5% to 2.5% of modified nanomaterials, 43% to 47% of anionic surfactants, 6.5% to 7.5% of nonionic surfactants, and 18% to 22% of alkaline substances, with the remainder being solvent.

[0037] Figure 1 A flowchart of the method provided in the embodiment of the present application, such as Figure 1 As shown, based on a general inventive concept, the present application embodiment also provides a method for reducing the viscosity of heavy oil, the method comprising:

[0038] S1. Obtaining the viscosity reducing agent provided above;

[0039] Specifically, in this embodiment, the modified nanomaterial is put into water and ultrasonically dispersed for 30 minutes to 60 minutes to make it evenly dispersed. Anionic surfactants, nonionic surfactants and alkaline substances are put into the above liquid, and an agitator is used to disperse the above agents evenly at a speed of 200rpm-300rpm.

[0040] S2. dispersing the viscosity reducing agent in a solvent to obtain a viscosity reducing agent solution;

[0041] In some embodiments, in the viscosity reducer solution, the viscosity reducer accounts for 0.5% to 2% of the mass of the solvent.

[0042] Specifically, in this embodiment, the heavy oil nano-emulsified viscosity reducer is dispersed in water at a mass fraction of 0.5% to 2% to prepare a viscosity reducer solution.

[0043] S3. The viscosity reducer solution and the heavy oil are mixed so that the viscosity reducer solution and the heavy oil form a uniform, stable and low-viscosity emulsion to achieve viscosity reduction.

[0044] In some embodiments, the mixing mass ratio of the viscosity reducer solution and the heavy oil is (3-7):7; the mixing temperature of the viscosity reducer solution and the heavy oil is 50°C-70°C.

[0045] Specifically, in this embodiment, the heavy oil is heated to 50°C to 70°C and kept heated for 4h-6h, and the above viscosity reducer solution and the degassed and dehydrated heavy oil are stirred at a ratio of 3 to 7:7 at 50°C to 70°C and a speed of 500rpm-1000rpm for 30min to 60min, so that the viscosity reducer solution and the heavy oil form a uniform, stable and low-viscosity emulsion.

[0046] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0047] Example 1

[0048] A method for reducing the viscosity of heavy oil, the method comprising:

[0049] ① Put 1% modified boron nitride by mass into 38% water, use ultrasonic dispersion for 45 minutes to make it evenly dispersed, put 40% sodium dodecylbenzene sulfonate, 6% dodecylphenol polyoxyethylene ether, and 15% sodium hydroxide into the above liquid, and use a stirrer at a speed of 250rpm to evenly disperse the above agents;

[0050] ② Dispersing the heavy oil nanoemulsified viscosity reducer obtained in ① in water at a mass fraction of 1% to prepare a viscosity reducer solution;

[0051] ③ Heat the heavy oil to 60°C and keep heating for 4 hours. Stir the above viscosity reducer solution and degassed and dehydrated heavy oil at a ratio of 3:7 at 60°C and a speed of 800 rpm for 40 minutes to form a uniform, stable and low-viscosity emulsion with the viscosity reducer solution and the heavy oil.

[0052] Example 2

[0053] A method for reducing the viscosity of heavy oil, the method comprising:

[0054] ① Put 0.5% modified graphene by mass into 21.5% water, use ultrasonic dispersion for 60 minutes to make it evenly dispersed, put 50% dodecyl sulfate, 8% polyoxyethylene sorbitan monostearate, and 20% sodium carbonate into the above liquid, and use a stirrer at a speed of 300rpm to evenly disperse the above agents;

[0055] ② Dispersing the heavy oil nanoemulsified viscosity reducer obtained in ① in water at a mass fraction of 1.5% to prepare a viscosity reducer solution;

[0056] ③ Heat the heavy oil to 70°C and keep heating for 6 hours. Stir the above viscosity reducer solution and degassed and dehydrated heavy oil at a ratio of 5:7 at 70°C and a speed of 500 rpm for 30 minutes to form a uniform, stable and low-viscosity emulsion with the viscosity reducer solution and the heavy oil.

[0057] Example 3

[0058] A method for reducing the viscosity of heavy oil, the method comprising:

[0059] ① Add 1.5% modified molybdenum disulfide by mass into 21.5% water, use ultrasonic dispersion for 30 minutes to make it evenly dispersed, add 45% alkyl glycerol sulfonate, 7% fatty alcohol polyoxyethylene ether, and 25% potassium hydroxide into the above liquid, and use a stirrer at a speed of 200 rpm to evenly disperse the above agents;

[0060] ② Dispersing the heavy oil nanoemulsified viscosity reducer obtained in ① in water at a mass fraction of 2% to prepare a viscosity reducer solution;

[0061] ③ Heat the heavy oil to 50°C and keep heating for 5 hours. Stir the above viscosity reducer solution and degassed and dehydrated heavy oil at a ratio of 7:7 at 50°C and a speed of 900 rpm for 60 minutes to form a uniform, stable and low-viscosity emulsion with the viscosity reducer solution and the heavy oil.

[0062] Comparative Example 1

[0063] A method for reducing the viscosity of heavy oil, the method comprising:

[0064] ① Add 40% sodium dodecylbenzene sulfonate, 6% dodecylphenol polyoxyethylene ether, and 15% sodium hydroxide into 39%

[0065] In water, use a stirrer at a speed of 250 rpm to evenly disperse the above agents;

[0066] ② Dispersing the heavy oil nanoemulsified viscosity reducer obtained in ① in water at a mass fraction of 1% to prepare a viscosity reducer solution;

[0067] ③ Heat the heavy oil to 60°C and keep heating for 4 hours. Stir the above viscosity reducer solution and degassed and dehydrated heavy oil at a ratio of 3:7 at 60°C and a speed of 800 rpm for 40 minutes to form a uniform, stable and low-viscosity emulsion with the viscosity reducer solution and the heavy oil.

[0068] Comparative Example 2

[0069] A method for reducing the viscosity of heavy oil, the method comprising:

[0070] ① Add 50% dodecyl sulfate, 8% polyoxyethylene sorbitan monostearate, and 20% sodium carbonate into 22% water, and use a stirrer at a speed of 300 rpm to evenly disperse the above agents;

[0071] ② Dispersing the heavy oil nanoemulsified viscosity reducer obtained in ① in water at a mass fraction of 1.5% to prepare a viscosity reducer solution;

[0072] ③ Heat the heavy oil to 70°C and keep heating for 6 hours. Stir the above viscosity reducer solution and degassed and dehydrated heavy oil at a ratio of 5:7 at 70°C and a speed of 500 rpm for 30 minutes to form a uniform, stable and low-viscosity emulsion with the viscosity reducer solution and the heavy oil.

[0073] Comparative Example 3

[0074] A method for reducing the viscosity of heavy oil, the method comprising:

[0075] ① Add 45% alkyl glycerol sulfonate, 7% fatty alcohol polyoxyethylene ether, and 25% potassium hydroxide into 23% water, and use a stirrer at a speed of 200 rpm to evenly disperse the above agents;

[0076] ② Dispersing the heavy oil nanoemulsified viscosity reducer obtained in ① in water at a mass fraction of 2% to prepare a viscosity reducer solution;

[0077] ③ Heat the heavy oil to 50°C and keep heating for 5 hours. Stir the above viscosity reducer solution and degassed and dehydrated heavy oil at a ratio of 7:7 at 50°C and a speed of 900 rpm for 60 minutes to form a uniform, stable and low-viscosity emulsion with the viscosity reducer solution and the heavy oil.

[0078] The heavy oil emulsification viscosity reduction performance after the operation of the methods provided in Examples 1 to 3 and Comparative Examples 1 to 3 was tested, and the testing process included: using a DV-II+PRO rotational viscometer (Brookfield) to test the apparent viscosity of each emulsion, and calculating the corresponding heavy oil viscosity reduction rate according to the following formula.

[0079] DVR%=(ηr-ηc)*100 / ηr

[0080] Where ηr represents the apparent viscosity of the heavy oil sample, and ηc represents the apparent viscosity of the sample after emulsification and viscosity reduction.

[0081] The results are shown in the following table:

[0082]

[0083]

[0084] It can be seen from the above table that the viscosity reducing agent provided in the embodiments of the present application has a higher viscosity reducing effect than the traditional aqueous viscosity reducing agent, and has a better heavy oil viscosity reducing effect.

[0085] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0086] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[0087] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A thick oil nanoemulsification viscosity reducer, characterized in that: The viscosity reducing agent components include modified nanometer materials, anionic surfactants, nonionic surfactants, alkaline substances and solvents.

2. The thick oil nanoemulsification viscosity reducer according to claim 1, characterized in that: The viscosity reducer comprises, by mass fraction, 1% to 3% of modified nanometer material, 40% to 50% of anionic surfactant, 6% to 8% of nonionic surfactant and 15% to 25% of alkaline substance, and the rest is solvent.

3. The thick oil nanoemulsification viscosity reducer according to claim 1, characterized in that: The viscosity reducer comprises, by mass fraction, 1.5% to 2.5% of modified nanometer material, 43% to 47% of anionic surfactant, 6.5% to 7.5% of nonionic surfactant and 18% to 22% of alkaline substance, and the rest is solvent.

4. The thick oil nanoemulsification viscosity reducer according to any one of claims 1 to 3, characterized in that: The modified nanomaterial is prepared by modifying the nanomaterial with a modifier; and / or The nanomaterial comprises at least one of graphene, boron nitride and molybdenum disulfide; and / or The modifier includes at least one of polyvinyl pyrrolidone, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and polydiallyl dimethyl ammonium chloride.

5. The thick oil nanoemulsification viscosity reducer according to any one of claims 1 to 3, characterized in that: The anionic surfactant includes petroleum sulfonate and / or sulfate; the petroleum sulfonate includes at least one of alkylmethylnaphthalene sulfonate, alkylbenzene sulfonate, sodium dodecylbenzene sulfonate, sodium hexadecylbenzene sulfonate and alkylglycerol sulfonate; the sulfate includes at least one of alcohol alkoxy sulfate, tristyrylphenol alkoxy sulfonate, alkyl ether sulfate and dodecyl sulfate.

6. The thick oil nanoemulsification viscosity reducer according to any one of claims 1 to 3, characterized in that: The nonionic surfactant includes at least one of polyoxyethylene dodecylphenol ether, polyoxyethylene sorbitan monostearate, polyoxyethylene fatty alcohol ether and sorbitan fatty acid ester.

7. The thick oil nanoemulsification viscosity reducer according to any one of claims 1 to 3, characterized in that: The alkaline substance includes at least one of sodium hydroxide, sodium silicate, sodium bicarbonate, sodium carbonate, potassium hydroxide and triethanolamine.

8. A method for reducing the viscosity of heavy oil, characterized in that: The method comprises: Obtaining the viscosity reducer according to any one of claims 1 to 7; dispersing the viscosity reducing agent in a solvent to obtain a viscosity reducing agent solution; The viscosity reducer solution and the heavy oil are mixed so that the viscosity reducer solution and the heavy oil form a uniform, stable and low-viscosity emulsion to achieve viscosity reduction.

9. The method for reducing the viscosity of heavy oil according to claim 8, characterized in that: In the viscosity reducer solution, the viscosity reducer accounts for 0.5% to 2% of the mass of the solvent.

10. The method for reducing the viscosity of heavy oil according to claim 8, characterized in that: The mixing mass ratio of the viscosity reducer solution to the heavy oil is (3-7):7; and / or The temperature of the mixture of the viscosity reducer solution and the heavy oil is 50-70°C.

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