A nano black phosphorus thick oil viscosity reducer, a preparation method and application thereof

Abstract

The application discloses a nano black phosphorus thick oil viscosity reducer, a preparation method and application thereof. The preparation raw material of the nano black phosphorus thick oil viscosity reducer comprises oil-soluble polymer modified molybdenum disulfide nanosheet, black phosphorus nanosheet and a coupling agent, and the mass ratio of the oil-soluble polymer modified molybdenum disulfide nanosheet, the black phosphorus nanosheet and the coupling agent is 1:2:2-6. The nano black phosphorus thick oil viscosity reducer has strong asphaltene interaction force, high viscosity reduction rate, good temperature resistance and salt resistance, good crude oil compatibility and is not prone to aggregation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil exploitation, and particularly relates to a nano black phosphorus viscous oil viscosity reducer, a preparation method and application thereof. BACKGROUND

[0002] Viscous oil accounts for more than half of the world's recoverable oil reserves. With the gradual increase in demand for oil resources in the global energy market, the exploitation of viscous oil has been widely valued by countries around the world. The classification standard of viscous oil in China classifies crude oil with a viscosity greater than 50000 mPa·s and a density greater than 0.98 g / cm 3 as super viscous oil; and classifies crude oil with a viscosity of 10000-50000 mPa·s and a density greater than 0.95 g / cm 3 as super viscous oil. Compared with ordinary viscous oil (viscosity less than 10000 mPa·s), super viscous oil has higher resin and asphalt content, higher viscosity and poorer flowability, which is not conducive to exploitation.

[0003] At present, the main methods for exploiting viscous oil are thermal exploitation, mixing with light oil to reduce viscosity and chemical viscosity reduction. Chemical viscosity reduction is considered to be the most promising exploitation method. This method is simple to operate, energy-saving and consumption-reducing, and is an important way to improve economic benefits. Chemical viscosity reducers are mainly divided into water-soluble viscosity reducers and oil-soluble viscosity reducers. Water-soluble viscosity reducers mainly disperse viscous oil into oil-in-water emulsion through emulsification, thereby reducing the viscosity of viscous oil, but there is a problem of dehydration difficulty in post-processing. Oil-soluble viscosity reducers form hydrogen bonds between strong polar functional groups on the molecules of the viscosity reducer and resin and asphalt, disperse asphalt aggregates, and achieve the effect of reducing the viscosity of viscous oil. Because oil-soluble viscosity reducers can directly mix with crude oil to improve the flowability of crude oil and do not have the problem of post-processing, oil-soluble viscosity reducers have attracted people's attention at present.

[0004] Chen Ningning (Synthesis and Performance Research of New Polymeric Oil-soluble Viscous Oil Viscosity Reducer [J]. Chemical Reagents, 2017, 39(2): 4.) discloses a quaternary copolymer oil-soluble polymer as a viscous oil viscosity reducer. Research shows that when 10% of the viscous oil viscosity reducer is added under the condition of 50℃, the viscosity reduction rate is 88.1%.

[0005] Chen Xiaokai (Synthesis and Performance Evaluation of Oil-soluble Viscosity Reducer SA / MMA / VTEO Copolymer [J]. Chemical Engineer, 2016(7): 5.) adopts three monomers of octadecyl acrylate, vinyl triethoxysilane and methyl methacrylate for ternary copolymerization. Experimental results show that the viscosity reduction rate can be more than 80% under the condition of 50℃.

[0006] With the wide application of nanomaterials in the field of oil and gas field development, the research on the synthesis of heavy oil viscosity reducer by using nanomaterials has attracted the attention of researchers. Zhang Liqun (Indoor Research and Evaluation of Heavy Oil Nano Viscosity Reducer [J]. Chemical and Biological Engineering, 2022, 39 (1): 52-54.) developed a kind of heavy oil nano viscosity reducer MLA for water-based drilling fluid, which can reduce the viscosity of heavy oil emulsion. When the water content of heavy oil is 20%, the viscosity reduction rate at 75℃ is more than 60%.

[0007] The current oil-soluble heavy oil viscosity reducer is generally a high molecular polymer, and its synthesis process is complex and is easily affected by factors such as reservoir temperature and salinity. Moreover, the contact area of spherical nanoparticles with asphaltene is small, and the intermolecular van der Waals force is weak, which affects the effect of heavy oil viscosity reduction. It is an urgent practical problem to develop a new type of nano viscosity reducer for heavy oil, which has a large contact area and strong interaction with asphaltene. SUMMARY

[0008] In view of the above problems, the present application provides a kind of nano black phosphorus heavy oil viscosity reducer, its preparation method and application. The viscosity reducer has strong interaction with asphaltene, good temperature and salt resistance, good compatibility with crude oil and is not easy to aggregate.

[0009] In one aspect of the present application, a nano black phosphorus heavy oil viscosity reducer is provided, and the preparation raw materials include: oil-soluble polymer modified molybdenum disulfide nanosheet, black phosphorus nanosheet and coupling agent. The mass ratio of the oil-soluble polymer modified molybdenum disulfide nanosheet, the black phosphorus nanosheet and the coupling agent is 1:2:2-6.

[0010] As a specific embodiment of the present application, the oil-soluble polymer modified molybdenum disulfide nanosheet has a continuous phase comprising an oil-soluble polymer, and a dispersed phase comprising molybdenum disulfide nanosheets dispersed in the continuous phase.

[0011] As a specific embodiment of the present application, the polymer monomer of the oil-soluble polymer forming the continuous phase is selected from one or more than two combinations of acrylamide, styrene, divinylbenzene, eicosyl methacrylate, docosyl methacrylate and tetracosyl methacrylate; preferably a combination of acrylamide, styrene, eicosyl methacrylate and tetracosyl methacrylate; more preferably a combination of acrylamide, styrene, eicosyl methacrylate and tetracosyl methacrylate in a mass ratio of 2-3:7-8:42-43:48-49.

[0012] As a specific embodiment of the present application, the molybdenum disulfide nanosheet forming the dispersed phase is selected from molybdenum disulfide nanosheets with a crystal type of 1T, and the size of the molybdenum disulfide nanosheet is 100-200 nm.

[0013] As a specific embodiment of the present application, the preparation method of the oil-soluble polymer modified molybdenum disulfide nanosheet comprises:

[0014] S1, water phase preparation: after mixing the molybdenum disulfide powder with water, ultrasonic exfoliation is performed to obtain a water phase;

[0015] S2, oil phase preparation: the polymer monomer, the oil-soluble emulsifier and the oily solvent are mixed to obtain an oil phase;

[0016] S3, emulsification: the water phase is added to the oil phase, and stirring is performed to form a uniform and stable emulsion;

[0017] S4, polymerization: under an inert atmosphere, the initiator is added to the emulsion, and heating is performed to react;

[0018] Preferably, the ultrasonic time is 20-30 min, and the ultrasonic frequency is 40 KHZ.

[0019] Preferably, the mass ratio of the molybdenum disulfide powder to the polymer monomer is 1:100-400.

[0020] Preferably, the oil-soluble emulsifier is selected from one or more than two combinations of dodecyl phenol polyoxyethylene ether, sorbitan monostearate, sorbitan monopalmitate and polysorbate 60; preferably, the amount of the oil-soluble emulsifier is 5-10% of the total volume of the emulsion raw materials.

[0021] Preferably, the oily solvent comprises toluene.

[0022] Preferably, the initiator comprises azobisisobutyronitrile; preferably, the amount of the initiator is 0.6-1% of the mass of the polymer monomer.

[0023] Preferably, the reaction temperature is 50-90°C, and the reaction time is 4-8 h.

[0024] As a specific embodiment of the present application, the size of the black phosphorus nanosheet is 50-100 nm.

[0025] As a specific embodiment of the present application, the coupling agent is a silane coupling agent, and is selected from any one of γ-aminopropyl triethoxysilane, γ-aminopropyl trimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane.

[0026] In a second aspect of the present application, a preparation method of the aforementioned nanometer black phosphorus thick oil viscosity reducer is provided, which comprises: mixing the oil-soluble polymer modified molybdenum disulfide nanosheet, the black phosphorus nanosheet, the coupling agent and the oily solvent, and stirring to react; preferably, the oily solvent comprises toluene; preferably, the reaction temperature is 30-50°C, and the reaction time is 8-12 h; preferably, the method further comprises washing and drying the reaction product.

[0027] In a third aspect, the application provides application of the aforementioned nano black phosphorus thick oil viscosity reducer in thick oil viscosity reduction.

[0028] In a fourth aspect, the application provides a thick oil viscosity reduction method, which comprises mixing thick oil and the aforementioned nano black phosphorus thick oil viscosity reducer; preferably, the amount of the nano black phosphorus thick oil viscosity reducer is 300-800 ppm based on the total weight of the mixed raw materials.

[0029] For thick oil with high asphaltene content, the viscosity of the thick oil is mainly caused by the high asphaltene content, the association between asphaltene and resin components, the aggregation of heavy components in the thick oil, and the increase in the viscosity of the thick oil. In addition, in addition to the high content of carbon and hydrogen elements, nickel, vanadium and other metal elements also exist in large amounts in the thick oil. These metal elements act as physical crosslinking points, which can strengthen the interaction between asphaltene and resin, increase the difficulty of thick oil viscosity reduction, and further put high requirements on the thick oil mining and processing technology. The present application combines black phosphorus nanosheets and oil-soluble polymer modified molybdenum disulfide nanosheets, which can disperse the dispersion of heavy components on one hand, and can destroy the physical crosslinking points between asphaltene and resin on the other hand, thereby further reducing the viscosity of the thick oil. Specifically, the improvement of the existing oil-soluble viscosity reducer is focused on increasing the polar functional groups of the oil-soluble polymer, thereby increasing the interaction between the oil-soluble polymer and the asphaltene. These polar groups are mainly amino groups and carboxyl groups. However, the interaction between the polar functional groups and the asphaltene is weak, and the interaction can only be enhanced by increasing the number of polar functional groups. Unlike the prior art, the present application introduces black phosphorus nanosheets as strong polar groups, which have high activity, strong interaction, good temperature resistance and salt resistance. The black phosphorus nanosheets not only can destroy the crosslinking points between asphaltene and resin, but also can greatly increase the interaction between the viscosity reducer and the heavy components, thereby dispersing the asphaltene and resin efficiently and achieving the purpose of reducing the viscosity of the thick oil.

[0030] The present application has the following advantages:

[0031] The preparation raw materials of the nano black phosphorus thick oil viscosity reducer of the present application include oil-soluble polymer modified molybdenum disulfide nanosheet, black phosphorus nanosheet and coupling agent, wherein: 1) compared with unmodified molybdenum disulfide nanosheet, the oil wettability of the oil-soluble polymer modified molybdenum disulfide nanosheet is enhanced, and the oil-soluble polymer modified molybdenum disulfide nanosheet can be better dispersed in thick oil. The molybdenum disulfide nanosheet is the core of the oil-soluble polymer, and the modified structure of the molybdenum disulfide nanosheet is similar to a comb, with the molybdenum disulfide nanosheet as the back of the comb and the polymer as the teeth of the comb. The structure is conducive to the stretching of the polymer and the stretching of the polar functional groups. Compared with the random coil polymer form in the prior art, the structure has stronger interaction with asphaltene and colloid. Since the polymer is grafted and copolymerized on the surface of the molybdenum disulfide nanosheet, the temperature resistance and salt resistance of the overall structure are further improved, and the adaptability to the oil reservoir is enhanced. 2) There is a supramolecular interaction between the black phosphorus nanosheet and metal ions, which can adsorb metal ions in thick oil on the surface, passivate the lone pair electrons of phosphorus atoms in black phosphorus, greatly improve the stability of the black phosphorus sheet layer, and at the same time destroy the crosslinking points between asphaltene and colloid, thereby reducing the viscosity of crude oil. 3) The coupling agent serves to connect the oil-soluble polymer modified molybdenum disulfide nanosheet and the black phosphorus nanosheet. When the coupling agent is a silane coupling agent, the silicon-oxygen bond in the silane coupling agent is connected to the surface of the molybdenum disulfide nanosheet, and the amino group in the silane coupling agent is connected to the surface of the black phosphorus, so that the two nanosheets are combined together through covalent bond, and then the whole interacts with thick oil, which has stronger stability than the general van der Waals force combination mode and is not prone to chromatographic column separation in the reservoir flow process. The present application can prepare a thick oil viscosity reducer with high viscosity reduction rate of 93.64%, good temperature resistance and salt resistance, good compatibility with crude oil and low aggregation by compounding the above raw materials and performing suitable weight ratio. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0033] Unless otherwise specified, the raw materials and reagents in the following embodiments are all ordinary commercially available products, and the purity is all analytical pure.

[0034] Embodiment 1

[0035] The present embodiment provides a nano black phosphorus thick oil viscosity reducer, and the preparation method is as follows:

[0036] (1) 1 g of 1T crystal form molybdenum disulfide powder (100 nm) was ultrasonically dispersed in 30 mL of water, the ultrasonic frequency was 40 KHZ, and the ultrasonic time was 20 min; 80.2 g of methacrylate eicosyl ester, 13.61 g of styrene, 6.19 g of acrylamide, 9.9 g of OP-10 and 6.6 g of Tween 60 were added to 300 mL of toluene. Then 30 mL of molybdenum disulfide aqueous solution was slowly dropped into the toluene solution, and a uniform and stable emulsion was formed by stirring; after nitrogen was introduced, 1 g of azobisisobutyronitrile was added into the emulsion, and the reaction was carried out at 90°C for 5 h; after the reaction was completed, the product was washed with methanol to obtain a single-sided oil-soluble polymer modified molybdenum disulfide nanosheet;

[0037] (2) 1 g of single-sided oil-soluble polymer modified molybdenum disulfide nanosheet, 2 g of black phosphorus nanosheet (50 nm) and 3 g of γ-aminopropyl triethoxysilane were dissolved in 100 mL of toluene, and stirred at 50°C for 8 h; after the reaction was completed, the product was washed with methanol, and after drying at 80°C, a nano black phosphorus thick oil viscosity reducer was obtained.

[0038] Example 2

[0039] The present embodiment provides a nano black phosphorus thick oil viscosity reducer, and the preparation method is as follows:

[0040] (1) 1 g of 1T crystal form molybdenum disulfide powder (200 nm) was ultrasonically dispersed in 30 mL of water, the ultrasonic frequency was 40 KHZ, and the ultrasonic time was 30 min; 316.49 g of methacrylate docosyl ester, 49.94 g of styrene, 33.57 g of acrylamide, 10 g of OP-10 and 20 g of Span 60 were added to 470 mL of toluene. Then 30 mL of molybdenum disulfide aqueous solution was slowly dropped into the toluene solution, and a uniform and stable emulsion was formed by stirring; after nitrogen was introduced, 3.2 g of azobisisobutyronitrile was added into the emulsion, and the reaction was carried out at 90°C for 8 h; after the reaction was completed, the product was washed with methanol to obtain a single-sided oil-soluble polymer modified molybdenum disulfide nanosheet;

[0041] (2) 5 g of single-sided oil-soluble polymer modified molybdenum disulfide nanosheet, 10 g of black phosphorus nanosheet (80 nm) and 25 g of γ-aminopropyl trimethoxysilane were dissolved in 300 mL of toluene, and stirred at 30°C for 12 h; after the reaction was completed, the product was washed with methanol, and after drying at 80°C, a nano black phosphorus thick oil viscosity reducer was obtained.

[0042] Example 3

[0043] The present embodiment provides a nano black phosphorus thick oil viscosity reducer, and the preparation method is as follows:

[0044] (1) 0.5 g of 1T crystal form molybdenum disulfide powder (150 nm) was ultrasonically dispersed in 20 mL of water, the ultrasonic frequency was 40 KHZ, and the ultrasonic time was 20 min; 82.33 g of methyl tetradecyl acrylate, 17.67 g of divinylbenzene, 9 g of OP-10 and 9 g of Span 40 were added to 280 mL of toluene. Then 20 mL of molybdenum disulfide aqueous solution was slowly dropped into the toluene solution, and a uniform and stable emulsion was formed by stirring; after nitrogen was introduced, 0.8 g of azobisisobutyronitrile was added into the emulsion, and the reaction was carried out at 90°C for 8 h; after the reaction was completed, the product was washed with methanol to obtain a single-sided oil-soluble polymer modified molybdenum disulfide nanosheet;

[0045] (2) 1 g of single-sided oil-soluble polymer modified molybdenum disulfide nanosheet, 2 g of black phosphorus nanosheet (50 nm) and 2 g of γ-aminopropyltrimethoxysilane were dissolved in 100 mL of toluene, and stirred at 40°C for 10 h; after the reaction was completed, the product was washed with methanol, and after drying at 80°C, a nano black phosphorus thick oil viscosity reducer was obtained.

[0046] Example 4

[0047] The present embodiment provides a nano black phosphorus thick oil viscosity reducer, and the preparation method is as follows:

[0048] (1) 1 g of 1T crystal form molybdenum disulfide powder (100 nm) was ultrasonically dispersed in 20 mL of water, the ultrasonic frequency was 40 KHZ, and the ultrasonic time was 30 min; 42.02 g of methyl tetradecyl acrylate, 48.39 g of methyl tetradecyl acrylate, 7.14 g of styrene, 2.45 g of acrylamide, 9 g of OP-10 and 9 g of Span 40 were added to 280 mL of toluene. Then 20 mL of molybdenum disulfide aqueous solution was slowly dropped into the toluene solution, and a uniform and stable emulsion was formed by stirring; after nitrogen was introduced, 0.6 g of azobisisobutyronitrile was added into the emulsion, and the reaction was carried out at 60°C for 8 h; after the reaction was completed, the product was washed with methanol to obtain a single-sided oil-soluble polymer modified molybdenum disulfide nanosheet;

[0049] (2) 1 g of single-sided oil-soluble polymer modified molybdenum disulfide nanosheet, 2 g of black phosphorus nanosheet (50 nm) and 6 g of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane were dissolved in 100 mL of toluene, and stirred at 40°C for 6 h; after the reaction was completed, the product was washed with methanol, and after drying at 80°C, a nano black phosphorus thick oil viscosity reducer was obtained.

[0050] Comparative Example 1

[0051] (1) 80.2 g of eicosyl methacrylate, 13.61 g of styrene and 6.19 g of acrylamide were added to 300 mL of toluene. After nitrogen was introduced, 1 g of azobisisobutyronitrile was added, and the reaction was carried out at 90°C for 5 h. After the reaction was completed, the product was washed with methanol to obtain an oil-soluble thick oil viscosity reducer;

[0052] (2) 1 g of the oil-soluble thick oil viscosity reducer, 2 g of black phosphorus nanosheets (50 nm) and 3 g of γ-aminopropyl triethoxysilane were dissolved in 100 mL of toluene, and stirred at 50°C for 8 h. After the reaction was completed, the product was washed with methanol, and dried at 80°C to obtain a nano black phosphorus thick oil viscosity reducer.

[0053] Comparative Example 2

[0054] (1) 1 g of 1T crystal form molybdenum disulfide powder (100 nm) was ultrasonically dispersed in 30 mL of water at an ultrasonic frequency of 40 KHZ for 20 min. 80.2 g of eicosyl methacrylate, 13.61 g of styrene, 6.19 g of acrylamide, 9.9 g of OP-10 and 6.6 g of Tween 60 were added to 300 mL of toluene. Then, 30 mL of the molybdenum disulfide aqueous solution was slowly dropped into the toluene solution to form a uniform and stable emulsion. After nitrogen was introduced, 1 g of azobisisobutyronitrile was added to the emulsion, and the reaction was carried out at 90°C for 5 h. After the reaction was completed, the product was washed with methanol to obtain a single-sided oil-soluble polymer modified molybdenum disulfide nanosheet;

[0055] (2) 1 g of the single-sided oil-soluble polymer modified molybdenum disulfide nanosheet and 3 g of γ-aminopropyl triethoxysilane were dissolved in 100 mL of toluene, and stirred at 50°C for 8 h. After the reaction was completed, the product was washed with methanol, and dried at 80°C to obtain a nano black phosphorus thick oil viscosity reducer.

[0056] Experimental Example

[0057] In this experimental example, the nano black phosphorus thick oil viscosity reducers obtained in Examples 1-4 and Comparative Examples 1-2 were evaluated for viscosity reduction rate, including the following steps:

[0058] (1) Measurement of thick oil viscosity. The thick oil sample must be uniformly preheated before measurement. After preheating at 80°C and continuously stirring for 1 h, it was cooled to 50°C, and the viscosity of the thick oil was measured with a digital viscometer to eliminate experimental errors caused by local non-uniformity or differences in physical properties of the thick oil.

[0059] (2) Viscosity reduction rate evaluation. A certain amount of thick oil at room temperature is heated to 50 DEG C, then the oil-soluble viscosity reducer is dissolved in 3 mL of toluene, and then added into 100 mL of thick oil, and stirred every 20 min with a glass rod and constant temperature for 2 h to make the thick oil and the viscosity reducer fully act. The viscosity of the thick oil after adding the viscosity reducer is measured with a digital viscometer, and the viscosity reduction rate is calculated according to the formula:

[0060]

[0061] In the formula, W is the viscosity reduction rate of thick oil, %; η0 is the original viscosity of thick oil, mPa s; η is the viscosity of thick oil after adding the viscosity reducer, mPa s.

[0062] The experimental results are as follows:

[0063] Table 1

[0064] Group Viscosity reduction rate / % Example 1 90.64 Example 2 88.34 Example 3 85.33 Example 4 93.64 Comparative Example 1 62.31 Comparative Example 2 75.97

[0065] As can be seen from Table 1, the viscosity reduction rate of the nano black phosphorus thick oil viscosity reducer of the present application is high, generally more than 85%. With the increase of the types of polymer monomers, the viscosity reduction rate of the nano black phosphorus thick oil viscosity reducer is further improved, and the polymer in Example 4 is a quaternary copolymer, and the effect is the best, which can reach 93%. Comparative Example 1 does not add molybdenum disulfide nanosheets, and the viscosity reducer obtained is black phosphorus dispersed in an oil-soluble viscosity reducer. Black phosphorus is hydrophilic, and the dispersion effect in crude oil and oil-soluble polymers is poor, and it is easy to aggregate into a group, so the viscosity reduction effect is poor. Comparative Example 2 does not add black phosphorus nanomaterials, and only the oil-soluble polymer modified molybdenum disulfide nanosheets work, and since the polar functional groups have weak interaction with asphaltene, the viscosity reduction effect is also worse than that of the nano black phosphorus thick oil viscosity reducer.

[0066] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

Claims

1. A nanoscale black phosphorus viscous oil viscosity reducer characterized by, The preparation raw materials include: oil-soluble polymer modified molybdenum disulfide nanosheets, black phosphorus nanosheets and coupling agents, and the mass ratio of the oil-soluble polymer modified molybdenum disulfide nanosheets, the black phosphorus nanosheets and the coupling agents is 1:2:2~6; The oil-soluble polymer modified molybdenum disulfide nanosheets have a continuous phase containing an oil-soluble polymer and a dispersed phase containing molybdenum disulfide nanosheets dispersed in the continuous phase; The polymer monomer of the oil-soluble polymer forming the continuous phase is selected from two or more combinations of acrylamide, styrene, divinylbenzene, eicosyl methacrylate, docosyl methacrylate and tetracosyl methacrylate; The preparation method of the oil-soluble polymer modified molybdenum disulfide nanosheets comprises: S1. Water phase preparation: after mixing molybdenum disulfide powder with water, ultrasonic stripping is performed to obtain a water phase; S2. Oil phase preparation: polymer monomers, oil-soluble emulsifiers and oily solvents are mixed to obtain an oil phase; S3. Emulsification: the water phase is added to the oil phase, and stirring is performed to form a uniform and stable emulsion; S4. Polymerization: under an inert atmosphere, an initiator is added to the emulsion, and heating is performed to react; The mass ratio of the molybdenum disulfide powder to the polymer monomer is 1:100~400; The preparation method of the nanometer black phosphorus thick oil viscosity reducer comprises: The oil-soluble polymer modified molybdenum disulfide nanosheets, the black phosphorus nanosheets, the coupling agents and the oily solvents are mixed, and stirring is performed to react; The coupling agent is selected from any one of γ-aminopropyl triethoxysilane, γ-aminopropyl trimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane.

2. The nanoscale black phosphorus viscous oil viscosity reducer of claim 1, wherein, The polymer monomer of the oil-soluble polymer forming the continuous phase is a combination of acrylamide, styrene, eicosyl methacrylate and tetracosyl methacrylate.

3. The nanoscale black phosphorus viscous oil viscosity reducer of claim 2, wherein, The mass ratio of the acrylamide, the styrene, the eicosyl methacrylate and the tetracosyl methacrylate is 2~3:7~8:42~43:48~49.

4. The nano black phosphorus thick oil viscosity reducer according to any one of claims 1 to 3, characterized in that: The molybdenum disulfide nanosheets forming the dispersed phase are selected from molybdenum disulfide nanosheets with a crystal form of 1T, and the size of the molybdenum disulfide nanosheets is 100~200 nm.

5. The nanoscale black phosphorus viscous oil viscosity reducer according to any one of claims 1 to 3, characterized in that, The time of the ultrasonic is 20~30 mn, and the frequency of the ultrasonic is 40 KHZ; The oil-soluble emulsifier is selected from one or more combinations of two or more of dodecyl phenol polyoxyethylene ether, sorbitan monostearate, sorbitan monopalmitate and polysorbate 60; The amount of the oil-soluble emulsifier is 5~10% of the total volume of the emulsion raw materials; The oily solvent includes toluene; The initiator includes azobisisobutyronitrile; The amount of the initiator is 0.6~1% of the mass of the polymer monomer; The temperature of the reaction is 50~90 ℃, and the time of the reaction is 4~8 h.

6. The nanoscale black phosphorus viscous oil viscosity reducer of claim 1, wherein, The size of the black phosphorus nanosheets is 50~100 nm.

7. A method for preparing the nanoscale black phosphorus viscous oil viscosity reducer according to any one of claims 1 to 6, characterized in that, The preparation method comprises: The oil-soluble polymer modified molybdenum disulfide nanosheets, the black phosphorus nanosheets, the coupling agents and the oily solvents are mixed, and stirring is performed to react; The oily solvent includes toluene; The temperature of the reaction is 30~50 ℃, and the time of the reaction is 8~12 h; The reaction product is also washed and dried.

8. The application of the nano black phosphorus thickened oil viscosity reducer of any one of claims 1-6 in thickened oil viscosity reduction.

9. A method of reducing the viscosity of a heavy oil, characterized by, The method comprises mixing thickened oil and the nano black phosphorus thickened oil viscosity reducer of any one of claims 1-6; the amount of the nano black phosphorus thickened oil viscosity reducer is 300-800 ppm based on the total weight of the mixed raw materials.

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