Binary / ternary eutectic solvent viscosity reducer as well as preparation method and application thereof

Abstract

The invention provides a binary / ternary eutectic solvent viscosity reducer as well as a preparation method and application thereof, and belongs to the technical field of crude oil extraction, gathering and transportation. The binary eutectic solvent mixture provided by the invention comprises the formation water, and the metal chlorate in the formation water can enhance the viscosity reduction capacity of the glycerol-choline chloride eutectic solvent; the ternary eutectic solvent comprises aluminum chloride hexahydrate, aluminum ions and chloride ions are provided to form a synergistic coordination effect with hydroxyl of glycerol, and the hydrogen bond acceptance of the ternary eutectic solvent is remarkably enhanced, so that a hydrogen bond network structure in the heavy oil can be effectively competed and damaged, and the intermolecular force of the heavy oil is weakened; by introducing the pure eutectic solvent, the molecular structure of the thick oil can become looser, the interlocking structure of asphaltene can be easily damaged, meanwhile, the eutectic solvent and the metal chlorate or aluminum chloride hexahydrate in the formation water can self-emulsify the thick oil, the viscosity of the extra-thick oil can be reduced, and therefore the effect of remarkably reducing the viscosity of the extra-thick oil from the molecular level is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of crude oil exploitation and gathering and transportation, and specifically relates to a binary / ternary low eutectic solvent viscosity reducer and a preparation method and application thereof. Background Art

[0002] As a key material on which the world's industry depends for survival, the use of oil is one of the pillar energy sources for the rapid development of the entire world economy and has penetrated into all aspects of human social life. With the growth of the global economy, the exploitation of oil resources has become more and more complete, and the recoverable output of conventional crude oil has gradually decreased, resulting in an increase in the proportion of heavy oil resources. Heavy oil generally refers to oil with a viscosity greater than 50mPa·s under geological conditions, or a viscosity greater than 100mPa·s at reservoir temperature and a density greater than 0.92g / cm 3 degassed crude oil. At present, the focus of oil development and utilization has gradually shifted to heavy oil resources. In view of the fact that the main characteristics of heavy oil are high viscosity, high density and poor fluidity, the first task to achieve smooth exploitation and collection of heavy oil is to reduce the viscosity of heavy oil and improve its fluidity. In view of the composition and properties of heavy oil, a variety of heavy oil viscosity reduction mining technologies have been developed. At present, the heavy oil mining technologies at home and abroad mainly include conventional heating viscosity reduction mining technology, physical viscosity reduction mining technology, chemical viscosity reduction mining technology and biological viscosity reduction mining technology. These major technologies have different working principles and their own technical advantages, but they also have some application problems. In recent years, green chemistry and circular economy have become new areas of development advocated, which has brought unprecedented development opportunities for heavy oil development. Among them, the application of ionic liquids (ILs) in heavy oil catalytic upgrading has been widely studied, but the cost of ionic liquids is relatively high, and the preparation is relatively complicated, and it still remains at the laboratory research scale. In addition, the synthesis of ionic liquids requires multi-step chemical reactions, which will cause the generation of waste and serious waste of resources during the synthesis process; in addition, ionic liquids are relatively stable in nature, and ionic liquids released into the environment are difficult to be biodegraded and will also cause environmental pollution. Therefore, there is an urgent need for a product that can reduce the viscosity of heavy oil with low cost and no pollution to the environment. Summary of the invention

[0003] The object of the present invention is to provide a binary / ternary deep eutectic solvent viscosity reducer and a preparation method and application thereof. The binary / ternary deep eutectic solvent viscosity reducer provided by the present invention can effectively reduce the viscosity of heavy oil without causing pollution to the environment.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a binary / ternary low eutectic solvent viscosity reducer, comprising a binary low eutectic solvent mixture or a ternary low eutectic solvent; the binary low eutectic solvent mixture comprises a glycerol-choline chloride low eutectic solvent and formation water; the molar ratio of glycerol to choline chloride in the glycerol-choline chloride low eutectic solvent is (1-3):1; the ternary low eutectic solvent comprises a glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent; the molar ratio of glycerol, choline chloride and aluminum chloride hexahydrate in the glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent is (1-3):1:(0.01-0.5).

[0006] Preferably, the mass concentration of the glycerol-choline chloride deep eutectic solvent in the binary deep eutectic solvent mixture is 3-50%.

[0007] Preferably, the ternary deep eutectic solvent also includes pure water or formation water.

[0008] Preferably, the mass concentration of the glycerol-choline chloride-aluminum chloride hexahydrate deep eutectic solvent in the ternary deep eutectic solvent is 50-99%.

[0009] The present invention also provides a method for preparing a binary deep eutectic solvent mixture in the binary / ternary deep eutectic solvent viscosity reducer described in the above technical solution, comprising the following steps:

[0010] (1) mixing glycerol and choline chloride to obtain a glycerol-choline chloride deep eutectic solvent;

[0011] (2) Mixing the glycerol-choline chloride low eutectic solvent obtained in step (1) with formation water to obtain a binary low eutectic solvent mixture.

[0012] Preferably, the mixing temperature in step (1) is 75-85°C.

[0013] The present invention also provides a method for preparing a ternary low eutectic solvent in the binary / ternary low eutectic solvent viscosity reducer described in the above technical solution, comprising: mixing glycerol, choline chloride and aluminum chloride hexahydrate to obtain a ternary low eutectic solvent.

[0014] Preferably, the mixing temperature is 95-105°C.

[0015] The present invention also provides the use of the binary / ternary low eutectic solvent viscosity reducer described in the above technical solution or the binary / ternary low eutectic solvent viscosity reducer prepared according to the preparation method described in the above technical solution in reducing the viscosity of heavy oil.

[0016] Preferably, the mass ratio of the binary / ternary low eutectic solvent viscosity reducer to the heavy oil is (25-35):(65-75).

[0017] The present invention provides a binary / ternary low eutectic solvent viscosity reducer, comprising a binary low eutectic solvent mixture or a ternary low eutectic solvent; the binary low eutectic solvent mixture comprises a glycerol-choline chloride low eutectic solvent and formation water; the molar ratio of glycerol to choline chloride in the glycerol-choline chloride low eutectic solvent is (1-3):1; the ternary low eutectic solvent comprises a glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent; the molar ratio of glycerol, choline chloride and aluminum chloride hexahydrate in the glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent is (1-3):1:(0.01-0.5). The binary low eutectic solvent mixture provided by the present invention includes formation water, and the metal chloride in the formation water can emulsify the heavy oil with glycerol-choline chloride to form an oil-in-water emulsion, thereby enhancing the viscosity reducing ability of the glycerol-choline chloride low eutectic solvent; the ternary low eutectic solvent provided by the present invention includes aluminum chloride hexahydrate, which provides aluminum ions and chloride ions, and these ions can form a synergistic coordination effect with the hydroxyl group of glycerol, significantly enhancing the hydrogen bond acceptance ability of the ternary low eutectic solvent, thereby effectively competing and destroying the hydrogen bond network structure in the heavy oil, and weakening the intermolecular force of the heavy oil; the introduction of the pure low eutectic solvent can make the molecular structure of the heavy oil looser, which is helpful to destroy the interlocking structure of asphaltene, resulting in a loose asphalt / colloid structure, and at the same time, the low eutectic solvent and the metal chloride or aluminum chloride hexahydrate in the formation water can self-emulsify the heavy oil to form an oil-in-water emulsion, which can reduce the viscosity of the extra-heavy oil, thereby achieving the effect of significantly reducing the viscosity of the extra-heavy oil at the molecular level. The results of the examples show that after the viscosity reducer provided by the present invention is mixed with heavy oil, the viscosity reduction rate of the heavy oil is above 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is an optical microscope image at a magnification of 200 times after the viscosity reducer prepared in Example 1 is mixed with heavy oil to reduce viscosity;

[0019] Figure 2 This is an optical microscope picture at a magnification of 500 times after the viscosity reducer prepared in Example 1 is mixed with heavy oil to reduce the viscosity. DETAILED DESCRIPTION

[0020] The present invention provides a binary / ternary low eutectic solvent viscosity reducer, comprising a binary low eutectic solvent mixture or a ternary low eutectic solvent; the binary low eutectic solvent mixture comprises a glycerol-choline chloride low eutectic solvent and formation water; the molar ratio of glycerol to choline chloride in the glycerol-choline chloride low eutectic solvent is (1-3):1; the ternary low eutectic solvent comprises a glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent; the molar ratio of glycerol, choline chloride and aluminum chloride hexahydrate in the glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent is (1-3):1:(0.01-0.5).

[0021] As an embodiment, the binary / ternary deep eutectic solvent viscosity reducer provided by the present invention comprises a binary deep eutectic solvent mixture.

[0022] In the present invention, the binary deep eutectic solvent mixture comprises glycerol-choline chloride deep eutectic solvent and formation water.

[0023] In the present invention, the molar ratio of glycerol to choline chloride in the glycerol-choline chloride deep eutectic solvent is (1-3):1, preferably 2:1.

[0024] The present invention has no particular limitation on the source of the formation water, and formation water familiar to those skilled in the art can be used. In the present invention, the formation water contains metal chlorides, such as calcium chloride and magnesium chloride, which can enhance the viscosity reduction effect of the glycerol-choline chloride deep eutectic solvent.

[0025] In the present invention, the mass concentration of the glycerol-choline chloride deep eutectic solvent in the binary deep eutectic solvent mixture is preferably 3 to 50%. In an embodiment of the present invention, the mass concentration of the glycerol-choline chloride deep eutectic solvent in the binary deep eutectic solvent mixture may be specifically 3%, 5%, 10%, 15%, 20%, 25%, 30%, 40% or 50%. The present invention controls the mass concentration of the glycerol-choline chloride deep eutectic solvent in the binary deep eutectic solvent mixture within the above range, which can further improve the viscosity reduction effect of the binary deep eutectic solvent mixture.

[0026] As another embodiment, the binary / ternary low eutectic solvent viscosity reducer provided by the present invention includes a ternary low eutectic solvent.

[0027] In the present invention, the ternary low eutectic solvent includes a glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent. The ternary low eutectic solvent of the present invention includes aluminum chloride hexahydrate, which provides aluminum ions and chloride ions. These ions can form a synergistic coordination effect with the hydroxyl group of glycerol, significantly enhancing the hydrogen bond acceptance capacity of the ternary low eutectic solvent, thereby being able to effectively compete and destroy the hydrogen bond network structure in the heavy oil, and weakening the intermolecular force of the heavy oil; the introduction of the low eutectic solvent may make the molecular structure of the heavy oil looser, which helps to destroy the interlocking structure of asphaltene. As the distance between asphaltene groups increases, the heavy oil structure gradually disperses, resulting in its saturated and aromatic components no longer being tightly wrapped by asphaltene. This dispersed structure is difficult to maintain the original high viscosity of the heavy oil, thereby achieving the effect of significantly reducing the viscosity of the heavy oil at the molecular level.

[0028] In the present invention, the molar ratio of glycerol, choline chloride and aluminum chloride hexahydrate in the glycerol-choline chloride-aluminum chloride hexahydrate deep eutectic solvent is (1-3):1:(0.01-0.5), preferably 2:1:0.1. The present invention controls the molar ratio of glycerol, choline chloride and aluminum chloride hexahydrate within the above range, which can further improve the viscosity reducing effect of the viscosity reducer.

[0029] In the present invention, the ternary deep eutectic solvent preferably further comprises pure water or formation water.

[0030] In the present invention, when the ternary deep eutectic solvent includes pure water or formation water, the mass concentration of the glycerol-choline chloride-aluminum chloride hexahydrate deep eutectic solvent in the ternary deep eutectic solvent is preferably 50 to 99%. The present invention controls the mass concentration of the glycerol-choline chloride-aluminum chloride hexahydrate deep eutectic solvent within the above range, which can further improve the viscosity reducing effect of the viscosity reducer.

[0031] The present invention adopts a low eutectic solvent to reduce the viscosity of heavy oil, which can effectively reduce the viscosity of heavy oil without causing pollution to the environment.

[0032] The present invention also provides a method for preparing a binary deep eutectic solvent mixture in the binary / ternary deep eutectic solvent viscosity reducer described in the above technical solution, comprising the following steps:

[0033] (1) mixing glycerol and choline chloride to obtain a glycerol-choline chloride deep eutectic solvent;

[0034] (2) Mixing the glycerol-choline chloride low eutectic solvent obtained in step (1) with formation water to obtain a binary low eutectic solvent mixture.

[0035] The invention mixes glycerol and choline chloride to obtain a glycerol-choline chloride low eutectic solvent.

[0036] In the present invention, the mixing temperature is preferably 75-85°C, more preferably 80°C; the mixing is preferably carried out under stirring conditions. The present invention has no particular limitation on the stirring method and rate, and the stirring method and rate well known to those skilled in the art can be used. The present invention has no particular limitation on the mixing time, and the mixing time can be sufficient to allow the two to form a homogeneous transparent liquid.

[0037] After obtaining the glycerol-choline chloride deep eutectic solvent, the present invention mixes the glycerol-choline chloride deep eutectic solvent with formation water to obtain a binary deep eutectic solvent mixture.

[0038] The present invention has no special limitation on the mixing operation of the glycerol-choline chloride deep eutectic solvent and the formation water. The two can be evenly mixed using a material mixing technical solution well known to those skilled in the art.

[0039] The present invention also provides a method for preparing a ternary low eutectic solvent in the binary / ternary low eutectic solvent viscosity reducer described in the above technical solution, comprising: mixing glycerol, choline chloride and aluminum chloride hexahydrate to obtain a ternary low eutectic solvent.

[0040] In the present invention, the mixing temperature is preferably 95-105°C, more preferably 100°C; the mixing is preferably carried out under stirring conditions. The present invention has no special restrictions on the stirring method and rate, and the stirring method and rate well known to those skilled in the art can be used. The present invention has no special restrictions on the mixing time, and it can be sufficient to allow the three to form a homogeneous transparent liquid.

[0041] When the ternary deep eutectic solvent includes pure water or formation water, the present invention preferably cools the homogeneous transparent liquid obtained by mixing glycerol, choline chloride and aluminum chloride hexahydrate to room temperature, and then mixes it with pure water or formation water to obtain the ternary deep eutectic solvent.

[0042] The preparation method provided by the invention is simple.

[0043] The present invention also provides the use of the binary / ternary low eutectic solvent viscosity reducer described in the above technical solution or the binary / ternary low eutectic solvent viscosity reducer prepared according to the preparation method described in the above technical solution in reducing the viscosity of heavy oil.

[0044] In the present invention, the mass ratio of the binary / ternary deep eutectic solvent viscosity reducer to the heavy oil is preferably (25-35): (65-75), and more preferably 30: 70. The present invention controls the mass ratio of the viscosity reducer to the heavy oil within the above range, which can further reduce the viscosity of the heavy oil.

[0045] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The preparation method of the formation water in each embodiment is: 5.00 g of sodium chloride, 5.00 g of sodium bicarbonate, 0.13 g of anhydrous sodium carbonate, 0.06 g of anhydrous calcium chloride, 0.067 g of magnesium chloride hexahydrate and 1000 mL of distilled water are mixed to obtain formation water.

[0047] Example 1

[0048] A binary low eutectic solvent viscosity reducer, comprising a glycerol-choline chloride low eutectic solvent and formation water; the molar ratio of glycerol to choline chloride in the glycerol-choline chloride low eutectic solvent is 2:1, and the mass concentration of the glycerol-choline chloride low eutectic solvent in the binary low eutectic solvent mixture is 5%;

[0049] The preparation method of the binary low eutectic solvent viscosity reducer comprises: stirring glycerol and choline chloride at 80° C. to form a homogeneous transparent liquid, cooling to room temperature and mixing with formation water to obtain the binary low eutectic solvent viscosity reducer.

[0050] Example 2

[0051] The mass concentration of the glycerol-choline chloride deep eutectic solvent in the viscosity reducer of Example 1 was replaced with 10%, and the other parameters were the same as those of Example 1.

[0052] Example 3

[0053] The mass concentration of the glycerol-choline chloride deep eutectic solvent in the viscosity reducer of Example 1 was replaced with 25%, and the other parameters were the same as those of Example 1.

[0054] Example 4

[0055] The mass concentration of the glycerol-choline chloride deep eutectic solvent in the viscosity reducer of Example 1 was replaced with 50%, and the other parameters were the same as those of Example 1.

[0056] Comparative Example 1

[0057] Formation water in Example 1.

[0058] Comparative Example 2

[0059] The formation water in Example 1 is omitted, that is, only the glycerol-choline chloride deep eutectic solvent is included.

[0060] Comparative Example 3

[0061] Pure water.

[0062] Comparative Example 4

[0063] The formation water in Example 1 was replaced with pure water, and other parameters were the same as those in Example 1.

[0064] Comparative Example 5

[0065] The formation water in Example 2 was replaced by pure water, and the other parameters were the same as those in Example 2.

[0066] Comparative Example 6

[0067] The formation water in Example 3 was replaced by pure water, and the other parameters were the same as those in Example 3.

[0068] Comparative Example 7

[0069] The formation water in Example 4 was replaced by pure water, and the other parameters were the same as those in Example 4.

[0070] The viscosity reducers or pure water in Comparative Examples 2 to 7 were mixed with heavy oil in a mass ratio of 30:70, and the viscosity reduction rate of the heavy oil was measured using a Brookfield viscometer. The results are shown in Table 1. The test temperature was 50° C., and the viscosity reduction rate was calculated as follows: Wherein: M-viscosity reduction rate, %; η1-viscosity of heavy oil at 50°C, unit: mPa·s; η2-viscosity of heavy oil at 50°C after adding viscosity reducer or pure water, unit: mPa·s.

[0071] Table 1 Viscosity reduction rate of heavy oil by viscosity reducer or pure water in Comparative Examples 2 to 7

[0072]

[0073] In the same manner, the viscosity reduction rates of the viscosity reducers or formation water on the heavy oil in Examples 1 to 4 and Comparative Examples 1 to 2 were tested. The results are shown in Table 2.

[0074] Table 2 Viscosity reduction rate of heavy oil by viscosity reducer or formation water in Examples 1 to 4 and Comparative Examples 1 to 2

[0075]

[0076]

[0077] As can be seen from Tables 1 and 2, at an experimental temperature of 50°C, the binary eutectic solvent system of different concentrations prepared with pure water has a poor effect on reducing the viscosity of heavy oil. When the stirring stops, the oil and water in the mixed system separate almost immediately, indicating that the dispersion and viscosity reduction capabilities of the solvent are insufficient. In contrast, the binary eutectic solvent system of different concentrations prepared with formation water shows a significant effect in reducing viscosity, and the viscosity reduction rate is basically maintained above 99.5%. This phenomenon may be related to the presence of metal chlorides (such as calcium chloride and magnesium chloride hexahydrate) in formation water, which may enhance the viscosity reduction ability of the low eutectic solvent.

[0078] The optical microscope images at different magnifications after the viscosity reducer prepared in Example 1 was mixed with heavy oil to reduce viscosity are as follows: Figure 1 and Figure 2 As shown, Figure 1 The magnification is 200 times. Figure 2 The magnification is 500 times. Figure 1 and Figure 2 It can be seen that the binary low eutectic solvent and heavy oil form an O / W emulsion, and the emulsification and viscosity reduction effect is significant.

[0079] Example 5

[0080] Ternary low eutectic solvent viscosity reducer: glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent, the molar ratio of glycerol, choline chloride and aluminum chloride hexahydrate is 2:1:0.1;

[0081] The preparation method of the viscosity reducer comprises the following steps: stirring glycerol, choline chloride and aluminum chloride hexahydrate at 100° C. to form a homogeneous transparent liquid, and cooling the mixture to room temperature to obtain the viscosity reducer.

[0082] Example 6

[0083] The ternary low eutectic solvent viscosity reducer is composed of a glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent and pure water, wherein the molar ratio of glycerol, choline chloride and aluminum chloride hexahydrate in the glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent is 2:1:0.1; and the mass concentration of the glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent in the viscosity reducer is 50%;

[0084] The preparation method of the viscosity reducer is as follows: glycerol, choline chloride and aluminum chloride hexahydrate are stirred at 100° C. to form a homogeneous transparent liquid, and then the mixture is cooled to room temperature and mixed with pure water to obtain a ternary low eutectic solvent viscosity reducer.

[0085] Comparative Example 8

[0086] The mass concentration of the glycerol-choline chloride-aluminum chloride hexahydrate eutectic solvent in the viscosity reducer of Example 6 was replaced with 5%, and the other parameters were the same as those of Example 6.

[0087] Comparative Example 9

[0088] The mass concentration of the glycerol-choline chloride-aluminum chloride hexahydrate eutectic solvent in the viscosity reducer of Example 6 was replaced with 10%, and the other parameters were the same as those of Example 6.

[0089] Comparative Example 10

[0090] The mass concentration of the glycerol-choline chloride-aluminum chloride hexahydrate eutectic solvent in the viscosity reducer of Example 6 was replaced with 25%, and the other parameters were the same as those of Example 6.

[0091] In the same manner, the viscosity reducing effects of pure water or viscosity reducing agents on heavy oil in Comparative Example 3, Examples 5-6 and Comparative Examples 8-10 were tested. The results are shown in Table 3.

[0092] Table 3 Viscosity reduction effect of pure water or viscosity reducer on heavy oil in Comparative Example 3, Examples 5-6 and Comparative Examples 8-10

[0093]

[0094] It can be seen from Table 3 that the ternary deep eutectic solvent system prepared with pure water has a slightly better effect in reducing viscosity than the binary deep eutectic solvent system. In particular, the glycerol-choline chloride-aluminum chloride hexahydrate deep eutectic solvent in Example 5 has a much better viscosity reducing effect than the glycerol-choline chloride deep eutectic solvent without formation water, showing a significant viscosity reducing advantage.

[0095] In summary, the present invention uses a low eutectic solvent to reduce the viscosity of heavy oil and extra-heavy oil, which has an excellent viscosity reduction effect, and choline chloride / glycerol is biodegradable and will not cause harm to the environment even if released into the environment.

[0096] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A binary / ternary deep eutectic solvent viscosity reducer, comprising a binary deep eutectic solvent mixture or a ternary deep eutectic solvent; the binary deep eutectic solvent mixture comprises a glycerol-choline chloride deep eutectic solvent and formation water; the molar ratio of glycerol to choline chloride in the glycerol-choline chloride deep eutectic solvent is (1-3):1; the ternary deep eutectic solvent comprises a glycerol-choline chloride-aluminum chloride hexahydrate deep eutectic solvent; the molar ratio of glycerol, choline chloride and aluminum chloride hexahydrate in the glycerol-choline chloride-aluminum chloride hexahydrate deep eutectic solvent is (1-3):1:(0.01-0.5).

2. The binary / ternary deep eutectic solvent viscosity reducer according to claim 1, characterized in that: The mass concentration of the glycerol-choline chloride deep eutectic solvent in the binary deep eutectic solvent mixture is 3-50%.

3. The binary / ternary deep eutectic solvent viscosity reducer according to claim 1, characterized in that: The ternary deep eutectic solvent also includes pure water or formation water.

4. The binary / ternary deep eutectic solvent viscosity reducer according to claim 3, characterized in that: The mass concentration of the glycerol-choline chloride-aluminum chloride hexahydrate low eutectic solvent in the ternary low eutectic solvent is 50-99%.

5. The method for preparing a binary deep eutectic solvent mixture in the binary / ternary deep eutectic solvent viscosity reducer according to any one of claims 1 to 4, comprising the following steps: (1) mixing glycerol and choline chloride to obtain a glycerol-choline chloride deep eutectic solvent; (2) Mixing the glycerol-choline chloride low eutectic solvent obtained in step (1) with formation water to obtain a binary low eutectic solvent mixture.

6. The preparation method according to claim 5, characterized in that: The mixing temperature in step (1) is 75-85°C.

7. A method for preparing a ternary deep eutectic solvent in the binary / ternary deep eutectic solvent viscosity reducer according to any one of claims 1 to 4, comprising: Glycerol, choline chloride and aluminum chloride hexahydrate are mixed to obtain a ternary deep eutectic solvent.

8. The preparation method according to claim 7, characterized in that: The mixing temperature is 95-105°C.

9. Use of the binary / ternary deep eutectic solvent viscosity reducer according to any one of claims 1 to 4 or the binary / ternary deep eutectic solvent viscosity reducer prepared by the preparation method according to any one of claims 5 to 8 in reducing the viscosity of heavy oil.

10. The use according to claim 9, characterized in that: The mass ratio of the binary / ternary low eutectic solvent viscosity reducer to the heavy oil is (25-35): (65-75).

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