Thickened oil emulsifying viscosity reducer composition and application thereof

Abstract

The invention discloses a thick oil emulsifying viscosity reducer composition which comprises alkyl amide propyl hydroxy sulfobetaine, a quaternary ammonium salt compound containing tertiary amine and hydroxyl and water, and the content of the alkyl amide propyl hydroxy sulfobetaine is 10%-40%, preferably 25%-30%, the content of the quaternary ammonium salt compound containing tertiary amine and hydroxyl is 10%-40%, preferably 25%-30%, and the content of the quaternary ammonium salt compound containing tertiary amine and hydroxyl is 10%-40%. 3%-15%, preferably 8%-10%, of a quaternary ammonium salt compound containing tertiary amine and hydroxyl. The thick oil emulsifying viscosity reducer with strong foaming performance provided by the invention can emulsify thick oil to form an oil-in-water emulsion, so that the viscosity of the thick oil is obviously reduced, and the fluidity of the thick oil is improved; and the viscosity reducer has good foaming performance and foam stabilizing performance, can effectively block high-permeability pore channels, reduces the water channeling degree, and improves the sweep efficiency of the viscosity reducer, thereby improving the recovery rate of heavy oil.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas field exploitation, and particularly relates to a heavy oil emulsification viscosity reducer composition with strong foaming performance and an application thereof. Background Art

[0002] my country's heavy oil reservoirs are seriously heterogeneous, with a wide variety of types, and most of them are buried at a depth of more than 800m, much higher than foreign oil reservoirs. Due to the intermolecular stacking and hydrogen bond interactions, heavy oil exhibits high viscosity and is difficult to flow, resulting in an excessively high oil-water mobility ratio between the water phase and the heavy oil. Water channeling is prone to occur during water injection development, and the sweep coefficient is reduced. The high viscosity and low mobility of heavy oil also make it easier for it to remain in porous media, making it difficult to displace, resulting in low reservoir recovery and a rapid decline in production capacity. In order to reduce the difficulty of heavy oil extraction, it is necessary to reduce the viscosity of heavy oil, increase the mobility of heavy oil, and improve the oil-water mobility ratio.

[0003] As the development of oil and gas fields enters the middle and late stages, foam flooding, as one of the tertiary oil recovery technologies, has gradually become one of the effective methods to improve oil recovery. Foam has the characteristics of high viscosity. By blocking the high permeability layer and opening the low permeability layer, it can effectively improve the sweep efficiency and increase the oil recovery rate of the reservoir. The addition of viscosity reducer molecules to the foam agent can effectively reduce the viscosity of heavy oil, improve the fluidity of heavy oil, adjust the water-oil mobility ratio, and improve the oil recovery efficiency. On the original basis, it can further improve the oil recovery rate of the reservoir while controlling the economic cost. Therefore, the application of foam flooding to heavy oil reservoirs in order to achieve the dual effects of improving the sweep coefficient and improving the oil recovery efficiency at the same time is of great significance to ensure the efficient development of heavy oil reservoirs.

[0004] For heavy oil reservoirs, reducing the viscosity of heavy oil, improving the oil-water mobility ratio, and increasing the sweep efficiency are key technologies and ways to significantly improve the development effect of heavy oil. On the premise of ensuring that the chemical agent has good emulsification and viscosity reduction performance, starting from the foaming performance, we develop heavy oil emulsification and viscosity reduction agents with strong foaming performance, and study the application of heavy oil plugging, viscosity reduction and oil displacement integrated technology in heavy oil reservoirs. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a heavy oil emulsified viscosity reducer composition and application thereof.

[0006] The invention provides a heavy oil emulsified viscosity reducer composition, which comprises alkyl amidopropyl hydroxysulfonate betaine, a quaternary ammonium salt compound containing a tertiary amine and a hydroxyl group, and water. Based on the total mass of the composition being 100%, the content of the alkyl amidopropyl hydroxysulfonate betaine is 10%-40%, preferably 25%-30%; the content of the quaternary ammonium salt compound containing a tertiary amine and a hydroxyl group is 3%-15%, preferably 8%-10%.

[0007] According to one embodiment of the present invention, the structure of the alkylamidopropyl hydroxysulfonate betaine is as follows

[0008] As shown in formula 1:

[0009]

[0010] Among them, R is from C6 to C 24 Any of the alkyl and alkenyl groups, preferably C8 to C 20 Alkyl, most preferably C 10 ~C 16 of normal alkyl.

[0011] According to another embodiment of the present invention, the structure of the quaternary ammonium salt compound containing a tertiary amine and a hydroxyl group is shown in Formula 2:

[0012]

[0013] Wherein the group R1 is C 4-28 Any of alkyl and alkenyl, preferably C 12-18 normal alkyl; R2 and R3 are each independently selected from CH3, C2H5, 1C3H7 or C4H9, preferably C2H5; X is Cl or Br.

[0014] According to another embodiment of the present invention, the composition further comprises a foam stabilizer and / or a co-surfactant, wherein the content of the foam stabilizer accounts for 0-10% of the total mass of the heavy oil emulsified viscosity reducer, preferably 4%-6%; the content of the co-surfactant accounts for 0%-6% of the total mass of the heavy oil emulsified viscosity reducer, preferably 3%-5%.

[0015] According to another embodiment of the present invention, the foam stabilizer is fatty acid diethanolamide represented by formula 3:

[0016]

[0017] Among them, R4 is composed of C8-C 20 Saturated fatty acids, C8-C 20 Vegetable oil fatty acids or C8-C 20 Preferably, the C8-C 20 The vegetable oil fatty acid is provided by at least one of coconut oleic acid, cotton oleic acid and tall oil acid. 12 -C 18 Normal saturated fatty acids or C 12 -C 18 Provided by normal vegetable oil fatty acids.

[0018] According to another embodiment of the present invention, the co-surfactant is an alcohol having 2 to 14 carbon atoms, preferably one or more of n-heptanol, n-octanol, and dodecanol.

[0019] The present invention also provides an application of the heavy oil emulsified viscosity reducer composition in single-well huff-and-puff production of heavy oil reservoirs.

[0020] According to one embodiment of the present invention, the heavy oil emulsified viscosity reducer composition is combined with N2 and / or CO2 throughput.

[0021] According to another embodiment of the present invention, a certain mass fraction of the heavy oil emulsified viscosity reducer composition is injected into the oil well, preferably the mass fraction is 0.3%-5%, more preferably the mass fraction is 1%-3%, and then a high-pressure N2 or / and CO2 plug is injected into the oil well, and then the well is shut down.

[0022] The present invention further provides an application of a heavy oil emulsified viscosity reducer composition in chemical flooding of heavy oil reservoirs.

[0023] According to one embodiment of the present invention, a certain mass fraction of the heavy oil emulsified viscosity reducer composition is first pulse-injected into the injection well, preferably with a mass fraction of 0.1%-3%, more preferably with a mass fraction of 0.3%-1.5%, and then N2 and / or CO2 plugs are injected into the injection well, followed by water injection.

[0024] According to another embodiment of the present invention, the heavy oil emulsified viscosity reducer composition and N2 or CO2 are alternately injected into several slugs.

[0025] According to another embodiment of the present invention, the heavy oil emulsified viscosity reducer composition and N2 or CO2 plug are simultaneously injected into the injection well, preferably the mass fraction of the viscosity reducer is 0.1%-3%, more preferably the mass fraction is 0.3%-1.5%.

[0026] According to another embodiment of the present invention, after the crossflow channel is blocked by the foam, the injection of the N2 or CO2 plug is stopped and the injection of the viscosity reducer solution is continued.

[0027] Compared with the prior art, the thick oil emulsified viscosity reducer composition of the present invention has the following advantages:

[0028] (1) The viscosity reducer composition of the present invention and gas can quickly form a stable foam system, adjust the water-oil mobility ratio, prevent water channeling, expand the affected area, and improve the development effect. The generation of a large amount of foam in the formation can increase the elasticity and improve the oil recovery efficiency.

[0029] (2) The viscosity reducer composition of the present invention can rapidly form an oil-in-water emulsion under low shearing action, thereby significantly reducing the viscosity of heavy oil and improving the fluidity of heavy oil.

[0030] (3) The viscosity reducer composition of the present invention can reduce the oil-water interfacial tension, improve the wettability of the pore wall, reduce the adhesion work of heavy oil on the pore wall, and improve the oil washing efficiency.

[0031] (4) The co-surfactant in the viscosity reducer composition of the present invention can be adsorbed on the gas-liquid surface to stabilize the foam, and can also penetrate into the interior of the heavy oil to weaken the hydrogen bonding between the asphaltene colloid aggregates, partially destroy the aggregate structure, reduce the viscosity of the heavy oil, and improve the fluidity of the heavy oil.

[0032] (5) The viscosity reducer composition has the advantages of high temperature resistance and high salt resistance, and can be used in deep heavy oil, edge and bottom water heavy oil, heterogeneous low permeability heavy oil and heavy oil reservoirs with complex formation conditions. DETAILED DESCRIPTION

[0033] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0034] The thick oil emulsified viscosity reducer composition of the invention comprises alkyl amidopropyl hydroxysulfonate betaine, a quaternary ammonium salt compound containing a tertiary amine and a hydroxyl group, and water. Based on the total mass of the composition being 100%, the content of the alkyl amidopropyl hydroxysulfonate betaine is 10%-40%, preferably 25%-30%; the content of the quaternary ammonium salt compound containing a tertiary amine and a hydroxyl group is 3%-15%, preferably 8%-10%.

[0035] In an optional embodiment, the structure of alkylamidopropyl hydroxysulfonate betaine is shown in Formula 1:

[0036]

[0037] Among them, R is from C6 to C 24 Any of the alkyl and alkenyl groups, preferably C8 to C 20 Alkyl, most preferably C 10 ~C 16 of normal alkyl.

[0038] The structure of the quaternary ammonium salt compound containing a tertiary amine and a hydroxyl group is shown in Formula 2:

[0039]

[0040] Wherein the group R1 is C 4-28 Any of alkyl and alkenyl, preferably C 12-18 normal alkyl; R2 and R3 are each independently selected from CH3, C2H5, 1C3H7 or C4H9, preferably C2H5; X is Cl or Br.

[0041] In an optional embodiment, the composition further comprises a foam stabilizer and / or a co-surfactant. The content of the foam stabilizer accounts for 0-10% of the total mass of the heavy oil emulsified viscosity reducer, preferably 4%-6%. The content of the co-surfactant accounts for 0%-6% of the total mass of the heavy oil emulsified viscosity reducer, preferably 3%-5%.

[0042] The foam stabilizer is fatty acid diethanolamide shown in formula 3:

[0043]

[0044] Among them, R4 is composed of C8-C 20 Saturated fatty acids, C8-C 20 Vegetable oil fatty acids or C8-C 20 Preferably, C8-C 20 The vegetable oil fatty acid is provided by at least one of coconut oleic acid, cotton oleic acid and tall oil acid. 12 -C 18 Normal saturated fatty acids or C 12 -C 18 Provided by normal vegetable oil fatty acids.

[0045] The auxiliary surfactant is an alcohol having 2 to 14 carbon atoms, preferably one or more of n-heptanol, n-octanol and dodecanol.

[0046] The heavy oil emulsified viscosity reducer composition of the present invention can be prepared by any appropriate method. For example, but not limited to: adding a certain amount of alkylamidopropyl hydroxysulfonic acid betaine, a quaternary ammonium salt compound containing a tertiary amine and a hydroxyl group, a foam stabilizer, a co-surfactant and water to a reactor, stirring evenly, to obtain a heavy oil emulsified viscosity reducer composition with strong foaming performance. Preferably, the mixing conditions at least meet the following conditions: the temperature is 5-50° C., and the stirring time is 20-60 min.

[0047] The heavy oil emulsified viscosity reducer composition of the present invention can be used in single well huff and puff production of heavy oil reservoirs. The heavy oil emulsified viscosity reducer composition is combined with N2 or / and CO2 huff and puff. First, a certain mass fraction of the viscosity reducer composition is injected into the oil well, preferably the mass fraction of the heavy oil emulsified viscosity reducer composition is 0.3%-5%, more preferably the mass fraction is 1%-3%, then a high-pressure N2 or CO2 segment plug is injected into the oil well, and then the well is shut down. The mass fraction of the heavy oil emulsified viscosity reducer composition referred to in the application refers to the mass percentage of the heavy oil emulsified viscosity reducer composition as a substance in water, which has the same meaning hereinafter. The strong foaming property of the viscosity reducer forms a foam system when it contacts with N2 or CO2 gas, blocks the high permeability pores, and improves the sweep coefficient of the viscosity reducer. The injected viscosity reducer forms an oil-in-water emulsion with the heavy oil, greatly reduces the viscosity of the heavy oil, reduces the flow resistance of the crude oil, and thus improves the recovery rate of the reservoir.

[0048] Two application methods of the heavy oil emulsified viscosity reducer composition of the present invention in chemical flooding of heavy oil reservoirs.

[0049] The first application method is to first pulse-inject a certain mass fraction of the viscosity reducer solution into the injection well, preferably the mass fraction of the viscosity reducer is 0.1%-3%, and more preferably the mass fraction is 0.3%-1.5%, and then inject N2 or CO2 plugs into the injection well. The viscosity reducer solution and N2 or CO2 can be alternately injected into several plugs, and then water injection is used for displacement.

[0050] The second application method: inject the viscosity reducer solution and N2 or CO2 into the injection well at the same time, preferably the mass fraction of the viscosity reducer is 0.1%-3%, and more preferably the mass fraction is 0.3%-1.5%. Preferably, the second application method also includes the following steps: after the foam blocks the crossflow channel, stop injecting N2 or CO2, and continue to inject the viscosity reducer solution, so that after the crossflow channel is blocked, the viscosity reducer solution can enter the non-crossflow channel, and use its emulsification and viscosity reduction function to improve fluidity. The above steps are repeated until the development is completed. The purpose is to fully foam the viscosity reducer solution and N2 or CO2 in the formation, circulate the plugging and adjusting effect of the foam and the viscosity reduction effect of the viscosity reducer on the heavy oil, and improve the development effect of the heavy oil reservoir.

[0051] The inventive concept of the present invention is explained in detail below with reference to the examples. In the following examples, unless otherwise specified, all reagents used are commercially available chemical reagents, and there is no particular limitation to this.

[0052] Some of the raw materials used in the preparation examples, embodiments and comparative examples are shown in Table 1:

[0053] Table 1

[0054] Product Name factory purity Laurylamidopropyl Hydroxysulfobetaine Guangdong Wengjiang Chemical Reagent Co., Ltd. >95％ Cocamidopropyl Hydroxysultaine Guangdong Wengjiang Chemical Reagent Co., Ltd. >95％ Lauric acid diethanolamide Inokay >99％ Coconut oil diethanolamide Hubei Xinrunde Chemical Co., Ltd. >95％ Octanol Inokay >99％ Dodecanol Inokay >99％ Diethylamine Inokay >99％ Dodecyl dimethyl tertiary amine Inokay >95％ Hexadecyl dimethyl tertiary amine Inokay >95％ Epichlorohydrin Inokay >99％

[0055] Preparation Example 1

[0056] The quaternary ammonium salt containing a tertiary amine and a hydroxyl group described in Formula 2, when R1 is n-dodecyl, and R2 and R3 are both ethyl, the compound is referred to as J-1. The synthesis reaction process of J-1 is as follows:

[0057]

[0058] The specific synthesis steps are as follows: put 0.2ml diethylamine into a 500mL three-necked flask, stir and slowly add 100ml 2mol / L hydrochloric acid solution. Then add 0.2mol epichlorohydrin, and the drop rate is 3-5 seconds / drop. After that, add 80mL distilled water. At 60°C, the reaction lasts for 6 hours to obtain a light yellow mixture. The pH value of the mixture is adjusted to 6.1 with hydrochloric acid. Continue to add 0.2mol dodecyldimethyl tertiary amine. The reaction lasts for 5 hours at 85°C. Use a rotary evaporator to remove the solvent in the product. Wash the solid three times with n-hexane and recrystallize it three to five times with acetone to obtain a white solid. Compound J-1 is obtained.

[0059] Preparation Example 2

[0060] The quaternary ammonium salt containing tertiary amine and hydroxyl described in formula 2, when R1 is n-hexadecyl, and R2 and R3 are both propyl, the compound is referred to as J-2. The specific synthesis steps are as follows: 0.2ml of dipropylamine is placed in a 500mL three-necked flask, stirred and slowly added with 100ml of 2mol / L hydrochloric acid solution. Then add 0.2mol of epichlorohydrin, and the drop rate is 3-5 seconds / drop. After that, add 90mL of distilled water. At 65°C, the reaction lasts for 5 hours to obtain a light yellow mixture. The pH value of the mixture is adjusted to 6.0 with hydrochloric acid. Continue to add 0.2mol of hexadecyl dimethyl tertiary amine. The reaction lasts for 4 hours at 90°C. Remove the solvent from the product with a rotary evaporator. Wash the solid three times with n-hexane and recrystallize it three to five times with acetone to obtain a white solid. Compound J-2 is obtained.

[0061] The heavy oil emulsified viscosity reducer composition was prepared using the compounds J-1 and J-2 prepared in Preparation 1-2. "Parts by weight" in the following examples means 0.5 g.

[0062] Example 1

[0063] At 40°C, 30 parts by weight of dodecylamidopropyl hydroxysulfobetaine, 10 parts by weight of J-1, 6 parts by weight of lauric acid diethanolamide, 4 parts by weight of dodecanol, and 50 parts by weight of water were added to a reactor and stirred for 40 minutes to obtain a heavy oil emulsifier viscosity reducer composition with strong foaming performance, numbered PRJ-1.

[0064] Example 2

[0065] At 20°C, 30 parts by weight of cocamidopropyl hydroxysulfobetaine, 10 parts by weight of J-2, 6 parts by weight of lauric acid diethanolamide, 4 parts by weight of octanol, and 50 parts by weight of water were added to a reactor, and the mixture was stirred for 30 minutes to prepare a heavy oil emulsifying viscosity reducer composition with strong foaming performance, numbered PRJ-2.

[0066] Example 3

[0067] At 30° C., 25 parts by weight of cocamidopropyl hydroxysulfobetaine, 8 parts by weight of J-2, 6 parts by weight of coconut acid diethanolamide, 5 parts by weight of dodecanol, and 56 parts by weight of water were added to a reactor, and the mixture was stirred for 40 minutes to obtain a heavy oil emulsifying viscosity reducer composition with strong foaming performance, numbered PRJ-3.

[0068] Example 4

[0069] At 30°C, 25 parts by weight of dodecylamidopropyl hydroxysulfobetaine, 8 parts by weight of J-1, 6 parts by weight of lauric acid diethanolamide, 5 parts by weight of octanol, and 56 parts by weight of water were added to a reactor and stirred for 30 minutes to obtain a heavy oil emulsifier viscosity reducer composition with strong foaming performance, numbered PRJ-4.

[0070] Example 5

[0071] At 15°C, 30 parts by weight of dodecylamidopropyl hydroxysulfobetaine, 10 parts by weight of J-1, 6 parts by weight of lauric acid diethanolamide, and 54 parts by weight of water were added to a reactor and stirred for 20 minutes to obtain a heavy oil emulsifier viscosity reducer composition with strong foaming performance, numbered PRJ-5.

[0072] Example 6

[0073] At 45°C, 30 parts by weight of dodecylamidopropyl hydroxysulfobetaine, 10 parts by weight of J-2, 5 parts by weight of dodecanol, and 55 parts by weight of water were added to the reactor and stirred for 20 minutes to obtain a heavy oil emulsifier viscosity reducer composition with strong foaming performance, numbered PRJ-6.

[0074] Example 7

[0075] At 20°C, 10 parts by weight of dodecylamidopropyl hydroxysulfobetaine, 3 parts by weight of J-1, 4 parts by weight of lauric acid diethanolamide, 3 parts by weight of octanol, and 80 parts by weight of water were added to a reactor and stirred for 20 minutes to obtain a heavy oil emulsifier viscosity reducer composition with strong foaming performance, numbered PRJ-7.

[0076] Example 8

[0077] At 40°C, 40 parts by weight of dodecylamidopropyl hydroxysulfobetaine, 15 parts by weight of J-1, 10 parts by weight of lauric acid diethanolamide, 6 parts by weight of octanol, and 29 parts by weight of water were added to a reactor and stirred for 60 minutes to obtain a heavy oil emulsifier viscosity reducer composition with strong foaming performance, numbered PRJ-8.

[0078] Example 9

[0079] At 40°C, 40 parts by weight of dodecylamidopropyl hydroxysulfobetaine, 3 parts by weight of J-1, 4 parts by weight of lauric acid diethanolamide, 3 parts by weight of octanol, and 50 parts by weight of water were added to a reactor and stirred for 60 minutes to obtain a heavy oil emulsifier viscosity reducer composition with strong foaming performance, numbered PRJ-9.

[0080] Comparative Example 1

[0081] At 20° C., 50 parts by weight of dodecylamidopropyl hydroxysulfobetaine and 50 parts by weight of water were added to a reaction kettle and stirred for 30 minutes to obtain a viscosity reducer, numbered DB-1.

[0082] Comparative Example 2

[0083] At 20°C, 50 parts by weight of J-1 and 50 parts by weight of water were added to a reaction kettle and stirred for 30 minutes to obtain a viscosity reducer, numbered DB-2.

[0084] Comparative Example 3

[0085] At 20°C, 50 parts by weight of J-2 and 50 parts by weight of water were added to the reaction kettle and stirred for 30 minutes to obtain a viscosity reducer, numbered DB-3.

[0086] Comparative Example 4

[0087] An industrial product of heavy oil viscosity reducer used on-site in an oil field, code-named DB-4.

[0088] Test Example 1

[0089] Evaluation of viscosity reduction rate: A viscosity reducer solution with a mass fraction of 1% was prepared using formation water from Shengli Oilfield, and the mineralization of the formation water was 8635 mg / L. A heavy oil from Shengli Oilfield was used, and the viscosity of the heavy oil at 50°C was 2521 mPa·s. 20 grams of the heavy oil sample was placed in a distillation flask; 10 grams of the viscosity reducer solution with a mass fraction of 1% in the embodiment was added to the distillation flask; the mixture was stirred at 50°C, and the viscosity at 50°C was measured using a rheometer to calculate the viscosity reduction rate.

[0090] Test Example 2

[0091] Evaluation of foaming performance and foam stabilization performance: The foaming height and half-life of the viscosity reducer composition were determined by the Ross-mils method. The specific steps are as follows: a viscosity reducer solution with a mass fraction of 1% was prepared using formation water from Shengli Oilfield, and the formation water salinity was 8635 mg / L. At 50°C, 200 mL of the viscosity reducer solution was allowed to flow freely in a dropper and impacted 50 mL of the viscosity reducer solution in a graduated measuring tube, and the foam height and the time when the foam disappeared by 50% were recorded.

[0092] The test results of viscosity reduction rate, foam height and half-life are shown in Table 2.

[0093] Table 2 Performance test results of different viscosity reducer compositions

[0094]

[0095] It can be seen that the heavy oil emulsified viscosity reducer composition with strong foaming performance provided by the present invention can significantly improve the viscosity reduction rate, foaming height and half-life of a single compound, and can not only significantly reduce the viscosity of heavy oil, but also has strong foaming performance and foam stabilization ability.

[0096] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A heavy oil emulsified viscosity reducer composition, characterized in that: The composition comprises alkylamidopropyl hydroxysulfonate betaine, a quaternary ammonium salt compound containing a tertiary amine and a hydroxyl group, and water. Based on the total mass of the composition being 100%, the content of the alkylamidopropyl hydroxysulfonate betaine is 10%-40%, preferably 25%-30%; the content of the quaternary ammonium salt compound containing a tertiary amine and a hydroxyl group is 3%-15%, preferably 8%-10%.

2. The thick oil emulsified viscosity reducer composition according to claim 1, characterized in that: The structure of the alkylamidopropyl hydroxysulfonate betaine is shown in Formula 1: Among them, R is from C6 to C 24 Any of the alkyl and alkenyl groups, preferably C8 to C 20 Alkyl, most preferably C 10 ~C 16 of normal alkyl.

3. The thick oil emulsified viscosity reducer composition according to claim 1, characterized in that: The structure of the quaternary ammonium salt compound containing a tertiary amine and a hydroxyl group is shown in Formula 2: Wherein the group R1 is C 4-28 Any of alkyl and alkenyl, preferably C 12-18 normal alkyl; R2 and R3 are each independently selected from CH3, C2H5, 1C3H7 or C4H9, preferably C2H5; X is Cl or Br.

4. The thick oil emulsified viscosity reducer composition according to claim 1, characterized in that: The composition further comprises a foam stabilizer and / or a co-surfactant, wherein the content of the foam stabilizer accounts for 0-10% of the total mass of the heavy oil emulsified viscosity reducer, preferably 4%-6%; the content of the co-surfactant accounts for 0%-6% of the total mass of the heavy oil emulsified viscosity reducer, preferably 3%-5%.

5. The thick oil emulsified viscosity reducer composition according to claim 1, characterized in that: The foam stabilizer is fatty acid diethanolamide shown in Formula 3: Among them, R4 is composed of C8-C 20 Saturated fatty acids, C8-C 20 Vegetable oil fatty acids or C8-C 20 Preferably, the C8-C 20 The vegetable oil fatty acid is provided by at least one of coconut oleic acid, cotton oleic acid and tall oil acid. 12 -C 18 Normal saturated fatty acids or C 12 -C 18 Provided by normal vegetable oil fatty acids.

6. The thick oil emulsified viscosity reducer composition according to claim 1, characterized in that: The co-surfactant is an alcohol having 2 to 14 carbon atoms, preferably one or more of n-heptanol, n-octanol and dodecanol.

7. Use of the heavy oil emulsified viscosity reducer composition according to claims 1 to 6 in single well huff and puff production of heavy oil reservoirs.

8. The use according to claim 7, characterized in that The heavy oil emulsified viscosity reducer composition is combined with N2 or CO2 throughput.

9. The use according to claim 7, characterized in that A certain mass fraction of the heavy oil emulsified viscosity reducer composition is injected into the oil well, preferably 0.3%-5%, more preferably 1%-3%, and then a high-pressure N2 or / and CO2 plug is injected into the oil well, and then the well is shut down.

10. Use of the heavy oil emulsified viscosity reducer composition according to claims 1 to 6 in chemical flooding of heavy oil reservoirs.

11. The use according to claim 10, characterized in that A certain mass fraction of the heavy oil emulsified viscosity reducer composition is first pulse injected into the injection well, preferably 0.1%-3%, more preferably 0.3%-1.5%, and then N2 and / or CO2 plugs are injected into the injection well, followed by water injection.

12. The use according to claim 11, characterized in that The heavy oil emulsified viscosity reducer composition and N2 or CO2 are alternately injected into several slugs.

13. The use according to claim 10, characterized in that The heavy oil emulsified viscosity reducer composition and N2 or / and CO2 plug are injected into the injection well simultaneously, preferably the mass fraction of the viscosity reducer is 0.1%-3%, more preferably the mass fraction is 0.3%-1.5%.

14. The use according to claim 13, characterized in that Preferably, after the foam blocks the crossflow channel, the injection of N2 and / or CO2 plugs is stopped, and the injection of the viscosity reducer solution continues.

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