阅读说明：本技术 一种用于原油降凝的聚合物及其制备方法和应用 (Polymer for crude oil pour point depression and preparation method and application thereof ) 是由 崔仕章 修宗明 王黎明 宋新旺 高瑞美 吕志凤 于 2021-06-03 设计创作，主要内容包括：本申请公开了一种用于原油降凝的聚合物及其制备方法和应用,该聚合物含有结构单元A、结构单元B和结构单元C,其中,所述结构单元A为具有式Ⅰ所示结构的结构单元,所述结构单元B为具有式Ⅱ或式Ⅲ所示结构的结构单元,所述结构单元C为具有式Ⅳ所示结构的结构单元；其中,以所述聚合物的重量为基准,所述结构单元A的重量百分含量为5％～25％,所述结构单元B的重量百分含量为40％～85％,所述结构单元C的重量百分含量为10％～35％。该聚合物中富马酸聚合物的刚性较好,极性部分分布均匀,其长链结构可以与高凝原油中的蜡晶作用,其次酰胺结构极性较强,能够更好的调整蜡晶结构,极性基团与高凝原油中的胶质、沥青质作用,降低原油的凝点。(The application discloses a polymer for crude oil pour point depression, a preparation method and an application thereof, wherein the polymer comprises a structural unit A, a structural unit B and a structural unit C, wherein the structural unit A is a structural unit with a structure shown in a formula I, the structural unit B is a structural unit with a structure shown in a formula II or a formula III, and the structural unit C is a structural unit with a structure shown in a formula IV; based on the weight of the polymer, the weight percentage of the structural unit A is 5-25%, the weight percentage of the structural unit B is 40-85%, and the weight percentage of the structural unit C is 10-35%. The fumaric acid polymer in the polymer has good rigidity and uniform distribution of polar parts, the long-chain structure of the fumaric acid polymer can act with wax crystals in the high-condensation crude oil, the amide structure has strong polarity, the wax crystal structure can be better adjusted, and polar groups act with colloid and asphaltene in the high-condensation crude oil, so that the condensation point of the crude oil is reduced.)

1. The polymer for reducing the pour point of crude oil is characterized by comprising a structural unit A, a structural unit B and a structural unit C, wherein the structural unit A is a structural unit with a structure shown in a formula I, the structural unit B is a structural unit with a structure shown in a formula II or a formula III, and the structural unit C is a structural unit with a structure shown in a formula IV; based on the weight of the polymer, the weight percentage of the structural unit A is 5-25%, the weight percentage of the structural unit B is 40-85%, and the weight percentage of the structural unit C is 10-35%;

wherein R is₁One selected from H and C1-C5 alkyl, R₂One selected from H and C1-C5 alkyl, R₃One selected from C12-C28 alkyl, R₄One selected from C12-C28 alkyl.

2. The polymer of claim 1, wherein R is₁One selected from H and C1-C3 alkyl, R₂One selected from H and C1-C3 alkyl, R₃One selected from C16-C24 alkyl, R₄One selected from C16-C24 alkyl;

preferably, R₁One selected from H and C1-C2 alkyl, R₂One selected from H and C1-C2 alkyl, R₃One selected from C18-C22 alkyl, R₄One selected from C18-C22 alkyl.

3. A method of preparing the polymer of claim 1, comprising the steps of:

(1) in an organic solvent, mixing the components in a molar ratio of 1-5: 8-17: 2 to 7 with R₁-CH＝C(R₂) An olefinic nitrile monomer represented by (CN), fumaric acid and styreneCarrying out polymerization reaction under the action of a hair agent to obtain a terpolymer;

(2) the terpolymer is reacted with C12-C28 fatty primary amine to prepare the polymer for reducing the pour point of the crude oil.

4. The preparation method according to claim 3, wherein the molar ratio of the terpolymer to the C12-C28 primary aliphatic amine is 1: 1.2-2;

preferably, the molar ratio of the terpolymer to the C12-C28 fatty primary amine is 1: 1.5-2;

preferably, the fatty primary amine is selected from at least one of C16-C22;

preferably, the molecular weight of the polymer for depressing the pour point of the crude oil is 3000-5000.

5. The production method according to claim 3, wherein in the step (1), the organic solvent is at least one selected from the group consisting of toluene, xylene, and ethylbenzene;

the initiator is selected from at least one of benzoyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide and azobisisobutyronitrile;

the temperature of the polymerization reaction is 70-90 ℃, and the time is 4-8 h; and/or

The dosage of the initiator is 0.5-3% of the total mass of the monomers.

6. The production method according to claim 3, wherein in the step (2), the reaction comprises the steps of: reacting the terpolymer with C12-C28 fatty primary amine at 105-120 ℃ for 1-4 h, heating to 150-160 ℃, and dehydrating for 0.8-2 h;

preferably, the reaction temperature is 110-115 ℃ and the reaction time is 2-3 h.

7. A pour point depressant for crude oil, the pour point depressant comprising: polymers and synergists for pour point depression of crude oils;

the polymer comprises the polymer of claim 1 or 2 or the polymer obtained by the preparation method of any one of claims 3 to 6;

preferably, the mass ratio of the polymer for reducing the pour point of the crude oil to the synergist is 10: 1.2-4;

preferably, the mass ratio of the polymer for reducing the pour point of the crude oil to the synergist is 10: 1.5 to 3.

8. The crude oil pour point depressant according to claim 7, wherein the synergist comprises, by mass, 5-8: 1-2 of allyl polyether and glyceryl oleate;

preferably, the allyl polyether is selected from one or more of methyl-terminated allyl polyether, butyl-terminated allyl polyether and ester-terminated allyl polyether;

preferably, the method for obtaining the synergist comprises the following steps: mixing allyl polyether and glyceryl oleate, and performing ultrasonic dispersion to obtain the synergist;

preferably, the ultrasonic dispersion time is 15-20 min, and the temperature is 20-35 ℃.

9. A method of preparing the pour point depressant for crude oil of claim 7, comprising the steps of: stirring and mixing a polymer for reducing the pour point of the crude oil and a synergist to prepare the pour point depressant for the crude oil;

preferably, the stirring temperature is 50-85 ℃ and the stirring time is 20-40 min.

10. Use of a polymer according to claim 1 or 2, a polymer obtained by the preparation method according to any one of claims 3 to 6, a pour point depressant for crude oil according to claim 7 or 8, or a pour point depressant for crude oil obtained by the preparation method according to claim 9 for pour point depressant of waxy crude oil.

Technical Field

The application relates to a polymer for crude oil pour point depression and a preparation method thereof, a crude oil pour point depressant and a preparation method thereof, and application of the polymer for crude oil pour point depression or the crude oil pour point depressant in wax-containing crude oil pour point depression, belonging to the technical field of oil field chemicals.

Background

Most of crude oil in China belongs to wax-containing crude oil, wax crystals are easily separated from the wax-containing crude oil when the temperature is close to a wax precipitation point, the wax crystals are more and more in number and grow and aggregate with further reduction of the temperature, and a three-dimensional mesh-structured cerate-shaped substance is formed to enable the crude oil to lose liquidity. This results in high pour point and poor low temperature fluidity of the waxy crude oil, which causes difficulties in the recovery and transportation of the crude oil.

The pour point depressant can change the crystallization state of paraffin in the crude oil through nucleation, adsorption, eutectic effect and solubilization, so that the paraffin is not easy to form a space network structure, and macroscopically shows the reduction of the pour point and the viscosity of the crude oil. The pour point depressant is added into the crude oil, so that the low-temperature fluidity of the crude oil can be greatly improved when the addition amount is small, the efficiency of the crude oil in the processes of collection, transportation, storage and transportation and the like is improved, and the production cost is reduced.

The EVA pour point depressant is a ethylene and vinyl acetate copolymer pour point depressant, is low in price and has been successfully applied to some oil fields, but different crude oils are applicable to different types of pour point depressants due to strong pertinence, and the pour point depression effect is poor. The maleic anhydride copolymer pour point depressant is a pour point depressant formed by copolymerizing maleic anhydride and a plurality of monomers, is widely applied due to excellent pour point depression effect and strong applicability, but the chemical bond contained in the main chain and the branched chain in the comb-shaped structure is single, so that the pour point depression effect is limited.

Disclosure of Invention

In order to solve the problems, the polymer for pour point depression of the crude oil, the crude oil pour point depressant and the preparation method thereof are provided, wherein amidated alkene nitrile monomer, fumaric acid and styrene terpolymer are used in the crude oil pour point depressant, and the polymer and a wax paste substance in the crude oil act to ensure that the polymer is not easy to form a space network structure, thereby achieving good effects of pour point depression and viscosity reduction.

According to one aspect of the application, a polymer for crude oil pour point depression is provided, and the polymer comprises a structural unit A, a structural unit B and a structural unit C, wherein the structural unit A is a structural unit with a structure shown in a formula I, the structural unit B is a structural unit with a structure shown in a formula II or a formula III, and the structural unit C is a structural unit with a structure shown in a formula IV; wherein, based on the weight of the polymer, the weight percentage content of the structural unit A is 5-25%, the weight percentage content of the structural unit B is 40-85%, and the weight percentage content of the structural unit C is 10-35%:

wherein R is₁One selected from H and C1-C5 alkyl, R₂One selected from H and C1-C5 alkyl, R₃One selected from C12-C28 alkyl, R₄One selected from C12-C28 alkyl.

Preferably, the lower limit of the weight percentage content of the structural unit a may be 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23% or 24%, and the upper limit of the weight percentage content of the structural unit a may be 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23% or 24%. The lower limit of the weight percentage of the structural unit B may be 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%, and the upper limit of the weight percentage of the structural unit B may be 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%. The lower limit of the weight percentage of the structural unit C may be 15%, 20%, 25% or 30%, and the upper limit of the weight percentage of the structural unit C may be 15%, 20%, 25% or 30%.

Wherein R1 is selected from one of H and C1-C5 alkyl, R2 is selected from one of H and C1-C5 alkyl, R3 is selected from one of C12-C28 alkyl, and R4 is selected from one of C12-C28 alkyl.

Further, R1 is selected from one of H and C1-C3 alkyl, R2 is selected from one of H and C1-C3 alkyl, R3 is selected from one of C16-C24 alkyl, and R4 is selected from one of C16-C24 alkyl;

preferably, R1 is selected from one of H and C1-C2 alkyl, R2 is selected from one of H and C1-C2 alkyl, R3 is selected from one of C18-C22 alkyl, and R4 is selected from one of C18-C22 alkyl.

According to another aspect of the present application, there is provided a method for preparing the polymer, comprising the steps of:

(1) in an organic solvent, mixing the components in a molar ratio of 1-5: 8-17: 2-7 of an alkene nitrile monomer represented by R1-CH ═ C (R2) (CN), fumaric acid and styrene, and carrying out a polymerization reaction under the action of an initiator to obtain a terpolymer;

(2) the terpolymer is reacted with C12-C28 fatty primary amine to prepare the polymer for reducing the pour point of the crude oil.

In one embodiment, the molar ratio of the terpolymer to the C12-C28 primary aliphatic amine is 1: 1.2-2; preferably, the molar ratio of the terpolymer to the C12-C28 fatty primary amine is 1: 1.5-2; preferably, the fatty primary amine is selected from at least one of C16-C22; preferably, the molecular weight of the polymer for depressing the pour point of the crude oil is 3000-5000.

In one embodiment, in step (1), the organic solvent is at least one selected from the group consisting of toluene, xylene, and ethylbenzene; the initiator is selected from at least one of benzoyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide and azobisisobutyronitrile; the temperature of the polymerization reaction is 70-90 ℃, and the time is 4-8 h; and/or the dosage of the initiator is 0.5-3% of the total mass of the monomers.

In one embodiment, in step (2), the reaction comprises the steps of: reacting the terpolymer with C12-C28 fatty primary amine at 105-120 ℃ for 1-4 h, heating to 150-160 ℃, and dehydrating for 0.8-2 h; preferably, the reaction temperature is 110-115 ℃ and the reaction time is 2-3 h.

According to another aspect of the present application, there is provided a pour point depressant for crude oil, the pour point depressant comprising: polymers and synergists for pour point depression of crude oils;

the polymer comprises the polymer described in any one of the above or the polymer obtained by the preparation method described in any one of the above;

preferably, the mass ratio of the polymer for reducing the pour point of the crude oil to the synergist is 10: 1.2-4;

preferably, the mass ratio of the polymer for reducing the pour point of the crude oil to the synergist is 10: 1.5 to 3.

In an embodiment, the synergist comprises, by mass, 5-8: 1-2 of allyl polyether and glyceryl oleate;

preferably, the allyl polyether is selected from one or more of methyl-terminated allyl polyether, butyl-terminated allyl polyether and ester-terminated allyl polyether;

preferably, the method for obtaining the synergist comprises the following steps: mixing allyl polyether and glyceryl oleate, and performing ultrasonic dispersion to obtain the synergist;

preferably, the ultrasonic dispersion time is 15-20 min, and the temperature is 20-35 ℃.

In one embodiment, the method includes the steps of: stirring and mixing a polymer for reducing the pour point of the crude oil and a synergist to prepare the pour point depressant for the crude oil; preferably, the stirring temperature is 50-85 ℃ and the stirring time is 20-40 min.

According to another aspect of the present application, there is provided a polymer as defined in any one of the preceding claims, a pour point depressant for crude oil as defined in any one of the preceding claims, or a pour point depressant for crude oil as defined in any one of the preceding claims, for use in pour point depressant for waxy crude oils.

Benefits of the present application include, but are not limited to:

(1) according to the polymer for reducing the pour point of the crude oil, in the amidated alkene nitrile monomer, the fumaric acid and styrene terpolymer, the polar parts are uniformly distributed, the rigidity of the fumaric acid polymer is better, the long-chain structure of the fumaric acid polymer can act with the wax crystal structure in the high pour point crude oil, the amide structure can better adjust the wax crystal structure, the addition of nitrile bonds is equivalent to the addition of a third monomer in the copolymer, the main chain length of the polymer is increased, the molecular structure of a side chain is enriched, the branching degree of the copolymer is increased, and therefore the pour point of the crude oil is favorably reduced.

(2) According to the crude oil pour point depressant, allyl polyether and glyceryl oleate are added into the terpolymer of alkene nitrile monomers, fumaric acid and styrene, so that the copolymer can be quickly dissolved into crude oil, effective groups of the copolymer are more efficiently combined with paraffin in the crude oil, the interaction between the copolymer and colloid and asphaltene in high-freezing crude oil is increased, the freezing point of the crude oil is reduced, the low-temperature fluidity of the crude oil is improved, and the crude oil is convenient to extract and transport.

(3) According to the preparation method of the crude oil pour point depressant, the preparation conditions are mild, the process is simple, the operation is convenient, and the industrial popularization and the application are facilitated.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

Unless otherwise specified, the raw materials and reagents in the examples of the present application were all purchased commercially.

Example 1

A preparation method of a crude oil pour point depressant specifically comprises the following steps:

(1) preparation of the polymer:

1) mixing the components in a molar ratio of 2: 15: 3, adding acrylonitrile, fumaric acid and styrene which are monomers into dimethylbenzene of which the mass is half of the total mass of the monomers, keeping the temperature and stirring for 30min at the temperature of 80 ℃, adding benzoyl peroxide, and reacting for 6h, wherein the dosage of the benzoyl peroxide is 1 percent of the total mass of the monomers to prepare a terpolymer;

2) mixing a mixture of 1: 2, mixing the terpolymer with C18 fatty primary amine, carrying out amidation reaction at 115 ℃, reacting for 3h, heating to 155 ℃, dehydrating for 1h to obtain the terpolymer (in the formula I, R₁Is H, R₂Is H; in the formula III, R₃Is C18 alkyl, R₄Is C18 alkyl), the molecular weight of the polymer is 3000-5000;

(2) preparation of the synergist:

dropwise adding the glycerol oleate into the methyl-terminated allyl polyether, wherein the mass ratio of the methyl-terminated allyl polyether to the glycerol oleate is 6: 2, carrying out ultrasonic dispersion while dropwise adding, wherein the ultrasonic dispersion time is 20min and the temperature is 30 ℃, and obtaining the synergist;

(3) mixing the components in a mass ratio of 10: 2, mixing the polymer and the synergist, heating to 75 ℃, and stirring for 30min to obtain the pour point depressant No. 1.

Example 2

A preparation method of a crude oil pour point depressant specifically comprises the following steps:

(1) preparation of the polymer:

1) mixing the components in a molar ratio of 2: 15: 3, adding acrylonitrile, fumaric acid and styrene which are monomers into toluene with half of the total mass of the monomers, keeping the temperature and stirring for 30min at the temperature of 80 ℃, adding tert-butyl hydroperoxide, and reacting for 6h, wherein the dosage of the tert-butyl hydroperoxide is 0.5 percent of the total mass of the monomers to prepare the terpolymer;

2) mixing a mixture of 1: 2, mixing the terpolymer with C18 fatty primary amine, carrying out amidation reaction at 115 ℃, reacting for 3h, and heatingDehydrating at 155 deg.C for 1h to obtain terpolymer (in formula I, R₁Is H, R₂Is H; in the formula III, R₃Is C18 alkyl, R₄Is C18 alkyl), the molecular weight of the polymer is 3000-5000;

(2) preparation of the synergist:

dropwise adding the glycerol oleate into the methyl-terminated allyl polyether, wherein the mass ratio of the methyl-terminated allyl polyether to the glycerol oleate is 6: 2, carrying out ultrasonic dispersion while dropwise adding, wherein the ultrasonic dispersion time is 20min and the temperature is 30 ℃, and obtaining the synergist;

(3) mixing the components in a mass ratio of 10: 2, mixing the polymer and the synergist, heating to 75 ℃, and stirring for 30min to obtain the pour point depressant No. 2.

Example 3

A preparation method of a crude oil pour point depressant specifically comprises the following steps:

(1) preparation of the polymer:

1) mixing a mixture of 3: 13: 4, adding monomer methacrylonitrile, fumaric acid and styrene into xylene with the total mass of the monomer being 2/3, keeping the temperature and stirring for 40min at the temperature of 75 ℃, adding cumene hydroperoxide, reacting for 7h, wherein the dosage of the cumene hydroperoxide is 2 percent of the total mass of the monomer, and preparing the terpolymer;

2) mixing a mixture of 1: 1.2 mixing the terpolymer with C20 fatty primary amine, carrying out amidation reaction at 105 ℃, reacting for 4h, heating to 150 ℃, dehydrating for 1.5h to obtain the terpolymer (in formula I, R₁Is H, R₂Is C1 alkyl; in the formula II or III, R₃Is C20 alkyl, R₄Is C20 alkyl), the molecular weight of the polymer is 3000-5000;

(2) preparation of the synergist:

dropwise adding the glycerol oleate into the butyl-terminated allyl polyether, wherein the mass ratio of the butyl-terminated allyl polyether to the glycerol oleate is 5: 1, carrying out ultrasonic dispersion while dropwise adding, wherein the ultrasonic dispersion time is 15min and the temperature is 35 ℃, and obtaining the synergist;

(3) mixing the components in a mass ratio of 10: 1.2, mixing the polymer with a synergist, heating to 85 ℃, and stirring for 20min to obtain the pour point depressant No. 3.

Example 4

A preparation method of a crude oil pour point depressant specifically comprises the following steps:

(1) preparation of the polymer:

1) mixing the components in a molar ratio of 2: 15: 3, adding the 2-methyl-2-butenenitrile monomer, fumaric acid and styrene into 2/3 toluene in the total mass of the monomers, stirring at the temperature of 80 ℃ for 30min, adding benzoyl peroxide, and reacting for 6h, wherein the dosage of the benzoyl peroxide is 0.5-3% of the total mass of the monomers, thus preparing the terpolymer;

2) mixing a mixture of 1: 2, mixing the terpolymer with C18 fatty primary amine, carrying out amidation reaction at 115 ℃, reacting for 3h, heating to 155 ℃, dehydrating for 1h to obtain the terpolymer (in the formula I, R₁Is C1 alkyl, R₂Is C1 alkyl; in the formula III, R₃Is C18 alkyl, R₄Is C18 alkyl), the molecular weight of the polymer is 3000-5000;

(2) preparation of the synergist:

dropwise adding the glycerol oleate into the methyl-terminated allyl polyether, wherein the mass ratio of the methyl-terminated allyl polyether to the glycerol oleate is 6: 2, carrying out ultrasonic dispersion while dropwise adding, wherein the ultrasonic dispersion time is 20min and the temperature is 30 ℃, and obtaining the synergist;

(3) mixing the components in a mass ratio of 10: 2, mixing the polymer and the synergist, heating to 75 ℃, and stirring for 30min to obtain the pour point depressant No. 4.

Example 5

A preparation method of a crude oil pour point depressant specifically comprises the following steps:

(1) preparation of the polymer:

1) mixing a mixture of 1: 15: 2, adding cis-2-pentenenitrile, fumaric acid and styrene which are monomers into toluene with half of the total mass of the monomers, keeping the temperature and stirring for 20min at 85 ℃, adding benzoyl peroxide, and reacting for 5h, wherein the dosage of the benzoyl peroxide is 3 percent of the total mass of the monomers, thus preparing the terpolymer;

2) mixing a mixture of 1: 1.5 the above terpolymer with C22, mixing fatty primary amine, carrying out amidation reaction at 120 ℃, reacting for 1h, heating to 160 ℃, and dehydrating for 1h to obtain the terpolymer (in the formula I, R₁Is H, R₂Is C2 alkyl; in the formula II or III, R₃Is C18 alkyl, R₄Is C18 alkyl), the molecular weight of the polymer is 3000-5000;

(2) preparation of the synergist:

dropwise adding the glycerol oleate into the methyl-terminated allyl polyether, wherein the mass ratio of the methyl-terminated allyl polyether to the glycerol oleate is 8: 2, carrying out ultrasonic dispersion while dropwise adding, wherein the ultrasonic dispersion time is 20min, and the temperature is 35 ℃, so as to obtain the synergist;

(3) mixing the components in a mass ratio of 10: 4, mixing the polymer and the synergist, heating to 50 ℃, and stirring for 40min to obtain the pour point depressant No. 5.

Example 6

A preparation method of a crude oil pour point depressant specifically comprises the following steps:

(1) preparation of the polymer:

1) mixing a mixture of 3: 5: 4, adding acrylonitrile, fumaric acid and styrene which are monomers into dimethylbenzene of which the mass is half of the total mass of the monomers, keeping the temperature and stirring for 30min at the temperature of 80 ℃, adding benzoyl peroxide, and reacting for 6h, wherein the dosage of the benzoyl peroxide is 1 percent of the total mass of the monomers to prepare a terpolymer;

2) mixing a mixture of 1: 2, carrying out amidation reaction at 105-120 ℃, reacting for 3h, heating to 150 ℃, and dehydrating for 1h to obtain the terpolymer (in the formula I, R is₁Is H, R₂Is H; in the formula III, R₃Is C20 alkyl, R₄Is C20 alkyl), the molecular weight of the polymer is 3000-5000;

(2) preparation of the synergist:

dropwise adding the glycerol oleate into the methyl-terminated allyl polyether, wherein the mass ratio of the methyl-terminated allyl polyether to the glycerol oleate is 7: 1, carrying out ultrasonic dispersion while dropwise adding, wherein the ultrasonic dispersion time is 20min and the temperature is 35 ℃, and obtaining the synergist;

(3) mixing the components in a mass ratio of 10: 3, mixing the polymer and the synergist, heating to 75 ℃, and stirring for 30min to obtain the pour point depressant No. 6.

Example 7

A preparation method of a crude oil pour point depressant specifically comprises the following steps:

(1) preparation of the polymer:

1) mixing a mixture of 3: 14: 3, adding acrylonitrile, fumaric acid and styrene which are monomers into ethylbenzene with half of the total mass of the monomers, keeping the temperature at 75 ℃ and stirring for 40min, adding azobisisobutyronitrile, reacting for 7h, wherein the dosage of the azobisisobutyronitrile is 2% of the total mass of the monomers, and preparing the terpolymer;

2) mixing a mixture of 1: 2, mixing the terpolymer with C18 fatty primary amine, carrying out amidation reaction at 110 ℃, reacting for 2h, heating to 155 ℃, dehydrating for 2h, and obtaining the terpolymer (in the formula I, R₁Is H, R₂Is H; in the formula III, R₃Is C18 alkyl, R₄Is C18 alkyl), the molecular weight of the polymer is 3000-5000;

(2) preparation of the synergist:

dropwise adding the glycerol oleate into the methyl-terminated allyl polyether, wherein the mass ratio of the methyl-terminated allyl polyether to the glycerol oleate is 6: 1, carrying out ultrasonic dispersion while dropwise adding, wherein the ultrasonic dispersion time is 20min and the temperature is 30 ℃, and obtaining the synergist;

(3) mixing the components in a mass ratio of 10: 3, mixing the polymer and the synergist, heating to 80 ℃, and stirring for 30min to obtain the pour point depressant No. 7.

Example 8

A preparation method of a crude oil pour point depressant specifically comprises the following steps:

(1) preparation of the polymer:

1) mixing the components in a molar ratio of 2: 15: 3, adding acrylonitrile, fumaric acid and styrene which are monomers into ethylbenzene with half of the total mass of the monomers, keeping the temperature at 85 ℃, stirring for 20min, adding benzoyl peroxide, reacting for 6h, wherein the dosage of the benzoyl peroxide is 0.5 percent of the total mass of the monomers, and preparing a terpolymer;

2) will moleThe ratio is 1: 2, mixing the terpolymer with C22 fatty primary amine, carrying out amidation reaction at 115 ℃, reacting for 3h, heating to 150 ℃, and dehydrating for 0.8h to obtain the terpolymer (in the formula I, R₁Is H, R₂Is H; in the formula III, R₃Is C20 alkyl, R₄Is C20 alkyl), the molecular weight of the polymer is 3000-5000;

(2) preparation of the synergist:

dropwise adding the glycerol oleate into the methyl-terminated allyl polyether, wherein the mass ratio of the methyl-terminated allyl polyether to the glycerol oleate is 7: 2, carrying out ultrasonic dispersion while dropwise adding, wherein the ultrasonic dispersion time is 20min and the temperature is 30 ℃, and obtaining the synergist;

(3) mixing the components in a mass ratio of 10: 1.5, mixing the polymer with a synergist, heating to 75 ℃, and stirring for 30min to obtain the pour point depressant No. 8.

Comparative example 1

The procedure is as in example 2, except that: (1) preparation of the polymer: 1) mixing the components in a molar ratio of 2: 15: 3, adding acrylic ester, fumaric acid and styrene into xylene with the mass of 2 times of the total mass of the monomers, and completely carrying out the same steps as the example 2 to obtain pour point depressant D1 #.

Comparative example 2

The procedure is as in example 2, except that: (1) the polymer was prepared without step 2), i.e., using the unamidated terpolymer, and the rest of the procedure was exactly the same as in example 2, yielding pour point depressant D2 #.

Comparative example 3

The procedure is as in example 2, except that: preparing the synergist in the step (2), and mixing the components in the step (3) in a mass ratio of 10: 1.2 mixing the polymer with glyceryl oleate, heating to 85 deg.C, stirring for 20min, and performing the same procedures as in example 2 to obtain crude oil pour point depressant D3 #.

Comparative example 4

The procedure is as in example 2, except that: preparing the synergist in the step (2), and mixing the components in the step (3) in a mass ratio of 10: 1.2 mixing the above polymer with methyl terminated allyl polyether, heating to 85 deg.C, stirring for 20min, and performing the same procedures as in example 2 to obtain pour point depressant D4 #.

Comparative example 5

The procedure is as in example 2, except that: (2) preparation of the synergist: mixing the glyceryl oleate and the methyl-terminated allyl polyether for 30min under stirring to obtain the synergist; the rest of the procedure was exactly the same as in example 2, yielding pour point depressant D5 #.

Application example 1 pour point depressant pour point depressing effect test

1. In the embodiment, different pour point depressants are respectively used for carrying out pour point depression amplitude test experiments on crude oil in a West Africa block according to the method in GB/T26985-2018, and each set of pour point depressants are respectively carried out with the pour point test experiments at the same temperature (specifically 80 ℃).

The results of the tests for each pour point depressant are shown in table 1.

TABLE 1

Pour point depressant for crude oil	Additive concentration/ppm	After addition the congealing point/. deg.C	Pour Point Depression amplitude/deg.C
				Blank space	0	35	——
Pour point depressant 1#	1000	20	15
				Pour point depressant No. 2	1000	21	14
Pour point depressant 3#	1000	21	14
				Pour point depressant 4#	1000	21	14
Pour point depressant 5#	1000	20	15
				Pour point depressant 6#	1000	20	15
Pour point depressant 7#	1000	20	15
				Pour point depressant 8#	1000	21	14
Pour point depressant D1#	1000	28	7
				Pour point depressant D2#	1000	31	4
Pour point depressant D3#	1000	30	5
				Pour point depressant D4#	1000	27	8
Pour point depressant D5#	1000	30	5

As is clear from Table 1, the pour point depressants for crude oils provided in examples 1 to 8 exhibited large pour point depressing range and the pour point depressing effect was superior to that of comparative examples 1 to 5.

2. Measurement of viscosity reduction Rate

The viscosity of waxy crude oil from an oil field is 10000 mPa.s at 50 ℃ and the wax content is 29 percent, the pour point depressant is mixed with the waxy crude oil according to the mass ratio of 1:9, the temperature of the waxy crude oil is kept constant for 1h at 50 ℃, and then the viscosity reduction rate of the obtained waxy crude oil emulsion to the waxy crude oil is measured by an NDJ-1B rotary viscometer within 20s, wherein the pour point depressants 1# to 8# prepared in the embodiment of the application and the pour point depressants D1# to 5# prepared in the comparative example are shown in Table 1.

TABLE 1

Sample (I)	Viscosity (mPa. s)	Viscosity reduction Rate (%)
			Pour point depressant 1#	987	90.13
Pour point depressant No. 2	860	91.4
			Pour point depressant 3#	993	90.07
Pour point depressant 4#	1002	89.98
			Pour point depressant 5#	910	90.9
Pour point depressant 6#	932	90.68
			Pour point depressant 7#	938	90.62
Pour point depressant 8#	976	90.24
			Pour point depressant D1#	3428	65.72
Pour point depressant D2#	4029	59.71
			Pour point depressant D3#	3897	61.03
Pour point depressant D4#	4296	57.04
			Pour point depressant D5#	3677	63.23

From the results in table 1, the pour point depressant prepared by the method has good viscosity reduction effect on the wax-containing crude oil, wherein the viscosity reduction effect of pour point depressant No. 2 is the best, and the viscosity reduction rate reaches 91.4%.

The above description is only an example of the present application, and the protection scope of the present application is not limited by these specific examples, but is defined by the claims of the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the technical idea and principle of the present application should be included in the protection scope of the present application.