Natural gas hydrate kinetic inhibitor containing multi-element ring structure and preparation method of natural gas hydrate kinetic inhibitor

Abstract

The invention relates to the technical field of natural gas hydrate inhibitors, in particular to a natural gas hydrate kinetic inhibitor containing a multi-ring structure and a preparation method of the natural gas hydrate kinetic inhibitor. The natural gas hydrate kinetic inhibitor comprises the following raw materials: acryloyl morpholine, maleic anhydride, dimethylamino propyl acrylamide, isohexylene glycol, an initiator, a chain transfer agent and a chain terminator. The preparation method comprises the following steps: dissolving acryloyl morpholine, maleic anhydride and dimethylamino propyl acrylamide in an isohexylene glycol solution, and carrying out free radical polymerization reaction under the action of an initiator, a chain transfer agent and a chain terminator. The natural gas hydrate kinetic inhibitor containing the multi-element ring structure is added in the natural gas injection-production and gathering and transportation process, can participate in generation of a hydrate crystal structure through a specific multi-element ring, effectively inhibits growth of hydrate crystals and prevents generation of large-particle hydrates, and has the advantages of being good in inhibition effect, small in dosage and low in comprehensive cost.

Description

Technical Field

[0001] The invention relates to the technical field of natural gas hydrate inhibitors, and is a natural gas hydrate kinetic inhibitor containing a polycyclic structure and a preparation method thereof. Background Art

[0002] During the injection, production and gathering process of natural gas, low molecular weight hydrocarbons, gases such as hydrogen sulfide and carbon dioxide and water in the pipeline will form hydrates under certain temperature and pressure conditions. At the very least, the gas channel will be reduced, and at worst, the pipeline or equipment will be blocked, seriously restricting the development of oilfield gas reservoirs, the application of miscible drive and the construction of gas storage facilities, and affecting safe production.

[0003] At present, the methods for preventing hydrate formation are mainly divided into physical methods and chemical methods. The physical method is mainly to make the oil and gas system not have the thermodynamic conditions for the formation of hydrates, including water removal, heating, pressure reduction and the combination of these methods. The chemical method is to change the phase equilibrium, crystal nucleation, crystal growth or aggregation properties of the system by adding chemical reagents. It has the advantages of simplicity, economy and good effect. It is the most widely used method to prevent hydrate formation.

[0004] Hydrate inhibitors mainly include traditional thermodynamic inhibitors and conventional kinetic inhibitors. Thermodynamic inhibitors can change the thermodynamic conditions of natural gas hydrate formation, lowering its equilibrium temperature and increasing its equilibrium pressure, thereby inhibiting the formation of hydrates. However, their dosage is large (a certain mass fraction must be reached to achieve the ideal inhibition effect), they are difficult to recover and recycle, the cost of use is high, and some thermodynamic inhibitors are also toxic. Conventional kinetic hydrate inhibitors inhibit hydrate nucleation or hinder the growth of crystal nuclei through the action of their own functional groups. They have the advantages of good inhibition effect, low dosage, economy and environmental protection.

[0005] In recent years, conventional kinetic hydrate inhibitors have received extensive attention. Conventional kinetic hydrate inhibitors inhibit hydrate nucleation or hinder the growth of crystal nuclei through the action of their own functional groups. Their characteristics are that the inhibition effect is significant at low dosages, but under high supercooling conditions, their inhibition time becomes very short, limiting their scope of use.

[0006] In order to improve the hydrate inhibition effect and the maximum supercooling degree, the Chinese patent document with the publication number CN111349194A discloses a fluorinated polyvinyl pyrrolidone natural gas hydrate inhibitor and its preparation method, which uses vinyl pyrrolidone monomer and perfluoroalkyl acrylate monomer to synthesize the hydrate inhibitor, but the perfluoroalkyl acrylate monomer is expensive, making the inhibitor cost high. The Chinese patent document with the publication number CN109764241A discloses a composite hydrate kinetic inhibitor based on vinyl imidazole copolymer and its application, the composite hydrate kinetic inhibitor of the vinyl imidazole copolymer has a maximum supercooling degree of 12.8°C, but its addition amount is large (2%), and the cost of the treatment agent is high.

[0007] Therefore, existing kinetic hydrate inhibitors have problems such as large dosage, poor inhibition effect, high overall cost and unsuitability for higher supercooling conditions. Summary of the invention

[0008] The present invention provides a natural gas hydrate kinetic inhibitor containing a polycyclic structure and a preparation method thereof, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of some kinetic hydrate inhibitors such as large dosage, poor inhibition effect, high comprehensive cost and unsuitability for higher supercooling conditions.

[0009] One of the technical solutions of the present invention is achieved by the following measures: a natural gas hydrate kinetic inhibitor containing a polycyclic structure, the structural formula of which is:

[0010]

[0011] Among them, x is 6 to 12, y is 4 to 16, and z is 4 to 8.

[0012] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions:

[0013] The above-mentioned natural gas hydrate kinetic inhibitor containing a polycyclic structure comprises, by weight, 20 to 60 parts of acryloylmorpholine, 10 to 40 parts of maleic anhydride, 30 to 60 parts of dimethylaminopropyl acrylamide, 60 to 120 parts of isohexanediol, 0.1 to 2 parts of initiator, 0.1 to 0.5 parts of chain transfer agent and 0.1 to 0.5 parts of chain terminator.

[0014] The initiator is a mixture of hydrogen peroxide and vitamin C or azobisisobutyronitrile, wherein the mass ratio of hydrogen peroxide to vitamin C in the mixture of hydrogen peroxide and vitamin C is 1 to 2:1.

[0015] The chain transfer agent is one of dodecyl mercaptan and thioglycolic acid.

[0016] The chain terminator is one of hydroquinone, p-tert-butylcatechol and acetone thiosemicarbazone.

[0017] The above-mentioned natural gas hydrate kinetic inhibitor containing a polycyclic structure is obtained by the following method:

[0018] S1, adding required amounts of maleic anhydride, acryloylmorpholine and dimethylaminopropylacrylamide to a required amount of isohexyl glycol in sequence under stirring to obtain a mixed solution;

[0019] S2, adding a required amount of initiator to the mixed solution to react to obtain an intermediate product 1;

[0020] S3, adding a required amount of chain transfer agent to the intermediate product 1 to continue the reaction to obtain the intermediate product 2;

[0021] S4, adding a required amount of chain terminator to the intermediate product 2 to react again to obtain a natural gas hydrate kinetic inhibitor containing a polycyclic structure.

[0022] In the above step S2, the reaction temperature is 40°C to 80°C, and the reaction time is 0.5h to 1.0h.

[0023] In the above step S3, the reaction time is 2 h to 8 h, and in step S4, the reaction time is 0.5 h to 2.0 h.

[0024] The second technical solution of the present invention is achieved by the following measures: A method for preparing a natural gas hydrate kinetic inhibitor containing a polycyclic structure is carried out according to the following method:

[0025] S1, adding required amounts of maleic anhydride, acryloylmorpholine and dimethylaminopropylacrylamide to a required amount of isohexyl glycol in sequence under stirring to obtain a mixed solution;

[0026] S2, adding a required amount of initiator to the mixed solution to react to obtain an intermediate product 1;

[0027] S3, adding a required amount of chain transfer agent to the intermediate product 1 to continue the reaction to obtain the intermediate product 2;

[0028] S4, adding a required amount of chain terminator to the intermediate product 2 to react again to obtain a natural gas hydrate kinetic inhibitor containing a polycyclic structure.

[0029] The natural gas hydrate kinetic inhibitor containing a polycyclic structure of the present invention is a kinetic inhibitor. The natural gas hydrate kinetic inhibitor containing a polycyclic structure of the present invention is added during the natural gas injection, production and gathering and transportation process. The unique polycyclic rings can participate in the formation of hydrate crystal structures, effectively inhibit the growth of hydrate crystals, and prevent the formation of large-particle hydrates. It has the advantages of good inhibition effect, small dosage, and low comprehensive cost. At the same time, it can expand the application range of supercooling. DETAILED DESCRIPTION

[0030] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals known and used in the prior art; unless otherwise specified, the percentages in the present invention are all mass percentages; unless otherwise specified, the solutions in the present invention are all aqueous solutions with water as the solvent, for example, hydrochloric acid solution is a hydrochloric acid aqueous solution; the normal temperature and room temperature in the present invention generally refer to a temperature of 15°C to 25°C, and are generally defined as 25°C.

[0031] The present invention will be further described below in conjunction with embodiments:

[0032] Example 1: The natural gas hydrate kinetic inhibitor containing a polycyclic structure has the structural formula:

[0033]

[0034] Among them, x is 6 to 12, y is 4 to 16, and z is 4 to 8.

[0035] Example 2: The natural gas hydrate kinetic inhibitor containing a polycyclic structure comprises raw materials, by weight, including 20 to 60 parts of acryloylmorpholine, 10 to 40 parts of maleic anhydride, 30 to 60 parts of dimethylaminopropyl acrylamide, 60 to 120 parts of isohexanediol, 0.1 to 2 parts of initiator, 0.1 to 0.5 parts of chain transfer agent and 0.1 to 0.5 parts of chain terminator.

[0036] Example 3: As an optimization of the above example, the initiator is a mixture of hydrogen peroxide and vitamin C or azobisisobutyronitrile, wherein the mass ratio of hydrogen peroxide to vitamin C in the mixture of hydrogen peroxide and vitamin C is 1 to 2:1.

[0037] Example 4: As an optimization of the above example, the chain transfer agent is one of dodecyl mercaptan and thioglycolic acid.

[0038] Example 5: As an optimization of the above example, the chain terminator is one of hydroquinone, p-tert-butylcatechol and acetone thiosemicarbazone.

[0039] Example 6: As an optimization of the above example, a natural gas hydrate kinetic inhibitor containing a polycyclic structure is obtained by the following method:

[0040] S1, adding required amounts of maleic anhydride, acryloylmorpholine and dimethylaminopropylacrylamide to a required amount of isohexyl glycol in sequence under stirring to obtain a mixed solution;

[0041] S2, adding a required amount of initiator to the mixed solution to react to obtain an intermediate product 1;

[0042] S3, adding a required amount of chain transfer agent to the intermediate product 1 to continue the reaction to obtain the intermediate product 2;

[0043] S4, adding a required amount of chain terminator to the intermediate product 2 to react again to obtain a natural gas hydrate kinetic inhibitor containing a polycyclic structure.

[0044] Example 7: As an optimization of the above example, in step S2, the reaction temperature is 40°C to 80°C, and the reaction time is 0.5h to 1.0h.

[0045] Example 8: As an optimization of the above example, in step S3, the reaction time is 2 h to 8 h, and in step S4, the reaction time is 0.5 h to 2.0 h.

[0046] Embodiment 9:

[0047] The natural gas hydrate kinetic inhibitor containing a polycyclic structure comprises raw materials, by weight, including 20 parts of acryloylmorpholine, 10 parts of maleic anhydride, 30 parts of dimethylaminopropyl acrylamide, 60 parts of isohexanediol, 0.1 part of initiator (azobisisobutyronitrile), 0.1 part of chain transfer agent (dodecyl mercaptan) and 0.1 part of chain terminator (hydroquinone), and is obtained by the following method:

[0048] S1, adding required amounts of maleic anhydride, acryloylmorpholine and dimethylaminopropylacrylamide to a required amount of isohexyl glycol in sequence under stirring to obtain a mixed solution;

[0049] S2, add the required amount of initiator to the mixed solution, react at 40°C for 0.5h, and obtain intermediate product 1;

[0050] S3, adding a required amount of chain transfer agent to the intermediate product 1 and continuing the reaction for 2 hours to obtain the intermediate product 2;

[0051] S4, adding a required amount of chain terminator to the intermediate product 2 and reacting again for 0.5h to obtain a natural gas hydrate kinetic inhibitor containing a polycyclic structure.

[0052] Embodiment 10:

[0053] The natural gas hydrate kinetic inhibitor containing a polycyclic structure comprises, by weight, 60 parts of acryloylmorpholine, 40 parts of maleic anhydride, 60 parts of dimethylaminopropyl acrylamide, 120 parts of isohexyl glycol, 2 parts of an initiator (a mixture of hydrogen peroxide and vitamin C in a mass ratio of 1:1), 0.5 parts of a chain transfer agent (thioglycolic acid) and 0.5 parts of a chain terminator (p-tert-butylcatechol), and is obtained by the following method:

[0054] S1, adding required amounts of maleic anhydride, acryloylmorpholine and dimethylaminopropylacrylamide to a required amount of isohexyl glycol in sequence under stirring to obtain a mixed solution;

[0055] S2, adding a required amount of initiator to the mixed solution, reacting at 80°C for 1.0h to obtain an intermediate product 1;

[0056] S3, adding a required amount of chain transfer agent to the intermediate product 1 and continuing the reaction for 8 hours to obtain the intermediate product 2;

[0057] S4, adding a required amount of chain terminator to the intermediate product 2 and reacting again for 2.0 hours to obtain a natural gas hydrate kinetic inhibitor containing a polycyclic structure.

[0058] Embodiment 11:

[0059] The natural gas hydrate kinetic inhibitor containing a polycyclic structure comprises raw materials, by weight, including 40 parts of acryloylmorpholine, 20 parts of maleic anhydride, 45 parts of dimethylaminopropyl acrylamide, 80 parts of isohexanediol, 1 part of initiator (azobisisobutyronitrile), 0.3 parts of chain transfer agent (dodecyl mercaptan) and 0.3 parts of chain terminator (acetone thiosemicarbazone), and is obtained by the following method:

[0060] S1, adding required amounts of maleic anhydride, acryloylmorpholine and dimethylaminopropylacrylamide to a required amount of isohexyl glycol in sequence under stirring to obtain a mixed solution;

[0061] S2, adding a required amount of initiator to the mixed solution, reacting at 60°C for 0.8h to obtain an intermediate product 1;

[0062] S3, adding a required amount of chain transfer agent to the intermediate product 1 and continuing the reaction for 6 hours to obtain the intermediate product 2;

[0063] S4, adding a required amount of chain terminator to the intermediate product 2 and reacting again for 1 hour to obtain a natural gas hydrate kinetic inhibitor containing a polycyclic structure.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] The natural gas hydrate kinetic inhibitor containing a polycyclic structure of the present invention is a kinetic inhibitor. The natural gas hydrate kinetic inhibitor containing a polycyclic structure of the present invention is added during the natural gas injection, production and gathering and transportation process. The unique polycyclic rings can participate in the formation of hydrate crystal structures, effectively inhibit the growth of hydrate crystals, and prevent the formation of large-particle hydrates. It has the advantages of good inhibition effect, small dosage, and low comprehensive cost. At the same time, it can expand the application range of supercooling.

[0066] Embodiment 12:

[0067] The natural gas hydrate kinetic inhibitor containing a polycyclic structure is obtained by the following method:

[0068] S1, under stirring, add 10 g of maleic anhydride to 90 g of isohexyl glycol, stir and dissolve, then add 40 g of acryloylmorpholine and 40 g of dimethylaminopropyl acrylamide to obtain a mixed solution;

[0069] S2, add 1 g of initiator (azobisisobutyronitrile) dropwise to the mixed solution, react at 70°C for 0.5 h, and obtain intermediate product 1;

[0070] S3, adding 0.5 g of chain transfer agent (dodecyl mercaptan) to the intermediate product 1 and continuing the reaction for 5 h to obtain the intermediate product 2;

[0071] S4, adding 0.2 g of chain terminator (p-tert-butylcatechol) to the intermediate product 2 and reacting again for 1 hour to obtain a natural gas hydrate kinetic inhibitor containing a polycyclic structure.

[0072] Embodiment 13:

[0073] The natural gas hydrate kinetic inhibitor containing a polycyclic structure is obtained by the following method:

[0074] S1, under stirring, add 20 g of maleic anhydride to 90 g of isohexyl glycol, stir and dissolve, then add 40 g of acryloylmorpholine and 30 g of dimethylaminopropyl acrylamide to obtain a mixed solution;

[0075] S2, add 1 g of initiator (0.5 g of hydrogen peroxide and 0.5 g of vitamin C) to the mixed solution, react at 60° C. for 0.5 h, and obtain intermediate product 1;

[0076] S3, adding 0.5 g of chain transfer agent (thioglycolic acid) to the intermediate product 1 and continuing the reaction for 3 h to obtain the intermediate product 2;

[0077] S4, adding 0.2 g of chain terminator (acetone thiosemicarbazone) to the intermediate product 2 and reacting again for 1 h to obtain a natural gas hydrate kinetic inhibitor containing a polycyclic structure.

[0078] Embodiment 14:

[0079] The natural gas hydrate kinetic inhibitor containing a polycyclic structure is obtained by the following method:

[0080] S1, under stirring, add 20 g of maleic anhydride to 120 g of isohexyl glycol in sequence, stir and dissolve, then add 50 g of acryloylmorpholine and 50 g of dimethylaminopropyl acrylamide to obtain a mixed solution;

[0081] S2, add 1 g of initiator (0.5 g of hydrogen peroxide and 0.5 g of vitamin C) to the mixed solution, react at 80° C. for 0.5 h, and obtain intermediate product 1;

[0082] S3, adding 1 g of chain transfer agent (dodecyl mercaptan) to the intermediate product 1 and continuing the reaction for 6 h to obtain the intermediate product 2;

[0083] S4, adding 0.3 g of chain terminator (hydroquinone) to the intermediate product 2 and reacting again for 2 h to obtain a natural gas hydrate kinetic inhibitor containing a polycyclic structure.

[0084] Example 15: A low-temperature autoclave device was used to evaluate the inhibitory effect of the natural gas hydrate kinetic inhibitor containing a polycyclic structure of the present invention, and the inhibitory effect indexes examined included the inhibition time (min) and the maximum supercooling degree (°C). The test method is as follows:

[0085] Inhibition time: First, the reactor was cleaned with distilled water and the cleaning liquid was discharged. Then, a 0.5% aqueous solution of the natural gas hydrate kinetic inhibitor containing a polycyclic structure of the present invention was pumped in, and the air in the reactor was evacuated with a vacuum pump. The temperature was lowered to 4°C, and methane gas was introduced. The pressure in the reactor was adjusted to the experimental pressure of 15 MPa. The gas inlet valve of the reactor was closed, and stirring was started at a speed of 1000 r / min. Finally, the pressure and temperature data in the reactor were monitored and collected. Before hydrates were generated, the temperature and pressure in the reactor were stable. When hydrates were generated, the pressure dropped sharply and the temperature increased accordingly. The hydrate inhibition time can be determined.

[0086] Maximum supercooling: First, the reactor is cleaned with distilled water and the cleaning liquid is discharged; then, a 0.5% concentration of the natural gas hydrate kinetic inhibitor aqueous solution containing a polycyclic structure of the present invention is pumped in, and the air in the reactor is evacuated with a vacuum pump, and then methane gas is introduced, and the pressure in the reactor is adjusted to the experimental pressure of 15MPa, the gas inlet valve of the reactor is closed, stirring is started, the speed is 1000r / min, and the reactor is cooled from 20°C to -10°C at a constant cooling rate of 1°C / h to induce hydrate formation. Finally, the pressure and temperature data in the reactor are monitored and collected. Before the formation of hydrates, the temperature and pressure in the reactor are reduced at a constant rate. When hydrates are generated, the pressure will drop sharply and the temperature will rise accordingly. The rapid drop in pressure in the curve indicates that hydrates begin to form, and the hydrate initial formation temperature (the sharp pressure drop inflection point occurs). The maximum supercooling is the difference between the hydrate critical temperature corresponding to the pressure at this time and the hydrate initial formation temperature.

[0087] The inhibitory effects of the natural gas hydrate kinetic inhibitors containing a polycyclic structure prepared in Examples 12 to 14 of the present invention were evaluated according to the above-mentioned test method. At the same time, conventional kinetic inhibitors polyvinyl pyrrolidone or poly-N-vinyl caprolactam were used as controls. The test results are shown in Table 1. As can be seen from Table 1, compared with conventional kinetic inhibitors polyvinyl pyrrolidone or poly-N-vinyl caprolactam, the natural gas hydrate kinetic inhibitors containing a polycyclic structure prepared in Examples 12 to 14 of the present invention can effectively prolong the hydrate formation time and increase the maximum supercooling degree, and have excellent inhibitory performance.

[0088] In summary, the natural gas hydrate kinetic inhibitor containing a polycyclic structure of the present invention is a kinetic inhibitor. When the natural gas hydrate kinetic inhibitor containing a polycyclic structure of the present invention is added during the natural gas injection, production and gathering and transportation process, it can participate in the formation of the hydrate crystal structure through its unique polycyclic rings, effectively inhibit the growth of hydrate crystals, and prevent the formation of large-particle hydrates. It has the advantages of good inhibitory effect, small dosage, and low comprehensive cost. At the same time, it can expand the applicable range of supercooling.

[0089] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

[0090] Table 1

[0091] name Hydrate inhibition time, min Distilled water 20 Distilled water + 0.5% Example 12 2880 Distilled water + 0.5% Example 13 2520 Distilled water + 0.5% Example 14 5520 Distilled water + 0.5% polyvinylpyrrolidone 720 Distilled water + 0.5% poly N-vinyl caprolactam 1600

[0092] Table 2

[0093] name Maximum subcooling, ℃ Distilled water 2.9 Distilled water + 0.5% Example 12 13.5 Distilled water + 0.5% Example 13 12.8 Distilled water + 0.5% Example 14 14.3 Distilled water + 0.5% polyvinylpyrrolidone 5.6 Distilled water + 0.5% poly N-vinyl caprolactam 9.2

Claims

1. A natural gas hydrate kinetic inhibitor containing a polycyclic structure, characterized in that Its structural formula is: Among them, x is 6 to 12, y is 4 to 16, and z is 4 to 8.

2. The natural gas hydrate kinetic inhibitor containing a polycyclic structure according to claim 1, characterized in that The raw materials include, by weight, 20 to 60 parts of acryloylmorpholine, 10 to 40 parts of maleic anhydride, 30 to 60 parts of dimethylaminopropyl acrylamide, 60 to 120 parts of isohexanediol, 0.1 to 2 parts of initiator, 0.1 to 0.5 parts of chain transfer agent and 0.1 to 0.5 parts of chain terminator.

3. The natural gas hydrate kinetic inhibitor containing a polycyclic structure according to claim 2, characterized in that The initiator is a mixture of hydrogen peroxide and vitamin C or azobisisobutyronitrile, wherein the mass ratio of hydrogen peroxide to vitamin C in the mixture of hydrogen peroxide and vitamin C is 1 to 2:

1.

4. The natural gas hydrate kinetic inhibitor containing a polycyclic structure according to claim 2 or 3, characterized in that The chain transfer agent is one of dodecyl mercaptan and thioglycolic acid.

5. The natural gas hydrate kinetic inhibitor containing a polycyclic structure according to claim 2, 3 or 4, characterized in that The chain terminator is one of hydroquinone, p-tert-butylcatechol and acetone thiosemicarbazone.

6. The natural gas hydrate kinetic inhibitor containing a polycyclic structure according to any one of claims 1 to 5, characterized in that Obtained as follows: S1, adding required amounts of maleic anhydride, acryloylmorpholine and dimethylaminopropylacrylamide to a required amount of isohexyl glycol in sequence under stirring to obtain a mixed solution; S2, adding a required amount of initiator to the mixed solution to react to obtain an intermediate product 1; S3, adding a required amount of chain transfer agent to the intermediate product 1 to continue the reaction to obtain the intermediate product 2; S4, adding a required amount of chain terminator to the intermediate product 2 to react again to obtain a natural gas hydrate kinetic inhibitor containing a polycyclic structure.

7. The natural gas hydrate kinetic inhibitor containing a polycyclic structure according to claim 6, characterized in that In step S2, the reaction temperature is 40°C to 80°C, and the reaction time is 0.5h to 1.0h.

8. The natural gas hydrate kinetic inhibitor containing a polycyclic structure according to claim 6 or 7, characterized in that In step S3, the reaction time is 2 h to 8 h, and in step S4, the reaction time is 0.5 h to 2.0 h.

9. A method for preparing a natural gas hydrate kinetic inhibitor containing a polycyclic structure according to claims 1 to 5, 7 to 8, characterized in that Proceed as follows: S1, adding required amounts of maleic anhydride, acryloylmorpholine and dimethylaminopropylacrylamide to a required amount of isohexyl glycol in sequence under stirring to obtain a mixed solution; S2, adding a required amount of initiator to the mixed solution to react to obtain an intermediate product 1; S3, adding a required amount of chain transfer agent to the intermediate product 1 to continue the reaction to obtain the intermediate product 2; S4, adding a required amount of chain terminator to the intermediate product 2 to react again to obtain a natural gas hydrate kinetic inhibitor containing a polycyclic structure.

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