A high-temperature resistant and salt-resistant crosslinked hydrophobic polymer, its preparation method and application

Abstract

This invention provides a high-temperature and salt-resistant crosslinked hydrophobic polymer, belonging to the field of hydrophobic polymer technology. The polymer is obtained by copolymerization of 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomers, divinyl monomers, and fluorinated short-chain acrylates; the mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomers, divinyl monomers, and fluorinated short-chain acrylates is 20:(5-8):(0.5-2):(3-5). The high-temperature and salt-resistant crosslinked hydrophobic polymer of this invention contains vinyl polycyclic structural units and fluorinated groups that can inhibit the thermal degradation of acrylamide under high-temperature conditions. Furthermore, the molecule does not contain easily degradable functional groups such as esters and ethers at high temperatures, thus exhibiting excellent temperature resistance, and its aqueous solution viscosity remains stable for a long time under high-temperature conditions.

Description

Technical Field

[0001] This invention belongs to the field of hydrophobic polymer technology, specifically relating to a high-temperature and salt-resistant crosslinked hydrophobic polymer, its preparation method, and its application. Background Technology

[0002] As oil and gas exploration and development gradually extends to deeper formations and offshore areas, the geological formations encountered are becoming increasingly complex, including high-temperature, high-salt, and salt-gypsum layers. To ensure the safe and smooth progress of drilling operations, higher demands are placed on drilling fluids and treatment agents. Among these, viscosifiers used to adjust the rheological properties of drilling fluids are crucial. Commonly used polymer viscosifiers are prone to degradation under high-temperature conditions, and their viscosifying effect decreases significantly when encountering saline formations, making them unsuitable for carrying suspended cuttings. Currently, the drilling fluid viscosifiers used domestically are mostly modified fibers, modified guar gum, xanthan gum, and acrylamide polymers. While these viscosifiers have advantages in some aspects, most suffer from insufficient temperature and salt resistance, or insignificant viscosifying effects. Currently, high-temperature well sections mainly rely on imported viscosifier products. Therefore, it is necessary to develop a drilling fluid viscosifier with good temperature and salt resistance to meet the needs of deep well drilling.

[0003] In existing technologies, synthetic polymer-based thickeners exhibit significantly improved temperature and salt resistance due to the introduction of various functional groups. For example, patent CN 201010172382.8 discloses a method for preparing a high-temperature and salt-resistant thickener for drilling fluids. Its main components are 2-acrylamido-2-methylpropanesulfonic acid, acrylamide, and acrylic acid copolymer. In slurries with a salt concentration of 30% or higher at 180°C, the cuttings rolling recovery rate is >90%, but it does not mention the thickening and filtration loss reduction effects. Patent CN 201310061721.9 discloses a drilling fluid thickener and its preparation method. This thickener is polymerized from water-soluble monomers and hydrophobic monomers of different ionic types. It exhibits good thickening properties at 260°C, but the drilling fluid shear strength is low after high-temperature aging, and its salt resistance is not mentioned. Patent CN 201610681472.7 discloses a temperature- and salt-resistant viscosity improver for drilling fluids, its preparation method, and its application. It is synthesized by the internal polymerization of acrylamide, N-vinylpyrrolidone, and 4-vinyl-1-(3-sulfopropyl)pyridine. In a high-concentration composite brine solution composed of 3% calcium chloride, 3% magnesium chloride, and 5%-20% sodium chloride at 180°C, it maintains good viscosity. US Patent US7651980B2 discloses a terpolymer composed of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and N-vinylpyrrolidone, its preparation method, and its application. This copolymer can withstand temperatures up to 260°C as a drilling fluid viscosity improver, but this is limited to freshwater drilling fluids and does not address the evaluation of its viscosity-improving effect when the sodium and calcium salt content in the drilling fluid is high. Summary of the Invention

[0004] To address the problems in existing technologies, this invention provides a high-temperature and salt-resistant crosslinked hydrophobic polymer, its preparation method, and its applications. The high-temperature and salt-resistant crosslinked hydrophobic polymer of this invention contains vinyl polycyclic ring structural units and fluorinated groups that can inhibit the thermal degradation of acrylamide under high-temperature conditions. Furthermore, the molecule does not contain easily degradable functional groups such as esters and ethers at high temperatures, thus exhibiting excellent temperature resistance. Its aqueous solution viscosity remains stable for extended periods under high-temperature conditions.

[0005] According to one aspect of the present invention, a high-temperature resistant and salt-resistant crosslinked hydrophobic polymer is provided, said polymer being obtained by copolymerization of raw materials comprising 2-acrylamido-2-methylpropanesulfonic acid (AMPS), alkenyl polycyclic monomers, divinyl monomers and fluorinated short-chain acrylates;

[0006] The mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomer, divinyl monomer and fluorinated short-chain acrylate is 20:(5-8):(0.5-2):(3-5).

[0007] Optionally, the alkenyl polycyclic monomer is selected from any one of 1-vinyl-2-pyrrolidone (N-vinylpyrrolidone), 5-vinyl-2-pyrrolidone, and 4-vinylpyridine.

[0008] Optionally, the divinyl monomer is selected from any one of divinylbenzene, 2,4-divinylpyridine, divinylbiphenyl, and divinyl sulfone.

[0009] Optionally, the fluorinated short-chain acrylate is selected from any one of trifluoroethyl methacrylate, hexafluorobutyl methacrylate, and dodecafluoroheptyl methacrylate.

[0010] Optionally, the number-average molecular weight of the polymer is 1.5 million to 2.2 million.

[0011] According to another aspect of the present invention, a method for preparing the above-mentioned polymer is provided, comprising the following steps:

[0012] (1) Prepare an aqueous solution containing 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomers, divinyl monomers, fluorinated short-chain acrylates and surfactants;

[0013] (2) Adjust the pH of the aqueous solution, introduce nitrogen gas, and keep it warm;

[0014] (3) Under nitrogen atmosphere protection, add initiator, stir, react, and obtain viscous glue solution;

[0015] (4) The viscous liquid is dried, crushed, and sieved to obtain the polymer.

[0016] Optionally, in step (2), sodium hydroxide is used to adjust the pH of the solution to 7-10.

[0017] Optionally, in step (2), the temperature of the heat preservation is 10 to 30°C and the time is 0.5 to 1 hour.

[0018] Optionally, in step (3), the stirring speed is 600 r / min to 1200 r / min.

[0019] Optionally, in step (3), the reaction temperature is 50-80°C and the time is 3-8 hours.

[0020] Optionally, in step (4), the viscous adhesive is dried at 100°C to 105°C until the moisture content is less than 10%.

[0021] Optionally, in step (4), the mesh size of the pulverized material is 200 to 400 mesh.

[0022] Optionally, the surfactant is sodium dodecyl sulfate (SDS).

[0023] Optionally, the surfactant is 0.5 to 2.0 times the mass of the total monomers, wherein the total monomers include 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomers, divinyl monomers, and fluorinated short-chain acrylates.

[0024] Optionally, the initiator is selected from one of azobisisobutyronitrile and azobisisoheptanenitrile.

[0025] Optionally, the initiator is 0.3 to 1.0 times the mass of the total monomers, which include 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomers, divinyl monomers, and fluorinated short-chain acrylates.

[0026] Optionally, in the aqueous solution, the mass of water is 1.5 to 4 times the mass of the total monomers, wherein the total monomers include 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomers, divinyl monomers, and fluorinated short-chain acrylates.

[0027] According to another aspect of the present invention, the application of the above-described polymer and the polymer prepared by the above-described method in a thickener for drilling fluids is provided.

[0028] One specific embodiment of the present invention provides a method for preparing a high-temperature resistant and salt-resistant crosslinked hydrophobic polymer, comprising the following steps:

[0029] (1) Add deionized water, 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomer, divinyl monomer, fluorinated short-chain acrylate and sodium dodecyl sulfate to the reaction vessel, stir evenly to form a solution;

[0030] (2) Adjust the pH of the solution to 7-10 with sodium hydroxide and introduce nitrogen gas to reduce the temperature inside the reactor to 10-30℃;

[0031] (3) After 0.5 to 1 hour, under the protection of nitrogen atmosphere, a certain amount of initiator is added, and the reaction temperature is gradually increased to 50 to 80°C under the condition of stirring speed of 800 r / min. The reaction is carried out for 5 hours and then cooled to room temperature to obtain a viscous liquid.

[0032] (4) The viscous liquid is placed in an oven and heated to dry, then crushed and sieved to obtain the high-temperature resistant and salt-resistant crosslinked hydrophobic polymer.

[0033] The present invention has the following beneficial effects:

[0034] (1) The high temperature and salt resistant hydrophobic polymer provided by the present invention has good temperature and salt resistance. Even at a temperature of up to 200℃, it still has good thickening properties and can resist 30% NaCl. At the same time, it can effectively reduce the filtration loss of drilling fluid.

[0035] (2) The polymer of the present invention uses CC chain as main chain and crosslinking agent to branch or crosslink the molecular chain, so that the tackifier molecules form a branched or three-dimensional polymer with a certain network structure in the secondary structure, thereby enhancing the temperature resistance.

[0036] (3) The sulfonic acid groups on the polymer molecule not only improve the water solubility of the thickener, but also have a high charge density and strong hydration ability. Their special charge distribution structure makes the sulfonic acid groups insensitive to the attack of external cations, thereby enhancing the polymer's resistance to salt and calcium. The amide groups on the molecule can be firmly adsorbed to clay particles through electrostatic attraction and van der Waals forces, effectively improving the thickening effect of the polymer.

[0037] (4) The polymer molecular backbone has added benzene rings and multi-ring structures, which enhances the rigidity of the molecules, optimizes the hydrophilic and hydrophobic properties of the molecular chains, adjusts the degree of shrinkage and viscosity changes of polymer molecules at medium and high temperatures, improves the effect of hydrogen bonds and ionic bonds between polymer molecules and between polymer molecules and other substances, and weakens the high-temperature desorption caused by thermal motion of molecules. Therefore, the polymer itself has a strong temperature and salt resistance. At the same time, the strong adsorption of the rigid groups of the polymer can ensure that the polymer and clay have a good adsorption effect at high temperatures, which improves its salt resistance and ensures that the polymer still has a good viscosity effect at high temperatures.

[0038] (5) Fluorinated short-chain acrylates possess excellent heat and chemical stability, extremely low surface energy, superior hydrophobicity and oleophobicity, and good film-forming ability. Introducing a certain amount of fluorinated short-chain acrylates into the polymer can not only improve the rigidity of the molecular chain and provide hydrophobic shielding, thus enhancing the product's resistance to hydrolysis and degradation, but also improve the film strength of the drilling fluid cake, giving it better hydrophobic and oleophobic effects and reducing the rate at which the filtrate penetrates the formation. Detailed Implementation

[0039] In this embodiment of the invention, the viscosity of the high-temperature resistant, salt-resistant, and hydrophobic polymer aqueous solution is measured using a ZNN-D6 electric six-speed rotary viscometer manufactured by Qingdao Haitongda Special Instrument Factory. The filtration loss is measured using an SD-3 medium-pressure filtration loss meter manufactured by Qingdao Haitongda Special Instrument Factory.

[0040] The specific information of the reagents used in the various embodiments of the present invention is as follows:

[0041] Divinylbenzene was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0042] 2-Acrylamido-2-methylpropanesulfonic acid, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0043] N-vinylpyrrolidone, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0044] 5-Vinyl-2-pyrrolidone, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0045] Trifluoroethyl acrylate, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0046] Sodium dodecyl sulfate (SDS) was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0047] N-Vinylcaprolactam, purchased from Shanghai Yuanye Biotechnology Co., Ltd.;

[0048] 2,4-Divinylpyridine was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0049] Hexafluorobutyl methacrylate, purchased from Jinan Guochen Taifu Chemical Co., Ltd.

[0050] Azobisisobutyronitrile, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0051] Divinylbiphenyl, purchased from Hubei Yongkuo Technology Co., Ltd.;

[0052] Dodecafluoroheptyl methacrylate, purchased from Zhengzhou Alpha Chemical Co., Ltd.;

[0053] Divinyl sulfone, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0054] Trifluoroethyl methacrylate was purchased from Jinan Guochen Taifu Chemical Co., Ltd.

[0055] Example 1

[0056] (1) Add 50g of deionized water, 20g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 5g of N-vinylpyrrolidone, 0.5g of divinylbenzene, 3g of trifluoroethyl methacrylate, and 0.5g of sodium dodecyl sulfate (SDS) to the reaction vessel and stir until a solution is formed.

[0057] (2) Adjust the pH of the solution to 7 with sodium hydroxide and introduce nitrogen gas to raise the temperature of the reactor to 30°C.

[0058] (3) After 0.5 hours, under nitrogen atmosphere protection, 0.3 g of azobisisobutyronitrile was added. The reaction temperature was gradually increased to 50°C under stirring speed of 600 r / min. The reaction was carried out for 3 hours and then cooled to room temperature to obtain a viscous liquid.

[0059] (4) The viscous liquid is placed in an oven at 105°C and heated to dry, then pulverized to 200 mesh and sieved to obtain the high-temperature resistant and salt-resistant crosslinked hydrophobic polymer.

[0060] Example 2

[0061] (1) Add 60g of deionized water, 20g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 8g of 5-vinyl-2-pyrrolidone, 1.0g of 2,4-divinylpyridine, 4g of hexafluorobutyl methacrylate, and 1.5g of sodium dodecyl sulfate (SDS) to the reaction vessel and stir until a solution is formed.

[0062] (2) Adjust the pH of the solution to 8 with sodium hydroxide and introduce nitrogen gas to raise the temperature of the reactor to 20°C.

[0063] (3) After 0.8 hours, under nitrogen atmosphere protection, 0.8 g of azobisisoheptanenitrile was added. The reaction temperature was gradually increased to 60°C under stirring speed of 800 r / min. The reaction was carried out for 5 hours and then cooled to room temperature to obtain a viscous liquid.

[0064] (4) The viscous liquid is placed in an oven at 105°C and heated to dry, then pulverized to 300 mesh and sieved to obtain the high-temperature resistant and salt-resistant crosslinked hydrophobic polymer.

[0065] Example 3

[0066] (1) Add 80g of deionized water, 20g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 6g of N-vinylpyrrolidone, 1.5g of divinylbiphenyl, 5g of dodecylfluoroheptyl methacrylate, and 1.0g of sodium dodecyl sulfate (SDS) to the reaction vessel and stir until a solution is formed.

[0067] (2) Adjust the pH of the solution to 9 with sodium hydroxide and introduce nitrogen gas to raise the temperature of the reactor to 20°C.

[0068] (3) After 1 hour, under nitrogen atmosphere protection, 0.5 g of azobisisobutyronitrile was added. Under the condition of stirring speed of 1000 r / min, the reaction temperature was gradually increased to 80℃ and reacted for 6 hours. After cooling to room temperature, a viscous liquid was obtained.

[0069] (4) The viscous liquid is placed in an oven at 105°C and heated to dry, then pulverized to 400 mesh and sieved to obtain the high-temperature resistant and salt-resistant crosslinked hydrophobic polymer.

[0070] Example 4

[0071] (1) Add 100g of deionized water, 20g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 7g of N-vinylpyrrolidone, 2g of divinyl sulfone, 4g of trifluoroethyl methacrylate, and 2g of sodium dodecyl sulfate (SDS) to the reaction vessel and stir until a solution is formed.

[0072] (2) Adjust the pH of the solution to 10 with sodium hydroxide and introduce nitrogen gas to lower the temperature of the reactor to 10°C.

[0073] (3) After 1 hour, under nitrogen atmosphere protection, 1.0 g of azobisisobutyronitrile was added. Under the condition of stirring speed of 1200 r / min, the reaction temperature was gradually increased to 70℃ and reacted for 6 hours. After cooling to room temperature, a viscous liquid was obtained.

[0074] (4) The viscous liquid is placed in an oven at 105°C and heated to dry, then pulverized to 300 mesh and sieved to obtain the high-temperature resistant and salt-resistant crosslinked hydrophobic polymer.

[0075] Comparative Example 1

[0076] The difference between Comparative Example 1 and Example 2 is that 4g of hexafluorobutyl methacrylate in step (1) is removed, while other conditions remain unchanged.

[0077] Comparative Example 2

[0078] The difference between Comparative Example 1 and Example 2 is that 1.0 g of 2,4-divinylpyridine was removed in step (1), while other conditions remained unchanged.

[0079] Comparative Example 3

[0080] The difference between Comparative Example 1 and Example 2 is that the amount of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) in step (1) is increased from 20g to 50g, while other conditions remain unchanged.

[0081] Comparative Example 4

[0082] The difference between Comparative Example 1 and Example 2 is that the reaction temperature in step (3) is increased from 60°C to 90°C, while other conditions remain unchanged.

[0083] Test case

[0084] The performance of the high-temperature resistant, salt-resistant, and hydrophobic polymers prepared in Examples 1-4 and Comparative Examples 1-4 was evaluated.

[0085] 1. Temperature and NaCl resistance

[0086] The evaluation method for the temperature and salt resistance of the polymer in the embodiments of the present invention is as follows: (1) First, prepare an aqueous solution containing 30% sodium chloride concentration, and then add 2% of the copolymer described in the present invention and 2% anhydrous sodium sulfite to the salt solution under stirring until the copolymer is completely dissolved; (2) At room temperature, use a ZNN-D6 type electric six-speed rotational viscometer to measure the viscosity and shear force of the solution; after the measurement, transfer the polymer solution to an XGRL-4A type high temperature roller furnace produced by Qingdao Haitongda Special Instrument Factory, age it at 200℃ for 16 hours, and then cool it to room temperature; (3) At room temperature, measure the viscosity and shear force of the polymer solution after aging treatment, compare the changes in viscosity and shear force of the polymer solution before and after aging, and use the changes in solution viscosity and shear force as indicators for evaluating the temperature and salt resistance of the copolymer.

[0087] Table 1. Changes in polymer properties before and after aging at 200℃ in 30% NaCl solution.

[0088]

[0089]

[0090] Blank test: This is Example 2 under conditions without salt, i.e., water + 2% of the copolymer described in this invention + 2% Na2SO3.

[0091] As shown in Table 1, the high-temperature and salt-resistant hydrophobic polymers developed in Examples 1-4 maintained good viscosity and shear strength in a 30% NaCl aqueous solution. After aging at 200℃ for 16 hours, the viscosity and shear strength did not change significantly, indicating that the high-temperature and salt-resistant hydrophobic polymers provided by this invention have good temperature and salt resistance, and their aqueous solution viscosity and shear strength can remain stable for a long time under high-temperature conditions. In contrast, Comparative Example 1 lacked fluorinated short-chain acrylate monomers, resulting in a significant decrease in viscosity and shear strength after aging, indicating weaker temperature resistance. Comparative Example 2 lacked diethylene monomers that play a crosslinking role, and the resulting polymer could not form an uncrosslinked network structure, resulting in lower viscosity and shear strength, and poorer temperature resistance. Comparative Example 3 had a high content of 2-acrylamido-2-methylpropanesulfonic acid (AMPS). Due to the strong water solubility of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), an excessively high content affected the dispersion of other monomers, leading to incomplete polymerization and resulting in a product with low viscosity and shear strength. In Comparative Example 4, the polymerization temperature was too high, resulting in a violent polymerization reaction, an incomplete network structure, and low product viscosity.

[0092] 2. Filtration loss reduction performance

[0093] The evaluation method for polymer filtration loss reduction in this invention is as follows: (1) Add 2% of the copolymer described in this invention and 2% anhydrous sodium sulfite to 4% prehydrated bentonite slurry, and stir until the copolymer is completely dissolved to form a drilling fluid system; (2) Measure the filtration loss of the drilling fluid system using an SD-3 medium-pressure filtration loss meter at room temperature; after the measurement, transfer the drilling fluid system to an XGRL-4A high-temperature roller furnace produced by Qingdao Haitongda Special Instrument Factory, and age it at 200℃ for 16 hours, and then bring it to room temperature; (3) Measure the filtration loss of the aged drilling fluid system at room temperature, compare the changes in the filtrate volume of the drilling fluid system before and after aging, and use the change in filtrate volume as an indicator for evaluating the filtration loss reduction of the polymer.

[0094] Table 2. Changes in filtration loss of polymers in 4% pre-bentonite before and after aging at 200℃

[0095]

[0096]

[0097] Blank test: without polymer, i.e.: 4% pre-bentonite slurry + 1% copolymer of the present invention.

[0098] +2% Na2SO3.

[0099] As shown in Table 2, the high-temperature resistant, salt-resistant, and hydrophobic polymers developed in Examples 1-4 can effectively reduce the filtration loss in 4% of the pre-bentonite slurry. After aging at 200°C for 16 hours, the filtration loss reduction effect is good, indicating that the high-temperature resistant, salt-resistant, and hydrophobic polymers provided by this invention have good film-forming and sealing properties. In contrast, the monomer of Comparative Example 1 lacks fluorinated short-chain acrylates, and the filtration loss after aging is larger than that of Examples 1-4. Compared with Examples 1-4, Comparative Examples 2-4 have a poorer filtration loss reduction effect, but it is better than that of Comparative Example 1. This indicates that fluorine groups can form a hydrophobic and oleophobic layer on the surface of the mud cake, which is beneficial to reducing filtration loss.

[0100] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88… and 69-71 and 70-71, etc. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0101] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A high-temperature resistant, salt-resistant, cross-linked hydrophobic polymer, characterized in that, The polymer is obtained by copolymerization of raw materials containing 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomers, divinyl monomers and fluorinated short-chain acrylates; The mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomer, divinyl monomer, and fluorinated short-chain acrylate is 20:(5~8):(0.5~2):(3~5). The alkenyl polycyclic monomer is selected from any one of 1-vinyl-2-pyrrolidone, 5-vinyl-2-pyrrolidone, and 4-vinylpyridine. The method for preparing the polymer includes the following steps: (1) Prepare an aqueous solution containing 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomers, divinyl monomers, fluorinated short-chain acrylates and surfactants; (2) Adjust the pH of the aqueous solution, introduce nitrogen gas, and keep it warm; (3) Under nitrogen atmosphere protection, add initiator, stir, react, and obtain viscous glue solution; (4) The viscous liquid is dried, pulverized, and sieved to obtain the polymer. In step (3), the reaction temperature is 50~80℃.

2. The polymer according to claim 1, characterized in that, The divinyl monomers are selected from any one of divinylbenzene, 2,4-divinylpyridine, divinylbiphenyl, and divinyl sulfone; And / or, the fluorinated short-chain acrylate is selected from any one of trifluoroethyl methacrylate, hexafluorobutyl methacrylate, and dodecafluoroheptyl methacrylate; And / or, the number-average molecular weight of the polymer is 1.5 million to 2.2 million.

3. A method for preparing the polymer according to claim 1 or 2, characterized in that, Includes the following steps: (1) Prepare an aqueous solution containing 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomers, divinyl monomers, fluorinated short-chain acrylates and surfactants; (2) Adjust the pH of the aqueous solution, introduce nitrogen gas, and keep it warm; (3) Under nitrogen atmosphere protection, add initiator, stir, react, and obtain viscous glue solution; (4) The viscous liquid is dried, pulverized, and sieved to obtain the polymer. The mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomer, divinyl monomer, and fluorinated short-chain acrylate is 20:(5~8):(0.5~2):(3~5). The alkenyl polycyclic monomer is selected from any one of 1-vinyl-2-pyrrolidone, 5-vinyl-2-pyrrolidone, and 4-vinylpyridine. In step (3), the reaction temperature is 50~80℃.

4. The preparation method according to claim 3, characterized in that, In step (2), sodium hydroxide is used to adjust the pH of the solution to 7-10; And / or, in step (2), the temperature of the heat preservation is 10~30℃ and the time is 0.5~1h.

5. The preparation method according to claim 3, characterized in that, In step (3), the stirring speed is 600 r / min to 1200 r / min; And / or, in step (3), the reaction time is 3 to 8 hours.

6. The preparation method according to claim 3, characterized in that, In step (4), the viscous adhesive is dried at 100℃~105℃ until the moisture content is less than 10%; And / or, in step (4), the mesh size of the pulverized material is 200 mesh to 400 mesh.

7. The preparation method according to any one of claims 3 to 6, characterized in that, The surfactant is sodium dodecyl sulfate.

8. The preparation method according to any one of claims 3 to 6, characterized in that, The initiator is selected from one of azobisisobutyronitrile and azobisisoheptanenitrile.

9. The preparation method according to any one of claims 3 to 6, characterized in that, In the aqueous solution, the mass of water is 1.5 to 4 times the mass of the total monomers, which include 2-acrylamido-2-methylpropanesulfonic acid, alkenyl polycyclic monomers, divinyl monomers, and fluorinated short-chain acrylates.

10. The use of a polymer according to claim 1 or 2, or a polymer prepared by any one of claims 3 to 9, in a thickener for drilling fluids.

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