High-temperature-resistant and salt-resistant swellable particles and preparation method thereof

Abstract

The invention relates to the technical field of oilfield chemistry, in particular to high-temperature-resistant and salt-resistant swellable particles and a preparation method thereof, and the high-temperature-resistant and salt-resistant swellable particles comprise the following raw materials in parts by mass: 2000-2500 parts of a solvent, 350-450 parts of a first monomer, 180-250 parts of a second monomer, 50-80 parts of a third monomer, 50-80 parts of 2-acrylamide-2-methylpropanesulfonic acid, 120-180 parts of a suspension aid, 0.3-0.5 part of a cross-linking agent and 0.6-1.5 parts of an initiator. The high-temperature-resistant and salt-resistant volume expansion particle disclosed by the invention has relatively good temperature-resistant and salt-resistant plugging capability and shearing resistance.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemical technology, and in particular to a high-temperature and salt-resistant swellable particle and its preparation method. Background Technology

[0002] Swellable particles, as a functional material, have seen their development and application stem from in-depth exploration of the needs for fluid control and material plugging under complex geological conditions. The core characteristic of these materials lies in their physicochemical behavior of swelling upon contact with water and remaining stable in the presence of oil, giving them unique value in energy development, engineering construction, and environmental remediation. Their technological evolution can be traced back to the late 20th century, when traditional plugging materials gradually revealed limitations in high-temperature, high-pressure, heterogeneous strata, or high-permeability channels. For example, inorganic particles were prone to sedimentation, and chemical gels were greatly affected by the geological environment. This prompted researchers to shift towards developing intelligent materials with adaptive deformation capabilities.

[0003] The preparation process of bulk-swellable particles has undergone iterative upgrades from simple polymerization to refined control. Early products mostly used organic monomers and crosslinking agents to form a three-dimensional network structure through ground polymerization reaction, followed by granulation, drying, and pulverization to obtain particles with a specific particle size distribution. Although these materials have basic expansion properties, they have defects such as uneven particle size and insufficient mechanical strength. With the advancement of materials science, researchers have also focused on optimizing bulk-swellable particles. For example, patent number CN120424631A discloses "High temperature and salt resistance modified organic polymer bulk-swellable particles and their preparation method and application". It is prepared using reaction solvent, main monomer, salt-resistant monomer, temperature-resistant monomer, reinforcing monomer, crosslinking agent, initiator, stabilizer, and protective agent as main raw materials. These bulk-swellable particles have excellent salt and temperature resistance properties, simple preparation process, excellent performance, and are suitable for water control and shut-off in high-temperature and high-salt oil reservoirs.

[0004] However, the shear resistance of bulky particles is equally important, so there is an urgent need to develop a type of bulky particle that is resistant to high temperature and salt and has shear resistance. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature and salt-resistant bulk granule and its preparation method, so as to solve the problem that the current bulk granules have poor high-temperature and salt resistance but poor shear resistance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of this invention provides a high-temperature and salt-resistant swellable particle, comprising the following raw materials in parts by weight: 2000-2500 parts solvent, 350-450 parts first monomer, 180-250 parts second monomer, 50-80 parts third monomer, 50-80 parts 2-acrylamide-2-methylpropanesulfonic acid, 120-180 parts suspending agent, 0.3-0.5 parts crosslinking agent, and 0.6-1.5 parts initiator.

[0007] The present invention uses solvent, first monomer, second monomer, third monomer, 2-acrylamide-2-methylpropanesulfonic acid, suspending agent, crosslinking agent and initiator as main raw materials, wherein the first monomer is selected from acrylic acid, the second monomer is selected from acrylamide, and the third monomer is selected from a compound with a specific structure. The resulting bulk expanding agent has good salt resistance and high temperature resistance, and also has excellent shear resistance.

[0008] In some embodiments, the solvent is deionized water.

[0009] In some embodiments, the first monomer is acrylic acid.

[0010] In some embodiments, the second monomer is acrylamide.

[0011] In some embodiments, the structure of the third monomer is shown in Formula I. (I).

[0012] This application uses a third monomer with a specific structure to copolymerize with acrylic acid, acrylamide and 2-acrylamido-2-methylpropanesulfonic acid to prepare bulk-swellable particles, which can greatly improve the shear resistance of the bulk-swellable particles. The reason may be that in the compound shown in Formula I, the benzene ring has a planar rigid structure, which can increase the steric hindrance of the molecular chain when embedded in the polymer chain and restrict the free rotation of the chain segments. The five-membered ring structure of the pyrrole ring contains delocalized π electrons, which buffer stress through electron cloud deformation when subjected to shear. The two enhance the shear resistance through synergistic effect of different principles.

[0013] In some embodiments, the method for preparing the third monomer includes the following steps: (1) Under an inert protective atmosphere, methyl 4-amino-3-iodobenzoate and 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile were mixed and added to a mixture of degassed DMSO and deionized water. Then, diisopropylamine, dipotassium hydrogen phosphate and N-methylpyrrole were added. The mixture was stirred under blue LED irradiation at room temperature for 16-18 h. After the reaction, the mixture was extracted, the organic phases were combined, dried under reduced pressure, and subjected to column chromatography to obtain the compound shown in Formula II. (II); (2) Under an inert protective gas atmosphere, the compound represented by formula II in step (1) was mixed with tetrahydrofuran, and lithium hydroxide aqueous solution and methanol were added. The mixture was stirred at room temperature for 24-26 h to obtain the compound represented by formula III. (III); (3) Under an inert protective gas atmosphere, the compound shown in formula III in step (2) was mixed with pyridine and cooled to 0~5℃. Acryloyl chloride was added, and then the mixture was restored to room temperature and stirred for 16~18h. The mixture was dried under reduced pressure, extracted, and subjected to column chromatography to obtain the third monomer.

[0014] In some embodiments, in step (1), the molar ratio of methyl 4-amino-3-iodobenzoate and N-methylpyrrole is 1:(30~40).

[0015] Preferably, in step (1), the molar ratio of methyl 4-amino-3-iodobenzoate and N-methylpyrrole is 1:35.

[0016] In some embodiments, in step (1), the molar amount of 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile is 4-5 mol of methyl 4-amino-3-iodobenzoate.

[0017] Preferably, in step (1), the molar amount of 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile is 5 mol of methyl 4-amino-3-iodobenzoate.

[0018] In some embodiments, in step (1), the volume ratio of DMSO to deionized water is 1:(0.1~0.2).

[0019] Preferably, in step (1), the volume ratio of DMSO to deionized water is 1:0.1.

[0020] In some embodiments, in step (1), the molar ratio of methyl 4-amino-3-iodobenzoate, diisopropylamine and dipotassium hydrogen phosphate is 1:(2~2.5):(2~2.5).

[0021] Preferably, in step (1), the molar ratio of methyl 4-amino-3-iodobenzoate, diisopropylamine and dipotassium hydrogen phosphate is 1:2.3:2.3.

[0022] In some embodiments, in step (3), the molar ratio of the compound represented by Formula III to acryloyl chloride is 1:(1.2~1.5).

[0023] Preferably, in step (3), the molar ratio of the compound represented by Formula III to acryloyl chloride is 1:1.3.

[0024] In some embodiments, in step (3), the molar ratio of the compound represented by Formula III to pyridine is 1:(1.3~1.6).

[0025] Preferably, in step (3), the molar ratio of the compound represented by Formula III to pyridine is 1:1.4.

[0026] In some embodiments, the suspending agent is silica.

[0027] In some embodiments, the crosslinking agent is N,N-methylenebisacrylamide.

[0028] In some embodiments, the initiator is ammonium persulfate.

[0029] Another aspect of the present invention provides a method for preparing high-temperature and salt-resistant swellable particles, comprising the following steps: The first monomer, the second monomer, the third monomer, 2-acrylamide-2-methylpropanesulfonic acid and solvent are mixed and an inert protective gas is introduced. Then, a suspending agent, a crosslinking agent and an initiator are added. The mixture is allowed to stand and heated to 40~60℃ for 1~2 hours, then heated to 60~70℃ for 3~4 hours, and then heated to 70~80℃ for 9~10 hours to obtain a gel block. The gel block is crushed and dried to obtain high temperature and salt resistant granules.

[0030] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses solvent, first monomer, second monomer, third monomer, suspending agent, crosslinking agent and initiator as main raw materials, wherein the first monomer is selected from acrylic acid, the second monomer is selected from acrylamide, and the third monomer is selected from a compound with a specific structure. The prepared bulk expansion agent has good salt resistance and high temperature resistance, and also has excellent shear resistance.

[0031] (2) The application selects a third monomer with a specific structure to copolymerize with acrylic acid, acrylamide and 2-acrylamide-2-methylpropanesulfonic acid to prepare bulk-swellable particles, which can greatly improve the shear resistance of bulk-swellable particles. The reason may be that in the compound shown in Formula I, the benzene ring has a planar rigid structure, which can increase the spatial steric hindrance of the molecular chain when embedded in the polymer chain and restrict the free rotation of the chain segment. The five-membered ring structure of the pyrrole ring contains delocalized π electrons, which buffer stress through electron cloud deformation when subjected to shear. The two enhance the shear resistance through the synergistic effect of different principles. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0033] Unless otherwise specified, the post-processing operations described below, such as "degassing," "irradiation," "reduced pressure drying," "extraction," "combining organic phases," "column chromatography," "mixing," "stirring," "aging," and "standing," can be selected by those skilled in the art based on actual conditions, and are not further limited.

[0034] Preparation Example 1 The preparation method of the third monomer includes the following steps: (1) Under a N2 atmosphere, 0.1 mol of methyl 4-amino-3-iodobenzoate and 0.005 mol of 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile were mixed and added to a 300 mL mixture of degassed DMSO and deionized water (volume ratio 1:0.1). Then, 0.23 mol of diisopropylamine, 0.23 mol of dipotassium hydrogen phosphate and 3.5 mol of N-methylpyrrole were added. The mixture was stirred under 24 W blue LED irradiation at room temperature for 17 h. After the irradiation, the mixture was extracted, the organic phases were combined, dried under reduced pressure, and subjected to column chromatography (petroleum ether / ethyl acetate system) to obtain the compound shown in Formula II. (II); (2) Under a N2 atmosphere, 0.1 mol of the compound shown in formula II from step (1) was mixed with 200 ml of tetrahydrofuran, and 200 ml of 1N lithium hydroxide aqueous solution and 200 ml of methanol were added. The mixture was stirred at room temperature for 25 h to obtain the compound shown in formula III. (III); (3) Under a N2 atmosphere, 0.1 mol of the compound shown in formula III from step (2) was mixed with 0.14 mol of pyridine and cooled to 3°C. 0.13 mol of acryloyl chloride was added, and the mixture was then brought back to room temperature and stirred for 17 h. The mixture was dried under reduced pressure, extracted (dichloromethane / deionized water), and subjected to column chromatography (petroleum ether / dichloromethane system) to obtain the third monomer, the compound shown in formula I. (I).

[0035] Preparation Example 2 The preparation method of the third monomer includes the following steps: Under a nitrogen atmosphere, 0.1 mol of m-aminobenzoic acid and 0.14 mol of pyridine were mixed and cooled to 3 °C. 0.13 mol of acryloyl chloride was added, followed by stirring at room temperature for 17 h. The mixture was dried under reduced pressure, extracted (dichloromethane / deionized water), and subjected to column chromatography (petroleum ether / dichloromethane system) to obtain the third monomer, a compound as shown in Formula IV. (Ⅳ).

[0036] Preparation Example 3 The preparation method of the third monomer includes the following steps: Under a nitrogen atmosphere, 0.1 mol N-methylpyrrole and 0.01 mol Zn(OTf)₂·6H₂O were mixed and added to 300 mL of nitromethane. The mixture was cooled to 0 °C, and then 0.13 mol acryloyl chloride was added. The mixture was then heated to room temperature and stirred for 4 h. The mixture was then extracted (ethyl acetate / deionized water) and subjected to column chromatography (petroleum ether / ethyl acetate system) to give the third monomer, a compound as shown in Formula V. (V).

[0037] Example 1 A high-temperature and salt-resistant granular material comprises the following raw materials in parts by weight: 2300 parts deionized water, 400 parts acrylic acid, 200 parts acrylamide, 70 parts third monomer, 70 parts 2-acrylamido-2-methylpropanesulfonic acid, 150 parts silica, 0.4 parts N,N-methylenebisacrylamide, and 1 part ammonium persulfate.

[0038] The third monomer was prepared in Preparation Example 1.

[0039] The preparation method of the high-temperature and salt-resistant swellable particles in this embodiment includes the following steps: Acrylic acid, acrylamide, a third monomer, 2-acrylamido-2-methylpropanesulfonic acid, and deionized water were mixed and N2 was introduced. Then, silica, N,N-methylenebisacrylamide, and ammonium persulfate were added. The mixture was allowed to stand and heated to 50°C for 1.5 hours, then heated to 65°C for 3.5 hours, and then heated to 75°C for 9.5 hours to obtain a rubber block. The rubber block was crushed and dried to obtain high-temperature and salt-resistant granules.

[0040] Example 2 A high-temperature and salt-resistant granular material comprises the following raw materials in parts by weight: 2000 parts deionized water, 350 parts acrylic acid, 180 parts acrylamide, 50 parts third monomer, 50 parts 2-acrylamido-2-methylpropanesulfonic acid, 120 parts silica, 0.3 parts N,N-methylenebisacrylamide, and 0.6 parts ammonium persulfate.

[0041] The third monomer was prepared in Preparation Example 1.

[0042] The preparation method of the high-temperature and salt-resistant swellable particles in this embodiment includes the following steps: Acrylic acid, acrylamide, a third monomer, 2-acrylamido-2-methylpropanesulfonic acid and deionized water were mixed and N2 was introduced. Then, silica, N,N-methylenebisacrylamide and ammonium persulfate were added. The mixture was allowed to stand and heated to 40°C for 2 hours, then heated to 60°C for 4 hours, and then heated to 70°C for 10 hours to obtain a rubber block. The rubber block was crushed and dried to obtain high temperature and salt resistant granules.

[0043] Example 3 A high-temperature and salt-resistant granular material comprises the following raw materials in parts by weight: 2500 parts deionized water, 450 parts acrylic acid, 250 parts acrylamide, 80 parts third monomer, 80 parts 2-acrylamido-2-methylpropanesulfonic acid, 180 parts silica, 0.5 parts N,N-methylenebisacrylamide, and 1.5 parts ammonium persulfate.

[0044] The third monomer was prepared in Preparation Example 1.

[0045] The preparation method of the high-temperature and salt-resistant swellable particles in this embodiment includes the following steps: Acrylic acid, acrylamide, a third monomer, 2-acrylamido-2-methylpropanesulfonic acid and deionized water were mixed and N2 was introduced. Then, silica, N,N-methylenebisacrylamide and ammonium persulfate were added. The mixture was allowed to stand and heated to 60°C for 1 hour, then heated to 70°C for 3 hours, and then heated to 80°C for 9 hours to obtain a rubber block. The rubber block was crushed and dried to obtain high temperature and salt resistant granules.

[0046] Example 4 A high-temperature and salt-resistant swellable particle and its preparation method are described. The specific implementation method is the same as in Example 1, except that the third monomer is prepared by Example 2.

[0047] Example 5 A high-temperature and salt-resistant swellable particle and its preparation method are described. The specific implementation method is the same as in Example 1, except that the third monomer is prepared by Example 3.

[0048] Comparative Example 1 A high-temperature and salt-resistant swellable particle and its preparation method are described. The specific implementation method is the same as in Example 1, except that no third monomer is added.

[0049] Performance testing: (1) Blocking rate: The test was conducted in accordance with the method disclosed in Section 3.2.10, "Test of particle blocking performance," of the paper "Preparation and Research of Low-Cost Temperature- and Salt-Resistant Composite Bentonite Water-Ploughing Agent" published by Xinjiang University. (2) Compressive strength: The bulk-swelling particles were made into a gel with a water absorption ratio of 30 using deionized water. The gels were filtered out separately using a sample sieve, and the water at the bottom of the sieve was absorbed with filter paper. Equal amounts of the water-absorbing gel were weighed and placed into the sample cell of the compressor. The sample cell volume was 40 mm. 3 The plunger descends at a pressure rate of 50 mm / min, with a displacement of 2 / 3 of the sample cell. The formula for calculating the compressive strength is: P (MPa) = A (N) / S (mm). 2 ), where A is the force required when the gel begins to be extruded, and S is the area of ​​the gel subjected to the extrusion force when it is extruded, thus obtaining the compressive strength. The greater the compressive strength, the better the shear resistance. (3) Temperature resistance: The hydration temperature of the expanded granules during use was tested; The swollen particles of each embodiment and comparative example were tested according to the above method, and the results are shown in Table 1.

[0050] Table 1 Analysis of the data in Table 1 shows that the bulked particles prepared in Examples 1-3 have good shear resistance, sealing performance, and temperature resistance. In Example 4, the preparation method of the third monomer was changed, resulting in a decrease in the shear resistance and sealing performance of the bulked particles. In Example 5, the preparation method of the third monomer was changed, resulting in a decrease in the shear resistance, sealing performance, and temperature resistance of the bulked particles. In Comparative Example 1, the absence of the third monomer resulted in a decrease in the shear resistance and sealing performance of the bulked particles.

[0051] (4) Salt resistance test: Salt water with mineralization of 5000 mg / L, 10000 mg / L and 20000 mg / L was prepared as the solution water. The water absorption ratio of the swellable particles of Example 1 and Comparative Example 1 was tested by weight test method. The test data are shown in Table 2.

[0052] Table 2 According to the data in Table 2, the bulky particles prepared in Example 1 of this application have good salt resistance.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-temperature and salt-resistant swellable granule, characterized in that, It comprises the following raw materials in parts by weight: 2000-2500 parts solvent, 350-450 parts first monomer, 180-250 parts second monomer, 50-80 parts third monomer, 50-80 parts 2-acrylamide-2-methylpropanesulfonic acid, 120-180 parts suspending agent, 0.3-0.5 parts crosslinking agent and 0.6-1.5 parts initiator.

2. The high-temperature and salt-resistant swellable granules according to claim 1, characterized in that, The solvent is deionized water.

3. The high-temperature and salt-resistant swellable granules according to claim 1, characterized in that, The first monomer is acrylic acid.

4. The high-temperature and salt-resistant swellable granules according to claim 1, characterized in that, The second monomer is acrylamide.

5. The high-temperature and salt-resistant swellable granules according to claim 1, characterized in that, The structure of the third monomer is shown in Formula I. （Ⅰ）。 6. The high-temperature and salt-resistant swellable granules according to claim 5, characterized in that, The preparation method of the third monomer includes the following steps: (1) Under an inert protective atmosphere, methyl 4-amino-3-iodobenzoate and 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile were mixed and added to a mixture of degassed DMSO and deionized water. Then, diisopropylamine, dipotassium hydrogen phosphate and N-methylpyrrole were added. The mixture was stirred under blue LED irradiation at room temperature for 16-18 h. After the reaction, the mixture was extracted, the organic phases were combined, dried under reduced pressure, and subjected to column chromatography to obtain the compound shown in Formula II. （Ⅱ）； (2) Under an inert protective gas atmosphere, the compound represented by formula II in step (1) was mixed with tetrahydrofuran, and lithium hydroxide aqueous solution and methanol were added. The mixture was stirred at room temperature for 24-26 h to obtain the compound represented by formula III. （Ⅲ）； (3) Under an inert protective gas atmosphere, the compound shown in formula III in step (2) was mixed with pyridine and cooled to 0~5℃. Acryloyl chloride was added, and then the mixture was restored to room temperature and stirred for 16~18h. The mixture was dried under reduced pressure, extracted, and subjected to column chromatography to obtain the third monomer.

7. The high-temperature and salt-resistant swellable granules according to claim 6, characterized in that, In step (1), the molar ratio of methyl 4-amino-3-iodobenzoate, diisopropylamine and dipotassium hydrogen phosphate is 1:(2~2.5):(2~2.5).

8. The high-temperature and salt-resistant swellable granules according to claim 6, characterized in that, In step (3), the molar ratio of the compound represented by formula III to acryloyl chloride is 1:(1.2~1.5).

9. The high-temperature and salt-resistant swellable granules according to claim 1, characterized in that, The suspending agent is silica.

10. A method for preparing high-temperature and salt-resistant swellable granules according to any one of claims 1 to 9, characterized in that, Includes the following steps: The first monomer, the second monomer, the third monomer, 2-acrylamide-2-methylpropanesulfonic acid and solvent are mixed and an inert protective gas is introduced. Then, a suspending agent, a crosslinking agent and an initiator are added. The mixture is allowed to stand and heated to 40~60℃ for 1~2 hours, then heated to 60~70℃ for 3~4 hours, and then heated to 70~80℃ for 9~10 hours to obtain a gel block. The gel block is crushed and dried to obtain high temperature and salt resistant granules.

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