Graphene intercalation compound, preparation method and application thereof

Abstract

The application provides a graphene intercalation compound and a preparation method and application thereof. The graphene intercalation compound comprises graphene oxide and a polymer grafted on the graphene oxide, and the polymer comprises a structural unit derived from 2-acrylamide-2-methylpropane sulfonic acid and a structural unit derived from a second monomer, wherein the second monomer is selected from at least one of unsaturated acid and a salt thereof. By copolymerizing the graphene oxide with a large amount of oxygen-containing functional groups on the surface and a specific monomer, the polymer is grafted on the graphene sheet, a graphene intercalation compound with a specific structure is obtained, the purpose of improving the dispersion performance of the graphene material in the cement paste is achieved, and meanwhile, the intercalation compound can replace a traditional oil well cement dispersant and plays a role in improving the fluidity of the paste in the cement paste system.

Description

Technical Field

[0001] This invention relates to the field of additives for oil and gas cementing engineering, specifically to a graphene intercalation composite, its preparation method, and its application. Background Technology

[0002] The mud ring is a key factor in ensuring the annular seal within the wellbore. However, conventional cement stone is a brittle material, and cracks or micro-annular gaps easily appear in the cement ring during later production or operation stages of oil wells, leading to seal failure. To improve the strength and toughness of the cement ring, reinforcing and toughening materials are often added to the cement slurry system. Currently, commonly used strong and tough materials include inorganic nanoparticles, fibers, latex, rubber particles, and organic resins, among which inorganic nanoparticles have the best reinforcing effect and are the most widely used. However, inorganic nanoparticles are prone to agglomeration, and their poor dispersibility in cement slurry systems limits their further development. Graphene, as a two-dimensional nanomaterial, has a huge specific surface area, high surface energy, and large surface tension, which can improve and enhance the microstructure, mechanical properties, and durability of cement-based materials. However, due to its layered structure and high surface energy, graphene tends to agglomerate easily in cement slurry, resulting in uneven dispersion and slurry thickening.

[0003] CN 104140631 A discloses a graphene oxide / chitosan grafted dual-network hydrogel and its preparation method. The hydrogel has a dual-network structure, wherein the first network is a graphene oxide / chitosan grafted hydrogel, which is formed by grafting graphene oxide solution, chitosan solution, initiator, first monomer and crosslinking agent. The second network is interspersed inside the first network and is a hydrogel formed by polymerizing a second monomer, crosslinking agent and photoinitiator under ultraviolet light irradiation.

[0004] CN 113122076 A discloses a graphene oxide acrylic emulsion film, in which graphene oxide sheets are interwoven to form a three-dimensional network of graphene oxide sheets; the graphene oxide sheets are distributed throughout the entire film. The graphene oxide acrylic emulsion coating provided by this patent has a special structure, not only allowing the graphene oxide to be uniformly and orderly interwoven to form a three-dimensional network of interwoven graphene oxide sheets, but also enabling the graphene oxide sheets to be embedded in the polymer formed by the crosslinking of acrylic monomers and crosslinking monomers, thus ensuring uniform distribution throughout the film and solving the problem of graphene oxide agglomeration; moreover, the addition of these special crosslinking monomers improves the corrosion resistance and conductivity of the emulsion, with both complementing each other, laying a solid foundation for further improving the performance of water-based coatings.

[0005] The aforementioned patents all provide some degree of dispersibility for graphene oxide, but problems such as easy agglomeration, uneven dispersion, and slurry thickening may occur in cement slurry. Summary of the Invention

[0006] In view of the problems existing in the prior art, one of the objectives of the present invention is to provide a graphene intercalation composite. By copolymerizing graphene oxide with a large number of oxygen-containing functional groups on its surface with a specific monomer, a polymer is grafted onto the graphene sheets to obtain a graphene intercalation composite with a specific structure. This achieves the purpose of improving the dispersion performance of graphene materials in cement slurry. At the same time, the intercalation composite can replace the traditional oil well cement dispersant and play a role in improving the fluidity of the slurry in the cement slurry system.

[0007] The second objective of this invention is to provide a method for preparing a graphene intercalation composite corresponding to the first objective.

[0008] A third objective of this invention is to provide an application of a graphene intercalation composite corresponding to the above objectives.

[0009] To achieve one of the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A graphene intercalation composite comprising: graphene oxide and a polymer grafted onto the graphene oxide, the polymer comprising structural units derived from 2-acrylamide-2-methylpropanesulfonic acid and structural units derived from a second monomer, wherein the second monomer is selected from at least one of unsaturated acids and their salts.

[0011] In some preferred embodiments of the present invention, the second monomer is selected from at least one of acrylic acid, methacrylic acid, vinyl sulfonic acid, vinyl sulfonate, vinyl phosphoric acid, vinyl phosphate, maleic acid, maleic anhydride, itaconic acid, fumaric acid, styrene sulfonate, propylene sulfonate, and hydroxyethyl methacrylate.

[0012] In some preferred embodiments of the present invention, the second monomer is selected from at least one of acrylic acid and methacrylic acid.

[0013] In some preferred embodiments of the present invention, the polymer content is 80 wt% to 95 wt%, calculated based on the total mass of the graphene intercalation composite.

[0014] In some preferred embodiments of the present invention, the polymer content is 85 wt% to 95 wt%, calculated based on the total mass of the graphene intercalation composite.

[0015] In some preferred embodiments of the present invention, the content of graphene oxide is 5 wt% to 20 wt%, calculated based on the total mass of the graphene intercalation composite.

[0016] In some preferred embodiments of the present invention, the content of graphene oxide is 5 wt% to 15 wt%, calculated based on the total mass of the graphene intercalation composite.

[0017] In some preferred embodiments of the present invention, the polymer contains structural units derived from 2-acrylamide-2-methylpropanesulfonic acid and structural units derived from the second monomer in a mass ratio of (10-90):(90-10), preferably (20-80):(80-20), and more preferably (30-70):(70-30).

[0018] In some preferred embodiments of the present invention, the polymer contains structural units derived from 2-acrylamide-2-methylpropanesulfonic acid and structural units derived from the second monomer in a mass ratio of (1-9):1, preferably (1-7):1.

[0019] In some preferred embodiments of the present invention, the graphene oxide sheet size is 200-700 nm and the oxidation degree is 10%-50%.

[0020] To achieve the second objective mentioned above, the technical solution adopted by the present invention is as follows:

[0021] A method for preparing a graphene intercalation composite according to any one of the above embodiments, comprising:

[0022] S1. Provide a solution A containing the 2-acrylamide-2-methylpropanesulfonic acid and the second monomer, a solution B containing an initiator, a solution C containing a reducing agent, and a solution D containing the graphene oxide, respectively;

[0023] S2. Mix the solutions A, B, C, and D to obtain a reaction system;

[0024] S3. After allowing the reaction system to react for a period of time, terminate the reaction to obtain the graphene intercalation composite.

[0025] In some preferred embodiments of the present invention, in step S1, the initiator is ammonium persulfate.

[0026] In some preferred embodiments of the present invention, in step S1, the reducing agent is sodium bisulfite.

[0027] In some preferred embodiments of the present invention, in step S1, the mass percentage of 2-acrylamide-2-methylpropanesulfonic acid in solution A is 10wt% to 50wt%, preferably 15wt% to 40wt%.

[0028] In some preferred embodiments of the present invention, in step S1, the mass percentage of the second monomer in solution A is 5 wt% to 30 wt%, preferably 5 wt% to 20 wt%.

[0029] According to the present invention, in step S1, the mass ratio of 2-acrylamide-2-methylpropanesulfonic acid to the second monomer in solution A is (1-10):1. The inventors of this application have discovered that the higher the acrylic acid content, the better the fluidity of the cement slurry but the worse its strength. To balance the fluidity and strength of the cement slurry, the mass ratio of 2-acrylamide-2-methylpropanesulfonic acid to the second monomer is preferably (1-7):1.

[0030] In some preferred embodiments of the present invention, in step S1, the initiator in solution B has a mass percentage content of 2wt% to 6wt%.

[0031] In some preferred embodiments of the present invention, in step S1, the mass percentage of the reducing agent in solution C is 2wt% to 6wt%.

[0032] In some preferred embodiments of the present invention, in step S1, the mass percentage of graphene oxide in the solution D is 1 wt% to 10 wt%, preferably 2 wt% to 8 wt%.

[0033] According to the present invention, the amounts of solutions A, B, C and D are determined by the target product and the content of each component in the solution.

[0034] In some preferred embodiments of the present invention, in step S2, the mixing conditions include a mixing temperature of 30°C to 50°C.

[0035] According to the present invention, the order in which the solutions are added during the mixing process is not particularly restricted. Preferably, solutions A, B, and C are added to solution D simultaneously. The mixing can be carried out using a flow pump, which simultaneously pumps solutions A, B, and C into solution D. The pumping rate is determined by the volume of each solution, and preferably, the pumping is stopped simultaneously.

[0036] In some preferred embodiments of the present invention, in step S3, after the reaction system is kept at the mixing temperature for 1 h to 24 h, preferably 3 h to 12 h, the pH value of the reaction system is adjusted to neutral to terminate the reaction and obtain the graphene intercalation composite.

[0037] To achieve the third objective mentioned above, the technical solution adopted by the present invention is as follows:

[0038] Application of a graphene intercalation composite as described in any one of the above embodiments, or a graphene intercalation composite prepared according to any one of the above embodiments, in the field of oil and gas well cementing.

[0039] The application of a graphene intercalation composite as described in any one of the above embodiments, or a graphene intercalation composite prepared according to any one of the above embodiments, as a cement slurry additive.

[0040] In some preferred embodiments of the present invention, the graphene intercalation composite has a mass percentage of 1 wt% to 10 wt%, calculated based on the total mass of the cement slurry.

[0041] In some preferred embodiments of the present invention, the graphene intercalation composite has a mass percentage of 1 wt% to 5 wt%, calculated based on the total mass of the cement slurry.

[0042] In some preferred embodiments of the present invention, the graphene intercalation composite has a mass percentage of 1 wt% to 3 wt%, calculated based on the total mass of the cement slurry.

[0043] The beneficial effects of this invention are at least in the following aspects:

[0044] Firstly, the graphene intercalation composite provided by this invention has good hydrophilicity and is easy to prepare into a paste.

[0045] Secondly, the graphene intercalation composite provided by this invention has high temperature and salt resistance properties.

[0046] Thirdly, the graphene intercalation composite provided by this invention solves the problems of graphene material agglomeration, uneven dispersion, and slurry thickening in cement slurry, and can effectively improve the flow properties of cement slurry. The applicable temperature range is 25-150℃.

[0047] Fourth, the graphene intercalation composite provided by this invention is suitable for API oil well cement of all grades, and effectively improves the strength of cement stone while improving the fluidity of cement slurry. Detailed Implementation

[0048] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited to the following description.

[0049] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0050] In the following embodiments, unless otherwise specified, the graphene oxide used has a sheet size of 400 nm and an oxidation degree of 30%.

[0051] Example 1

[0052] Weigh 145g of 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 22g of acrylic acid (AA), and 256g of deionized water and add them to beaker A, mixing thoroughly. Weigh 3g of ammonium persulfate and 64g of deionized water and add them to beaker B, mixing thoroughly. Weigh 2g of sodium bisulfite and 26g of deionized water and add them to beaker C, mixing thoroughly. Weigh 450g of graphene oxide dispersion (5wt%) and add it to a four-necked flask equipped with a stirrer. Control the reaction system temperature at 40℃ and stir continuously. Simultaneously pump the mixture from beakers A, B, and C into the four-necked flask at a uniform rate using three flow pumps, controlling the pumping time to 1 hour. After pumping is completed, maintain the temperature and react for 5 hours. After the reaction is complete, adjust the pH of the system to neutral with sodium hydroxide, and dry in an oven to obtain a black powder, which is the graphene intercalation composite, i.e., sample 1.

[0053] Example 2

[0054] Weigh 10g of 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 4g of acrylic acid (AA), and 30g of deionized water and add them to beaker A, mixing thoroughly. Weigh 0.3g of ammonium persulfate and 6g of deionized water and add them to beaker B, mixing thoroughly. Weigh 0.2g of sodium bisulfite and 3g of deionized water and add them to beaker C, mixing thoroughly. Weigh 30g of graphene oxide dispersion (5wt%) and add it to a four-necked flask equipped with a stirrer. Control the reaction system temperature at 40℃ and stir continuously. Simultaneously pump the mixture from beakers A, B, and C into the four-necked flask at a uniform rate using three flow pumps, controlling the pumping time to 1 hour. After pumping is completed, maintain the temperature and react for 5 hours. After the reaction is complete, adjust the pH of the system to neutral with sodium hydroxide, and dry in an oven to obtain a black powder, which is the graphene intercalation composite, i.e., sample 2.

[0055] Example 3

[0056] Weigh 62g of 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 50g of acrylic acid (AA), and 240g of deionized water and add them to beaker A, mixing thoroughly. Weigh 3g of ammonium persulfate and 64g of deionized water and add them to beaker B, mixing thoroughly. Weigh 2g of sodium bisulfite and 26g of deionized water and add them to beaker C, mixing thoroughly. Weigh 150g of graphene oxide dispersion (5wt%) and add it to a four-necked flask equipped with a stirrer. Control the reaction system temperature at 40℃ and stir continuously. Simultaneously pump the mixture from beakers A, B, and C into the four-necked flask using three flow pumps at a uniform rate, controlling the pumping time to 1 hour. After pumping is completed, maintain the temperature and react for 5 hours. After the reaction is complete, adjust the pH of the system to neutral with sodium hydroxide, and dry in an oven to obtain a black powder, which is the graphene intercalation composite, i.e., sample 3.

[0057] Example 4

[0058] This embodiment is basically carried out in the same manner as Example 1, except that 39g of itaconic acid is used to replace 22g of acrylic acid (AA) in Example 1, resulting in Sample 4.

[0059] Example 5

[0060] This embodiment is basically carried out in the same manner as Example 1, except that 30g of sodium styrene sulfonate is used instead of 22g of acrylic acid (AA) in Example 1 to obtain Sample 5.

[0061] Test Example 1

[0062] Cement slurry was prepared according to GB / T 19139-2003 standard, and its rheological properties, stability, and compressive strength were evaluated.

[0063] Using 100 parts by weight of cement (Jiahua G grade), 2 parts by weight of water loss reducing agent (DZJ-Y), 0.8 parts by weight of dispersant (CPCE5), the graphene intercalation composite of this invention (the amounts are shown in Table 1), and 44 parts by weight of water, a solution with a density of 1.88 g / cm³ was prepared. 3 The cement slurry was cured at 50℃ for 72 hours, and the measurement results are shown in Table 1 below.

[0064] Table 1

[0065]

[0066] 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 graphene intercalation composite, comprising: Graphene oxide and a polymer grafted onto the graphene oxide, the polymer comprising structural units derived from 2-acrylamide-2-methylpropanesulfonic acid and structural units derived from a second monomer, wherein the second monomer is selected from at least one of acrylic acid, methacrylic acid, vinyl sulfonic acid, vinyl sulfonate, vinyl phosphoric acid, vinyl phosphate, maleic acid, maleic anhydride, itaconic acid, fumaric acid, styrene sulfonate, propylene sulfonate, and hydroxyethyl methacrylate. Based on the total mass of the graphene intercalation composite, the polymer content is 80wt%~95wt%; the graphene oxide content is 5wt%~20wt%; and In the polymer, the mass ratio of structural units derived from 2-acrylamide-2-methylpropanesulfonic acid to structural units derived from the second monomer is (1~9):

1. The preparation method of the graphene intercalation composite includes: S1. Provide a solution A containing the 2-acrylamide-2-methylpropanesulfonic acid and the second monomer, a solution B containing an initiator, a solution C containing a reducing agent, and a solution D containing the graphene oxide, respectively; S2. Mix the solutions A, B, C, and D to obtain a reaction system; S3. After allowing the reaction system to react for a period of time, terminate the reaction to obtain the graphene intercalation composite; In step S1, the reducing agent is sodium bisulfite; In step S2, the mixing conditions include: a mixing temperature of 30°C to 50°C; In step S3, the reaction system is kept at the mixing temperature for 1 h to 24 h, and the pH value of the reaction system is adjusted to neutral to terminate the reaction and obtain the graphene intercalation composite. The mixing is carried out by a flow pump, which simultaneously pumps solutions A, B, and C into solution D. The pumping rate is determined by the volume of each solution, so that the pumping of solutions A, B, and C ends simultaneously.

2. The graphene intercalation composite according to claim 1, characterized in that, The second monomer is selected from at least one of acrylic acid and methacrylic acid.

3. The graphene intercalation composite according to claim 1 or 2, characterized in that, Based on the total mass of the graphene intercalation composite, the content of the polymer is 85wt%~95wt%; and the content of the graphene oxide is 5wt%~15wt%.

4. The graphene intercalation composite according to claim 1 or 2, characterized in that, In the polymer, the mass ratio of structural units derived from 2-acrylamide-2-methylpropanesulfonic acid to structural units derived from the second monomer is (1~7):

1.

5. The graphene intercalation composite according to claim 1 or 2, characterized in that, The graphene oxide sheets have a size of 200-700 nm and an oxidation degree of 10%-50%.

6. A method for preparing a graphene intercalation composite according to any one of claims 1-5, comprising: S1. Provide a solution A containing the 2-acrylamide-2-methylpropanesulfonic acid and the second monomer, a solution B containing an initiator, a solution C containing a reducing agent, and a solution D containing the graphene oxide, respectively; S2. Mix the solutions A, B, C, and D to obtain a reaction system; S3. After allowing the reaction system to react for a period of time, terminate the reaction to obtain the graphene intercalation composite; In step S1, the reducing agent is sodium bisulfite; In step S2, the mixing conditions include: a mixing temperature of 30°C to 50°C; In step S3, the reaction system is kept at the mixing temperature for 1 h to 24 h, and the pH value of the reaction system is adjusted to neutral to terminate the reaction and obtain the graphene intercalation composite. The mixing is carried out by a flow pump, which simultaneously pumps solutions A, B, and C into solution D. The pumping rate is determined by the volume of each solution, so that the pumping of solutions A, B, and C ends simultaneously.

7. The preparation method according to claim 6, characterized in that, In step S1, the initiator is ammonium persulfate.

8. The preparation method according to claim 6 or 7, characterized in that, In step S1, the 2-acrylamide-2-methylpropanesulfonic acid in solution A has a mass percentage content of 10wt%~50wt%; the second monomer has a mass percentage content of 5wt%~20wt%; and / or In solution B, the initiator has a mass percentage content of 2wt%~6wt%; and / or In solution C, the reducing agent has a mass percentage content of 2wt%~6wt%; and / or In the solution D, the mass percentage of graphene oxide is 1wt% to 10wt%.

9. The preparation method according to claim 8, characterized in that, In step S1, the mass percentage of 2-acrylamide-2-methylpropanesulfonic acid in solution A is 15wt%~40wt%; the mass percentage of the second monomer is 5wt%~20wt%; and / or In the solution D, the mass percentage of graphene oxide is 2wt%~8wt%.

10. In the preparation method according to claim 6 or 7, in step S3, the reaction system is maintained at the temperature at which it is mixed for 3 h to 12 h.

11. The application of a graphene intercalation composite according to any one of claims 1-5 or a graphene intercalation composite prepared by any one of claims 6-10 in the field of oil and gas well cementing.

12. The application according to claim 11, characterized in that, The application is as an additive for cement slurry.

13. The application according to claim 12, characterized in that, Based on the total mass of the cement slurry, the mass percentage of the graphene intercalation composite is 1 wt% to 10 wt%.

14. The application according to claim 13, characterized in that, Based on the total mass of the cement slurry, the mass percentage of the graphene intercalation composite is 1 wt% to 5 wt%.

15. The application according to claim 14, characterized in that, Based on the total mass of the cement slurry, the mass percentage of the graphene intercalation composite is 1 wt% to 3 wt%.

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