A Displacement Agent Based on Flaky Granular Materials, Its Preparation Method and Application

Abstract

The present invention discloses an oil displacement agent based on sheet-like particulate materials, its preparation method and application. The oil displacement agent includes amphiphilic graphene-like nanosheets and an amphiphilic graphene-like nanosheet dispersion system. The amphiphilic graphene-like nanosheets include graphene-like nanosheet synthesis raw materials and alkylamine monomers. The amphiphilic graphene-like nanosheet dispersion system includes surfactants. The oil displacement agent of the present invention has the characteristics of small size, large specific surface area, and interfacial activity, has good dispersion performance in water, and can be used as a solid particulate surfactant. The method is simple and easy to implement, can achieve mass production, and can regulate its amphiphilicity by adjusting the types of modified reactants or the ratio of the two reactants. The oil displacement agent of the present invention can produce a synergistic effect alone or in combination with traditional surfactants, and has good properties of stripping and emulsifying oil droplets and an oil displacement effect.

Description

Technical Field

[0001] The present invention relates to the technical field of oil displacement, and particularly relates to an oil displacement agent based on sheet-like particulate materials, a preparation method thereof, and an application thereof. Background Art

[0002] Chemical flooding is one of the methods for improving oil recovery in oilfields. Among them, surfactants are commonly used chemical agents in binary and ternary composite flooding technologies. Adding an appropriate amount of surfactant to the injected water can significantly reduce the interfacial tension between the injected water and the residual oil in the formation, displace the residual oil, and thus improve the oil recovery. Surfactants are usually molecular surfactants, but solid particles can also be used as surface active substances to form Pickering emulsions. Compared with the emulsions formed by traditional surfactants, the required concentration of solid particles is much lower than that of traditional surfactants, which is beneficial to cost savings. At the same time, it is not easily affected by external conditions and has stronger stability.

[0003] Graphene nanosheets have characteristics such as a large specific surface area and small size, making them highly valuable in fields such as surfactants and environmental monitoring. Surfactants usually contain hydrophilic groups and hydrophobic groups. By modifying graphene nanosheets with hydrophobic groups, the amphiphilicity of graphene nanosheets can be effectively improved to enhance the interaction between the nanosheets and oil and water.

[0004] There are many modification methods for graphene nanosheets. Especially the graphene nanosheets prepared by the bottom-up method have attracted attention due to their many surface active centers, controllable size, and wide range of raw materials. Commonly, the reaction of graphene nanosheet raw materials with modifiers in solution, and the reaction of the two in an autoclave under hydrothermal conditions. These methods can effectively modify graphene nanosheets and are widely used in various experiments. However, these methods require the treatment of a large amount of reaction solvents and relatively high reaction conditions.

[0005] According to previous reports, the modified graphene nanosheets have high dispersibility, high catalytic activity, and high interfacial activity. The literature reports that due to the excellent amphiphilicity of graphene nanosheets and a large number of active sites, the modified amphiphilic graphene nanosheets have self-assembly performance, high surface catalytic performance, and improved interfacial polymerization stability. Summary of the Invention

[0006] In the present invention, alkylamine and graphene-like nanoplate synthesis raw materials are directly used for reaction, and no solvent is used during the reaction process. Graphene-like nanoplate with adjustable amphiphilicity can be prepared, which has good interfacial activity and can effectively improve the oil displacement efficiency. The present invention aims to overcome the problems existing in the background technology and provides a preparation method of amphiphilic graphene nanoplate modified with hydrophobic groups for oil displacement. The prepared amphiphilic graphene nanoplate has good interfacial properties, emulsifying properties and oil displacement effect as a surfactant under neutral conditions. To achieve the above object, the present invention provides the following technical solutions:

[0007] An oil displacement agent based on sheet-like particulate materials, the oil displacement agent comprising amphiphilic graphene-like nanoplate, and the amphiphilic graphene-like nanoplate comprising: graphene-like nanoplate synthesis raw materials and alkylamine monomers, wherein the mass ratio of the graphene-like nanoplate synthesis raw materials to the alkylamine monomers is 1:1 to 100:1.

[0008] Preferably, the oil displacement agent further comprises an amphiphilic graphene-like nanoplate dispersion system;

[0009] The amphiphilic graphene-like nanoplate dispersion system comprises a surfactant, wherein the amphiphilic graphene-like nanoplate is 0.05 to 1.0 wt%, and the surfactant concentration is 0.0 to 3.0 wt%.

[0010] Preferably, the graphene-like nanoplate raw materials include but are not limited to any one of glucose, mannose, glutamic acid, citric acid, lignin and ethylenediamine.

[0011] Preferably, the alkylamine monomers include but are not limited to any one of heptylamine, dodecylamine, hexadecylamine and octadecylamine.

[0012] Preferably, the amphiphilic graphene-like nanoplate is in a sheet-like structure and comprises lipophilic groups and hydrophilic groups;

[0013] The size of the amphiphilic graphene-like nanoplate is 30 nm to 10 μm.

[0014] Preferably, the amphiphilic graphene-like nanoplate can be orderly arranged at the water / oil interface to form a Pickering emulsion.

[0015] Preferably, the surfactant includes but is not limited to any one of petroleum sulfonate, heavy alkylbenzene sulfonate and betaine.

[0016] A preparation method of an oil displacement agent based on sheet-like particulate materials, the method comprising the following steps:

[0017] Mix and stir the graphene-like nanoplate synthesis raw materials and the alkylamine monomers to obtain a mixture;

[0018] React the mixture in an air environment to obtain a product;

[0019] Dissolve, wash, and dry the product to obtain amphiphilic graphene-like nanosheets modified with hydrophobic groups.

[0020] Preferably, the method further includes the following steps:

[0021] Stir the amphiphilic graphene-like nanosheets, surfactant solution, and water uniformly, adjust the pH to 7 - 9, and obtain an amphiphilic graphene-like nanosheet dispersion system through hydrogen bonding.

[0022] Preferably, the mixing and stirring rate of the graphene-like nanosheet synthesis raw materials and the alkylamine monomer is 500 - 1500 rpm, and the stirring time is 60 - 150 seconds.

[0023] Preferably, the conditions for reacting the mixture in an air environment are 150 - 250 °C for 0.5 - 3 h.

[0024] Preferably, the solvent for dissolving the product includes but is not limited to any one of dichloromethane, diethyl ether, or toluene.

[0025] Preferably, the washing includes washing successively with hydrochloric acid solution, sodium bicarbonate solution, and deionized water.

[0026] Preferably, the drying conditions are 25 - 70 °C for 8 - 24 h.

[0027] An application of an oil displacement agent based on sheet-like particulate materials, the application of the oil displacement agent in enhancing oil recovery by chemical flooding.

[0028] Preferably, the oil displacement agent is applied to the fields of Pickering emulsion, interfacial polymerization, interfacial catalysis, and enhanced oil recovery. Technical effects and advantages of the present invention:

[0029] 1. The present invention provides an oil displacement agent based on sheet-like particulate materials, its preparation method and application. The oil displacement agent is an amphiphilic graphene-like nanosheet and an amphiphilic graphene-like nanosheet dispersion system. The amphiphilic graphene-like nanosheets are directly obtained by reacting an alkylamine and graphene-like nanosheet synthesis raw materials, and no solvent is used during the reaction process. The amphiphilic graphene-like nanosheets, surfactant solution, and water are stirred uniformly, the pH is adjusted to 7 - 9, and an amphiphilic graphene-like nanosheet dispersion system is obtained through hydrogen bonding.

[0030] 2. The amphiphilic graphene-like nanosheets in the present invention have both hydrophilic and lipophilic groups, can be orderly arranged at the water / oil interface to form a Pickering emulsion, exhibit excellent interfacial tension reduction performance, and can greatly improve the oil recovery rate. They have good interfacial performance, emulsification performance, and oil displacement effect under neutral conditions.

[0031] Other features and advantages of the present invention will be described in the subsequent specification, and, in part, will be apparent from the specification or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained by the structures pointed out in the specification, the claims and the drawings. Description of the Drawings

[0032] Figure 1 Transmission electron microscope image of amphiphilic graphene-like nanosheets;

[0033] Figure 2 Atomic force microscope image of amphiphilic graphene-like nanosheets;

[0034] Figure 3 XPS elemental analysis image of amphiphilic graphene-like nanosheets;

[0035] Figure 4a Photograph of the Pickering emulsion formed by amphiphilic graphene-like nanosheets and the oil phase dodecane in the examples;

[0036] Figure 4b Microscopic morphology image of the Pickering emulsion formed by amphiphilic graphene-like nanosheets and the oil phase dodecane in the examples;

[0037] Figure 4c Morphology image of the Pickering emulsion formed by amphiphilic graphene-like nanosheets and the oil phase dodecane in the dynamic microfluidic chip in the examples;

[0038] Figure 4d Photograph of the Pickering emulsion formed by amphiphilic graphene-like nanosheets and crude oil in the examples;

[0039] Figure 5 Surface tension performance image of the water-oil system of amphiphilic graphene-like nanosheets in the examples. Detailed Description of the Invention

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0041] To address the deficiencies of the existing technology, the present invention discloses a displacing agent based on a flaky particle structure, its preparation method and application. A displacing agent based on flaky particle materials includes amphiphilic graphene-like nanosheets and an amphiphilic graphene-like nanosheet dispersion system. The amphiphilic graphene-like nanosheets include graphene-like nanosheet synthesis raw materials and alkylamine monomers, where the mass ratio of the graphene-like nanosheet synthesis raw materials to the alkylamine monomers is 1:1 to 100:1. The amphiphilic graphene-like nanosheet dispersion system includes hydrophilic graphene-like nanosheets and surfactants, which is a mixture with the chemical structure characteristics of the material itself unchanged. Among them, the amphiphilic graphene-like nanosheets are 0.05 to 0.5 wt%, and the surfactant concentration is 0.0 to 3.0 wt%.

[0042] Different from traditional graphene flaky materials, in the work of the present invention, a method of synthesizing with small molecule carbon source compounds is adopted, and the obtained product is highly similar to traditional graphene sheets in chemical structure, composition and performance, and has a lower cost, so it is called graphene-like nanosheets.

[0043] As Figures 1-3 shown, Figure 1 Figure (a) is the transmission electron microscope image of amphiphilic graphene-like nanosheets, Figure 2 Figure (b) is the atomic force microscope image of amphiphilic graphene-like nanosheets, Figure 3 Figure (c) is the XPS elemental analysis diagram of amphiphilic graphene-like nanosheets. Combining Figures 1-2 it can be seen that the size of the graphene-like nanosheets is at the nanometer level and the distribution is uniform. Combining Figure 3 it can be seen that for the high-resolution C 1s , O 1s and N 1s XPS spectra, the characteristic peaks at binding energies of 284.7, 398.8 and 531.3 eV, C 1s can correspond to C-C bonds, N 1s corresponds to N-C bonds and O 1s corresponds to C-O bonds (carbonyl oxygen and hydroxyl oxygen).

[0044] Furthermore, the amphiphilic graphene-like nanosheets are in a flaky structure, including hydrophobic groups and hydrophilic-lipophilic groups. The size of the amphiphilic graphene-like nanosheets is 30 nm to 10 μm, and the amphiphilic graphene-like nanosheets can be arranged orderly at the water / oil interface to form a Pickering emulsion.

[0045] Furthermore, the surfactant can be an anionic surfactant, an anionic-nonionic surfactant and an amphoteric surfactant, including but not limited to one of petroleum sulfonate, heavy alkylbenzene sulfonate and betaine.

[0046] A preparation method of amphiphilic graphene-like nanosheets. First, the raw materials for synthesizing graphene-like nanosheets and alkylamine monomers are mixed at a mass ratio of 1:1 to 100:1 to obtain a mixture; the mixture is mixed for 60 to 150 seconds under the condition that the stirring rate is 500 to 1500 rpm; the mixture is reacted in an air environment at 150 - 250 °C for 0.5 to 3 h to obtain a product, and the size of the product increases continuously with the increase of the reaction time; after the product is dissolved, it is washed and dried to obtain amphiphilic graphene-like nanosheets modified with hydrophobic groups. The size of the amphiphilic graphene-like nanosheets is closely related to the reaction time. Within a certain range, the size increases with the increase of time, and the size includes 30 nm to 10 μm.

[0047] The amphiphilic graphene-like nanosheets, surfactant solution and water are stirred evenly, and the pH is adjusted to 7 - 9 to form an amphiphilic graphene-like nanosheet dispersion system through hydrogen bonding and other interactions.

[0048] Furthermore, the raw materials for synthesizing graphene-like nanosheets can be any one of glucose, mannose, glutamic acid, citric acid, lignin, and ethylenediamine.

[0049] Furthermore, the alkylamine monomer is any one of heptylamine, dodecylamine, hexadecylamine, and octadecylamine.

[0050] Furthermore, the solvent for dissolving the product is any one of dichloromethane, diethyl ether, and toluene.

[0051] Furthermore, the washing is carried out successively with hydrochloric acid solution, sodium bicarbonate solution and deionized water.

[0052] The oil displacement agent of the present invention includes amphiphilic graphene-like nanosheets and an amphiphilic graphene-like nanosheet dispersion system. Both the amphiphilic graphene-like nanosheets and the amphiphilic graphene-like nanosheet dispersion system are modified with hydrophobic groups and can be used in the fields of Pickering emulsion, interfacial polymerization, interfacial catalysis and enhanced oil recovery.

[0053] When the amphiphilic graphene-like nanosheets of the oil displacement agent of the present invention are dispersed in water, the mass fraction of the amphiphilic graphene-like nanosheets in the aqueous solution is 0.05 - 0.5 wt%, and at room temperature, the interfacial tension value between dodecane / water can be decreased from 50 mN / m to 20 mN / m.

[0054] The oil displacement agent of the present invention is dispersed in water to obtain an oil displacement aqueous solution. The mass fraction of the oil displacement agent in the aqueous solution is 0.05 - 1.0 wt%, and the enhanced oil recovery rate measured at room temperature is greater than 50%.

[0055] The oil displacement agent of the present invention uses small molecule carbon source as raw material and mixes it with modified reactants, and directly carries out high-temperature carbonization reaction in air environment. This method is simple and easy to operate, can realize mass production, and can regulate its amphiphilicity by adjusting the type of modified reactants or the ratio of the two reactants. The obtained sheet-like graphene-based particle oil displacement material has the characteristics of small size, large specific surface area, and interfacial activity, has good dispersion performance in water, and can be used as a solid particle surfactant. This sheet-like graphene-based particle material can produce synergistic effects alone or in combination with traditional surfactants, has good performance in stripping and emulsifying oil droplets and oil displacement effect. Using a microfluidic chip model to simulate the displacement process, it is confirmed that it can effectively improve the oil recovery rate.

[0056] The technical solution of the present invention will be further described according to specific embodiments.

[0057] Example 1

[0058] This example provides a preparation method of amphiphilic graphene-like nanosheets, including the following steps:

[0059] Weigh 2g of citric acid and 1g of dodecylamine and place them in a beaker. After mixing evenly by mechanical stirring at room temperature for 90 seconds, place the beaker in an oven, raise the temperature to 200°C, and react for 2h under open aerobic conditions; after the reaction product is allowed to stand and cool to room temperature, dissolve the product in dichloromethane, wash it once with 0.01M hydrochloric acid solution, wash it twice with 5wt% sodium bicarbonate solution, and finally wash it with deionized water until neutral. Dry the treated dichloromethane solution at 25°C for 12h to obtain a solid of amphiphilic graphene-like nanosheets.

[0060] The transmission electron microscope image of the amphiphilic graphene-like nanosheets in this example is as Figure 1 shown. It can be seen from Figure 1 that there is an obvious sheet structure, and the particle size of the finally obtained amphiphilic graphene-like nanosheet material is about 20nm.

[0061] The atomic force microscope image is as Figure 2 shown. It can be seen from Figure 2 that the thickness of the graphene-like nanosheets is 2 - 6nm, which indicates that the obtained graphene-like nanosheets are in a sheet layer structure.

[0062] The XPS image of the graphene-like nanosheets is as Figure 3 shown. It can be seen from Figure 3 that the carboxyl group reacts with the amine group, introducing hydrophobic groups. From the figure, the proportion range of the hydrophobic groups modifying the carboxyl group is 50% - 70%.

[0063] The amphiphilic graphene oxide nanosheets modified with hydrophobic groups prepared by the present invention have good emulsifying properties.

[0064] The amphiphilic graphene oxide nanosheets were formulated into an aqueous solution with a mass fraction of 0.1%. Add two phases of dodecane and deionized water into a plastic tube, and the volume fraction of dodecane is 7%. Add the prepared graphene oxide nanosheet aqueous solution into the plastic tube, and after mixing for 30 s under the condition of 1500 rpm, the obtained Pickering emulsion is shown in Figure 4. Using dodecane and real crude oil as the oil phase in the oil-water emulsion respectively, and amphiphilic graphene oxide nanosheets as the emulsifier, Pickering emulsions were prepared. Among them, Figure 4a is the Pickering emulsion formed by amphiphilic graphene oxide nanosheets and the oil phase dodecane, Figure 4b is the microscopic morphology diagram of the formed Pickering emulsion, Figure 4c is the morphology diagram of the formed Pickering emulsion in the dynamic microfluidic chip, Figure 4d is the Pickering emulsion formed by amphiphilic graphene oxide nanosheets and crude oil. The formation of the emulsion can improve the fluidity of crude oil to a certain extent, reduce the viscosity of crude oil, and improve the oil displacement efficiency.

[0065] The amphiphilic graphene oxide nanosheets modified with hydrophobic groups prepared by the present invention can reduce the interfacial tension between dodecane / water as a surfactant.

[0066] The interfacial tension was measured by the pendant drop method. The experimental oil phase was dodecane and the experimental water phase was deionized water. The amphiphilic graphene oxide nanosheets were formulated into an aqueous solution with deionized water as a surfactant. For example, the concentration of the surfactant was 0.05 - 0.5%. At room temperature, the interfacial tension between dodecane / water was measured to decrease from 53 mN / m to 21 mN / m, as Figure 5 shown.

[0067] The amphiphilic graphene oxide nanosheets modified with hydrophobic groups prepared by the present invention can improve the oil displacement efficiency as a surfactant. The test method is as follows:

[0068] At room temperature, dodecane (which can be stained with Sudan red) was injected as the oil phase to fill the entire microfluidic chip. Subsequently, the chip was left standing with the oil phase for a period of time, and deionized water was injected into the chip with a syringe pump to simulate the water flooding process. When the oil production rate could no longer be changed by water flooding and reached a stable state, the oil production rate was calculated to be 31% using image processing software. After water flooding, the displacement was carried out again with a suspension of flaky particles. The test found that the oil production rate reached 52%. The experimental results show that the flaky graphene oxide particle material of the present invention further increases the recovery rate by 21 percentage points on the basis of water flooding.

[0069] Example 2

[0070] This embodiment provides a method for preparing amphiphilic graphene-like nanosheets, which specifically includes the following steps:

[0071] Weigh 2 g of citric acid and 1 g of octylamine and place them in a beaker. After mechanically stirring for 90 seconds at room temperature to mix evenly, place the beaker in an oven. Raise the temperature to 200 °C and react for 2.5 h under open and aerobic conditions. After the reaction, let the product stand and cool down to room temperature. Then dissolve the product in dichloromethane, wash it once with 0.01 M hydrochloric acid solution, wash it twice with 5 wt% sodium bicarbonate solution, and finally wash it with deionized water until neutral. Dry the treated dichloromethane solution at 25 °C for 12 h to obtain a solid of amphiphilic graphene-like nanosheets. The amphiphilic graphene-like nanosheets in this embodiment have surfactant properties and can form a stable emulsion.

[0072] Dissolve the amphiphilic graphene-like nanosheets in water, mix them with an aqueous solution of petroleum sulfonate surfactant, and adjust the pH to 7 - 9 to obtain a dispersion system of amphiphilic graphene-like nanosheets with a mass fraction of 0.1%. Use this system to carry out an oil displacement experiment. The oil displacement test method is the same as that in Example 1, and the measured oil recovery rate increases by 25 percentage points.

[0073] Example 3

[0074] This embodiment provides a method for preparing amphiphilic graphene-like nanosheets, which specifically includes the following steps:

[0075] Weigh 2 g of glutamic acid and 1.2 g of octylamine and place them in a beaker. After mechanically stirring for 90 seconds at room temperature to mix evenly, place the beaker in an oven. Raise the temperature to 190 °C and react for 2.5 h under open and aerobic conditions. After the reaction, let the product stand and cool down to room temperature. Then dissolve the product in dichloromethane, wash it once with 0.01 M hydrochloric acid solution, wash it twice with 3 wt% sodium bicarbonate solution, and finally wash it with deionized water until neutral. Dry the treated dichloromethane solution at 25 °C for 15 h to obtain a solid of amphiphilic graphene-like nanosheets.

[0076] The amphiphilic graphene-like nanosheets in this embodiment have surfactant properties and can form a stable emulsion. Dissolve the amphiphilic graphene nanosheets in water to obtain an aqueous solution with a mass fraction of 0.1%. The oil displacement test method is the same as that in Example 1, and the measured oil recovery rate increases by 13 percentage points.

[0077] Example 4

[0078] This embodiment provides a method for preparing amphiphilic graphene-like nanosheets, which specifically includes the following steps:

[0079] Weigh 2 g of glucose and 0.5 g of octadecylamine and place them in a beaker. Stir mechanically at room temperature for 90 seconds to mix evenly. Then, place the beaker in an oven, raise the temperature to 190 °C, and react for 2 h under open-air aerobic conditions. After the reaction, let the product stand and cool down to room temperature. Then, dissolve the product in dichloromethane, wash it once with 0.01 M hydrochloric acid solution, twice with 3 wt% sodium bicarbonate solution, and finally wash it with deionized water until neutral. Dry the treated dichloromethane solution at 25 °C for 15 h to obtain a solid of amphiphilic graphene-like nanosheets.

[0080] The amphiphilic graphene-like nanosheets in this example have surfactant properties and can form stable emulsions. Dissolve the amphiphilic graphene-like nanosheets in water to obtain an aqueous solution with a mass fraction of 0.1%. The oil displacement test method is the same as that in Example 1, and the measured oil recovery rate increases by 18 percentage points.

[0081] Example 5

[0082] This example provides a preparation method for amphiphilic graphene-like nanosheets, which specifically includes the following steps:

[0083] Weigh 2 g of lignin and 1.2 g of dodecylamine and place them in a beaker. Stir mechanically at room temperature for 90 seconds to mix evenly. Then, place the beaker in an oven, raise the temperature to 220 °C, and react for 2 h under open-air aerobic conditions. After the reaction, let the product stand and cool down to room temperature. Then, dissolve the product in dichloromethane, wash it once with 0.01 M hydrochloric acid solution, twice with 3 wt% sodium bicarbonate solution, and finally wash it with deionized water until neutral. Dry the treated dichloromethane solution at 25 °C for 12 h to obtain a solid of amphiphilic graphene-like nanosheets.

[0084] The amphiphilic graphene-like nanosheets in this example have surfactant properties and can form stable emulsions. Dissolve the amphiphilic graphene-like nanosheets in water to obtain an aqueous solution with a mass fraction of 0.1%. The oil displacement test method is the same as that in Example 1, and the measured oil recovery rate increases by 14 percentage points.

[0085] Based on the above examples and experimental evaluation results, it shows that the present invention provides a preparation method for amphiphilic graphene-like nanosheets modified with hydrophobic groups, which can prepare a large amount of small-sized graphene nanosheets. The hydrophilic-lipophilic degree of the amphiphilic graphene-like nanosheets can be regulated by changing the types of graphene-like nanosheet raw materials and alkylamines, as well as the ratio of the two reactants. The amphiphilic graphene-like nanosheets prepared by this method maintain the properties of the graphene nanosheets themselves. At the same time, due to the effective improvement of amphiphilicity after the modification of the graphene nanosheets with alkyl chains, they can be used as surfactants to significantly reduce the oil / water interfacial tension. At the same time, in the simulated oil displacement experiment, they have a high oil displacement efficiency.

[0086] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of an oil displacement agent based on sheet-like particulate materials, characterized in that, the method comprises the following steps: Mix and stir the graphene-like nanosheet synthesis raw materials and alkylamine monomers to obtain a mixture; the graphene-like nanosheet raw materials include but are not limited to any one of glucose, mannose, glutamic acid, citric acid, lignin, and ethylenediamine; The alkylamine monomers include but are not limited to any one of heptylamine, dodecylamine, hexadecylamine, and octadecylamine; The mass ratio of the graphene-like nanosheet synthesis raw materials to the alkylamine monomers is 1:1 - 100:1; React the mixture in an air environment to obtain a product; the reaction conditions of the mixture in an air environment are 150 - 250 °C and 0.5 - 3 h; Dissolve, wash, and dry the product to obtain amphiphilic graphene-like nanosheets modified with hydrophobic groups.

2. The preparation method of an oil displacement agent based on sheet-like particulate materials according to claim 1, characterized in that, the method further comprises the following steps: Stir the amphiphilic graphene-like nanosheets, surfactant solution, and water uniformly, adjust the pH to 7 - 9, and obtain an amphiphilic graphene-like nanosheet dispersion system through hydrogen bonding.

3. The preparation method of an oil displacement agent based on sheet-like particulate materials according to claim 1, characterized in that, The mixing and stirring rate of the graphene-like nanosheet synthesis raw materials and the alkylamine monomers is 500 - 1500 rpm, and the stirring time is 60 - 150 seconds.

4. The preparation method of an oil displacement agent based on sheet-like particulate materials according to claim 1, characterized in that, The solvents for dissolving the product include but are not limited to any one of dichloromethane, ether, or toluene.

5. The preparation method of an oil displacement agent based on sheet-like particulate materials according to claim 1, characterized in that, The washing includes washing successively with hydrochloric acid solution, sodium bicarbonate solution, and deionized water.

6. The preparation method of an oil displacement agent based on sheet-like particulate materials according to claim 1, characterized in that, The drying conditions are 8 - 24 h at 25 - 70 °C.

7. An oil displacement agent based on sheet-like particulate materials, the oil displacement agent is prepared by the method according to any one of claims 1 - 6, and the oil displacement agent includes amphiphilic graphene-like nanosheets, characterized in that, The amphiphilic graphene-like nanosheets include: graphene-like nanosheet synthesis raw materials and alkylamine monomers, wherein the mass ratio of the graphene-like nanosheet synthesis raw materials to the alkylamine monomers is 1:1 - 100:1; the graphene-like nanosheet raw materials include but are not limited to any one of glucose, mannose, glutamic acid, citric acid, lignin, and ethylenediamine; The alkylamine monomers include but are not limited to any one of heptylamine, dodecylamine, hexadecylamine, and octadecylamine.

8. The oil displacement agent based on sheet-like particulate materials according to claim 7, characterized in that, The oil displacement agent further includes an amphiphilic graphene-like nanosheet dispersion system; The amphiphilic graphene-like nanoplatelet dispersion system includes a surfactant, wherein the amphiphilic graphene-like nanoplatelets are 0.05 - 1.0 wt%, and the surfactant concentration is 0.0 - 3.0 wt%.

9. The oil displacement agent based on sheet-like particulate material according to claim 7, wherein, the amphiphilic graphene-like nanoplatelets are in a sheet-like structure and include lipophilic groups and hydrophilic groups; the size of the amphiphilic graphene-like nanoplatelets ranges from 30 nm to 10 μm.

10. The oil displacement agent based on sheet-like particulate material according to claim 7, wherein, the amphiphilic graphene-like nanoplatelets can be orderly arranged at the water / oil interface to form a Pickering emulsion.

11. The oil displacement agent based on sheet-like particulate material according to claim 8, wherein, the surfactant includes but is not limited to any one of petroleum sulfonate, heavy alkylbenzene sulfonate, and betaine.

12. The application of the oil displacement agent based on sheet-like particulate material prepared by the method according to any one of claims 1 - 6 or the oil displacement agent based on sheet-like particulate material according to any one of claims 7 - 11, wherein, the application of the oil displacement agent in enhancing oil recovery by chemical flooding.

13. The application of the oil displacement agent based on sheet-like particulate material according to claim 12, wherein, the oil displacement agent is applied in the fields of Pickering emulsion, interfacial polymerization, interfacial catalysis, and enhanced oil recovery.

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