A nano imbibition displacement agent applicable to shale reservoirs and a preparation method thereof

Abstract

The present invention provides a nano imbibition displacement agent applicable to shale reservoirs and a preparation method thereof. The nano imbibition displacement agent comprises raw materials in the following parts by weight: 30 - 50 parts of sulfonated graphene oxide, 10 - 15 parts of nano silica modified by a silane coupling agent, 10 - 20 parts of water-soluble cellulose ether, 10 - 20 parts of fatty alcohol polyoxyethylene ether, 5 - 8 parts of lower alcohols, and 50 - 80 parts of water. Acidified graphene oxide is prepared by reacting graphene oxide with concentrated nitric acid, and then acyl chloride graphene oxide is prepared by reacting the acidified graphene oxide with thionyl chloride. The acyl chloride graphene oxide then reacts with a sodium aminobenzenesulfonate derivative to obtain the product. The surface sulfonation treatment generates electrostatic repulsion between graphene oxide particles, improves the dispersion ability between particles, avoids agglomeration and flocculation between particles, and improves the recovery rate; the sulfonated graphene oxide and the water-soluble cellulose ether surfactant with a large molecular weight can significantly improve the temperature resistance and salt tolerance of the nano imbibition displacement agent.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield chemistry, and particularly relates to a nano imbibition displacement agent suitable for shale reservoirs and a preparation method thereof. Background Art

[0002] The shale oil reserves in China are as high as 476×10 8 t, and the recoverable reserves are 43.93×10 8 t, showing great development potential. The micro-nano pores and fractures in shale reservoirs are well-developed, which is conducive to the accumulation of shale oil resources. However, the characteristics of strong reservoir sensitivity, high water saturation, and low permeability lead to high mining difficulty and low efficiency. Improving the recovery rate of shale reservoirs is achieved through "fracturing" or "displacement" methods. Horizontal well volume fracturing is the main technology adopted in the initial stage of shale oil development. However, when using horizontal well volume fracturing technology to extract shale oil, there are problems such as the inability to continuously supplement formation energy, rapid decline of initial production, low EUR, and low recovery rate, and a reasonable continuous development method needs to be developed.

[0003] After that, more than 10 "fracturing" or "displacement" methods such as water flooding, agent injection displacement, water injection huff and puff, and refracturing have been studied at home and abroad. Among them, nano imbibition displacement is a new enhanced oil recovery technology. It mainly uses nano materials and the imbibition principle to promote the displacement of crude oil from rock pores and fractures by changing the rock-fluid interface properties. For example, a kind of imbibition displacement agent and its preparation method, and a coupled imbibition fracturing fluid and its application disclosed in Patent CN115895630B, the imbibition displacement agent includes 0.5-10.0% nano silica sol by weight percentage and other predetermined dosage components; a nano magnetic fluid displacement fracturing fluid and its preparation and use method disclosed in Patent CN111253926B, including nano magnetic materials, clear water, dispersants and fracturing fluids.

[0004] The above technologies are nano imbibition displacement agents prepared with nano materials such as nano silica and nano magnetic materials. Under the action of nano materials, the displacement agent can better enter the tiny pores and fractures of low-permeability reservoirs, play a displacement role, and improve the recovery rate of low-permeability reservoirs. However, oil reservoirs are usually complex environments with high temperature, high pressure, and high salinity. Nano silica and nano magnetic materials are prone to agglomeration due to the weakening of hydrogen bonds at high temperature or the compression of the double electric layer in a high ionic strength environment, resulting in an increase in size, making it difficult for the displacement agent to enter tiny pores and fractures and causing a decline in the recovery rate.

[0005] Therefore, it is of great significance to develop a nano imbibition displacement agent with long-term stability in a complex environment of high temperature, high pressure, and high salinity. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a nano-infiltration displacement agent suitable for shale reservoirs and a preparation method thereof. In the nano-infiltration displacement agent, sulfonated graphene oxide is a graphene oxide with a sulfonated surface. After sulfonation, electrostatic repulsion is generated between the graphene oxide particles, improving the dispersion ability between the particles, avoiding agglomeration and flocculation between the particles, and increasing the recovery rate. When sulfonated graphene oxide is used in combination with a water-soluble cellulose ether surfactant with a large molecular weight, the temperature and salt resistance of the nano-infiltration displacement agent can be significantly improved.

[0007] To achieve the above object, the following technical solutions are adopted:

[0008] A nano-infiltration displacement agent suitable for shale reservoirs comprises the following raw materials in parts by weight: 30-50 parts of sulfonated graphene oxide, 10-15 parts of nano-silica modified by a silane coupling agent, 10-20 parts of water-soluble cellulose ether, 10-20 parts of fatty alcohol polyoxyethylene ether, 5-8 parts of lower alcohols, and 50-80 parts of water. The sulfonated graphene oxide is prepared by reacting graphene oxide with concentrated nitric acid to obtain acidified graphene oxide, then reacting the acidified graphene oxide with thionyl chloride to obtain acyl chloride graphene oxide, and then reacting the acyl chloride graphene oxide with an aminobenzenesulfonate derivative.

[0009] The graphene oxide has a sheet diameter of 50-200 nm and a thickness of 0.8-3 nm.

[0010] Graphene oxide is a planar two-dimensional structure material composed of carbon atoms. When passing through pore throats, the bridging blockage between graphene oxide particles causes blockage of the pore throats, increasing the local resistance, forcing subsequent displacement to enter other pores, expanding the swept volume, and increasing the recovery rate. Also, due to its high surface activity, specific surface area, and "aspect ratio" (lateral dimension / thickness), it can better adsorb on the rock wall, improving and even reversing the wettability of the rock surface, making it easier for crude oil to detach from the rock wall surface. By sulfonating its surface, electrostatic repulsion is generated between the graphene oxide particles, improving the dispersion ability between the particles and avoiding agglomeration and flocculation between the particles.

[0011] Sulfonation treatment endows graphene oxide with increased ion exchange performance. Salt ions undergo "adsorption and desorption" on the surface of sulfonated graphene oxide. Affected by high temperature, high salinity, and the "aspect ratio" of graphene oxide, the surface charge distribution and osmotic pressure on the surface of graphene oxide are prone to unbalanced changes, leading to aggregation and precipitation. The combined use of a water-soluble cellulose ether surfactant with a large molecular weight can, on the one hand, utilize its steric hindrance effect and electrostatic stabilization to improve the dispersion performance of sulfonated graphene oxide under high temperature and high salinity. On the other hand, it can also cooperate with sulfonated graphene oxide to reduce the oil-water interfacial tension and improve the oil recovery rate. Among them, the dosage of water-soluble cellulose ether relative to sulfonated graphene oxide needs to be strictly controlled. Because water-soluble cellulose ether has a thickening effect, excessive use will cause the viscosity of the oil displacement agent to be too high, making it difficult for sulfonated graphene oxide to exert its small-size advantage, resulting in an imbalance in mobility control. That is, the oil displacement agent flows rapidly along the high-permeability channels and cannot effectively reach the crude oil in the low-permeability regions, leading to a decrease in the oil recovery rate; while too little sulfonated graphene oxide will not significantly improve the dispersion performance under high temperature and high salinity.

[0012] The concentration of the concentrated nitric acid is 55 - 68 wt%, the mass ratio of graphene oxide to concentrated nitric acid is 1:50 - 100, the mass ratio of acidified graphene oxide to thionyl chloride is 1:50 - 75, and the mass ratio of acyl chloride graphene oxide to sodium aminobenzenesulfonate derivative is 1:1.5 - 2.

[0013] The sodium aminobenzenesulfonate derivative is selected from one or a combination of two or more of sodium 2-aminobenzenesulfonate, sodium 3-aminobenzenesulfonate, and sodium 4-aminobenzenesulfonate.

[0014] The weight-average molecular weight of the water-soluble cellulose ether is 100,000 - 300,000, and it is selected from one or a combination of two of hydroxyethyl cellulose and hydroxypropyl cellulose. The water-soluble cellulose ether is a reaction product of alkali cellulose and ethylene oxide or propylene oxide. When the degree of hydroxyalkyl substitution is high, it is a water-soluble polymer with certain surface activity, thickening property, emulsifying property, etc.

[0015] The silane coupling agent-modified nano-silica is prepared by a method including the following steps:

[0016] Take nano-silica and disperse it in the modification solution to mix evenly to obtain a mixed solution. Heat it to the reflux state for reaction. After the reaction is completed, filter, wash, and dry to obtain the silane coupling agent-modified nano-silica.

[0017] The modified liquid is a solution containing 5-8 wt% of a silane coupling agent, and the solvent is an organic solvent. The silane coupling agent is selected from one or a combination of two or more of amino silane coupling agents, hydroxyl silane coupling agents, and mercapto silane coupling agents. The organic solvent is selected from one or a combination of two or more of benzene and toluene. The silane coupling agent is 5-10 wt% of the nano-silica. The average particle size of the nano-silica and the nano-silica is 30-100 nm. The mass fraction of nano-silica in the mixed liquid is 40-60 wt%. The washing is carried out by washing with ethanol 1-3 times. The drying is carried out at 80-100 °C until constant weight.

[0018] The fatty alcohol of the fatty alcohol polyoxyethylene ether has a straight-chain or branched-chain carbon chain length of 8-24, and the polymerization unit number of the polyoxyethylene ether is 8-20.

[0019] Specifically, the sulfonated graphene oxide is prepared by a method including the following steps:

[0020] 1) Take graphene oxide and add it to concentrated nitric acid for acidification, centrifugation, washing, and drying to obtain acidified graphene oxide;

[0021] 2) Add the acidified graphene oxide and thionyl chloride to an organic solvent, mix evenly, and react under heating and stirring conditions. After the reaction is completed, carry out reduced pressure distillation, filtration, and drying to obtain acyl chloride graphene oxide;

[0022] 3) Add the acyl chloride graphene oxide, sodium aminobenzenesulfonate derivative, and acid-binding agent to an organic solvent, mix evenly, and react under heating and stirring conditions. After the reaction is completed, filter, wash, and dry to obtain sulfonated graphene oxide.

[0023] The conditions for the acidification in step 1) are to react at 80-100 °C for 12-24 h. The washing is to wash the centrifuged solid with water 3-5 times, and the drying is to dry at 60-100 °C until constant weight.

[0024] In step 2), the mass ratio of the acidified graphene oxide to the organic solvent is 1:25-50. The organic solvent is selected from one or a combination of two or more of benzene, toluene, chloroform, and carbon tetrachloride. The heating is to raise the temperature to 70-100 °C, and the reaction time is 12-36 h. The reduced pressure distillation is to remove thionyl chloride. The drying is to dry under a vacuum of 0.01-0.08 MPa and at 60-100 °C for 1-3 h.

[0025] In step 3), the mass ratio of the acyl chloride graphene oxide, the acid-binding agent, and the organic solvent is 1: 0.3-0.6: 60-100. The organic solvent is selected from one or a combination of two or more of tetrahydrofuran, acetone, ether, and DMF. The temperature is raised to 40-60 ° C, and the reaction time is 12-36 h. The acid-binding agent is a tertiary amine, including but not limited to at least one of triethylamine, trimethylamine, and tripropylamine. The washing is carried out by washing with water 1-5 times. The drying is carried out at 60-100 ° C until constant weight.

[0026] There is no particular limitation on the lower alcohol, and those commonly used in the art can be used, and it can be selected from one or a combination of two or more of methanol, ethanol, n-propanol, and isopropanol.

[0027] The present invention also provides a preparation method of the above-mentioned nano-infiltration displacement agent suitable for shale reservoirs, including the following steps:

[0028] Mix sulfonated graphene oxide, silane coupling agent-modified nano-silica, water-soluble cellulose ether, fatty alcohol polyoxyethylene ether, lower alcohol, and water evenly to obtain the nano-infiltration displacement agent suitable for shale reservoirs.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] The nano-infiltration displacement agent of the present invention contains a kind of sulfonated graphene oxide. The surface sulfonation treatment generates electrostatic repulsion between the graphene oxide particles, improves the dispersion ability between the particles, avoids the agglomeration and flocculation between the particles, and improves the recovery rate; the sulfonated graphene oxide cooperates with the water-soluble cellulose ether surfactant with a large molecular weight to significantly improve the temperature resistance and salt tolerance of the nano-infiltration displacement agent. Specific Embodiments

[0031] The following further illustrates the present invention in conjunction with specific embodiments, but is not limited to the content in the specification. Unless otherwise specified, the "parts" in the embodiments of the present invention are all parts by weight. The reagents used are all commercially available reagents in the art.

[0032] The graphene oxide has a sheet diameter of 100 nm and a thickness of 1.2 nm, and is purchased from Xianfeng Nano.

[0033] Hydroxypropyl cellulose Klucel G, with a weight average molecular weight of 300,000, is purchased from Nippon Soda.

[0034] Hydroxypropyl cellulose Klucel L, with a weight average molecular weight of 100,000, is purchased from Nippon Soda.

[0035] The nano-silica product number is DK-SiO2-030, and the average particle size is 30 nm, and it is purchased from Beijing Decodaojin Technology Co., Ltd.

[0036] Preparation Examples

[0037] 500 g of nano-silica DK-SiO2-030 was dispersed in 1000 g of a modified liquid prepared by mixing hydroxymethyltriethoxysilane and benzene in a mass ratio of 5:95, and stirred to form a mixed liquid. The temperature was raised to the reflux state and reacted for 24 h. After the reaction, it was filtered, washed with ethanol three times, and dried at 100 °C to constant weight to obtain silane coupling agent-modified nano-silica. Example 1

[0038] 1) 100 g of graphene oxide was added to 10 kg of concentrated nitric acid with a concentration of 68 wt% and acidified at 100 °C for 24 h, centrifuged, washed with water three times for the solid obtained by centrifugation, and dried at 100 °C to constant weight to obtain acidified graphene oxide;

[0039] 2) 100 g of acidified graphene oxide and 5 kg of thionyl chloride were added to 5 kg of benzene and mixed evenly. The temperature was raised to 80 °C and reacted under stirring conditions for 24 h. After the reaction, thionyl chloride was removed by vacuum distillation, filtered, and dried at a vacuum degree of 0.08 MPa and 60 °C to constant weight to obtain acyl chloride-functionalized graphene oxide;

[0040] 3) 100 g of acyl chloride-functionalized graphene oxide, 200 g of sodium 4-aminobenzenesulfonate, and 60 g of triethylamine as an acid-binding agent were added to 10 kg of DMF and mixed evenly. The temperature was raised to 60 °C and reacted under stirring conditions for 24 h. After the reaction, it was filtered, washed with water three times, and dried to obtain sulfonated graphene oxide.

[0041] 4) 50 g of sulfonated graphene oxide, 10 g of the silane coupling agent-modified nano-silica prepared in the preparation example, 10 g of hydroxypropyl cellulose Klucel L, 20 g of fatty alcohol polyoxyethylene ether AEO-8, 8 g of ethanol, and 80 g of water were mixed evenly to obtain the nano-infiltration displacement agent suitable for shale oil reservoirs. Example 2

[0042] The rest was the same as in Example 1, except that in step 4), the amount of hydroxypropyl cellulose was 20 g. Example 3

[0043] The rest was the same as in Example 1, except that in step 4), hydroxypropyl cellulose Klucel G with the same mass was used to replace hydroxypropyl cellulose Klucel L. Example 4

[0044] The rest was the same as in Example 1, except that in step 4), the amount of sulfonated graphene oxide was 40 g. Example 5

[0045] 1) Take 100 g of graphene oxide and add it to 10 kg of concentrated nitric acid with a concentration of 55 wt%. Acidify it at 100 °C for 24 h, centrifuge, wash the centrifuged solid with water 3 times, and dry it at 100 °C to constant weight to obtain acidified graphene oxide;

[0046] 2) Add 100 g of acidified graphene oxide and 5 kg of thionyl chloride to 5 kg of benzene, mix evenly, raise the temperature to 80 °C, and react under stirring conditions for 24 h. After the reaction, distill off thionyl chloride under reduced pressure, filter, and dry it at a vacuum degree of 0.08 MPa and 60 °C to constant weight to obtain acyl chloride graphene oxide;

[0047] 3) Add 100 g of acyl chloride graphene oxide, 150 g of sodium 3-aminobenzenesulfonate, and 60 g of triethylamine as an acid-binding agent to 10 kg of DMF, mix evenly, raise the temperature to 60 °C, and react under stirring conditions for 24 h. After the reaction, filter, wash with water 3 times, and dry to obtain sulfonated graphene oxide.

[0048] 4) Mix 30 g of sulfonated graphene oxide, 15 g of the prepared silane coupling agent-modified nano-silica, 10 g of hydroxypropyl cellulose Klucel L, 10 g of fatty alcohol polyoxyethylene ether AEO-8, 5 g of ethanol, and 80 g of water evenly to obtain the nano-infiltration displacement agent suitable for shale oil reservoirs. Example 6

[0049] The rest is the same as in Example 1, except that in step 3), 100 g of acyl chloride graphene oxide, 150 g of sodium 4-aminobenzenesulfonate, and 30 g of triethylamine as an acid-binding agent are added to 10 kg of DMF, mix evenly, raise the temperature to 60 °C, and react under stirring conditions for 24 h. After the reaction, filter, wash with water 3 times, and dry to obtain sulfonated graphene oxide. Comparative Example 1

[0050] The rest is the same as in Example 1, except that in step 4), the dosage of hydroxypropyl cellulose Klucel L is 25 g. Comparative Example 2

[0051] The rest is the same as in Example 1, except that in step 4), the dosage of hydroxypropyl cellulose Klucel L is 5 g. Comparative Example 3

[0052] Mix 60 g of the prepared silane coupling agent-modified nano-silica, 10 g of hydroxypropyl cellulose Klucel L, 20 g of fatty alcohol polyoxyethylene ether AEO-8, 8 g of ethanol, and 80 g of water evenly to obtain the nano-infiltration displacement agent suitable for shale oil reservoirs. That is, compared with Example 1, sulfonated graphene oxide is replaced with an equal mass of modified nano-silica. Comparative Example 4

[0053] Mix 50 g of graphene oxide, 10 g of the silane coupling agent - modified nano - silica prepared in the preparation example, 10 g of hydroxypropyl cellulose Klucel L, 20 g of fatty alcohol polyoxyethylene ether AEO - 8, 8 g of ethanol, and 80 g of water uniformly to obtain the nano - imbibition displacement agent applicable to shale reservoirs. That is, compared with Example 1, the graphene oxide is not sulfonated - modified.

[0054] Conduct the following performance tests on the nano - imbibition displacement agents prepared in the above - mentioned examples and comparative examples:

[0055] 1. Temperature and salt tolerance performance: Prepare formation water respectively. The salinity and ion concentration of the formation water are shown in Table 1:

[0056] Table 1 Salinity and ion concentration of formation water

[0057]

[0058] Add the displacement agents prepared in the examples and comparative examples to the formation water to prepare a displacement agent solution with a mass fraction of 0.3%. Heat the displacement agent solution to 150 °C and let it age for 6 days. Measure the apparent viscosity before and after aging with a HAAKE™ Viscotester™ 3 rotational viscometer, shear for 30 min, and the shear rate is 8 s -1 , and calculate the retention rate of the apparent viscosity at each salinity.

[0059] 2. Recovery rate: a. Add the nano - imbibition displacement agent to the simulated formation water (the ion composition of the simulated formation water is shown in Table 2) to prepare a displacement agent solution with a mass concentration of 0.4%. Measure and record the apparent viscosity at 72 °C using the above - mentioned method; b. Saturate water: Evacuate the artificial heterogeneous core (diameter 2.5 cm, length 30 cm, permeability 20×10 -3 μm 2 ), and saturate it with formation water; c. Saturate oil: Saturate with J10022 - H crude oil (viscosity 45.2 mPa·s) at 90 °C, take it out after standing for 24 h, and the original oil saturation is 65%; d. Water - flooding: Water - flood (simulated formation water, displacement rate 0.1 mL / min) until the water cut reaches 98%, and record the recovery rate g at a water cut of 98%; e. Inject the displacement agent: Inject 0.5 PV of the displacement agent solution and then water - flood until the water cut reaches 98%, record the cumulative recovery rate h, and calculate the displacement agent recovery rate i, i = h - g.

[0060] Table 2 Ion composition of simulated formation water

[0061]

[0062] Table 3 Performance test results

[0063]

[0064] Table 3 shows the test results of the performance detection of the nano imbibition displacement agent. From the recovery rate of the displacement agent in the performance test results of Table 3, it can be seen that the recovery rate of the present invention after sulfonation of graphene oxide has increased from 27.6% without sulfonation to more than 40%, indicating that the displacement agent has an excellent function of improving the recovery rate. From the test results of temperature resistance and salt tolerance performance, it can be seen that the viscosity retention rate is high after high salinity and high temperature aging, and there is no significant viscosity reduction, indicating that the displacement agent provided by the present invention has good temperature resistance and salt tolerance performance. From the test results of temperature resistance and salt tolerance performance of the examples and comparative examples, it can be seen that sulfonated graphene oxide has the effect of synergistically improving the temperature resistance and salt tolerance performance of the displacement agent with water-soluble cellulose ether.

[0065] The above detailed description is a specific description of one of the feasible embodiments of the present invention, and this embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or change made without departing from the present invention shall be included within the scope of the technical solution of the present invention.

Claims

1. A nano-infiltration displacement agent applicable to shale oil reservoirs, characterized in that, It comprises raw materials in the following parts by weight: 30-50 parts of sulfonated graphene oxide, 10-15 parts of silane coupling agent-modified nano-silica, 10-20 parts of water-soluble cellulose ether, 10-20 parts of fatty alcohol polyoxyethylene ether, 5-8 parts of lower alcohol, and 50-80 parts of water. The sulfonated graphene oxide is prepared by reacting graphene oxide with concentrated nitric acid to obtain acidified graphene oxide, then reacting the acidified graphene oxide with thionyl chloride to obtain acyl chloride graphene oxide, and then reacting the acyl chloride graphene oxide with an aminobenzenesulfonate derivative; the graphene oxide has a sheet diameter of 50-200 nm and a thickness of 0.8-3 nm; the mass ratio of acyl chloride graphene oxide to aminobenzenesulfonate derivative is 1:1.5-2; the aminobenzenesulfonate derivative is selected from one or a combination of two or more of sodium 2-aminobenzenesulfonate, sodium 3-aminobenzenesulfonate, and sodium 4-aminobenzenesulfonate; the water-soluble cellulose ether has a weight-average molecular weight of 100,000-300,000; the concentration of the concentrated nitric acid is 55-68 wt%, the mass ratio of graphene oxide to concentrated nitric acid is 1:50-100, and the mass ratio of acidified graphene oxide to thionyl chloride is 1:50-75; the water-soluble cellulose ether is selected from one or a combination of two of hydroxyethyl cellulose and hydroxypropyl cellulose.

2. The nano-infiltration displacement agent applicable to shale reservoirs according to claim 1, wherein The water-soluble cellulose ether is selected from one or a combination of two of hydroxyethyl cellulose and hydroxypropyl cellulose; the fatty alcohol of the fatty alcohol polyoxyethylene ether has a straight-chain or branched-chain carbon chain length of 8-24, and the number of polymerization units of the polyoxyethylene ether is 8-20.

3. The nano-infiltration displacement agent applicable to shale reservoirs according to claim 1, wherein The silane coupling agent-modified nano-silica is prepared by a method comprising the following steps: Take nano-silica, disperse it in a modification solution and mix evenly to obtain a mixed solution, heat it to the reflux state for reaction, and after the reaction is completed, filter, wash, and dry to obtain the silane coupling agent-modified nano-silica.

4. The nano-infiltration displacement agent applicable to shale reservoirs according to claim 3, characterized in that, The modification solution is a solution containing 5-8 wt% of a silane coupling agent, and the silane coupling agent is selected from one or a combination of two or more of an amino silane coupling agent, a hydroxy silane coupling agent, and a mercapto silane coupling agent.

5. The nano-infiltration displacement agent applicable to shale oil reservoirs according to claim 3, wherein The silane coupling agent is 5-10 wt% of the nano-silica; the average particle size of the nano-silica is 30-100 nm; the mass fraction of nano-silica in the mixed solution is 40-60 wt%.

6. The nano-infiltration displacement agent applicable to shale oil reservoirs according to claim 1, wherein The sulfonated graphene oxide is prepared by a method comprising the following steps: 1) Take graphene oxide, add it to concentrated nitric acid for acidification, centrifugation, washing, and drying to obtain acidified graphene oxide; 2) Add the acidified graphene oxide and thionyl chloride to an organic solvent, mix evenly, and react under heating and stirring conditions. After the reaction is completed, carry out reduced pressure distillation, filtration, and drying to obtain acyl chloride graphene oxide; 3) Add the acyl chloride graphene oxide, aminobenzenesulfonate derivative, and acid-binding agent to an organic solvent, mix evenly, and react under heating and stirring conditions. After the reaction is completed, filter, wash, and dry to obtain sulfonated graphene oxide.

7. The nano-infiltration displacement agent applicable to shale reservoirs according to claim 6, characterized in that, In step 2), the mass ratio of the acidified graphene oxide to the organic solvent is 1:25 - 50; in step 3), the mass ratio of the acyl chloride graphene oxide, the acid-binding agent, and the organic solvent is 1:0.3 - 0.6:60 - 100.

8. The preparation method of the nano imbibition displacement agent applicable to shale reservoirs according to any one of claims 1-7, characterized in that, It includes the following steps: Mix sulfonated graphene oxide, silane coupling agent-modified nano-silica, water-soluble cellulose ether, fatty alcohol polyoxyethylene ether, lower alcohol, and water evenly to obtain the nano-infiltration displacement agent applicable to shale oil reservoirs.

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