Graphene oxide composite oil displacement agent as well as preparation method and application thereof

Abstract

The invention provides a graphene oxide composite oil-displacing agent and a preparation method and application thereof.The graphene oxide composite oil-displacing agent is prepared from poly (3-hydroxytyramine) and graphene oxide, the poly (3-hydroxytyramine) and the graphene oxide are combined through chemical bonds, the preparation method comprises the steps that hydrochloric acid 3-hydroxytyramine and the graphene oxide are subjected to a mixed reaction, and the graphene oxide composite oil-displacing agent is obtained. The obtained composite oil-displacing agent is applied to tertiary oil recovery. The composite oil displacement agent provided by the invention has excellent hydrophilicity, acid and alkali resistance and salt resistance, can form a stable water-in-oil emulsion with crude oil in a wide pH value range or under high salinity, and can improve the stability and viscosity of the emulsion; the emulsifying effect is strong, the emulsifying swept volume can be enlarged, and the application prospect in medium-low permeability oil reservoirs is wide; the preparation method provided by the invention is simple, convenient and high in practicability.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum extraction and relates to an oil displacing agent, in particular to a graphene oxide composite oil displacing agent and a preparation method and application thereof. Background Art

[0002] As oil fields gradually enter the high water content and ultra-high water content period, the difficulty of stable production gradually increases, and further improving the recovery rate has become an urgent need for oil field exploitation. Chemical flooding can significantly improve the viscous fingering and phase flow of reservoir fluids, and expand the oil displacement area, thereby improving the recovery rate. However, the oil well environment is complex, and traditional polymer oil displacement agents generally have poor salt resistance, which causes their emulsification properties to deteriorate with changes in pH or salinity, thereby reducing oil displacement efficiency. In comparison, nanoparticle oil displacement agents can avoid the above problems. It forms an oil-water interface layer with strong mechanical properties through irreversible adsorption at the oil-water interface, thereby improving the stability of the emulsion in harsh environments such as high temperature, high pressure, high shear rate and high salinity. In addition, compared with polymer oil displacement agents, nanoparticles have the advantages of low dosage, low environmental pollution and good emulsion stability when used in emulsion preparation.

[0003] CN106433593A discloses a method for preparing a graphene nano oil-displacing agent, which comprises mixing graphene oxide with a polymer and a reducing agent, stirring and mixing the mixture evenly, and cooling and drying the mixture to obtain the oil-displacing agent. The oil-displacing agent has temperature adaptability, and hydrophilic graphene oxide can be converted into hydrophobic graphene by utilizing the high temperature of the formation during the oil-displacing process, thereby improving the oil-displacing efficiency.

[0004] CN114058342A discloses a modified graphene oxide nanosheet tackifier, an oil displacement polymer system and its application and a reservoir oil displacement method. The tackifier is a graphene oxide nanosheet grafted with a small molecule surfactant. The tackifier is combined with an oil displacement polymer to obtain an oil displacement polymer system, which increases the viscosity of the oil displacement polymer, improves the viscosity-increasing efficiency, and thus increases the crude oil recovery rate. The above two oil displacement agents need to be compounded with polymers, which affects the oil displacement efficiency of the oil displacement agent, and the compounded use often results in the problem of poor stability of the emulsion formed.

[0005] CN115717064A discloses a graphene oxide-carbon nanotube composite oil-displacing agent and its application. The composite oil-displacing agent is a sheet-like-fibrous composite structure formed by the composite of graphene oxide and carbon nanotubes. The composite oil-displacing agent mainly exerts its effect by utilizing its structural characteristics, reducing interfacial tension through adsorption, thereby increasing oil recovery, but its emulsification ability for crude oil is very limited.

[0006] Therefore, in view of the shortcomings of the prior art, it is necessary to provide a graphene oxide composite oil-displacing agent and a preparation method and application thereof. Summary of the invention

[0007] The purpose of the present invention is to provide a graphene oxide composite oil-displacing agent and a preparation method and application thereof, which can solve the problem of poor stability of a single nanoparticle or a nanoparticle and polymer composite oil-displacing system, and improve acid, alkali and salt resistance, thereby improving oil displacement efficiency.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a graphene oxide composite oil-displacing agent, wherein the graphene oxide composite oil-displacing agent comprises poly 3-hydroxytyramine and graphene oxide; the poly 3-hydroxytyramine and graphene oxide are chemically bonded.

[0010] The composite oil-displacing agent provided by the present invention synthesizes zero-dimensional poly 3-hydroxytyramine nanoparticles on the surface of graphene oxide nanosheets, the amino groups contained in 3-hydroxytyramine react with the carboxyl groups and epoxy groups on the surface of graphene oxide to form CN chemical bonds, the graphene oxide and crude oil are adsorbed on the oil-water interface through π-π interaction, a three-dimensional barrier is formed at the oil-water interface, droplet aggregation is hindered, and the strength of the composite film at the oil-water interface is further increased through the synergistic effect of 3-hydroxytyramine and graphene oxide, a stable water-in-oil emulsion is formed with crude oil, the emulsification ability and emulsion stability of the composite oil-displacing agent are improved, and efficient oil displacement and expanded emulsification are achieved.

[0011] In a second aspect, the present invention provides a method for preparing the graphene oxide composite oil-displacing agent as described in the first aspect, the preparation method comprising the following steps:

[0012] The 3-hydroxytyramine hydrochloride and graphene oxide are mixed and reacted to obtain the graphene oxide composite oil displacement agent.

[0013] The preparation method provided by the invention can controllably synthesize zero-dimensional poly-3-hydroxytyramine nanoparticles on the surface of graphene oxide, and the method is simple and has strong applicability.

[0014] Preferably, the mass ratio of 3-hydroxytyramine hydrochloride to graphene oxide is 1:(0.2-5), for example, it can be 1:0.2, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 1:(0.5-1.5).

[0015] Preferably, the pH of the reaction is 5-11, for example, 5, 6, 7, 8, 9, 10 or 11, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 6-9.

[0016] Preferably, the reaction temperature is 10-75°C, for example, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C or 75°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the reaction time is 1-48 h, for example, 1 h, 5 h, 10 h, 15 h, 20 h, 25 h, 30 h, 35 h, 40 h, 45 h or 48 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 12-24 h.

[0018] Preferably, the reaction is followed by solid-liquid separation and purification.

[0019] As a preferred technical solution of the preparation method provided by the present invention, the preparation method comprises the following steps:

[0020] 3-Hydroxytyramine hydrochloride and graphene oxide are mixed in a mass ratio of 1:(0.2-5), reacted for 1-48 hours under the conditions of pH 5-11 and temperature 10-75° C., and then solid-liquid separation and purification are performed to obtain the graphene oxide composite oil-displacing agent.

[0021] In a third aspect, the present invention provides an application of the graphene oxide composite oil-displacing agent as described in the first aspect, wherein the graphene oxide composite oil-displacing agent is applied to tertiary oil recovery.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The composite oil-displacing agent provided by the present invention has excellent hydrophilicity, acid and alkali resistance and salt resistance, and can form a stable water-in-oil emulsion with crude oil in a wide pH range or at high salinity, thereby improving the stability and viscosity of the emulsion; it has a strong emulsifying effect, can expand the emulsified swept volume, and has broad application prospects in medium and low permeability oil reservoirs; the preparation method provided by the present invention is simple and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a transmission electron microscope image of the graphene oxide composite oil-displacing agent provided in Example 1 of the present invention.

[0025] Figure 2 This is a transmission electron microscope image of the graphene oxide composite oil-displacing agent provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0027] Example 1

[0028] This embodiment provides a graphene oxide composite oil-displacing agent, and the preparation method of the graphene oxide composite oil-displacing agent comprises the following steps:

[0029] 0.5 g of 3-hydroxytyramine hydrochloride was dissolved in 100 mL of water, and then mixed with 100 mL of aqueous solution containing 0.1 g of graphene oxide, and reacted at 45°C for 12 h. The pH of the solution was controlled to be 7.5 during the reaction. After the reaction, solid-liquid separation was performed, and the product was rinsed with water and ethanol several times to remove the residual unreacted components, and then freeze-dried to obtain a graphene oxide composite oil-displacing agent.

[0030] The transmission electron microscopy image of the graphene oxide composite oil displacement agent prepared in this example is as follows Figure 1 and Figure 2 As shown in the figure, it can be seen that the oil-displacing agent prepared by the present invention is a sheet-like nano material.

[0031] The graphene oxide composite oil-displacing agent prepared in this embodiment is prepared into a dispersion with formation water, the concentration of the oil-displacing agent in the dispersion is 0.009wt%, and the dispersion is mixed with Xinjiang crude oil at a certain liquid-oil volume ratio, the pH of Xinjiang crude oil is 7.8, the salinity is 9993ppm, the liquid-oil volume ratio is 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, 78°C constant temperature for 1h, and then dispersed for 1min with an IKA homogenizer to observe the oil-water emulsification and emulsion stability. Below the liquid-oil volume ratio of 7:3, oil and water can emulsify to form a stable oil-in-water emulsion. The results are listed in Table 1.

[0032] Example 2

[0033] This embodiment provides a graphene oxide composite oil-displacing agent, and the preparation method of the graphene oxide composite oil-displacing agent comprises the following steps:

[0034] 0.5 g of 3-hydroxytyramine hydrochloride was dissolved in 100 mL of water, and then mixed with 100 mL of aqueous solution containing 0.1 g of graphene oxide, and reacted at 75°C for 12 h. The pH of the solution was controlled to be 7.5 during the reaction. After the reaction, solid-liquid separation was performed, and the product was rinsed with water and ethanol several times to remove residual unreacted components, and then freeze-dried to obtain a graphene oxide composite oil-displacing agent.

[0035] The graphene oxide composite oil-displacing agent prepared in this embodiment is prepared into a dispersion with formation water, the concentration of the oil-displacing agent in the dispersion is 0.005wt%, and the dispersion is mixed with Changqing crude oil at a certain liquid-oil volume ratio, the pH of Changqing crude oil is 7.3, the salinity is 32000ppm, the liquid-oil volume ratio is 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, 55°C constant temperature for 1h, and then dispersed with an IKA homogenizer for 1min to observe the oil-water emulsification and emulsion stability. Below the liquid-oil volume ratio of 7:3, oil and water can emulsify to form a stable oil-in-water emulsion. The results are listed in Table 1.

[0036] Example 3

[0037] This embodiment provides a graphene oxide composite oil-displacing agent, and the preparation method of the graphene oxide composite oil-displacing agent comprises the following steps:

[0038] 0.5 g of 3-hydroxytyramine hydrochloride was dissolved in 100 mL of water, and then mixed with 100 mL of aqueous solution containing 0.1 g of graphene oxide, and reacted at 75°C for 24 h. The pH of the solution was controlled to be 7.5 during the reaction. After the reaction, solid-liquid separation was performed, and the product was rinsed with water and ethanol several times to remove the residual unreacted components, and then freeze-dried to obtain a graphene oxide composite oil-displacing agent.

[0039] The graphene oxide composite oil-displacing agent prepared in this embodiment is prepared into a dispersion with formation water, the concentration of the oil-displacing agent in the dispersion is 0.015wt%, and the dispersion is mixed with Jilin crude oil at a certain liquid-oil volume ratio, the pH of Jilin crude oil is 7.1, the salinity is 6631ppm, the liquid-oil volume ratio is 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, 55°C constant temperature for 1h, and then dispersed for 1min with an IKA homogenizer to observe the oil-water emulsification and emulsion stability. Below the liquid-oil volume ratio of 8:2, oil and water can emulsify to form a stable oil-in-water emulsion, and the maximum water content can reach 80%. The results are listed in Table 1.

[0040] Table 1

[0041] Liquid to oil volume ratio Example 1 Example 2 Example 3 1:9 No phase separation No phase separation No phase separation 2:8 No phase separation No phase separation No phase separation 3:7 No phase separation No phase separation No phase separation 4:6 No phase separation No phase separation No phase separation 5:5 No phase separation No phase separation No phase separation 6:4 No phase separation No phase separation No phase separation 7:3 No phase separation No phase separation No phase separation 8:2 Phase separation Phase separation No phase separation 9:1 Phase separation Phase separation Phase separation

[0042] Example 4

[0043] This embodiment provides a graphene oxide composite oil-displacing agent, and the preparation method of the graphene oxide composite oil-displacing agent comprises the following steps:

[0044] 0.5 g of 3-hydroxytyramine hydrochloride was dissolved in 100 mL of water, and then mixed with 100 mL of aqueous solution containing 0.5 g of graphene oxide, and reacted at 45° C. for 20 h. The pH of the solution was controlled to be 7 during the reaction. After the reaction, solid-liquid separation was performed, and the product was rinsed with water and ethanol for multiple times to remove residual unreacted components, and then freeze-dried to obtain a graphene oxide composite oil-displacing agent.

[0045] Example 5

[0046] This embodiment provides a graphene oxide composite oil-displacing agent, and the preparation method of the graphene oxide composite oil-displacing agent comprises the following steps:

[0047] 0.5 g of 3-hydroxytyramine hydrochloride was dissolved in 100 mL of water, and then mixed with 100 mL of aqueous solution containing 0.25 g of graphene oxide, and reacted at 45°C for 20 h. The pH of the solution was controlled to be 6 during the reaction. After the reaction, solid-liquid separation was performed, and the product was rinsed with water and ethanol for multiple times to remove residual unreacted components, and then freeze-dried to obtain a graphene oxide composite oil-displacing agent.

[0048] Example 6

[0049] This embodiment provides a graphene oxide composite oil-displacing agent, and the preparation method of the graphene oxide composite oil-displacing agent comprises the following steps:

[0050] 0.5 g of 3-hydroxytyramine hydrochloride was dissolved in 100 mL of water, and then mixed with 100 mL of aqueous solution containing 0.75 g of graphene oxide, and reacted at 45°C for 20 h. The pH of the solution was controlled to be 9 during the reaction. After the reaction, solid-liquid separation was performed, and the product was rinsed with water and ethanol for multiple times to remove residual unreacted components, and then freeze-dried to obtain a graphene oxide composite oil-displacing agent.

[0051] Example 7

[0052] This embodiment provides a graphene oxide composite oil-displacing agent, and the preparation method of the graphene oxide composite oil-displacing agent comprises the following steps:

[0053] 0.5 g of 3-hydroxytyramine hydrochloride was dissolved in 100 mL of water, and then mixed with 100 mL of aqueous solution containing 2.5 g of graphene oxide, and reacted at 10°C for 48 h. The pH of the solution was controlled to be 11 during the reaction. After the reaction, solid-liquid separation was performed, and the product was rinsed with water and ethanol several times to remove the residual unreacted components, and then freeze-dried to obtain a graphene oxide composite oil-displacing agent.

[0054] Example 8

[0055] This embodiment provides a graphene oxide composite oil-displacing agent, and the preparation method of the graphene oxide composite oil-displacing agent comprises the following steps:

[0056] 0.5 g of 3-hydroxytyramine hydrochloride was dissolved in 100 mL of water, and then mixed with 100 mL of aqueous solution containing 0.1 g of graphene oxide, and reacted at 75° C. for 1 h. The pH of the solution was controlled to be 5 during the reaction. After the reaction, solid-liquid separation was performed, and the product was rinsed with water and ethanol for multiple times to remove residual unreacted components, and then freeze-dried to obtain a graphene oxide composite oil-displacing agent.

[0057] Example 9

[0058] This embodiment provides a graphene oxide composite oil-displacing agent. Compared with Example 4, the pH value during the reaction is controlled to be 4, and the rest is the same as Example 4.

[0059] Example 10

[0060] This embodiment provides a graphene oxide composite oil-displacing agent. Compared with Example 4, the pH value during the reaction is controlled to be 12, and the rest is the same as Example 4.

[0061] Embodiment 11

[0062] This embodiment provides a graphene oxide composite oil-displacing agent. Compared with Embodiment 4, the temperature during the reaction is controlled to be 5° C., and the rest is the same as Embodiment 1.

[0063] Example 12

[0064] This embodiment provides a graphene oxide composite oil-displacing agent. Compared with Embodiment 4, the temperature during the reaction is controlled to be 80° C., and the rest is the same as Embodiment 1.

[0065] Comparative Example 1

[0066] This comparative example provides a graphene oxide oil-displacing agent, wherein the graphene oxide oil-displacing agent comprises graphene oxide.

[0067] The graphene oxide composite oil-displacing agent prepared in Examples 4-12 and Comparative Example 1 was prepared into a dispersion with formation water, the concentration of the oil-displacing agent in the dispersion was 0.005wt%, and the dispersion was mixed with Changqing crude oil at a certain liquid-oil volume ratio, the pH of Changqing crude oil was 7.3, the salinity was 32000ppm, the liquid-oil volume ratio was 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, respectively, at 55°C for 1h, and then dispersed with an IKA homogenizer for 1min, and the oil-water emulsification and emulsion stability were observed. The results are listed in Table 2.

[0068] Table 2

[0069] Maximum liquid-to-oil volume ratio of emulsification Whether phase separation Example 4 7:3 No phase separation Example 5 7:3 No phase separation Example 6 7:3 No phase separation Example 7 6:4 No phase separation Example 8 6:4 No phase separation Example 9 5:5 No phase separation Example 10 5:5 No phase separation Embodiment 11 5:5 No phase separation Example 12 5:5 No phase separation Comparative Example 1 4:6 No phase separation

[0070] It can be seen from Table 1 and Table 2 that the composite oil-displacing agent provided in Examples 1-8 of the present invention can emulsify crude oil with high mineralization. Generally, more oil and less water are required to form an oil-in-water emulsion, that is, the liquid-oil volume ratio is less than 5:5, usually below 3:7, and the composite oil-displacing agent provided by the present invention can increase the emulsified liquid-oil volume ratio to 6:4, especially 7:3, with strong emulsification ability, low concentration of the required oil-displacing agent, small amount, and can form a stable oil-in-water emulsion with high oil displacement efficiency; compared with Example 1, in Examples 9-12, non-preferred reaction pH and temperature of the present invention are used, which reduces the reaction effect of 3-hydroxytyramine hydrochloride and graphene oxide, and the emulsification effect of the obtained composite oil-displacing agent is reduced; in Comparative Example 1, only graphene oxide is used as the oil-displacing agent, and the liquid-oil volume ratio during emulsification is only 4:6, and the emulsification ability is low.

[0071] In summary, the composite oil-displacing agent provided by the present invention has excellent hydrophilicity, acid and alkali resistance and salt resistance, and can form a stable water-in-oil emulsion with crude oil in a wide pH range or at high salinity, thereby improving the stability and viscosity of the emulsion; it has a strong emulsifying effect, can expand the emulsified swept volume, and has broad application prospects in medium and low permeability oil reservoirs; the preparation method provided by the present invention is simple and practical.

[0072] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A graphene oxide composite oil-displacing agent, characterized in that: The graphene oxide composite oil displacement agent comprises poly 3-hydroxytyramine and graphene oxide; the poly 3-hydroxytyramine and graphene oxide are combined with each other by chemical bonds.

2. A method for preparing a graphene oxide composite oil-displacing agent as claimed in claim 1, characterized in that: The preparation method comprises the following steps: The 3-hydroxytyramine hydrochloride and graphene oxide are mixed and reacted to obtain the graphene oxide composite oil displacement agent.

3. The preparation method according to claim 2, characterized in that: The mass ratio of the 3-hydroxytyramine hydrochloride to the graphene oxide is 1:(0.2-5).

4. The preparation method according to claim 2 or 3, characterized in that: The mass ratio of the 3-hydroxytyramine hydrochloride to the graphene oxide is 1:(0.5-1.5).

5. The preparation method according to any one of claims 2 to 4, characterized in that: The pH of the reaction is 5-11, preferably 6-9.

6. The preparation method according to any one of claims 2 to 5, characterized in that: The reaction temperature is 10-75°C.

7. The preparation method according to any one of claims 2 to 6, characterized in that: The reaction time is 1-48h, preferably 12-24h.

8. The preparation method according to any one of claims 2 to 7, characterized in that: After the reaction, solid-liquid separation and purification are carried out in sequence.

9. The preparation method according to any one of claims 2 to 8, characterized in that: The preparation method comprises the following steps: 3-Hydroxytyramine hydrochloride and graphene oxide are mixed in a mass ratio of 1:(0.2-5), reacted for 1-48 hours under the conditions of pH 5-11 and temperature 10-75° C., and then solid-liquid separation and purification are performed to obtain the graphene oxide composite oil-displacing agent.

10. An application of the graphene oxide composite oil-displacing agent as claimed in claim 1, characterized in that: The graphene oxide composite oil-displacing agent is used for tertiary oil recovery.

Images