A composite nanoparticle foam oil displacement system, and a preparation method and application thereof

Abstract

The application discloses a composite nanoparticle foam oil displacement system, a preparation method and application thereof. A low-cost nano calcium carbonate is selected as a carrier core, and a silicon dioxide is coated on the surface of the nano calcium carbonate to form a CaCO3@SiO2 core-shell structure composite nanomaterial containing a large number of modifiable hydroxyl groups on the surface. A silane coupling agent containing an alkoxy group is used to modify the CaCO3@SiO2 core-shell structure composite nanomaterial to obtain a nanoparticle containing an alkoxy group on the surface, and the nanoparticle can be reacted with commercially available cationic polyacrylamide to overcome the instability of an existing foam oil displacement system.

Description

Technical Field

[0001] This invention relates to a composite nanoparticle foam oil displacement system, its preparation method, and its application. Background Technology

[0002] In oil extraction, injecting air and foam into the formation for oil displacement (referred to as air foam flooding) is a promising method for enhancing oil recovery in tertiary oil recovery. It can be used as a secondary or tertiary oil recovery method. As a widely used oilfield enhancement technology, the stability of the foam flooding system is a key factor in its effectiveness. In foam preparation, foam stabilizers are additives used to prolong and stabilize foam, maintaining its long-term performance and increasing the strength of the finished product. For products with unstable and easily collapsed bubbles, they can delay the bubble half-life. However, existing foam stabilizers generally have poor foam stabilization performance, and their application in foam can further affect the temperature resistance and oil resistance of the foam fluid. Summary of the Invention

[0003] In order to at least partially solve the above-mentioned technical problems existing in the prior art, the present invention provides a composite nanoparticle foam oil displacement system, its preparation method and application.

[0004] As one aspect of the present invention, a method for preparing a composite nanoparticle foam oil displacement system is provided, the method comprising the following steps:

[0005] S1. Preparation of core-shell silica-coated calcium carbonate nanoparticles (CaCO3@SiO2)

[0006] Ethanol and deionized water were added to calcium carbonate powder and heated to a set temperature. Ammonia was added while stirring. After the temperature of the mixture stabilized, tetraethyl orthosilicate solution was added and reacted at a constant temperature. After cooling, the mixture was filtered, the filter cake was washed, and vacuum dried to obtain core-shell silica-coated calcium carbonate nanoparticles CaCO3@SiO2.

[0007] S2. Preparation of CaCO3@SiO2 nanoparticles containing epoxy groups

[0008] A silane coupling agent containing epoxy groups was added to the core-shell silica-coated calcium carbonate nanoparticles CaCO3@SiO2 prepared in S1. After mixing at a constant temperature, CaCO3@SiO2 nanoparticles containing epoxy groups were obtained.

[0009] S3. Preparation of cationic polyacrylamide grafted nanoparticles

[0010] Using water as a solvent, under stirring conditions, MoO3 and H2O2 were added to CaCO3@SiO2 nanoparticles containing epoxy groups prepared by S2, heated and mixed, cationic polyacrylamide was added to the mixture, and the reaction was carried out at a constant temperature to obtain nanoparticles modified by cationic polyacrylamide grafting.

[0011] S4. Preparation of composite nanoparticle foam oil displacement system

[0012] Under stirring conditions, nanoparticles modified with cationic polyacrylamide prepared by S3 and an anti-swelling agent were added sequentially to the foaming agent to obtain a composite nanoparticle foam oil displacement system.

[0013] In one or more possible embodiments, in S1, the particle size of the calcium carbonate powder is 50-60 nm.

[0014] In one or more possible embodiments, in S1, the isothermal reaction temperature is 40–80°C, and the isothermal reaction time is 4–10 h.

[0015] In one or more possible embodiments, in S1, the mass ratio of the calcium carbonate powder, the ethanol, the deionized water, the ammonia water, and the tetraethyl orthosilicate is 1:150:50:(50-80):(1.2-2.4).

[0016] In one or more possible embodiments, in S2, the mass ratio of the core-shell structured silica-coated calcium carbonate nanoparticles CaCO3@SiO2 to the epoxy-containing silane coupling agent is 1:(0.5-2.4), and the stirring speed is 1000-3000 r / min.

[0017] In one or more possible embodiments, in S3, the cationic polyacrylamide has a molecular weight of 8 million to 12 million.

[0018] In one or more possible embodiments, in S3, the mass ratio of the epoxy-containing CaCO3@SiO2 nanoparticles, the MoO3, the H2O2, the cationic polyacrylamide, and the water is: 1:(0.2-0.4):(1.8-2.4):(0.1-0.6):(80-120).

[0019] In one or more possible embodiments, in S3, the stirring rate is 1000–3000 r / min.

[0020] In one or more possible embodiments, in S4, the foaming agent is selected from one or more of tetraethylene glycol monododecyl ether, octylamidopropyl betaine, sodium stearoyl lactylate, or sodium dodecyl sulfate and sodium α-olefin sulfonate.

[0021] In one or more possible embodiments, in S4, the set rotation speed is 7000-9000 r / min, and the stirring time is 10-15 min.

[0022] As another aspect of the present invention, a composite nanoparticle foam oil displacement system is provided, which is prepared by the method described above.

[0023] As another aspect of the present invention, the application of the above-mentioned composite nanoparticle foam flooding system in foam flooding is discussed.

[0024] The beneficial effects of the above-mentioned technical solutions provided in the embodiments of this application include at least the following:

[0025] This invention discloses a method for preparing a composite nanoparticle foam oil displacement system. Guided by the principles of foam stability factors and the competitive adsorption and distribution of surfactants at different interfaces, it synthesizes nanoparticles with a CaCO3 core coated with SiO2. Leveraging the abundant silanol groups on the surface of the CaCO3@SiO2 nanoparticles, these nanoparticles are grafted with hyperbranched molecules possessing different functional groups, generating a nanoparticle-hyperbranched polymer with strong foam-stabilizing properties. The nanoparticles enhance the toughness and strength of the foam liquid film, while the hyperbranched molecules bind and encapsulate the liquid phase, forming a temperature-resistant and oil-resistant nanoparticle-hyperbranched polymer foam oil displacement fluid.

[0026] The composite nanoparticle foam flooding system prepared in this embodiment of the invention can improve foam stability and, when used in foam flooding, can further improve oil recovery.

[0027] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0028] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0029] Figure 1 This is a scanning electron microscope image of the core-shell silica-coated calcium carbonate nanoparticles in Example 1.

[0030] Figure 2 A reaction mechanism diagram for obtaining epoxy-containing CaCO3@SiO2 nanoparticles by reacting core-shell silica-coated calcium carbonate nanoparticles with γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH-560).

[0031] Figure 3 This is a scanning electron microscope image of the cationic polyacrylamide grafted and modified composite nanoparticles in Example 1;

[0032] Figure 4 The graphs show the changes in foam volume and half-life of the SDS series foaming fluid as a function of foam stabilizer concentration in Example 1 of this invention. In the graphs, (a) shows the change in foam volume of the foam fluid as a function of foam stabilizer concentration, and (b) shows the change in half-life of the foam fluid as a function of foam stabilizer concentration.

[0033] Figure 5 The graph shows the changes in foam volume and half-life of the AOS series foaming fluid as a function of the concentration of the foam stabilizer in Example 1 of this invention. In the graph, (c) is the change in foam volume of the foam fluid as a function of the concentration of the foam stabilizer, and (d) is the change in half-life of the foam fluid as a function of the concentration of the foam stabilizer. Detailed Implementation

[0034] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0035] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0036] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0037] In the description of this invention, it should be noted that the terms "comprising", "including", "having", "containing", etc., are all open-ended terms, meaning that they include but are not limited to.

[0038] The present invention will be further described below with reference to specific embodiments. The scope of protection of the present invention is not limited by the following embodiments. The main materials involved in the embodiments or preparation examples are all conventional commercially available products.

[0039] Example 1

[0040] Reference Figure 1 , 2 As shown in Figure 3, the composite nanoparticles modified with cationic polyacrylamide in this embodiment were prepared through the following steps:

[0041] S1. Preparation of core-shell structured silica-coated calcium carbonate composite nanoparticles (CaCO3@SiO2)

[0042] Weigh 1.0g of calcium carbonate powder and add it to a three-necked flask. Then add 150g of ethanol and 50g of deionized water to the flask. Heat to 50℃ and add 70g of ammonia water while stirring. After the temperature of the mixture stabilizes, add 1.2g of tetraethyl orthosilicate solution and react at a constant temperature of 50℃ for 10h. After cooling, filter and wash the filter cake three times with distilled water and anhydrous ethanol respectively. Then, vacuum dry at 60℃ for 12h to obtain a core-shell silica-coated nanocomposite material of calcium carbonate.

[0043] S2. Preparation of CaCO3@SiO2 nanoparticles containing epoxy groups

[0044] Weigh 1.0g of core-shell silica-coated calcium carbonate nanoparticles prepared from S1 and add 0.5g of γ-glycidyl etheroxypropyltrimethoxysilane (i.e., "γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH-560)"). After stirring and mixing, epoxy-containing CaCO3@SiO2 composite nanoparticles are obtained.

[0045] S3. Preparation of composite nanoparticles modified with cationic polyacrylamide grafting

[0046] 1.0g of CaCO3@SiO2 nanoparticles containing epoxy groups prepared by S2 were added to 100g of water. During stirring, 0.3g of MoO3 and 2.0g of H2O2 were added. After stirring for a certain period of time, 1.0g of commercially available cationic polyacrylamide was added, and the mixture was reacted at a constant temperature of 60℃ for 8h to obtain nanoparticles modified by cationic polyacrylamide grafting.

[0047] Example 2

[0048] The composite nanoparticles modified with cationic polyacrylamide in this embodiment were prepared through the following steps:

[0049] S1. Preparation of core-shell structured silica-coated calcium carbonate composite nanoparticles (CaCO3@SiO2)

[0050] Weigh 1.0g of calcium carbonate powder and add it to a three-necked flask. Then add 150g of ethanol and 50g of deionized water to the flask and heat to 60℃. While stirring, add 50g of ammonia water. After the temperature of the mixture stabilizes, add 1.8g of tetraethyl orthosilicate solution and react at a constant temperature of 60℃ for 7 hours. After cooling, filter the mixture and wash the filter cake three times with distilled water and anhydrous ethanol, respectively. Then, vacuum dry the mixture at 60℃ for 12 hours to obtain a core-shell silica-coated nanocomposite material of calcium carbonate.

[0051] S2. Preparation of CaCO3@SiO2 nanoparticles containing epoxy groups

[0052] 1.0g of core-shell silica-coated calcium carbonate nanoparticles prepared from S1 were weighed and 1.0g of γ-glycidyl etheroxypropyltrimethoxysilane was added. After stirring and mixing, CaCO3@SiO2 composite nanoparticles containing epoxy groups were obtained.

[0053] S3. Preparation of composite nanoparticles modified with cationic polyacrylamide grafting

[0054] 1.0g of CaCO3@SiO2 nanoparticles containing epoxy groups prepared from S2 were added to 100g of water. During stirring, 0.25g of MoO3 and 1.8g of H2O2 were added. After stirring for a certain period of time, 1.2g of commercially available cationic polyacrylamide was added, and the mixture was reacted at a constant temperature of 60℃ for 8h to obtain nanoparticles modified by cationic polyacrylamide grafting.

[0055] Example 3

[0056] The cationic polyacrylamide-modified composite nanoparticles of this embodiment are prepared through the following steps:

[0057] S1. Preparation of core-shell structured silica-coated calcium carbonate composite nanoparticles (CaCO3@SiO2)

[0058] Weigh 1.0g of calcium carbonate powder and add it to a three-necked flask. Then, add 150g of ethanol and 50g of deionized water to the three-necked flask in sequence. Heat to 50℃ and add 80g of ammonia water under stirring. After the temperature of the mixture stabilizes, add 2.0g of tetraethyl orthosilicate solution and react at a constant temperature of 50℃ for 10h. After cooling, filter and wash the filter cake three times with distilled water and anhydrous ethanol respectively. Then, vacuum dry at 60℃ for 12h to obtain a core-shell silica-coated nanocomposite material of calcium carbonate.

[0059] S2. Preparation of CaCO3@SiO2 nanoparticles containing epoxy groups

[0060] 1.0 g of core-shell silica-coated calcium carbonate nanoparticles prepared from S1 were weighed and 0.8 g of γ-glycidyl etheroxypropyltrimethoxysilane was added. After mixing, CaCO3@SiO2 composite nanoparticles containing epoxy groups were obtained.

[0061] S3. Preparation of composite nanoparticles modified with cationic polyacrylamide grafting

[0062] 1.0g of CaCO3@SiO2 nanoparticles containing epoxy groups prepared by S2 were added to 100g of water. During stirring, 0.3g of MoO3 and 2.0g of H2O2 were added. After stirring for a certain period of time, 1.2g of commercially available cationic polyacrylamide was added. The mixture was reacted at a constant temperature of 60℃ for 8h to obtain nanoparticles modified by cationic polyacrylamide grafting.

[0063] Test 1

[0064] To verify the effect of the composite nanoparticle foam flooding system of the present invention on the foaming volume and half-life of the foaming agent, the following tests were conducted.

[0065] Sodium dodecyl sulfate (SDS) was selected as the foaming agent. Taking the cationic polyacrylamide grafted modified nanoparticles prepared in Example 1 of this invention as an example, foam stabilizers used in various oil fields, such as: oil field foam stabilizer QD-1 type, dodecylamine, oil field foam stabilizer CMC type, triethanolamine, and cationic polyacrylamide grafted modified composite nanoparticles CaCO3@SiO2-CPMA, were selected as parallel control experimental groups. The experimental steps are as follows:

[0066] Pour 100 mL of distilled water into a beaker, and add 0.05%, 0.10%, and 0.20% of the six foam stabilizers mentioned above, respectively. Disperse the foam using ultrasonic vibration for 30 min. Add 0.8% of the compound foaming agent to the beaker, pour the mixture into a high-speed stirring cup, and stir at 8000 r / min for 3 min. Quickly pour the foam into a 1000 mL graduated cylinder and record the foam volume and half-life. The changes in foam volume and half-life of the SDS series foam stabilizer concentration are shown in the curves below. Figure 4 As shown, the data results are recorded in Table 1.

[0067] Table 1. Results of foam stabilization performance test

[0068]

[0069] Combining Table 1 and Figure 4As shown, we can see that the composite nanoparticles CaCO3@SiO2-CPMA grafted with cationic polyacrylamide have the best foam stabilizing properties. At a concentration of 0.10%, it can increase the half-life of the SDS foam system by 2.88 times, reaching 2736s, and has the best foam stabilizing effect. The foam volume is not significantly reduced compared with polymer-based foam stabilizers.

[0070] Test 2

[0071] To verify the effect of the composite nanoparticle foam flooding system of the present invention on the foaming volume and half-life of the foaming agent, the following tests were conducted.

[0072] Sodium α-olefin sulfonate (AOS) was selected as the foaming agent. Taking the cationic polyacrylamide grafted modified nanoparticles prepared in Example 1 of this invention as an example, foam stabilizers used in various oil fields, such as: oil field foam stabilizer QD-1 type, dodecylamine, oil field foam stabilizer CMC type, triethanolamine, and cationic polyacrylamide grafted modified composite nanoparticles CaCO3@SiO2-CPMA, were selected as parallel control experimental groups. The experimental steps are as follows:

[0073] Pour 100 mL of distilled water into a beaker, and add 0.05%, 0.10%, and 0.20% of the six foam stabilizers mentioned above, respectively. Disperse the foam using ultrasonic vibration for 30 min. Add 0.8% of the compound foaming agent to the beaker, pour the mixture into a high-speed stirring cup, and stir at 8000 r / min for 3 min. Quickly pour the foam into a 1000 mL graduated cylinder and record the foam volume and half-life. The foam volume and half-life of the AOS series foaming agents are shown in the curves below. Figure 5 As shown, the data results are recorded in Table 2.

[0074] Table 2 Results of foam stabilization performance test

[0075]

[0076]

[0077] Combine Table 2 and Figure 5 As shown, we can see that the composite nanoparticles CaCO3@SiO2-CPMA grafted with cationic polyacrylamide have the best foam stabilizing properties. At a concentration of 0.10%, it can increase the half-life of the AOS foam system by 3.48 times, reaching 2616s, and has the best foam stabilizing effect. The foam volume is not significantly reduced compared with polymer-based foam stabilizers.

[0078] In summary, the cationic polyacrylamide-grafted modified composite nanoparticles (CaCO3@SiO2-CPAM) prepared in this invention possess cationic properties, exhibiting a certain affinity for anionic foaming agents and allowing them to firmly adsorb onto the surface of the foam liquid film. Furthermore, their supramolecular structure contains numerous hydrophilic groups, and the steric hindrance effect of the molecular chains forms a unique 3D topological structure, exhibiting excellent monodispersity, moderate viscosity, and high chemical activity. Therefore, the inventors believe that the cationic polyacrylamide-grafted modified composite nanoparticles prepared using this invention can enhance the toughness and strength of the foam liquid film, and the binding and encapsulating effect of the organic molecular chains on the liquid phase, resulting in a more stable foam-driven oil-dispatch fluid.

[0079] Although the invention has been described in considerable detail and particularly with regard to several of the described embodiments, it is not intended to limit itself to any of these details or embodiments or any particular embodiment, thereby effectively covering the intended scope of the invention. Furthermore, the invention has been described above with respect to embodiments foreseeable by the inventors in order to provide a useful description, and non-substantial modifications to the invention that have not yet been foreseen may still represent equivalent modifications.

[0080] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0081] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preparing a composite nanoparticle foam oil displacement system, characterized in that, The method includes the following steps: S1. Preparation of core-shell silica-coated calcium carbonate nanoparticles (CaCO3@SiO2) Ethanol and deionized water were added to calcium carbonate powder and heated to a set temperature. Ammonia was added while stirring. After the temperature of the mixture stabilized, tetraethyl orthosilicate solution was added and reacted at a constant temperature. After cooling, the mixture was filtered, the filter cake was washed, and vacuum dried to obtain core-shell silica-coated calcium carbonate nanoparticles CaCO3@SiO2. In S1, the mass ratio of the calcium carbonate powder, the ethanol, the deionized water, the ammonia water, and the tetraethyl orthosilicate is 1:150:50:(50~80):(1.2~2.4); S2. Preparation of CaCO3@SiO2 nanoparticles containing epoxy groups γ-(2,3-epoxypropoxy)propyltrimethoxysilane was added to the core-shell silica-coated calcium carbonate nanoparticles prepared by S1, and the mixture was stirred at a constant temperature to obtain CaCO3@SiO2 nanoparticles containing epoxy groups. In S2, the mass ratio of the core-shell structured silica-coated calcium carbonate nanoparticles CaCO3@SiO2 to the γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 1:(0.5~2.4), and the stirring speed is 1000~3000 r / min; S3. Preparation of cationic polyacrylamide grafted nanoparticles Using water as a solvent, under stirring conditions, MoO3 and H2O2 were added to CaCO3@SiO2 nanoparticles containing epoxy groups prepared by S2, heated and mixed, cationic polyacrylamide was added to the mixture, and the reaction was carried out at a constant temperature to obtain nanoparticles modified by cationic polyacrylamide grafting. In S3, the mass ratio of the CaCO3@SiO2 nanoparticles containing epoxy groups, the MoO3, the H2O2, the cationic polyacrylamide, and the water is: 1:(0.2~0.4):(1.8~2.4):(0.1~0.6):(80~120); S4. Preparation of composite nanoparticle foam oil displacement system Under stirring conditions, nanoparticles modified with cationic polyacrylamide prepared by S3 and an anti-swelling agent were added sequentially to the foaming agent to obtain a composite nanoparticle foam oil displacement system. The foaming agent is selected from one or more of sodium stearoyl lactylate, sodium dodecyl sulfate, and sodium α-olefin sulfonate.

2. The preparation method of the composite nanoparticle foam oil displacement system according to claim 1, characterized in that, In S1, the particle size of the calcium carbonate powder is 50~60nm.

3. The preparation method of the composite nanoparticle foam oil displacement system according to claim 1, characterized in that, In S1, the isothermal reaction temperature is 40~80℃, and the isothermal reaction time is 4~10h.

4. The preparation method of the composite nanoparticle foam flooding system according to claim 1, characterized in that, In S3, the cationic polyacrylamide has a molecular weight of 8 million to 12 million.

5. The preparation method of the composite nanoparticle foam flooding system according to claim 1, characterized in that, In S3, the stirring rate is 1000~3000 r / min.

6. The preparation method of the composite nanoparticle foam flooding system according to claim 1, characterized in that, In S4, the set rotation speed is 7000~9000 r / min, and the stirring time is 10~15 min.

7. A composite nanoparticle foam flooding system, characterized in that, The composite nanoparticle foam oil displacement system is prepared by the preparation method of the composite nanoparticle foam oil displacement system according to any one of claims 1 to 6.

8. The application of the composite nanoparticle foam flooding system as described in claim 7 in foam flooding.

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