A temperature-sensitive supramolecular host-guest complex in-situ synergistic oil displacement system, a preparation method and application thereof

Abstract

This invention provides a thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system, its preparation method, and its application, belonging to the field of oilfield production technology. First, this invention introduces polymerizable monomers onto the surface of nano-silica to prepare silicon-based nanoparticles with cyclodextrin groups on their surface. Then, using hydrophilic monomers acrylamide and weakly hydrophobic monomers diacetone acrylamide as reactants, a thermosensitive copolymer with terminal amino groups is prepared, and this copolymer is used as a grafted side chain to synthesize a thermosensitive graft polymer. Furthermore, through inclusion, a supramolecular synergistic enhancement system of silicon-based nanoparticles and thermosensitive graft polymer is constructed. This ensures the oil displacement system's high-temperature resistance and strong shear loss resistance while achieving temperature-responsive regulation between hydrophilic and hydrophobic properties at both surface and reservoir temperatures. This meets basic production requirements while improving the reservoir adaptability and practical application range of the oil displacement system in oilfields.

Description

Technical Field

[0001] This invention belongs to the field of oilfield production technology, specifically relating to a temperature-sensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system, its preparation method, and its application. Background Technology

[0002] Chemical flooding is a universal and efficient method to improve oil recovery. It involves injecting chemical agents (such as polymers, surfactants, alkalis or their compound systems) into the reservoir to change the properties of the oil-water-rock interface or the rheological behavior of the fluid, thereby improving the oil recovery rate.

[0003] Polymer-assisted oil recovery (FAOR) primarily involves injecting polymer solutions to improve the water-drive mobility ratio and sweep efficiency through viscosity enhancement. However, commonly used polymers (such as partially hydrolyzed polyacrylamide (HPAM)) experience viscosity shear losses of up to 50%-70% during formulation and injection. Furthermore, they are prone to hydrolysis, degradation, and shear dilution under high-temperature and high-salt conditions. This irreversible system loss leads to a significant decrease in viscosity and reduced sweep efficiency, severely impacting the effectiveness of enhanced oil recovery. Nanoparticle-based FOROR, which disperses nanoparticles in the injected liquid phase to form nanofluids and utilizes the small size effect and interfacial activity of the particles for oil displacement, suffers from difficulties in controlling mobility and interfacial activity, and is prone to functional loss due to aggregation. Adding synergists to the polymer system to construct supramolecular polymer systems through host-guest inclusion, multiple hydrogen bonds, and electrostatic interactions offers a new approach to solving these challenges. If the synergist and polymer undergo supramolecular interaction before reaching the target reservoir, the viscosity of the oil displacement system will increase. At this time, the system will be difficult to inject into the formation or the oil recovery rate will be further reduced. Therefore, more precise and specific system construction and functional design schemes are needed to dynamically control the interaction time and mode between the components in the supramolecular system in order to further meet the reservoir adaptability of the oil displacement system.

[0004] Chinese patent document CN 118146441 A discloses a temperature- and salt-resistant amphiphilic polymer and a supramolecular oil displacement system and its application. This oil displacement system consists of a temperature- and salt-resistant amphiphilic polymer and a β-cyclodextrin polymer. The sulfonic acid groups on the amphiphilic polymer mitigate the problem of reduced solution viscosity caused by electrostatic shielding, and the introduction of benzene ring groups provides certain temperature resistance. Simultaneously, the acrylate functional monomers on the polymer promote hydrogen bond formation, further improving the network structure strength and density. Furthermore, the β-cyclodextrin polymer enhances viscosity by synergistic inclusion in the supramolecular system construction. These functional designs improve the sweep efficiency during crude oil displacement. However, the entire oil displacement system still lacks a stage control mechanism and has poor formation adaptability, making it difficult to meet the enhanced oil recovery requirements of reservoirs under complex conditions.

[0005] Therefore, developing a supramolecular oil displacement system that can adapt to complex high-temperature and high-salinity reservoir environments and has strong resistance to shear loss, and realizing its dynamic synergistic regulation in target reservoir layers, is of great practical significance for the efficient development of oil fields. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system, its preparation method, and its application. First, this invention introduces polymerizable monomers onto the surface of nano-silica to prepare silicon-based nanoparticles with cyclodextrin groups on their surface. Then, using hydrophilic monomers acrylamide and weakly hydrophobic monomers diacetone acrylamide as reactants, a thermosensitive copolymer with terminal amino groups is prepared, and this copolymer is used as a grafted side chain to synthesize a thermosensitive graft polymer. Furthermore, through inclusion bonding, a supramolecular synergistic system of silicon-based nanoparticles and thermosensitive graft polymer is constructed. This ensures the oil displacement system's high-temperature resistance and strong shear loss resistance while achieving temperature-responsive regulation between hydrophilicity and hydrophobicity at both surface and reservoir temperatures. This meets basic production requirements while improving the reservoir adaptability and practical application range of the oil displacement system in oilfields.

[0007] The technical solution of the present invention is as follows:

[0008] This invention provides a thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system, comprising the following components: silicon-based nanoparticles with cyclodextrin groups on their surface and a thermosensitive grafted polymer;

[0009] A method for preparing silicon-based nanoparticles with cyclodextrin groups on their surface, comprising the following steps:

[0010] A1: Add silane coupling agent dropwise to an ethanol aqueous solution, perform hydrolysis reaction, and then adjust the pH to 5.0; add nano-silica, disperse thoroughly, react, centrifuge, wash, and dry to obtain hydrophobic nano-silica;

[0011] A2: Hydrophobic nano-silica is fully dispersed in deionized water, and cyclodextrin-containing polymer monomers and initiator 1 are added. After reaction, centrifugation, washing and drying are performed to obtain silicon-based nanoparticles with cyclodextrin groups on the surface.

[0012] The preparation method of the thermosensitive grafted polymer includes the following steps:

[0013] B1: Acrylamide (AM) and diacetone acrylamide (DAAM) are dissolved in anhydrous methanol, chain transfer agent and initiator 2 are added, the reaction is carried out, and then the product is purified, washed and dried to obtain an amino-terminated thermosensitive copolymer.

[0014] B2: Dissolve sodium polyacrylate (NaPAA) in 2-morpholinoethanesulfonic acid (MES) buffer, adjust the pH to 5.0, add carboxyl activator and activation enhancer, and carry out the reaction; add dropwise a mixture of terminal amino thermosensitive copolymer and 2-morpholinoethanesulfonic acid (MES) buffer, react, then adjust the pH to 6.0, dialysis purification, and freeze-dry to obtain thermosensitive graft polymer.

[0015] According to a preferred embodiment of the present invention, in step A1, the silane coupling agent is one of vinyltrimethoxysilane (KBM-1003) or γ-methacryloxypropyltrimethoxysilane (KH570), preferably γ-methacryloxypropyltrimethoxysilane. The methoxy group contained in KH570 has higher hydrolysis reaction efficiency and provides excellent interfacial compatibility for silica. Therefore, while improving the dispersion stability of nano-silica, it has higher modification efficiency and more stable effects, resulting in synthesized hydrophobic nano-silica with superior performance.

[0016] According to a preferred embodiment of the present invention, in step A1, the volume ratio of ethanol to water in the ethanol-water solution is 5-10:1, preferably 9:1.

[0017] According to a preferred embodiment of the present invention, in step A1, the mass ratio of the silane coupling agent to the volume ratio of the ethanol aqueous solution is 1-3 mg / mL.

[0018] According to a preferred embodiment of the present invention, in step A1, the hydrolysis reaction temperature is room temperature, the hydrolysis reaction time is 20-60 min, and the hydrolysis reaction is carried out under stirring conditions.

[0019] According to a preferred embodiment of the present invention, in step A1, the pH value of the reaction system is adjusted using a hydrochloric acid aqueous solution with a mass concentration of 10-20%.

[0020] According to a preferred embodiment of the present invention, in step A1, the particle size of the nano-silica is 50-500 nm, preferably 100 nm. When the particle size of the nano-silica is too large, there is a significant size difference between it and the thermosensitive graft polymer, the guest component of the supramolecular interaction, which easily leads to phase separation in the subsequent compounding system. In practical applications, chromatographic separation is foreseeable. When the particle size is too small, the nano-silica does not significantly improve the shear resistance of the final oil displacement system, and its effect on enhancing structural properties is limited.

[0021] According to a preferred embodiment of the present invention, in step A1, the mass ratio of nano-silica to silane coupling agent is 50-400:1, preferably 133-200:1, and more preferably 200:1.

[0022] According to a preferred embodiment of the present invention, in step A1, the reaction temperature after adding nano-silica is 60-80°C, the reaction time is 4-8 hours, and the reaction is carried out under reflux and stirring conditions.

[0023] According to a preferred embodiment of the present invention, in step A2, the mass ratio of hydrophobic nano-silica to the volume ratio of deionized water is 0.1-0.5 g / mL.

[0024] According to a preferred embodiment of the present invention, in step A2, the cyclodextrin-containing polymerizing monomer is one of allyl-β-cyclodextrin (Allyl-β-CD) or 6-acryloylethylenediamine-β-cyclodextrin (β-CD-6-EA), preferably allyl-β-cyclodextrin.

[0025] According to a preferred embodiment of the present invention, in step A2, the initiator 1 is one of ammonium persulfate (APS), potassium persulfate (KPS) or cerium ammonium nitrate (CAN), preferably ammonium persulfate.

[0026] According to a preferred embodiment of the present invention, in step A2, the mass ratio of hydrophobic nano-silica, cyclodextrin-containing polymeric monomer, and initiator 1 is 100-400:20-220:1, preferably 100:25-50:1, and more preferably 100:50:1.

[0027] According to a preferred embodiment of the present invention, in step A2, the reaction temperature is 60-80°C, the reaction time is 6-10 hours, and the reaction is carried out under anaerobic, protective gas conditions with stirring. The protective gas is nitrogen or argon.

[0028] According to a preferred embodiment of the present invention, in step B1, the chain transfer agent is one of 2-mercaptoethylamine hydrochloride (AET), mercaptoacetic acid (TGA), isopropanol (IPA) or 3-benzyltrithiopropionic acid (BSPA), preferably 2-mercaptoethylamine hydrochloride.

[0029] According to a preferred embodiment of the present invention, in step B1, the initiator 2 is one of azobisisobutyronitrile (AIBN), dimethyl azobisisobutyrate (AIBME), or azobisisoheptanenitrile (ABVN), preferably azobisisobutyronitrile.

[0030] According to a preferred embodiment of the present invention, in step B1, the mass ratio of acrylamide, diacetone acrylamide, chain transfer agent, and initiator 2 is 100-400:20-100:2-10:1, preferably 250:40-62.5:6.25-10:1, and more preferably 250:62.5:10:1. An excessively high proportion of acrylamide monomer structure on the polymer backbone will cause the material to fail to form a stable structure and dissolve in water, subsequently losing its thickening ability; an excessively high proportion of diacetone acrylamide body structure on the polymer backbone will cause a large number of ketone carbonyl groups to be suspended on the polymer chain, increasing hydrophobicity and resulting in insolubility in solvents.

[0031] According to a preferred embodiment of the present invention, in step B1, the mass ratio of acrylamide to anhydrous methanol is 1:1-10 g / mL, preferably 1:5 g / mL.

[0032] According to a preferred embodiment of the present invention, in step B1, the reaction temperature is 60-80°C, the reaction time is 6-10 hours, and the reaction is carried out under anaerobic, protective gas, and stirring conditions.

[0033] According to a preferred embodiment of the present invention, in step B1, the purification solution is a mixture of diethyl ether and n-hexane, wherein the volume ratio of diethyl ether to n-hexane is 1-5:1, preferably 1:1.

[0034] According to the present invention, taking 2-mercaptoethylamine hydrochloride as a chain transfer agent as an example, the amino-terminated thermosensitive copolymer has the following structure:

[0035]

[0036] According to a preferred embodiment of the present invention, in step B2, the mass ratio of sodium polyacrylate (NaPAA) to the volume ratio of 2-morpholinoethanesulfonic acid (MES) buffer is 0.1-10:100 g / mL, preferably 1:100 g / mL.

[0037] According to a preferred embodiment of the present invention, in step B2, a 10-20% hydrochloric acid aqueous solution is added dropwise to adjust the pH to 5.0.

[0038] According to a preferred embodiment of the present invention, in step B2, the carboxyl activator is one of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl), dicyclohexylcarbodiimide (DCC) or diisopropylcarbodiimide (DIC), preferably 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride.

[0039] According to a preferred embodiment of the present invention, in step B2, the activating enhancer is one of N-hydroxysuccinimide (NHS) or 1-hydroxybenzotriazole (HOBt), preferably N-hydroxysuccinimide.

[0040] According to a preferred embodiment of the present invention, in step B2, the mass ratio of sodium polyacrylate, carboxyl activator, and activation enhancer is 3-10:1-4:1, preferably 4.3-9:1.6-2:1, and more preferably 4.3:1.6:1.

[0041] According to a preferred embodiment of the present invention, in step B2, the reaction conditions after adding the carboxyl activator and the activation enhancer are as follows: stirring at 0-4°C for 10-20 min, and then stirring at room temperature for 40-50 min.

[0042] According to a preferred embodiment of the present invention, in step B2, the mass ratio of the amino-terminated thermosensitive copolymer to the volume ratio of the 2-morpholinoethanesulfonic acid (MES) buffer in the mixture of the amino-terminated thermosensitive copolymer and the 2-morpholinoethanesulfonic acid (MES) buffer is 1-5:200 g / mL, preferably 3:200 g / mL.

[0043] According to a preferred embodiment of the present invention, in step B2, the mass ratio of sodium polyacrylate (NaPAA) to the amino-terminated thermosensitive copolymer is 2-4:1. If the proportion of the amino-terminated thermosensitive copolymer is too low, most of the carboxyl groups cannot undergo amidation with the amino groups, resulting in an extremely low grafting density and making it difficult to impart significant thermosensitive properties to the product. Conversely, a large amount of ungrafted thermosensitive copolymer will remain in the product, leading to a decrease in product purity and requiring additional purification.

[0044] According to a preferred embodiment of the present invention, in step B2, the reaction temperature after adding the mixture of the terminal amino thermosensitive copolymer and 2-morpholinoethanesulfonic acid (MES) buffer is room temperature, the reaction time is 20-30 h, and the reaction is carried out under protective gas and stirring conditions. Preferably, the protective gas is nitrogen or argon.

[0045] According to a preferred embodiment of the present invention, in step B2, the pH is adjusted to 6.0 using a NaOH aqueous solution with a mass concentration of 15-30%.

[0046] According to a preferred embodiment of the present invention, in step B2, the 2-morpholinoethanesulfonic acid (MES) buffer is an aqueous solution of 2-morpholinoethanesulfonic acid (MES) with a concentration of 100 mmol / L and a pH of 5.0. The buffer of the present invention can stabilize the pH of the entire system within a specific, mild acidic range, avoiding sudden drops in local pH caused by uneven acidification, thereby preventing uneven aggregation and precipitation.

[0047] According to the present invention, taking 2-mercaptoethylamine hydrochloride as a chain transfer agent as an example, the thermosensitive graft polymer has the following structure:

[0048]

[0049] According to a preferred embodiment of the present invention, the thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system further includes a PBS buffer solution with a concentration of 0.01 mol / L and a pH of 7.4; the total mass ratio of the silicon-based nanoparticles with cyclodextrin groups on their surface and the thermosensitive grafted polymer to the PBS buffer solution is 10-15 g / L. For supramolecular assembly, a moderately stable dispersion system is more conducive to the diffusion, recognition, and binding of host and guest molecules, rather than complete aggregation or complete separation. The cavity of β-cyclodextrin has the best hydrophobic internal environment near the neutral pH under buffer conditions, which is most conducive to the inclusion of guest molecules through hydrophobic interactions. In addition, the PBS buffer solution can shield the surface charge of the nanoparticles, preventing aggregation or precipitation caused by excessively strong or weak electrostatic repulsion.

[0050] According to a preferred embodiment of the present invention, the mass ratio of silicon-based nanoparticles with cyclodextrin groups on their surface to the thermosensitive grafted polymer is 1:1-2.

[0051] The preparation method of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system includes the following steps:

[0052] Silicon-based nanoparticles with cyclodextrin groups on their surface were dissolved in PBS buffer to obtain mixture 1; thermosensitive grafted polymers were dissolved in PBS buffer at 1-5℃ with stirring to obtain mixture 2; mixture 1 and mixture 2 were mixed and stirred at 1-5℃ for 1-3 hours, the temperature was raised to above the minimum critical co-solution temperature (UCST), stirring was continued for 0.5-2 hours, centrifuged, washed with PBS buffer at 1-5℃, and vacuum dried to obtain a thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system.

[0053] According to a preferred embodiment of the present invention, the volume ratio of PBS buffer in mixture 1 to PBS buffer in mixture 2 is 0.5-4:1, preferably 1:1.

[0054] According to the present invention, the minimum critical eutectic temperature (UCST) above the UCST is preferably 40-60°C, and more preferably 40°C. If the temperature is too high during the pre-inclusion process, the thermosensitive grafted polymer will exhibit a strong inclusion effect with the cyclodextrin groups, resulting in a system with high viscosity, which is detrimental to its dispersion during application. At the temperature of the present invention, the hydrophobic groups of the thermosensitive polymer partially activate the host and guest components, generating a certain strength of inclusion effect, but the resulting system still has good solubility and dispersibility, preventing chromatographic separation after injection into the formation.

[0055] The application of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system in oil displacement.

[0056] According to a preferred embodiment of the present invention, the application method includes the steps of: fully dispersing the temperature-sensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system in a dispersion solvent for use in oil displacement to improve oil recovery. Preferably, the dispersion solvent is oilfield water; the mass ratio of the temperature-sensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system to the volume ratio of the dispersion solvent is 1:(30-80) g / mL.

[0057] The technical features and beneficial effects of this invention are as follows:

[0058] (1) The supramolecular host-guest inclusion in-situ enhanced oil displacement system provided by the present invention has stronger stability. First, solid silicon-based nanoparticles are introduced as the host material of the supramolecular system. After modification with silane coupling agent, polymerizable monomers are introduced onto the surface of nano-silica with hydrophobic properties. After surface modification, the nanoparticles have better compatibility with the guest components of the system. As a solid component, it can maintain a uniform distribution state inside the system, which gives the oil displacement system stronger structural performance. In addition, amide bonds with higher bond energy than carbon-carbon bonds are selected as grafting points during the synthesis of graft polymers. Therefore, compared with the homogeneous oil displacement system, it has higher thermal stability and shear resistance in the target reservoir.

[0059] (2) The supramolecular host-guest inclusion in-situ enhanced oil displacement system provided by this invention has good injection performance under surface temperature conditions. On the one hand, the hydrophilic groups in the diacetone acrylamide side chain grafted onto the polymer backbone form hydrogen bonds with water, causing the side chain to extend. The polymer molecular chain fully expands in water and has good affinity with the surrounding solvent, resulting in good fluidity and solubility of the polymer solution. On the other hand, it does not interact with the supramolecular host below UCST. Therefore, the system exhibits the characteristics of low initial viscosity and good injectability, which can reduce injection pressure, ensure equipment safety, avoid the decrease in injection capacity caused by near-wellbore blockage, and improve sweep uniformity, thereby improving the longitudinal sweep efficiency of heterogeneous reservoirs. At the same time, the low initial viscosity can avoid polymer molecular chain breakage, reduce viscosity loss during injection, and reduce energy consumption and material costs.

[0060] (3) The supramolecular host-guest inclusion in-situ enhanced oil displacement system provided by the present invention has temperature-sensitive response performance. The temperature-sensitive copolymer synthesized by using hydrophilic monomer acrylamide and weakly hydrophobic monomer diacetone acrylamide as the reaction monomers is used as the grafting object. When the reservoir temperature rises to a certain extent after injection into the formation, the hydrogen bonding force between the hydrophilic group and the water molecule weakens, while the hydrophobic association interaction between the hydrophobic groups in diacetone acrylamide is enhanced, which promotes the coiling and aggregation of polymer molecular chains, reduces the distance between molecular chains, and reduces the solubility of the polymer in water, thereby increasing the viscosity of the system. On the other hand, at this time, the weakly hydrophobic monomer in the temperature-sensitive grafted polymer exhibits strong hydrophobicity. The cyclodextrin groups on the surface of the nanoparticles in the system capture the hydrophobic groups in the grafted polymer to form inclusion complexes in the cavity. Through host-guest interaction, a supramolecular host-guest inclusion system is formed, and the viscosity peak will appear in the deep part of the reservoir, effectively blocking the high-permeability channel. Under the low-speed shear of reservoir seepage, in-situ viscosity enhancement can be achieved, realizing flow control and interfacial activity regulation.

[0061] (4) The present invention adopts a more efficient grafting synthesis method in the process of synthesizing thermosensitive grafted polymers. Unlike traditional free radical initiated polymerization, the synthesis experiment adopts a carboxyl activator and an activation enhancer to be added to the initiation system to form a highly active NHS ester intermediate, which improves the synthesis grafting rate and enables the grafting points to be accurately distributed on the polymer backbone. In addition, the DAAM is not damaged in a weakly acidic environment and the integrity of the thermosensitive functional groups is preserved, reducing the amount of polymer used and lowering the production cost.

[0062] (5) The supramolecular host-guest inclusion in-situ enhanced oil displacement system provided by the present invention has undergone pre-inclusion enhancement treatment before application. The weak interaction between solid nanoparticles and liquid polymer solution is established through low-intensity weak inclusion enhancement effect, thereby overcoming the separation phenomenon caused by component adsorption and molecular size differences during the migration of the oil displacement system in the reservoir, thus maintaining functional synergy, ensuring the timing accuracy of temperature-sensitive response, realizing deep and precise oil displacement, and improving the sweep efficiency of heterogeneous reservoirs. Attached Figure Description

[0063] Figure 1 This is a synthetic route diagram for silicon-based nanoparticles with cyclodextrin groups on their surface, as described in this invention.

[0064] Figure 2 This is a synthetic route diagram for the thermosensitive copolymer with terminal amino groups of the present invention.

[0065] Figure 3 This is a synthetic route diagram of the thermosensitive grafted polymer of the present invention.

[0066] Figure 4 This is the 1H NMR spectrum of the hydrophobic nano-silica in Example 1 of the present invention.

[0067] Figure 5 This is the 1H NMR spectrum of silicon-based nanoparticles with cyclodextrin groups on their surface, as shown in Example 1 of this invention.

[0068] Figure 6 This is the 1H NMR spectrum of the thermosensitive grafted polymer in Example 1 of the present invention.

[0069] Figure 7 The images show physical representations of the silicon-based nanoparticles with cyclodextrin groups on their surface, the temperature-sensitive grafted polymer, and the in-situ enhanced oil displacement system dispersed in deionized water according to the present invention. Detailed Implementation

[0070] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0071] Example 1

[0072] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system comprises the following components: 5.0 g of silicon-based nanoparticles with cyclodextrin groups on their surface, 10.0 g of thermosensitive grafted polymer, and 1.0 L of PBS buffer (0.01 mol / L, pH=7.4).

[0073] Preparation method of silicon-based nanoparticles with cyclodextrin groups on the surface (synthetic route as follows) Figure 1 (as shown)

[0074] (1) Preparation of hydrophobic nano-silica. 110.12 mg of γ-methacryloxypropyltrimethoxysilane was slowly added dropwise at a rate of 5 drops / second to 80 mL of an ethanol-water aqueous solution with a volume ratio of 9:1. The solution was stirred at room temperature for 40 min to hydrolyze the silane. The pH was adjusted to 5.0 using a 15% hydrochloric acid aqueous solution to obtain system 1. Then, 22.02 g of nano-silica powder with a particle size of 100 nm was slowly added to system 1. The solution was stirred with ultrasound throughout the process to obtain a stable suspension system 2. System 2 was heated to 70 °C and stirred under reflux for 6 h. After the reaction was completed, the heating was stopped and the solution was cooled to room temperature. The reaction solution of system 2 was centrifuged at 9000 rpm for 130 min to obtain the lower precipitate. The precipitate was ultrasonically washed three times with 50 mL of ethanol. Finally, the pure solid was placed in a vacuum drying oven and dried at 50 °C for 24 h until the particles were completely dry to obtain the modified hydrophobic nano-silica. The proton NMR spectrum is shown below. Figure 4 As shown, this demonstrates the successful preparation of the target product of the present invention.

[0075] (2) Preparation of silicon-based nanoparticles with cyclodextrin groups on the surface. 10.0 g of hydrophobic nano-silica was uniformly dispersed in 68.23 mL of deionized water. After sonication for 30 min, 5.0 g of allyl-β-cyclodextrin was added to obtain system 3. Then, nitrogen gas was purged into system 3 for 20 min to remove oxygen and maintain an inert atmosphere. Subsequently, system 3 was heated to 70 °C in a water bath and 0.10 g of ammonium persulfate was added. Under nitrogen protection, the mixture was stirred at a constant temperature for 8 h. After the reaction was completed, it was cooled to room temperature, and the reaction solution was centrifuged at 15000 rpm to obtain a precipitate. The precipitate was washed four times each with 50 mL of 50 °C deionized water, acetone, and ethanol to remove impurities. After drying under vacuum at 40 °C for 24 h, silicon-based nanoparticles with cyclodextrin groups on the surface were obtained. The proton NMR spectrum is shown below. Figure 5 As shown, this demonstrates the successful preparation of the target product of the present invention.

[0076] Preparation method of thermosensitive grafted polymer:

[0077] (1) Synthesis of the amino-terminated thermosensitive copolymer. 10.0 g of acrylamide and 2.5 g of diacetone acrylamide were dissolved in 50 mL of anhydrous methanol. Then, 0.4 g of 2-mercaptoethylamine hydrochloride and 40.0 mg of azobisisobutyronitrile were added sequentially to obtain liquid phase system 4. System 4 was subjected to repeated deoxygenation treatment three times, then sealed under nitrogen gas. The reaction was then stirred for 8 h in a constant temperature oil bath at 70 °C. After cooling to terminate the reaction, system 5 was obtained. The reaction solution of system 5 was added dropwise to a 1:1 mixture of diethyl ether and n-hexane. A white precipitate was formed by stirring. The white precipitate was washed three times with diethyl ether and then freeze-dried to obtain the amino-terminated thermosensitive copolymer. The synthetic route is as follows: Figure 2 As shown.

[0078] (2) Synthesis of thermosensitive graft polymer. 9.0 g of sodium polyacrylate (NaPAA, weight average molecular weight Mw=18100) was dissolved in 0.90 LMES buffer (100 mmol / L, pH 5.0, solvent: deionized water) and stirred until completely dissolved. 15 wt% dilute hydrochloric acid was added dropwise to adjust the pH of the solution to 5.0. The solution was cooled to 0-4℃ in an ice bath. Then, 3.35 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 2.09 g of N-hydroxysuccinimide were added. The mixture was stirred in an ice bath for 15 min and then moved to room temperature and stirred for another 45 min to obtain system 6. 4.50 g of the amino-terminated thermosensitive copolymer was dissolved in 300 mL of MES buffer (100 mmol / L, pH 5.0, deionized water) to obtain system 7. System 7 was then added dropwise to system 6 at a rate of 2 drops / second. The mixture was stirred at room temperature for 24 h under nitrogen protection. Then, 30 wt% NaOH aqueous solution was added to adjust the pH to 6.0. The final reaction solution was purified by dialyzing and then lyophilized to obtain the thermosensitive grafted polymer. The synthetic route is as follows: Figure 3 As shown. The proton NMR spectrum is as follows. Figure 6 As shown, this demonstrates the successful preparation of the target product of the present invention.

[0079] Preparation method of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system:

[0080] 5.0 g of silicon-based nanoparticles with cyclodextrin groups on their surface were dissolved in 0.50 L of PBS buffer and sonicated for 20 min to obtain dispersion system 8. 10.0 g of thermosensitive grafted polymer was dissolved in 0.50 L of PBS buffer at 4 °C to obtain solution system 9. Systems 8 and 9 were mixed and stirred at 4 °C for 2 h, then heated to 40 °C and stirred for another 1 h. The reaction solution was then purified by centrifugation at 12000 rpm to obtain a precipitate. The precipitate was washed four times with cold PBS (4 °C) buffer, purified, and then vacuum dried at 25 °C to obtain solid particles of the thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system. The actual oil displacement system obtained according to this example is shown below. Figure 7 As shown, from left to right, there are silicon-based nanoparticles with cyclodextrin groups on their surface, a temperature-sensitive grafted polymer, and an in-situ enhanced oil displacement system dispersed in deionized water.

[0081] The above-mentioned temperature-sensitive supramolecular host-guest inclusion in-situ enhanced oil recovery system is applied to chemical flooding in high-temperature reservoirs for enhanced oil recovery. The application method includes the following steps:

[0082] 10g of thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system solid particles were fully dispersed in 500mL of reservoir simulated mineralized water with a salinity of 1500mg / L. After stirring for 2h and the solution system was stabilized, the oil displacement chemical agent was obtained.

[0083] Example 2

[0084] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that the particle size of the nano-silica is 300 nm in the synthesis of silicon-based nanoparticles with cyclodextrin groups on the surface. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0085] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0086] Example 3

[0087] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that the amount of γ-methacryloyloxypropyltrimethoxysilane added is 165.18 mg in the synthesis of silicon-based nanoparticles with cyclodextrin groups on the surface. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0088] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0089] Example 4

[0090] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that the amount of allyl-β-cyclodextrin added is 2.5 g in the synthesis of silicon-based nanoparticles with cyclodextrin groups on the surface. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0091] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0092] Example 5

[0093] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that the amount of diacetone acrylamide added in the synthesis of the thermosensitive graft polymer is 1.6 g. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0094] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0095] Example 6

[0096] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that the amount of 2-mercaptoethylamine hydrochloride added in the synthesis of the thermosensitive graft polymer is 0.25 g. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0097] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0098] Example 7

[0099] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that the amount of sodium polyacrylate added in the synthesis of the thermosensitive graft polymer is 15.0 g. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0100] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0101] Example 8

[0102] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that in the synthesis of the thermosensitive graft polymer, the amount of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride added is 2.0 g, and the amount of N-hydroxysuccinimide added is 1.0 g. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0103] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0104] Example 9

[0105] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that the silane coupling agent in the synthesis of silicon-based nanoparticles with cyclodextrin groups on the surface is replaced with vinyltrimethoxysilane. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0106] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0107] Example 10

[0108] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that in the synthesis of silicon-based nanoparticles with cyclodextrin groups on the surface, the cyclodextrin-containing polymerizing monomer is replaced with 6-acryloylethylenediamine-β-cyclodextrin. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0109] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0110] Example 11

[0111] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that the initiator in the synthesis of silicon-based nanoparticles with cyclodextrin groups on the surface is replaced with cerium ammonium nitrate. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0112] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0113] Example 12

[0114] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that the chain transfer agent in the synthesis of the thermosensitive graft polymer is replaced with mercaptoacetic acid. The composition of other components, preparation steps, and conditions are the same as in Example 1.

[0115] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0116] Example 13

[0117] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that the carboxyl activator in the thermosensitive graft polymer synthesis is replaced with dicyclohexylcarbodiimide. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0118] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0119] Example 14

[0120] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is described in Example 1, except that the activator in the thermosensitive graft polymer synthesis is replaced with 1-hydroxybenzotriazole. The composition of other components, preparation steps, and conditions are the same as in Example 1.

[0121] The preparation and application methods of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system are the same as those in Example 1.

[0122] Example 15

[0123] A thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system, as described in Example 1, differs only in that the amount of thermosensitive grafted polymer used is 5.0 g. The preparation method of the above components is the same as in Example 1.

[0124] The preparation method of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is the same as described in Example 1, with the same differences. The application method is the same as in Example 1.

[0125] Example 16

[0126] A temperature-sensitive supramolecular host-guest encapsulation in-situ enhanced oil displacement system, with the same composition as in Example 1.

[0127] The preparation method of the above-mentioned thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is as described in Example 1, except that: system 8 and system 9 are mixed and stirred at 4°C for 2 hours, and then the temperature is raised to 60°C. Other steps and conditions are the same as in Example 1.

[0128] The application method of the above-mentioned thermosensitive supramolecular host-guest encapsulation in-situ enhanced oil displacement system is the same as in Example 1.

[0129] Comparative Example 1

[0130] An oil displacement system, as described in Example 1, differs only in that no activator is added during the synthesis of the temperature-sensitive graft polymer. The composition of other components, preparation steps, and conditions are the same as in Example 1.

[0131] The preparation and application methods of the above-mentioned oil displacement system are the same as those in Example 1.

[0132] Comparative Example 2

[0133] An oil displacement system, as described in Example 1, differs only in that diacetone acrylamide is not added during the synthesis of the temperature-sensitive graft polymer. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0134] The preparation and application methods of the above-mentioned oil displacement system are the same as those in Example 1.

[0135] Comparative Example 3

[0136] An oil displacement system, as described in Example 1, differs only in that step (2) is omitted in the synthesis of the thermosensitive graft polymer, thus directly obtaining the terminal amino thermosensitive copolymer. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0137] The preparation method of the above-mentioned oil displacement system is the same as that described in Example 1, except that it is the same as above.

[0138] The application method of the above-mentioned oil displacement system is the same as that in Example 1.

[0139] Comparative Example 4

[0140] An oil displacement system, as described in Example 1, except that the solvent is replaced with deionized water instead of PBS buffer. The composition, preparation steps, and conditions of other components are the same as in Example 1.

[0141] The preparation method of the above-mentioned oil displacement system is the same as that described in Example 1, except that it is the same as above.

[0142] The application method of the above-mentioned oil displacement system is the same as that in Example 1.

[0143] Comparative Example 5

[0144] A method for applying an oil displacement system involves mixing 10.0 g of a temperature-sensitive grafted polymer and 5.0 g of silicon-based nanoparticles with cyclodextrin groups on their surface in 500 mL of simulated mineralized water with a salinity of 1500 mg / L, and then using the mixture directly. The preparation methods for the temperature-sensitive grafted polymer and the silicon-based nanoparticles with cyclodextrin groups on their surface are the same as in Example 1.

[0145] Experimental Example 1

[0146] Viscosity testing of the oil displacement system. This experiment was used to test the viscosity of the oil displacement systems prepared in the examples and comparative examples. The test method is as follows:

[0147] The oil displacement chemical agents obtained from the examples and comparative examples were used. 80 mL of the sample was tested using a six-speed rotational viscometer at 25°C and 80°C. Another 80 mL sample was subjected to high-speed stirring and shearing at 80°C and 1000 r / min using a magnetic stirrer for 30 min, followed by standing at 80°C for 1 h. The viscosity after shearing was then tested using a rotational viscometer at 80°C. The experimental results are shown in Table 1.

[0148] Table 1 Viscosity data for different oil displacement systems

[0149]

[0150] As can be seen from the data in the table above, the oil displacement system of the present invention has low viscosity at 25°C, making it easy to inject into the formation. The viscosity increases at high temperatures, achieving plugging and oil displacement. It has temperature-sensitive response performance and high shear recovery performance in high-temperature environments.

[0151] Experimental Example 2

[0152] Oil displacement efficiency test of the oil displacement system. This experiment was used to test the efficiency of the oil displacement systems prepared in the examples and comparative examples in simulated core oil displacement. The test method is as follows:

[0153] The oil displacement chemical agent obtained from the examples and comparative examples was applied to a core model (size Φ2.5 cm × 2.5 cm × 10 cm, porosity 13.45%, permeability 10 × 10⁻⁶). -3 μm 2 Saturated crude oil (20 mP·s) was placed in a core holder for displacement experiments. The equipment temperature was maintained at 80℃, and formation water was injected at a flow rate of 1 mL / min for pre-water flooding. After the core holder stopped producing oil and water continuously for 5 minutes, the injection of formation water was stopped. Then, an oil displacement chemical was injected at a flow rate of 0.5 mL / min. After the fluid flow stabilized, the injection was stopped and the mixture was allowed to stand for 5 hours. Subsequent water flooding was then carried out, and the changes in permeability and the amount of oil produced after displacement were measured to obtain the plugging rate and improved oil recovery rate. The experimental results are shown in Table 2.

[0154] Table 2. Enhanced Oil Recovery Data for Different Oil Displacement Systems

[0155]

[0156] As shown in the table above, the oil displacement system of this invention achieves a plugging rate of over 90% and an oil displacement efficiency of over 20%, effectively realizing plugging and oil displacement, thereby improving the recovery rate.

[0157] The above description is merely a preferred embodiment of the present invention and is 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 make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A temperature-sensitive supramolecular host-guest encapsulation in-situ enhanced oil displacement system, characterized in that, It comprises the following components: silicon-based nanoparticles with cyclodextrin groups on their surface and a temperature-sensitive grafted polymer; the mass ratio of silicon-based nanoparticles with cyclodextrin groups on their surface and the temperature-sensitive grafted polymer is 1:1-2. A method for preparing silicon-based nanoparticles with cyclodextrin groups on their surface, comprising the following steps: A1: The silane coupling agent is added dropwise to an ethanol-water solution, followed by a hydrolysis reaction, and then the pH is adjusted to 5.

0. Nano-silica is added, fully dispersed, reacted, centrifuged, washed, and dried to obtain hydrophobic nano-silica. The mass ratio of nano-silica to silane coupling agent is 200:

1. The silane coupling agent is one of vinyltrimethoxysilane or γ-methacryloyloxypropyltrimethoxysilane. A2: Hydrophobic nano-silica is fully dispersed in deionized water, and cyclodextrin-containing polymerizing monomer and initiator 1 are added. After reaction, centrifugation, washing and drying are performed to obtain silicon-based nanoparticles with cyclodextrin groups on the surface; the cyclodextrin-containing polymerizing monomer is allyl-β-cyclodextrin. The preparation method of the thermosensitive grafted polymer includes the following steps: B1: Acrylamide and diacetone acrylamide are dissolved in anhydrous methanol, chain transfer agent and initiator 2 are added, and the mixture is reacted. Then, the product is purified, washed, and dried to obtain an amino-terminated thermosensitive copolymer. The mass ratio of acrylamide, diacetone acrylamide, chain transfer agent, and initiator 2 is 250: 62.5: 6.25-10:

1. The chain transfer agent is 2-mercaptoethylamine hydrochloride. B2: Dissolve sodium polyacrylate in 2-morpholinoethanesulfonic acid buffer, adjust the pH to 5.0, add a carboxyl activator and an activation enhancer, and proceed with the reaction; add a mixture of terminal amino thermosensitive copolymer and 2-morpholinoethanesulfonic acid buffer dropwise, proceed with the reaction, then adjust the pH to 6.0, dialysis for purification, and lyophilize to obtain the thermosensitive graft polymer; the carboxyl activator is one of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, dicyclohexylcarbodiimide, or diisopropylcarbodiimide; the activation enhancer is one of N-hydroxysuccinimide or 1-hydroxybenzotriazole; The preparation method of the thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system is characterized by comprising the following steps: Silicon-based nanoparticles with cyclodextrin groups on their surface were dissolved in PBS buffer to obtain mixture 1; thermosensitive grafted polymers were dissolved in PBS buffer at 1-5℃ with stirring to obtain mixture 2; mixture 1 and mixture 2 were mixed and stirred at 1-5℃ for 1-3 hours, the temperature was raised to above the minimum critical co-solution temperature, stirring was continued for 0.5-2 hours, centrifuged, washed with PBS buffer at 1-5℃, and vacuum dried to obtain a thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system; the minimum critical co-solution temperature was above 40℃.

2. The thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system according to claim 1, characterized in that, Step A1 includes one or more of the following conditions: i. In an aqueous ethanol solution, the volume ratio of ethanol to water is 5-10:1; ii. The mass ratio of the silane coupling agent to the volume ratio of the ethanol aqueous solution is 1-3 mg / mL; iii. The hydrolysis reaction temperature is room temperature, the hydrolysis reaction time is 20-60 min, and the hydrolysis reaction is carried out under stirring conditions; iv. Adjust the pH of the reaction system using a 10-20% hydrochloric acid aqueous solution; v. The particle size of nano-silica is 50-500nm; vi. The reaction temperature after adding nano-silica is 60-80℃, the reaction time is 4-8h, and the reaction is carried out under reflux and stirring conditions.

3. The thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system according to claim 1, characterized in that, Step A2 includes one or more of the following conditions: i. The mass ratio of hydrophobic nano-silica to the volume ratio of deionized water is 0.1-0.5 g / mL; ii. Initiator 1 is one of ammonium persulfate, potassium persulfate, or cerium ammonium nitrate; iii. The mass ratio of hydrophobic nano-silica, cyclodextrin-containing polymerizing monomer, and initiator 1 is 100-400:20-220:1; iv. The reaction temperature is 60-80℃, the reaction time is 6-10h, and the reaction is carried out under anaerobic, protective gas, and stirring conditions; the protective gas is nitrogen or argon.

4. The thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system according to claim 1, characterized in that, Step B1 includes one or more of the following conditions: i. Initiator 2 is one of azobisisobutyronitrile, dimethyl azobisisobutyrate or azobisisoheptanenitrile; ii. The mass ratio of acrylamide to anhydrous methanol is 1:1-10 g / mL; iii. The reaction temperature is 60-80℃, the reaction time is 6-10h, and the reaction is carried out under oxygen-free, protective gas, and stirring conditions.

5. The thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system according to claim 1, characterized in that, Step B2 includes one or more of the following conditions: i. The mass ratio of sodium polyacrylate to the volume ratio of 2-morpholinoethanesulfonic acid buffer is 0.1-10:100 g / mL; ii. Adjust the pH to 5.0 by adding a 10-20% hydrochloric acid aqueous solution; iii. The mass ratio of sodium polyacrylate, carboxyl activator, and activating enhancer is 3-10:1-4:1; iv. The reaction conditions after adding the carboxyl activator and the activation enhancer are as follows: stir at 0-4℃ for 10-20 min, and then stir at room temperature for 40-50 min; v. In the mixture of amino-terminated thermosensitive copolymer and 2-morpholinoethanesulfonic acid buffer, the mass ratio of amino-terminated thermosensitive copolymer to volume ratio of 2-morpholinoethanesulfonic acid buffer is 1-5:200 g / mL. vi, the mass ratio of sodium polyacrylate and amino-terminated thermosensitive copolymer is 2-4:1; vii. The reaction temperature after adding the mixture of terminal amino thermosensitive copolymer and 2-morpholinoethanesulfonic acid buffer was room temperature, and the reaction time was 20-30 h. The reaction was carried out under protective gas and stirring conditions; the protective gas was nitrogen or argon. viii. Adjust the pH to 6.0 using a 15-30% NaOH aqueous solution; ix, 2-morpholinoethanesulfonic acid buffer is an aqueous solution of 2-morpholinoethanesulfonic acid with a concentration of 100 mmol / L and a pH of 5.

0.

6. The thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system according to claim 1, characterized in that, The thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system also includes PBS buffer, with a concentration of 0.01 mol / L and pH=7.4; the total mass ratio of silicon-based nanoparticles with cyclodextrin groups on the surface and thermosensitive grafted polymer to the volume of PBS buffer is 10-15 g / L.

7. The thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system according to claim 1, characterized in that, The volume ratio of PBS buffer in mixture 1 to PBS buffer in mixture 2 is 0.5-4:

1.

8. The application of the thermosensitive supramolecular host-guest inclusion in-situ enhanced oil displacement system as described in any one of claims 1-7 in oil displacement.

Images