A carbon nanotube-enhanced polymer displacement agent and its preparation method and application

Abstract

The present invention provides a carbon nanotube-enhanced polymer displacement agent, its preparation method, and application. The carbon nanotube-enhanced polymer displacement agent is obtained by in-situ generation of polyacrylamide on an interpenetrating network structure composed of polyethylene glycol and carbon nanotubes without adding a small molecule crosslinking agent. The carbon nanotube-enhanced polymer displacement agent can withstand high temperatures of 110°C and above, 20×10 4 The high mineralization of 1000 mg / L and the self-healing function of cut-off self-healing can achieve long-term, stable and effective regulation of reservoir flow channels, improve the liquid absorption profile of the reservoir, increase the water flooding sweep volume, and control water and increase oil production.

Description

Technical Field

[0001] The present invention belongs to the technical field of flow channel regulation in oil reservoirs, and in particular relates to a carbon nanotube-enhanced polymer flow control agent, a preparation method thereof, and an application thereof. Background Art

[0002] Water-driven oil reservoirs account for over 80% of my country's oilfields. Long-term erosion of injected water creates dominant flow paths, resulting in low water-sweep efficiency. Under extreme water-cut conditions in oil wells, oil recovery is only around 30%, leaving a significant amount of crude oil unrecovered. Controlling the dominant flow paths and expanding the swept volume of injected water are key and effective strategies for controlling water and increasing oil production in water-driven reservoirs.

[0003] Currently, the primary methods for controlling the flow path in water injection wells include injecting foams, weak gels, gel dispersions, colloidal dispersions, pre-crosslinked particles, polymer microspheres, and polymer dispersions. Foams have excellent fluidity control capabilities, increasing injection pressure and improving the liquid absorption profile. However, the foam generation process in the formation is prone to gas channeling, limiting their ability to control the flow path. Gel dispersions, weak gels, and colloidal dispersions are formed by the reaction of polymers or monomers with crosslinkers in the formation, which are prone to filtration and matrix contamination. Pre-crosslinked particles have the property of swelling upon absorbing water, providing a good plugging effect on large pores in high-water-content, high-recovery oil fields. However, the preparation process for pre-crosslinked particles is complex, costly, and easily lost from oil wells, which affects their flow path control effectiveness. Polymer dispersions are hydrogels prepared using surface technologies and techniques and have great potential for application. They are generally obtained by reacting hydrogels with crosslinkers through methods such as dispersion polymerization, inverse suspension polymerization, inverse emulsion polymerization, and inverse microemulsion polymerization. When the ambient temperature rises, the movement rate of hydrogel molecules and cross-linker molecules accelerates, the probability of intermolecular collision increases, the reaction activation energy increases, and the possibility of reaction between hydrogel and cross-linker increases, so the water absorption and expansion rate of the hydrogel will increase; when the temperature of the reaction solution continues to rise, the gelation time of the hydrogel becomes shorter and the gelation strength increases; but if the temperature is too high, the hydrogel molecules degrade, and gel dehydration and gel breakage will occur, and the stability is poor. Summary of the Invention

[0004] To address the problem that existing polymer dispersions have poor salt and temperature resistance and cannot maintain long-term stability in high-temperature, high-salt environments, the present invention aims to provide a carbon nanotube-reinforced polymer flooding agent, its preparation method, and its application. The carbon nanotube-reinforced polymer flooding agent provided by the present invention exhibits self-healing properties, capable of undergoing a reversible break-and-replenish reaction, allowing it to automatically repair itself to its original state when damaged. It can maintain long-term stability in high-temperature, high-salt environments, effectively controlling the dominant flow path.

[0005] One of the present inventions provides a carbon nanotube-enhanced polymer displacement agent, which includes polyethylene glycol, carbon nanotubes and polyacrylamide;

[0006] The polyethylene glycol and the carbon nanotubes form an interpenetrating network structure; the polyacrylamide is obtained by in-situ reaction of acrylamide and an initiator on the interpenetrating network structure.

[0007] According to a specific embodiment of the present invention, the mass of the carbon nanotube-enhanced polymer displacement agent is calculated as 100%, and the carbon nanotube-enhanced polymer displacement agent includes 25.8wt% to 28.2wt% of polyethylene glycol, 0.65wt% to 0.9wt% of carbon nanotubes and 71.1wt% to 73.5wt% of polyacrylamide.

[0008] According to a specific embodiment of the present invention, the weight average molecular weight of the polyethylene glycol is 5,000 to 10,000.

[0009] According to a specific embodiment of the present invention, the carbon nanotubes are single-walled carbon nanotubes and / or multi-walled carbon nanotubes;

[0010] Preferably, the outer diameter of the single-walled carbon nanotube is 3 nm to 20 nm and the length is 0.1 μm to 10 μm; and / or

[0011] The multi-walled carbon nanotubes have an outer diameter of 20 nm to 200 nm and a length of 1.0 μm to 30 μm.

[0012] According to a specific embodiment of the present invention, the initiator is at least one of azobisisobutyronitrile, azobisisoheptanenitrile and azobisisobutyramidine hydrochloride.

[0013] The second aspect of the present invention provides a method for preparing the carbon nanotube-enhanced polymer displacement agent according to the first aspect of the present invention, which comprises the following steps:

[0014] 1) mixing the polyethylene glycol, carbon nanotubes and a solvent to obtain an interpenetrating network solution;

[0015] 2) mixing the acrylamide, initiator and interpenetrating network solution, reacting them, and in-situ generating polyacrylamide on the interpenetrating network structure to obtain the carbon nanotube-enhanced polymer displacement agent.

[0016] According to a specific embodiment of the present invention, in step 1), the polyethylene glycol and the heated solvent are first mixed, and then mixed with the carbon nanotubes to obtain the interpenetrating network solution;

[0017] and / or

[0018] In step 2), the reaction product obtained by the reaction is dried to obtain the carbon nanotube-enhanced polymer displacement agent;

[0019] Preferably, the reaction product is dried and then crushed to obtain the carbon nanotube-enhanced polymer displacement agent with a particle size of 5 μm to 50 μm.

[0020] According to a specific embodiment of the present invention, the total mass of the polyethylene glycol, carbon nanotubes, acrylamide and initiator is 100%, the amount of the polyethylene glycol is 25.8wt% to 28.2wt%, the amount of the carbon nanotubes is 0.65wt% to 0.9wt%, the amount of the acrylamide is 70.4wt% to 72.5wt%, and the amount of the initiator is 0.7wt% to 1wt%; and / or

[0021] The total weight of the polyethylene glycol, carbon nanotubes, acrylamide, initiator and solvent is 100%, and the amount of the solvent is 72 wt % to 77.9 wt %;

[0022] Preferably, the solvent is water.

[0023] According to one embodiment of the present invention, the temperature of the heated solvent and the temperature of the reaction are independently 78° C. to 83° C.; and / or

[0024] The drying temperature is 90°C to 110°C; and / or

[0025] The reaction time is 5 to 7 hours;

[0026] Preferably, the reaction is carried out in an oxygen-free, sealed environment;

[0027] Preferably, the temperature of the solvent after being heated is 80°C; and / or

[0028] The temperature of the reaction is 80°C to 83°C.

[0029] Application of the carbon nanotube-enhanced polymer flooding agent according to one embodiment of the present invention or the carbon nanotube-enhanced polymer flooding agent prepared by the method according to the second embodiment of the present invention in flow channel regulation technology for oil reservoirs, particularly in flow channel regulation technology for high-temperature and high-salinity oil reservoirs;

[0030] Preferably, the high temperature is not less than 110°C; and / or the high mineralization is not less than 200,000 mg / L. Beneficial effects of the present invention:

[0031] In view of the problem that the polymer dispersion glue in the prior art has poor salt and temperature resistance and cannot remain stable in a high temperature and high salt environment for a long time, the present invention provides a carbon nanotube-enhanced polymer displacement agent and its preparation method and application. The carbon nanotube-enhanced polymer displacement agent is obtained by reacting acrylamide and an initiator without adding a small molecule cross-linking agent, and in situ generating polyacrylamide on an interpenetrating network structure composed of polyethylene glycol and carbon nanotubes. The carbon nanotube-enhanced polymer displacement agent can undergo a reversible self-repairing process of breaking and replenishing, has good stability under high temperature and high salt conditions, has a temperature resistance of not less than 110°C, and a salt resistance of not less than 200,000 mg / L. Specifically, the carbon nanotube-enhanced polymer displacement agent and the mineralization degree are 5.0×10 4 mg / L to 21.0×10 4 After aging for 30 days at 120°C, the hydrogel prepared from brine with a concentration of 100 mg / L had a flow diversion pressure of 850 kPa. The carbon nanotube-enhanced polymer flooding agent and the salinity of the hydrogel were 25.0×10 4 mg / L of saline solution, the hydrogel had a flow diversion pressure of 820 kPa after aging at 120 °C for 30 days. The carbon nanotube-enhanced polymer flooding agent and the salinity were 21.0×10 4 A hydrogel containing 0.2 wt% of a carbon nanotube-enhanced polymer flooding agent, prepared in brine containing 0.1 mg / L of water, was aged at 120°C for 10 days. Then, a 0.2 PV injection at 120°C increased crude oil recovery by 20.2%. This demonstrates that the carbon nanotube-enhanced polymer flooding agent provided by the present invention exhibits strong rigidity under high-temperature and high-salinity conditions. Even at a low concentration of 0.2 wt%, it can effectively regulate reservoir heterogeneity, finely adjust water flooding flow channels, increase the swept volume of water-flooded reservoirs, and enhance water flooding recovery, achieving significant water control and oil production enhancement. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 shows a scanning electron microscope image of the carbon nanotube-enhanced polymer displacement agent prepared in Example 2;

[0033] Figure 2 The self-healing process of the hydrogel prepared by the carbon nanotube-enhanced polymer displacement agent prepared in Example 3 is shown;

[0034] Figure 3 The figure shows the regulation of water flooding by the carbon nanotube-enhanced polymer flooding agent prepared in Example 3. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to examples. However, the examples are merely illustrative and do not limit the present invention in any way.

[0036] Carbon nanotubes used in Examples 1 to 4:

[0037] Single-walled carbon nanotubes, industrial grade, with specifications of: outer diameter 3 to 20 nm, length 0.1 to 10 μm.

[0038] Multi-walled carbon nanotubes, industrial grade, with specifications of: outer diameter 20 to 200 nm, length 1.0 to 30 μm.

[0039] Example 1

[0040] 1) Heat 100 mL of distilled water to 80°C, add 8 g of polyethylene glycol (weight-average molecular weight 5000), stir until completely dissolved, then add 0.2 g of single-walled carbon nanotubes (SWCNTs) while stirring, and mix thoroughly to obtain an interpenetrating network solution.

[0041] 2) Adding 20 g of acrylamide and 0.2 g of azobisisobutyronitrile to the obtained interpenetrating network solution, deoxygenating the mixture with nitrogen for 15 min, sealing the mixture, heating the mixture to 80° C., and reacting the mixture for 5 h. The obtained reaction product was dried at 100° C. and crushed to obtain a single-walled carbon nanotube-reinforced polymer displacement agent with a particle size of 5 to 50 μm.

[0042] Example 2

[0043] 1) Heat 100 mL of distilled water to 80°C, add 9 g of polyethylene glycol (weight-average molecular weight 7500), and stir until completely dissolved. Then, add 0.3 g of multi-walled carbon nanotubes while stirring, and mix thoroughly to obtain an interpenetrating network solution.

[0044] 2) Add 25 g of acrylamide and 0.3 g of azobisisoheptanonitrile to the obtained interpenetrating network solution, deoxygenate with nitrogen for 15 minutes, seal the mixture, heat to 82° C., react for 6.5 hours, and dry the obtained reaction product at 90° C. and crush to obtain a multi-walled carbon nanotube-reinforced polymer displacement agent with a particle size of 5 to 50 μm.

[0045] Example 3

[0046] 1) Heat 100 mL of distilled water to 80°C, add 10 g of polyethylene glycol (weight-average molecular weight 10,000), and stir until completely dissolved. Then, add 0.3 g of multi-walled carbon nanotubes while stirring and mix thoroughly to obtain an interpenetrating network solution.

[0047] 2) Adding 28 g of acrylamide and 0.4 g of azobisisobutylamidine hydrochloride to the obtained interpenetrating network solution, deoxygenating the mixture with nitrogen for 15 min, sealing the mixture, heating the mixture to 83° C., reacting the mixture for 7 h, and drying the obtained reaction product at 110° C. and pulverizing the mixture to obtain a multi-walled carbon nanotube-reinforced polymer displacement agent with a particle size of 5 to 50 μm.

[0048] Example 4

[0049] 1) Heat 100 mL of distilled water to 80°C, add 10 g of polyethylene glycol (weight-average molecular weight 10,000), and stir until completely dissolved. Then, add 0.10 g of single-walled carbon nanotubes and 0.15 g of multi-walled carbon nanotubes while stirring, and mix thoroughly to obtain an interpenetrating network solution.

[0050] 2) Adding 28 g of acrylamide and 0.4 g of azobisisobutylamidine hydrochloride to the obtained interpenetrating network solution, deoxygenating the mixture with nitrogen for 15 min, sealing the mixture, heating the mixture to 83° C., reacting the mixture for 7 h, and drying the obtained reaction product at 110° C. and pulverizing the mixture to obtain a multi-walled carbon nanotube-reinforced polymer displacement agent with a particle size of 5 to 50 μm.

[0051] Experimental evaluation

[0052] 1. Characterization of the micromorphology of carbon nanotube-enhanced polymer displacement agents

[0053] The microstructures of the carbon nanotube-enhanced polymer displacement agents prepared in Examples 1 to 4 were observed using a scanning electron microscope. Here, the carbon nanotube-enhanced polymer displacement agent prepared in Example 2 is used as an example for detailed description.

[0054] Figure 1 This is a scanning electron microscope image of the carbon nanotube-reinforced polymer displacement agent prepared in Example 2. Overall, the surface of the carbon nanotube-reinforced polymer displacement agent exhibits a dense network structure; the carbon nanotubes are dispersed within the gel network, forming an interpenetrating network. This demonstrates that the polyethylene glycol and carbon nanotubes form a dynamically cross-linked interpenetrating network structure.

[0055] The carbon nanotube-enhanced polymer displacement agent prepared in Examples 1, 3, and 4 can be observed under a scanning electron microscope. Figure 1 The microscopic morphology is similar to that of the carbon nanotube-reinforced polymer displacement agent prepared in Example 2: the surface presents a dense network structure; the carbon nanotubes are dispersed in the network space of the gel to form an interpenetrating network structure, that is, the polyethylene glycol and the carbon nanotubes form a dynamically cross-linked interpenetrating network structure.

[0056] 2. Performance evaluation of carbon nanotube-enhanced polymer displacement agents

[0057] The following experiments used brines with different mineralizations: Sodium chloride, water-soluble calcium salts, and water-soluble magnesium salts were dissolved in deionized water to prepare the following five brines with different mineralizations:

[0058] 1# brine: total mineralization is 5.0×10 4 mg / L, of which Ca 2+ and Mg 2+ The total concentration is 0.1×10 4 mg / L;

[0059] 2# brine: total mineralization is 10.0×10 4 mg / L, of which Ca 2+ and Mg 2+ The total concentration is 0.3×10 4 mg / L;

[0060] 3# brine: total mineralization is 15.0×10 4 mg / L, of which Ca 2+ and Mg 2+ The total concentration is 0.5×10 4 mg / L;

[0061] 4# brine: total mineralization is 21.0×10 4 mg / L, of which Ca 2+ and Mg 2+ The total concentration is 2×10 4 mg / L;

[0062] 5# brine: total mineralization is 25.0×10 4 mg / L, of which Ca 2+ and Mg 2+ The total concentration is 2.5×10 4 mg / L.

[0063] A. Evaluation of the Flow Diversion Performance of Carbon Nanotube-Reinforced Polymer Displacement Agents

[0064] The flow diversion performance of the carbon nanotube-enhanced polymer displacement agent was evaluated by measuring the diversion pressure of the carbon nanotube-enhanced polymer displacement agent prepared in Examples 1 to 4.

[0065] (1) 120℃, 5.0×10 4 mg / L to 21.0×10 4 Determination of flow diversion performance of carbon nanotube-enhanced polymer displacement agent under mg / L conditions

[0066] a. Preparation of hydrogel

[0067] Four equal portions of carbon nanotube-enhanced polymer displacement agent were placed in 1#, 2#, 3#, and 4# brine, respectively, to obtain four hydrogels with a carbon nanotube-enhanced polymer displacement agent mass fraction of 0.2 wt%. The hydrogels were aged at 120°C for 30 days before use.

[0068] b. Steering pressure measurement

[0069] At an injection rate of 0.3 mL / min, four aged hydrogels were passed through three layers of 80-mesh sieves to simulate porous formation media and shearing. Since the carbon nanotube-enhanced polymer displacement agent expands after being placed in brine, the resulting hydrogels are larger than the diameter of the three overlapping layers of 80-mesh sieves, causing them to accumulate on the sieves. The hydrogels can only pass through the sieves when the displacement pressure reaches a certain value, which is called the deflection pressure.

[0070] According to the above steps a and b, the turning pressures of the carbon nanotube-enhanced polymer displacement agents prepared in Examples 1 to 4 were measured respectively. The specific data are shown in Table 1.

[0071] Table 1. Steering pressure of carbon nanotube-enhanced polymer displacement agents prepared in Examples 1 to 4

[0072]

[0073] Table 1 shows that the carbon nanotube-enhanced polymer displacement agent prepared in Examples 1 to 4 has a mineralization of 5.0×10 4 mg / L to 21.0×10 4 After aging for 30 days at 120°C, the hydrogels prepared with 100 mg / L brine exhibited a diversion pressure of 760 to 853 kPa. This demonstrates that the carbon nanotube-reinforced polymer flooding agents prepared in Examples 1 to 4 exhibit excellent salt tolerance and strong rigidity, effectively regulating reservoir flow paths, improving the reservoir's liquid absorption profile, and increasing the swept volume of water flooding, thereby achieving water control and oil production increase.

[0074] (2) 120℃, 21.0×10 4 mg / L to 25.0×10 4 Determination of flow diversion performance of carbon nanotube-enhanced polymer displacement agent under mg / L conditions

[0075] i. Preparation of hydrogels: Weigh two equal parts by weight of the carbon nanotube-enhanced polymer displacement agents prepared in Examples 3 and 4, respectively, and place them in 4# and 5# saline solutions, respectively, to obtain four hydrogels each containing 0.2 wt% of the carbon nanotube-enhanced polymer displacement agent. The hydrogels were aged at 120°C for 30 days before use.

[0076] ii. At an injection rate of 0.3 mL / min, the four aged hydrogels were respectively passed through three layers of 80-mesh sieves to simulate the porous medium and shear process of the formation. The steering pressures of the carbon nanotube-enhanced polymer displacement agents prepared in Examples 3 and 4 were obtained as shown in Table 2.

[0077] Table 2. Steering pressure of carbon nanotube-enhanced polymer displacement agents prepared in Examples 3 and 4

[0078]

[0079] The data in Table 2 show that the carbon nanotube-enhanced polymer displacement agent prepared in Examples 3 and 4 has a mineralization of 21.0×10 4 mg / L to 25.0×10 4 After aging for 30 days at 120°C, the hydrogel prepared from brine containing 100 mg / L of water still had a steering pressure of 736 to 832 kPa. This proves that the carbon nanotube-reinforced polymer flooding agent provided by the present invention still has strong rigidity under high temperature and ultra-high salinity, can effectively regulate oil reservoir flow channels, improve the liquid absorption profile of the reservoir, significantly increase the water flooding swept volume, and control water and increase oil production.

[0080] B. Evaluation of the Self-Repair Performance of Carbon Nanotube-Reinforced Polymer Displacement Agent Cut-off and Self-Healing

[0081] The shear-self-healing performance of the carbon nanotube-enhanced polymer displacement agent prepared in Example 3 was evaluated according to the following method:

[0082] 1) Preparation of hydrogel: The carbon nanotube-enhanced polymer displacement agent prepared in Example 3 was placed in 4# salt water to obtain a hydrogel containing 0.2 wt% of the carbon nanotube-enhanced polymer displacement agent, and the hydrogel was aged at 120° C. for 30 days before use;

[0083] 2) The prepared hydrogel was cut into two halves, the cut surfaces of the two halves of the hydrogel were connected together, a slight stress was applied to the connected parts to make them in close contact, and then they were immersed in a 4# saline solution. After standing for 20 minutes, the final self-healing condition was observed.

[0084] Figure 2 This figure shows the self-healing behavior of a hydrogel prepared using the carbon nanotube-reinforced polymer displacement agent prepared in Example 3. Following the sequence of (a), (b), (c), and (d), it can be seen that the two halves of the hydrogel, reconnected at the cut surface after immersion in saline, undergo a self-healing process. Folding the halves in half at the cut surface or pulling in opposite directions cannot separate the two halves, demonstrating the excellent self-healing properties of the hydrogel.

[0085] Verified by the same method, after the hydrogel further prepared using the carbon nanotube-reinforced polymer drive agent prepared in Example 1, 2 or 4 was cut, the two halves of the hydrogel reconnected at the cut surface underwent a self-healing process after being soaked in salt water. Folding the cross section or pulling in two opposite directions could not separate the two halves of the hydrogel again, and the hydrogel also had excellent self-healing properties.

[0086] C. Determination of the injectability and water control and oil-increasing performance of carbon nanotube-enhanced polymer displacement agents

[0087] The following simulation experiment was conducted using the carbon nanotube-enhanced polymer displacement agent prepared in Example 3 to evaluate the injectability and water control and oil increase performance of the carbon nanotube-enhanced polymer displacement agent prepared in Example 3.

[0088] Artificial three-layer heterogeneous core: Gas permeability is 1000 / 3000 / 5000mD, average porosity is 26.7%, and initial oil saturation is 26.7%;

[0089] Crude oil: viscosity 20.3 mPa·s;

[0090] Aged hydrogel: The carbon nanotube-enhanced polymer displacement agent prepared in Example 3 was dried and crushed into particles of 5 to 20 μm, and then placed in 4# salt water to obtain a hydrogel with a mass fraction of 0.2 wt% carbon nanotube-enhanced polymer displacement agent. The hydrogel was aged at 120°C in a sealed state for 10 days before use.

[0091] Follow the steps below to conduct a simulation experiment at 120°C, with a fixed injection rate of 0.5 mL / min throughout the process:

[0092] (1) Perform a water flooding operation on the artificial three-layer heterogeneous core until no oil is produced. Record the changes of injection pressure, water content, and cumulative recovery rate with injected pore volume during the water flooding process.

[0093] (2) Then, 0.2PV of hydrogel was injected into the artificial three-layer heterogeneous core after the first water flooding for polymer flooding, and finally a second water flooding was performed. The changes in injection pressure, water content, and cumulative recovery rate with the injected pore volume during the polymer flooding and second water flooding processes were recorded.

[0094] For details, see Figure 3 .

[0095] Figure 3 This shows the simulation experiment of further preparing the carbon nanotube-enhanced polymer displacement agent prepared in Example 3 into a hydrogel. Figure 3It can be seen that due to the strong heterogeneity of the core, the recovery rate of the first water flooding is low, only 35%; after injecting 0.2PV of hydrogel, the injection pressure increases, indicating that the carbon nanotube-enhanced polymer displacement agent prepared in Example 3 has good injectability and propagation properties; the injection pressure in the secondary water flooding stage further increases, proving that the hydrogel further prepared from the carbon nanotube-enhanced polymer displacement agent prepared in Example 3 has entered the high permeability layer during the polymer flooding process of the simulation experiment and exhibits excellent anti-scouring performance. After injecting 0.2PV of hydrogel further prepared from the carbon nanotube-enhanced polymer displacement agent prepared in Example 3, the crude oil recovery rate increased by 20.2%. The above experimental results show that the carbon nanotube-enhanced polymer displacement agent prepared in Example 3 has good performance at low concentration (specifically 0.2wt%) and high mineralization (specifically 21.0×10 4 mg / L) and high temperature (specifically 120°C), the water drive flow channel can be well adjusted, and the effect of controlling water and increasing oil production is significant.

[0096] Although the present invention has been described with reference to specific embodiments, those skilled in the art will appreciate that various modifications may be made without departing from the true spirit and scope of the invention. Furthermore, the subject matter, spirit, and scope of the invention may be modified in various ways to adapt to specific circumstances, materials, combinations of materials, and methods. All such modifications are intended to be within the scope of the claims.

Claims

1. A carbon nanotube-enhanced polymer displacement agent comprising polyethylene glycol, carbon nanotubes, and polyacrylamide; The polyethylene glycol and carbon nanotubes form an interpenetrating network structure; The specific steps of forming the interpenetrating network structure are: firstly mixing the polyethylene glycol with a heated solvent, and then mixing with the carbon nanotubes to obtain an interpenetrating network solution; The polyacrylamide is obtained by in-situ reaction of acrylamide and an initiator on the interpenetrating network structure; The mass of the carbon nanotube-enhanced polymer driving agent is calculated as 100%, and the carbon nanotube-enhanced polymer driving agent comprises 25.8 wt % to 28.2 wt % of polyethylene glycol, 0.65 wt % to 0.9 wt % of carbon nanotubes, and 71.1 wt % to 73.5 wt % of polyacrylamide; The total weight of the polyethylene glycol, carbon nanotubes, acrylamide, initiator and solvent is calculated as 100%, and the amount of the solvent is 72 wt % to 77.9 wt %; The weight average molecular weight of the polyethylene glycol is 5000 to 10000; The solvent is water; The temperature of the solvent after being heated is 78°C to 83°C.

2. The carbon nanotube-enhanced polymer displacement agent according to claim 1, characterized in that: The carbon nanotubes are single-walled carbon nanotubes and / or multi-walled carbon nanotubes.

3. The carbon nanotube-enhanced polymer displacement agent according to claim 1 or 2, characterized in that: The initiator is at least one of azobisisobutyronitrile, azobisisoheptanenitrile and azobisisobutyramidine hydrochloride.

4. A method for preparing the carbon nanotube-enhanced polymer displacement agent according to any one of claims 1 to 3, comprising the following steps: 1) mixing the polyethylene glycol, carbon nanotubes and a solvent to obtain an interpenetrating network solution; 2) mixing the acrylamide, initiator and interpenetrating network solution, reacting them, and in-situ generating polyacrylamide on the interpenetrating network structure to obtain the carbon nanotube-enhanced polymer displacement agent.

5. The method according to claim 4, characterized in that In step 2), the reaction product obtained by the reaction is dried to obtain the carbon nanotube-enhanced polymer displacement agent.

6. The method according to claim 4, characterized in that Taking the total weight of the polyethylene glycol, carbon nanotubes, acrylamide and initiator as 100%, the amount of the polyethylene glycol is 25.8 wt % to 28.2 wt %, the amount of the carbon nanotubes is 0.65 wt % to 0.9 wt %, the amount of the acrylamide is 70.4 wt % to 72.5 wt %, and the amount of the initiator is 0.7 wt % to 1 wt %.

7. The method according to any one of claims 4 to 6, characterized in that The reaction temperature is 78°C to 83°C; and / or The reaction time is 5 to 7 hours; The reaction is carried out in an oxygen-free, sealed environment.

8. The method according to claim 5, characterized in that The drying temperature is 90°C to 110°C.

9. Use of the carbon nanotube-enhanced polymer flooding agent according to any one of claims 1 to 3 or the carbon nanotube-enhanced polymer flooding agent prepared by the method according to any one of claims 4 to 8 in oil reservoir flow channel control technology.

10. The use according to claim 9, characterized in that The application is the application in flow channel regulation technology of high temperature and high salinity oil reservoirs; The high temperature is not less than 110° C.; and / or the high mineralization is not less than 200,000 mg / L.

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