An acoustic-magnetic coupling driven asymmetric tubular reservoir exploitation micro-nano robot, a preparation method and application thereof

Abstract

The application relates to the field of oil exploitation, in particular to a sound-magnetic coupling driven asymmetric tubular oil reservoir exploitation micro-nano robot and a preparation method and application thereof, which comprises the following steps: S1, a magnetic control sputtering method is used to sputter silver as a conductive layer on the back side of a porous polycarbonate template at a certain inclination angle; S2, an electrochemical deposition method is used to deposit gold in the template holes; S3, after the conductive silver layer and the template are dissolved, anhydrous ethanol is used for ultrasonic cleaning and centrifugal collection; S4, drying is carried out, a magnetic control sputtering method is used to sputter a nickel layer on the surface of the micro-nano robot, and an asymmetric tubular gold micro-nano robot with a sputtered nickel layer on the surface is obtained; and S5, the micro-nano robot is surface functionalized and modified by using n-dodecanethiol, and an asymmetric tubular oil reservoir exploitation micro-nano robot is obtained. The application can effectively improve the driving performance and control effect of the existing micro-nano robot, and realizes adsorption and transportation of oil.

Description

TECHNICAL FIELD

[0001] The application relates to the field of oil exploitation, in particular to a sound-magnetic coupling driven asymmetric tubular oil reservoir exploitation micro-nano robot and a preparation method and application thereof. BACKGROUND

[0002] The micro-nano robot is a machine between micrometer and nanometer scales, can convert external energy into mechanical energy of self motion, has the advantages of small size, large thrust-to-weight ratio, good controllability and strong expandability. By regulating and controlling the micro-nano robot to enter the complex micro-nano pore inside the oil reservoir formation, the remaining oil reservoir can be displaced and exploited, which can bring a new idea for the exploitation of low-permeability remaining oil reservoir. However, the existing micro-nano robot research is mostly based on the laboratory static water environment, the environmental structure is simple and the physical and chemical characteristic parameters are stable, so that the existing micro-nano robot has defects of weak driving capacity, single motion mode and poor control flexibility. Compared with this, the oil reservoir distribution environment has a complex structure, small pore throat diameter, high capillary pressure and large interfacial tension. The conventional design principle and driving control method of the micro-nano robot cannot meet the needs of oil reservoir displacement and exploitation.

[0003] Therefore, aiming at the displacement and exploitation needs of low-permeability remaining oil reservoir, the oil reservoir exploitation micro-nano robot based on coupled external energy field and the preparation method thereof are provided, which can effectively improve the driving performance and control effect of the existing micro-nano robot, realize the adsorption and transportation of oil and have a wide application prospect in the exploitation of low-permeability remaining oil reservoir. SUMMARY

[0004] The purpose of the application is to provide a sound-magnetic coupling driven asymmetric tubular oil reservoir exploitation micro-nano robot and a preparation method and application thereof, which can effectively improve the driving performance and control effect of the existing micro-nano robot and realize the adsorption and transportation of oil.

[0005] The purpose of the application is achieved by the following technical solutions.

[0006] The application provides a sound-magnetic coupling driven asymmetric tubular oil reservoir exploitation micro-nano robot preparation method, which comprises the following steps:

[0007] S1, a magnetron sputtering method is used to sputter silver as a conductive layer on the back side of a porous polycarbonate template at a certain inclination angle;

[0008] S2, an electrochemical deposition method is used to deposit gold in the template holes, so that a tubular gold micro-nano robot with an asymmetric structure is obtained in the template holes;

[0009] S3, after the conductive silver layer and the template are dissolved, the tubular gold micro-nano robot with the asymmetric structure dispersed in anhydrous ethanol is obtained by using anhydrous ethanol for ultrasonic cleaning and centrifugal collection;

[0010] S4. Dry the tubular gold micro-nano robots with asymmetric structure in anhydrous ethanol, and then use magnetron sputtering to sputter a nickel layer on the surface of the micro-nano robots to obtain asymmetric tubular gold micro-nano robots with a nickel layer sputtered on the surface.

[0011] S5. Surface functionalization of micro-nano robots was carried out using n-dodecyl mercaptan to obtain micro-nano robots for asymmetric tubular reservoir development.

[0012] Preferably, the porous polycarbonate template has a diameter of 25 mm, a thickness of 15 μm, and a pore diameter of 5 μm.

[0013] Preferably, in step S1, the sputtering tilt angle is 25-35°, more preferably 30°, and the thickness of the sputtered conductive layer is 150-200 nanometers, more preferably 200 nanometers.

[0014] Preferably, step S2 specifically involves using a platinum wire as the counter electrode, a silver / silver chloride wire as the reference electrode, and a sputtered silver conductive layer as the working electrode. Using a constant current method, a constant current of -2 to -6 mA, preferably -4 mA, is used to deposit gold in a gold deposition solution for 50-70 seconds, preferably 60 seconds, thereby obtaining a tubular gold micro / nano robot with an asymmetric structure within the template hole.

[0015] Preferably, the specific process flow for preparing the gold deposition solution is as follows: under the action of a magnetic stirrer, chloroauric acid tetrahydrate solution is added dropwise to sodium sulfite solution; while maintaining the stirring process, potassium citrate, ethylenediaminetetraacetic acid and potassium chloride are added sequentially to the resulting solution; sodium hydroxide solution is added dropwise to adjust the pH of the solution to 9, thus obtaining the gold deposition solution.

[0016] Preferably, step S3 specifically involves dissolving the conductive silver layer and the template using concentrated nitric acid and dichloromethane solutions, respectively, to obtain tubular gold micro-nano robots with an asymmetric structure released in the dichloromethane solution. Then, the tubular gold micro-nano robots with an asymmetric structure are ultrasonically cleaned three times and collected by centrifugation using anhydrous ethanol, ultimately obtaining tubular gold micro-nano robots with an asymmetric structure dispersed in anhydrous ethanol.

[0017] Preferably, step S4 specifically involves dropping an anhydrous ethanol solution containing tubular gold micro / nano robots with an asymmetric structure onto the surface of a glass slide, allowing it to diffuse uniformly and evaporate naturally in the air. The dried glass slide is then placed in a magnetron sputtering apparatus, and a nickel layer of 50-80 nanometers, preferably 50 nanometers thick, is sputtered at a vacuum of 0.08-0.1 Pa, preferably 0.1 Pa, using a power of 60-120 W, preferably 90 W, to obtain an asymmetric tubular gold micro / nano robot with a nickel layer sputtered on its surface.

[0018] Preferably, step S5 specifically involves preparing a dodecanethiol solution using anhydrous ethanol, transferring an asymmetric tubular gold micro / nano robot with a nickel layer sputtered on its surface into the dodecanethiol solution and immersing it for 10-12 hours, preferably 12 hours, and then collecting the immersed micro / nano robot by centrifugation to obtain the surface-hydrophobically modified asymmetric tubular micro / nano robot.

[0019] An acoustic-magnetic coupling driven asymmetric tubular oil reservoir development micro / nano robot was prepared using an acoustic-magnetic coupling driven asymmetric tubular oil reservoir development micro / nano robot fabrication method.

[0020] The application of an acoustic-magnetic coupling driven asymmetric tubular reservoir micro-nano robot in oil extraction.

[0021] The beneficial effects of this invention are as follows:

[0022] An asymmetric tubular micro / nanorobot composed of metallic materials was fabricated, capable of responding to and exhibiting motion behavior in response to external acoustic and magnetic field stimuli. The surface of the micro / nanorobot was functionalized using n-dodecyl mercaptan, endowing it with hydrophobic and oleophilic properties, effectively enabling the adsorption and transport of oil droplets. This asymmetric tubular oil reservoir development micro / nanorobot, driven by an acoustic-magnetic coupling field, relies on ultrasonic fields for propulsion and magnetic fields for directional control. Compared to other driving methods that rely on a single energy source, this asymmetric tubular micro / nanorobot exhibits faster movement speed and higher control precision, achieving the adsorption and transport of oil, and has broad application prospects in the field of oil exploration and development. Attached Figure Description

[0023] Figure 1 A schematic diagram of the fabrication process of a micro / nano robot for asymmetric tubular oil reservoir development;

[0024] Figure 2 Scanning electron microscope image and energy dispersive spectroscopy (EDS) image of a micro / nano robot for the exploitation of asymmetric tubular oil reservoirs;

[0025] Figure 3 The image shows the test results of the contact angle of the materials used to construct micro-nano robots.

[0026] Figure 4 A diagram showing the components of an experimental device for driving and controlling a micro-nano robot in the development of asymmetric tubular oil reservoirs.

[0027] Figure 5 A schematic diagram illustrating the drive and control mechanism of a micro-nano robot for the exploitation of asymmetric tubular oil reservoirs and its oil production process.

[0028] Figure 6 This is an experimental diagram of the drive and control of a micro-nano robot for the exploitation of asymmetric tubular oil reservoirs.

[0029] Figure 7This is an experimental diagram of a micro-nano robot for oil production in asymmetric tubular reservoirs.

[0030] In the picture:

[0031] 1-Microscope; 2-Helmholtz coil; 3-Borosilicate glass slide; 4-Silicon wafer; 5-Ultrasonic transducer; 6-Polyimide patch; 7-Wire. Detailed Implementation

[0032] like Figure 1 As shown, a detailed description is provided of the fabrication method of a micro / nano robot for asymmetric tubular oil reservoir development driven by acoustic-magnetic coupling:

[0033] Example 1:

[0034] A method for fabricating a micro / nano robot for asymmetric tubular oil reservoir development driven by acoustic-magnetic coupling includes the following steps:

[0035] S1. Using magnetron sputtering, silver is sputtered as a conductive layer on the back side of a porous polycarbonate template at a certain tilt angle; wherein, the porous polycarbonate template has a diameter of 25 mm, a thickness of 15 μm, and a pore diameter of 5 μm; the sputtering tilt angle is 25°, and the thickness of the sputtered conductive layer is 150 nm.

[0036] S2. Gold is deposited in the template wells using an electrochemical deposition method to obtain tubular gold micro / nano robots with an asymmetric structure. Specifically, a platinum wire is used as the counter electrode, a silver / silver chloride wire as the reference electrode, and a sputtered silver conductive layer as the working electrode. A constant current of -4mA is used to deposit gold in the gold deposition solution for 50 seconds using a constant current method, thus obtaining tubular gold micro / nano robots with an asymmetric structure in the template wells. The specific process for preparing the gold deposition solution is as follows: under the action of a magnetic stirrer, 30 mL of 0.1 mol / L chloroauric acid tetrahydrate solution is added dropwise to 30 mL of 1.1 mol / L sodium sulfite solution; while maintaining stirring, 4.8 g of potassium citrate, 2.4 g of ethylenediaminetetraacetic acid, and 3.6 g of potassium chloride are added sequentially to the resulting solution; a 10 mol / L sodium hydroxide solution is added dropwise to adjust the pH of the solution to 9, thus obtaining the gold deposition solution.

[0037] S3. After dissolving the conductive silver layer and template, ultrasonic cleaning and centrifugation are performed using anhydrous ethanol to obtain tubular gold micro-nano robots with asymmetric structures dispersed in anhydrous ethanol. Specifically, concentrated nitric acid and dichloromethane solutions with a concentration of 8 mol / L are used to dissolve the conductive silver layer and template, respectively, to obtain tubular gold micro-nano robots with asymmetric structures released in dichloromethane solution. Then, the tubular gold micro-nano robots with asymmetric structures are ultrasonically cleaned and centrifuged three times using anhydrous ethanol to finally obtain tubular gold micro-nano robots with asymmetric structures dispersed in anhydrous ethanol.

[0038] S4. The tubular gold micro / nano robots with asymmetric structures in anhydrous ethanol are dried, and a nickel layer is sputtered onto the surface of the micro / nano robots using magnetron sputtering to obtain asymmetric tubular gold micro / nano robots with a nickel layer sputtered on the surface. Specifically, an anhydrous ethanol solution containing tubular gold micro / nano robots with asymmetric structures is dropped onto the surface of a glass slide, allowing it to diffuse uniformly and evaporate naturally in the air. The dried glass slide is then placed in a magnetron sputtering device, and a 65-nanometer-thick nickel layer is sputtered using a power of 60W under a vacuum of 0.08 Pa to obtain asymmetric tubular gold micro / nano robots with a nickel layer sputtered on the surface.

[0039] S5. Surface functionalization modification of micro-nano robots using n-dodecathiol was used to obtain asymmetric tubular oil reservoir development micro-nano robots. Specifically, an anhydrous ethanol solution of n-dodecathiol was prepared, and an asymmetric tubular gold micro-nano robot with a nickel layer sputtered on its surface was transferred to 50 mL of a 0.5 mmol / L n-dodecathiol solution and soaked for 10 hours. The soaked micro-nano robot was collected by centrifugation to obtain the surface-hydrophobically modified asymmetric tubular micro-nano robot.

[0040] Example 2:

[0041] A method for fabricating a micro / nano robot for asymmetric tubular oil reservoir development driven by acoustic-magnetic coupling includes the following steps:

[0042] S1. Using magnetron sputtering, silver is sputtered as a conductive layer on the back side of a porous polycarbonate template at a certain tilt angle; wherein, the porous polycarbonate template has a diameter of 25 mm, a thickness of 15 μm, and a pore diameter of 5 μm; the sputtering tilt angle is 30°, and the thickness of the sputtered conductive layer is 200 nm.

[0043] S2. Gold is deposited in the template wells using an electrochemical deposition method to obtain tubular gold micro / nano robots with an asymmetric structure. Specifically, a platinum wire is used as the counter electrode, a silver / silver chloride wire as the reference electrode, and a sputtered silver conductive layer as the working electrode. A constant current of -4mA is used to deposit gold in the deposition solution for 60 seconds using a constant current method, thus obtaining tubular gold micro / nano robots with an asymmetric structure in the template wells. The specific process for preparing the gold deposition solution is as follows: under the action of a magnetic stirrer, 30 mL of 0.1 mol / L chloroauric acid tetrahydrate solution is added dropwise to 30 mL of 1.1 mol / L sodium sulfite solution; while maintaining stirring, 4.8 g of potassium citrate, 2.4 g of ethylenediaminetetraacetic acid, and 3.6 g of potassium chloride are added sequentially to the resulting solution; a 10 mol / L sodium hydroxide solution is added dropwise to adjust the pH of the solution to 9, thus obtaining the gold deposition solution.

[0044] S3. After dissolving the conductive silver layer and template, ultrasonic cleaning and centrifugation are performed using anhydrous ethanol to obtain tubular gold micro-nano robots with asymmetric structures dispersed in anhydrous ethanol. Specifically, concentrated nitric acid and dichloromethane solutions with a concentration of 8 mol / L are used to dissolve the conductive silver layer and template, respectively, to obtain tubular gold micro-nano robots with asymmetric structures released in dichloromethane solution. Then, the tubular gold micro-nano robots with asymmetric structures are ultrasonically cleaned and centrifuged three times using anhydrous ethanol to finally obtain tubular gold micro-nano robots with asymmetric structures dispersed in anhydrous ethanol.

[0045] S4. The tubular gold micro / nano robots with asymmetric structures in anhydrous ethanol are dried, and a nickel layer is sputtered onto the surface of the micro / nano robots using magnetron sputtering to obtain asymmetric tubular gold micro / nano robots with a nickel layer sputtered on the surface. Specifically, an anhydrous ethanol solution containing tubular gold micro / nano robots with asymmetric structures is dropped onto the surface of a glass slide, allowing it to diffuse uniformly and evaporate naturally in the air. The dried glass slide is then placed in a magnetron sputtering device, and a 50-nanometer-thick nickel layer is sputtered using a power of 90W under a vacuum of 0.1 Pa to obtain asymmetric tubular gold micro / nano robots with a nickel layer sputtered on the surface.

[0046] S5. Surface functionalization modification of micro-nano robots using n-dodecathiol was used to obtain asymmetric tubular oil reservoir development micro-nano robots. Specifically, an anhydrous ethanol solution of n-dodecathiol was prepared, and an asymmetric tubular gold micro-nano robot with a nickel layer sputtered on its surface was transferred to 50 mL of a 0.5 mmol / L n-dodecathiol solution and soaked for 12 hours. The soaked micro-nano robot was collected by centrifugation to obtain the surface-hydrophobically modified asymmetric tubular micro-nano robot.

[0047] Example 3:

[0048] A method for fabricating a micro / nano robot for asymmetric tubular oil reservoir development driven by acoustic-magnetic coupling includes the following steps:

[0049] S1. Using magnetron sputtering, silver is sputtered as a conductive layer on the back side of a porous polycarbonate template at a certain tilt angle; wherein, the porous polycarbonate template has a diameter of 25 mm, a thickness of 15 μm, and a pore diameter of 5 μm; the sputtering tilt angle is 35°, and the thickness of the sputtered conductive layer is 175 nm.

[0050] S2. Gold is deposited in the template wells using an electrochemical deposition method to obtain tubular gold micro / nano robots with an asymmetric structure. Specifically, a platinum wire is used as the counter electrode, a silver / silver chloride wire as the reference electrode, and a sputtered silver conductive layer as the working electrode. A constant current of -4mA is used to deposit gold in the deposition solution for 70 seconds using a constant current method, thus obtaining tubular gold micro / nano robots with an asymmetric structure in the template wells. The specific process for preparing the gold deposition solution is as follows: under the action of a magnetic stirrer, 30 mL of 0.1 mol / L chloroauric acid tetrahydrate solution is added dropwise to 30 mL of 1.1 mol / L sodium sulfite solution; while maintaining stirring, 4.8 g of potassium citrate, 2.4 g of ethylenediaminetetraacetic acid, and 3.6 g of potassium chloride are added sequentially to the resulting solution; a 10 mol / L sodium hydroxide solution is added dropwise to adjust the pH of the solution to 9, thus obtaining the gold deposition solution.

[0051] S3. After dissolving the conductive silver layer and template, ultrasonic cleaning and centrifugation are performed using anhydrous ethanol to obtain tubular gold micro-nano robots with asymmetric structures dispersed in anhydrous ethanol. Specifically, concentrated nitric acid and dichloromethane solutions with a concentration of 8 mol / L are used to dissolve the conductive silver layer and template, respectively, to obtain tubular gold micro-nano robots with asymmetric structures released in dichloromethane solution. Then, the tubular gold micro-nano robots with asymmetric structures are ultrasonically cleaned and centrifuged three times using anhydrous ethanol to finally obtain tubular gold micro-nano robots with asymmetric structures dispersed in anhydrous ethanol.

[0052] S4. The tubular gold micro / nano robots with asymmetric structures in anhydrous ethanol are dried, and a nickel layer is sputtered onto the surface of the micro / nano robots using magnetron sputtering to obtain asymmetric tubular gold micro / nano robots with a nickel layer sputtered on the surface. Specifically, an anhydrous ethanol solution containing tubular gold micro / nano robots with asymmetric structures is dropped onto the surface of a glass slide, allowing it to diffuse uniformly and evaporate naturally in the air. The dried glass slide is then placed in a magnetron sputtering device, and an 80-nanometer-thick nickel layer is sputtered using a power of 120W under a vacuum of 0.09 Pa to obtain asymmetric tubular gold micro / nano robots with a nickel layer sputtered on the surface.

[0053] S5. Surface functionalization modification of micro-nano robots using n-dodecathiol was used to obtain asymmetric tubular oil reservoir development micro-nano robots. Specifically, an anhydrous ethanol solution of n-dodecathiol was prepared, and an asymmetric tubular gold micro-nano robot with a nickel layer sputtered on its surface was transferred to 50 mL of a 0.5 mmol / L n-dodecathiol solution and soaked for 11 hours. The soaked micro-nano robot was collected by centrifugation to obtain the surface-hydrophobically modified asymmetric tubular micro-nano robot.

[0054] In embodiments one to three above, the asymmetric structure of the tubular gold micro / nanorobot is formed due to the sputtering of a conductive silver layer at a certain tilt angle, resulting in an asymmetric distribution and the formation of sharp points within the template apertures. Furthermore, during electrochemical deposition, charge accumulates at the tips of the silver layer, leading to uneven gold deposition rates within the template apertures, ultimately resulting in the formation of the asymmetric structure of the micro / nanorobot. By controlling the magnetron sputtering and electrochemical deposition parameters, the size and structure of the micro / nanorobot can be controlled, ultimately achieving customized fabrication of the micro / nanorobot. The bevel angle of the asymmetric tubular micro / nanorobot can be controlled by the tilt angle of the magnetron sputtering; a larger magnetron sputtering tilt angle results in a larger bevel angle. The central angle of the micro / nanorobot can be controlled by the magnitude of the electrochemical deposition current; a larger current results in a larger central angle. The height of the micro / nanorobot can be controlled by the electrochemical deposition time; a longer deposition time results in a higher height.

[0055] like Figures 2-3 As shown, a detailed description is provided of the micro / nano robot for asymmetric tubular oil reservoir development driven by an acoustic-magnetic coupling field:

[0056] The asymmetric tubular micro / nano robots were characterized using scanning electron microscopy and energy dispersive spectroscopy. The characterization results are as follows: Figure 2 As shown. The contact angle of the materials constituting the micro / nano robot was tested using a contact angle measuring instrument, and the test results are as follows. Figure 3 As shown in the figure. Analysis and test results show that after surface modification with n-dodecyl mercaptan, the contact angle increased from 73.5 degrees to 129.6 degrees, exhibiting significant hydrophobicity, which can be used to achieve effective adsorption of oil droplets.

[0057] like Figure 4 As shown, a detailed description is provided of the experimental setup for the drive control of a micro / nano robot for asymmetric tubular oil reservoir development driven by an acoustic-magnetic coupling field:

[0058] This invention proposes a drive and control experimental device for a micro / nano robot driven by an acoustic-magnetic coupling field in the exploitation of asymmetric tubular oil reservoirs. It mainly consists of three parts: a microscope, a magnetic field generator, and an ultrasonic field generator. The magnetic field generator comprises two sets of Helmholtz coils. A 4V DC signal is generated by a signal generator, amplified four times by a power amplifier, and then input into the two sets of Helmholtz coils. By controlling the relative amplitudes of the electrical signals input to the two sets of Helmholtz coils, the relative magnitude of the generated magnetic field strength is controlled, ultimately producing a uniform magnetic field in any direction within a plane. The ultrasonic field generator mainly consists of an ultrasonic transducer, a borosilicate glass plate, a silicon wafer, and a polyimide patch. A 3MHz, 10V sine wave signal is generated by a signal generator, amplified twice by a power amplifier, and then input into the ultrasonic transducer. Based on the inverse piezoelectric effect, an ultrasonic field is generated in three-dimensional space. The ultrasonic transducer is attached to the back of the silicon wafer, and the generated ultrasonic field propagates through the silicon wafer to reduce losses during ultrasonic wave transmission. A 250 μm thick polyimide patch is attached to the front side of the silicon wafer, with a 3 mm diameter cylindrical hole in the center to serve as the experimental area for micro- and nano-robots. A borosilicate glass plate is placed above the patch to reflect sound waves and create an ultrasonic standing wave field in the micro- and nano-robot experimental area.

[0059] Due to the asymmetric structure of the micro-nano robots, they can respond to external sound field stimuli and exhibit motion behavior. Simultaneously, because the surface of the micro-nano robots is sputtered with magnetic nickel, they can respond to external magnetic field stimuli and exhibit turning behavior. Under the influence of an acoustic-magnetic coupling field, the micro-nano robots used in asymmetric tubular oil reservoir extraction can exhibit high-speed motion. By controlling the amplitude of the applied sound field and the direction of the magnetic field, the speed and direction of the micro-nano robots can be controlled.

[0060] like Figure 5 As shown, a detailed description is provided of micro-nano robots for oil extraction in asymmetric tubular reservoirs driven by acoustic-magnetic coupling fields:

[0061] Because the surface of the micro-nano robot is modified with n-dodecyl mercaptan, it possesses strong hydrophobic and oleophilic properties, enabling effective adsorption of oil droplets in solution. Furthermore, due to the controllable motion characteristics of the proposed micro-nano robot, the controlled transport of oil droplets can be achieved by controlling the characteristic parameters of the applied external coupling field. By mixing the micro-nano robot with a displacement solution and injecting it into a low-permeability reservoir, and controlling the applied external coupling field, the remaining oil in the low-permeability reservoir can be adsorbed and transported to the production well, ultimately realizing the oil extraction function.

[0062] Specifically, this invention proposes a micro / nano robot for asymmetric tubular oil reservoir extraction driven by an acoustic-magnetic coupling field, which has broad application prospects in oil extraction. In the oil displacement extraction process, firstly, the micro / nano robot is mixed with the displacement solution and injected through an injection well; secondly, an acoustic-magnetic coupling field is applied in the formation. Under the action of the acoustic-magnetic coupling field, the micro / nano robot moves in the formation environment, achieving effective adsorption, transportation, and displacement extraction of remaining oil; finally, the micro / nano robot is controlled to flow out of the production well with the displacement solution, and the produced solution undergoes solid-liquid separation to obtain the extracted oil. Because the proposed micro / nano robot itself has an asymmetric structure, under the action of an ultrasonic field, one end of the micro / nano robot converges sound field energy to form a high sound pressure region, while the other end scatters sound field energy to form a low sound pressure region. This generates a sound pressure gradient around the micro / nano robot, further producing a large sound radiation force, propelling the micro / nano robot to move at high speed in the formation environment. Simultaneously, because the surface of the micro / nano robot is sputtered with magnetic nickel, it can respond to the stimulation of an external magnetic field. By adjusting the direction of the externally applied magnetic field, it is possible to achieve motion navigation of micro- and nano-robots in complex geological environments.

[0063] like Figure 6 As shown, experiments were conducted to verify the motion capability and controllability of the micro / nano robot for asymmetric tubular oil reservoir development under an acoustic-magnetic coupling field:

[0064] First, when no external physical field is applied, the micro-nano robot remains stationary and floats in the solution environment of the experimental area. Second, a 3MHz, 10V AC signal amplified twice is passed into the ultrasonic transducer, and a 4V DC signal amplified four times is passed into the Helmholtz coil, activating the acousto-magnetic coupling field. The micro-nano robot rapidly transitions from a stationary state to a moving state, exhibiting relatively fast motion behavior. Third, by changing the intensity of the applied ultrasonic field, the movement speed of the micro-nano robot can be controlled. The movement speed of the micro-nano robot increases with the increase of the amplitude of the electrical signal passed into the ultrasonic transducer. Finally, by controlling the relative magnitudes of the electrical signal amplitudes input to the two sets of Helmholtz coils, and thus controlling the direction of the applied magnetic field, precise control of the movement direction and trajectory of the micro-nano robot can be achieved.

[0065] like Figure 7 As shown, experiments were conducted to verify the ability of the micro / nano robot for asymmetric tubular oil reservoir development to adsorb and transport oil droplets in a microscale environment:

[0066] By functionalizing the surface of the micro-nano robot with n-dodecyl mercaptan, it exhibits strong hydrophobic and oleophilic properties in microscale oil-water environments, enabling stable adsorption of multiple oil droplets. Simultaneously, under the influence of an acoustic-magnetic coupling field, the micro-nano robot can effectively carry multiple oil droplets and exhibit relatively rapid motion. By controlling the intensity of the applied ultrasonic field, the robot's speed can be controlled; by controlling the direction of the externally applied magnetic field, its motion direction can be adjusted, further enabling trajectory control and obstacle avoidance control in complex microscale environments. Experiments demonstrate the controllable transport capability of the micro-nano robot for oil droplets in complex microscale environments, thus proving its broad application prospects in the field of oil extraction.

Claims

1. A method for fabricating a micro / nano robot for asymmetric tubular oil reservoir development driven by acoustic-magnetic coupling, characterized in that: The method comprises the following steps: S1, using a magnetron sputtering method, sputtering silver as a conductive layer at a certain inclined angle on the back side of a porous polycarbonate template; the sputtering inclined angle is 25-35°, and the sputtering conductive layer thickness is 150-200 nm; S2, using an electrochemical deposition method, depositing gold in the template holes, so as to obtain a tubular gold micro-nano robot with an asymmetric structure in the template holes; using a platinum wire as a counter electrode, a silver / silver chloride wire as a reference electrode, and the sputtered silver conductive layer as a working electrode, using a constant current method, depositing gold in the gold deposition solution at a constant current of -2 to -6 mA for 50-70 seconds, so as to obtain a tubular gold micro-nano robot with an asymmetric structure in the template holes; S3, after dissolving the conductive silver layer and the template, using anhydrous ethanol for ultrasonic cleaning and centrifugal collection, so as to obtain a tubular gold micro-nano robot with an asymmetric structure dispersed in anhydrous ethanol; S4, drying the tubular gold micro-nano robot with an asymmetric structure in anhydrous ethanol, using a magnetron sputtering method to sputter a nickel layer on the surface of the micro-nano robot, so as to obtain an asymmetric tubular gold micro-nano robot with a sputtered nickel layer on the surface; S5, using n-dodecanethiol to functionalize and modify the surface of the micro-nano robot, so as to obtain an asymmetric tubular oil reservoir exploitation micro-nano robot.

2. The method of claim 1, wherein: The diameter of the porous polycarbonate template is 25 mm, the thickness is 15 microns, and the pore diameter is 5 microns.

3. The method of claim 1, wherein: The specific process flow for preparing the gold deposition solution is as follows: under the action of a magnetic stirrer, a chloroauric acid solution is added dropwise into a sodium sulfite solution; The stirring process is maintained, and potassium citrate, ethylenediaminetetraacetic acid, and potassium chloride are sequentially added to the obtained solution; a sodium hydroxide solution is added dropwise to adjust the pH of the solution to 9, so as to obtain the gold deposition solution.

4. The method of claim 1, wherein: The step S3 is specifically using concentrated nitric acid and dichloromethane solution to dissolve the conductive silver layer and the template respectively, so as to obtain a tubular gold micro-nano robot with an asymmetric structure released in the dichloromethane solution, then using anhydrous ethanol to ultrasonically clean and centrifugally collect the tubular gold micro-nano robot with an asymmetric structure three times, and finally obtaining a tubular gold micro-nano robot with an asymmetric structure dispersed in anhydrous ethanol.

5. The method of claim 1, wherein: The step S4 is specifically that the anhydrous ethanol solution containing the tubular gold micro-nano robot with an asymmetric structure is dropped onto the surface of a glass sheet, so as to uniformly diffuse and naturally evaporate and dry in the air; the dried glass sheet is placed in a magnetron sputtering device, a 50-80 nm thick nickel layer is sputtered under a vacuum degree of 0.08-0.1 Pa and using a power of 60-120 W, so as to obtain an asymmetric tubular gold micro-nano robot with a sputtered nickel layer on the surface.

6. The method of claim 1, wherein: The step S5 is specifically that anhydrous ethanol is used to prepare a n-dodecanethiol solution, the asymmetric tubular gold micro-nano robot with a sputtered nickel layer is transferred into the n-dodecanethiol solution and soaked for 10-12 hours, and the soaked micro-nano robot is centrifugally collected, so as to obtain an asymmetric tubular micro-nano robot with a hydrophobic modified surface.

7. An asymmetric tubular oil reservoir exploitation micro-nano robot driven by acoustic-magnetic coupling, which is prepared by using the preparation method of any one of claims 1-6.

8. The use of the magneto-acoustic coupled driving asymmetric tubular reservoir exploitation micro-nano robot according to claim 7 in oil exploitation.

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