A testing device and method for gas hydrate surface nanolayer fluidity

Abstract

The application provides a device and method for testing the fluidity of a gas hydrate surface nanometer liquid film, and relates to the technical field of geological engineering. The device comprises a glove box, a base fixedly arranged in the glove box, a cold and hot table movably arranged on the base, a lifter connected to the cold and hot table, a sample table arranged on the cold and hot table, a pressure vessel detachably connected to the sample table, and a scanning probe microscope used for obtaining the probe jump distance in the process that the probe contacts and penetrates through the gas hydrate surface nanometer liquid film, obtaining the change of the thickness of the gas hydrate surface nanometer liquid film with time, and obtaining the fluidity of the gas hydrate surface nanometer liquid film. The application has the beneficial effects that the synthesis, stability and surface nanometer liquid film flow of the gas hydrate are met, and the accurate measurement of the thickness of the gas hydrate surface nanometer liquid film and the flow analysis are realized.

Description

Technical Field

[0001] The present invention relates to the field of geological engineering technology, and in particular to a device and method for testing the fluidity of nano-liquid films on the surface of gas hydrates. Background Art

[0002] Gas hydrates are solid compounds with a cage-like structure formed by water molecules and gas molecules such as methane and propane under high pressure and low temperature conditions. Natural gas hydrates are the most well-known of these. Under the influence of continuous drilling and production activities, the surface crystals of gas hydrates undergo a spontaneous phase transition and decomposition, producing a nanometer-thick amorphous transitional liquid film. This nano-liquid film on the surface of the gas hydrate flows under the influence of reservoir inclination, directly affecting the contact, friction, and adhesion interactions between gas hydrate particles and between gas hydrates and sediment particles. This is a key cause of adverse responses such as degraded wellbore stability, instability of gas hydrate-bearing reservoirs, and formation subsidence during drilling and production, hindering the efficient extraction and production safety of gas hydrates.

[0003] To overcome this engineering bottleneck, understanding the fluidity of the nanofilm on the surface of gas hydrates, particularly the evolution of its fluidity and thickness during reservoir instability due to tilt, is crucial for regulating the interactions between gas hydrate particles, optimizing safety risk mitigation strategies for drilling and production projects, and promoting the safe development of gas hydrates. However, because maintaining gas hydrate stability requires low temperatures and high pressures, and the sample stage must be able to tilt freely to simulate reservoir inclination, existing scanning probe microscopes are unable to accurately measure the thickness of the nanofilm on the surface of gas hydrates, let alone quantitatively evaluate its fluidity. Summary of the Invention

[0004] In view of this, in order to solve the problem that existing scanning probe microscopes cannot accurately measure the thickness of nano-liquid films on the surface of gas hydrates, embodiments of the present invention provide a device and method for testing the fluidity of nano-liquid films on the surface of gas hydrates.

[0005] An embodiment of the present invention provides a device for testing the fluidity of a nano-liquid film on a gas hydrate surface, comprising:

[0006] glove box;

[0007] a base, which is fixedly disposed in the glove box;

[0008] A hot and cold stage, which is movably arranged on the base;

[0009] A lifter connected to the hot and cold stages to drive the hot and cold stages to tilt to a desired angle;

[0010] The sample stage is placed on the hot and cold stage, and the hot and cold stage is used to cool the sample stage to the required temperature.

[0011] A pressure autoclave, which is arranged above the hot and cold stages and can be detachably connected to the sample stage, for applying a required air pressure to the sample stage;

[0012] And a scanning probe microscope, the probe of the scanning probe microscope is used to contact the gas hydrate sample generated on the sample stage, obtain the probe jumping distance in the process of the probe contacting and passing through the nano-liquid film on the surface of the gas hydrate, and the change of the thickness of the nano-liquid film on the surface of the gas hydrate with time can be obtained from the probe jumping distance, so that the fluidity of the nano-liquid film on the surface of the gas hydrate can be obtained according to the thickness of the nano-liquid film on the surface of the gas hydrate obtained at different times.

[0013] Furthermore, a card plate is provided at the bottom of the hot and cold table, one end of the card plate is supported on the base, and the other end is provided with a bent plug plate, the lifter is arranged on the base and connected to the card plate, and a U-shaped bolt seat is provided on one side of the base, the plug plate can be movably inserted into the bolt seat, and the bolt seat is provided with a locking bolt, and the locking bolt can lock the plug plate.

[0014] Furthermore, the scanning probe microscope further includes an optical microscope and a scanning driver for driving the probe to move.

[0015] Furthermore, a semiconductor cooler is provided on the hot and cold stage, and the sample stage is arranged on the semiconductor cooler.

[0016] Furthermore, the glove box is a dehumidification glove box with a molecular sieve drying tank.

[0017] Furthermore, the pressure autoclave is provided with a quick connector at the upper end and a flange at the lower end, the quick connector is used to connect to an external air source through an air inlet pipe, and the flange is connected to the sample stage.

[0018] Furthermore, a sealing ring is provided between the flange and the sample stage.

[0019] In addition, an embodiment of the present invention further provides a method for testing the fluidity of a nano-liquid film on a gas hydrate surface, using the above-mentioned testing device for the fluidity of a nano-liquid film on a gas hydrate surface, and further comprising the following steps:

[0020] S1, dripping ultrapure water onto the sample stage, adjusting the temperature of the sample stage by the hot and cold stage, and inputting gas at a required pressure into the sample stage by the autoclave to prepare a gas hydrate sample;

[0021] S2, adjusting the tilt of the sample stage to a desired angle by the lifter;

[0022] S3, disassembling and removing the autoclave from the upper portion of the sample stage, and moving the probe of the scanning probe microscope so that the probe is close to the gas hydrate sample;

[0023] S4, recording the process of the probe contacting the gas hydrate sample and passing through the nano-liquid film on the surface of the gas hydrate, and obtaining the probe jumping distance in this process;

[0024] S5. Calibrate the systematic error of the probe jump distance recorded by the scanning probe microscope to obtain the change of the nano-liquid film thickness on the gas hydrate surface with time;

[0025] S6. Substituting the thickness of the nano-liquid film on the surface of the gas hydrate obtained at different times into the calculation formula, the fluidity of the nano-liquid film on the surface of the gas hydrate is obtained.

[0026] Furthermore, in step S5, the formula for calculating the systematic error Δd of the probe jump distance recorded by the scanning probe microscope is as follows:

[0027]

[0028] Where: H is the Hamaker constant of gas hydrate, R is the tip radius of the probe; k is the elastic coefficient of the probe.

[0029] Furthermore, it is characterized in that: the calculation formula of the fluidity of the nano-liquid film on the surface of the gas hydrate in step S6 is:

[0030]

[0031] Where: N represents the total number of nano-liquid film thickness data on the surface of gas hydrates, d N represents the probe jump distance after calibration of the Nth group; d a Represents the average of the probe jump distances after calibration for all groups.

[0032] The beneficial effects brought about by the technical solution provided by the embodiments of the present invention are:

[0033] 1. The present invention provides a testing device for the fluidity of nano-liquid films on the surface of gas hydrates. The device provides suitable temperature and pressure conditions in the sample stage through a hot and cold stage and a pressure autoclave to synthesize gas hydrates. The tilt angle of the sample stage is adjusted by a lifter to achieve the goal of simulating the flow of nano-liquid films on the surface of gas hydrates caused by reservoir tilt. At the same time, it meets the requirements of gas hydrate synthesis, stabilization and surface nano-liquid film flow, and can realize accurate measurement of the thickness of nano-liquid films on the surface of gas hydrates and fluidity analysis at the nanoscale.

[0034] 2. The present invention provides a method for testing the fluidity of nano-liquid films on the surface of gas hydrates. A testing device for the fluidity of nano-liquid films on the surface of gas hydrates is used to prepare gas hydrate samples and simulate the flow of nano-liquid films on the surface of gas hydrates caused by reservoir inclination. The thickness of the nano-liquid films on the surface of gas hydrates is measured using a scanning probe microscope, and a mathematical formula for correcting system errors is substituted into the formula to achieve quantitative characterization of the fluidity of nano-liquid films on the surface of gas hydrates. This method breaks through the bottleneck that existing testing devices and methods cannot accurately measure and analyze the fluidity of nano-liquid films on the surface of gas hydrates, and is of great significance for optimizing gas hydrate development design and improving drilling and production safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of a test device for the fluidity of a nano-liquid film on the surface of a gas hydrate according to the present invention;

[0036] Figure 2 The present invention is a schematic diagram of the movement of a probe in a test of the fluidity of a nano-liquid film on the surface of a gas hydrate.

[0037] In the figure: 1. Hot and cold stage; 2. Semiconductor refrigerator; 3. Sample stage; 4. Probe; 5. Scanning driver; 6. Scanning probe microscope; 7. Optical microscope; 8. Screws; 9. Pressure vessel; 10. Air inlet pipe; 11. Temperature sensor; 12. Lifter; 13. Insert plate; 14. Locking bolt; 15. Limit baffle; 16. Base; 17. Glove box; 18. Card plate; 19. Bolt seat. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the present invention more apparent, embodiments of the present invention will be further described below with reference to the accompanying drawings. The following describes a preferred embodiment of the present invention among multiple possible embodiments, which is intended to provide a basic understanding of the present invention but is not intended to identify the key or decisive elements of the present invention or to limit the scope of protection.

[0039] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0040] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0041] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in the subsequent drawings. At the same time, it should be understood that for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual scale.

[0042] It should be noted that, unless otherwise specified or limited, the terms "mounted" and "connected" should be understood broadly. For example, they can refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0043] Please refer to Figure 1 An embodiment of the present invention provides a device for testing the fluidity of a nano-liquid film on the surface of a gas hydrate, which mainly includes a glove box 17, a base 16, a hot and cold stage 1, a lifter 12, a sample stage 3, a pressure autoclave 9 and a scanning probe microscope 6.

[0044] The glove box 17 is used to provide a dry and stable testing environment. In this embodiment, the glove box 17 is a dehumidified glove box with a molecular sieve drying tank. The dehumidified glove box drives the air inside the glove box through the molecular sieve drying tank. The high-quality porous molecular sieve inside the dehumidified glove box 17 absorbs moisture from the air inside the glove box 17, keeping the dew point below -70°C and preventing moisture condensation on the surface of the gas hydrates.

[0045] The base 16 is fixedly arranged in the glove box 17. The hot and cold table 1 is movably arranged on the base 16. The sample stage 3 is arranged on the hot and cold table 1, and the hot and cold table 1 is used to cool the sample stage 3 to the required temperature. Here, a semiconductor refrigerator 2 is provided on the hot and cold table 1, and the sample stage 3 is arranged on the semiconductor refrigerator 2. The center of the sample stage 3 is a circular boss, which is 0.5mm higher than the semiconductor refrigerator 2. The interior of the semiconductor refrigerator 2 is a multi-stage cooling plate superposition structure with a temperature control range of -60°C to 40°C and a temperature control accuracy of ±0.01°C. It has the advantages of fast cooling speed and high temperature control accuracy. A temperature sensor 11 is also provided on one side of the semiconductor refrigerator 2 to monitor the temperature of the sample stage 3.

[0046] The lifter 12 is connected to the hot and cold table 1 to drive the hot and cold table 1 to tilt to the desired angle. Specifically, a card plate 18 is provided at the bottom of the hot and cold table 1, and the temperature sensor 11 and the semiconductor refrigerator 2 are fixed to the upper surface of the card plate 18 by screws 8. One end of the card plate 18 is supported on the base 16, and the other end is provided with a bent plug plate 13. The lifter 12 is detachably arranged on the base 16 and connected to the card plate 18. A U-shaped bolt seat 19 is provided on one side of the base 16, and the bolt seat 19 is fixed to the end of the base 16 by a limit baffle 15. The plug plate 13 can be movably inserted into the bolt seat 19, and the bolt seat 19 is provided with a locking bolt 14, and the locking bolt 14 can lock the plug plate 13.

[0047] Thus, when the locking bolt 14 is loosened, the lifter 12 can drive the clamping plate 18 to move up and down, thereby moving the hot and cold table 1 up and down, thereby adjusting the hot and cold table 1 to a desired angle, such as 0° to 45°. Tightening the locking bolt 14 can then stabilize the hot and cold table 1.

[0048] The autoclave 9 is positioned above the hot and cold stages 1 and is detachably connected to the sample stage 3 to apply the desired air pressure to the sample stage 3. Specifically, the autoclave 9 is a hollow cylindrical chamber with a quick connector at the top and a flange at the bottom. The quick connector is used to connect to an external air source via an air inlet pipe 10, and the flange is connected to the sample stage 3.

[0049] The autoclave 9 generally has a hollow cylindrical cavity in the middle, with a diameter slightly larger than the central circular boss of the sample stage 3. The flange of the autoclave 9 and the sample stage 3 can be connected by bolts. A sealing ring such as a rubber ring can be added between the two to improve the sealing. The pressure range of the cavity inside the autoclave 9 is 0 to 20 MPa.

[0050] The scanning probe microscope 6, the probe 4 of the scanning probe microscope 6 is used to contact the gas hydrate sample generated on the sample stage 3, and obtain the probe jumping distance in the process of the probe 4 contacting and passing through the nano-liquid film on the surface of the gas hydrate. The change of the thickness of the nano-liquid film on the surface of the gas hydrate with time can be obtained from the probe jumping distance, so that the fluidity of the nano-liquid film on the surface of the gas hydrate can be obtained according to the thickness of the nano-liquid film on the surface of the gas hydrate obtained at different times.

[0051] The scanning probe microscope 6 further comprises an optical microscope 7, and a scanning driver 5 driving the probe 4 to move. The optical microscope 7 is arranged above the sample stage 3, and the magnification can be up to 50 times. The probe 4 is mounted on the front end of the scanning driver 5, and the scanning driver 5 can drive the probe 4 to move according to the pre-set movement track. The scanning driver 5 can be mounted and dismounted with different types of probes 4.

[0052] In addition, the embodiment of the present application also provides a testing method for the fluidity of the gas hydrate surface nanometer liquid film, which uses the testing device for the fluidity of the gas hydrate surface nanometer liquid film and further comprises the following steps.

[0053] S1, dripping ultrapure water on the sample stage 3, adjusting the temperature of the sample stage 3 through the cold and hot stage 1, and inputting the gas with the required pressure into the sample stage 3 through the pressure vessel 9 to prepare a gas hydrate sample.

[0054] Specifically, the center circular boss of the sample stage 3 is wiped clean with a dust-free paper, and two drops of ultrapure water, about 30 microliters, are dripped thereon; the temperature of the center circular boss of the sample stage 3 is reduced to above 0℃ by adjusting the semiconductor refrigerator 2, and the temperature is generally set to be between 1℃ and 10℃ in combination with the actual seabed environment temperature; then, the pressure vessel 9 is connected to an external high-pressure gas source through a gas inlet pipeline, the pressure vessel 9 and the sample stage 3 are tightly connected, the high-pressure gas source is opened to input high-pressure gas into the pressure vessel 9, such as single-component gas of methane, ethane, propane, xenon, carbon dioxide or double-component or multi-component mixed gas of methane-ethane, methane-propane, methane-ethane-propane, etc. The pressure in the pressure vessel 9 is determined according to the set temperature and the gas hydrate phase equilibrium condition, and can be adjusted to be between 0 and 20 MPa within the pressure bearing range of the pressure vessel 9; the gas hydrate sample is spontaneously formed under the low temperature and high pressure condition.

[0055] S2, adjusting the sample stage 3 to the required angle by the lifter 12.

[0056] According to the need of simulating the dip angle of the reservoir, the dip angle of the sample stage 3 and the gas hydrate sample thereon is adjusted by adjusting the height of the lifter 12, and is generally between 0° and 45°. There is no obvious shaking during the adjustment of the lifter 12, and the dip angle of the sample stage 3 can be accurately maintained to simulate the gas hydrate surface nanometer liquid film flow caused by the dip of the reservoir. After the sample stage 3 and the gas hydrate sample thereon are inclined to the required angle, the locking bolt 14 is tightened to keep the sample stage 3 stable to avoid shaking during the test.

[0057] S3. The autoclave 9 is disassembled and removed from the upper portion of the sample stage 3, and the probe 4 of the scanning probe microscope 6 is moved so that the probe 4 is close to the gas hydrate sample.

[0058] The scanning driver 5 moves downward at a preset speed, so that the probe 4 at the front end of the scanning driver 5 gradually approaches the gas hydrate sample.

[0059] S4. Record the process of probe 4 contacting the gas hydrate sample and passing through the nano-liquid film on the surface of the gas hydrate, and obtain the probe jumping distance in this process.

[0060] The probe jump distance can be directly recorded by the controller of the scanning probe microscope 6. As described in this embodiment, the scanning probe microscope 6 is a Bruker Edge scanning probe microscope 6. The controller of the scanning probe microscope 6 is turned on, the PeakForce Tapping mode is selected, and the process of the probe 4 contacting the gas hydrate sample and passing through the nano-liquid film on the gas hydrate surface is recorded, as shown in FIG. Figure 2 shown. Figure 2 The solid line in the middle represents the process of the probe 4 approaching, contacting, passing through the nano-liquid film on the surface of the gas hydrate, and applying a load. Figure 2 Process A represents the process in which the probe 4 gradually approaches the gas hydrate surface from a distance. If the distance between the probe 4 and the sample is relatively far, the interaction force between the two can be ignored and the probe 4 does not bend. When the probe 4 is very close to the gas hydrate sample surface, the gravitational gradient is greater than the elastic coefficient of the probe 4 under the action of attraction. The probe 4 will become unstable and pass through the relatively soft nano-liquid film on the gas hydrate surface, and finally adsorb to the solid gas hydrate surface. At this time, the needle tip is acted upon by the adsorption force, and the probe 4 bends downward, as shown in FIG. Figure 2 As shown in process B. Subsequently, the scanning driver 5 brings the probe 4 closer to the gas hydrate sample, the downward deflection of the probe 4 gradually decreases, and the resistance of the gas hydrate to the probe 4 increases. When the deflection decreases to zero, the probe 4 is almost naturally straightened, as shown in FIG. Figure 2 Process C is shown. Figure 2 L shown in BC This is the jump distance of probe 4.

[0061] S5. Performing a systematic error calibration on the probe jump distance recorded by the scanning probe microscope 6 to obtain the change of the thickness of the nano-liquid film on the surface of the gas hydrate over time.

[0062] Considering the van der Waals attraction between the probe 4 and the nano-liquid film on the surface of the gas hydrate, the probe 4 becomes unstable before it contacts the nano-liquid film. This instability generates a systematic error, affecting the measurement accuracy. Therefore, it is necessary to correct this systematic error. The systematic error Δd of the probe jump distance recorded by the scanning probe microscope 6 is calculated as follows:

[0063]

[0064] Where: H is the Hamaker constant of gas hydrate, usually taken as 1.39×10 -19 J. In order to better and more clearly illustrate the specific implementation method, a V-type probe 4 (model SCANASYST-FLUID) is used as an example. The probe 4 is only a preferred choice in the implementation of the present invention, and does not limit the implementation method of the present invention. Regardless of which probe 4 is used, the system error calibration described in the present invention falls within the protection scope of the present invention. The tip radius R of this model V-type probe 4 is 2nm, and the elastic coefficient k is 0.7N / m. Substituting it into the calculation formula of the system error Δd, the system error Δd is 0.51nm. The probe jump distance recorded in S4, that is, Figure 2 L in BC By subtracting the systematic error Δd from the segment, the exact thickness of the nano-liquid film on the gas hydrate surface can be obtained.

[0065] S6. Substituting the thickness of the nano-liquid film on the surface of the gas hydrate obtained at different times into the calculation formula, the fluidity of the nano-liquid film on the surface of the gas hydrate is obtained.

[0066] For example, with a test time interval of 5 minutes, the jump distances of the probe 4 recorded by the scanning probe microscope 6 within two hours are calibrated in step S5 to obtain 24 sets of gas hydrate surface nano-liquid film thicknesses.

[0067] The calculation formula for the fluidity of the nano-liquid film on the surface of gas hydrate is:

[0068]

[0069] Where: N represents the total number of nano-liquid film thickness data on the surface of gas hydrates. In this embodiment, N is 24. N represents the probe jump distance after calibration of the Nth group, for example, d1 represents the probe jump distance recorded by the scanning probe microscope 6 minus the systematic error Δd, and the first group of gas hydrate surface nano-liquid film thickness data after calibration; d2 represents the probe jump distance recorded by the scanning probe microscope 6 minus the systematic error Δd, and the second group of gas hydrate surface nano-liquid film thickness data after calibration; and so on, d 24 represents the probe jump distance recorded by the scanning probe microscope 6 minus the systematic error Δd, and the 24th group is obtained after calibration, that is, the 24th group of gas hydrate surface nano-liquid film thickness data; d aThis represents the average of all 24 sets of gas hydrate surface nanofilm thickness data after correction for the systematic error Δd. Substituting this into the formula yields a value representing the fluidity of the gas hydrate surface nanofilm (in %). This quantitative comparison value indicates that larger values ​​indicate more significant changes and greater fluidity of the gas hydrate surface nanofilm; smaller values ​​indicate less fluidity.

[0070] In this document, directional terms such as front, back, top, and bottom are defined based on the positions of components in the accompanying drawings and relative to each other, and are intended for clarity and convenience in describing the technical solution. It should be understood that these terms are relative and may vary depending on usage and placement. The use of these directional terms should not limit the scope of protection claimed in this application.

[0071] The above embodiments and features of the embodiments may be combined with each other unless they conflict. The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for testing the fluidity of a nano-liquid film on the surface of a gas hydrate, characterized by: The following steps are involved: S1. Add ultrapure water to the sample stage, adjust the temperature of the sample stage using a hot and cold stage, and inject organic gas at the required pressure into the sample stage through a pressure autoclave to prepare a gas hydrate sample. S2. Adjust the sample stage to the desired angle using the lifter; S3. dismantling the autoclave from the upper portion of the sample stage, and moving the probe of the scanning probe microscope so that the probe is close to the gas hydrate sample; S4, recording the process of the probe contacting the gas hydrate sample and passing through the nano-liquid film on the surface of the gas hydrate, and obtaining the probe jumping distance in this process; S5. Calibrate the systematic error of the probe jump distance recorded by the scanning probe microscope to obtain the change of the nano-liquid film thickness on the gas hydrate surface with time. Δ d The calculation formula is as follows: Where: H is the Hamaker constant for gas hydrates, R is the tip radius of the probe; K is the elastic modulus of the probe; S6. Substituting the thickness of the nano-liquid film on the surface of the gas hydrate obtained at different times into the calculation formula to obtain the fluidity of the nano-liquid film on the surface of the gas hydrate, wherein the calculation formula for the fluidity of the nano-liquid film on the surface of the gas hydrate is: Where: N Represents the total number of data on the thickness of the nano-liquid film on the surface of gas hydrates, d N Representative N probe jump distance after group calibration; d a Represents the average of the probe jump distances after calibration for all groups.

2. The method for testing the fluidity of a nano-liquid film on a gas hydrate surface according to claim 1, wherein: A test device for the fluidity of a nano-liquid film on a gas hydrate surface is used, the device comprising: glove box; a base, which is fixedly disposed in the glove box; A hot and cold stage, which is movably arranged on the base; A lifter connected to the hot and cold stages to drive the hot and cold stages to tilt to a desired angle; The sample stage is placed on the hot and cold stage, and the hot and cold stage is used to cool the sample stage to the required temperature. A pressure autoclave, which is arranged above the hot and cold stages and can be detachably connected to the sample stage, for applying a required air pressure to the sample stage; And a scanning probe microscope, the probe of the scanning probe microscope is used to contact the gas hydrate sample generated on the sample stage, obtain the probe jumping distance in the process of the probe contacting and passing through the nano-liquid film on the surface of the gas hydrate, and the change of the thickness of the nano-liquid film on the surface of the gas hydrate with time can be obtained from the probe jumping distance, so that the fluidity of the nano-liquid film on the surface of the gas hydrate can be obtained according to the thickness of the nano-liquid film on the surface of the gas hydrate obtained at different times.

3. The method for testing the fluidity of a nano-liquid film on a gas hydrate surface according to claim 2, wherein: A card plate is provided at the bottom of the hot and cold table, one end of the card plate is supported on the base, and the other end is provided with a bent plug plate. The lifter is arranged on the base and connected to the card plate. A U-shaped bolt seat is provided on one side of the base, and the plug plate can be movably inserted into the bolt seat. The bolt seat is provided with a locking bolt, and the locking bolt can lock the plug plate.

4. The method for testing the fluidity of a nano-liquid film on a gas hydrate surface according to claim 2, wherein: The scanning probe microscope further includes an optical microscope and a scanning driver for driving the probe to move.

5. The method for testing the fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 2, wherein: The hot and cold stages are provided with semiconductor refrigerators, and the sample stage is arranged on the semiconductor refrigerators.

6. The method for testing the fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 2, wherein: The glove box is a dehumidification glove box with a molecular sieve drying tank.

7. The method for testing the fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 2, wherein: The pressure autoclave is provided with a quick connector at the upper end and a flange at the lower end. The quick connector is used to connect to an external air source through an air inlet pipe, and the flange is connected to the sample stage.

8. The method for testing the fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 7, wherein: A sealing ring is provided between the flange and the sample stage.

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