Device and method for testing fluidity of nano liquid film on surface of gas hydrate

Abstract

The invention provides a device and a method for testing the flowability of a nano liquid film on the surface of a gas hydrate, and relates to the technical field of geological engineering. The base is fixedly arranged in the glove box; the cold and hot table is movably arranged on the base; the lifter is connected with the cold and hot table; the sample table is arranged on the cold and hot table; the pressure kettle can be detachably connected with the sample table; and the scanning probe microscope is used for obtaining the jumping distance of the probe in the process that the probe makes contact with and penetrates through the gas hydrate surface nanometer liquid film, the change of the thickness of the gas hydrate surface nanometer liquid film along with time can be obtained, and therefore the fluidity of the gas hydrate surface nanometer liquid film is obtained. The device and the method have the beneficial effects that the requirements of gas hydrate synthesis, stability and surface nano liquid film flowing are met, and accurate measurement and fluidity analysis of the thickness of the gas hydrate surface nano liquid film are realized.

Description

Technical Field

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

[0002] Gas hydrates are solid compounds with cage structures formed by water molecules and gas molecules such as methane and propane under high pressure and low temperature conditions. The most well-known of these is natural gas hydrate. Under the influence of continuous drilling and production activities, the crystals on the surface of gas hydrates will spontaneously decompose through phase change and produce a nano-thick amorphous transition liquid film. The nano-liquid film on the surface of the gas hydrate will flow under the influence of the reservoir inclination, directly affecting the contact, friction, adhesion and other interactions between gas hydrate particles and between gas hydrate and sediment particles. This is the key reason for the occurrence of adverse response behaviors such as degradation of wellbore stability, instability of gas hydrate-containing reservoirs, and formation subsidence during drilling and production, which restricts the efficient exploitation of gas hydrates and production safety.

[0003] In order to break through this engineering bottleneck, understanding the changes in the fluidity of the nano-liquid film on the surface of gas hydrates, especially the evolution characteristics of the fluidity and thickness of the nano-liquid film on the surface of gas hydrates when the reservoir is tilted and unstable, is the premise and basis for regulating the interaction behavior between gas hydrate particles, optimizing the safety risk prevention plan for drilling and production engineering, and promoting the safe development of gas hydrates. However, since maintaining the stability of gas hydrates requires low temperature and high pressure conditions, and the sample stage must be able to tilt freely to simulate the reservoir inclination, the existing scanning probe microscope cannot accurately measure the thickness of the nano-liquid film on the surface of gas hydrates, and it is even more impossible to quantitatively evaluate the fluidity of the nano-liquid film. Summary of the invention

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

[0005] 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, 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 stage to drive the hot and cold stage to tilt to a desired angle;

[0010] The sample stage is arranged 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 cooker, which is arranged above the hot and cold stage and can be detachably connected to the sample stage, and is used to apply a required gas 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, 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 also includes an optical microscope and a scanning driver for driving the probe to move.

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

[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 the surface of a gas hydrate, using the above-mentioned testing device for the fluidity of a nano-liquid film on the surface of a gas hydrate, 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, inputting gas of required pressure into the sample stage by the autoclave, and preparing a gas hydrate sample;

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

[0022] S3, disassembling and removing the autoclave from the upper portion of the sample platform, and moving the probe of the scanning probe microscope to bring the probe 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, performing a systematic error calibration on the probe jump distance recorded by the scanning probe microscope to obtain the change of the nano-liquid film thickness on the surface of the gas hydrate 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 data on the thickness of the nano-liquid film 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 after calibration.

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

[0033] 1. A testing device for the fluidity of nano-liquid film on the surface of gas hydrates of the present invention provides suitable temperature and pressure conditions in the sample stage through a hot and cold stage and a pressure autoclave to synthesize gas hydrates, and adjusts the inclination angle of the sample stage through a lifter to achieve the goal of simulating the flow of nano-liquid film on the surface of gas hydrates caused by reservoir inclination, while meeting the requirements of gas hydrate synthesis, stability and surface nano-liquid film flow, and can realize accurate measurement of the thickness of nano-liquid film on the surface of gas hydrates and fluidity analysis at the nanoscale.

[0034] 2. A method for testing the fluidity of nano-liquid films on the surface of gas hydrates of the present invention prepares gas hydrate samples through a testing device for the fluidity of nano-liquid films on the surface of gas hydrates and simulates the flow of nano-liquid films on the surface of gas hydrates caused by reservoir inclination. The thickness of 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 to achieve quantitative characterization of the fluidity of nano-liquid films on the surface of gas hydrates. This 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 It is a schematic diagram of a test device for fluidity of a nano-liquid film on the surface of a gas hydrate according to the present invention;

[0036] Figure 2 The 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 intake 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] In order to make the purpose, technical solution and advantages of the present invention clearer, the following will further describe the embodiments of the present invention in conjunction with the accompanying drawings. The following is a preferred embodiment of the present invention, which is intended to provide a basic understanding of the present invention, but is not intended to confirm 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 as 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, so 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 proportional relationship.

[0042] It should be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] Please refer to Figure 1 An embodiment of the present invention provides a testing device for 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 cooker 9 and a scanning probe microscope 6.

[0044] The glove box 17 is used to provide a dry and stable test environment. In this embodiment, the glove box 17 is a dehumidification glove box with a molecular sieve drying tank. The dehumidification glove box can drive the air in the glove box through the molecular sieve drying tank. The high-quality porous molecular sieve installed inside can absorb moisture in the air in the glove box 17, making the dew point of the air in the box less than -70°C, and preventing moisture from condensing on the surface of the gas hydrate.

[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 table 3 is arranged on the hot and cold table 1, and the hot and cold table 1 is used to cool the sample table 3 to a desired temperature. Here, a semiconductor refrigerator 2 is arranged on the hot and cold table 1, and the sample table 3 is arranged on the semiconductor refrigerator 2. The center of the sample table 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, and the temperature control range is -60℃ to 40℃, and the temperature control accuracy is ±0.01℃, which 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 table 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 a desired angle. Specifically, a cardboard 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 cardboard 18 by screws 8. One end of the cardboard 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 cardboard 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] In this way, when the locking bolt 14 is loosened, the lifter 12 can drive the clamping plate 18 to move up and down to drive the hot and cold table 1 to move up and down, thereby adjusting the hot and cold table 1 to a desired angle, and the hot and cold table 1 can be tilted from 0° to 45°. After that, tightening the locking bolt 14 can keep the hot and cold table 1 stable.

[0048] The pressure cooker 9 is disposed above the hot and cold stage 1 and can be detachably connected to the sample stage 3 to apply the required air pressure to the sample stage 3. Specifically, the pressure cooker 9 is a hollow cylindrical cavity, 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 10, and the flange is connected to the sample stage 3.

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

[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 of the process in which the probe 4 contacts and passes 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 also includes an optical microscope 7 and a scanning driver 5 for driving the probe 4. The optical microscope 7 is arranged above the sample stage 3, and the magnification can be up to 50 times. The probe 4 is installed at the front end of the scanning driver 5, and the scanning driver 5 can drive the probe 4 to move according to a pre-set motion trajectory. In addition, the scanning driver 5 can install and remove probes 4 of different models.

[0052] In addition, an embodiment of the present invention further provides a method for testing the fluidity of a nano-liquid film on the surface of a gas hydrate, using the above-mentioned testing device for the fluidity of a nano-liquid film on the surface of a gas hydrate, and further comprising the following steps:

[0053] S1. Ultrapure water is dripped onto the sample stage 3, the temperature of the sample stage 3 is adjusted by the hot and cold stage 1, and gas of required pressure is input into the sample stage 3 by the pressure autoclave 9 to prepare a gas hydrate sample.

[0054] Specifically: wipe the circular boss at the center of the sample stage 3 with dust-free paper, and drop two drops of ultrapure water on it, about 30 microliters; adjust the semiconductor refrigerator 2 to reduce the temperature of the circular boss at the center of the sample stage 3 to above 0°C, and combine the actual seabed environment temperature, usually set to between 1°C and 10°C; then, connect the pressure autoclave 9 to an external high-pressure gas source through an air inlet pipeline, and tightly connect the pressure autoclave 9 and the sample stage 3, open the high-pressure gas source to pass high-pressure gas into the pressure autoclave 9, such as methane, ethane, propane, xenon, carbon dioxide and other single-component gases or methane-ethane mixture, methane-propane mixture, methane-ethane-propane mixture and other two-component or multi-component mixed gases. The pressure in the pressure autoclave 9 is determined according to the set temperature and the gas hydrate phase equilibrium condition, and can be adjusted within the pressure range of the pressure autoclave 9 from 0 to 20MPa; gas hydrate samples will spontaneously form under this low temperature and high pressure condition.

[0055] S2. The sample stage 3 is adjusted to a desired inclination angle by the lifter 12.

[0056] According to the need of simulating the inclination of the reservoir, the inclination angle of the sample stage 3 and the gas hydrate sample thereon is adjusted by adjusting the height of the lifter 12, which is generally between 0° and 45°. There is no obvious shaking during the adjustment of the lifter 12, and the inclination angle of the sample stage 3 can be accurately maintained to simulate the flow of nano-liquid film on the surface of the gas hydrate caused by the inclination of the reservoir. After the sample stage 3 and the gas hydrate sample thereon are tilted to the desired 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 part 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 in which the probe 4 contacts the gas hydrate sample and passes 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 surface of the gas hydrate is recorded, such as 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 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 surface of the gas hydrate sample, the gravitational gradient is greater than the elastic coefficient of the probe 4 under the action of attraction, and the probe 4 will become unstable and pass through the softer gas hydrate surface nano-liquid film, 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 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 As shown in L 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 with time.

[0062] Considering the Van der Waals mutual attraction between the probe 4 and the nano-liquid film on the surface of the gas hydrate, the probe 4 becomes unstable before contacting the nano-liquid film on the surface of the gas hydrate. This instability phenomenon produces a systematic error, which affects the measurement accuracy. Therefore, it is necessary to correct the systematic error. The calculation formula for the systematic error Δd of the probe jump distance recorded by the scanning probe microscope 6 is as follows:

[0063]

[0064] Where: H is the Hamaker constant of gas hydrate, usually 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 for explanation. 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 the type of probe 4 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 of V-type probe 4 is 2nm, and the elastic coefficient k is 0.7N / m. Substituting into the calculation formula of the system error Δd, the system error Δd is obtained to be 0.51nm. The probe jump distance recorded in S4, that is Figure 2 L BC By subtracting the systematic error Δd from the segment, the exact thickness of the nano-liquid film on the surface of the gas hydrate 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 jumping 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 of the fluidity of the nano-liquid film on the surface of gas hydrate is:

[0068]

[0069] Where: N represents the total number of data on the thickness of the nano-liquid film on the surface of the gas hydrate. In this embodiment, N is 24. N represents the probe jump distance after calibration of the Nth group, such as 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, i.e., the 24th group of gas hydrate surface nano-liquid film thickness data, is obtained after calibration; d aRepresents the average value of all 24 sets of gas hydrate surface nano-liquid film thickness data after calibration of the system error Δd. Substituting into the formula, the value representing the fluidity of the gas hydrate surface nano-liquid film can be obtained, in %. Quantitative comparison value, the larger the value, the more significant the change of the gas hydrate surface nano-liquid film, the stronger the fluidity; the smaller the value, the worse the fluidity of the gas hydrate surface nano-liquid film.

[0070] In this article, the directional words such as front, back, top, and bottom involved are defined by the positions of the parts in the drawings and the positions of the parts relative to each other, just for the sake of clarity and convenience in expressing the technical solution. It should be understood that they are relative concepts and can change accordingly according to different ways of use and placement, and the use of the directional words should not limit the scope of protection claimed in this application.

[0071] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A test device for the fluidity of a nano-liquid film on the surface of a gas hydrate, characterized in that: include: 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 stage to drive the hot and cold stage to tilt to a desired angle; The sample stage is arranged 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 cooker, which is arranged above the hot and cold stage and can be detachably connected to the sample stage, and is used to apply a required gas 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.

2. A test device for the fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 1, characterized in that: 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, 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.

3. A test device for the fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 1, characterized in that: The scanning probe microscope also includes an optical microscope and a scanning driver for driving the probe to move.

4. A test device for the fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 1, characterized in that: The hot and cold stage is provided with a semiconductor refrigerator, and the sample stage is arranged on the semiconductor refrigerator.

5. A test device for the fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 1, characterized in that: The glove box is a dehumidified glove box with a molecular sieve drying tank.

6. A test device for fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 1, characterized in that: 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.

7. A device for testing the fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 6, characterized in that: A sealing ring is arranged between the flange and the sample stage.

8. A method for testing the fluidity of a nano-liquid film on the surface of a gas hydrate, characterized in that: A test device for the fluidity of a nano-liquid film on the surface of a gas hydrate as claimed in any one of claims 1 to 7 is used, and further comprising the following steps: S1, dripping ultrapure water onto the sample stage, adjusting the temperature of the sample stage by the hot and cold stage, inputting gas of required pressure into the sample stage by the autoclave, and preparing a gas hydrate sample; S2, adjusting the tilt of the sample stage to a desired angle by means of the lifter; S3, disassembling and removing the autoclave from the upper portion of the sample platform, and moving the probe of the scanning probe microscope to bring the probe 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, performing a systematic error calibration on the probe jump distance recorded by the scanning probe microscope to obtain the change of the nano-liquid film thickness on the surface of the gas hydrate with time; 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.

9. A method for testing the fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 8, characterized in that: The formula for calculating the systematic error Δd of the probe jump distance recorded by the scanning probe microscope in step S5 is as follows: 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.

10. A method for testing the fluidity of a nano-liquid film on the surface of a gas hydrate according to claim 8, characterized in that: The calculation formula for the fluidity of the nano-liquid film on the surface of the gas hydrate in step S6 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 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 after calibration.

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