Gas hydrate gas content measurement apparatus and method

Abstract

This invention provides a device and method for measuring the gas hydrate content. The device includes a sample container, a calibration container, a vacuum pump, a cooling device, a temperature sensor, and a vacuum gauge. The sample container, calibration container, and vacuum pump are connected to the same connecting pipe via different valves. The sample container, calibration container, and connecting pipe form a closed system. The temperature sensor and vacuum gauge are used to detect the temperature and pressure of the gas within the connecting pipe, respectively. The cooling device is used to regulate the temperature inside the sample container. Compared with existing technologies, this measuring device has a simple structure, low manufacturing cost, and is easy to promote. When using this device to measure gas hydrates, the operation process is simple, and the measurement results are not easily affected by the environment and experimental operations. It is suitable not only for on-site measurement of natural gas hydrates in exploration and extraction, and for measuring the gas hydrate content in sediment samples obtained from drilling, but also for measuring the gas hydrate content in laboratory synthetic gas hydrates.

Description

Technical Field

[0001] This invention relates to the technical field of gas hydrate detection devices, and more particularly to a gas hydrate content measurement device and method. Background Technology

[0002] Gas hydrate content is defined as the amount of gas produced by the decomposition of a unit mass of hydrate sample, and it is a key parameter for evaluating the potential reserves of hydrate resources. In the exploration and development of natural gas hydrates, gas hydrate content is an important parameter for evaluating hydrate gas storage capacity, hydrate reservoir quality, and estimating the amount of natural gas hydrate resources.

[0003] Currently, the gas content of gas hydrates is mainly measured by laboratory instruments. The main methods for measuring the gas content of gas hydrates are the weighing method and the instrumental method.

[0004] The gravimetric method calculates the mass of a gas by measuring the weight loss of a gas hydrate sample before and after decomposition under standard conditions using a balance. However, this method is affected by the gas composition and requires the use of gas chromatography or other methods to estimate the average molecular weight of the gas. Furthermore, this method is greatly affected by the environment and experimental procedures.

[0005] Instrumental methods primarily employ Raman spectroscopy, nuclear magnetic resonance (NMR), and X-ray diffraction. However, the theoretical models used for quantitative calculations of gas hydrate content in instrumental methods rely on numerous assumptions, and their accuracy requires further verification. Furthermore, the measurement and data processing procedures are cumbersome and costly. Additionally, instrumental methods are only suitable for measuring pure gas hydrate samples, posing challenges for determining natural gas hydrates distributed within sediment pores. In November 2015, Fu Juan et al. published an experimental procedure for measuring hydrate samples using Raman spectroscopy in *Spectroscopy and Spectral Analysis*, introducing a method for calculating parameters such as cage occupancy and gas content using relatively quantitative methods. However, this method is difficult to measure natural hydrate samples distributed within sediment pores and requires specialized laser Raman spectrometers and associated temperature control equipment for hydrate measurement. The experimental procedure is cumbersome, the analytical methods are complex, and the measurement costs are high, making it unsuitable for on-site measurements at hydrate mining sites and limiting its widespread application.

[0006] Therefore, there is currently no suitable device or method for measuring the gas content of gas hydrates at hydrate exploration and mining sites. Summary of the Invention

[0007] To address the lack of simple devices and methods suitable for determining the gas content in gas hydrate exploration and extraction sites, this invention provides a gas hydrate gas content measurement device and method based on the vacuum volumetric method. The gas hydrate gas content is calculated using the temperature and pressure values ​​of the gas produced by the decomposition of gas hydrates under vacuum conditions. The main principle of this invention for determining the amount of gas produced by gas hydrate decomposition is as follows:

[0008] Assume there exists an independent, first closed system with an unknown volume, denoted by V. The initial pressure of the first closed system is P0, and the temperature is maintained at T. A gas hydrate sample is placed in the first closed system. As the cooling liquid nitrogen is depleted, the gas hydrate sample begins to decompose. After complete decomposition, the pressure of the first closed system remains constant at P1. At this point, since the volume of the first closed system is unknown, the amount of gas hydrate decomposition gas cannot be calculated. If a calibration container with a known volume of V0 exists and is connected to the first closed system, with an initial pressure of P0, the valve between the calibration container and the first closed system is opened, connecting the calibration container and the first closed system to form a second closed system. The decomposition gas diffuses into the calibration container, and the pressure of the second system stabilizes at a lower value, P2. The amount of gas hydrate decomposition gas can then be calculated based on the pressure change of the system.

[0009] (P1-P0)×V=nRT

[0010] (P2-P0)×(V+V0)=nRT

[0011] Where n is the amount of gas produced after the complete decomposition of the gas hydrate.

[0012] Therefore, (P1-P0)×V=(P2-P0)×(V+V0)

[0013]

[0014] Finally, the amount of decomposition gas from natural gas hydrate can be calculated.

[0015]

[0016] Based on the above principle, the present invention provides a gas hydrate content measuring device, which can realize the purpose of measuring the gas hydrate content at the hydrate exploration and mining site.

[0017] The present invention provides a gas hydrate content measuring device, comprising a sample container, a calibration container, a vacuum pump, a cooling device, a temperature sensor, and a vacuum gauge; the sample container, the calibration container, and the vacuum pump are respectively connected to the same connecting pipe; the sample container, the calibration container, and the connecting pipe form a closed system, and the vacuum pump is used to discharge the gas within the closed system; a first valve is provided between the sample container and the connecting pipe, a second valve is provided between the calibration container and the connecting pipe, and a third valve is provided between the vacuum pump and the connecting pipe; the temperature sensor and the vacuum gauge are disposed on the connecting pipe and are respectively used to detect the temperature and pressure of the gas within the connecting pipe; the cooling device is used to regulate the temperature within the sample container.

[0018] Preferably, the cooling device is a cooling pool containing liquid nitrogen.

[0019] Preferably, it also includes one or more spare sample containers.

[0020] Preferably, the system further includes a data processing system, which comprises a data acquisition module, a digital display screen, and a data processing module. The data acquisition module is connected to the temperature sensor and the vacuum gauge respectively and transmits the acquired temperature and pressure data to the data processing module. The data processing module calculates the amount of gas hydrate decomposition gas based on the temperature and pressure data and transmits the calculation result to the digital display screen for display.

[0021] Preferably, the system also includes a housing, within which the sample container, the calibration container, the vacuum pump, the cooling device, the temperature sensor, and the vacuum gauge are all housed.

[0022] Preferably, a handle and a power socket are provided on the outer side of the housing.

[0023] The present invention also provides a method for measuring the gas hydrate content, which uses the above-mentioned gas hydrate content measuring device and includes the following steps:

[0024] A sample container containing a gas hydrate sample is connected to a connecting pipe, and the temperature inside the sample container is controlled by a cooling device to keep the temperature below the decomposition temperature of the gas hydrate sample.

[0025] Turn on the vacuum gauge and the temperature sensor; while keeping the first valve, the second valve and the third valve open, turn on the vacuum pump to extract the gas in the closed system; when the pressure in the closed system no longer changes, close the third valve and record the pressure P0.

[0026] Keep the first valve open, close the second and third valves, and control the temperature inside the sample container through the cooling device to make the temperature higher than the decomposition temperature of the gas hydrate sample. The gas hydrate sample decomposes, and the pressure in the sample container and connecting pipe rises. When the temperature and pressure in the sample container and connecting pipe no longer change, record the temperature T and pressure P1 at this time.

[0027] Open the second valve to allow the gas hydrate decomposition gas portion to enter the calibration container. Record the pressure P2 after the pressure stabilizes.

[0028] The amount of decomposition gas from gaseous hydrates can be calculated using the following formula:

[0029]

[0030] P0 - The pressure of residual air in the sample container, connecting pipe, and calibration container after vacuum extraction; P1 - The gas pressure filling the sample container and connecting pipe after complete decomposition of gas hydrates.

[0031] After the complete decomposition of P2- gas hydrates, the gas pressure in the sample container, connecting tubing, and calibrator is...

[0032] V0 - Volume of the calibration container;

[0033] The gas content of gas hydrates is ε = n / m, where m is the mass of the gas hydrate sample.

[0034] Preferably, the mass m of the gas hydrate sample can be measured by the following steps:

[0035] Weigh the clean and dry sample container using a balance;

[0036] The sample container is placed in a liquid nitrogen bath and cooled to liquid nitrogen temperature. The gas hydrate sample is placed in the sample container, and the total mass m1 of the sample container and the gas hydrate sample is weighed using a balance. The mass of the gas hydrate sample is m = m1 - m0.

[0037] Preferably, after the measuring device is assembled, the airtightness of the measuring device is checked by the following steps:

[0038] With the first valve, the second valve, and the third valve all open, turn on the vacuum pump to extract the gas from the sealed system; once the pressure in the sealed system stops changing, close the third valve and turn off the vacuum pump; let the measuring device stand for a predetermined time. If the pressure in the sealed system does not change within the predetermined time, it indicates that the measuring device is well sealed.

[0039] Preferably, P0 is less than 100 Pa.

[0040] Compared with existing technologies, the gas hydrate content measuring device provided by this invention has a simple structure, low manufacturing cost, and is conducive to widespread application. Furthermore, the operation process is simple when using this device to measure gas hydrates, and the measurement results are not easily affected by the environment or experimental procedures. The built-in data processing system can directly process and obtain the amount of gaseous gases from the decomposition of gas hydrates, reducing tedious calculations. The standardized measuring elements are packaged in a portable carrying case, resulting in a simple structure, simplified measurement process, and easy on-site deployment. The preferred use of a high-precision vacuum gauge and thermocouple temperature sensors effectively improves the accuracy of measuring the temperature and pressure of the decomposition gas from gas hydrates, ensuring the accuracy of gas hydrate content calculations, and making it suitable for measuring small-dose gas hydrate samples.

[0041] The gas hydrate content measurement device and method provided by this invention are not only applicable to on-site measurement of natural gas hydrate exploration and mining, and to measuring the gas content of natural gas hydrate samples in sediments obtained from drilling, but can also be used to measure the gas content of artificially synthesized gas hydrates in the laboratory.

[0042] The above-mentioned technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved. Attached Figure Description

[0043] The invention will now be described in more detail based on embodiments that are merely non-limiting and with reference to the accompanying drawings. Wherein:

[0044] Figure 1 This is a schematic diagram of the structure of a gas hydrate content measuring device provided in an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of the structure of a gas hydrate content measuring device provided in another embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram of the structure of a gas hydrate content measuring device provided in another embodiment of the present invention.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1. Temperature sensor; 2. Connecting pipe; 3. Vacuum gauge; 4. Signal transmission line; 5. Sample container; 6. Cooling pool; 7. Spare sample container; 8. Sample container storage box; 9. Data processing system; 10. Vacuum hose; 12. Calibration container; 13. Vacuum pump; 14. Outer shell; 15. Handle; K1, First valve; K2, Second valve; K3, Third valve. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Based on the specific embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0050] The terms "first," "second," and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "above," "below," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, this relative positional relationship may also change accordingly.

[0051] In this disclosure, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may be not directly connected to the other devices but have an intermediary device.

[0052] Example 1:

[0053] like Figure 1 As shown, the gas hydrate content measuring device includes a sample container 5, a calibration container 12, a vacuum pump 13, a cooling device, a connecting pipe 2, a temperature sensor 1, and a vacuum gauge 3. In this embodiment, the connecting pipe 2 is preferably a stainless steel pipe, as stainless steel pipes are not easily damaged and are suitable for use at hydrate exploration and mining sites.

[0054] Sample container 5 is used to contain gas hydrate samples. Sample container 5 can be detachably connected to connecting pipe 2 via a vacuum reducer. A first valve K1 is provided between the vacuum reducer and connecting pipe 2 to control the opening and closing of the connection channel between sample container 5 and connecting pipe 2. The first valve K1 can be a vacuum ball valve.

[0055] The calibration container 12 has a cavity for containing gas. The calibration container 12 can be connected to the connecting pipe 2 via a vacuum reducer. A second valve K2 is installed between the vacuum reducer and the connecting pipe 2, controlling the opening and closing of the connection between the calibration container 12 and the connecting pipe 2. The second valve K2 can be a vacuum ball valve. After the calibration container 12 is manufactured, its volume should be measured to obtain its accurate volume.

[0056] The sample container 5, the calibration container 12, and the connecting pipe 2 form a closed system.

[0057] Vacuum pump 13 is used to expel gas from the closed system formed by sample container 5, calibration container 12, and connecting pipe 2, thereby reducing errors caused by gas in the closed system. The inlet of vacuum pump 13 is connected to connecting pipe 2 via vacuum hose 10. A third valve K3 is installed between vacuum pump 13 and connecting pipe 2, controlling the opening and closing of the connection between the vacuum pump 13 and connecting pipe 2. The third valve K3 can be a vacuum ball valve. In some preferred embodiments, vacuum pump 13 is a miniature dry pump or a rotary vane vacuum pump 13. To ensure instrument measurement accuracy, the ultimate vacuum of vacuum pump 13 is preferably less than 0.1 mbar (10 Pa).

[0058] Temperature sensor 1 is installed on connecting pipe 2 and is used to detect the temperature of the gas inside connecting pipe 2. In some preferred embodiments, temperature sensor 1 is a digital display temperature sensor, using a PT100 thermistor with an accuracy of ±0.1℃.

[0059] Vacuum gauge 3 is also installed on connecting pipe 2. Vacuum gauge 3 is used to detect the pressure of gas in connecting pipe 2. In some preferred embodiments, vacuum gauge 3 is a digital display vacuum gauge. More preferably, a capacitor diaphragm vacuum gauge is used. The range meets the standard atmospheric pressure of 0.1 Pa and the measurement accuracy needs to be better than ±5% of the reading.

[0060] By selecting a high-precision vacuum gauge 1 and a thermocouple temperature sensor 1, the accuracy of measuring the temperature and pressure of gas hydrate decomposition gas is effectively improved, ensuring the accuracy of gas hydrate content calculation and making it suitable for measuring small-dose gas hydrate samples.

[0061] The cooling device is used to regulate the temperature inside the sample container 5. By regulating the temperature inside the sample container 5, the temperature of the gas hydrate placed inside the sample container 5 is kept below or above its decomposition temperature, thereby controlling whether the gas hydrate decomposes or not. The cooling device is preferably a cooling pool 6, which is filled with liquid nitrogen. Moving the cooling pool 6 filled with liquid nitrogen to the bottom of the sample container 5, immersing the bottom of the sample container 5 in liquid nitrogen, lowers the temperature inside the sample container 5 below the decomposition temperature of the gas hydrate, thus preventing the gas hydrate inside the sample container 5 from decomposing. When the cooling pool 6 is removed from the bottom of the sample container 5, the temperature inside the sample container 5 gradually rises. When the temperature rises above the decomposition temperature of the gas hydrate, the gas hydrate inside the sample container 5 begins to decompose.

[0062] Example 2:

[0063] Based on the gas hydrate content measuring device provided in Example 1, a data processing system 9 is added (see...). Figure 2The data processing system 9 includes a data acquisition module, a digital display screen, and a data processing module. The data acquisition module is connected to the temperature sensor 1 and the vacuum gauge 3, respectively. The data acquisition module transmits the acquired temperature and pressure data to the data processing module. The data processing module calculates the amount of hydrate decomposition gas based on the temperature and pressure data and transmits the calculation results to the digital display screen for display. Specifically, the data processing module includes a storage and calculation processing chip and acquisition and processing software. The acquisition and processing software uses VB programming and can directly convert the measured parameter output into the amount of gaseous hydrate decomposition gas. By setting up the data processing system 9, the amount of gaseous hydrate decomposition gas can be directly obtained, reducing tedious calculation work.

[0064] Example 3:

[0065] Based on the gas hydrate content measuring device provided in Example 2, a portable carrying case shell 14 is added, such as... Figure 3 As shown, the sample container 5, connecting pipe 2, calibration container 12, vacuum pump 13, cooling tank 6, temperature sensor 1, vacuum gauge 3, and data processing system 9 are all enclosed inside the outer casing 14, along with the power supply lines required for the measuring device. Preferably, the outer casing includes a hinged cover and a box. The sample container 5, connecting pipe 2, and calibration container 12 are enclosed in the cover, while the vacuum pump 13 and data processing system 9 are enclosed in the box. This arrangement allows for full utilization of the space within the outer casing 14. When the outer casing 14 is opened, the sample container 5, connecting pipe 2, and calibration container 12 can be arranged vertically, facilitating the conduct of experiments. For portability, the outer casing 14 is designed as a carrying case 4, with a handle 15 and a socket assembly (not shown) on its side to meet the power requirements of the equipment.

[0066] In addition, the sample container 5 needs to be cleaned after use before it can be reused. To improve measurement efficiency, a sample container storage box 8 can be sealed inside the outer shell 14. The sample container storage box 8 contains several spare sample containers 7. After a measurement is completed, the spare sample container 7 can be directly replaced without waiting for the original sample container 5 to be cleaned, which is convenient for use at hydrate exploration and mining sites.

[0067] Example 4:

[0068] This invention also provides a method for measuring the gas content of gas hydrates. This method is based on the vacuum volumetric method, which calculates the gas content of gas hydrates by utilizing the temperature and pressure values ​​of the gas produced by the decomposition of gas hydrates under vacuum conditions. The following describes the operational steps of the method for measuring the gas content of gas hydrates using the gas hydrate content measuring device provided in Example 1:

[0069] (1) Check the airtightness of the device

[0070] When the measuring device follows Figure 1 After assembly, with the first valve K1, the second valve K2, and the third valve K3 kept open, turn on the vacuum pump 13 to extract the gas in the closed system formed by the sample container 5, the calibration container 12, and the connecting pipe 2; when the pressure in the closed system no longer changes, close the third valve K3 and turn off the vacuum pump 13; let the measuring device stand for 24 hours. If the pressure in the closed system does not change within 24 hours, it indicates that the measuring device is well sealed.

[0071] (2) Calibration device

[0072] During the manufacturing process of the measuring device, the volume V0 of the calibrator must be accurately calibrated;

[0073] (3) Measuring the mass of hydrate samples

[0074] First, weigh the clean and dry sample container 5 using a balance; then, place the sample container 5 in a liquid nitrogen bath to cool it to liquid nitrogen temperature, place the gas hydrate sample in the sample container 5, and weigh the total mass m1 of the sample container 5 and the gas hydrate sample using a balance; the mass of the gas hydrate sample is m = m1 - m0; note that this weighing step needs to be performed quickly to avoid errors in the calculation of the gas hydrate mass caused by the sublimation of water vapor in the air.

[0075] (4) Measurement of gaseous hydrate decomposition gas:

[0076] The cooling device can be a cooling pool 6, which is filled with liquid nitrogen. The bottom of the sample container 5 containing the gas hydrate sample is immersed in the cooling pool 6 to make it in the liquid nitrogen environment, so that the temperature of the gas hydrate sample is lower than its decomposition temperature, and the gas hydrate does not decompose. Then the sample container 5 is connected to the connecting pipe 2.

[0077] Turn on vacuum gauge 3 and temperature sensor 1; while keeping the second valve K2 and the third valve K3 normally open, slightly open the first valve K1 and turn on vacuum pump 13 to extract the gas in the closed system. After the system pressure drops significantly, fully open the first valve K1 until the pressure in the closed system no longer changes. Then close the third valve K3 and record the pressure P0.

[0078] Keep the first valve K1 open, close the second valve K2 and the third valve K3, remove the cooling pool 6 at the bottom of the sample container 5, and the temperature inside the sample container 5 will gradually rise. When the temperature of the gas hydrate sample is higher than the decomposition temperature, the gas hydrate will decompose, and the pressure in the sample container 5 and the connecting pipe 2 will rise again. When the temperature and pressure in the sample container 5 and the connecting pipe 2 no longer change, it indicates that the gas hydrate sample has completely decomposed. Record the temperature T and pressure P1 at this time.

[0079] Open the second valve K2 to allow the gas hydrate decomposition gas portion to enter the calibration container 12. Record the pressure P2 after the pressure stabilizes.

[0080] (5) Calculate the gas content of natural gas hydrates. The main principles of the calculation are as follows:

[0081] The measuring device consists of three connected parts: sample container 5, connecting pipe 2, and calibration container 12, forming a closed system. The volumes V1 of sample container 5 and V2 of connecting pipe 2 are difficult to determine accurately. During the measurement of the gas hydrate decomposition gas, three pressure values, P0, P1, and P2, were recorded. P0 corresponds to the pressure of the residual air in the sample container 5, connecting pipe 2, and calibration container 12 after vacuuming. P1 corresponds to the gas pressure filling the sample container 5 and connecting pipe 2 after complete gas hydrate decomposition. P2 corresponds to the gas pressure filling the sample container 5, connecting pipe 2, and calibration container 12 after complete gas hydrate decomposition. These pressures can be obtained from the gas law.

[0082] (V1+V2)×(P1-P0)=nRT

[0083] (V1+V2+V0)×(P2-P0)=nRT

[0084] Where n is the amount of gas produced after the complete decomposition of the gas hydrate.

[0085] Therefore, (V1+V2)×(P1-P0)=(V1+V2+V0)×(P2-P0)

[0086]

[0087]

[0088] P0 - The pressure of residual air in the sample container 5, connecting pipe 2, and calibration container 12 after vacuum extraction.

[0089] After the complete decomposition of P1-gas hydrate, the gas pressure in both the sample container 5 and the connecting pipe 2 is...

[0090] After the complete decomposition of P2- gas hydrate, the gas pressure in the sample container 5, connecting pipe 2, and calibrator is maintained.

[0091] V0 - Volume of calibration container 12;

[0092] The gas content of gas hydrates is ε = n / m, where m is the mass of the gas hydrate sample.

[0093] Therefore, the volume of the decomposition gas per unit mass of the gas hydrate sample under standard conditions can be calculated to be 22.4ε liters.

[0094] Checking the airtightness of the apparatus is not a necessary step for every measurement of gas hydrate decomposition gas. It is usually required to re-check the airtightness after the apparatus is assembled or after replacing consumables such as vacuum hoses 10 and valves.

[0095] Once the volume of the calibration container 12 in the measuring device is calibrated, it does not need to be recalibrated unless the original calibration container 12 is damaged or replaced.

[0096] In the measurement of gas hydrate decomposition gas, when the closed system is evacuated, the smaller the P0, the more beneficial it is to reduce the error caused by the gas in the closed system. Preferably, P0 is less than 100 Pa.

[0097] Throughout the measurement process of the gas hydrate decomposition gas, the temperature inside the connecting pipe 2 is approximately the same as the temperature of the environment in which the measuring device is located, i.e., approximately constant temperature.

[0098] During the vacuuming process, the first valve K1 is slightly opened for a period of time before being fully opened, which can reduce the decomposition of gas hydrates during the vacuuming process.

[0099] Finally, it should be noted that the above embodiments and examples are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments and examples, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments or examples, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments or examples of the present invention.

Claims

1. A method for measuring the gas content of gas hydrates, characterized in that, The gas hydrate content is measured using a gas hydrate content measuring device, which includes a sample container, a calibration container, a vacuum pump, a cooling device, a temperature sensor, and a vacuum gauge. The sample container, calibration container, and vacuum pump are all connected to the same connecting pipe. The sample container, calibration container, and connecting pipe form a closed system. The vacuum pump is used to expel the gas within the closed system. A first valve is installed between the sample container and the connecting pipe, a second valve is installed between the calibration container and the connecting pipe, and a third valve is installed between the vacuum pump and the connecting pipe. The temperature sensor and the vacuum gauge are installed on the connecting pipe and are used to detect the temperature and pressure of the gas within the connecting pipe, respectively. The cooling device is used to regulate the temperature inside the sample container. The measurement method includes the following steps: A sample container containing a gas hydrate sample is connected to a connecting pipe, and the temperature inside the sample container is controlled by a cooling device to keep the temperature below the decomposition temperature of the gas hydrate sample. Turn on the vacuum gauge and the temperature sensor; while keeping the first valve, the second valve and the third valve open, turn on the vacuum pump to extract the gas in the closed system; when the pressure in the closed system no longer changes, close the third valve and record the pressure P0. Keep the first valve open, close the second and third valves, and control the temperature inside the sample container through the cooling device to make the temperature higher than the decomposition temperature of the gas hydrate sample. The gas hydrate sample decomposes, and the pressure in the sample container and connecting pipe rises. When the temperature and pressure in the sample container and connecting pipe no longer change, record the temperature T and pressure P1 at this time. Open the second valve to allow the gas hydrate decomposition gas portion to enter the calibration container. Record the pressure P2 after the pressure stabilizes. The amount of decomposition gas from gaseous hydrates can be calculated using the following formula: P0 - The pressure of residual air in the sample container, connecting pipes, and calibration container after vacuum extraction. The gas pressure in the sample container and connecting pipe after complete decomposition of P1- gas hydrate After the complete decomposition of P2- gas hydrate, the gas pressure in the sample container, connecting pipes, and calibration container is as follows: V0 - Volume of the calibration container; Gas content of gas hydrates , where m is the mass of the gas hydrate sample.

2. The method for measuring the gas content of gas hydrates according to claim 1, characterized in that, The cooling device is a cooling pool, which contains liquid nitrogen.

3. The method for measuring the gas content of gas hydrates according to claim 1, characterized in that, The gas hydrate content measuring device also includes one or more spare sample containers.

4. The method for measuring the gas content of gas hydrates according to claim 1, characterized in that, The gas hydrate content measuring device further includes a data processing system, which includes a data acquisition module, a digital display screen, and a data processing module. The data acquisition module is connected to the temperature sensor and the vacuum gauge respectively and transmits the acquired temperature and pressure data to the data processing module. The data processing module calculates the amount of gas decomposition gas of gas hydrate based on the temperature and pressure data and transmits the calculation result to the digital display screen for display.

5. The method for measuring the gas content of gas hydrates according to any one of claims 1-4, characterized in that, The gas hydrate content measuring device also includes a housing, and the sample container, the calibration container, the vacuum pump, the cooling device, the temperature sensor and the vacuum gauge are all disposed inside the housing.

6. The method for measuring the gas content of gas hydrates according to claim 5, characterized in that, A handle and a power socket are provided on the outer side of the housing.

7. The method for measuring the gas content of gas hydrates according to claim 1, characterized in that, The mass m of the gas hydrate sample can be measured by the following steps: Weigh the clean and dry sample container using a balance; The sample container is placed in a liquid nitrogen bath and cooled to liquid nitrogen temperature. The gas hydrate sample is placed in the sample container, and the total mass m1 of the sample container and the gas hydrate sample is weighed using a balance. The mass of the gas hydrate sample is m = m1 - m0.

8. The method for measuring the gas content of gas hydrates according to claim 1, characterized in that, After the measuring device is assembled, the airtightness of the measuring device is checked by the following steps: With the first valve, the second valve, and the third valve all open, turn on the vacuum pump to extract the gas from the sealed system; once the pressure in the sealed system no longer changes, close the third valve and turn off the vacuum pump; let the measuring device stand for a predetermined time. If the pressure in the sealed system does not change within the predetermined time, it indicates that the measuring device is well sealed.

9. The method for measuring the gas content of gas hydrates according to claim 1, characterized in that, The P0 is less than 100 Pa.

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