Full-diameter core gas content measuring device and measuring method

Abstract

The application provides a full-diameter core gas content measuring device and a measuring method. The measuring device comprises a gas pressurizing system, a liquid nitrogen freezing system, a vibration crushing system, a temperature control system and a gas content measuring system. The gas content measuring system comprises a desorption tank and a gas content measuring instrument connected with each other. The vibration crushing system comprises a vibration exciter and steel balls. The vibration exciter can drive the desorption tank to move. The steel balls are located in the interior of the desorption tank. The temperature control system is used for controlling the temperature of the desorption tank. The liquid nitrogen freezing system comprises a liquid nitrogen tank connected with the desorption tank. The gas pressurizing system comprises a gas cylinder and a booster pump. The gas cylinder, the booster pump and the desorption tank are connected in sequence. The application also provides a full-diameter core gas content measuring method, which is carried out in the above measuring device. The measuring device provided by the application can crush the sample in a sealed environment, reduce gas loss, has high crushing efficiency, requires short time, and can realize on-site measurement of the gas content.

Description

Technical Field

[0001] This invention relates to a gas content measuring device, and more particularly to a gas content measuring device and method for full-diameter core samples. Background Technology

[0002] Gas content is a crucial parameter in the coalbed methane (CBM) field, used for CBM resource evaluation and recoverability assessment. Therefore, accurate gas content measurement is paramount. The gas content determination method in GB / T 19559-2008 is followed. This involves placing a field-collected coal sample into a sealed desorption vessel and directly measuring the desorbed gas using a measuring instrument. After the desorbed gas measurement, the sample is crushed to measure the residual gas. The loss gas is measured using the direct method (USBM), utilizing the linear relationship between the cumulative desorbed gas volume, loss gas time, and desorption time to calculate the intercept. The gas content is the sum of the desorbed gas volume, residual gas volume, and loss gas volume. An error in measuring any of these components will affect the final gas content calculation result, making the desorbed gas measurement particularly critical.

[0003] Numerous patents exist related to desorbed gas measurement. CN204882291U provides a coalbed methane gas content measuring device that uses a metering tube to measure the coalbed methane volume, automatically reading, recording, storing, and calculating data. It boasts high detection accuracy, small systematic error, and a wide linear detection range. CN203287360U provides a gas content measuring device that can automatically, continuously, and accurately measure the gas content of shale gas, coalbed methane, etc., and can collect desorbed gas for gas composition analysis. It is also simple to operate and highly safe. However, the above methods all involve directly placing the coal sample collected on-site into a container for measurement. For large coal samples, the coalbed methane in the small pores is sealed and cannot be desorbed, leading to an underestimation of the desorbed gas volume. If large coal samples are first manually crushed before being placed into a container for desorption, gas loss occurs during the crushing process, resulting in an underestimation of the measured gas volume.

[0004] It can be seen that existing studies all involve long-term measurements of core samples or accelerating the testing process by heating. After the test, the desorption vessel needs to be opened to select 50-100g of sample for residual gas measurement. It is impossible to test the total gas content of a full-diameter core in 3 hours (or even faster). Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a device and method for measuring the gas content of full-diameter core samples. This device can crush samples in a sealed environment, reducing gas loss, and offers high crushing efficiency and simple operation.

[0006] To achieve the above objectives, the present invention provides a full-diameter core gas content measurement device, which includes: a gas pressurization system, a liquid nitrogen freezing system, a vibration crushing system, a temperature control system, and a gas content measurement system; wherein, the gas content measurement system includes a desorption tank and a gas content measuring instrument connected to each other, the desorption tank being used to contain the sample; the vibration crushing system includes a vibrator and steel balls, the vibrator being able to drive the movement of the desorption tank; the steel balls are located inside the desorption tank (the steel balls are in a free state inside the desorption tank); the temperature control system is used to control the temperature of the desorption tank; the liquid nitrogen freezing system includes a liquid nitrogen tank, the liquid nitrogen tank being connected to the desorption tank and used to supply liquid nitrogen to the desorption tank; the gas pressurization system includes a gas cylinder and a booster pump, the gas cylinder, the booster pump, and the desorption tank being connected in sequence.

[0007] In the aforementioned gas content measuring device, a pressure sensor is generally provided between the booster pump and the desorption tank. This pressure sensor is used to monitor the gas delivery pressure from the booster pump to the desorption tank.

[0008] In the above-mentioned gas content measuring device, the vibration crushing system may further include a desorption tank fixing platform, wherein the desorption tank is fixed to one side of the desorption tank fixing platform and the other side of the desorption tank fixing platform is connected to the vibrator, and the desorption tank and the vibrator are indirectly connected through the desorption tank fixing platform.

[0009] In the aforementioned gas content measuring device, the temperature control system generally includes a constant temperature chamber, and the desorption tank is located inside the constant temperature chamber, thereby enabling the constant temperature chamber to regulate the temperature of the desorption tank.

[0010] According to a specific embodiment of the present invention, the constant temperature chamber is generally equipped with a temperature sensor for monitoring the temperature of the chamber. Specifically, the constant temperature chamber may include a chamber body, a heater, a radiator, and a temperature sensor.

[0011] In the aforementioned gas content measuring device, the liquid nitrogen refrigeration system generally also includes a waste liquid tank, which is connected to the desorption tank and is used to receive the waste liquid (usually liquid nitrogen) discharged from the waste liquid tank.

[0012] In the aforementioned gas content measuring device, the desorption container generally includes an outer shell, an inner liner, and a top cover. When the top cover is locked to the outer shell, a sealed space is formed inside the desorption container. In some specific embodiments, the outer shell can be made of steel, and the inner liner can be made of aluminum alloy, which helps to reduce the vaporization rate of liquid nitrogen.

[0013] In the above-mentioned gas content measuring device, the desorption tank is generally provided with a first interface, a second interface, and a third interface. The first interface is connected to the outlet of the liquid nitrogen tank and is used to receive liquid nitrogen delivered by the liquid nitrogen tank. The second interface is connected to the outlet of the booster pump and is used to receive gas delivered by the booster pump. The third interface is connected to the inlet of the gas content measuring instrument and enables the gas content measuring instrument to detect the gas in the desorption tank.

[0014] In a specific embodiment of the present invention, the desorption tank may also be provided with a fourth interface, which is used to discharge waste liquid and is generally connected to the waste liquid tank.

[0015] In the aforementioned gas content measuring device, the desorption tank is generally also connected to an venting channel for discharging the gas from the desorption tank. Specifically, the venting channel may typically be equipped with a vent valve.

[0016] In a specific embodiment of the present invention, valves are provided between the desorption tank and the structures connected to it (booster pump, liquid nitrogen tank, gas content measuring instrument, waste liquid tank, etc.) to control the communication relationship between each structure and the desorption tank.

[0017] In a specific embodiment of the present invention, the above-mentioned device may further include a computer control system, which can be used to receive and analyze data collected by the gas content measuring instrument, control the operation of the booster pump, monitor the pressure and temperature in the device, and control the opening and closing of each valve.

[0018] The present invention also provides a method for measuring the gas content of a full-diameter core sample, wherein the measurement method is performed in the aforementioned full-diameter core gas content measuring device, and the measurement method includes:

[0019] S2. Measurement of gas loss: With the device in good airtight condition, the temperature inside the desorption vessel is kept stable by the temperature control system. The sample is placed in the desorption vessel and the sealed desorption vessel is connected to the gas content measuring instrument. The sample undergoes natural desorption in the desorption vessel. The cumulative gas volume collected in the above process is recorded by the gas content measuring instrument to obtain the gas loss.

[0020] S4. Freezing treatment: Connect the desorption vessel in a sealed state to the liquid nitrogen tank (at this time, the desorption vessel is only connected to the liquid nitrogen tank), inject liquid nitrogen into the desorption vessel until the sample is submerged, freeze the sample, and then drain the liquid nitrogen;

[0021] S6. Measurement of desorption volume at room temperature: Connect the desorption container in a sealed state to a vibrator. The vibrator drives the desorption container and steel balls to move. The sample is broken into fine particles by the impact of the steel balls. Connect the desorption container to a gas content measuring instrument. Record the cumulative gas volume and data acquisition time through the gas content measuring instrument. Calculate the ratio of the cumulative gas volume (i.e., the cumulative volume of gas released after breakage) to the sample mass to obtain the desorption volume at room temperature.

[0022] S8. Measurement of desorption gas volume during heating: Maintain the connection between the desorption vessel and the gas content measuring instrument (at this time, the desorption vessel is only connected to the gas content measuring instrument). Use the temperature control system to control the heating of the desorption vessel. Record the cumulative gas volume and data acquisition time through the gas content measuring instrument. Calculate the ratio of the cumulative gas volume (i.e., the cumulative volume of gas released after heating) to the sample mass to obtain the desorption gas volume during heating.

[0023] S10. The sum of the gas loss, the desorption at room temperature, and the desorption at elevated temperature is the gas content of the sample.

[0024] In the above-mentioned gas content measurement method, the diameter of the sample before measurement (i.e., before measurement) is generally 6-12 cm, and the weight is generally 1000-3000 g.

[0025] In the above-mentioned gas content measurement method, by utilizing the synergistic effect of freezing the sample with cryogenic liquid nitrogen (after repeated rinsing and soaking) and the impact of steel balls on the frozen sample, the sample can be more fragmented and the fragmentation speed can be faster.

[0026] During the above measurement process, the desorption tank being in a closed state means that all valves in the device are closed and the desorption tank is not connected to other structures.

[0027] In the above gas content measurement method, the average particle size of the fine particles formed after sample crushing in step S6 is generally less than 1 μm.

[0028] In the above-described gas content measurement method, among the fine particles formed after sample crushing in step S6, 10% of the fine particles have a diameter of less than 640 nm, and 90% of the fine particles have a diameter of less than 7 μm. In some specific embodiments, the above crushing process can be performed once or several times until the sample is crushed into fine particles of a certain size.

[0029] In the above gas content measurement method, in S2, the natural desorption time is 40-60 min.

[0030] In the above gas content measurement method, in step S4, the freezing time of the sample is generally 10 minutes.

[0031] In the above gas content measurement method, in S4, the time for discharging liquid nitrogen is generally controlled to be less than 5 minutes.

[0032] In the above gas content measurement method, in S6, by breaking the sample under sealed conditions, the desorbed gas can be measured more accurately.

[0033] In the above gas content measurement method, in S6, the measurement time for desorbed gas at room temperature is generally less than 60 minutes, for example less than 30 minutes.

[0034] In the above gas content measurement method, in S8, the measurement time for the desorbed gas volume during heating is generally less than 30 minutes.

[0035] In the above-described gas content measurement method, in step S6, the vibrator can drive the desorption tank and steel balls to perform near-circular and simple harmonic motion. In some specific embodiments, the rotational speed of the vibrator can be 700-2000 r / min.

[0036] In the above gas content measurement method, in step S2, the temperature of natural desorption is set according to the temperature of the reservoir where the corresponding sample is located. In a specific implementation, the temperature of natural desorption is the temperature of the reservoir where the sample is located (generally 30-90℃).

[0037] In the above-described gas content measurement method, in step S8, the heating operation allows for more complete escape of residual gas from the sample. Compared to existing methods that select a portion of the broken sample for residual gas measurement to estimate the overall gas content, the method of this invention can directly and more accurately measure the total residual gas content of the broken sample, thereby improving the accuracy of the measured gas content results. In some specific embodiments, the temperature for measuring the desorbed gas content can be 105-110℃.

[0038] According to a specific embodiment of the present invention, before performing S2, the measurement method may generally include: S1, airtightness check: sealing the desorption tank (that is, locking the top cover of the desorption tank to the outer shell), disconnecting the connection between the desorption tank and the liquid nitrogen freezing system and the gas content measuring instrument, connecting the desorption tank and the booster pump, using the gas cylinder and the booster pump to send gas to the desorption tank, detecting the gas supply pressure between the booster pump and the desorption tank, and when the pressure remains stable for a period of time (for example, the gas supply pressure is 3MPa, and the pressure remains stable for 10 minutes), then the device has good airtightness.

[0039] The beneficial effects of this invention are as follows:

[0040] The measuring device provided by this invention can achieve rapid and thorough crushing of samples on-site, thereby enabling on-site measurement of gas content in full-diameter core samples. The measurement method of this invention offers fast measurement and result acquisition speed, completing on-site gas content measurement and obtaining results within 3 hours. Compared to existing measurement methods that require several days to obtain results, the measurement method provided by this invention can meet the urgent need for data on-site. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the full-diameter core desorption measurement device in Example 1.

[0042] Figure 2 This is a schematic diagram of the desorption vessel in Example 1.

[0043] Symbol Explanation

[0044] 1. Gas cylinder, 2. Booster pump, 3. Liquid nitrogen tank, 4. Waste liquid tank, 5. Liquid nitrogen input pipeline, 6. Gas delivery pipe, 7. Valve, 8. Pressure sensor, 9. Valve, 10. Vent valve, 11. Valve, 12. Valve, 13. Waste liquid discharge pipeline, 14. Steel ball, 15. Desorption tank, 16. Desorption tank mounting platform, 17. Vibrator, 18. Constant temperature chamber, 19. Temperature sensor, 20. Radiator, 21. Heater, 22. Gas content measuring instrument, 23. Computer control system, 24. Data cable, 25. First interface, 26. Second interface, 27. Third interface, 28. Top cover of desorption tank, 29. Outer shell of desorption tank, 30. Inner liner of desorption tank, 31. Fourth interface. Detailed Implementation

[0045] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0046] Example 1

[0047] This embodiment provides a full-diameter core desorption measurement device, the structure of which is as follows: Figure 1 As shown. The device specifically includes a gas pressurization system, a liquid nitrogen refrigeration system, a vibration crushing system, a temperature control system, a gas content measurement system, and a computer control system 23.

[0048] The gas content measurement system includes a desorption tank 15 and a gas content measuring instrument 22 that are connected to each other. For example... Figure 2As shown, the desorption container 15 includes an outer shell 29, an inner liner 30, and a top cover 28. The top cover 28 of the desorption container has a first interface 25, a second interface 26, and a third interface 27 communicating with the internal space. The outer shell 29 of the desorption container has a fourth interface 31 communicating with the internal space. The top cover 28 of the desorption container is connected to a venting channel, which is equipped with a vent valve.

[0049] The temperature control system includes a constant temperature chamber 18, which is used to control the temperature of the desorption vessel 15. The constant temperature chamber 18 is equipped with a heater 21, a radiator 20 (a fan in this embodiment) and a temperature sensor 19, which is used to monitor the temperature of the heater 21, the radiator 20 and the desorption vessel 15.

[0050] The vibration crushing system includes a desorption tank mounting platform 16, a vibrator 17, and steel balls 14. The lower part of the desorption tank mounting platform 16 is connected to the vibrator 17, and the upper part of the platform is used to fix the desorption tank 15. The steel balls 14 are located inside the desorption tank 15. The vibrator can perform simple harmonic motion and near-circular motion, and its rotational speed can reach 700-2000 r / min.

[0051] The liquid nitrogen refrigeration system includes a liquid nitrogen tank 3 and a waste liquid tank 4. The liquid nitrogen tank 3 is used to supply liquid nitrogen to the desorption tank 15, and the waste liquid tank 4 is used to receive the liquid nitrogen discharged from the desorption tank 15.

[0052] The gas pressurization system includes a gas cylinder 1 (in this embodiment, a helium cylinder) and a booster pump 2 connected to each other. Specifically, the inlet of the booster pump 2 is connected to the outlet of the gas cylinder 1.

[0053] The connections between the systems are as follows:

[0054] The outlet of liquid nitrogen tank 3 is connected to the first interface 25 of desorption tank 15 via liquid nitrogen input pipeline 5, which is equipped with valve 11.

[0055] The outlet of the booster pump 2 is connected to the second interface 26 of the desorption tank 15 via a gas guide pipe 6, which is equipped with a valve 7 and a pressure sensor 8.

[0056] The inlet of the gas content measuring instrument 22 is connected to the third interface 27 of the desorption tank 15, and a valve 9 is provided between the two.

[0057] The inlet of the waste liquid tank 4 is connected to the fourth interface 31 of the desorption tank 15 through the waste liquid discharge pipeline 13, which is equipped with a valve 12.

[0058] The computer control system 23 is used to receive and analyze the data collected by the gas content measuring instrument 22, control the operation of the booster pump 2, monitor the pressure and temperature in the device, and control the opening and closing of each valve. In this embodiment, the computer control system 23 is connected to the booster pump 2, the gas content measuring instrument 22, valve 7, pressure sensor 8, valve 9, vent valve 10, valve 11, valve 12, and temperature sensor 19 via data cable 24.

[0059] Example 2

[0060] This embodiment provides a method for measuring the gas content of a full-diameter core sample, the method comprising:

[0061] S1. Air tightness test:

[0062] Tighten the top cover 28 of the desorption canister 15 to seal the inside of the desorption canister 15. Then connect the first port 25 of the desorption canister 15 to the gas guide pipe 6 to connect the desorption canister 15 to the booster pump 2 and the gas cylinder 1. Close all valves in the device (i.e. disconnect the connection between the desorption canister 15 and other structures). While turning on the booster pump 2, open valve 7 to inject helium into the inside of the desorption canister 15 until the pressure sensor 8 detects that the gas pressure between the booster pump 2 and the desorption canister 15 is 3MPa. Stop injecting gas. Monitor the pressure between the booster pump 2 and the desorption canister 15 through the pressure sensor 8. If the pressure can be maintained stably for 10 minutes, it is considered that the device is airtight and the following gas content measurement can continue.

[0063] S2, Measurement of Gas Loss:

[0064] With the device in good airtight condition, the temperature of the constant temperature chamber 18 is adjusted to the reservoir temperature where the sample is located through the heater 21 and radiator 20, thereby allowing the desorption tank 15 inside the constant temperature chamber to reach the reservoir temperature where the sample is located (generally 30-90℃). Using a full-diameter core sample collected on-site as the sample, the sample weight is measured, and then the sample is placed inside the desorption tank 15, and the top cover 28 of the desorption tank is tightened. All valves in the system are closed, and valve 9 is opened to allow the sample to undergo natural desorption for 40-60 minutes. During the natural desorption process, the cumulative amount of gas released from the desorption tank after the sample is placed is measured using the gas content measuring instrument 22, and the collection time is recorded to obtain the amount of gas lost (which can be calculated according to GB / T19559-2008 "Method for Determination of Coalbed Methane Content"), denoted as Q1.

[0065] S4. Freezing treatment:

[0066] Stop the operation of the constant temperature chamber 18, close all valves of the device, and only open valves 10 and 11 to connect the desorption tank 15 to the liquid nitrogen tank 3 and the venting channel respectively. Quickly inject liquid nitrogen into the desorption tank 15 through the liquid nitrogen tank 3 until the liquid nitrogen completely submerges the sample, and then stop the injection. Keep the sample submerged in liquid nitrogen for 10 minutes, open valve 12, and discharge the liquid nitrogen through the waste liquid discharge pipeline to the waste liquid tank 4. After the liquid nitrogen is completely discharged, close valve 12. The operation of discharging liquid nitrogen should be completed within 5 minutes.

[0067] S6. Measurement of desorption volume at room temperature:

[0068] Close all valves to keep the internal space of the desorption tank 15 sealed. Fix the desorption tank 15 above the desorption tank fixing platform 16. Control the vibrator 17 to perform near-circular or simple harmonic motion through the computer control system 23. The rotation speed of the vibrator 17 is 700-2000 r / min (the vibration frequency and rotation speed can be adjusted according to the type of sample). The desorption tank 15 moves together with the vibrator 17. The steel balls 14 inside the desorption tank 15 reciprocate and impact each other inside the tank. The sample treated with liquid nitrogen is broken down once or several times under the impact of the steel balls 14, forming micron-sized fine particles within a few minutes (specifically, 10% of the fine particles have a diameter of 640 nm and 90% of the fine particles have a diameter of less than 7 μm).

[0069] Open valve 9 to connect desorption tank 15 to gas content measuring instrument 22 (connection can begin at the start of the impact or after the impact). At room temperature, use gas content measuring instrument 22 to measure the cumulative gas volume released during the crushing process, and calculate the ratio of this gas volume to the sample mass; this is the room temperature desorption gas volume Q. 21 The total time for the above measurement process is 60 minutes;

[0070] S8. Measurement of desorption gas volume during temperature rise:

[0071] Run the constant temperature chamber 18 and set its temperature to 105℃. Use the gas content measuring instrument 22 to measure the cumulative amount of gas released in the desorption vessel during the heating phase and after the temperature stabilizes. Calculate the ratio of the released gas volume to the sample mass, which is the desorption gas volume Q during the heating phase. 22 The total time for the above measurement process is 30 minutes;

[0072] S10, Calculate the total gas content Q t According to Q t =Q1+Q 21 +Q 22 The formula (where all parameters are in the same volume unit) is used to calculate the total gas content Q. t .

[0073] The entire process can be completed within 3 hours.

[0074] Example 3

[0075] The test sample information is as follows: weight 3000g, cylindrical shape, diameter 8cm, height 30cm.

[0076] The gas content of the sample was measured according to the method in Example 2, and the measured gas content was 18.72 m³. 3 / t.

[0077] According to the natural desorption gas content test method provided in GB / T 19559-2008 "Method for Determination of Coalbed Methane Content", the gas content of this sample was found to be 18.25 m³. 3 / t.

[0078] A comparison of the above results shows that the measurement results obtained by the method provided by this invention are close to those obtained by existing methods, indicating that the method of this invention has high accuracy. Further comparison shows that the measurement results of this invention are slightly higher than those of the conventional natural desorption gas content testing method. This is because the conventional method randomly selects a portion of the sample from the intact sample when measuring residual gas, and gas loss occurs during the process of opening the sample container, breaking it, and placing it into the residual gas instrument, resulting in a lower test result relative to the true gas content of the sample. Therefore, the measurement method provided by this invention has higher accuracy than existing methods.

[0079] The full-diameter core gas content measurement method provided by this invention has high sample crushing efficiency, requires less time, can effectively reduce gas loss, provides accurate and reliable results, is easy to operate, and can realize on-site gas content measurement.

Claims

1. A method for measuring the gas content of a full-diameter core sample, wherein the method is performed in a full-diameter core gas content measuring device, the device comprising: Gas pressurization system, liquid nitrogen refrigeration system, vibration crushing system, temperature control system, and gas content measurement system; The gas content measurement system includes a desorption container and a gas content measuring instrument connected to each other, wherein the desorption container is used to contain the sample; The vibration crushing system includes a vibrator and steel balls; the vibrator can drive the desorption tank to move; the steel balls are located inside the desorption tank. The temperature control system is used to control the temperature of the desorption vessel; The liquid nitrogen freezing system includes a liquid nitrogen tank, which is connected to the desorption tank and is used to supply liquid nitrogen to the desorption tank. The gas pressurization system includes a gas cylinder and a booster pump, and the gas cylinder, booster pump and desorption tank are connected in sequence. A pressure sensor is provided between the booster pump and the desorption tank; The vibration crushing system further includes a desorption tank fixing platform, wherein the desorption tank is fixed to one side of the desorption tank fixing platform and the other side of the desorption tank fixing platform is connected to the vibrator; The temperature control system includes a constant temperature chamber, and the desorption vessel is located inside the constant temperature chamber; The constant temperature chamber is equipped with a temperature sensor; The liquid nitrogen refrigeration system also includes a waste liquid tank, which is connected to the desorption tank. The desorption tank is provided with a first interface, a second interface, and a third interface. The first interface is connected to the outlet of the liquid nitrogen tank, the second interface is connected to the outlet of the booster pump, and the third interface is connected to the inlet of the gas content measuring instrument. The desorption tank is also provided with a fourth port, which is used to discharge waste liquid; The measurement method includes: S2. Measurement of gas loss: With the device in good airtight condition, the temperature inside the desorption vessel is kept stable by the temperature control system. The sample is placed in the desorption vessel and the sealed desorption vessel is connected to the gas content measuring instrument. The sample undergoes natural desorption in the desorption vessel. The cumulative gas volume and data acquisition time collected during the above process are recorded by the gas content measuring instrument to obtain the gas loss. S4. Freezing treatment: Connect the sealed desorption vessel to the liquid nitrogen tank, inject liquid nitrogen into the desorption vessel until the sample is submerged, freeze the sample, and then drain the liquid nitrogen. S6. Measurement of desorption gas volume at room temperature: Connect the desorption container in a sealed state to a vibrator. The vibrator drives the desorption container and steel balls to move. The sample is broken into fine particles by the impact of the steel balls. Among the fine particles formed by the sample, the average particle size is less than 1 μm; 10% of the fine particles have a particle size of less than 640 nm, and 90% of the fine particles have a particle size of less than 7 μm. Connect the desorption container to a gas content measuring instrument. Record the cumulative gas volume and data acquisition time through the gas content measuring instrument. Calculate the ratio of the cumulative gas volume to the sample mass during the above process to obtain the desorption gas volume at room temperature. S8. Measurement of desorption gas volume during heating: Maintain the connection between the desorption vessel and the gas content measuring instrument, control the heating of the desorption vessel using the temperature control system, record the cumulative gas volume and data acquisition time through the gas content measuring instrument, calculate the ratio of the cumulative gas volume to the sample mass, and obtain the desorption gas volume during heating. S10. The sum of the gas loss, the amount of gas desorbed at room temperature, and the amount of gas desorbed upon heating is the gas content of the sample. The above measurement method can complete the on-site gas content measurement and obtain the results within 3 hours.

2. The gas content measurement method according to claim 1, wherein, The sample had a diameter of 6-12 cm and a weight of 1000-3000 g before measurement.

3. The gas content measurement method according to claim 1, wherein, The natural desorption time is 40-60 minutes; The sample was frozen for 10 minutes. The measurement time for desorption at room temperature should be less than 60 minutes; The measurement time for desorption gas volume during heating should be less than 30 minutes.

4. The gas content measurement method according to claim 1, wherein, In S6, the vibrator can drive the desorption tank and steel balls to perform near-circular and simple harmonic motion; the rotational speed of the vibrator is 700-2000 r / min.

5. The gas content measurement method according to claim 1, wherein, In S2, the temperature of natural desorption is the temperature of the reservoir where the sample is located; In S8, the temperature at which the desorption gas volume is measured during the heating process is 105-110℃.

6. The gas content measurement method according to claim 1, wherein, Before performing S2, the measurement method further includes: S1, airtightness check: seal the desorption tank, disconnect the connection between the desorption tank and the liquid nitrogen refrigeration system and the gas content measuring instrument, connect the desorption tank and the booster pump, use the gas cylinder and the booster pump to send gas to the desorption tank, and detect the gas supply pressure between the booster pump and the desorption tank. When the pressure remains stable for a period of time, the device has good airtightness.

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