Coal mine underground gas pressure deep hole pressure measuring device and pressure measuring method

Abstract

The invention belongs to the technical field of coal mine gas prevention and control, and relates to a coal mine underground gas pressure deep hole pressure measuring device and pressure measuring method.The coal mine underground gas pressure deep hole pressure measuring device comprises a compressed air pressurizing device, a drill rod, an expansion packer and an integrated pressure measuring instrument, the compressed air pressurizing device is communicated with the expansion packer through a drill rod, so that high-pressure gas is pumped into the expansion packer, the expansion packer is expanded, the bottom space of a drill hole is sealed to form a pressure measuring gas chamber, and the integrated pressure measuring instrument is used for measuring and storing the gas pressure of the pressure measuring gas chamber. The directional long drill hole with the length of hundreds of meters can be directly constructed in the deep coal seam to be measured, then the coal seam gas pressure value is directly measured through the coal mine underground gas pressure deep hole pressure measuring device and method, and compared with a traditional method, the construction cost is greatly reduced, and the construction period is greatly shortened.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine gas prevention and control, and relates to a deep hole pressure measuring device and a pressure measuring method for gas pressure in an underground coal mine. Background Art

[0002] As one of the basic parameters in coal mine safety production, coal seam gas pressure is the key to gas extraction, gas disaster prevention and control, and identification of coal and gas outburst hazards. At the same time, coal seam gas pressure is also one of the prominent prediction indicators for coal mine safety production at home and abroad. Accurately obtaining this parameter has important practical significance for gas extraction, gas disaster prevention and control, and identification of coal and gas outburst hazards. There are usually two methods for measuring gas pressure in coal seams: one is direct measurement of coal seam gas pressure, and the other is indirect measurement of coal seam gas pressure. The principle of the direct measurement method is to construct a pressure measuring borehole in the coal seam to be measured, and then use sealing means to seal the borehole. After the sealing is completed, a completely closed pressure measuring chamber is formed. After the gas flows into the pressure measuring chamber to reach pressure balance, the gas pressure is read according to the orifice pressure gauge; the indirect pressure measurement method is to reversely calculate the gas pressure based on the gas content to indirectly obtain the coal seam gas pressure. At present, the direct measurement method is affected by the drilling length and sealing technology and cannot measure the gas pressure of deep coal seams. The indirect measurement method back-calculates the gas pressure based on the gas content and cannot ensure the accuracy of the final conclusion.

[0003] Secondly, at present, my country's coal mines mainly use direct pressure measurement to measure coal seam gas pressure. Generally, the designed geological exploration boreholes or special boreholes are constructed from the tunnel to the coal seam and sealed with steel pipes to transmit the pressure to the outside of the hole. Pressure gauges are installed outside the hole to collect data, so as to directly measure the coal seam gas pressure. However, the length of these two types of boreholes can generally only reach a dozen meters to dozens of meters, and it is impossible to simply measure the gas pressure of deep coal seams. Therefore, if the existing technology is to measure the gas pressure value of deep coal seams, it is necessary to specially open a tunnel near the coal seam to be measured, and then construct a pressure measurement borehole to measure the gas pressure. However, this process requires a large number of special tunnel development, the construction cost is too high and the construction period is long, which is difficult to meet the actual needs of coal mine production and engineering.

[0004] Therefore, it is urgent to propose a new deep hole pressure measuring device and pressure measuring method for underground coal mine gas pressure, break through the limitations of drilling length and sealing process, so as to directly measure the gas pressure of deep coal seams to meet the actual needs of underground coal mine engineering. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a deep hole pressure measuring device and pressure measuring method for underground coal mine gas pressure, which breaks through the limitations of drilling length and sealing process, so that the gas pressure of deep coal seams can be directly measured to meet the actual needs of underground coal mine engineering.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A deep hole pressure measuring device for gas pressure in coal mines, characterized by comprising a compressed air booster, a drill pipe, an expansion packer and an integrated pressure measuring instrument connected in sequence;

[0008] The compressed air booster device is connected to the expansion packer through the drill pipe to pump high-pressure gas into the expansion packer, so as to expand the expansion packer and seal the bottom space of the borehole to form a pressure measuring chamber. The integrated pressure measuring instrument is used to measure and store the gas pressure of the pressure measuring chamber.

[0009] The compressed air boosting device comprises a high-pressure hose, a pressure gauge, a high-pressure valve and a gas boosting pump which are sequentially connected to the rear end of the drill pipe;

[0010] The integrated pressure measuring instrument comprises a shell, a pressure sensor, a data storage device and a battery. The shell comprises two sections of sub-shells that are independent of each other, and the sub-shell near one end of the expansion packer is a first shell. The first shell is used to place the pressure sensor and the data storage device connected to the pressure sensor, and is connected to a protection head at one end near the expansion packer. The protection head is provided with a channel connected to the pressure measuring chamber so that the pressure sensor can measure the gas pressure of the pressure measuring chamber and is connected to the expansion packer through the protection head.

[0011] The outer side of one end of the first shell away from the expansion packer is used to place a battery electrically connected to the data storage device. The other sub-shell in the shell is a second shell, and the second shell is sleeved on one end of the first shell away from the expansion packer to seal the battery to prevent the battery from contacting external gas.

[0012] Furthermore, an adapter and a sealing adapter for connecting a drill pipe and an integrated pressure tester are respectively provided at both ends of the expansion packer, and the protection head is connected to the expansion packer via the sealing adapter.

[0013] Furthermore, pressure-resistant sealing rings are sleeved on both ends of the battery on the first shell to ensure the sealing effect of the second shell on the battery.

[0014] A method for measuring gas pressure in a deep hole in a coal mine, providing a device for measuring gas pressure in a deep hole in a coal mine, specifically comprising the following steps:

[0015] Preparation: Before the pressure test, debug the integrated pressure tester and set the corresponding measurement parameters according to the geological conditions and pressure test requirements of the pressure test site;

[0016] Formal work:

[0017] Step 1: Drilling operations are carried out underground;

[0018] Step 2: After the drilling operation is completed, the drill is withdrawn, and the adapter, expansion packer, sealing adapter and integrated pressure measuring instrument are installed at the front end of the drill pipe in sequence, and then the coal mine gas pressure deep hole pressure measuring device is sent to the bottom of the borehole by means of drilling rig propulsion, and the end of the integrated pressure measuring instrument is kept at a distance from the bottom of the borehole, so as to form a pressure measuring air chamber after the expansion packer seals the borehole;

[0019] Step 3: After the integrated pressure measuring instrument is pushed into place, the high-pressure hose, pressure gauge, high-pressure valve and gas booster pump are connected to the tail end of the drill pipe in sequence, and then the gas booster pump is turned on to drive the high-pressure gas into the expansion packer, so that the expansion packer is fully expanded and completely sealed, and finally the high-pressure valve and gas booster pump are closed to complete the sealing operation of the borehole;

[0020] Step 4: Wait for the gas pressure in the pressure measuring chamber to be balanced, and measure the gas pressure value of the pressure measuring chamber by an integrated pressure measuring instrument;

[0021] Step 5: After the gas pressure measurement is completed, open the high-pressure valve to release the pressure, wait for 30 minutes, and after the expansion packer is completely contracted, withdraw the drill and remove the coal mine underground gas pressure deep hole pressure measuring device.

[0022] Step 6: After withdrawing the coal mine underground gas pressure deep hole pressure measuring device, bring the integrated pressure measuring instrument to the ground, connect it to the matching reader and computer to export the measurement data, and screen and process the measurement data to obtain the final gas pressure value.

[0023] Furthermore, in the third step, the pressure gauge reading is observed to determine whether the expansion packer has reached the starting pressure. After the pressure gauge reading reaches the expansion packer starting pressure, wait for 15 minutes to ensure that the expansion packer 3 is fully expanded and completely sealed, and then close the high-pressure valve and the gas booster pump.

[0024] Furthermore, in the fourth step, in order to improve the accuracy of the measurement results, it is necessary to wait for the gas pressure in the pressure measuring chamber to reach a balanced state before measuring, and the time for waiting for the gas pressure in the pressure measuring chamber to reach a balanced state is at least 15 days.

[0025] Furthermore, while waiting for the gas pressure in the pressure measuring chamber to reach a balanced state, it is necessary to continue to pay attention to the pressure gauge value. If the pressure gauge value drops, it is necessary to turn on the gas booster pump to perform a pressure replenishment operation.

[0026] The beneficial effects of the present invention are:

[0027] Compared with the current direct measurement method for measuring coal seam gas pressure, due to the influence of the process, the coal seam gas pressure can generally only be measured within a range of tens of meters. If deep coal seam gas pressure is to be measured, a special pressure measurement tunnel needs to be developed, which has huge construction costs and a long construction period, and cannot meet the requirements of normal underground production continuity.

[0028] The present invention provides a coal mine underground gas pressure deep hole pressure measuring device and pressure measuring method, provides a technical solution of using an expansion packer to expand and seal at the bottom of a borehole to form a pressure measuring air chamber, and measuring the gas pressure in the pressure measuring air chamber by an integrated pressure measuring instrument connected to the expansion packer. A directional long borehole several hundred meters long can be directly constructed into a deep coal seam to be tested, and then the coal mine underground gas pressure deep hole pressure measuring device and pressure measuring method provided by the present invention can be used to directly measure the gas pressure value of the coal seam. Compared with traditional methods, the construction cost and period are greatly reduced.

[0029] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0031] Figure 1 It is a construction schematic diagram of a deep hole pressure measuring device for gas pressure in a coal mine in an embodiment;

[0032] Figure 2 It is a schematic diagram of the results of the integrated pressure measuring instrument in the embodiment.

[0033] Figure numerals: 1-borehole; 2-adapter; 3-expansion packer; 4-sealing adapter; 5-integrated pressure measuring instrument; 6-pressure measuring chamber; 7-drill pipe; 8-high-pressure hose; 9-pressure gauge; 10-high-pressure valve; 11-gas booster pump; 12-protection head; 13-pressure sensor; 14-data storage device; 15-battery; 16-pressure-resistant sealing ring; 17-housing. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0035] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0036] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0037] See also Figure 1-2 , is a construction schematic diagram of a deep hole pressure measuring device for gas pressure in a coal mine. The pressure measuring principle of the pressure measuring method of the deep hole pressure measuring device for gas pressure in a coal mine is as follows:

[0038] The pressure measurement method uses a compressed air booster device (gas booster pump 11) to connect the drill pipe 7 to pump high-pressure gas into the expansion packer 3. Under the action of the high-pressure gas, the expansion packer 3 expands, seals the bottom space of the borehole 1, forms a pressure measurement chamber 6, and completely blocks the cracks around the borehole 1 to be pressure-measured, and completely seals the gas leakage channel of the pressure measurement chamber 6, thereby improving the accuracy of the measurement result. Then, the integrated pressure measuring instrument 5 connected to the upper end of the expansion packer 3 can be used to measure the gas pressure value in the pressure measurement chamber 6 and store the data. After the pressure measurement process is completed, the drill pipe 7, the expansion packer 3 and the integrated pressure measuring instrument 5 are withdrawn, the integrated pressure measuring instrument 5 is removed and connected to the reader and the computer, and the measurement data is analyzed and processed to obtain the gas pressure value of the coal seam in the borehole. This measurement method is a passive pressure measurement method, which has high precision, high stability and high reliability, and is an important means for coal mine safety production and scientific research.

[0039] The coal mine underground gas pressure deep hole pressure measuring device comprises an integrated pressure measuring instrument 5, an expansion packer 3, a drill rod 7 and a compressed air booster device;

[0040] like Figure 2 As shown, it is a schematic diagram of the structure of the integrated pressure measuring instrument 5. The integrated pressure measuring instrument 5 has a protective head 12 and a shell 17 made of all stainless steel and titanium alloy. It has high strength and good airtightness, and can protect the internal electrical devices from damage in the complex environment of the mine. The integrated pressure measuring instrument 5 has a built-in high-precision pressure sensor 13, a data storage device 14, a battery 15 and a pressure-resistant sealing ring 16. The measurement accuracy of the pressure sensor 13 is above 0.25% FS. Its high-precision characteristics enable it to provide more accurate data during the measurement process. At the same time, the data storage device 14 and the battery can collect and store data at regular intervals. The pressure-resistant sealing ring 16 can ensure the good sealing performance of the device, thereby providing more reliable protection for coal mine safety production.

[0041] Specifically, the shell 17 includes two sections of sub-shells that are independent of each other, and the sub-shell near one end of the expansion packer 3 is a first shell, a pressure sensor 13 and a data storage device 14 connected to the pressure sensor 13 are placed in the first shell, and a protection head 12 is connected to the end of the first shell near the expansion packer 3, and a channel connected to the borehole 1 is provided on the protection head 12, so that the pressure sensor 13 can accurately measure the gas pressure of the pressure measuring chamber; and a groove for placing a battery 15 electrically connected to the data storage device 14 is provided on the outer side of the end of the first shell away from the expansion packer 3, so as to place the battery 15, and the other section of the sub-shell in the shell 17 is a second shell, and the second shell is sleeved on the end of the first shell away from the expansion packer 3 to seal the battery 15 to prevent the battery 15 from contacting external gas;

[0042] Furthermore, pressure-resistant sealing rings 16 are sleeved on both ends of the battery on the first shell to ensure the sealing effect of the second shell on the battery.

[0043] The integrated pressure measuring instrument 5 is equipped with a dedicated reader and PC operating software. By connecting the reader and the computer, the operating software can be used to set parameters before measurement and read data after measurement on the integrated pressure measuring instrument 5. The integrated pressure measuring instrument provides a high-precision, high-stability and high-reliability pressure measurement method, which can be applied to a variety of scientific research and engineering application scenarios.

[0044] The expansion packer 3 has high strength and expansion rate. After being fully sealed, a sealed pressure measuring air chamber 6 can be formed between the bottom of the borehole, the coal wall and the expansion packer 3. At the same time, the cracks around the pressure measuring borehole can be completely blocked, and the gas leakage channel of the pressure measuring air chamber 6 can be completely sealed, thereby improving the accuracy of the measurement results.

[0045] Preferably, the expansion packer 3 is equipped with different outer diameter models, and its design adopts high-strength vulcanization process to ensure excellent airtightness and durability; and an adapter 2 (fluid can flow) and a sealing adapter 4 (fluid cannot flow) for connecting the drill pipe 7 and the integrated pressure tester 5 are respectively provided at both ends of the expansion packer 3;

[0046] The expansion packer 3 has a wide variety of design models and can be customized for different drilling pressure measurement requirements. It can also be matched with the adapter 2 and different models of drill pipes 7 to ensure the applicability and efficiency of the device. In actual use, the caliber and model of the device can be flexibly configured to meet various specific needs.

[0047] Furthermore, the drill pipe 7 is a high-pressure sealed drill pipe, and its main functions are: first, to send the integrated pressure tester 5 and the expansion packer 3 to the bottom of the borehole, and withdraw them after completing the pressure testing process; second, to serve as a high-pressure gas circulation channel to transport the high-pressure gas to the expansion packer 3 to expand and maintain it.

[0048] The compressed air boosting device includes a gas boosting pump 11, a high-pressure valve 10, a pressure gauge 9 and a high-pressure hose 8 which are connected in sequence along the flow direction of the high-pressure gas. The high-pressure gas is pumped by the gas boosting pump 11, flows through the high-pressure valve 10, the pressure gauge 9, the high-pressure hose 8 and the drill pipe 7, and then is filled into the expansion packer 3 to achieve inflation of the expansion packer 3. The compressed air boosting device has excellent pressure resistance and reliable sealing ability, which ensures the safety and accuracy of the measurement process.

[0049] Specifically, the adapter 2 is an open adapter (fluid can flow), the upper end of which is connected to the expansion packer 3, and the lower end is connected to the drill pipe 7; the sealing adapter 4 is a closed adapter (fluid cannot flow), the upper end of which is connected to the integrated pressure measuring instrument 5, and the lower end is connected to the expansion packer 3;

[0050] Preferably, the adapter 2 and the sealing adapter 4 have various calibers and models to meet the connection needs of different models of expansion packers 3 and drill pipes 7. The device has high flexibility and applicability and can adapt to a variety of different scenarios and application requirements.

[0051] A method for measuring gas pressure in a deep hole in a coal mine, the specific construction steps are as follows:

[0052] (1) Preparation: Before the pressure measurement, the integrated pressure tester 5 can be debugged using the supporting software; according to the geological conditions and pressure measurement requirements of the pressure measurement site, the corresponding measurement parameters are set to ensure the accuracy and reliability of the measurement results. During the debugging process, it is necessary to pay close attention to various indicators of the equipment, such as static and dynamic response, sampling frequency, accuracy, etc., to ensure the accuracy and stability of the measurement results.

[0053] (2) Formal work:

[0054] Step 1: Drilling in the well;

[0055] Carry out drilling operations underground.

[0056] Step 2: Drill back and arrange deep hole pressure measuring device;

[0057] After the drilling operation is completed, the drill is withdrawn, and the adapter, expansion packer, sealing adapter and integrated pressure measuring instrument are installed at the front end of the drill pipe in sequence, and then the deep hole pressure measuring device is sent to the bottom of the borehole by means of drilling rig propulsion. It should be noted that the end of the integrated pressure measuring instrument 5 at the front end should be kept at a certain distance from the bottom of the hole so that a closed pressure measuring air chamber 6 with sufficient space can be formed after the expansion packer is sealed.

[0058] Step 3: Suppress and seal;

[0059] After the integrated pressure measuring instrument 5 is pushed into place, the high-pressure hose 8, the pressure gauge 9, the high-pressure valve 10 and the gas booster pump 11 are connected in sequence at the rear end of the drill pipe 7 to form a compressed air booster device; then the gas booster pump 11 is turned on to drive the high-pressure gas into the expansion packer 3 along the gas channel. In this process, it can be judged whether the expansion packer 3 has reached the starting pressure by observing the reading of the pressure gauge. When the pressure gauge reading reaches the expansion packer starting pressure, wait for 15 minutes to ensure that the expansion packer 3 is fully expanded and completely sealed, and finally close the high-pressure valve 10 and the gas booster pump 11 to complete the sealing operation of the deep hole pressure measuring device.

[0060] Step 4: Wait for the gas pressure in the pressure measuring chamber to be balanced and measure the gas pressure value;

[0061] After the expansion packer 3 is completely set, the pressure measurement operation begins.

[0062] The integrated pressure measuring instrument 5 described in this embodiment can automatically measure and record the coal seam gas pressure value in the closed gas chamber. In order to improve the accuracy of the measurement results, it is necessary to wait for the gas pressure in the pressure measuring chamber to reach a balanced state before measuring. Therefore, the shortest measurement time of the deep hole pressure measuring device is 15 working days.

[0063] During the entire measurement process, it is necessary to keep an eye on the pressure gauge value. If the pressure gauge value drops, it is necessary to turn on the gas booster pump 11 to replenish the pressure. If the pressure gauge value drops significantly (drops by more than 0.5MPa), it means that the sealing system may have a leak. At this time, it is necessary to withdraw the drill pipe, withdraw the deep hole pressure measuring device, check the equipment, and then repeat the above process.

[0064] Step 5: Release the pressure, withdraw the drill, and remove the deep hole pressure measuring device;

[0065] After the gas pressure measurement is completed, the high-pressure valve 10 is opened to release the pressure, and after waiting for 30 minutes, the deep hole pressure measuring device is withdrawn after the expansion packer 3 is completely contracted.

[0066] Step 6: Export data and obtain gas pressure value;

[0067] After the pressure measuring device is withdrawn, the integrated pressure measuring instrument 5 is brought to the ground, and connected to a reader and a computer to export the measurement data, and the measurement data is screened and processed to obtain the final gas pressure value.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A deep hole pressure measuring device for gas pressure in coal mines, characterized in that: It includes a compressed air booster, a drill pipe, an expansion packer and an integrated pressure measuring instrument connected in sequence; The compressed air booster device is connected to the expansion packer through the drill pipe to pump high-pressure gas into the expansion packer, so as to expand the expansion packer and seal the bottom space of the borehole to form a pressure measuring chamber. The integrated pressure measuring instrument is used to measure and store the gas pressure of the pressure measuring chamber. The compressed air boosting device comprises a high-pressure hose, a pressure gauge, a high-pressure valve and a gas boosting pump which are sequentially connected to the rear end of the drill pipe; The integrated pressure measuring instrument comprises a shell, a pressure sensor, a data storage device and a battery. The shell comprises two sections of sub-shells that are independent of each other, and the sub-shell near one end of the expansion packer is a first shell. The first shell is used to place the pressure sensor and the data storage device connected to the pressure sensor, and is connected to a protection head at one end near the expansion packer. The protection head is provided with a channel connected to the pressure measuring chamber so that the pressure sensor can measure the gas pressure of the pressure measuring chamber and is connected to the expansion packer through the protection head. The outer side of one end of the first shell away from the expansion packer is used to place a battery electrically connected to the data storage device. The other sub-shell in the shell is a second shell, and the second shell is sleeved on one end of the first shell away from the expansion packer to seal the battery to prevent the battery from contacting external gas.

2. The deep hole pressure measuring device for gas pressure in underground coal mine according to claim 1, characterized in that: An adapter and a sealing adapter for connecting a drill pipe and an integrated pressure tester are respectively arranged at both ends of the expansion packer, and the protection head is connected to the expansion packer via the sealing adapter.

3. The deep hole pressure measuring device for gas pressure in coal mines according to claim 1, characterized in that: Pressure-resistant sealing rings are also sleeved on both ends of the battery on the first shell to ensure the sealing effect of the second shell on the battery.

4. A method for measuring gas pressure in a deep hole in a coal mine, characterized in that: A deep hole pressure measuring device for gas pressure in underground coal mines according to any one of claims 2 to 3 is provided, which specifically comprises the following steps: Preparation: Before the pressure test, debug the integrated pressure tester and set the corresponding measurement parameters according to the geological conditions and pressure test requirements of the pressure test site; Formal work: Step 1: Drilling operations are carried out underground; Step 2: After the drilling operation is completed, the drill is withdrawn, and the adapter, expansion packer, sealing adapter and integrated pressure measuring instrument are installed at the front end of the drill pipe in sequence, and then the coal mine gas pressure deep hole pressure measuring device is sent to the bottom of the borehole by means of drilling rig propulsion, and the end of the integrated pressure measuring instrument is kept at a distance from the bottom of the borehole, so as to form a pressure measuring air chamber after the expansion packer seals the borehole; Step 3: After the integrated pressure measuring instrument is pushed into place, the high-pressure hose, pressure gauge, high-pressure valve and gas booster pump are connected to the tail end of the drill pipe in sequence, and then the gas booster pump is turned on to drive the high-pressure gas into the expansion packer, so that the expansion packer is fully expanded and completely sealed, and finally the high-pressure valve and gas booster pump are closed to complete the sealing operation of the borehole; Step 4: Wait for the gas pressure in the pressure measuring chamber to be balanced, and measure the gas pressure value of the pressure measuring chamber by an integrated pressure measuring instrument; Step 5: After the gas pressure measurement is completed, open the high-pressure valve to release the pressure, wait for 30 minutes, and after the expansion packer is completely contracted, withdraw the drill and remove the coal mine underground gas pressure deep hole pressure measuring device. Step 6: After withdrawing the coal mine underground gas pressure deep hole pressure measuring device, bring the integrated pressure measuring instrument to the ground, connect it to the matching reader and computer to export the measurement data, and screen and process the measurement data to obtain the final gas pressure value.

5. The method for measuring gas pressure in deep holes in underground coal mines according to claim 4, characterized in that: In the third step, the pressure gauge reading is observed to determine whether the expansion packer has reached the starting pressure. After the pressure gauge reading reaches the starting pressure of the expansion packer, wait for 15 minutes to ensure that the expansion packer 3 is fully expanded and completely sealed, and then close the high-pressure valve and the gas booster pump.

6. The method for measuring gas pressure in deep holes in underground coal mines according to claim 5, characterized in that: In the fourth step, in order to improve the accuracy of the measurement results, it is necessary to wait for the gas pressure in the pressure measuring chamber to reach a balanced state before measuring. The time to wait for the gas pressure in the pressure measuring chamber to reach a balanced state is at least 15 days.

7. The method for measuring gas pressure in a deep hole in a coal mine according to claim 6, characterized in that: While waiting for the gas pressure in the pressure measuring chamber to reach a balanced state, it is necessary to continue to pay attention to the pressure gauge value. If the pressure gauge value drops, it is necessary to turn on the gas booster pump to replenish the pressure.

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