Directional long borehole bottom gas pressure active measuring device and measuring method

Abstract

This invention discloses an active device and method for measuring the bottom gas pressure of a directional long borehole. The active device for measuring the bottom gas pressure of a directional long borehole includes a first tube, a first sealing element, a second sealing element, a second tube, and a detection element. One end of the first tube is adapted to be inserted into the borehole, and the second end of the first tube extends out of the borehole. The first sealing element is located at the first end of the first tube and communicates with the first tube. The second sealing element is inserted into the first tube and communicates with the first tube. The second sealing element is adapted to be inserted into the borehole and is spaced apart from the first sealing element along the length of the first tube. The third end of the second tube is adapted to be inserted into the pressure measuring chamber and communicates with the pressure measuring chamber. The fourth end of the second tube extends out of the borehole. The second tube is adapted to introduce high-pressure gas. The detection element is located in the pressure measuring chamber. The active device for measuring the bottom gas pressure of a directional long borehole of this invention has the advantages of simple structure and accurate measurement results.

Description

Technical Field

[0001] This invention belongs to the field of coal mine safety technology, and in particular relates to an active measuring device and method for measuring gas pressure at the bottom of directional long boreholes. Background Technology

[0002] Coal seam gas pressure is the force generated by the collision of gas molecules during free thermal motion within the pores of the coal seam. All other things being equal, the higher the coal seam gas pressure, the greater the gas content in the coal, the greater the risk of coal and gas outbursts, and the greater the gas emission during coal seam mining. Therefore, coal seam gas pressure is a primary basis for identifying and predicting coal and gas outburst risks, designing extraction processes, and verifying outburst mitigation effectiveness.

[0003] In related technologies, coal seam gas pressure in underground coal mines is measured using short boreholes. After the borehole is constructed, it is cleaned and the drill rod is removed. The pressure measuring tube is then inserted into the borehole and sealed to form a closed pressure measuring chamber. A pressure gauge is installed at the outside of the borehole using the principle of communicating vessels to read the gas pressure value. However, short borehole measurements result in inaccurate test results and long measurement times. Summary of the Invention

[0004] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0005] In related technologies, the coal seam gas pressure measurement method has the following problems: (1) Due to the relatively loose coal seam structure or the large number of cracks generated by the coal and rock strata during roadway excavation, the sealing of the borehole is not tight, resulting in distorted gas pressure measurement values; (2) When the sealing grouting pipe is transported along the borehole, it is easy to rub against the borehole wall, causing damage to the grouting pipe and affecting the test results; (3) There is a pressure drop loss in the process of gas pressure being transmitted from the pressure measuring chamber to the borehole opening along the pressure measuring pipe, resulting in the measurement results being too small; (4) Due to the limitations of coal and rock roadway engineering and ordinary borehole construction technology, the ordinary borehole pressure measurement method cannot achieve long-distance coal seam gas pressure measurement. (5) Among the related technologies, the pressure measurement method lacks a rapid identification technology in the verification of pressure leakage; (6) The pressure measurement method has a short gas pressure measurement distance and relies heavily on roadway engineering pressure measurement, making it impossible to accurately test coal seam gas pressure over long distances; (7) The position of the grouting pipe and conductor laid along the line in the pressure measurement method cannot be controlled, and the grouting pipe and conductor are prone to friction with the borehole wall, causing damage; (8) The pressure measurement pipe in the pressure measurement method has pressure drop loss, which affects the accuracy and real-time performance of the measurement results; (9) The pressure measurement method cannot automatically identify gas leakage in the system during the pressure measurement process and issue an early warning.

[0006] The present invention aims to at least partially solve one of the technical problems in the related art.

[0007] Therefore, embodiments of the present invention propose an active measuring device for bottom gas pressure in directional long boreholes that provides accurate measurement results and has a short measurement time.

[0008] An active gas pressure measuring device for directional long boreholes according to an embodiment of the present invention includes: a first tube having a first end and a second end in its length direction, one end of the first tube being adapted to pass through a borehole, the second end of the first tube extending out of the borehole, and the first tube being adapted to introduce slurry; a first sealing member disposed at the first end of the first tube and communicating with the first tube, the first sealing member being adapted to pass through the borehole so that the first tube injects slurry into the first sealing member to expand the first sealing member and seal the borehole, and the first sealing member being spaced apart from the bottom of the borehole to form a pressure measuring chamber; a second sealing member passing through the first tube and communicating with the first tube, the second sealing member being adapted to pass through the borehole and spaced apart from the first sealing member along the length direction of the first tube so that the first tube injects slurry into the second sealing member to expand the second sealing member and seal the borehole; and a second tube having a first end and a second end in its length direction. The device has a third and a fourth end, with the third end of the second tube adapted to pass through and communicate with the pressure measuring chamber, and the fourth end of the second tube extending out of the borehole. The second tube is adapted to introduce high-pressure gas. A detection element is disposed within the pressure measuring chamber and is used to detect the pressure within the chamber. The directional long borehole bottom gas pressure active measuring device has a first state and a second state. In the first state, the first tube injects grout into the first and second seals to expand them, thus sealing the borehole. In the second state, when the pressure of one of the first and second seals is higher than a first preset value, the first tube injects grout into the area between the first and second seals so that the grout fills the crack in the borehole between the first and second seals, and the second tube introduces high-pressure gas into the pressure measuring chamber.

[0009] The gas pressure measuring device of this invention includes a grouting pipe, a first sealing component, a second sealing component, a detection component, and a second pipe. It can seal cracks in the borehole, ensuring the sealing of the pressure measuring chamber and the detection results of the detection component, reducing gas pressure loss, improving the accuracy of the measurement results, and achieving real-time reading.

[0010] In some embodiments, the active gas pressure measuring device at the bottom of the directional long borehole further includes a first valve, which is disposed on the side of the first seal facing the second seal. In the first state, the first end of the first pipe is connected to the first seal through the first valve, so that the first pipe injects grout into the first seal through the first valve to expand the first seal. In the second state, the first valve is disconnected from the first seal, so that the grout fills between the first seal and the second seal.

[0011] In some embodiments, the active gas pressure measuring device at the bottom of the directional long borehole further includes a centralizer, which is installed on the first pipe and the second pipe and is adapted to be installed inside the borehole. The centralizer is located on the side of the second seal away from the first seal and is spaced apart from the second seal along the length direction of the first pipe.

[0012] In some embodiments, the active gas pressure measuring device at the bottom of the directional long borehole further includes a third state and a fourth state. In the third state, when the pressure of the slurry between the first seal and the second seal is higher than a second preset value, the slurry will push the second seal to move toward the direction adjacent to the centralizer to expand the grouting range. In the fourth state, the second seal abuts against the centralizer so that when the pressure in the second seal is higher than the third preset value, the first pipe stops grouting.

[0013] In some embodiments, the active gas pressure measuring device at the bottom of the directional long borehole further includes a second valve, which is disposed on the second seal. In the first state, the second state, and the third state, the first pipe can inject grout into the second seal to cause the second seal to expand. In the fourth state, when the pressure inside the second seal is higher than a third preset value, the second valve is activated to reduce the pressure inside the second seal, and the first pipe stops injecting grout into the second seal.

[0014] In some embodiments, the active gas pressure measuring device at the bottom of the directional long borehole further includes an early warning detection element. The early warning detection element is disposed at the other end of the first tube and is adapted to be disposed outside the borehole. The early warning detection element is used to detect the gas concentration and gas pressure outside the borehole. When the early warning detection element detects that the gas concentration or gas pressure outside the borehole is higher than a preset value, the early warning detection element issues an alarm. The early warning detection element is connected to the detection element so that when the detection element detects that the pressure drop rate in the pressure measuring chamber is higher than a preset value, the early warning detection element issues an alarm.

[0015] In some embodiments, the active gas pressure measuring device at the bottom of the directional long borehole further includes a high-pressure gas cylinder, which is adapted to store high-pressure gas and is connected to the fourth end of the second tube so that the high-pressure gas cylinder supplies gas to the pressure measuring chamber through the second tube.

[0016] In some embodiments, the active gas pressure measuring device at the bottom of the directional long borehole further includes a grouting pump, which is located at the second end of the first pipe and communicates with the second end of the first pipe, so that the slurry is delivered into the first pipe through the grouting pump.

[0017] In some embodiments, the first seal is a packer and the second seal is a pressure-controlled capsule. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the active gas pressure measuring device at the bottom of a directional long borehole according to an embodiment of the present invention.

[0019] 100 Active Measurement Device for Bottom Gas Pressure in Directional Long Boreholes;

[0020] First pipe 1; First seal 2; Second seal 3; Second pipe 4; Detection element 5; First valve 6; Centralizer 7; Second valve 8; Early warning detection element 9; High-pressure gas cylinder 10; Grouting pump 11; Drill hole 12; Pressure measuring chamber 13; Sealing chamber 14. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] The active gas pressure measuring device at the bottom of a directional long borehole according to an embodiment of the present invention is described below with reference to the accompanying drawings.

[0023] like Figure 1 As shown, the active gas pressure measuring device 100 at the bottom of the directional long borehole according to an embodiment of the present invention includes a first tube 1, a first sealing element 2, a second sealing element 3, a second tube 4, and a detection element 5.

[0024] The first tube 1 in its length direction (e.g.) Figure 1 The first pipe 1 (shown in the left-right direction) has a first end and a second end. One end of the first pipe 1 is adapted to be inserted into the borehole 12, and the second end of the first pipe 1 extends out of the borehole 12. The first pipe 1 is adapted to allow slurry to pass through. Specifically, as shown... Figure 1 As shown, the first pipe 1 is a grouting pipe. The first end of the first pipe 1 is the grouting outlet, and the second end of the first pipe 1 is the grouting inlet. The first pipe 1 can be inserted into the borehole 12 so that grouting can be performed on the borehole 12 through the first pipe 1.

[0025] The first sealing element 2 is disposed at the first end of the first pipe 1 and communicates with the first pipe 1. The first sealing element 2 is adapted to pass through the borehole 12 so that the first pipe 1 injects grout into the first sealing element 2 to expand the first sealing element 2 and seal the borehole 12. The first sealing element 2 is spaced apart from the bottom of the borehole 12 to form a pressure measuring chamber 13. Specifically, as shown in the figure... Figure 1 As shown, the first sealing element 2 is located at the left end of the first pipe 1 and is connected to the grouting outlet of the first pipe 1. Grouting can be performed on the first sealing element 2 to cause it to expand, so that the outer peripheral surface of the first sealing element 2 fits against the inner peripheral surface of the drill hole 12, thereby sealing the drill hole 12. The first sealing element 2 and the bottom of the drill hole 12 (e.g., Figure 1 The left end face of the borehole 12 shown is spaced along the left and right directions to form a pressure measuring chamber 13.

[0026] The second sealing element 3 passes through and communicates with the first pipe 1. The second sealing element 3 is adapted to pass through the borehole 12 and is along the length direction of the first pipe 1 (e.g., the first sealing element 2). Figure 1 The holes are spaced apart (as shown in the left-right direction) so that the first pipe 1 can inject grout into the second seal 3 to cause the second seal 3 to expand and seal the borehole 12. Specifically, as shown in the figure... Figure 1 As shown, the second seal 3 passes through the first pipe 1 and is located on the right side of the first seal 2. The first pipe 1 and the second seal 3 are connected so that the first pipe 1 injects grout into the second seal 3, causing the second seal 3 to expand to seal the borehole 12. The left end face of the first seal 2, the right end face of the second seal 3, and the inner circumferential surface of the borehole 12 define the sealing cavity 14.

[0027] The second tube 4 has a third end and a fourth end along its length. The third end of the second tube 4 is adapted to pass through and communicate with the pressure measuring chamber 13, and the fourth end of the second tube 4 extends out of the borehole 12. The second tube 4 is adapted to introduce high-pressure gas. Specifically, as shown... Figure 1 As shown, the second pipe 4 is the air inlet pipe, the third end of the second pipe 4 is the left end of the second pipe 4 and is the air outlet of the second pipe 4, the fourth end of the second pipe 4 is the right end of the second pipe 4 and is the air inlet of the second pipe 4, and the air outlet of the second pipe 4 is connected to the pressure measuring chamber 13, so that high-pressure gas can flow into the pressure measuring chamber 13 through the second pipe 4, thereby supplementing the pressure in the pressure measuring chamber 13.

[0028] Since it takes time for the coal seam gas to desorb to its equilibrium pressure after the pressure measuring chamber 13 is sealed by the first sealing element 2, introducing a gas (such as nitrogen) at a certain pressure into the pressure measuring chamber 13 can accelerate the equilibrium process of the gas pressure within the chamber. Furthermore, the gas filling ensures that the gas pressure within the chamber is close to or equal to the gas pressure within the coal seam, thus achieving a stable measurement state more quickly. Secondly, gas filling reduces the uncertainty caused by gas pressure fluctuations within the pressure measuring chamber 13, improving the accuracy of the measurement results. By controlling the gas filling pressure, a relatively stable pressure environment can be maintained within the pressure measuring chamber 13, contributing to more reliable measurement results. Finally, gas filling also helps ensure that changes in gas pressure during the measurement process are due to actual changes within the coal seam, rather than changes in the internal conditions of the pressure measuring chamber 13. This eliminates the influence of external factors on the measurement results, improving the quality of the measurement.

[0029] The detection element 5 is disposed inside the pressure measuring chamber 13, and the detection element 5 is used to detect the pressure inside the pressure measuring chamber 13. Specifically, as shown... Figure 1 As shown, the detection element 5 is a pressure sensor and is located in the pressure measuring chamber 13 to detect the gas pressure in the pressure measuring chamber 13. When the pressure sensor detects that the pressure in the pressure measuring chamber 13 is stable, it indicates that the borehole 12 has high sealing performance.

[0030] The active gas pressure measuring device 100 at the bottom of a directional long borehole has a first state and a second state. In the first state, the first pipe 1 injects grout into the first seal 2 and the second seal 3 to expand the first seal 2 and the second seal 3, thereby sealing the borehole 12. In the second state, when the pressure of one of the first seal 2 and the second seal 3 is higher than a first preset value, the first pipe 1 injects grout into the area between the first seal 2 and the second seal 3 so that the grout fills the crack in the borehole 12 between the first seal 2 and the second seal 3, and the second pipe 4 introduces high-pressure gas into the pressure measuring chamber 13.

[0031] Specifically, such as Figure 1 As shown, in the first state, the first pipe 1 can inject grout into the first seal 2 and the second seal 3 so that the first seal 2 and the second seal 3 expand simultaneously, so that the outer peripheral surfaces of the first seal 2 and the second seal 3 fit into the inner peripheral surfaces of the borehole 12, thereby sealing the borehole 12 simultaneously. In the second state, the first pipe 1 is disconnected from the first seal 2 so that the first pipe 1 can inject grout into the sealing cavity 14, so that the grout fills the sealing cavity 14. Due to the sealing of the first seal 2 and the second seal 3, the grout can fill the crack in the borehole 12 where the sealing cavity 14 is located, so as to prevent the gas in the pressure measuring chamber 13 from flowing out of the borehole 12 through the crack, thus ensuring the stability and accuracy of the detection of the detection element 5.

[0032] The active gas pressure measuring device 100 at the bottom of the directional long borehole of this invention includes a first tube 1, a first sealing element 2, a second sealing element 3, and a detection element 5. The first tube 1, the first sealing element 2, and the second sealing element 3 can seal cracks in the borehole 12, ensuring the sealing of the pressure measuring chamber 13 and the detection results of the detection element 5, reducing gas pressure loss, eliminating the need for a pressure measuring tube, eliminating pressure drop loss of the pressure measuring tube in related technologies, improving the accuracy of the measurement results and achieving real-time reading. The second tube 4 allows gas to be introduced into the pressure measuring chamber 13, reducing the detection time.

[0033] In some embodiments, the active gas pressure measuring device 100 at the bottom of a directional long borehole further includes a first valve 6. The first valve 6 is located on the side of the first seal 2 facing the second seal 3. In a first state, the first end of the first pipe 1 is connected to the first seal 2 through the first valve 6, so that the first pipe 1 injects grout into the first seal 2 through the first valve 6 to cause the first seal 2 to expand. In a second state, the first valve 6 is disconnected from the first seal 2, so that grout fills the space between the first seal 2 and the second seal 3. Specifically, as Figure 1 As shown, the first valve 6 is a one-way pressure relief valve and is located on the right side of the first seal 2. The grouting outlet of the first pipe 1 is connected to the first seal 2 through the first valve 6. In the first working state, the first valve 6 is in normal working state, and the grout can flow into the first seal 2 through the first pipe 1, so that the first seal 2 seals the borehole 12. In the second working state, the pressure inside the first seal 2 reaches the first preset value P1, the first pipe 1 is activated and disconnected from the first seal 2. At this time, the first seal 2 is still in an expanded state, and the outlet of the first pipe 1 is connected to the sealing cavity 14, so that the first pipe 1 grouts the sealing cavity 14, and the grout will flow into the crack of the borehole 12 through the sealing cavity 14.

[0034] In some embodiments, the active gas pressure measuring device 100 at the bottom of a directional long borehole further includes a centralizer 7, which passes through the first pipe 1 and the second pipe 4 and is adapted to be disposed within the borehole 12. The centralizer 7 is located on the side of the second seal 3 away from the first seal 2 and is spaced apart from the second seal 3 along the length direction of the first pipe 1. Specifically, as Figure 1 As shown, the stabilizer 7 can be installed inside the borehole 12. The stabilizer 7 has a first hole and a second hole that penetrate the stabilizer 7 in the left-right direction. The first tube 1 and the second tube 4 pass through the first hole and the second hole respectively and are installed on the stabilizer 7. The stabilizer 7 is located on the right side of the second sealing member 3 and is spaced apart from the second sealing member 3 in the left-right direction. Thus, the stabilizer 7 provides support for the first tube 1 and the second tube 4, which can effectively prevent the wires, the first tube 1 and the borehole wall from being damaged by friction.

[0035] In some embodiments, the number of stabilizers 7 may be multiple, and the multiple stabilizers 7 are spaced apart on the first tube 1 along the length direction of the first tube 1. Thus, the first tube 1 is supported by the multiple stabilizers 7.

[0036] In some embodiments, the active gas pressure measuring device 100 at the bottom of the directional long borehole further includes a third state and a fourth state. In the third state, when the pressure of the grout between the first seal 2 and the second seal 3 is higher than a second preset value, the grout will push the second seal 3 toward the adjacent stabilizer 7 to expand the grouting range. In the fourth state, the second seal 3 abuts against the stabilizer 7 so that when the pressure within the second seal 3 is higher than the third preset value, the first pipe 1 stops grouting. Specifically, as shown... Figure 1 As shown, in the third working state, the grout pressure in the sealing cavity 14 is higher than the second preset value P2. At this time, the pressure in the sealing cavity 14 is higher than the friction between the second sealing element 3 and the inner circumferential surface of the borehole 12, allowing the grout to push the second sealing element 3 to the right. Thus, the sealing cavity 14 can be gradually expanded, ensuring the grouting pressure and grouting quality. In the fourth working state, the second sealing element 3 moves to the left side of the centralizer 7 and abuts against the centralizer 7, continuously grouting the sealing cavity 14. When the grout in the second sealing element 3 is higher than the third preset value P3, the first pipe 1 stops grouting.

[0037] In some embodiments, the active gas pressure measuring device 100 at the bottom of a directional long borehole further includes a second valve 8, which is disposed on the second seal 3. In the first, second, and third states, the first pipe 1 can inject grout into the second seal 3 to cause the second seal 3 to expand. In the fourth state, when the pressure inside the second seal 3 is higher than a third preset value, the second valve 8 is activated to reduce the pressure inside the second seal 3, and the first pipe 1 stops injecting grout into the second seal 3. Specifically, as shown... Figure 1 As shown, the second valve 8 is a one-way valve and is located on and connected to the second seal 3. In the first, second, and third working states, the first pipe 1 injects slurry into the second seal 3 to cause the second seal 3 to expand. In the fourth working state, when the slurry pressure inside the second seal 3 is greater than the third preset value P3, the second valve 8 can be activated to cause a one-way burst, thereby relieving the pressure on the second seal 3 and prompting the operator to stop injecting slurry into the second seal 3, preventing the second seal 3 from being damaged due to excessive slurry pressure, thus ensuring the service life of the second seal 3.

[0038] In some embodiments, the active gas pressure measuring device 100 at the bottom of the directional long borehole also includes an early warning detection element 9.

[0039] The early warning detection element 9 is located at the other end of the first pipe 1 and is adapted to be located outside the borehole 12. The early warning detection element 9 is used to detect the gas concentration and gas pressure outside the borehole 12. When the early warning detection element 9 detects that the gas concentration or gas pressure outside the borehole 12 is higher than a preset value, the early warning detection element 9 issues an alarm. The early warning detection element 9 is connected to the detection element 5, so that when the detection element 5 detects that the pressure drop rate in the pressure measuring chamber 13 is higher than a preset value, the early warning detection element 9 issues an alarm. Specifically, as shown... Figure 1 As shown, the early warning detection element 9 is a data acquisition and early warning device. It can be installed outside the borehole 12 and near its opening. The early warning detection element 9 detects the gas concentration and pressure near the borehole opening. If the gas concentration and pressure at the opening are significantly higher than in other areas of the roadway, it indicates that the borehole 12 is not properly sealed. The early warning detection element 9 will issue an alarm, reminding operators to re-grout and seal the borehole 12. The early warning detection element 9 can be electrically connected to the detection element 5 via a wire. Therefore, if the gas pressure detected by the detection element 5 drops significantly within a short period, it indicates that the borehole 12 is not properly sealed. The early warning detection element 9 will issue an audible and electrical alarm, requiring repeated grouting and sealing of the borehole 12 and replenishment of air to the pressure measuring chamber 13.

[0040] In some embodiments, the active gas pressure measuring device 100 at the bottom of a directional long borehole further includes a high-pressure gas cylinder 10, which is adapted to store high-pressure gas and is connected to the fourth end of the second tube 4, so that the high-pressure gas cylinder 10 supplies gas to the pressure measuring chamber 13 through the second tube 4. Specifically, as Figure 1 As shown, the high-pressure gas is high-pressure nitrogen and is stored in the high-pressure gas cylinder 10. The outlet of the high-pressure gas cylinder 10 is connected to the inlet of the second pipe 4, so that the high-pressure gas cylinder 10 serves as a gas supply source to supply gas to the pressure measuring chamber 13.

[0041] In some embodiments, the active gas pressure measuring device 100 at the bottom of the directional long borehole further includes a grouting pump 11, which is located at and communicates with the second end of the first pipe 1, so that grout is delivered into the first pipe 1 through the grouting pump 11. Specifically, as Figure 1 As shown, the grouting pump 11 is connected to the inlet of the first pipe 1 and is located outside the borehole 12. Thus, the grouting pump 11 continuously delivers grout into the first pipe 1 and flows into the first seal 2, the second seal 3 and the sealing cavity 14 through the first pipe 1.

[0042] In some embodiments, the first sealing element 2 is a packer. Since the packer typically expands first during the grouting process, it contacts the borehole wall of the borehole 12 to form a preliminary seal, which helps establish the basic conditions for the pressure measuring chamber 13 and allows it to withstand a certain pressure without easily moving, thus helping to maintain the sealed state of the pressure measuring chamber 13. Therefore, using a packer as the first sealing element 2 allows for a more reasonable design of the first sealing element 2.

[0043] In some embodiments, the second seal 3 is a pressure-controlled capsule. Because the pressure-controlled capsule can move along the borehole 12 under grouting pressure, it helps to better adapt to the irregular shape of the borehole wall, improving the sealing effect and reducing the risk of gas leakage. Therefore, using a pressure-controlled capsule as the second seal 3 allows for a more rational design of the second seal 3.

[0044] The following is based on Figure 1 Specifically, the active gas pressure measuring device 100 at the bottom of the directional long borehole according to an embodiment of the present invention includes a first pipe 1, a first sealing element 2, a second sealing element 3, a second pipe 4, a detection element 5, a first valve 6, a centralizer 7, a second valve 8, an early warning detection element 9, a high-pressure gas cylinder 10, a grouting pump 11, a tee, a valve, a pressure-resistant hose, and a wire.

[0045] The centralizer 7 has a first through hole and a second through hole. The fourth end of the second tube 4 is connected to a tee. The third end of the second tube 4 passes through the first through hole of the centralizer 7, the side wall of the second seal 3, and the side wall of the first seal 2 in sequence, and finally enters the pressure measuring chamber 13.

[0046] One end of the wire remains outside the borehole of the drill hole 12 and is connected to the early warning detection component 9. The other end of the wire passes through the tee and the second pipe 4 and then extends into the pressure measuring chamber 13. The tee and the wire are assembled in a sealed manner.

[0047] The third outlet of the tee is connected to the high-pressure gas cylinder 10 via a pressure-resistant hose, and a valve is installed on the tee.

[0048] The second end of the first pipe 1 extends out of the borehole and is connected to the grouting pump 11. The first end of the first pipe 1 passes through the second through hole of the stabilizer 7 and is connected to one side of the second seal 3. It extends out from the other side of the second seal 3 and is connected to the first valve 6 and the first seal 2 in sequence.

[0049] The stabilizer 7 serves as a guide for the second tube 4 and the first tube 1, ensuring that they are not damaged due to friction with the borehole wall during and after being fed into the borehole 12. Of course, multiple stabilizers 7 can be set at intervals according to the length of the borehole 12.

[0050] The detection element 5 can monitor the gas pressure in the pressure measuring chamber 13 in real time, and can transmit the pressure measurement data to the early warning detection element 9 outside the borehole through the wire. The gas concentration in the air at the borehole opening can be read through the early warning detection element 9. When the gas concentration in the air at the borehole opening changes abnormally, this device can alarm through the audible and electrical signals of the early warning detection element 9.

[0051] The second pipe 4 passes through the gap between the second seal 3, the first seal 2 and the hole wall of the borehole 12. When the second seal 3 and the first seal 2 are grouted and expanded, the hole wall, the second pipe 4 and the second seal 3 and the first seal 2 can fit tightly together, thus sealing the borehole 12.

[0052] The first pipe 1 is connected to the second sealing element 3 and the first sealing element 2, that is, the slurry can be injected into the second sealing element 3 and the first sealing element 2 through the first pipe 1;

[0053] A first valve 6 is provided between the first pipe 1 and the first sealing element 2. When the grouting pressure reaches the first preset value P1, the first valve 6 is activated and disconnected from the first sealing element 2, and the first sealing element 2 can remain in an expanded and sealed state.

[0054] When the grouting pressure reaches the second preset value P2 and is greater than the frictional resistance P between the second sealing member 3 and the hole wall, the second sealing member 3 will move along the borehole 12 toward the hole opening under the action of the grouting pressure until it is blocked by the centralizer 7 and stops.

[0055] The second sealing element 3 is provided with a second valve 8. When the grouting pressure rises to the burst pressure P3 of the second valve 8, the second valve 8 will burst. At this time, the second sealing element 3 will still remain in an expanded and sealed state.

[0056] The relationship between the three critical pressures during the grouting process is as follows: P1 <P2<P3;

[0057] The high-pressure gas cylinder 10 can be filled with gas at a certain pressure into the pressure measuring chamber 13 to shorten the gas pressure rise and pressure measuring time in the pressure measuring chamber 13. The gas can be, but is not limited to, nitrogen.

[0058] The active method for measuring bottom gas pressure in directional long boreholes according to embodiments of the present invention includes the following steps:

[0059] Using a kilometer drilling rig, construct kilometer-long borehole 12 in line with or across the layer according to the designed parameters. After the construction of borehole 12 is completed, remove the drill rod.

[0060] The various components of the measuring device are pre-connected, and the measuring device is sent into the predetermined position of the borehole 12 using a directional drilling machine. A gap of about 2m is left between the first sealing member 2 and the bottom of the borehole 12 as a pressure measuring chamber 13.

[0061] Connect the first pipe 1 to the grouting pump 11, and use the grouting pump 11 to inject grout into the second sealing element 3 and the first sealing element 2. After the second sealing element 3 and the first sealing element 2 expand, they stick tightly to the hole wall, thus sealing the drill hole 12.

[0062] When the grouting pressure reaches the critical pressure P1 of the first valve 6, the first valve 6 is activated and disconnected from the first seal 2. The first seal 2 remains in an expanded and sealed state. As grouting continues, the grout will fill the borehole 12 between the first seal 2 and the second seal 3 and the cracks in the borehole wall of that section, thereby sealing the gas.

[0063] When the grouting pressure reaches P2 and is greater than the frictional resistance between the second seal 3 and the borehole wall, the second seal 3 will move along the borehole 12 toward the borehole opening under the action of the grouting pressure until it is blocked by the centralizer 7 and stops.

[0064] When the grouting pressure rises to the critical pressure P3 of the second valve 8, the second valve 8 will be activated. At this time, the second seal 3 will still remain in an expanded and sealed state, but the pressure gauge of the grouting pump 11 will show a sudden pressure drop and stop grouting.

[0065] Connect the tee, pressure-resistant hose and high-pressure gas cylinder 10, open the valve and the valve of high-pressure gas cylinder 10 in sequence, inject specific gas into the pressure measuring chamber 13 to the preset pressure according to the set pressure, and close the valve and the valve of high-pressure gas cylinder 10.

[0066] The detection element 5 and the early warning detection element 9 can detect the gas pressure of borehole 12 and the gas concentration in the air at the borehole opening. Observe the gas pressure and gas concentration values ​​displayed by the early warning detection element 9. If the gas pressure drops significantly in a short period of time or the gas concentration in the air at the borehole opening is significantly higher than the gas concentration in other areas of the roadway, it indicates that the borehole 12 is not sealed properly. The early warning detection element 9 will issue an audible and electrical alarm, and the grouting and sealing of borehole 12 and the air replenishment operation need to be repeated.

[0067] Once borehole 12 is properly sealed and gas filling has been completed for a certain period of time (e.g., 24 hours), the gas pressure value of the early warning detection component 9 can be considered as the gas pressure of the coal seam at that point.

[0068] In summary, the technical advantages of the active gas pressure measuring device 100 and measuring method at the bottom of the directional long borehole according to the embodiments of the present invention are as follows:

[0069] This method eliminates the heavy reliance on roadway engineering for gas pressure measurement, and achieves long-distance and accurate measurement of gas pressure in the target coal seam area by "drilling instead of roadway" through directional drilling 12.

[0070] The 12-hole sealing system is highly efficient, and the device can effectively prevent damage caused by friction between the grouting (air) pipe and the hole wall during installation.

[0071] It can eliminate the pressure drop loss of the pressure measuring tube in the traditional pressure measurement method, improve the accuracy of the measurement results and achieve real-time reading;

[0072] Rapid and accurate measurement of coal seam gas pressure over long distances, dynamic monitoring of gas pressure, and efficient leak detection and early warning technologies are achieved.

[0073] The gas pressure measuring device 100 of this invention not only ensures a good seal for the pressure measuring borehole 12, prevents wear along the first pipe 1, and avoids pressure drop loss, but also enables remote pressure measurement and identification and early warning of gas leakage in the borehole 12 even without roadways. This is of significant engineering importance for accurately measuring coal seam gas pressure over long distances, timely understanding coal seam gas parameters, and scientifically guiding the prevention and control of coal mine gas disasters.

[0074] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0075] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0076] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0077] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0078] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0079] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An active device for measuring gas pressure at the bottom of a directional long borehole, characterized in that, include: A first tube having a first end and a second end along its length, one end of the first tube being adapted to be inserted into a borehole, the second end of the first tube extending out of the borehole, and the first tube being adapted to pass through slurry. A first sealing element is disposed at the first end of the first pipe and communicates with the first pipe. The first sealing element is adapted to pass through the borehole so that the first pipe injects grout into the first sealing element to expand the first sealing element to seal the borehole. The first sealing element is spaced apart from the bottom of the borehole to form a pressure measuring chamber. A second sealing element is inserted through and communicates with the first pipe. The second sealing element is adapted to be inserted into the borehole and is spaced apart from the first sealing element along the length of the first pipe, so that the first pipe injects grout into the second sealing element to expand the second sealing element and seal the borehole. The second tube has a third end and a fourth end in its length direction. The third end of the second tube is adapted to pass through the pressure measuring chamber and communicate with the pressure measuring chamber. The fourth end of the second tube extends out of the borehole. The second tube is adapted to introduce high-pressure gas. The detection element is disposed in the pressure measuring chamber and is used to detect the pressure in the pressure measuring chamber. The active gas pressure measuring device at the bottom of the directional long borehole has a first state and a second state. In the first state, the first pipe injects grout into the first seal and the second seal to expand the first seal and the second seal, and the first seal and the second seal seal the borehole. In the second state, when the pressure of one of the first seal and the second seal is higher than a first preset value, the first pipe injects grout into the area between the first seal and the second seal so that the grout fills the crack in the borehole between the first seal and the second seal, and the second pipe introduces high-pressure gas into the pressure measuring chamber. A centralizer is provided, which is inserted through the first pipe and the second pipe and is adapted to be installed inside the borehole. The centralizer is located on the side of the second seal away from the first seal and is spaced apart from the second seal along the length of the first pipe. The active gas pressure measuring device at the bottom of the directional long borehole also includes a third state and a fourth state. In the third state, when the pressure of the slurry between the first seal and the second seal is higher than a second preset value, the slurry will push the second seal to move toward the direction adjacent to the centralizer to expand the grouting range. In the fourth state, the second seal abuts against the centralizer so that when the pressure in the second seal is higher than the third preset value, the grouting of the first pipe stops.

2. The active gas pressure measuring device at the bottom of a directional long borehole according to claim 1, characterized in that, It also includes a first valve, which is located on the side of the first seal facing the second seal. In the first state, the first end of the first pipe is connected to the first seal through the first valve so that the first pipe injects grout into the first seal through the first valve to cause the first seal to expand. In the second state, the first valve is disconnected from the first seal so that the grout fills between the first seal and the second seal.

3. The active gas pressure measuring device at the bottom of a directional long borehole according to claim 1, characterized in that, It also includes a second valve, which is disposed on the second seal. In the first state, the second state, and the third state, the first pipe can inject grout into the second seal to cause the second seal to expand. In the fourth state, when the pressure inside the second seal is higher than a third preset value, the second valve is activated to reduce the pressure inside the second seal, and the first pipe stops injecting grout into the second seal.

4. The active gas pressure measuring device at the bottom of a directional long borehole according to claim 1, characterized in that, It also includes a warning detection device, which is located at the other end of the first pipe and is adapted to be located outside the borehole. The warning detection device is used to detect the gas concentration and gas pressure outside the borehole. When the warning detection device detects that the gas concentration or gas pressure outside the borehole is higher than a preset value, the warning detection device issues an alarm. The warning detection device is connected to the detection device so that when the detection device detects that the pressure drop rate in the pressure measuring chamber is higher than a preset value, the warning detection device issues an alarm.

5. The active gas pressure measuring device at the bottom of a directional long borehole according to claim 1, characterized in that, It also includes a high-pressure gas cylinder, which is adapted to store high-pressure gas and is connected to the fourth end of the second tube so that the high-pressure gas cylinder supplies gas to the pressure measuring chamber through the second tube.

6. The active gas pressure measuring device at the bottom of a directional long borehole according to claim 1, characterized in that, It also includes a grouting pump, which is located at and connected to the second end of the first pipe, so that the grout is delivered into the first pipe by the grouting pump.

7. The active device for measuring bottom gas pressure in directional long boreholes according to claim 1, characterized in that, The first sealing element is a packer, and the second sealing element is a pressure-controlled capsule.

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