Directional long drill hole bottom gas pressure measuring device

Abstract

The invention discloses a directional long drill hole bottom gas pressure measuring device which comprises a first pipe, a first sealing piece, a second sealing piece, a second pipe and a detecting piece, one end of the first pipe is suitable for being arranged in a drill hole in a penetrating mode, and the second end of the first pipe extends out of the drill hole; the first sealing piece is arranged at the first end of the first pipe and communicated with the first pipe, the second sealing piece is arranged on the first pipe in a penetrating mode and communicated with the first pipe, the second sealing piece is suitable for being arranged in a drill hole in a penetrating mode, the second sealing piece and the first sealing piece are arranged in a spaced mode in the length direction of the first pipe, and the third end of the second pipe is suitable for being arranged in a pressure measuring cavity in a penetrating mode and communicated with the pressure measuring cavity. The fourth end of the second pipe extends out of the drill hole, the second pipe is suitable for introducing high-pressure gas, and the detection piece is arranged in the pressure measuring cavity. The directional long drill hole bottom gas pressure measuring device has the advantages of being simple in structure, accurate in measuring result and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine safety, and in particular relates to a device for actively measuring gas pressure at the bottom of a directional long borehole. Background Art

[0002] Coal seam gas pressure is the force generated by the free thermal motion and collision of gas molecules in the pores of coal seams. When other conditions are the same, the greater the coal seam gas pressure, the greater the gas content of coal, the danger of coal and gas outburst, and the gas outburst volume during coal seam mining. Therefore, the coal seam gas pressure index is the main basis for the identification, prediction, extraction design, and outburst elimination effect inspection of coal and gas outburst danger.

[0003] In the related technology, the coal seam gas pressure in coal mines is measured by short boreholes. After the borehole construction is completed, the borehole is flushed and the drill rod is withdrawn. The pressure measuring tube is inserted into the borehole and sealed to form a closed pressure measuring cavity. The pressure gauge is installed at the outer end of the hole through the connecting vessel principle to read the gas pressure value. The short borehole measurement leads to inaccurate test results and long measurement time. Summary of the invention

[0004] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0005] In the related art, there are several problems in the coal seam gas pressure measurement method: (1) Due to the relatively loose structure of the coal seam or the large number of cracks generated by the coal and rock layers due to the tunnel excavation, the sealing hole is not tight, and the gas pressure measurement is distorted; (2) The sealing hole grouting pipe is easily rubbed against the hole wall when it is transported along the borehole, causing the grouting pipe to be damaged 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 along the pressure measuring tube to the hole mouth, resulting in a smaller measurement result; (4) Due to the limitations of coal and rock tunnel engineering and ordinary drilling construction technology, the ordinary drilling pressure measurement method cannot achieve long-distance coal and rock tunnel engineering. (5) In the related technologies, the pressure measurement method lacks rapid identification technology in the pressure measurement leakage verification; (6) The pressure measurement method has a short gas pressure measurement distance and is heavily dependent on the pressure measurement of tunnel engineering, which cannot accurately test the coal seam gas pressure over long distances; (7) The position of the grouting pipe and the conductor along the pressure measurement method cannot be controlled, and the grouting pipe and the conductor are easily damaged by friction with the hole wall; (8) The pressure measurement tube of 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 system leakage during the pressure measurement process and issue an early warning.

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

[0007] To this end, an embodiment of the present invention provides a device for measuring the gas pressure at the bottom of a directional long borehole with accurate measurement results and short measurement time.

[0008] According to an embodiment of the present invention, a gas pressure measuring device at the bottom of a directional long borehole comprises: a first tube, the first tube having a first end and a second end in the length direction thereof, one end of the first tube being suitable for being inserted into the borehole, the second end of the first tube extending out of the borehole, and the first tube being suitable for passing slurry; a first sealing member, the first sealing member being arranged at the first end of the first tube and being communicated with the first tube, the first sealing member being suitable for being inserted into the borehole, so that the first tube injects grout into the first sealing member so that the first sealing member expands to seal the borehole, and the first sealing member is spaced apart from the bottom of the borehole to form a pressure measuring chamber; a second sealing member, the second sealing member being inserted into the first tube and being communicated with the first tube, the second sealing member being suitable for being inserted into the borehole and being spaced apart from the first sealing member along the length direction of the first tube, so that the first tube injects grout into the second sealing member so that the second sealing member expands to seal the borehole; a second tube, the second tube being spaced apart from the first seal member along the length direction thereof It has a third end and a fourth end upward, the third end of the second tube is suitable for being inserted into the pressure measuring chamber and connected with the pressure measuring chamber, the fourth end of the second tube extends out of the borehole, and the second tube is suitable for passing high-pressure gas; a detection component, the detection component is arranged in the pressure measuring chamber, and the detection component is used to detect the pressure in the pressure measuring chamber. The directional long borehole bottom gas pressure measuring device has a first state and a second state. In the first state, the first tube grouts the first seal and the second seal to expand the first seal and the second seal, and the first seal and the second seal block 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 tube grouts the area between the first seal and the second seal so that the slurry fills the crack in the borehole between the first seal and the second seal, and the second tube passes high-pressure gas to the pressure measuring chamber.

[0009] The gas pressure measuring device of the embodiment of the present invention is provided with a grouting pipe, a first sealing member, a second sealing member, a detection member and a second pipe, which can seal the cracks in the borehole, ensure the sealing of the pressure measuring chamber and the detection result of the detection member, reduce the pressure loss of the gas, improve the accuracy of the measurement result and realize the real-time reading.

[0010] In some embodiments, the directional long borehole bottom gas pressure measuring device also includes a first valve, which is arranged on the side of the first seal facing the second seal. In the first state, the first end of the first tube is connected to the first seal through the first valve, so that the first tube 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 slurry is filled between the first seal and the second seal.

[0011] In some embodiments, the directional long borehole bottom gas pressure measuring device also includes a stabilizer, which is passed through the first tube and the second tube and is suitable for being arranged in 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 tube.

[0012] In some embodiments, the directional long borehole bottom gas pressure measuring device 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 stabilizer to expand the grouting range. In the fourth state, the second seal is offset from the stabilizer 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 directional long borehole bottom gas pressure measuring device also includes a second valve, which is arranged on the second seal. In the first state, the second state and the third state, the first tube can inject grout into the second seal to expand the second seal. In the fourth state, when the pressure in the second seal is higher than the third preset value, the second valve is activated to reduce the pressure in the second seal, and the first tube stops injecting grout into the second seal.

[0014] In some embodiments, the directional long borehole bottom gas pressure measuring device also includes an early warning detection component, which is arranged at the other end of the first tube and is suitable for being arranged outside the borehole, and the early warning detection component is used to detect the gas concentration outside the borehole and the gas pressure outside the borehole, so that when the early warning detection component detects that the gas concentration outside the borehole or the gas pressure outside the borehole is higher than a preset value, the early warning detection component sends out an alarm, and the early warning detection component is connected to the detection component, so that when the detection component detects that the pressure drop rate in the pressure measuring chamber is higher than a preset value, the early warning detection component sends out an alarm.

[0015] In some embodiments, the directional long borehole bottom gas pressure measuring device also includes a high-pressure gas cylinder, which is suitable for storing 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 directional long borehole bottom gas pressure measuring device also includes a grouting pump, which is arranged at the second end of the first pipe and connected to the second end of the first pipe, so that the slurry is transported 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. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0019] A device for measuring gas pressure at the bottom of a directional long borehole 100;

[0020] The first tube 1; the first sealing member 2; the second sealing member 3; the second tube 4; the detection member 5; the first valve 6; the centralizer 7; the second valve 8; the early warning detection member 9; the high-pressure gas cylinder 10; the grouting pump 11; the borehole 12; the pressure measuring chamber 13; and the sealing chamber 14. DETAILED DESCRIPTION

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

[0022] The following describes a device for measuring gas pressure at the bottom of a directional long borehole according to an embodiment of the present invention with reference to the accompanying drawings.

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

[0024] The first tube 1 is in its length direction (such as Figure 1 The first tube 1 has a first end and a second end in the left-right direction (shown in FIG. 1 ), one end of the first tube 1 is suitable for being inserted into the borehole 12, and the second end of the first tube 1 extends out of the borehole 12, and the first tube 1 is suitable for passing slurry. Specifically, as Figure 1 As shown, the first tube 1 is a grouting tube, the first end of the first tube 1 is a grouting outlet, the second end of the first tube 1 is a grouting inlet, and the first tube 1 can be inserted into the borehole 12 so that grouting is performed on the borehole 12 through the first tube 1.

[0025] The first sealing member 2 is disposed at the first end of the first pipe 1 and is in communication with the first pipe 1. The first sealing member 2 is adapted to be inserted into the borehole 12 so that the first pipe 1 injects grout into the first sealing member 2 to expand the first sealing member 2 to seal the borehole 12. The first sealing member 2 is spaced apart from the bottom of the borehole 12 to form a pressure measuring chamber 13. Specifically, Figure 1 As shown, the first seal 2 is arranged at the left end of the first tube 1 and is connected to the grouting outlet of the first tube 1. Grouting can be performed on the first seal 2 to expand the first seal 2 so that the outer circumference of the first seal 2 fits with the inner circumference of the borehole 12, so that the first seal 2 seals the borehole 12, and the first seal 2 and the bottom of the borehole 12 (such as Figure 1 The left end surface of the borehole 12 shown in the figure is arranged at intervals along the left-right direction to form a pressure measuring cavity 13.

[0026] The second sealing member 3 is disposed on the first tube 1 and communicated with the first tube 1. The second sealing member 3 is adapted to be disposed in the borehole 12 and communicate with the first sealing member 2 along the length direction of the first tube 1 (eg Figure 1 The first pipe 1 is arranged at intervals in the left and right directions as shown, so that the first pipe 1 injects grout into the second sealing member 3 to expand the second sealing member 3 to seal the borehole 12. Specifically, as Figure 1 As shown, the second seal 3 is passed through the first tube 1 and is arranged on the right side of the first seal 2. The first tube 1 and the second seal 3 are connected so that the first tube 1 can grout the second seal 3, so that the second seal 3 expands 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 a sealing cavity 14.

[0027] The second tube 4 has a third end and a fourth end in its length direction. The third end of the second tube 4 is suitable for being inserted into and connected to the pressure measuring cavity 13. The fourth end of the second tube 4 extends out of the borehole 12. The second tube 4 is suitable for passing high-pressure gas. Specifically, Figure 1 As shown, the second tube 4 is an air inlet pipe, the third end of the second tube 4 is the left end of the second tube 4 and the air outlet of the second tube 4, the fourth end of the second tube 4 is the right end of the second tube 4 and the air inlet of the second tube 4, and the air outlet of the second tube 4 is connected to the pressure measuring chamber 13, so that the high-pressure gas can flow into the pressure measuring chamber 13 through the second tube 4, thereby replenishing the pressure in the pressure measuring chamber 13.

[0028] Since, after the pressure measuring chamber 13 is blocked by the first seal 2, it takes a certain amount of time for the coal gas to desorb to the equilibrium pressure, therefore, by filling the pressure measuring chamber 13 with a certain pressure of gas (such as nitrogen), the equilibrium process of the gas pressure in the pressure measuring chamber 13 can be accelerated, and the inflation makes the pressure of the gas in the pressure measuring chamber 13 close to or equal to the gas pressure in the coal seam, so as to reach a stable measurement state more quickly. Secondly, inflation can reduce the uncertainty caused by the gas pressure fluctuation in the pressure measuring chamber 13 and improve the accuracy of the measurement results. By controlling the inflation pressure, it can ensure that a relatively stable pressure environment is always maintained in the pressure measuring chamber 13, which helps to obtain more reliable measurement results. Finally, inflation also helps to ensure that the change in gas pressure during the measurement process is due to the real change inside the coal seam, rather than due to the change in the internal conditions of the pressure measuring chamber 13. In this way, the influence of external factors on the measurement results can be eliminated and the quality of the measurement can be improved.

[0029] The detection member 5 is disposed in the pressure measuring chamber 13, and the detection member 5 is used to detect the pressure in the pressure measuring chamber 13. Specifically, Figure 1 As shown, the detection member 5 is a pressure sensor and is arranged 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 can be explained that the sealing performance of the borehole 12 is high.

[0030] The directional long borehole bottom gas pressure measuring device 100 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, and the first seal 2 and the second seal 3 block 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 slurry fills the crack in the borehole 12 between the first seal 2 and the second seal 3, and the second pipe 4 passes high-pressure gas into the pressure measuring chamber 13.

[0031] Specifically, Figure 1 As shown, in the first state, the first tube 1 can perform grouting on the first seal 2 and the second seal 3 to make the first seal 2 and the second seal 3 expand simultaneously so that the outer peripheral surface of the first seal 2 and the outer peripheral surface of the second seal 3 fit with the inner peripheral surface of the borehole 12, so that the first seal 2 and the second seal 3 can simultaneously block the borehole 12. In the second state, the first tube 1 is disconnected from the first seal 2 so that the first tube 1 performs grouting on the sealing cavity 14 so that the slurry is filled in the sealing cavity 14. Due to the blocking of the first seal 2 and the second seal 3, the slurry can be filled in the cracks of the borehole 12 where the sealing cavity 14 is located, so as to prevent the gas in the pressure measuring cavity 13 from flowing out of the borehole 12 through the cracks, thereby ensuring the stability and accuracy of the detection of the detection member 5.

[0032] The device 100 for measuring gas pressure at the bottom of a directional long borehole according to an embodiment of the present invention is provided with a first tube 1, a first seal 2, a second seal 3 and a detection component 5. The first tube 1, the first seal 2 and the second seal 3 can be used to seal cracks in the borehole 12, thereby ensuring the sealing of the pressure measuring chamber 13 and the detection result of the detection component 5, reducing the pressure loss of the gas, eliminating the need to set a pressure measuring tube, eliminating the pressure drop loss of the pressure measuring tube in the pressure measuring method in the related technology, improving the accuracy of the measurement result and realizing the real-time reading. The second tube 4 is provided to pass gas into the pressure measuring chamber 13, thereby reducing the detection time.

[0033] In some embodiments, the directional long borehole bottom gas pressure measuring device 100 further includes a first valve 6, which is disposed 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 expand the first seal 2. In a second state, the first valve 6 is disconnected from the first seal 2, so that the slurry is filled 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 arranged 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 a normal working state, and the slurry can flow into the first seal 2 through the first pipe 1, so that the first seal 2 blocks the borehole 12. In the second working state, at this time, the pressure in the first seal 2 reaches the first preset value P1, the first pipe 1 is started 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 performs grouting on the sealing cavity 14, and the slurry will flow into the crack of the borehole 12 through the sealing cavity 14.

[0034] In some embodiments, the directional long borehole bottom gas pressure measuring device 100 further includes a centralizer 7, which is arranged on the first pipe 1 and the second pipe 4 and is suitable for being arranged in the borehole 12. The centralizer 7 is located on the side of the second sealing member 3 away from the first sealing member 2 and is spaced apart from the second sealing member 3 along the length direction of the first pipe 1. Specifically, as Figure 1 As shown, the centralizer 7 can be arranged in the borehole 12, and the centralizer 7 is provided with a first hole and a second hole penetrating the centralizer 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 arranged on the centralizer 7, and the centralizer 7 is located on the right side of the second seal 3 and is spaced apart from the second seal 3 in the left-right direction. Therefore, the centralizer 7 supports the first tube 1 and the second tube 4, which can effectively avoid damage caused by friction between the conductor, the first tube 1 and the hole wall.

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

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

[0037] In some embodiments, the directional long borehole bottom gas pressure measuring device 100 further includes a second valve 8, which is disposed on the second seal 3. In the first state, the second state, and the third state, the first pipe 1 can inject grout into the second seal 3 to expand the second seal 3. In the fourth state, when the pressure in the second seal 3 is higher than the third preset value, the second valve 8 is activated to reduce the pressure in the second seal 3, and the first pipe 1 stops injecting grout into the second seal 3. Specifically, Figure 1 As shown, the second valve 8 is a one-way valve and is arranged on the second seal 3 and is connected to the second seal 3. In the first working state, the second working state and the third working state, the first tube 1 injects slurry into the second seal 3 to expand the second seal 3. In the fourth working state, when the slurry pressure in the second seal 3 is greater than the third preset value P3, the second valve 8 can be started to cause a one-way explosion, so that the second valve 8 can relieve the pressure on the second seal 3 and can prompt the operator to stop grouting the second seal 3, so as to prevent the second seal 3 from being subjected to excessive slurry pressure, resulting in damage to the second seal 3, thereby ensuring the service life of the second seal 3.

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

[0039] The early warning detection member 9 is arranged at the other end of the first tube 1 and is suitable for being arranged outside the borehole 12. The early warning detection member 9 is used to detect the gas concentration and the gas pressure outside the borehole 12, so that when the early warning detection member 9 detects that the gas concentration or the gas pressure outside the borehole 12 is higher than a preset value, the early warning detection member 9 issues an alarm. The early warning detection member 9 is connected to the detection member 5, so that when the detection member 5 detects that the pressure drop speed in the pressure measuring chamber 13 is higher than a preset value, the early warning detection member 9 issues an alarm. Specifically, as Figure 1 As shown, the early warning detection element 9 is a data acquisition and early warning device. The early warning detection element 9 can be set outside the borehole 12 and near the orifice of the borehole 12. Thus, the gas concentration near the orifice of the borehole 12 and the gas pressure near the orifice of the borehole 12 are detected by the early warning detection element 9. When the gas concentration and gas pressure in the air at the orifice are significantly higher than the gas concentration in other areas of the tunnel, it means that the borehole 12 is not tightly sealed. The early warning detection element 9 issues an alarm to remind the operator that the borehole 12 needs to be re-grouted and sealed. The early warning detection element 9 can be electrically connected to the detection element 5 through a wire. Thus, when the gas pressure detected by the detection element 5 drops significantly in a short period of time, it means that the borehole 12 is not tightly sealed. The early warning detection element 9 will issue an acoustic and electrical alarm, and it is necessary to repeat the grouting and sealing of the borehole 12 and to perform air replenishment operations on the pressure measuring chamber 13.

[0040] In some embodiments, the directional long borehole bottom gas pressure measuring device 100 further includes a high-pressure gas cylinder 10, which is suitable for storing 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, Figure 1 As shown, the high-pressure gas is high-pressure nitrogen and is stored in a high-pressure gas cylinder 10 , and the outlet of the high-pressure gas cylinder 10 is connected to the inlet of the second tube 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 directional long borehole bottom gas pressure measuring device 100 further includes a grouting pump 11, which is disposed at the second end of the first pipe 1 and communicated with the second end of the first pipe 1, so that the slurry is transported into the first pipe 1 through the grouting pump 11. Specifically, 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 , whereby the slurry is continuously transported to the first pipe 1 through the grouting pump 11 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 seal 2 is a packer. Since the packer usually expands first during the grouting process and contacts the borehole wall of the borehole 12 to form a preliminary seal, it helps to establish the basic conditions of the pressure measuring chamber 13 and can withstand a certain pressure without moving easily, which helps to maintain the sealing state of the pressure measuring chamber 13. Therefore, the first seal 2 is a packer, which can make the first seal 2 more reasonably set.

[0043] In some embodiments, the second sealing member 3 is a pressure-controlled capsule. Since the pressure-controlled capsule can move along the borehole 12 under the action of the grouting pressure, it helps to better adapt to the irregular shape of the borehole wall, improve the sealing effect, and reduce the risk of gas leakage. Therefore, the second sealing member 3 is a pressure-controlled capsule, which can make the second sealing member 3 more reasonably set.

[0044] According to the following Figure 1 Specifically describing the gas pressure measuring device 100 at the bottom of a directional long borehole according to the embodiment of the present invention, the device comprises a first pipe 1, a first sealing member 2, a second sealing member 3, a second pipe 4, a detection member 5, a first valve 6, a centralizer 7, a second valve 8, an early warning detection member 9, a high-pressure gas cylinder 10, a grouting pump 11, a tee, a valve, a pressure-resistant hose, and a conductor;

[0045] The centralizer 7 is provided with a first through hole and a second through hole, the fourth end of the second tube 4 is connected to the tee, and the third end of the second tube 4 sequentially 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, and finally penetrates into the pressure measuring chamber 13;

[0046] One end of the wire is left outside the borehole 12 and connected to the early warning detection member 9, and the other end of the wire passes through the tee and the second tube 4 and then goes deep into the pressure measuring cavity 13. The tee and the wire are sealed and assembled;

[0047] The third outlet of the tee is connected to the high-pressure gas cylinder 10 through 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 centralizer 7 and is connected to one side of the second seal 3. The first end of the first pipe 1 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 centralizer 7 guides the second tube 4 and the first tube 1 to ensure that they are not damaged by friction with the hole wall during and after being put into the borehole 12. Of course, multiple centralizers 7 can be arranged at intervals according to the length of the borehole 12.

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

[0051] The second tube 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 tube 4, the second seal 3 and the first seal 2 can fit tightly together to seal the borehole 12.

[0052] The first pipe 1 is connected with the second sealing member 3 and the first sealing member 2, that is, the slurry can be injected from the first pipe 1 into the second sealing member 3 and the first sealing member 2;

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

[0054] When the grouting pressure reaches the second preset value P2 and is greater than the friction 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 mouth under the action of the grouting pressure until it is stopped by the centralizer 7;

[0055] The second sealing member 3 is provided with a second valve 8. When the grouting pressure rises to the bursting pressure P3 of the second valve 8, the second valve 8 will burst, and at this time the second sealing member 3 still maintains an expanded and blocked state;

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

[0057] The high pressure gas cylinder 10 can fill the pressure measuring chamber 13 with gas of a certain pressure to shorten the gas pressure recovery and pressure measuring time of the pressure measuring chamber 13. The gas used can be but is not limited to nitrogen.

[0058] The method for actively measuring gas pressure at the bottom of a directional long borehole according to an embodiment of the present invention comprises the following steps:

[0059] Use a kilometer drilling rig to construct a kilometer borehole 12 along or through the layer according to the designed parameters, and withdraw the drill rod after the construction of the borehole 12 is completed;

[0060] The components of the measuring device are pre-connected, and the measuring device is sent to a predetermined position of the borehole 12 by a directional drill, wherein a distance of about 2 m is left between the first sealing member 2 and the bottom of the borehole 12 as a pressure measuring chamber 13;

[0061] The first pipe 1 is connected to the grouting pump 11, and the grouting pump 11 is used to inject slurry into the second seal 3 and the first seal 2. After the second seal 3 and the first seal 2 expand, they are tightly attached to the hole wall to seal the borehole 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 the expanded and blocked state, and the grouting continues. The slurry will fill the borehole 12 and the cracks in the borehole wall between the first seal 2 and the second seal 3, playing the role of blocking gas;

[0063] When the grouting pressure reaches P2 and is greater than the friction resistance 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 stopped by the centralizer 7;

[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 sealing member 3 still maintains the expansion and blocking state, but the pressure gauge of the grouting pump 11 will indicate a sudden drop in pressure, and the grouting will be stopped;

[0065] Connect the three-way, the pressure-resistant hose and the high-pressure gas cylinder 10, open the valve and the valve of the high-pressure gas cylinder 10 in turn, inject a specific gas into the pressure measuring chamber 13 according to the set pressure to the preset pressure, and close the valve and the valve of the high-pressure gas cylinder 10;

[0066] The detection element 5 and the early warning detection element 9 can detect the gas pressure of the borehole 12 and the gas concentration in the air at the orifice. 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 orifice is significantly higher than the gas concentration in other areas of the tunnel, it means that the borehole 12 is not tightly sealed. The early warning detection element 9 will issue an acoustic and electrical alarm, and it is necessary to repeat the grouting and sealing of the borehole 12 and the gas replenishment operation;

[0067] When the borehole 12 is sealed well and the gas is inflated for a certain period of time (such as 24 hours), the gas pressure value of the early warning detection element 9 can be regarded as the gas pressure of the coal seam at that point.

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

[0069] This method gets rid of the heavy reliance of gas pressure measurement on tunnel engineering, and achieves long-distance and accurate measurement of gas pressure in the target coal seam area by directional drilling 12 "drilling instead of tunneling";

[0070] The drilling hole 12 is sealed efficiently, and the damage caused by the friction between the grouting (gas) pipe and the hole wall can be effectively avoided during the installation of the device;

[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 realize the real-time reading;

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

[0073] The gas pressure measuring device 100 of the embodiment of the present invention can not only achieve good sealing of the pressure measuring borehole 12, prevent wear along the first pipe 1, and avoid pressure drop loss of gas pressure, but also can achieve long-distance pressure measurement without tunnels and identification and early warning of gas leakage in the borehole 12. This has important engineering significance for accurately measuring coal seam gas pressure at a long distance, timely grasping coal seam gas parameters, and scientifically guiding the prevention and control of coal mine gas disasters.

[0074] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0075] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0076] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0077] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0078] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0079] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A device for measuring gas pressure at the bottom of a directional long borehole, characterized in that: include: A first tube, wherein the first tube has a first end and a second end in the length direction thereof, one end of the first tube is suitable for being inserted into the borehole, the second end of the first tube extends out of the borehole, and the first tube is suitable for passing slurry; a first sealing member, the first sealing member being arranged at a first end of the first tube and being in communication with the first tube, the first sealing member being adapted to be inserted into the borehole so that the first tube grouts the first sealing member to expand the first sealing member to 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, the second sealing member being disposed on the first pipe and in communication with the first pipe, the second sealing member being adapted to be disposed in the borehole and being spaced apart from the first sealing member along the length direction of the first pipe, so that the first pipe grouts the second sealing member to expand the second sealing member to seal the borehole; a second tube, the second tube having a third end and a fourth end in the length direction thereof, the third end of the second tube being adapted to be inserted into the pressure measuring cavity and communicated with the pressure measuring cavity, the fourth end of the second tube extending out of the borehole, and the second tube being adapted to be passed with high-pressure gas; A detection member is arranged in the pressure measuring chamber, and the detection member is used to detect the pressure in the pressure measuring chamber. The directional long borehole bottom gas pressure measuring device has a first state and a second state. In the first state, the first tube performs grouting on the first seal and the second seal to expand the first seal and the second seal, and the first seal and the second seal block 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 tube performs grouting on the area between the first seal and the second seal so that the slurry fills the crack in the borehole between the first seal and the second seal, and the second tube passes high-pressure gas into the pressure measuring chamber.

2. The device for measuring gas pressure at the bottom of a directional long borehole according to claim 1, characterized in that: It also includes a first valve, which is arranged on the side of the first seal facing the second seal. In the first state, the first end of the first tube is connected to the first seal through the first valve, so that the first tube 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 slurry is filled between the first seal and the second seal.

3. The device for measuring gas pressure at the bottom of a directional long borehole according to claim 1, characterized in that: It also includes a centralizer, which is inserted into the first pipe and the second pipe and is suitable for being arranged in the borehole. The centralizer is located on a 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.

4. The device for measuring gas pressure at the bottom of a directional long borehole according to claim 3, characterized in that: The directional long borehole bottom gas pressure measuring device 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 stabilizer to expand the grouting range. In the fourth state, the second seal is offset from the stabilizer so that the first pipe stops grouting when the pressure in the second seal is higher than the third preset value.

5. The device for measuring gas pressure at the bottom of a directional long borehole according to claim 4, characterized in that: It also includes a second valve, which is arranged on the second seal. In the first state, the second state and the third state, the first tube can inject grout into the second seal to expand the second seal. In the fourth state, when the pressure in the second seal is higher than a third preset value, the second valve is activated to reduce the pressure in the second seal, and the first tube stops injecting grout into the second seal.

6. The device for measuring gas pressure at the bottom of a directional long borehole according to claim 1, characterized in that: It also includes an early warning detection component, which is arranged at the other end of the first tube and is suitable for being arranged outside the borehole. The early warning detection component is used to detect the gas concentration outside the borehole and the gas pressure outside the borehole, so that when the early warning detection component detects that the gas concentration outside the borehole or the gas pressure outside the borehole is higher than a preset value, the early warning detection component sends out an alarm. The early warning detection component is connected to the detection component, so that when the detection component detects that the pressure drop rate in the pressure measuring chamber is higher than a preset value, the early warning detection component sends out an alarm.

7. The device for measuring gas pressure 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 suitable for storing 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 cavity through the second tube.

8. The device for measuring gas pressure at the bottom of a directional long borehole according to claim 1, characterized in that: It also includes a grouting pump, which is arranged at the second end of the first tube and communicated with the second end of the first tube, so that the slurry is transported into the first tube through the grouting pump.

9. The device for measuring gas pressure at the bottom of a directional long borehole according to claim 1, characterized in that: The first sealing member is a packer, and the second sealing member is a pressure-controlled capsule.

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