A deep-hole gas pressure fixed-point measurement system and its measurement method

Abstract

The present invention discloses a deep-hole gas pressure fixed-point measurement system and a measurement method thereof. The measurement system includes a hole-sealing pressure measurement assembly and a positioning and supporting assembly, and the positioning and supporting assembly is connected to the hole-sealing pressure measurement assembly; the measurement method includes the following steps: S1, complete the construction of the directional pressure measurement borehole; S2, push the positioning and supporting assembly into the borehole; S3, slowly withdraw the drill pipe for the first time to achieve support and positioning between the positioning and supporting assembly and the borehole; S4, slowly withdraw the drill pipe again until it is completely withdrawn from the borehole, so that the support pipe and the steel wire rope form a fixed pulley structure in the deep part of the borehole; S5, cut off the connection between one end of the steel wire rope and the reducer, and reconnect and fix it to one end of the pressure measurement pipe, and lower the pressure measurement pipe and the grouting hole-sealing mechanism to the pressure measurement and plugging position in the borehole by pulling the steel wire rope; S6, grout and inject mucus into the hole-sealing pipeline outside the borehole to complete the sealing of the borehole; S7, install a pressure measurement instrument at the outer end of the pressure measurement pipe to observe the gas pressure.

Description

Technical Field

[0001] The present invention relates to the field of coal mine gas pressure measurement, and particularly to a deep-hole gas pressure fixed-point measurement system and a measurement method thereof. Background Art

[0002] Coal seam gas pressure is an important index for judging the size of coal seam outburst risk and evaluating the effect of gas control. At present, the direct measurement of underground coal seam gas pressure mainly adopts the rubber ring (capsule) mucilage sealing method and the "two-block-one-injection" sealing method. A multi-section hard short pipe connected by threads or a soft long through pipe is used as the pressure measurement pipeline to lead the gas in the hole inside the sealing position to the outside of the drill hole for pressure measurement. This method is generally applicable to drill holes with a sealing depth of less than 20m. With the development and popularization of directional drilling rig equipment, the construction of directional long drill holes for large-area gas control has become an important development direction for mine gas control. Correspondingly, the fixed-point measurement technology for deep-hole gas parameters is still in the research and development stage. In particular, the fixed-point measurement technology for gas pressure in hundreds of meters deep holes is basically blank. The main reason is that the existing deep-hole sealing technology applicable to coal seam gas pressure measurement has not achieved a breakthrough. In the actual on-site application process, the existing rubber ring (capsule) mucilage sealing method and the "two-block-one-injection" sealing method cannot push the soft pressure measurement pipe to the deep part of the drill hole, so the sealing and pressure measurement operation in the deep part of the drill hole cannot be realized, and it is necessary to improve it. Summary of the Invention

[0003] The purpose of the present invention is to provide a deep-hole gas pressure fixed-point measurement system and a measurement method thereof with simple structure and convenient operation for the above problems.

[0004] In order to achieve the above purpose, the technical solution of the present invention is:

[0005] A deep-hole gas pressure fixed-point measurement system includes a sealing and pressure measurement assembly and a positioning and supporting assembly. The positioning and supporting assembly is connected to the sealing and pressure measurement assembly; the sealing and pressure measurement assembly includes a grouting and sealing mechanism, a gas measurement mechanism, and a constant pressure supply mechanism. The constant pressure supply mechanism is arranged outside the drill hole and is connected to the grouting and sealing mechanism arranged in the drill hole; the positioning and supporting assembly is located inside the drill hole. The gas measurement mechanism passes through the grouting and sealing mechanism from the outside of the drill hole and is connected to the positioning and supporting assembly; the positioning and supporting assembly includes a steel wire rope, a clamping mechanism, and a limiting mechanism. The clamping mechanism is clamped to the inner wall of the drill hole through the limiting mechanism, and one end of the steel wire rope bypasses the clamping mechanism and is connected to the gas measurement mechanism.

[0006] Furthermore, the clamping mechanism includes a support pipe and a diameter-changing part. The support pipe is a circular pipe. One end of the support pipe is sealed. A plurality of air inlet holes are arranged on one side wall of the sealed end of the support pipe. The other end of the support pipe is open, and the open end of the support pipe is connected with the diameter-changing part. One end of the diameter-changing part is slidably sleeved in the support pipe and is key-connected with the support pipe. The other end of the diameter-changing part is threadedly connected with the drill rod end. A first connecting part is arranged inside the middle of the support pipe. A wire groove is arranged on the side wall of the support pipe. One end of the steel wire rope is connected with a second connecting part arranged at the end of the diameter-changing part. The other end of the steel wire rope passes around the first connecting part and then passes out of the drill hole through the wire groove on the side wall of the support pipe; when the steel wire rope is connected with the gas detection mechanism, the steel wire rope is disconnected from the second connecting part and connected with the gas detection mechanism.

[0007] Furthermore, the limiting mechanism includes a flexible telescopic strip and a movable ring; the flexible telescopic strip and the movable ring are both sleeved outside the middle of the support pipe. One end of the flexible telescopic strip close to the sealed end of the support pipe is fixedly connected with the outer side wall of the support pipe. One end of the flexible telescopic strip close to the open end of the support pipe is fixedly connected with the movable ring. The movable ring is slidably connected with the support pipe and can slide along the axial direction of the support pipe.

[0008] Furthermore, the grouting hole sealing mechanism includes a grouting pipe and two groups of bag hole sealing units. The two groups of bag hole sealing units are arranged in sequence along the axis direction of the drill hole. Each group of bag hole sealing units includes two bags. The two bags are arranged in sequence along the axis direction of the drill hole. The grouting pipe passes through the four bags in the two groups of bag hole sealing units in sequence. One end of the grouting pipe is sealed. The other end of the grouting pipe is communicated with a grouting device; four first grouting ports are arranged on the outer side wall of the grouting pipe. The four first grouting ports are respectively located in the four bags, and check valves are arranged in the first grouting ports; two second grouting ports are arranged on the outer side wall of the grouting pipe. The two second grouting ports are respectively located between the two bags in the two groups of bag hole sealing units, and blasting valves are arranged in the second grouting ports.

[0009] Furthermore, the constant pressure supply mechanism includes a liquid inlet pipe, a liquid return pipe, a high-pressure gas source bottle, and a mucus tank. One ends of the liquid inlet pipe and the liquid return pipe are located between the two groups of bag hole sealing units. The other ends of the liquid inlet pipe and the liquid return pipe pass through one group of bag hole sealing units and then extend out of the drill hole. A control valve is arranged at the end of the liquid return pipe extending out of the drill hole. The end of the liquid inlet pipe extending out of the drill hole extends to the bottom end of the mucus tank. The top end of the mucus tank is connected with the high-pressure gas source bottle through a pipeline.

[0010] Furthermore, the gas detection mechanism includes a pressure measuring pipe and a pressure measuring instrument. One end of the pressure measuring pipe is connected with the pressure measuring instrument located outside the drill hole. The other end of the pressure measuring pipe passes through the four bags in sequence and is connected with one end of the steel wire rope.

[0011] A measuring method for a fixed-point gas pressure measuring system in deep holes, comprising the following steps:

[0012] S1. Complete the construction of the directional pressure measuring borehole according to the design, accurately record the borehole depth L0 and the surrounding rock lithology characteristics during the borehole construction process, and determine the borehole sealing depth L1 in combination with the borehole depth L0 and the surrounding rock lithology characteristics;

[0013] S2. Install the variable-diameter part in the clamping mechanism at the front end of the drill pipe, slowly push the clamping mechanism to the inner end of the borehole sealing position by using the drill pipe, and at the same time slowly extend the steel wire rope so that it extends synchronously with the clamping mechanism in the borehole, and record the pushing depth L2 of the clamping mechanism;

[0014] S3. Slowly withdraw the drill pipe for the first time, keep the part of the steel wire rope outside the borehole fixed, the support pipe and the variable-diameter part in the clamping mechanism move outwards with the drill pipe, the movable ring in the limiting mechanism slides and squeezes the flexible telescopic strip, and the outer side of the flexible telescopic strip abuts against the inner wall of the borehole, so that the support pipe and the borehole are supported and positioned;

[0015] S4. Slowly withdraw the drill pipe again until it is completely withdrawn from the borehole, and at the same time slowly extend the steel wire rope so that it retreats synchronously with the variable-diameter part in the borehole. After the variable-diameter part exits the borehole, the support pipe and the steel wire rope form a fixed pulley structure in the deep part of the borehole;

[0016] S5. Cut off the connection between one end of the steel wire rope and the variable-diameter part, and reconnect and fix it to one end of the pressure measuring pipe in the gas measuring mechanism. Lower the pressure measuring pipe and the grouting and sealing mechanism to the pressure measuring and plugging position in the borehole by pulling the other end of the steel wire rope. The lowering depth of the pressure measuring pipe is the borehole sealing depth L1;

[0017] S6. Outside the borehole, use the grouting equipment to pump cement slurry into the grouting pipe in the grouting and sealing mechanism, and the grouting and sealing mechanism seals the borehole; then use the constant pressure supply mechanism to pump mucus to realize the mucus plugging operation of the borehole, and finally complete the complete sealing of the borehole;

[0018] S7. Install a pressure measuring instrument at the outer end of the pressure measuring pipe, use the pressure measuring instrument to carry out gas pressure observation operations, and regularly record the coal seam gas pressure.

[0019] Furthermore, the pushing depth L2 of the clamping mechanism is greater than the borehole sealing depth L1 by no less than 2 m; the length of the steel wire rope is not less than 2 times the borehole depth L0.

[0020] Furthermore, the pressure of the high-pressure gas source bottle is 1.5 times the expected coal seam gas pressure.

[0021] Compared with the prior art, the advantages and positive effects of the present invention are:

[0022] The present invention provides a simple, reliable and effective deep-hole gas pressure fixed-point measurement system and its measurement method. After the construction of the pressure measurement borehole is completed, a fixed pulley structure is formed at the bottom of the borehole by using a positioning and supporting component. The grouting hole-sealing mechanism and the pressure measurement pipe are lowered to the predetermined plugging and pressure measurement position by wire rope traction. Then, the borehole is sealed by using the grouting hole-sealing mechanism, and the gas is guided to the outside of the borehole through the pressure measurement pipe. The gas pressure data is directly read by using a pressure measurement instrument, and finally the gas pressure measurement result is obtained. Through the design of the positioning and supporting component, the present invention can quickly tow the soft pressure measurement pipe and the grouting hole-sealing mechanism to the deep part of the borehole, solving the technical defect in the prior art that it is difficult to push the soft pressure measurement pipe to the deep part of the borehole, resulting in the inability to measure the gas pressure at the deep part of the borehole. Compared with the hole-sealing operation at the orifice of the pressure measurement borehole in the prior art, the present invention can plug at a position hundreds of meters deep in the borehole and form a relatively airtight pressure measurement gas chamber. On the one hand, the volume of the pressure measurement gas chamber can be reduced, the gas pressure balance time and pressure loss can be reduced, and on the other hand, the possible air leakage points in the long borehole can be avoided to the greatest extent, effectively improving the accuracy of the gas pressure measurement result and making a certain contribution to coal mining operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 It is a combined state structural schematic diagram of the positioning and supporting component;

[0025] Figure 2 It is a split state structural schematic diagram of the positioning and supporting component;

[0026] Figure 3 It is a structural schematic diagram of the constant pressure supply mechanism;

[0027] Figure 4 It is a hole-sealing connection schematic diagram for single-point fixed-point measurement of deep-hole gas pressure;

[0028] Figure 5 It is a hole-sealing connection schematic diagram for multi-point fixed-point simultaneous measurement of deep-hole gas pressure;

[0029] Figure 6 It is a framework flowchart of the measurement method in the present invention. EMBODIMENTS

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts, any modifications, equivalent replacements, improvements, etc., shall be included in the scope of protection of the present invention.

[0031] This embodiment discloses a deep hole gas pressure fixed-point measurement system, comprising a hole sealing pressure measurement component and a positioning support component, wherein the positioning support component is connected to the hole sealing pressure measurement component;

[0032] like Figure 1 、 Figure 2 As shown, the positioning support assembly 28 includes a diameter reducing member 5, a supporting pipe 1, a flexible telescopic strip 3, a movable ring 9, and a steel wire rope 6;

[0033] The reducer 5 has a rear end connected to the drill pipe by a thread, a front end connected to the support pipe 1, and a steel wire rope 6 fixed to the front end via a second connecting piece;

[0034] The support pipe 1 is a hollow cylinder with a closed cone at the front and a circular ring at the rear end, which can be mounted on the front end of the reducer 5. The front section of the support pipe 1 is provided with an air inlet 2, and the rear section is provided with a fixing groove 7 for key connection with the reducer 5. An internal fixing pin 8 (i.e., a first connecting member) is provided on the inner side of the middle portion of the support pipe 1, and a threading groove 4 is provided on the side of the internal fixing pin 8.

[0035] The front end of the flexible telescopic strip 3 is fixed to the upper part of the supporting pipe 1, and the rear end is fixed to the movable ring 9. There are several flexible telescopic strips 3, which are evenly arranged on the circumference of the supporting pipe 1.

[0036] The movable ring 9 is a hollow ring, which is embedded in the outer side of the support pipe 1. The movable ring 9 can slide along the outer side of the support pipe 1, and its sliding stroke is L3;

[0037] One end of the steel wire rope 6 is fixed to the front end of the reducer 5, and the other end of the steel wire rope passes through the inner fixing pin 8 inside the support pipe 1 and passes through the threading groove 4 to pass through the support pipe 1. The length of the steel wire rope 6 is L 绳索 Not less than 2 times the drilling depth L0, that is, L 绳索 ≥2L0.

[0038] The flexible telescopic strip 3 is in contact with the borehole wall and always remains in an extended state during the process of the drill rod pushing the positioning support assembly 28; the movable ring 9 is relatively fixed to the support pipe 1, and the movable ring 9 is in the initial position of its sliding stroke;

[0039] like Figure 2As shown in the figure, during the first slow drill withdrawal process of the positioning and supporting component 28, under the traction of the wire rope 6, its supporting pipe 1 displaces downward, the flexible telescopic strip 3 rubs against the drilling hole wall and gradually contracts, and the movable ring 9 moves upward relative to the supporting pipe 1, and finally stops near the fixed position of the flexible telescopic strip 3 and the supporting pipe 1. At this time, the flexible telescopic strip 3 is in full contact with the drilling hole wall and forms the maximum resistance to prevent the supporting pipe 1 from moving downward continuously, forming the setting and fixing of the supporting pipe 1. After the supporting pipe 1 is set and fixed, the gas in the pressure measuring air chamber (i.e., the inner part of the inner end of the drilling hole) passes through the air inlet hole 2 at the front section of the supporting pipe, the hollow area in the middle of the supporting pipe 1 and the part outside the setting position, realizing the normal flow of the gas.

[0040] The hole sealing and pressure measuring component includes a grouting pipe 23, a hole sealing bag, a liquid inlet pipe 22, a liquid return pipe, a pressure measuring pipe 24, a grouting pipe stop valve 25, a pressure measuring instrument 26, a high-pressure gas source bottle 10, a pressure reducing valve 11, a mucus tank 12, a mucus pressure gauge 13, and a connecting pipeline 14;

[0041] The grouting pipe 23, the liquid inlet pipe 22, the liquid return pipe, and the pressure measuring pipe 24 are all one-piece through pipes. Each pipeline is prepared in advance according to the hole sealing depth L1 of the pressure measuring drilling hole and fixed to each other, and the ends of each pipeline are aligned. Among them:

[0042] The length of the grouting pipe 23 is L 注浆 = L1;

[0043] The length of the liquid inlet pipe 22 is L 粘液 = (L1 - 2L 囊袋 - 5.5);

[0044] The length of the pressure measuring pipe 24 is L 测压 = (L1 + 1);

[0045] L 囊袋 is the length of a single hole sealing bag and is not less than 0.5 m, that is, L 囊袋 ≥ 0.5 m.

[0046] There are 4 hole sealing bags, namely the first hole sealing bag 15, the second hole sealing bag 16, the third hole sealing bag 17, and the fourth hole sealing bag 18. Among them, the first hole sealing bag 15 and the second hole sealing bag 16 are the first group of bag hole sealing units, and their spacing is 5 m; the third hole sealing bag 17 and the fourth hole sealing bag 18 are the second group of bag hole sealing units, and their spacing is 5 m; the spacing between the second hole sealing bag 16 and the third hole sealing bag 17 is 1 m. The first to fourth hole sealing bags 15 - 18 are all fixed on the grouting pipe 23.

[0047] A plug is provided at the front end of the grouting pipe 23, and it passes through the first to fourth hole-sealing bags 15 - 18, and check valves are provided in the first to fourth hole-sealing bags 15 - 18; blasting valves are provided between the first hole-sealing bag 15 and the second hole-sealing bag 16, and between the third hole-sealing bag 17 and the fourth hole-sealing bag 18.

[0048] The grouting pipe stop valve 25 is connected to the grouting pipe 23, and the pressure measuring instrument 26 is connected to the pressure measuring pipe 24;

[0049] The high-pressure gas source bottle 10 enters the mucus tank 12 through the pressure reducing valve 11 and the connecting pipeline 14, and presses the mucus in the mucus tank 12 into the liquid inlet pipe 22 (as Figure 3 shown);

[0050] The return liquid pipe is used for the air to flow out when pumping mucus, and a control valve is provided at its end;

[0051] The pressure setting of the pressure reducing valve 11 is P1;

[0052] The mucus pressure gauge 13 is provided at the front end of the liquid inlet pipe 22 for measuring the mucus pressure.

[0053] As Figure 4 shown, the grouting pipe, the hole-sealing bag, the liquid inlet pipe, the return liquid pipe, and the pressure measuring pipe constitute a hole-sealing and pressure measuring pipeline; after the hole-sealing and pressure measuring pipeline is lowered to the predetermined position by the positioning and supporting assembly, the grouting pump is used to pump cement slurry into the grouting pipe 23. The cement slurry reaches the check valve of the first hole-sealing bag 15 through the grouting pipe 23 and is injected into the first hole-sealing bag 15, and then is successively injected into the second to fourth hole-sealing bags 16 - 18. After the first to fourth hole-sealing bags 15 - 18 are fully inflated, the cement slurry in the grouting pipe 23 is pressurized and opens the blasting valves between the first hole-sealing bag 15 and the second hole-sealing bag 16, and between the third hole-sealing bag 17 and the fourth hole-sealing bag 18, and is respectively injected to form the first grouting section 19 and the second grouting section 20, completing the pumping of the cement slurry.

[0054] After the cement slurry solidifies for 24 hours, the constant pressure supply mechanism 27 (the constant pressure supply mechanism is a combination of the high-pressure gas source bottle and the mucus tank) is used to pump mucus into the liquid inlet pipe 22. The mucus reaches the space between the second hole-sealing bag 16 and the third hole-sealing bag 17 through the liquid inlet pipe 22 to form a mucus grouting section 21, completing the pumping of the mucus. The mucus pumping pressure is set to P1, and P1 is 1.5 times the expected coal seam gas pressure P0, that is, P1 = 1.5P0.

[0055] As Figure 4 、 Figure 6 shown, this embodiment discloses a method for measuring the fixed-point deep-hole gas pressure, including the following steps:

[0056] S1. Complete the construction of the directional pressure measurement borehole in the coal seam 29 according to the design, accurately record the borehole depth L0 and the lithological characteristics of the surrounding rock during the borehole construction process, and determine the borehole sealing depth L1 in combination with the borehole depth L0 and the lithological characteristics of the surrounding rock;

[0057] Among them, the borehole sealing depth L1 of the pressure measurement borehole should be such that the borehole sealing position is located in the deep part of the borehole and within the rock borehole section with relatively dense lithology near the coal-rock interface to minimize the volume of the pressure measurement air chamber as much as possible.

[0058] S2. Install the reducer on the front end of the drill pipe, slowly push the support pipe to the inner end of the borehole sealing position by using the drill pipe, and at the same time slowly extend the steel wire rope so that it extends synchronously with the support pipe in the borehole, and record the pushing depth L2 of the support pipe;

[0059] Among them, the pushing depth L2 of the support pipe should be greater than the borehole sealing depth L1 of the pressure measurement borehole by no less than 2 m, that is, L2≥L1 + 2.

[0060] S3. Slowly withdraw the drill pipe for the first time, keep the part of the steel wire rope outside the borehole fixed, the support pipe and the reducer move out of the borehole along with the drill pipe, the movable ring slides and squeezes the flexible telescopic strip, and the outer side of the flexible telescopic strip abuts against the inner wall of the borehole, so that the support pipe and the borehole are supported and positioned;

[0061] S4. Slowly withdraw the drill pipe again until it is completely withdrawn from the borehole, and at the same time slowly extend the steel wire rope so that it retreats synchronously with the reducer in the borehole. After the reducer exits the borehole, the support pipe and the steel wire rope form a fixed pulley structure in the deep part of the borehole;

[0062] S5. Cut off the connection between one end of the steel wire rope and the reducer, and reconnect and fix it to one end of the pressure measurement pipe. Lower the sealing and pressure measurement pipeline formed by the pressure measurement pipe and the grouting pipe to the pressure measurement and plugging position in the borehole by pulling the other end of the steel wire rope. The lowering depth of the sealing and pressure measurement pipeline is the borehole sealing depth L1;

[0063] The steel wire rope 6 is fixed to the front end of the grouting pipe 23. At the same time, the part of the pressure measurement pipe 24 exceeding the front end of the grouting pipe 23 is also fixed to the steel wire rope 6; when lowering the pressure measurement pipe, drag the other end of the steel wire rope 6 to make it pull the sealing and pressure measurement pipeline to extend in the borehole until the lowering depth is L1.

[0064] S6. Outside the borehole, use the grouting pump to pump cement slurry into the grouting pipe, and the cement slurry seals the borehole; then pump mucus into the mucus grouting section to realize the mucus plugging operation of the borehole, and finally complete the complete sealing of the borehole;

[0065] S7. Install a pressure measurement instrument at the outer end of the pressure measurement pipe, use the pressure measurement instrument to carry out the gas pressure observation operation, and regularly record the coal seam gas pressure.

[0066] This embodiment also discloses a method for simultaneously measuring multi-point deep-hole gas pressure, which is applicable to the directional comb-shaped boreholes in the coal seam floor. As Figure 5 shown, this measurement method includes a positioning and supporting assembly 28, first to third hole-sealing and pressure-measuring pipelines (constituted by a grouting pipe, a hole-sealing bladder, a liquid inlet pipe, a liquid return pipe, and a pressure-measuring pipe combination) 36-38, and first to third hole-sealing and pressure-measuring systems (i.e., pressure-measuring instruments) 39-41.

[0067] After the construction of the directional comb-shaped boreholes in the coal seam floor is completed, accurately record the depths of each branch hole. Fix the first to third hole-sealing and pressure-measuring pipelines 36-38 together according to the designed hole-sealing depth, and align the ends of each pipeline. Fix the first hole-sealing and pressure-measuring pipeline 36 on the steel wire rope 6, tow the steel wire rope 6, and lower the first to third hole-sealing and pressure-measuring pipelines 36-38 to the predetermined depth. Then, pump cement slurry into the first hole-sealing pipeline 36, the second hole-sealing pipeline 37, and the third hole-sealing pipeline 38 in sequence. After the cement slurry solidifies for 24 hours, pump mucus into the first hole-sealing pipeline 36, the second hole-sealing pipeline 37, and the third hole-sealing pipeline 38 in sequence to simultaneously complete multi-point hole sealing. Then, connect the first hole-sealing pipeline 36 to the first hole-sealing and pressure-measuring system 39, the second hole-sealing pipeline 37 to the second hole-sealing and pressure-measuring system 40, and the third hole-sealing pipeline 38 to the third hole-sealing and pressure-measuring system 41 to conduct simultaneous multi-point gas pressure observation.

[0068] Different from the single-point fixed-point measurement method for deep-hole gas pressure, in the multi-point fixed-point simultaneous measurement method for deep-hole gas pressure, the first hole-sealing section 30 is the entire area of the borehole between the first pressure-measuring gas chamber 33 and the second pressure-measuring gas chamber 34, the second hole-sealing section 31 is the entire area of the borehole between the second pressure-measuring gas chamber 34 and the third pressure-measuring gas chamber 35, and only the third hole-sealing section 32 is consistent with the hole-sealing structure of the single-point fixed-point measurement for deep-hole gas pressure.

[0069] The present invention provides a simple, reliable and effective deep-hole gas pressure fixed-point measurement system and its measurement method. After the construction of the pressure measurement borehole is completed, a fixed pulley structure is formed at the bottom of the borehole by using the positioning and supporting assembly. The grouting hole sealing mechanism and the pressure measurement pipe are lowered to the predetermined plugging and pressure measurement position by wire rope traction. Then, the borehole is sealed by using the grouting hole sealing mechanism, and the gas is guided to the outside of the borehole through the pressure measurement pipe. The gas pressure data is directly read by using the pressure measurement instrument, and finally the gas pressure measurement result is obtained. Through the design of the positioning and supporting assembly, the present invention can quickly pull the soft pressure measurement pipe and the grouting hole sealing mechanism to the deep part of the borehole, solving the technical defect in the prior art that it is difficult to push the soft pressure measurement pipe to the deep part of the borehole, resulting in the inability to measure the gas pressure at the deep part of the borehole. Compared with the plugging operation at the orifice of the pressure measurement borehole in the prior art, the present invention can plug at a position hundreds of meters deep in the borehole and form a relatively airtight pressure measurement gas chamber. On the one hand, it can reduce the volume of the pressure measurement gas chamber, reduce the gas pressure balance time and pressure loss. On the other hand, it can avoid the possible air leakage points in the long borehole to the greatest extent, effectively improving the accuracy of the gas pressure measurement result and making a certain contribution to coal mine mining operations.

Claims

1. A deep-hole gas pressure fixed-point measurement system, including a hole-sealing pressure measurement component, characterized in that: The deep-hole gas pressure fixed-point measurement system further includes a positioning and supporting assembly, which is connected to the hole-sealing pressure measurement assembly; the hole-sealing pressure measurement assembly includes a grouting hole-sealing mechanism, a gas measurement mechanism, and a constant-pressure supply mechanism. The constant-pressure supply mechanism is arranged outside the drill hole, and the constant-pressure supply mechanism is connected to the grouting hole-sealing mechanism arranged in the drill hole; the positioning and supporting assembly is located inside the drill hole, and the gas measurement mechanism passes through the grouting hole-sealing mechanism from the outside of the drill hole and is connected to the positioning and supporting assembly; the positioning and supporting assembly includes a steel wire rope, a clamping mechanism, and a limiting mechanism. The clamping mechanism is clamped to the inner wall of the drill hole through the limiting mechanism, and one end of the steel wire rope bypasses the clamping mechanism and is connected to the gas measurement mechanism; The clamping mechanism includes a support pipe and a diameter-changing part. The support pipe is a circular pipe, one end of the support pipe is arranged in a sealed state, and a plurality of air inlet holes are arranged on the side wall of one side of the sealed end of the support pipe. The other end of the support pipe is open, and the open end of the support pipe is connected with the diameter-changing part. One end of the diameter-changing part is slidably sleeved inside the support pipe, and there is a key connection between one end of the diameter-changing part and the support pipe. The other end of the diameter-changing part is threadedly connected to the drill rod end. A first connecting part is arranged inside the middle of the support pipe, and a wire groove is arranged on the side wall of the support pipe. One end of the steel wire rope is connected to a second connecting part arranged at one end of the diameter-changing part, and the other end of the steel wire rope bypasses the first connecting part and passes out of the drill hole from the wire groove on the side wall of the support pipe; when the steel wire rope is connected to the gas measurement mechanism, the steel wire rope is disconnected from the second connecting part and is connected to the gas measurement mechanism.

2. The deep-hole gas pressure fixed-point measurement system according to claim 1, characterized in that: The limiting mechanism includes a flexible telescopic strip and a movable ring; the flexible telescopic strip and the movable ring are both sleeved outside the middle of the support pipe. One end of the flexible telescopic strip close to the sealed end of the support pipe is fixedly connected to the outer wall of the support pipe, and one end of the flexible telescopic strip close to the open end of the support pipe is fixedly connected to the movable ring. The movable ring is slidably connected to the support pipe and can slide along the axial direction of the support pipe.

3. The deep-hole gas pressure fixed-point measurement system according to claim 2, wherein: The grouting hole-sealing mechanism includes a grouting pipe and two groups of bag hole-sealing units. The two groups of bag hole-sealing units are arranged in sequence along the axis direction of the drill hole. Each group of bag hole-sealing units includes two bags, and the two bags are arranged in sequence along the axis direction of the drill hole. The grouting pipe passes through the four bags in the two groups of bag hole-sealing units in sequence. One end of the grouting pipe is arranged in a sealed state, and the other end of the grouting pipe is communicated with a grouting device; four first grouting ports are arranged on the outer side wall of the grouting pipe, and the four first grouting ports are respectively located inside the four bags, and check valves are arranged inside the first grouting ports; two second grouting ports are arranged on the outer side wall of the grouting pipe, and the two second grouting ports are respectively located between the two bags in the two groups of bag hole-sealing units, and blasting valves are arranged inside the second grouting ports.

4. The deep-hole gas pressure fixed-point measurement system according to claim 3, characterized in that: The constant-pressure supply mechanism includes a liquid inlet pipe, a liquid return pipe, a high-pressure gas source bottle, and a mucus tank. One ends of the liquid inlet pipe and the liquid return pipe are located between the two groups of bag hole-sealing units. The other ends of the liquid inlet pipe and the liquid return pipe pass through one group of bag hole-sealing units and extend out of the drill hole. A control valve is arranged at the end of the liquid return pipe extending out of the drill hole. The end of the liquid inlet pipe extending out of the drill hole extends to the bottom end of the mucus tank, and the top end of the mucus tank is connected to the high-pressure gas source bottle through a pipeline.

5. The deep-hole gas pressure fixed-point measurement system according to claim 4, characterized in that: The gas measurement mechanism includes a pressure measuring pipe and a pressure measuring instrument. One end of the pressure measuring pipe is connected to the pressure measuring instrument located outside the drill hole, and the other end of the pressure measuring pipe sequentially passes through four air bags and is connected to one end of a steel wire rope.

6. A measurement method of the deep-hole gas pressure fixed-point measurement system as described in claim 5, characterized in that: It includes the following steps: S1. Complete the construction of the directional pressure measuring drill hole according to the design, accurately record the drill hole depth L0 and the surrounding rock lithology characteristics during the drill hole construction process, and determine the sealing depth L1 of the drill hole in combination with the drill hole depth L0 and the surrounding rock lithology characteristics. S2. Install the reducing part in the positioning mechanism at the front end of the drill pipe, slowly push the positioning mechanism to the inner end of the sealing position of the drill hole by using the drill pipe, and at the same time slowly extend the steel wire rope so that it extends in the drill hole synchronously with the positioning mechanism, and record the pushing depth L2 of the positioning mechanism. S3. Slowly withdraw the drill pipe for the first time, keep the part of the steel wire rope outside the drill hole fixed, the support pipe and the reducing part in the positioning mechanism move outward with the drill pipe, the movable ring in the limiting mechanism slides and squeezes the flexible telescopic strip, and the outer side of the flexible telescopic strip abuts against the inner wall of the drill hole, so that the support pipe and the drill hole are supported and positioned. S4. Slowly withdraw the drill pipe again until it is completely withdrawn from the drill hole, and at the same time slowly extend the steel wire rope so that it retreats in the drill hole synchronously with the reducing part. After the reducing part exits the drill hole, the support pipe and the steel wire rope form a fixed pulley structure in the deep part of the drill hole. S5. Cut off the connection between one end of the steel wire rope and the reducing part, and reconnect and fix it to one end of the pressure measuring pipe in the gas measurement mechanism. Pull the other end of the steel wire rope to tow the pressure measuring pipe and the grouting and sealing mechanism down to the pressure measuring and plugging position in the drill hole, and the lowering depth of the pressure measuring pipe is the sealing depth L1 of the drill hole. S6. Outside the drill hole, use the grouting equipment to pump cement slurry into the grouting pipe in the grouting and sealing mechanism, and the grouting and sealing mechanism plugs the drill hole; then use the constant pressure supply mechanism to pump mucus to realize the mucus plugging operation of the drill hole, and finally complete the complete sealing of the drill hole. S7. Install a pressure measuring instrument at the outer end of the pressure measuring pipe, use the pressure measuring instrument to carry out the gas pressure observation operation, and regularly record the coal seam gas pressure.

7. The measurement method of the deep hole gas pressure fixed-point measurement system according to claim 6, characterized in that: The pushing depth L2 of the positioning mechanism is greater than the sealing depth L1 of the drill hole by not less than 2 m; the length of the steel wire rope is not less than twice the drill hole depth L0.

8. The measurement method of the deep-hole gas pressure fixed-point measurement system according to claim 7, characterized in that: The pressure of the high-pressure gas source bottle is 1.5 times the expected coal seam gas pressure.

Images