A device and method for detecting gas leakage position of gas extraction borehole by fixed-point detection of bundled tube

Abstract

The invention discloses a device and method for detecting the position of gas leakage in a gas extraction borehole with a bundled tube type fixed point, which solves the technical problem of determining the precise position of the borehole leakage by measuring the gas concentration. The detection device comprises a bundled tube, a casing, an extraction tube, a sealing cover, a gas collection pump and a gas concentration detector. The bundled tube is composed of a plurality of gas guide tubes, a plurality of sealing rings are arranged in the casing, the sealing ring divides the casing into a plurality of measuring sections, a plurality of air inlets are arranged on the casing between two sealing rings, each gas guide tube of the bundled tube extends to a different measuring section respectively, a sealing medium is filled between the extraction tube and the borehole wall, and the extraction tube and the gas collection pump are connected by a hose; the above detection device is used to detect the gas concentration in a plurality of measuring sections respectively, and the method for determining the precise position of the borehole leakage by comparing the monitoring results, the device and the method have the advantages of convenient installation, simple and reliable structure, high measurement efficiency, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mining measurement, and in particular to a device for fixed-point detection of gas leakage positions in extraction boreholes during coal mine gas extraction, and a method for measuring gas leakage positions in gas extraction boreholes. Background Art

[0002] 93% of my country's coal production is underground mining, and more than 70% of coal mines are high-gas mines. In coal mining, gas is the associated gas of coal seams. Gas is the main threat to coal mine safety production. At the same time, gas is also an important supplementary energy source. Gas extraction is the main way to control coal mine gas and develop coalbed methane in coal mining areas. In the process of gas extraction, ensuring the sealing of the borehole is the prerequisite for ensuring the efficiency and concentration of gas extraction from the borehole.

[0003] At present, the extraction boreholes are mainly sealed with polyurethane, expansive cement and other polymer materials, but there is a lack of fixed-point and real-time detection methods for the quality of borehole sealing, which leads to differences in the quality of borehole sealing, resulting in high extraction volume of coalbed methane, but low extraction efficiency and utilization rate, resulting in a large amount of coalbed methane that cannot be utilized due to low gas concentration, and the unusable gas is vented to cause environmental pollution. Gas extraction concentration is an important indicator for measuring the quality of borehole sealing. The leakage position of the extraction borehole needs to be determined at the hole mouth and pipe interface, the extraction pipeline connection, the sealing section medium, the coal wall or the deep backhole of the borehole. Most of the existing detection methods use the change of gas pressure to determine the sealing quality of the borehole. Among them, patents CN102680187A, CN105114057A, CN202165074U and CN204882003U propose detection devices for measuring the sealing quality of the borehole by air pressure, and patent CN105114057A proposes an intelligent evaluation model for the sealing quality of the borehole, but the location and position of the gas leakage cannot be accurately determined. Therefore, the existing detection devices and detection methods have shortcomings and need further improvement. Summary of the invention

[0004] In order to solve the technical problem of more accurately and simply determining the gas leakage position of the gas extraction borehole and performing fixed-point inspection, the present invention provides a device and method for beam-tube fixed-point detection of the gas extraction borehole leakage position. The specific technical scheme is as follows:

[0005] A device for detecting gas leakage positions in gas extraction boreholes with a bundled tube type, comprising a bundled tube, a casing, an extraction tube, a sealing cover, a gas collection pump and a gas concentration detector; the bundled tube is inside the casing, the casing passes through the extraction tube, and the gas collection pump connects the casing and the gas concentration detector; the sealing cover comprises an outer sealing cover and an inner sealing cover, the outer sealing cover and the inner sealing cover respectively seal the two ends of the extraction tube; a plurality of sealing rings are arranged inside the casing, the sealing rings divide the casing into a plurality of measuring sections, and a plurality of air inlets are arranged on the casing between two sealing rings; the bundled tube is composed of a plurality of air guide tubes, and each air guide tube of the bundled tube extends to a different measuring section.

[0006] Preferably, each air duct of the bundle tube is painted with a different color, and the sealing ring is provided with a through hole, and the diameter of the through hole is equal to the diameter of the air duct.

[0007] Further preferably, the air inlet end of the air guide tube is arranged at the air inlet of the sleeve, and the air outlet end of the air guide tube is provided with an air valve.

[0008] Preferably, the outer sealing cover is arranged at the outer end of the borehole of the extraction tube, and the inner sealing cover is arranged at the inner end of the borehole of the extraction tube, and the inner sealing cover is connected to the extraction tube by a thread; the inner sealing cover is provided with a casing through hole, a groove is provided at the position of the through hole, a sealing ring is provided in the groove, a sealing gasket is pressed on the sealing ring, and a fixing hoop presses the sealing gasket tightly against the inner sealing cover.

[0009] Preferably, the sealing ring is made of high-elastic silicone, and sealing putty is coated on the contact position between the sealing ring and the sleeve.

[0010] Preferably, a sealing medium is filled between the extraction pipe and the borehole wall, the casing is connected to the gas collection pump via a hose, and the gas collection pump is connected to the gas concentration detector via a hose.

[0011] It is further preferred that a right-angle elbow is provided at the outer end of the borehole of the extraction pipe, and a gas concentration detection hole is provided on the extraction pipe.

[0012] A method for detecting the position of gas leakage in a gas extraction borehole at a fixed point, according to the above-mentioned device for detecting the position of gas leakage in a gas extraction borehole at a fixed point by a bundled tube, comprises the following steps:

[0013] ①Measure the original gas concentration of coal seams;

[0014] ② Assemble the bundled tube fixed-point detection device for the gas drainage borehole leakage position and insert it into the gas drainage borehole;

[0015] ③ Start extracting gas through the extraction pipe, and use a gas concentration detector to detect the gas concentration at the gas concentration detection hole on the extraction pipe;

[0016] ④ Close the gas valves on all gas pipes, then open the gas valve on each gas pipe in turn, start the gas collection pump, and record the gas concentration of each measuring section respectively;

[0017] ⑤ Determine the leakage location of the extraction borehole based on the gas concentration.

[0018] Preferably, the device for assembling a bundle tube type fixed-point detection of gas extraction borehole leakage position in step ② specifically includes: installing the multiple gas guide tubes and sealing rings of the bundle tube into the casing in sequence according to the measuring points, installing the inner sealing cover and the outer sealing cover, and connecting the gas collection pump and the gas concentration detector.

[0019] Preferably, in step ⑤, the gas leakage position of the extraction borehole is determined according to the gas concentration, wherein the gas leakage position is within the measuring section where the gas concentration becomes lower.

[0020] The beneficial effects of the present invention include:

[0021] (1) The location of the gas leak is determined by detecting the gas concentration, which realizes the detection of extraction quality and drilling sealing quality. Multiple gas pipes are used and divided into multiple measurement sections to measure the gas concentration in sequence, so as to accurately determine the location of the gas leak.

[0022] (2) The two ends of the extraction pipe are sealed by a sealing cover, especially where the casing passes through the sealing cover plate, a sealing ring, a sealing gasket and a fixing hoop are used to seal the passing position to ensure the airtightness of the device.

[0023] (3) The casing is divided into multiple measuring sections by using multiple sealing rings, an air inlet is set on the casing of each measuring section, and each air guide tube extends to the air inlet of a different measuring section, thereby ensuring that different measuring sections are measured through different air guide tubes.

[0024] (4) The device is used to quickly determine the location of gas leakage in the borehole and to detect the deep part of the extraction borehole, thereby determining the extraction efficiency of the borehole.

[0025] (5) The device has the advantages of easy installation, simple and reliable structure, high measurement efficiency, etc. It can realize fixed-point detection. The gas concentration measurement equipment has a simple structure and low material requirements, which reduces the measurement cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the installation structure of a bundled tube fixed-point detection device for gas extraction borehole leakage positions;

[0027] Figure 2 It is a schematic diagram of the structure of the casing part;

[0028] Figure 3 1. It is a schematic diagram of the installation structure of the inner sealing cover;

[0029] In the figure: 1-bundle tube; 11-air guide tube; 2-casing; 21-air inlet; 22-sealing ring; 3-extraction tube; 31-gas concentration detection hole; 32-right angle elbow; 33-sealing medium; 4-sealing cover; 41-outer sealing cover; 42-inner sealing cover; 421-casing through hole; 422-sealing ring; 423-sealing pad; 424-fixing hoop; 5-gas collection pump; 51-hose; 6-gas concentration detector. DETAILED DESCRIPTION

[0030] Combination Figures 1 to 3 The specific implementation of the device and method for detecting the location of gas leakage in a gas extraction borehole at a fixed point by a bundled tube type provided by the present invention is as follows.

[0031] Example 1

[0032] The structure of a bundled tube fixed-point detection device for gas extraction borehole leakage specifically includes a bundled tube 1, a casing 2, an extraction tube 3, a sealing cover 4, a gas collection pump 5 and a gas concentration detector 6. The bundled tube 1 is arranged in the casing 2 and wrapped by the casing, the casing 2 passes through the extraction tube 3, the gas collection pump 5 connects the casing and the gas concentration detector 6, the sealing cover 4 includes an outer sealing cover 41 and an inner sealing cover 42, and the outer sealing cover 41 and the inner sealing cover 42 are respectively sealed at both ends of the extraction tube 3. The space between the extraction tube 3 and the borehole wall is filled with a sealing medium 33, and the sealing medium 33 uses polyurethane, expansion cement or other polymer materials. The casing 2 and the gas collection pump 5 are connected by a hose 51, and the gas collection pump 5 is connected to the gas concentration detector 6 by a hose 51. The extraction tube 3 is provided with a right-angle elbow 32 at the outer end of the borehole, and the extraction tube 3 is provided with a gas concentration detection hole 31.

[0033] Among them, multiple sealing rings 22 are arranged in the casing 2, and the sealing rings 22 are made of high elastic silicone. Sealing glue is applied at the contact position between the sealing rings 22 and the casing 2. The sealing rings 22 divide the casing 2 into multiple measuring sections, and the number of measuring sections is determined according to the depth of the borehole. The premise is to ensure that a measuring section is arranged near the outer opening of the borehole, a measuring section is arranged near the inner sealing cover 42, and 1 to 10 measuring sections are arranged outside the extraction pipe 3 according to the borehole depth to be detected. In the measuring section between any two sealing rings 22, the casing 2 is provided with multiple air inlets 21, and the air inlets 21 are evenly distributed on the tube circumference of the casing 2. The bundle tube 1 is composed of a plurality of air guide tubes 11. The number of air guide tubes 11 is determined according to the number of measuring sections. The number of measuring sections is equal to the number of air guide tubes 11. Each air guide tube 11 of the bundle tube 1 extends to different measuring sections, and the air inlet end of the bundle tube 1 is arranged near the air inlet position. The air inlet end of the air guide tube 11 is arranged at the air inlet 21 of the casing, and the air outlet end of the air guide tube 11 is provided with an air valve, which is in a closed state and is opened sequentially during the detection process. Each air guide tube 11 of the bundle tube 1 is painted with a different color, and a through hole is provided on the sealing ring 22, and the diameter of the through hole is equal to the diameter of the air guide tube. The outer sealing cover is arranged at the outer end of the borehole of the extraction tube 3, and the inner sealing cover 42 is arranged at the inner end of the borehole of the extraction tube 3. The inner sealing cover 42 is connected to the extraction tube 3 by threads, and a casing through hole is provided on the inner sealing cover 42, and a groove is provided at the position of the casing through hole, and a sealing ring 422 is provided in the groove, and a sealing gasket 423 is pressed on the sealing ring 422, and a fixing hoop 424 presses the sealing gasket 423 tightly against the inner sealing cover.

[0034] A method for detecting the position of gas leakage in a gas extraction borehole at a fixed point, according to the above-mentioned device for detecting the position of gas leakage in a gas extraction borehole at a fixed point by a bundled tube, comprises the following steps:

[0035] ①Measure the original gas concentration of coal seams;

[0036] ② Assemble a bundle-tube fixed-point detection device for the location of gas leakage in gas extraction boreholes, and insert it into the gas extraction borehole; wherein, assembling the bundle-tube fixed-point detection device for the location of gas leakage in gas extraction boreholes specifically includes: installing the multiple gas guide tubes and sealing rings of the bundle tube into the casing in sequence according to the measuring point sequence, installing the inner sealing cover and the outer sealing cover, and connecting the gas collection pump and the gas concentration detector.

[0037] ③ Start extracting gas through the extraction pipe, and use a gas concentration detector to detect the gas concentration at the gas concentration detection hole on the extraction pipe;

[0038] ④ Close the gas valves on all gas pipes, then open the gas valve on each gas pipe in turn, start the gas collection pump, and record the gas concentration of each measuring section respectively;

[0039] ⑤ Determine the leakage location of the extraction borehole based on the gas concentration.

[0040] The leakage position of the extraction borehole is determined according to the gas concentration, and it is judged that the determined leakage position is within the measuring section where the gas concentration becomes lower.

[0041] Example 2

[0042] The structure of a bundled tube fixed-point detection device for gas extraction borehole leakage specifically includes a bundled tube 1, a casing 2, an extraction pipe 3, a sealing cover 4, a gas collection pump 5 and a gas concentration detector 6. The bundled tube 1 is arranged in the casing 2 and wrapped by the casing, the casing 2 passes through the extraction pipe, the gas collection pump 5 connects the casing 2 and the gas concentration detector 6, and the sealing cover 4 includes an outer sealing cover 41 and an inner sealing cover 42, and the outer sealing cover 41 and the inner sealing cover 42 are respectively sealed at both ends of the extraction pipe 3. The casing 2 uses a hard PVC pipe, and when the length of a single PVC pipe is not enough, a metal threaded steel joint is used to connect the PVC pipe; the air guide pipe 11 uses a semi-hard PE material pipe, and the space between the extraction pipe 3 and the borehole wall is filled with a sealing medium 33, and the sealing medium 33 uses polyurethane, expansion cement or other polymer materials. The casing 2 is connected to the gas collection pump 5 through a hose 51, and the gas collection pump 5 is connected to the gas concentration detector 6 through a hose 51. The extraction pipe 3 is provided with a right-angle elbow 32 at the outer end of the borehole, and a gas concentration detection hole 31 is provided on the extraction pipe 3. The gas concentration detector 6 uses an intrinsically safe infrared gas concentration detector, and the gas collection pump 5 uses a negative pressure gas sample collection pump.

[0043] A plurality of sealing rings 22 are arranged in the casing 2, and the sealing rings 22 are made of high elastic silicone, and sealing putty is applied at the contact position between the sealing rings 22 and the casing 2. The sealing rings 22 divide the casing 2 into 7 measuring sections, one measuring section is arranged near the outer opening of the borehole, one measuring section is arranged near the inner sealing cover 42, and a measuring section is arranged outside the extraction pipe 3 as appropriate according to the borehole depth to be detected. In the measuring section between the two sealing rings 22, the casing 2 is provided with a plurality of air inlets 21, and the air inlets 21 are evenly distributed on the circumference of the casing 2. In this embodiment, 7 air inlets 21 are arranged on the casing 2, the first air inlet A is arranged at a position of one third of the length from the borehole to the extraction pipe, the second air inlet B is arranged at a position of two thirds of the length from the borehole to the extraction pipe, the third air inlet C is arranged at a position 0.2m away from the inner sealing cover inside the extraction pipe, the fourth air inlet D is arranged at a position 1m away from the inner sealing cover outside the extraction pipe, the fifth air inlet E is arranged at a position 2m away from the inner sealing cover outside the extraction pipe, the sixth air inlet F is arranged at a position 5m away from the inner sealing cover outside the extraction pipe, and the seventh air inlet G is arranged at a position 8m away from the inner sealing cover outside the extraction pipe. The bundle pipe 1 is composed of 7 air guide pipes, each air guide pipe 11 of the bundle pipe 1 extends to different measuring sections respectively, and the air inlet end of the bundle pipe 1 is arranged near the air inlet 21 to facilitate rapid air intake. The air inlet end of the air guide tube 11 is arranged at the air inlet 21 of the casing, and the air outlet end of the air guide tube 11 is provided with an air valve, which is in a closed state and is opened in sequence during the detection process. Each air guide tube 11 of the bundle tube 1 can be painted with different colors or marked with different numbers for distinction, and a through hole is provided on the sealing ring 22, and the diameter of the through hole is equal to the diameter of the air guide tube. The outer sealing cover 41 is arranged at the outer end of the borehole of the extraction tube, and the inner sealing cover 42 is arranged at the inner end of the borehole of the extraction tube 3. The inner sealing cover 42 is connected to the extraction tube 3 by threads, and a casing through hole is provided on the inner sealing cover 42, and a groove is provided at the position of the casing through hole, and a sealing ring 422 is provided in the groove, and a sealing gasket 423 is pressed on the sealing ring 422, and a fixing hoop 424 presses the sealing gasket 423 tightly against the inner sealing cover.

[0044] A method for detecting the position of gas leakage in a gas extraction borehole at a fixed point, according to the above-mentioned device for detecting the position of gas leakage in a gas extraction borehole at a fixed point by a bundled tube, comprises the following steps:

[0045] ① Determine the original gas concentration Q of the coal seam 原 ;

[0046] ② Assemble a bundle-tube fixed-point detection device for the location of gas leakage in gas extraction boreholes, and insert it into the gas extraction borehole; wherein, assembling the bundle-tube fixed-point detection device for the location of gas leakage in gas extraction boreholes specifically includes: installing the multiple gas guide tubes and sealing rings of the bundle tube into the casing in sequence according to the measuring point sequence, installing the inner sealing cover and the outer sealing cover, and connecting the gas collection pump and the gas concentration detector.

[0047] ③ Start extracting gas through the extraction pipe, and use a gas concentration detector to detect the gas concentration at the gas concentration detection hole on the extraction pipe to obtain the gas concentration Q O ;

[0048] ④ Close the air valves on all air pipes, then open the air valve on each air pipe in turn, start the gas collection pump, and record the gas concentration of each measuring section, starting from the borehole inward as Q A , Q B , Q C , Q D , Q E , Q F and Q G ;

[0049] ⑤ Determine the leakage location of the extraction borehole based on the gas concentration.

[0050] Determination order Judgment conditions Leakage location 1 <![CDATA[Q O <Q A ]]> Extraction pipe outlet connection 2 <![CDATA[Q A <Q B ]]> Extraction pipe and sealing section 3 <![CDATA[Q B <Q C =Q D ]]> Drilling Sealing Section 4 <![CDATA[Q C <Q D ≤Q E =Q F =Q 原 ]]> Coal wall drilling 5 <![CDATA[Q E =Q F <Q G =Q 原 ]]> Deep drilling

[0051] The gas leakage position of the extraction borehole is determined according to the gas concentration. Specifically, Q 原 , Q O , Q A , Q B , Q C , Q D , Q E , Q F and Q G The concentration relationship is used to judge the sealing quality of the extraction pipe outlet connection, the extraction pipe sealing section, the borehole sealing section, the borehole coal wall and the deep part of the borehole in turn. The judgment is based on the table below. When a certain section is confirmed to be leaking, after repairing that end, it is necessary to re-measure according to the above measurement sequence when measuring again.

[0052] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A device for detecting the position of gas leakage in a gas extraction borehole by means of a bundled tube, characterized in that: It includes a bundle tube, a casing, an extraction tube, a sealing cover, a gas collection pump and a gas concentration detector; the bundle tube is inside the casing, the casing passes through the extraction tube, and the gas collection pump connects the casing and the gas concentration detector; the sealing cover includes an outer sealing cover and an inner sealing cover, and the outer sealing cover and the inner sealing cover respectively seal the two ends of the extraction tube; The sleeve is provided with a plurality of sealing rings, the sealing rings divide the sleeve into a plurality of measuring sections, and a plurality of air inlets are provided on the sleeve between two sealing rings; the bundle pipe is composed of a plurality of air guide pipes, and each air guide pipe of the bundle pipe extends to a different measuring section respectively; Each air guide tube of the bundle tube is painted with a different color, and the sealing ring is provided with a through hole, the diameter of the through hole is equal to the diameter of the air guide tube; The air inlet end of the air guide tube is arranged at the air inlet of the sleeve, and the air outlet end of the air guide tube is provided with an air valve; The outer sealing cover is arranged at the outer end of the borehole of the extraction tube, and the inner sealing cover is arranged at the inner end of the borehole of the extraction tube, and the inner sealing cover is connected to the extraction tube by a thread; a casing through hole is arranged on the inner sealing cover, a groove is arranged at the position of the through hole, a sealing ring is arranged in the groove, a sealing gasket is pressed on the sealing ring, and a fixing hoop presses the sealing gasket tightly against the inner sealing cover; a sealing medium is filled between the extraction tube and the wall of the borehole, the casing is connected to the gas collection pump by a hose, and the gas collection pump is connected to the gas concentration detector by a hose.

2. The device for detecting the position of gas leakage in a gas extraction borehole at a fixed point according to claim 1, characterized in that: The sealing ring is made of high-elastic silicone, and sealing putty is coated on the contact position between the sealing ring and the sleeve.

3. The device for detecting the position of gas leakage in a gas extraction borehole at a fixed point according to claim 1, characterized in that: A right-angle elbow is arranged at the outer end of the borehole of the extraction pipe, and a gas concentration detection hole is arranged on the extraction pipe.

4. A method for detecting the position of gas leakage in a gas extraction borehole at a fixed point, according to the device for detecting the position of gas leakage in a gas extraction borehole at a fixed point according to any one of claims 1 to 3, characterized in that: The following steps are involved: ①Measure the original gas concentration of coal seams; ② Assemble the bundled tube fixed-point detection device for the gas extraction borehole leakage position and insert it into the gas extraction borehole; ③ Start extracting gas through the extraction pipe, and use a gas concentration detector to detect the gas concentration at the gas concentration detection hole on the extraction pipe; ④ Close the gas valves on all gas pipes, then open the gas valve on each gas pipe in turn, start the gas collection pump, and record the gas concentration of each measuring section respectively; ⑤ Determine the leakage location of the extraction borehole based on the gas concentration.

5. A method for detecting the location of gas leakage in a gas extraction borehole at a fixed point according to claim 4, characterized in that: The device for assembling a bundle tube type fixed-point detection of gas extraction borehole leakage position in step ② specifically includes: installing the multiple gas guide tubes and sealing rings of the bundle tube into the casing in sequence according to the measuring point sequence, installing the inner sealing cover and the outer sealing cover, and connecting the gas collection pump and the gas concentration detector.

6. A method for detecting the location of gas leakage in a gas extraction borehole at a fixed point according to claim 4, characterized in that: In step ⑤, the leakage position of the extraction borehole is determined according to the gas concentration, wherein the leakage position is within the measuring section where the gas concentration becomes lower.

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