A device for withdrawing a drill bit used in a coal seam drilling test

Abstract

The present application relates to the technical field of coal mining, and particularly relates to a retracted drill bit device for coal seam drilling test. The present application provides a retracted drill bit device for coal seam drilling test, which comprises a retraction device and a split device. The retraction device comprises a retraction main body in a columnar shape, a drill rod joint and a split interface arranged at two ends of the retraction main body respectively, the drill rod joint is fixedly connected with a drill rod, the split interface is connected with a bearing of the split device, a crushing device is arranged on the outer side surface of the retraction main body, the crushing device is driven to rotate by rotating the retraction main body, so as to crush the rock which hinders the retraction of the retraction device; one end of the split device away from the retraction device is fixed with one end of a test device in a linear shape, the retraction device and the split device are moved from one end of the drilling hole to the other end, so as to lay the test device in the drilling hole. The present application provides a retracted drill bit device for coal seam drilling test, which can lay the test device in the drilling hole.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, and in particular to a retraction drill bit device for coal seam drilling testing. Background Technology

[0002] During coal mining, the methane content in the borehole is high. If the methane is not extracted in time, it will affect the safe mining of coal.

[0003] In related technologies, gas extraction mainly relies on extraction systems to remove gas from boreholes. The negative pressure in the borehole varies with its depth. If the negative pressure cannot be determined, the efficiency of gas extraction will decrease. Therefore, it is necessary to install testing devices along the borehole to collect negative pressure values ​​and investigate the patterns of negative pressure within the borehole. However, it is difficult to lay these testing devices within the borehole.

[0004] To address the aforementioned problems, there is an urgent need for a device that allows the testing equipment to be laid in the borehole. Summary of the Invention

[0005] This invention provides a retraction drill bit device for coal seam borehole testing, which can be laid in the borehole.

[0006] In a first aspect, embodiments of the present invention provide a retraction drill bit device for coal seam drilling testing, including a retraction device and a split-action device;

[0007] The retraction device includes a columnar retraction body and drill pipe joints and a transfer interface respectively disposed at both ends of the retraction body. The drill pipe joints are fixedly connected to the drill pipes, and the transfer interface is connected to the bearing of the transfer device. A crushing device is disposed on the outer side of the retraction body. By rotating the retraction body, the crushing device is driven to rotate, so as to crush the rocks that are obstructing the retraction of the retraction device.

[0008] The end of the diverting device away from the retraction device is fixed to one end of the linear test device. The test device is laid in the borehole by moving the retraction device and the diverting device from one end of the borehole to the other end.

[0009] In one possible design, the crushing device includes blades that are plate-shaped and are disposed on the retraction body.

[0010] In one possible design, the crushing device further includes cutting teeth, which are columnar and one end of which is fixed to the blade.

[0011] In one possible design, when the retraction device retracts, the blade rotates with the retraction body, and the cutting teeth are located on the side of the blade facing the direction of rotation.

[0012] In one possible design, the retraction body is provided with a plurality of blades, two blades and the retraction body form a chip removal groove, and each chip removal groove is provided with a nozzle on the retraction body, the nozzle being used to spray high-pressure fluid to flush the chip removal groove.

[0013] In one possible design, the nozzle is positioned near the retraction direction, which is the direction in which the retraction device moves when the test device is laid.

[0014] In one possible design, the nozzle is located near the cutting blade wing facing the chip removal groove.

[0015] In one possible design, the drill pipe, the drill pipe joint, and the retraction body all include hollow structures inside, the hollow structures being used to transmit high-pressure fluid, and the nozzle communicating with the hollow structure of the retraction body.

[0016] In one possible design, the retraction device is connected to the bearing of the transfer device via a connecting device, the connecting device being fixedly connected to the retraction device, and the connecting device being connected to the bearing of the transfer device.

[0017] Secondly, embodiments of the present invention provide a method for laying out a testing device, based on any of the systems described above, the method comprising:

[0018] The retraction device is connected to the drill pipe; wherein the test device is fixed on the transfer device;

[0019] The transfer device is rotatably connected to the retraction device;

[0020] The drill pipe is used to drive the retraction device to rotate;

[0021] The drill rod is used to move the retraction device and the diversion device from one end of the borehole to the other end to lay the test device in the borehole.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] After drilling through the borehole, the drill bit is removed, and a retraction device is installed on the drill rod. A transfer device is installed on the retraction device, and one end of a linear test device is fixed on the transfer device. When laying the test device, rotating the drill rod drives the crushing device on the retraction device to rotate and crush the rocks in the borehole that are hindering the retraction and laying. At the same time, the drill rod drives the retraction device and the transfer device to retract from the borehole, and the linear test device fixed on the transfer device follows the transfer device to complete the laying in the borehole.

[0024] It should be noted that since the retraction device and the transfer device are connected by a bearing, the transfer device will not rotate synchronously during the retraction process. Therefore, the transfer device can remain stationary during the laying process to smoothly lay the test device. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a retraction drill bit device for coal seam drilling testing provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of a drilling test system provided in one embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of a drilling test system provided in another embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of another drilling test system provided in one embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of another drilling test system provided in one embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of another drilling test system provided in another embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of another drilling test system provided in another embodiment of the present invention.

[0033] In the picture:

[0034] 1-Retraction device;

[0035] 11-The main body of the pullback;

[0036] 12-Drill pipe joint;

[0037] 13-Transfer interface;

[0038] 14- Crushing device;

[0039] 141-Blade Wing;

[0040] 142 - Cutting teeth;

[0041] 143 - Nozzle;

[0042] 15-Chip removal groove;

[0043] 2-Transfer transfer device;

[0044] 3-Testing apparatus;

[0045] 4-Bearings;

[0046] 5-Connecting device. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0048] like Figure 1 As shown, this embodiment of the invention provides a retraction drill bit device for coal seam drilling testing, including a retraction device 1 and a split-action device 2;

[0049] The retraction device 1 includes a columnar retraction body 11 and drill pipe joints 12 and a transfer interface 13 respectively disposed at both ends of the retraction body 11. The drill pipe joints 12 are fixedly connected to the drill pipe, and the transfer interface 13 is connected to the bearing 4 of the transfer device 2. A crushing device 14 is provided on the outer side of the retraction body 11. By rotating the retraction body 11, the crushing device 14 is driven to rotate, so as to crush the rocks that hinder the retraction of the retraction device 1.

[0050] The end of the transfer device 2 away from the retraction device 1 is fixed to one end of the linear test device 3. The test device 3 is laid in the borehole by moving the retraction device 1 and the transfer device 2 from one end of the borehole to the other end.

[0051] After drilling through the borehole, the drill bit is removed, and a retraction device 1 is installed on the drill rod. A transfer device 2 is installed on the retraction device 1, and one end of a linear test device 3 is fixed on the transfer device 2. When laying the test device 3, the drill rod is rotated to drive the crushing device 14 on the retraction device 1 to rotate and crush the rock in the borehole that is hindering the retraction and laying. At the same time, the drill rod drives the retraction device 1 and the transfer device 2 to retract from the borehole. The linear test device 3 fixed on the transfer device 2 follows the transfer device 2 to complete the laying in the borehole.

[0052] It should be noted that since the retraction device 1 and the transfer device 2 are rotatably connected by the bearing 4, the retraction device 1 will not drive the transfer device 2 to rotate synchronously during the rotation and retraction process. Therefore, during the laying process, the transfer device 2 can remain in a non-rotating state to smoothly lay the test device 3.

[0053] In some embodiments of the present invention, the crushing device 14 includes a blade 141, which is plate-shaped and disposed on the retraction body 11.

[0054] In this embodiment, the plate-shaped blade 141 is more robust, and the plate-shaped blade 141 is easier to insert into the rock in the borehole. As the blade 141 rotates along the retraction body 11, it is easier to break the protruding surrounding rock, preventing the protruding surrounding rock from obstructing the retraction and the laying of the test device 3.

[0055] It is understood that there can be one or more blade wings 141, preferably four blade wings 141. Specifically, four blade wings 141 are provided on the outer cylindrical surface of the retraction body 11. The four blade wings 141 can be arranged perpendicularly to the retraction body 11, that is, the planes containing the four blade wings 141 all pass through the axis of the retraction body 11. More preferably, the four blade wings 141 are evenly distributed on the retraction body 11.

[0056] In this embodiment, the blade 141 is fixedly connected to the retraction body 11 by welding, preferably low-temperature brazing.

[0057] In some embodiments of the present invention, the crushing device 14 further includes a cutting tooth 142, which is columnar and one end of the cutting tooth 142 is fixed to the blade 141.

[0058] In this embodiment, the cutting tooth 142 can further increase the efficiency and effectiveness of the crushing device 14 in crushing the surrounding rock of the borehole. There can be one or more cutting teeth 142, preferably multiple. The sizes of the cutting teeth 142 can be the same or different. The cutting teeth 142 can be cylindrical or prismatic.

[0059] In this embodiment, the cutting teeth 142 are fixedly connected to the blade 141 by welding, preferably low-temperature brazing. The material of the cutting teeth 142 is a material with high hardness, such as diamond, preferably a lower-cost synthetic polycrystalline diamond impregnated block.

[0060] In some embodiments of the present invention, when the retraction device 1 retracts, the blade 141 rotates with the retraction body 11, and the cutting teeth 142 are disposed on the side of the blade 141 facing the direction of rotation.

[0061] In this embodiment, during the rotation of the retraction device 1, the blade 141 rotates with the main body in one direction. Therefore, the surface of the blade 141 facing the rotation direction will directly contact the surrounding rock of the borehole. Thus, the cutting teeth 142 are set on this surface of the blade 141 to increase the efficiency of breaking the surrounding rock of the borehole.

[0062] In some embodiments of the present invention, a plurality of blades 141 are provided on the retraction body 11, and two blades 141 and the retraction body 11 form a chip removal groove 15. Each chip removal groove 15 is provided with a nozzle 143 on the retraction body 11. The nozzle 143 is used to spray high-pressure fluid to flush the chip removal groove 15.

[0063] In this embodiment, a chip removal groove 15 is formed between the two blades 141 and the retraction body 11. After the crushing device 14 crushes the surrounding rock of the borehole, the crushed rock chips will accumulate in the chip removal groove 15. In order to prevent the rock chips in the chip removal groove 15 from continuously accumulating and hindering the rotation and retraction, a nozzle 143 is provided on the body of the chip removal groove 15. The nozzle 143 is used to spray high-pressure fluid to flush the chip removal groove 15.

[0064] In some embodiments of the present invention, the nozzle 143 is positioned near the retraction direction, which is the direction in which the retraction device 1 moves when the test device 3 is laid.

[0065] In this embodiment, the retraction device 1 retracts towards one end of the borehole, and the nozzle 143 is set on the side of the chip discharge groove 15 close to the retraction direction. With this setting, the high-pressure fluid sprayed from the nozzle 143 will flush the rock chips in the chip discharge groove 15 in the opposite direction of the retraction direction, and the rock chips flushed out of the chip discharge groove 15 will not hinder the retraction.

[0066] In some embodiments of the invention, the nozzle 143 is close to the blade 141 of the cutting tooth 142 facing the chip removal groove 15.

[0067] In this embodiment, the chip removal groove 15 includes two blades 141. The cutting teeth 142 of one blade 141 face the chip removal groove 15, and the cutting teeth 142 of the other blade 141 face away from the chip removal groove 15. The rock chips in the chip removal groove 15 are mainly concentrated near the blade 141 with the cutting teeth 142 facing the chip removal groove 15. Therefore, the nozzle 143 is positioned close to the blade 141, which is more conducive to discharging the rock chips from the chip removal groove 15.

[0068] In some embodiments of the present invention, the drill pipe, drill pipe joint 12 and retraction body 11 all include a hollow structure inside, the hollow structure is used to transmit high pressure fluid, and the nozzle 143 is in communication with the hollow structure of the retraction body 11.

[0069] In this embodiment, high-pressure fluid flows from the hollow structure inside the drill pipe through the hollow structure of the drill pipe joint 12 and the retraction body 11, and is finally ejected by the nozzle 143.

[0070] In some embodiments of the present invention, the retraction device 1 is connected to the bearing 4 of the transfer device 2 via the connecting device 5, the connecting device 5 is fixedly connected to the retraction device 1, and the connecting device 5 is connected to the bearing 4 of the transfer device 2.

[0071] In this embodiment, the connecting member enables a better rotational connection between the retraction device 1 and the transfer device 2. Alternatively, the retraction device 1 and the transfer device 2 can be directly connected via the bearing 4.

[0072] This invention provides a method for laying out a test device 3, based on any of the above systems, the method comprising:

[0073] The retraction device 1 is connected to the drill pipe; wherein, the test device 3 is fixed on the transfer device 2;

[0074] Rotate the transfer device 2 onto the retraction device 1;

[0075] The drill pipe drives the retraction device 1 to rotate;

[0076] The drill rod is used to move the retraction device 1 and the diversion device 2 from one end of the borehole to the other end to lay the test device 3 in the borehole.

[0077] The method for laying the test device 3 provided in this embodiment is based on the same inventive concept as the system embodiment for laying the test device 3 described above. Therefore, it can achieve the same beneficial effects. For specific beneficial effects, please refer to the system embodiment described above.

[0078] After the test device 3 is installed, the negative pressure at different depths of the borehole can be calculated based on the test results of the test device 3.

[0079] Please refer to Figure 2 This invention provides a method for calculating negative pressure in boreholes, comprising:

[0080] The test system is laid in the borehole using a system for laying the test device 3; wherein the test device 3 includes multiple test tubes, each test tube including an air extraction end and a test end, and the multiple test ends are located at different depths of the borehole;

[0081] For each test tube, perform the following steps:

[0082] Connect the extraction system to the borehole;

[0083] Connect one end of the negative pressure gauge to the suction end and seal the other end of the negative pressure gauge.

[0084] Start the extraction system and record the first negative pressure value of the negative pressure gauge;

[0085] A negative pressure calculation model is established based on multiple first negative pressure values ​​and the depth of multiple test terminals;

[0086] The negative pressure value at any borehole depth is calculated using a negative pressure calculation model.

[0087] In this embodiment, multiple test tubes are set up, each including an extraction end and a test end. The test tubes have different lengths, and the test ends of the multiple test tubes are inserted into the borehole, placing them at different positions within the borehole. For each test tube, the following test operations are performed: the extraction system is connected to one end of the borehole; one end of a negative pressure gauge is connected to the extraction end, and the other end of the negative pressure gauge is sealed; the extraction system is turned on to extract gas from the borehole. Since the extraction end is connected to one end of the negative pressure gauge, the other end of the negative pressure gauge is sealed, and the test end is located in the borehole, the gas in the borehole is continuously extracted. Therefore, the first negative pressure value displayed by the negative pressure gauge is the negative pressure value of the test tube at that depth. After measuring the first negative pressure value of each test tube, different negative pressure values ​​(first negative pressure values) at different depths (depth of the test section) in the borehole are obtained, thus obtaining the mapping relationship between borehole depth and negative pressure value, i.e., the negative pressure calculation model. After obtaining the negative pressure calculation model, the negative pressure value at any borehole depth can be calculated.

[0088] In this embodiment, the flow meter can also be connected in series with the negative pressure gauge, and the flow meter can measure the flow rate of the test tube.

[0089] It is understandable that, such as Figure 2 As shown, closing the valve between the extraction system and the flow meter achieves the effect of sealing the extraction end in this embodiment.

[0090] It should be noted that the gas extraction end can be connected through a gas extraction single bundle tube. In addition to being connected to the extraction system, the gas extraction single bundle tube is also connected to the extraction pump. Then, a gas sampler is connected to the extraction pump to obtain the changes in negative pressure and concentration at each monitoring point (test end) of the extraction borehole over time during the extraction cycle, as well as the changes in negative pressure and concentration along the extraction borehole.

[0091] In this embodiment, the testing device includes multiple test tubes and an outer sheath, with the multiple test tubes enclosed within the outer sheath. The suction end of each test tube is located at the same end of the testing device, while the test ends are located at different positions within the testing device. To facilitate negative pressure testing at the test ends of the test tubes, air sampling nozzles are provided at the positions of the outer sheath corresponding to different test ends, allowing the test ends to communicate with the borehole.

[0092] like Figure 2 As shown, in some embodiments of the present invention, it further includes:

[0093] For each test tube, perform the following steps:

[0094] The extraction system is connected to the borehole and the extraction end respectively; a negative pressure gauge is installed between the extraction end and the extraction system.

[0095] Start the extraction system and record the second negative pressure value of the negative pressure gauge;

[0096] For each test tube, the first theoretical value is determined based on the second negative pressure value measured by the test tube and the tube diameter ratio of the test tube;

[0097] A negative pressure calculation model is established based on multiple initial negative pressure values ​​and the depth of multiple test terminals, including:

[0098] Multiple first theoretical values ​​are used to verify multiple first negative pressure values, resulting in multiple first verification negative pressure values;

[0099] A negative pressure calculation model is established based on multiple first theoretical values, multiple first verification negative pressure values, and the depth of multiple test terminals.

[0100] Since the first negative pressure value measured in the above embodiment is the actual negative pressure value measured at the test end, any problem with any device or component in the test system will affect the first negative pressure value, causing a large deviation between the measured first negative pressure value and the negative pressure value in the borehole. Therefore, this embodiment is designed to find the large deviation value in the first negative pressure value.

[0101] In this embodiment, for each test tube, the extraction system is connected to both the borehole and the extraction end, and the extraction system simultaneously extracts gas from both ends. Since the extraction system directly extracts gas from the extraction end, while indirectly extracting gas from the test end through the borehole, the negative pressure at the extraction end is higher, causing gas to flow from the test end to the extraction end. At this point, the test tube forms a negative pressure system, and the second negative pressure value displayed on the negative pressure gauge is the negative pressure value of this system. Further, the theoretical negative pressure value at the test end of the test tube, i.e., the first theoretical value, can be determined by the ratio of the second negative pressure value to the tube diameter. The first negative pressure value is verified using the first theoretical value of the same test tube. If the first theoretical value and the first negative pressure value deviate significantly, then the first negative pressure value is incorrect. After deleting the incorrect first negative pressure value, the remaining value is the correct first verification negative pressure value. In addition to verifying the first negative pressure value, the first theoretical value can also participate in the establishment of the negative pressure calculation model. The negative pressure calculation model established based on multiple first theoretical values, multiple first verified negative pressure values, and the depth of multiple test terminals is more accurate.

[0102] It should be noted that when the sampling system is connected to the same test tube, the first negative pressure value and the second negative pressure value of the test tube can be tested at the same time to improve the testing efficiency.

[0103] It is understandable that, such as Figure 2As shown, opening the valve between the extraction system and the flow meter allows the extraction system in this embodiment to simultaneously extract from the borehole and the extraction end.

[0104] In some embodiments of the present invention, multiple first negative pressure values ​​are verified using multiple first theoretical values ​​to obtain multiple first verification negative pressure values, including:

[0105] The first difference value is obtained by subtracting the first theoretical value and the first negative pressure value measured in the same test tube.

[0106] Mark the first difference that is higher than the first preset value;

[0107] Delete the first negative pressure value corresponding to the first difference marked with the label;

[0108] The first negative pressure value that was not deleted is determined as the first verification negative pressure value.

[0109] In this embodiment, the first theoretical value and the first negative pressure value of the same test tube are first subtracted to obtain the first difference value. Each first difference value is compared with the first preset value, and the first difference values ​​that are higher than the first preset value are marked. The first negative pressure value with the marked first difference value is the error value. After removing the error value, the remaining first negative pressure value is the first verification negative pressure value.

[0110] It should be noted that the first preset value can be an empirical value or determined by averaging multiple first differences. Specifically, 1.4 to 2 times the average can be used as the first preset value.

[0111] In some embodiments of the present invention, the first theoretical value is obtained by the following formula:

[0112] Δp=λ×l / d×(ρv 2 / 2)

[0113] L1=Δp-f2

[0114] Where Δp is the pressure drop, λ is the friction coefficient, l is the length of the test tube, d is the diameter of the test tube, ρ is the density of the fluid in the test tube, L1 is the first theoretical value, and f2 is the second negative pressure value.

[0115] In this embodiment, the pressure drop is obtained by considering the aspect ratio of the test tube, the fluid density, and the friction coefficient. The difference between the pressure drop and the second negative pressure value is the theoretical negative pressure value (first theoretical value) at the test end. The friction coefficient can be determined experimentally, and the fluid density can be determined by the gas concentration of the gas flowing through the test tube.

[0116] like Figure 3 As shown, in some embodiments of the present invention, it further includes:

[0117] For each test tube, perform the following steps:

[0118] Connect the extraction system to the borehole;

[0119] Connect one end of the negative pressure gauge to the suction end, and connect the other end of the negative pressure gauge to the outside of the borehole;

[0120] Turn on the extraction system and record the third negative pressure value of the negative pressure gauge;

[0121] For each test tube, the second theoretical value is determined based on the third negative pressure value measured by the test tube and the tube diameter ratio of the test tube;

[0122] A negative pressure calculation model is established based on multiple initial negative pressure values ​​and the depth of multiple test terminals, including:

[0123] Multiple second theoretical values ​​are used to verify multiple first negative pressure values ​​to obtain multiple second verification negative pressure values;

[0124] A negative pressure calculation model is established based on multiple second theoretical values, multiple second verification negative pressure values, and the depth of multiple test terminals.

[0125] In order to verify the first negative pressure value through multiple methods and angles, and to provide more data for establishing a negative pressure calculation model, this embodiment is designed to obtain the third negative pressure value and the second theoretical value.

[0126] In this embodiment, for each test tube, an extraction system is connected to the borehole, with the extraction end open to the external environment of the borehole (i.e., the extraction end is not sealed and not connected to the extraction system). The extraction system extracts gas from the borehole. Because the extraction system extracts gas from the test end through the borehole, a large negative pressure is created at the test end. Since the extraction end is open to the external environment of the borehole, gas flows from the extraction end to the test end. At this time, the test tube forms a negative pressure system, and the third negative pressure value displayed by the negative pressure gauge is the negative pressure value of this system. Further, the theoretical negative pressure value of the test end of the test tube can be determined by the ratio of the third negative pressure value to the tube diameter, i.e., the second theoretical value. The second theoretical value of the same test tube is used to verify the first negative pressure value. If the second theoretical value and the first negative pressure value deviate significantly, then the first negative pressure value is incorrect. After deleting the incorrect first negative pressure value, the remaining value is the correct second verification negative pressure value. In addition to verifying the first negative pressure value, the second theoretical value can also participate in the establishment of the negative pressure calculation model. The negative pressure calculation model established based on multiple second theoretical values, multiple first verification negative pressure values, and the depth of multiple test terminals is more accurate.

[0127] It should be noted that when the sampling system is connected to the same test tube, the first negative pressure value and the third negative pressure value of the test tube can be tested at the same time to improve the testing efficiency.

[0128] It should be noted that because the flow direction of the gas in the test tube changes, the connection of the negative pressure gauge needs to be changed.

[0129] In some embodiments of the present invention, multiple first negative pressure values ​​are verified using multiple second theoretical values ​​to obtain multiple second verification negative pressure values, including:

[0130] The second difference value is obtained by subtracting the second theoretical value and the first negative pressure value measured in the same test tube.

[0131] Mark the second difference that is higher than the second preset value;

[0132] Delete the first negative pressure value corresponding to the marked second difference;

[0133] The first negative pressure value that was not deleted is determined as the second verification negative pressure value.

[0134] In this embodiment, the second theoretical value and the first negative pressure value of the same test tube are first subtracted to obtain a second difference value. Each second difference value is compared with a second preset value, and the second difference values ​​that are higher than the second preset value are marked. The first negative pressure value with the marked second difference value is the error value. After removing the error value, the remaining second negative pressure value is the second verification negative pressure value.

[0135] It should be noted that the second preset value can be an empirical value or determined by averaging multiple second differences. Specifically, 1.4 to 2 times the average can be used as the second preset value. The first preset value can be the same as or different from the second preset value.

[0136] In some embodiments of the present invention, the second theoretical value is obtained by the following formula:

[0137] Δp=λ×l / d×(ρv 2 / 2)

[0138] L2=Δp-f3

[0139] Where Δp is the pressure drop, λ is the friction coefficient, l is the length of the test tube, d is the diameter of the test tube, ρ is the density of the fluid in the test tube, L2 is the second theoretical value, and f3 is the third negative pressure value.

[0140] In this embodiment, the pressure drop is obtained by considering the aspect ratio of the test tube, the fluid density, and the friction coefficient. The difference between the pressure drop and the third negative pressure value is the theoretical negative pressure value (second theoretical value) at the test end. The friction coefficient can be determined experimentally, and the fluid density can be determined by the gas concentration of the gas flowing through the test tube.

[0141] like Figure 2 , 4As shown in Figure 5, in some embodiments of the present invention, two extraction systems are included, which are respectively arranged on both sides of the borehole.

[0142] Connecting the extraction system to the borehole includes:

[0143] Two extraction systems were connected to the two ends of the borehole, respectively.

[0144] Turn on the extraction system and record the first negative pressure value of the negative pressure gauge, including:

[0145] Start the two sampling systems separately and record the first negative pressure value of the negative pressure gauges respectively;

[0146] Simultaneously activate two sampling systems and record the first negative pressure value of the negative pressure gauge.

[0147] To ensure the measured data more closely approximates real-world data, extraction systems are installed at both ends of the borehole. Specifically, when measuring the first negative pressure value, extraction is performed at both ends of the borehole, and then simultaneously at both ends. These three extractions yield three first negative pressure values. This setup improves the accuracy of the first negative pressure value, reduces errors, and increases the data available for establishing the negative pressure calculation model.

[0148] It should be noted that in order to ensure that the negative pressure inside the extraction borehole reaches a balanced state, the extraction interval should be at least 6 days.

[0149] In this embodiment, Figure 2 , 4 The extraction valve in section 5 is in the closed state.

[0150] like Figure 2 , 4 As shown in Figure 5, in some embodiments of the present invention, two extraction systems are included, which are respectively arranged on both sides of the borehole.

[0151] The extraction system is connected to both the borehole and the extraction end, including:

[0152] Connect a extraction system to the first end and the extraction end of the borehole, respectively;

[0153] Connect another extraction system to the second end of the borehole;

[0154] Turn on the extraction system and record the second negative pressure value of the negative pressure gauge, including:

[0155] Simultaneously activate two extraction systems and record the second negative pressure value of the negative pressure gauge;

[0156] Disconnect the first end from the sampling system, and simultaneously turn on both sampling systems and record the second negative pressure value of the negative pressure gauge;

[0157] Disconnect the second end from the sampling system, and simultaneously turn on both sampling systems and record the second negative pressure value of the negative pressure gauge.

[0158] To ensure the measured data more closely approximates real-world data, extraction systems are installed at both ends of the borehole. Specifically, when measuring the second negative pressure value, extraction is performed separately at both ends of the borehole, and then simultaneously at both ends. This three-stage extraction process yields three second negative pressure values. This setup improves the accuracy of the second negative pressure value, reduces errors, and increases the data available for establishing the negative pressure calculation model.

[0159] In this embodiment, regardless of which end of the borehole is being pumped from, a pumping system needs to be connected to the pumping end. When one pumping system is pumping air through the pumping end and another pumping system is pumping air at one end of the borehole, it is necessary to ensure that the power of the two pumping systems is the same.

[0160] It should be noted that in order to ensure that the negative pressure inside the extraction borehole reaches a balanced state, the extraction interval should be at least 6 days.

[0161] In this embodiment, Figure 2 , 4 The extraction valve in section 5 is in the open state.

[0162] like Figure 3 , 6 As shown in Figure 7, in some embodiments of the present invention, two extraction systems are included, which are respectively disposed on both sides of the borehole;

[0163] Connecting the extraction system to the borehole includes:

[0164] Connect the two extraction systems to the two ends of the borehole respectively;

[0165] Turn on the extraction system and record the third negative pressure value of the negative pressure gauge, including:

[0166] Turn on the two sampling systems separately and record the third negative pressure value of the negative pressure gauge respectively;

[0167] Simultaneously activate two extraction systems and record the third negative pressure value of the negative pressure gauge.

[0168] To ensure the measured data more closely approximates real-world data, extraction systems are installed at both ends of the borehole. Specifically, when measuring the third negative pressure value, extraction is performed at both ends of the borehole separately, and then simultaneously at both ends. This three-stage extraction process yields three third negative pressure values. This setup improves the accuracy of the third negative pressure value, reduces errors, and increases the data available for establishing the negative pressure calculation model.

[0169] It should be noted that in order to ensure that the negative pressure inside the extraction borehole reaches a balanced state, the extraction interval should be at least 6 days.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A retraction drill bit device for coal seam drilling testing, characterized in that, It includes a retraction device (1) and a transfer device (2); The retraction device (1) includes a columnar retraction body (11) and drill pipe joints (12) and a transfer interface (13) respectively disposed at both ends of the retraction body (11). The drill pipe joints (12) are fixedly connected to the drill pipe, and the transfer interface (13) is connected to the bearing (4) of the transfer device (2). A crushing device (14) is provided on the outer side of the retraction body (11). By rotating the retraction body (11), the crushing device (14) is driven to rotate, so as to crush the rocks that hinder the retraction of the retraction device (1). The end of the transfer device (2) away from the retraction device (1) is fixed to one end of the linear test device (3). The test device (3) is laid in the borehole by moving the retraction device (1) and the transfer device (2) from one end of the borehole to the other end. The crushing device (14) includes a blade (141) which is disposed on the retraction body (11). The retraction device (1) is connected to the bearing (4) of the transfer device (2) via a connecting device (5). The connecting device (5) is fixedly connected to the retraction device (1) and the connecting device (5) is connected to the bearing (4) of the transfer device (2).

2. The apparatus according to claim 1, characterized in that, The blade (141) is plate-shaped.

3. The apparatus according to claim 2, characterized in that, The crushing device (14) also includes cutting teeth (142), which are columnar and one end of the cutting teeth (142) is fixed on the blade (141).

4. The apparatus according to claim 3, characterized in that, When the retraction device (1) retracts, the blade (141) rotates with the retraction body (11), and the cutting teeth (142) are arranged on the side of the blade (141) facing the direction of rotation.

5. The apparatus according to claim 4, characterized in that, The retraction body (11) is provided with a plurality of blades (141), and two blades (141) and the retraction body (11) form a chip removal groove (15). Each chip removal groove (15) is provided with a nozzle (143) on the retraction body (11). The nozzle (143) is used to spray high-pressure fluid to flush the chip removal groove (15). The drill pipe, the drill pipe joint (12), and the retraction body (11) all include a hollow structure inside, which is used to transmit high-pressure fluid. The nozzle (143) is connected to the hollow structure of the retraction body (11).

6. The apparatus according to claim 5, characterized in that, The nozzle (143) is positioned near the retraction direction, which is the direction in which the retraction device (1) moves when the test device (3) is laid.

7. The apparatus according to claim 5, characterized in that, The nozzle (143) is close to the cutting tooth (142) and the blade (141) facing the chip removal groove (15).

8. A method for laying out a testing device, characterized in that, Based on the apparatus of any one of claims 1-7, the method comprises: The retraction device (1) is connected to the drill pipe; wherein the test device (3) is fixed on the directional device (2). The transfer device (2) is rotatably connected to the retraction device (1); The drill rod is used to drive the retraction device (1) to rotate; The drill rod is used to move the retraction device (1) and the shunting device (2) from one end of the borehole to the other end to lay the test device (3) in the borehole.

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