Drilling device and drilling method for ultra-thick limestone flood area of coal seam floor

Abstract

The invention relates to the technical field of coal seam drilling, and discloses a drilling device and a drilling method for an extremely thick limestone flood area of a coal seam floor. Two adjacent groups of double-wall drill rods of the device are connected through an adapter substitute, and the end part of the last group of double-wall drill rods is fixedly connected with a double-wall driving rod through an adapter substitute; a screw motor is assembled in the double-wall driving rod, a transmission seat is coaxially arranged at the end part of the double-wall driving rod, a flow direction control assembly for controlling the flow direction of washing liquid is assembled in the transmission seat, and a guide assembly is mounted at the other end of the transmission seat, so that targeted drilling is conveniently performed according to different water inrush coefficients on a water-resisting layer; the design structure of the treatment hole distribution net is optimized, the supporting strength of the water-resisting layer is enhanced, the working state of the drill bit is adjusted according to the water pressure in the drill hole, the working environment of the drill bit is improved through the change of high-pressure gushing water in the drill hole, and the situation that high-pressure gushing water generates large resistance to the bottom of the drill bit, and efficient rock crushing cannot be achieved is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of coal seam drilling, and in particular to a drilling device and a drilling method for a coal seam floor thick limestone flood-affected area. Background Art

[0002] It is necessary to conduct preliminary research on the geological and hydrogeological characteristics of the regional coal seam floor. It was found that the Ordovician limestone aquifer in the coal seam floor is the main aquifer. Therefore, it is necessary to carry out full-area coverage management of the Ordovician limestone layer. Nearly horizontal directional long drilling holes in coal mines are an efficient means of water disaster prevention and control, and have obvious potential technical advantages in draining roof water, exploring old empty water, and controlling bottom plate pressurized water.

[0003] At present, the commonly used drilling equipment on the market is the oil drilling rig, which can effectively complete the limestone drilling operation. During drilling, there are two methods for the mining of thin impermeable layers in coal mines and the ground area management of thick limestone aquifers: one is to construct a main hole on the ground and manage aquifers of different depths through cutting and pulling technology; the other method is to implement multiple main holes on the ground to manage aquifers of different depths.

[0004] However, in actual use, the current drilling equipment is only used to drill into the aquifer to form a distribution network of treatment holes, and to increase the thickness of the bottom plate aquifer by grouting. However, grouting through the distribution network of treatment holes can only solve the risk of water inrush in the thin aquifer of the bottom plate, but there is no drilling response measure for the thin aquifer on the top of the coal seam, which will cause the risk of water inrush at the top. Therefore, the drilling equipment currently on the market cannot adjust the drilling strategy accordingly according to the changes in the water inrush coefficients of the top and bottom aquifers of the coal mining area, resulting in the drilling equipment being unable to complete the drilling of the distribution network of treatment holes at one time after exploring the treatment holes, resulting in low drilling efficiency.

[0005] Therefore, the present invention solves the above-mentioned problems through a drilling device and a drilling method for a coal seam floor thick limestone flooded area. Summary of the invention

[0006] The purpose of the present invention is to provide a drilling device and a drilling method for a flood-affected area of ​​a thick layer of limestone on a coal seam floor, so as to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a drilling device for coal seam bottom plate thick limestone flood-prone areas, comprising several groups of double-wall drill rods with the same structure, two adjacent groups of double-wall drill rods are connected by a conversion joint, and the end of the last group of double-wall drill rods is fixedly connected to a double-wall drive rod through a conversion joint, a screw motor is installed inside the double-wall drive rod, a transmission seat is arranged coaxially at the end of the double-wall drive rod, and the transmission seat extends to the inside of the double-wall drive rod and is fixedly connected to the screw motor, a flow control component for controlling the flow direction of the flushing fluid is installed inside the transmission seat, a guide component is installed at the other end of the transmission seat, and a drill bit is connected to the output end of the guide component.

[0008] The guide assembly includes an articulated ball head hingedly assembled at the center of the end of the transmission seat, a fixing column is integrally formed on the articulated ball head, and the fixing column is fixedly installed on the drill bit, four groups of hydraulic telescopic cylinders are arranged along the circumferential direction on the outer edge of the end face of the transmission seat, and the end of each group of hydraulic telescopic cylinders is installed between the transmission seat and the drill bit through a ball head, and a corrugated sheath is encapsulated on the outer edge between the transmission seat and the drill bit.

[0009] Preferably, a first central flow channel is opened inside the double-wall drill pipe along the axis, a first internal annular flow channel is opened on one side of the inner outer edge of the double-wall drill pipe, and first guide channels connected to the first internal annular flow channel are opened on both end surfaces of the double-wall drill pipe.

[0010] Preferably, the conversion joint includes a limit ring which is sleeved on the outer walls of the double-wall drill rod and the double-wall drive rod, a limit seat is fixed on the inner wall of the limit ring, a central flow guide channel is opened at the center of the limit seat, and a second flow guide channel is evenly opened on the outer edge of the limit seat along the circumferential direction.

[0011] Preferably, a second central flow channel, a boosting flow channel and a circulation channel are sequentially arranged inside the double-walled drive rod along the axis, a second internal annular flow channel is opened on one side of the inner outer edge of the double-walled drive rod, and a third guide channel connected to the second internal annular flow channel is opened on the end face of the double-walled drill pipe close to the conversion joint, and the circulation channel and the second internal annular flow channel are connected through a bypass flow channel.

[0012] Preferably, the transmission seat includes a transmission cylinder rotatably assembled inside the circulation channel, one end of the transmission cylinder extending into the circulation channel is fixedly connected to a screw motor, and the other end of the transmission cylinder extends a double-walled drive rod integrally formed with a drill barrel, the articulated ball head is assembled on the drill barrel, and four groups of hydraulic telescopic cylinders are evenly articulated and assembled on the end face of the drill barrel through the ball head.

[0013] Preferably, an inner discharge channel is opened on the drill tube at a position corresponding to the bypass flow channel, and an outer discharge channel is opened on the drill tube at a position corresponding to the gap between the double-walled driving rod and the transmission seat, and a pressure detection valve is fixedly installed in the outer discharge channel.

[0014] Preferably, the screw motor includes a driving cylinder rotatably assembled inside the boost flow channel, and outer driving blades are evenly arranged on the outer wall of the driving cylinder along the circumferential direction, inner driving blades are evenly arranged on the inner wall of the driving cylinder along the circumferential direction, and guide grooves are evenly opened on the outer wall of the driving cylinder.

[0015] Preferably, the flow direction control component includes a sealing head slidably assembled inside the transmission cylinder, a pressure plate is slidably assembled inside the drill barrel, the sealing head and the pressure plate are connected by a connecting rod, a pressure spring is arranged on the side of the pressure plate close to the sealing head, the other end of the pressure spring is fixed on the inner wall of the drill barrel, and a transverse through-flow guide hole is opened on the sealing head.

[0016] Preferably, an underflow hole is provided in the drill bit, and a transverse fluid channel is provided on the articulated ball head, which connects the drill barrel and the underflow hole.

[0017] The present invention discloses a method for drilling in a flood-affected area of ​​a thick layer of limestone on a coal seam floor. The method is implemented by using the above-mentioned device for drilling in a flood-affected area of ​​a thick layer of limestone on a coal seam floor. The specific steps of the drilling method are as follows: S1: First, obtain the thickness of the aquifer to be transformed, including the top aquifer and the bottom aquifer of the coal seam; S2: Then, an exploration and treatment hole extending to the aquifer is drilled on the ground, wherein the exploration and treatment hole includes a straight hole section of the treatment hole and an inclined section of the treatment hole; S3: Then, according to the thickness of the aquifer to be transformed, a branch section is drilled at the tail end of the deflection section of the treatment hole to achieve the initial treatment hole drilling of the aquifer. At the same time, an upward or downward strengthening branch section is independently drilled at a position where the water inrush coefficient of the aquiclude is large, thereby completing the design of the aquifer treatment hole distribution network, and then controlling the drill bit to achieve drilling work according to the preset treatment hole distribution network; S4: During normal drilling, the flushing fluid is introduced into the first central flow channel in the double-wall drill pipe through the dual-channel water feeder, and then flows into the second central flow channel through the diversion central flow channel. As the aperture of the boosting flow channel gradually decreases, the flushing fluid forms a boosting force inside the boosting flow channel to drive the screw motor to rotate, thereby driving the transmission seat and the drill bit to rotate synchronously. The flushing fluid after driving the screw motor to rotate is directly introduced into the transmission barrel, and then flows into the drill barrel through the diversion flow hole to realize the circulation of the flushing fluid, which is convenient for completing the rock drilling operation with the flushing fluid when the drill bit rotates. When drilling in the aquifer, the guide assembly is controlled to drive the drill bit to adjust its angle relative to the transmission seat, so as to achieve the role of guiding drive according to the distribution network of treatment holes, change the drilling direction of the drill bit, and increase the drilling range of the drill bit.

[0018] Technical effects and advantages of the present invention: 1. The present invention changes the traditional drill bit installation method, and sets the drill bit and the transmission seat as a split type, and uses an articulated ball head to realize the follow-up steering of the drill bit, and the four groups of hydraulic telescopic cylinders can use the different extension lengths to drive the drill bit together with the articulated ball head to adjust the angle relative to the transmission seat, so as to adjust the drilling direction of the drill bit during drilling work, greatly increase the drilling range of the drilling device in the aquifer, improve the drilling range of the aquifer treatment hole, and be more conducive to the design of the treatment hole distribution network, and facilitate targeted drilling for different water inrush coefficients on the aquifer, optimize the design structure of the treatment hole distribution network, enhance the supporting strength of the aquifer, and avoid the risk of water inrush.

[0019] 2. The high-pressure water gushing inside the borehole of the present invention can always generate an impact force on the pressure detection valve, so that the water pressure of the high-pressure water gushing in the borehole can be detected by the pressure detection valve, which is convenient for adjusting the working state of the drill bit according to the water pressure in the borehole. The pressure value of the flushing liquid inside the transmission seat can be directly detected by the stretching amount of the pressure-bearing spring. In this way, combined with the water pressure in the borehole detected by the pressure detection valve, the return path of the flushing liquid is changed, and the working environment of the drill bit can be improved by the change of the high-pressure water gushing in the borehole, so that the flushing liquid can always circulate under the "low back pressure" state. By reducing the circulating pressure consumption of the flushing liquid, the invalid load of the mud pump can also be reduced, thereby ensuring the bottom hole power of the drill bit and avoiding the high-pressure water gushing from generating a large resistance to the bottom of the drill bit and failing to achieve efficient rock crushing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall first-view structure of the present invention; Figure 2 It is a schematic diagram of the overall structure of the present invention from a second viewing angle; Figure 3 It is a schematic diagram of the first overall cross-sectional structure of the present invention; Figure 4It is a second cross-sectional structural schematic diagram of the present invention as a whole; Figure 5 This is a schematic diagram of the double-wall drill pipe structure of the present invention; Figure 6 This is a schematic diagram of the conversion joint structure of the present invention; Figure 7 This is a schematic diagram of the double-walled driving rod structure of the present invention; Figure 8 This is a schematic diagram of the assembly structure of the screw motor, the transmission base and the drill bit of the present invention; Fig. 9 It is a schematic cross-sectional view of the assembly structure of the screw motor, transmission base and drill bit of the present invention.

[0021] In the figure: 1. double-wall drill pipe; 11. first central flow channel; 12. first inner annular flow channel; 13. first flow guide channel; 2. conversion joint; 21. limit ring; 22. limit seat; 23. flow guide central flow channel; 24. second flow guide channel; 3. double-wall drive rod; 31. second central flow channel; 32. booster flow channel; 33. circulation channel; 34. second inner annular flow channel; 35. bypass flow channel; 36. third flow guide channel; 4. screw motor; 41 , drive cylinder; 42, outer drive blade; 43, inner drive blade; 44, guide groove; 5, transmission seat; 51, transmission cylinder; 52, drill tube; 53, outer discharge channel; 54, pressure detection valve; 55, inner discharge channel; 6, flow control assembly; 61, plugging head; 62, connecting rod; 63, pressure plate; 64, pressure spring; 65, diversion hole; 7, guide assembly; 71, articulated ball head; 72, hydraulic telescopic cylinder; 73, corrugated sleeve; 8, drill bit. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] Embodiment 1: This embodiment provides Figures 1 to 9The drilling device for thick limestone flood-affected areas on the bottom of a coal seam shown in the figure comprises a plurality of groups of double-wall drill rods 1 with the same structure. The number of double-wall drill rods 1 installed is increased according to the actual drilling requirements. At the same time, two adjacent groups of double-wall drill rods 1 are connected by a conversion joint 2, and the end of the last group of double-wall drill rods 1 is fixedly connected to a double-wall drive rod 3 through the conversion joint 2, which can increase the connection stability while ensuring the effectiveness of the transmission. The double-wall drive rod 3 is internally equipped with a screw motor 4. When the flushing fluid is introduced into the double-wall drill rod 1, the flushing fluid The flow can drive the screw motor 4 to rotate, and a transmission seat 5 is arranged coaxially at the end of the double-walled driving rod 3, and the transmission seat 5 extends to the inside of the double-walled driving rod 3 and is fixedly connected to the screw motor 4. When the screw motor 4 rotates, it can drive the transmission seat 5 to rotate synchronously. The transmission seat 5 is equipped with a flow direction control component 6 for controlling the flow direction of the flushing liquid. A guide component 7 is installed at the other end of the transmission seat 5. The output end of the guide component 7 is connected to a drill bit 8. The transmission seat 5 can drive the drill bit 8 to rotate synchronously through the guide component 7 to realize drilling.

[0024] See also Figure 3 and Fig. 9 The guide assembly 7 includes an articulated ball head 71 hingedly assembled at the center of the end of the transmission seat 5, a fixing column is integrally formed on the articulated ball head 71, and the fixing column is fixedly installed on the drill bit 8, four groups of hydraulic telescopic cylinders 72 are arranged along the circumferential direction on the outer edge of the end face of the transmission seat 5, and the end of each group of hydraulic telescopic cylinders 72 is installed between the transmission seat 5 and the drill bit 8 through a ball head, and a corrugated sheath 73 is encapsulated on the outer edge between the transmission seat 5 and the drill bit 8.

[0025] The traditional drill bit installation method is changed, and the drill bit 8 and the transmission seat 5 are set to be split, and the articulated ball head 71 can be used to realize the follow-up steering of the drill bit 8, and the four groups of hydraulic telescopic cylinders 72 can drive the drill bit 8 together with the articulated ball head 71 to adjust the angle relative to the transmission seat 5 by utilizing the different extension lengths thereof, so as to adjust the drilling direction of the drill bit 8 during drilling work, greatly increase the drilling range of the drilling device in the aquifer, improve the drilling range of the aquifer treatment hole, and be more conducive to the design of the treatment hole distribution network, facilitate targeted drilling for different water inrush coefficients on the aquifer, optimize the design structure of the treatment hole distribution network, enhance the supporting strength of the aquifer, and avoid the risk of water inrush.

[0026] It should be noted that the purpose of the corrugated sheath 73 is to protect the drill bit 8 and the transmission seat 5 and to achieve a sealing effect. At the same time, it can provide a retreat space for the drill bit 8 to adjust its angle relative to the transmission seat 5, thereby facilitating the angle adjustment of the drill bit 8.

[0027] See also Figure 5A first central flow channel 11 is opened inside the double-wall drill pipe 1 along the axis, a first internal annular flow channel 12 is opened on one side of the inner outer edge of the double-wall drill pipe 1, and first guide channels 13 connected to the first internal annular flow channel 12 are opened on both end surfaces of the double-wall drill pipe 1.

[0028] See also Figure 6 The conversion joint 2 includes a limit ring 21 sleeved on the outer wall of the double-wall drill pipe 1 and the double-wall drive rod 3, a limit seat 22 is fixed on the inner wall of the limit ring 21, a guide center flow channel 23 is opened at the center of the limit seat 22, and a second guide channel 24 is evenly opened on the outer edge of the limit seat 22 along the circumferential direction. The limit seat 22 is installed between two groups of double-wall drill pipes 1 or between the double-wall drill pipe 1 and the double-wall drive rod 3, and the limit ring 21 is sleeved and installed between the two groups of double-wall drill pipes 1 or on the double-wall drill pipe 1 and the double-wall drive rod 3, so as to enhance the stability when installing the two groups of double-wall drill pipes 1 or the double-wall drill pipe 1 and the double-wall drive rod 3.

[0029] See also Figure 7 A second central flow channel 31, a boost flow channel 32 and a circulation channel 33 are sequentially arranged inside the double-walled driving rod 3 along the axis, a second internal annular flow channel 34 is opened on one side of the inner outer edge of the double-walled driving rod 3, and a third guide channel 36 connected to the second internal annular flow channel 34 is opened on the end surface of the double-walled drill pipe 1 close to the conversion joint 2, and the circulation channel 33 and the second internal annular flow channel 34 are connected through a bypass flow channel 35.

[0030] See also Figure 8 and Fig. 9 The transmission seat 5 includes a transmission cylinder 51 rotatably assembled inside the circulation channel 33. One end of the transmission cylinder 51 extends into the circulation channel 33 and is fixedly connected to the screw motor 4. The other end of the transmission cylinder 51 extends a double-walled drive rod 3 and is integrally formed with a drill barrel 52. An articulated ball head 71 is assembled on the drill barrel 52, and four groups of hydraulic telescopic cylinders 72 are evenly articulated and assembled on the end surface of the drill barrel 52 through ball heads.

[0031] When the screw motor 4 rotates, it can synchronously drive the drill bit 8 to rotate to complete the drilling work.

[0032] See also Figure 8 and Fig. 9 An inner discharge channel 55 is provided on the drill tube 52 at a position corresponding to the bypass flow channel 35, and an outer discharge channel 53 is provided on the drill tube 52 at a position corresponding to the gap between the double-walled driving rod 3 and the transmission seat 5. A pressure detection valve 54 is fixedly installed in the outer discharge channel 53. Since the outer discharge channel 53 is always connected to the borehole, the high-pressure water gushing inside the borehole can always generate an impact force on the pressure detection valve 54. In this way, the water pressure of the high-pressure water gushing in the borehole can be detected by the pressure detection valve 54, which is recorded as M2, so that the working state of the drill bit 8 can be adjusted according to the water pressure in the borehole.

[0033] See also Figure 8 The screw motor 4 includes a driving cylinder 41 rotatably assembled inside the boosting channel 32, and outer driving blades 42 are evenly arranged on the outer wall of the driving cylinder 41 along the circumferential direction, and inner driving blades 43 are evenly arranged on the inner wall of the driving cylinder 41 along the circumferential direction. Guide grooves 44 are evenly opened on the outer wall of the driving cylinder 41. The flow of flushing fluid inside the double-walled driving rod 3 can generate flow pressure, and the fluid pressure is used to drive the outer driving blades 42 and the inner driving blades 43 to rotate, and then drive the screw motor 4 to rotate, forming a driving force for the drill bit 8, realizing the conversion of fluid pressure energy into rotational mechanical energy, and realizing directional drilling.

[0034] See also Fig. 9 The flow direction control component 6 includes a plugging head 61 slidably assembled inside the transmission cylinder 51, and a pressure plate 63 is slidably assembled inside the drill tube 52. The plugging head 61 and the pressure plate 63 are connected by a connecting rod 62. A pressure spring 64 is arranged on the side of the pressure plate 63 close to the plugging head 61, and the other end of the pressure spring 64 is fixed on the inner wall of the drill tube 52. A transverse through-flow guide hole 65 is opened on the plugging head 61.

[0035] The flushing liquid driven by the screw motor 4 will be directly introduced into the transmission tube 51, and then flow into the drill tube 52 through the guide hole 65, so that the circulation of the flushing liquid can be achieved.

[0036] A bottom flow hole is provided in the drill bit 8, and a transverse fluid channel is opened on the articulated ball head 71, which connects the drill barrel 52 and the bottom flow hole. This ensures that the flushing fluid flowing from the inside can be introduced into the bottom flow hole from the fluid channel and sprayed out, and cooperates with the rotation of the drill bit 8 to achieve directional drilling. Subsequently, the flushing fluid merges with the formation water and returns from the borehole.

[0037] During the normal drilling process, the drill bit 8 performs drilling work according to the preset treatment hole distribution network, that is, first obtains the thickness of the aquifer to be transformed, including the top aquifer and the bottom aquifer of the coal seam, and then drills an exploratory treatment hole extending to the aquifer on the ground. The exploratory treatment hole includes a straight hole section of the treatment hole and an inclined section of the treatment hole. Subsequently, according to the thickness of the aquifer to be transformed, a branch section is drilled at the tail end of the inclined section of the treatment hole to achieve preliminary treatment hole drilling of the aquifer. At the same time, an upward or downward reinforced branch section is independently drilled at a position where the water inrush coefficient of the aquiclude is large.

[0038] It is worth noting that when the branch section is close to the upper part of the aquifer, several downward-inclined secondary branch sections are opened at equal distances along the length direction of the branch section, and the tail end of the secondary branch section is close to the lower part of the aquifer, and an upward-inclined exploration branch section is opened in the middle position of the branch section, and the exploration branch section extends a certain distance from the upper part of the aquifer.

[0039] When the branch section is close to the lower part of the aquifer, a number of upwardly inclined secondary branch sections are equidistantly opened along the length direction of the branch section, and the tail ends of the secondary branch sections are located at the lower part of the aquifer.

[0040] It is specially noted that when drilling the straight hole section, inclined section, branch section, secondary branch section and exploration branch section of the treatment hole in the aquifer, the guide component 7 is controlled to move, driving the drill bit 8 to adjust the angle relative to the transmission seat 5, so as to achieve the role of guiding and driving according to the treatment hole distribution network, change the drilling direction of the drill bit 8, increase the drilling range of the drill bit 8, and adjust the drilling strategy accordingly according to the changes in the water inrush coefficient of the top aquiclude and the bottom aquiclude of the coal mining area, so as to achieve the corresponding distribution of the treatment hole distribution network.

[0041] When drilling the reinforced branch section inside the aquifer, the four groups of hydraulic telescopic cylinders 72 can use their different extension lengths to drive the drill bit 8 together with the articulated ball head 71 to adjust the angle relative to the transmission seat 5, greatly increasing the drilling range of the drilling device in the aquifer, improving the drilling range of the aquifer treatment holes, and being more conducive to the design of the treatment hole distribution network. It is convenient to carry out targeted drilling for different water inrush coefficients on the aquifer, optimize the design structure of the treatment hole distribution network, enhance the supporting strength of the aquifer, and avoid the risk of water inrush.

[0042] It should be noted that when the amount of water flowing into the borehole increases, the water pressure also gradually increases, so that the resistance of the flushing fluid sprayed from the drill bit 8 when flowing back gradually increases, causing the flushing fluid pressure inside the transmission seat 5 to increase, which directly leads to an increase in the output power consumption of the mud pump.

[0043] In actual use, after the drill bit 8 reaches the bottom plate high-pressure water-bearing formation, under the action of the pressure difference (the formation pore pressure is greater than the circulating flow pressure of the flushing fluid in the hole), a large amount of high-pressure formation water flows into the borehole, increasing the annular return water volume and the flow rate, resulting in an increase in the circulating flow resistance of the flushing fluid and an increase in the bottom hole pressure (back pressure), which directly affects the flushing fluid pressure energy conversion amount, and then affects the working performance of the bottom hole drill bit 8, especially when the formation water gushing pressure reaches 3MPa~4MPa, directional drilling is difficult, which is prominently manifested in the increase of borehole annular return water volume, increase of bottom hole back pressure, significant increase of mud pump fluid supply pressure value, decrease of bottom hole power drill output torque, significant reduction of mechanical drilling speed, and difficulty in directional drilling. Therefore, under the condition of high-pressure formation water gushing, top water directional drilling is difficult, the hole depth often does not meet the design requirements, the water prevention and control effect is poor, and the drilling project needs to be supplemented and increased, which is costly and has a long cycle.

[0044] It is particularly noted that when the pressure of the flushing fluid inside the transmission seat 5 increases, as the pressure plate 63 moves, the pressure spring 64 is stretched accordingly. Therefore, the pressure value of the flushing fluid inside the transmission seat 5 can be directly detected by the stretching amount of the pressure spring 64. In this way, combined with the water pressure in the borehole detected by the pressure detection valve, the return path of the flushing fluid can be changed. The working environment of the drill bit 8 can be improved by the change of the high-pressure water gushing in the borehole, so that the flushing fluid can always circulate under the "low back pressure" state. By reducing the circulating pressure consumption of the flushing fluid, the invalid load of the mud pump can also be reduced, thereby ensuring the bottom hole power of the drill bit 8 and avoiding the high-pressure water gushing to generate greater resistance to the bottom of the drill bit and fail to achieve efficient rock crushing.

[0045] Based on this, the flushing fluid is introduced into the first central flow channel 11 in the double-wall drill pipe 1 through the double-flow channel water feeder, and then flows into the second central flow channel 31 through the diversion central flow channel 23. Since the aperture of the boosting flow channel 32 gradually decreases, the flushing fluid will form a boosting potential inside the boosting flow channel 32 to drive the screw motor 4 to rotate, thereby driving the transmission seat 5 and the drill bit 8 to rotate synchronously. The flushing fluid after driving the screw motor 4 to rotate will be directly introduced into the transmission barrel 51, and then flow into the drill barrel 52 through the diversion flow hole 65, which can realize the circulation of the flushing fluid, and facilitate the use of the flushing fluid to complete the rock drilling operation when the drill bit 8 rotates. The fluid pressure introduced from the screw motor 4 to the transmission seat 5 can be calculated by the tensile deformation of the pressure-bearing spring 64, which is recorded as M1, specifically: When the internal pressure M1 of the transmission seat 5 is much greater than the water gushing pressure M2 in the borehole, it is characterized as drilling under low back pressure conditions. At this time, since the sealing head 61 blocks the inner discharge channel 55 and the pressure detection valve is opened, part of the flushing fluid flows into the borehole through the outer discharge channel 53. In this way, the flushing fluid will merge with the formation water gushing in the borehole and return from the borehole.

[0046] When the internal pressure M1 of the transmission seat 5 is less than and close to the water gushing pressure M2 in the borehole, it is characterized as drilling under medium back pressure conditions. At this time, the pressure detection valve is closed, and the flushing fluid will not flow out through the external discharge channel 53. The flushing fluid will all flow through the transmission seat 5 and the drill bit 8 and be introduced into the bottom of the hole, so as to overcome the problem of increased back pressure caused by the increase in the water gushing pressure in the borehole. The circulation flow resistance of the flushing fluid is reduced by increasing the flow pressure of the flushing fluid. Subsequently, the flushing fluid and the formation water gushing in the borehole merge and return from the borehole. At this time, the return flow rate of the flushing fluid increases, and the flow rate also increases.

[0047] When the internal pressure M1 of the transmission seat 5 is greater than the water pressure M2 in the borehole, it is characterized as drilling under high back pressure conditions. At this time, the flow resistance of the flushing fluid increases significantly, so that the flushing fluid pressure inside the transmission cylinder 51 gradually increases, thereby pushing the pressure plate 63 to move, driving the pressure spring 64 to stretch, and then with the movement of the pressure plate 63, the plugging head 61 can be pushed down in the transmission cylinder 51 through the connecting rod 62, so that the plugging head 61 and the inner row channel 55 are staggered, so that the inner row channel 55 is connected, and the flushing fluid inside the transmission seat 5 flows into the bypass channel 35 along the inner row channel 55, and then The flushing liquid flows along the second internal annular flow channel 34, the third guide channel 36, the second guide channel 24, and the first internal annular flow channel 12 to realize the upward return of the flushing liquid, and the pressure detection valve is closed, so that the flushing liquid will not flow into the borehole from the external discharge channel 53, so that the upward return of the flushing liquid will not be affected by the water pressure in the borehole. Therefore, when the drilling device is drilling in the borehole, the upward return path of the flushing liquid can be adjusted in real time according to the change of the water pressure in the borehole, so as to ensure that the flushing liquid inside the drilling device always flows in a low back pressure state, which can reduce the load of the mud pump and greatly improve the drilling efficiency of the drilling device.

[0048] Embodiment 2: This embodiment provides a method for drilling in a flooded area of ​​thick limestone on the bottom of a coal seam. The method is implemented by using the drilling device for drilling in a flooded area of ​​thick limestone on the bottom of a coal seam as described in Example 1. The specific steps of the drilling method are as follows: S1: First, obtain the thickness of the aquifer to be transformed, including the top aquifer and the bottom aquifer of the coal seam; S2: Then, an exploration and treatment hole extending to the aquifer is drilled on the ground, wherein the exploration and treatment hole includes a straight hole section of the treatment hole and an inclined section of the treatment hole; S3: Then, according to the thickness of the aquifer to be transformed, a branch section is drilled at the tail end of the deflection section of the treatment hole to achieve the initial treatment hole drilling of the aquifer, and at the same time, an upward or downward strengthening branch section is independently drilled at a position where the water inrush coefficient of the aquifer is large, thereby completing the design of the aquifer treatment hole distribution network, and then controlling the drill bit 8 to achieve drilling work according to the preset treatment hole distribution network; S4: During normal drilling, the flushing fluid is introduced into the first central channel 11 in the double-wall drill pipe 1 through the dual-channel water feeder, and then flows into the second central channel 31 through the diversion central channel 23. Since the aperture of the boosting channel 32 gradually decreases, the flushing fluid forms a boosting force inside the boosting channel 32 to drive the screw motor 4 to rotate, thereby driving the transmission seat 5 and the drill bit 8 to rotate synchronously. The flushing fluid after driving the screw motor 4 to rotate is directly introduced into the transmission barrel 51, and then flows into the drill barrel 52 through the diversion hole 65 to realize the circulation of the flushing fluid, so that when the drill bit 8 rotates, the flushing fluid is used to complete the rock drilling operation. When drilling in the aquifer, the guide assembly 7 is controlled to move to drive the drill bit 8 to adjust the angle relative to the transmission seat 5, so as to achieve the role of guiding and driving according to the distribution network of treatment holes, change the drilling direction of the drill bit 8, and increase the drilling range of the drill bit 8.

[0049] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A drilling device for thick limestone flood-prone areas on coal seam floors, comprising a plurality of sets of double-walled drill rods (1) of the same structure, characterized in that: Two adjacent groups of double-wall drill rods (1) are connected via a conversion joint (2), and the end of the last group of double-wall drill rods (1) is fixedly connected to a double-wall drive rod (3) via the conversion joint (2), a screw motor (4) is installed inside the double-wall drive rod (3), a transmission seat (5) is arranged coaxially at the end of the double-wall drive rod (3), and the transmission seat (5) extends into the double-wall drive rod (3) and is fixedly connected to the screw motor (4), a flow control component (6) for controlling the flow direction of the flushing liquid is installed inside the transmission seat (5), a guide component (7) is installed at the other end of the transmission seat (5), and a drill bit (8) is connected to the output end of the guide component (7); The guide assembly (7) comprises an articulated ball head (71) hingedly assembled at the center of the end of the transmission seat (5); a fixing column is integrally formed on the articulated ball head (71), and the fixing column is fixedly mounted on the drill bit (8); four groups of hydraulic telescopic cylinders (72) are arranged along the circumferential direction on the outer edge of the end surface of the transmission seat (5); the end of each group of hydraulic telescopic cylinders (72) is mounted between the transmission seat (5) and the drill bit (8) through a ball head; and a corrugated sheath (73) is encapsulated on the outer edge between the transmission seat (5) and the drill bit (8).

2. The drilling device for thick limestone flooded areas on the coal seam floor according to claim 1, characterized in that: A first central flow channel (11) is provided inside the double-wall drill pipe (1) along the axis, a first internal annular flow channel (12) is provided on one side of the inner outer edge of the double-wall drill pipe (1), and first flow guide channels (13) communicating with the first internal annular flow channel (12) are provided on both end surfaces of the double-wall drill pipe (1).

3. The drilling device for thick limestone flooded areas on the coal seam floor according to claim 2, characterized in that: The conversion joint (2) comprises a limit ring (21) sleeved on the outer walls of the double-wall drill rod (1) and the double-wall drive rod (3); a limit seat (22) is fixed on the inner wall of the limit ring (21); a central flow guide channel (23) is provided at the center of the limit seat (22); and a second flow guide channel (24) is evenly provided on the outer edge of the limit seat (22) along the circumferential direction.

4. The drilling device for thick limestone flooded areas on coal seam floors according to claim 1, characterized in that: The double-walled driving rod (3) is provided with a second central flow channel (31), a pressurizing flow channel (32) and a circulation channel (33) in sequence along the axis, a second internal annular flow channel (34) is provided on one side of the inner outer edge of the double-walled driving rod (3), and a third flow guide channel (36) connected to the second internal annular flow channel (34) is provided on an end surface of the double-walled drilling rod (1) close to the conversion joint (2), and the circulation channel (33) and the second internal annular flow channel (34) are connected via a bypass flow channel (35).

5. The drilling device for thick limestone flooded areas on the coal seam floor according to claim 4, characterized in that: The transmission seat (5) comprises a transmission cylinder (51) rotatably mounted inside the circulation channel (33); one end of the transmission cylinder (51) extending into the circulation channel (33) is fixedly connected to the screw motor (4); a double-walled drive rod (3) is extended from the other end of the transmission cylinder (51) and is integrally formed with a drill cylinder (52); the articulated ball head (71) is mounted on the drill cylinder (52); and four groups of hydraulic telescopic cylinders (72) are evenly articulated and mounted on the end surface of the drill cylinder (52) via the ball heads.

6. The drilling device for thick limestone flooded areas on the coal seam floor according to claim 5, characterized in that: An inner discharge channel (55) is provided on the drill tube (52) at a position corresponding to the bypass flow channel (35), an outer discharge channel (53) is provided on the drill tube (52) at a position corresponding to the gap between the double-walled driving rod (3) and the transmission seat (5), and a pressure detection valve (54) is fixedly mounted in the outer discharge channel (53).

7. The drilling device for thick limestone flooded areas on the coal seam floor according to claim 6, characterized in that: The screw motor (4) comprises a driving cylinder (41) rotatably mounted inside the boost flow channel (32), and outer driving blades (42) are evenly arranged on the outer side wall of the driving cylinder (41) along the circumferential direction, inner driving blades (43) are evenly arranged on the inner side wall of the driving cylinder (41) along the circumferential direction, and guide grooves (44) are evenly opened on the outer side wall of the driving cylinder (41).

8. The drilling device for thick limestone flooded areas on the coal seam floor according to claim 7, characterized in that: The flow direction control component (6) comprises a plugging head (61) slidably mounted inside the transmission cylinder (51); a pressure plate (63) is slidably mounted inside the drill cylinder (52); the plugging head (61) and the pressure plate (63) are connected via a connecting rod (62); a pressure spring (64) is provided on one side of the pressure plate (63) close to the plugging head (61); the other end of the pressure spring (64) is fixed to the inner wall of the drill cylinder (52); and a transverse through-flow guide hole (65) is provided on the plugging head (61).

9. The drilling device for thick limestone flooded areas on coal seam floors according to claim 4, characterized in that: The drill bit (8) is provided with an underflow hole, and the articulated ball head (71) is provided with a transverse fluid channel which connects the drill tube (52) and the underflow hole.

10. A method for drilling in a flood-affected area of ​​a thick layer of limestone on a coal seam floor, the method being implemented by using the device for drilling in a flood-affected area of ​​a thick layer of limestone on a coal seam floor as claimed in claim 8, characterized in that: The specific steps of the drilling method are: S1: First, obtain the thickness of the aquifer to be transformed, including the top aquifer and the bottom aquifer of the coal seam; S2: Then, an exploration and treatment hole extending to the aquifer is drilled on the ground, wherein the exploration and treatment hole includes a straight hole section of the treatment hole and an inclined section of the treatment hole; S3: Then, according to the thickness of the aquifer to be transformed, a branch section is drilled at the tail end of the deflection section of the treatment hole to achieve the initial treatment hole drilling of the aquifer. At the same time, an upward or downward strengthening branch section is independently drilled at a position where the water inrush coefficient of the aquifer is large, thereby completing the design of the aquifer treatment hole distribution network, and then controlling the drill bit (8) to achieve drilling work according to the preset treatment hole distribution network; S4: During normal drilling, the flushing fluid is introduced into the first central flow channel (11) of the double-wall drill pipe (1) through the dual-flow channel water feeder, and then flows into the second central flow channel (31) through the diversion central flow channel (23). Since the aperture of the boosting flow channel (32) gradually decreases, the flushing fluid forms a boosting force inside the boosting flow channel (32), thereby driving the screw motor (4) to rotate, thereby driving the transmission seat (5) and the drill bit (8) to rotate synchronously, and the flushing fluid after driving the screw motor (4) to rotate The flushing liquid is directly introduced into the interior of the transmission tube (51), and then flows into the interior of the drill tube (52) through the guide hole (65), thereby realizing the circulation of the flushing liquid, and facilitating the rock drilling operation by using the flushing liquid when the drill bit (8) rotates. When drilling in the aquifer, the guide assembly (7) is controlled to move, and the drill bit (8) is driven to adjust its angle relative to the transmission seat (5), thereby achieving the function of guiding and driving according to the distribution network of the treatment holes, changing the drilling direction of the drill bit (8), and increasing the drilling range of the drill bit (8).

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