Gas-liquid two-phase coal seam anti-reflection device and method

Abstract

The invention provides a gas-liquid two-phase coal seam anti-reflection device and method.The gas-liquid two-phase coal seam anti-reflection device comprises a drill bit body, a conveying assembly and a gas-liquid injection assembly, the drill bit body comprises a drill bit base and cutting picks, jet drill holes are formed in the drill bit base, and the conveying assembly comprises a first one-way valve, a second one-way valve and a plurality of conveying drill rods; in the extending direction of the conveying drill rod, the conveying drill rod is provided with a gas phase conveying cavity and a liquid phase conveying cavity, the gas phase conveying cavity and the liquid phase conveying cavity both penetrate through the conveying drill rod, the second end of the drill bit base is detachably connected with one end of the conveying drill rod, and the first one-way valve is arranged in the gas phase conveying cavity and is adjacent to one side of the drill bit body. The second one-way valve is arranged in the liquid phase conveying cavity and is adjacent to one side of the drill bit body, and the gas-liquid injection assembly is used for driving the conveying drill rod to drill holes and inputting pressure gas and pressure liquid to the conveying rod body. The gas-liquid two-phase coal seam anti-reflection device has the advantages of being good in anti-reflection effect, short in construction period and low in construction cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal seam permeability improvement, in particular to a gas-liquid two-phase coal seam permeability improvement device and method. BACKGROUND

[0002] In a mine with serious gas disasters, gas control is the top priority of mine safety work, and this view has been widely accepted. The coal seam permeability of some mines is poor, and necessary technical measures need to be taken to increase the permeability of the coal seam, which is called coal seam permeability improvement technology.

[0003] In related technologies, coal seam permeability improvement technology aims to improve the permeability of low-permeability coal seams through physical, chemical or mechanical methods, thereby improving gas extraction efficiency. There are many technical methods for coal seam permeability improvement, such as explosive deep hole pre-splitting blasting permeability improvement technology, carbon dioxide phase change blasting permeability improvement technology, hydrolysis permeability improvement technology and acidification permeability improvement technology, etc. The above-mentioned permeability improvement technologies use single medium for permeability improvement, and require the drill rod to be withdrawn after the drilling operation is completed, and then the permeability improvement operation is carried out. The construction process is relatively complex, the construction period is long, and after the drill rod is withdrawn from the drill hole, sometimes the drill hole collapses, causing the transport channel of the permeability improvement medium to be blocked, resulting in the drill hole being scrapped, making it difficult to complete the permeability improvement operation and increasing the construction cost. SUMMARY

[0004] The present application aims to at least partially solve one of the technical problems in the related art.

[0005] To this end, an embodiment of the present application proposes a gas-liquid two-phase coal seam permeability improvement device and method, which has the advantages of good permeability improvement effect, short construction period and low construction cost.

[0006] The gas-liquid two-phase coal seam permeability improvement device according to an embodiment of the present application comprises:

[0007] A drill bit body comprising a drill bit base and a cutting tooth, the cutting tooth being connected to the first end of the drill bit base, the drill bit base being provided with a jet drill hole, the first end of the jet drill hole being located on the side wall of the drill bit base, and the second end of the jet drill hole being located on the second end of the drill bit base;

[0008] The conveying assembly comprises a first one-way valve, a second one-way valve and a plurality of conveying drill rods, the conveying drill rods are detachably connected in sequence in the length direction of the conveying drill rods, the conveying drill rods are provided with a gas phase conveying cavity and a liquid phase conveying cavity in the extension direction of the conveying drill rods, and the gas phase conveying cavity and the liquid phase conveying cavity are arranged through the conveying drill rods, the second end of the drill bit base is detachably connected with one end of the conveying drill rod, the first one-way valve is arranged in the gas phase conveying cavity and adjacent to one side of the drill bit body, and the second one-way valve is arranged in the liquid phase conveying cavity and adjacent to one side of the drill bit body.

[0009] The gas-liquid injection assembly comprises a gas outlet, a liquid outlet and a driving member, the driving member is connected with the conveying drill rod for driving the conveying drill rod to drill, the gas outlet is communicated with the gas phase conveying cavity for inputting pressure gas into the gas phase conveying cavity, and the liquid outlet is communicated with the liquid phase conveying cavity for conveying pressure liquid into the liquid phase conveying cavity.

[0010] The gas-liquid two-phase coal seam permeability improvement device can form radial annular cracks in the coal seam through the injection of gas-liquid two-phase fluid, and effectively increase the permeability of the coal seam. The drill rod can perform permeability improvement operation without withdrawing from the drill hole, avoiding the risks of drill hole collapse and blockage of permeability improvement medium conveying channel. That is, the drill rod is rotated in situ, so that the gas can further expand the cracks along the crack trajectory formed by the liquid cutting, improve the permeability improvement effect, reduce the construction period and reduce the construction cost.

[0011] In some embodiments, the jetting drill hole comprises a first hole section and a second hole section connected in sequence, the first hole section is located adjacent to the cutting tooth on one side of the drill bit base, and the extension direction of the first hole section has an included angle with the extension direction of the second hole section.

[0012] In some embodiments, in the extension direction of the conveying drill rod, the drill bit base comprises a connecting portion and a jetting portion, the connecting portion is connected with one end of the conveying drill rod, the first hole section is located in the jetting portion, and the second end is located in the connecting portion.

[0013] In some embodiments, in the direction pointed by the drill bit base to the cutting tooth, the cross-sectional area of the jetting portion gradually decreases.

[0014] In some embodiments, the first hole section is a plurality of, and the plurality of first hole sections are arranged in a circumferential direction along the center line of the drill bit body.

[0015] In some embodiments, the cutting tooth is a plurality of, and the plurality of cutting teeth are arranged in a circumferential direction along the center line of the drill bit body, and at least one first hole section is arranged between two adjacent cutting teeth.

[0016] In some embodiments, the cross-sectional profile of the gas phase conveying cavity is a circular ring shape, and the gas phase conveying cavity surrounds the liquid phase conveying cavity in a circumferential direction.

[0017] In some embodiments, the second end of the conveying drill rod is provided with a convex ring, a side wall of the convex ring and a side wall of the second end of the conveying drill rod define a communication cavity, the gas phase conveying cavities of two adjacent conveying drill rods are communicated through the communication cavity, and the liquid phase conveying cavities of two adjacent conveying drill rods are communicated through the convex ring.

[0018] In some embodiments, the conveying assembly further comprises a sealing ring, the sealing ring is connected to the convex ring, and the sealing ring is matched with the convex ring.

[0019] The gas-liquid two-phase coal seam permeability improvement method of the embodiment of the present application is completed by using the gas-liquid two-phase coal seam permeability improvement device of any one of the above embodiments, and comprises the following steps:

[0020] The coal seam distribution is analyzed to determine the drilling position;

[0021] The drilling hole is constructed to the coal seam;

[0022] When the drill bit body reaches the permeability improvement position of the coal seam, the drilling hole is cleaned, at this time, the gas pressure input into the drilling hole is not lower than the opening pressure of the first one-way valve, after the coal residue in the drilling hole is completely removed, the gas injection is stopped, and the gas one-way valve is automatically closed;

[0023] The pressure liquid is injected into the conveying drill rod, the pressure liquid cuts the coal seam in a radial direction, the drill rod is slowly rotated by the drilling machine, at this time, the drill rod is only rotated but not drilled forward, when the drill rod is axially rotated for 20-30 turns, the radial annular cracks are formed in the coal seam, at this time, the liquid injection system is stopped, the second one-way valve is automatically closed, and the drilling machine is not stopped;

[0024] The pressure gas is injected again, and the drill rod is rotated in situ, the coal seam is cut again along the crack track formed by the liquid cutting, and the cracks are expanded;

[0025] The drilling hole is cleaned and the liquid in the drilling hole is removed, and a permeability improvement cycle is formed. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a use state schematic diagram of the gas-liquid two-phase coal seam permeability improvement device of the embodiment of the present application.

[0027] Figure 2 is a three-dimensional structure schematic diagram of the drill bit body of the gas-liquid two-phase coal seam permeability improvement device of the embodiment of the present application.

[0028] Figure 3is a cross-sectional structure schematic diagram of a drill bit body of a gas-liquid two-phase coal seam permeability improvement device according to an embodiment of the present application.

[0029] Figure 4 is a cross-sectional structure schematic diagram of a delivery drill rod of a gas-liquid two-phase coal seam permeability improvement device according to an embodiment of the present application.

[0030] Figure 5 is a three-dimensional structure schematic diagram of a delivery drill rod of a gas-liquid two-phase coal seam permeability improvement device according to an embodiment of the present application.

[0031] Reference signs:

[0032] 100, coal seam, 200, fracture, 300, borehole,

[0033] 1, drill bit body, 11, drill bit base, 111, connecting part, 112, injection part, 12, cutting tooth, 13, injection borehole, 131, first hole section, 132, second hole section,

[0034] 2, delivery assembly, 21, first one-way valve, 22, second one-way valve, 23, delivery drill rod, 231, gas phase delivery cavity, 232, liquid phase delivery cavity, 24, convex ring, 25, sealing ring, 26, communication cavity,

[0035] 3, gas-liquid injection assembly, 31, driving member, 32, liquid injection system, 321, high-pressure liquid injection pump, 322, high-pressure liquid hose, 33, gas injection system, 331, high-pressure gas injection pump, 332, high-pressure gas hose. DETAILED DESCRIPTION

[0036] Embodiments of the present application are described in detail below with reference to the accompanying drawings. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0037] A gas-liquid two-phase coal seam permeability improvement device according to an embodiment of the present application is described below with reference to the accompanying drawings.

[0038] As shown in the drawings, Figures 1-5 the gas-liquid two-phase coal seam permeability improvement device according to an embodiment of the present application comprises a drill bit body 1, a delivery assembly 2, and a gas-liquid injection assembly 3.

[0039] The drill bit body 1 comprises a drill bit base 11 and a cutting tooth 12, the cutting tooth 12 being connected to a first end of the drill bit base 11, the drill bit base 11 being provided with an injection borehole 13, a first end of the injection borehole 13 being located at a side wall of the drill bit base 11, and a second end of the injection borehole being located at a second end of the drill bit base 11.

[0040] Specifically, as shown in the drawings, Figures 1-5As shown, the drill bit base 11 is connected with the cutting pick 12 used for cutting coal body, and the side wall of the drill bit base 11 is provided with the jetting borehole 13. The jetting borehole 13 can effectively jet into the coal seam 100 by using the high-pressure gas-liquid two-phase fluid, thereby manufacturing the crack 200.

[0041] The conveying assembly 2 comprises a first one-way valve 21, a second one-way valve 22 and a plurality of conveying drill rods 23, which are detachably connected in sequence in the length direction of the conveying drill rods 23. In the extension direction (e.g. left-right direction in the figure) of the conveying drill rods 23, the conveying drill rods 23 are provided with a gas-phase conveying cavity 231 and a liquid-phase conveying cavity 232, and the gas-phase conveying cavity 231 and the liquid-phase conveying cavity 232 are arranged through the conveying drill rods 23. The second end of the drill bit base 11 is detachably connected with one end of the conveying drill rod 23. The first one-way valve 21 is arranged in the gas-phase conveying cavity 231 and adjacent to one side of the drill bit body 1. The second one-way valve 22 is arranged in the liquid-phase conveying cavity 232 and adjacent to one side of the drill bit body 1. Figure 1

[0042] Specifically, as shown in the figure, the drill bit base 11 is connected with the first end of one conveying drill rod 23 by means of threaded connection, which is convenient for installation and disassembly. The second end of the conveying drill rod 23 is also connected with the first end of another conveying drill rod 23 by means of threaded connection. In this way, a plurality of conveying drill rods 23 can be connected in sequence, so as to be applicable to different coal seams 100 and realize the length arrangement of the borehole 300. Figures 1-5

[0043] It can be understood that, in the conveying drill rod 23 connected with the drill bit base 11, the first one-way valve 21 is arranged in the gas-phase conveying cavity 231 and adjacent to the drill bit base 11. Similarly, the second one-way valve 22 is arranged in the liquid-phase conveying cavity 232 of the conveying drill rod 23 and adjacent to the drill bit base 11. When pressure medium is input into the gas-phase conveying cavity 231 or the liquid-phase conveying cavity 232, the first one-way valve 21 and the second one-way valve 22 can be automatically opened or closed according to the size of the input pressure medium, so that the gas and the liquid can be independently input and the pressure can be adjusted, which is convenient for controlling the permeability improvement process. The first one-way valve 21 can be a gas one-way valve, and the second one-way valve 22 can be a liquid one-way valve.

[0044] The gas-liquid injection assembly 3 comprises a gas outlet, a liquid outlet and a driving member 31 connected with the conveying drill rod 23 for driving the conveying drill rod 23 to drill the borehole 300. The gas outlet is in communication with the gas-phase conveying cavity 231 for inputting pressure gas into the gas-phase conveying cavity 231. The liquid outlet is in communication with the liquid-phase conveying cavity 232 for inputting pressure liquid into the liquid-phase conveying cavity 232.

[0045] ​​It can be understood that the gas-liquid injection assembly 3 comprises a liquid injection system 32 and a gas injection system 33, the liquid injection system 32 comprises a high-pressure liquid injection pump 321 and a high-pressure liquid hose 322, and the gas injection system 33 comprises a high-pressure gas injection pump 331 and a high-pressure gas hose 332.

[0046] It should be noted that the liquid-phase conveying cavity 232 of the conveying drill rod 23 is injected with fracturing fluid or clean water with a certain pressure, the high-pressure liquid injection pump 321 is connected with the liquid-phase conveying cavity 232 through the high-pressure liquid hose 322, so as to cut the coal body and form the radially distributed cracks 200 in the coal seam 100; the system is composed of a plunger pump, a hydraulic transmission box, a motor, an electric control cabinet, a remote operation table and a remote video monitoring table, and the output pressure can reach 30-70 MPa, and the flow range is 100-1000 L / min.

[0047] The gas injection system 33 injects air or carbon dioxide into the gas-phase conveying cavity 231 of the conveying drill rod 23 through the high-pressure gas hose 332, so as to expand the cracks 200 formed by liquid cutting; the system is composed of a gas compression device, a gas injection pump, a monitoring device, an electric control cabinet, a remote operation table and the like, and a carbon dioxide storage tank needs to be additionally arranged when carbon dioxide is used as the medium; the output pressure can reach 1-30 MPa, and the flow range is 500-1000 m3 / h.

[0048] That is, the gas-liquid two-phase coal seam permeability improvement device of the embodiment can form the radially annular cracks 200 in the coal seam 100 through the injection of the gas-liquid two-phase fluid, and effectively improve the permeability of the coal seam 100. The drill rod does not need to be withdrawn from the borehole 300 to perform the permeability improvement operation, and the risks of borehole collapse and blockage of the permeability improvement medium conveying channel are avoided. That is, the drill rod is rotated in situ, so that the gas can further expand the cracks 200 along the track of the cracks 200 formed by liquid cutting, the permeability improvement effect is improved, the construction period is reduced, and the construction cost is reduced.

[0049] In some embodiments, the jetting borehole 13 comprises a first hole section 131 and a second hole section 132 connected in sequence, the first hole section 131 is located on the side of the drill bit base 11 adjacent to the cutting tooth 12, and the first hole section 131 has an included angle between the extension direction and the extension direction of the second hole section 132.

[0050] Specifically, as shown in Figures 1-5 the first hole section 131 is located on the side of the drill bit base 11 adjacent to the cutting tooth 12. That is, the port at one end of the first hole section 131 is located on the side wall of the drill bit base 11 and is arranged towards the wall surface of the borehole 300. The other end of the first hole section 131 is connected with one end of the second hole section 132, and the other end of the second hole section 132 is in communication with the gas-phase conveying cavity 231 and the liquid-phase conveying cavity 232 of the conveying drill rod 23.

[0051] It can be understood that the extension direction of the second hole section 132 and the extension direction of the first hole section 131 have an included angle, so that the jet drilling hole 13 has a certain bending in its extension direction, which ensures that the jet drilling hole 13 can spray gas or liquid towards the wall surface of the drilling hole 300.

[0052] In some embodiments, in the extension direction of the conveying drill rod 23, the drill bit base 11 comprises a connecting part 111 and a jet part 112, the connecting part 111 is connected to one end of the conveying drill rod 23, and the first hole section 131 is located in the jet part 112, and the second end is located in the connecting part 111.

[0053] Specifically, as shown in Figures 1-5 , the connecting part 111 is located at the right end of the drill bit base 11 and connected to the left end of the conveying drill rod 23. The main function of the connecting part 111 is to ensure the reliable connection between the drill bit base 11 and the conveying drill rod 23, and to ensure the transmission of power and fluid during drilling and penetration improvement. The jet part 112 is located at the left end of the drill bit base 11, and the first hole section 131 is arranged inside the jet part 112. The design of the jet part 112 enables the gas-liquid two-phase fluid to be effectively sprayed out of the jet drilling hole 13, and the coal seam 100 is cut and broken.

[0054] In some embodiments, in the direction pointing to the cutting tooth 12 by the drill bit base 11, the cross-sectional area of the jet part 112 gradually decreases.

[0055] It can be understood that the longitudinal cross-sectional area of the jet part 112 gradually decreases in the direction from right to left. That is, the cross-sectional area of the connecting part 111 gradually decreases, which helps to reduce the risk of the jet drilling hole 13 being blocked by the coal seam 100 drilling hole 300, and ensures that the fluid can be effectively sprayed into the coal seam 100. The jet angle and distance are optimized, that is, by adjusting the cross-sectional area of the connecting part 111, the jet angle and distance can be optimized, so that the fluid can be sprayed into the coal seam 100 at the best angle and distance, and the cutting effect is improved.

[0056] In some embodiments, the first hole section 131 is a plurality of, and the plurality of first hole sections 131 are arranged in a circumferential direction along the center line of the drilling hole 300 body.

[0057] Specifically, as shown in Figures 1-5 , the first hole section 131 is a plurality of, the second hole section 132 is one, and the plurality of first hole sections 131 are connected to the second hole section 132, so that when the connecting part 111 is connected to the conveying rod body, the gas phase conveying cavity 231 and the liquid phase conveying cavity 232 are connected to the second hole section 132.

[0058] It can be understood that the design of the plurality of jetting drill holes 13 enables the gas-liquid two-phase fluid to form multiple directional fractures 200 in the coal seam 100, enhancing the cutting and crushing effect and improving the permeability effect. The jetting drill holes 13 arranged circumferentially along the center line of the drill bit base 11 can enable the fluid to be jetted into the coal seam 100 from multiple angles, further optimizing the jetting angle and improving the cutting effect. The uniform arrangement of the jetting drill holes 13 helps to avoid jetting blind areas and ensure that the entire coal seam 100 can be effectively cut and crushed. The design of the plurality of jetting drill holes 13 helps to enhance the diffusion range of the fluid, making the cutting effect more uniform and effective.

[0059] In some embodiments, the plurality of cutting teeth 12 are arranged circumferentially along the center line of the drill bit body 1, and at least one first hole section 131 is arranged between any two adjacent cutting teeth 12.

[0060] Specifically, as shown in Figures 1-5 two adjacent cutting teeth 12 and the jetting part 112 forms a gap area, and the opening of the first hole section 131 of the jetting drill hole 13 is arranged in the gap area, so that the cutting tooth 12 provides certain support for the jetting drill hole 13, and the gap area can also provide jetting drill holes for the jetting drill hole 13, avoiding blockage of the jetting drill hole 13 and ensuring subsequent fracturing effect.

[0061] In some embodiments, the cross-sectional profile of the gas phase conveying cavity 231 is a circular ring, and the gas phase conveying cavity 231 is arranged circumferentially around the liquid phase conveying cavity 232.

[0062] It can be understood that the circular ring cross-sectional profile of the gas phase conveying cavity 231 can provide a larger fluid conveying area, thereby improving the conveying efficiency of the gas. The circumferential arrangement of the gas phase conveying cavity 231 around the liquid phase conveying cavity 232 helps to effectively separate the gas and the liquid during the conveying process, reduces the gas-liquid mixing, and improves the conveying efficiency of each other.

[0063] That is, the circular ring cross-sectional profile provides a larger fluid conveying area, which helps the gas to flow more smoothly during the conveying process, reduces the resistance, and improves the conveying efficiency. The circumferential arrangement of the gas phase conveying cavity 231 around the liquid phase conveying cavity 232 enables the gas and the liquid to occupy independent channels during the conveying process, effectively reducing the possibility of gas-liquid mixing.

[0064] In some embodiments, the second end of the conveying drill rod 23 is provided with a convex ring 24, the side wall of the convex ring 24 and the side wall of the second end of the conveying drill rod 23 define a communication cavity 26, the gas phase conveying cavities 231 of the adjacent two conveying drill rods 23 are communicated through the communication cavity 26, and the liquid phase conveying cavities 232 of the adjacent two conveying drill rods 23 are communicated through the convex ring 24.

[0065] Specifically, as shown inFigures 1-5 As shown, the outer side wall of the convex ring 24 and the inner side wall of the second end of the conveying drill rod 23 define a communication cavity 26. When the two conveying drill rods 23 are connected, the gas phase conveying cavity 231 is annular, and the communication cavity 26 is also annular. Therefore, the gas phase conveying cavity 231 and the liquid phase conveying cavity 232 of the two connected conveying drill rods 23 can be better communicated through the annular communication cavity 26, so as to ensure the communication state of the corresponding cavities.

[0066] It can be understood that the adjacent gas phase conveying cavities 231 can be connected through the communication cavity 26, so as to ensure the stability of the connected structure and prevent deformation or damage during the conveying process.

[0067] Preferably, the cross-sectional area of the communication cavity 26 gradually decreases in the direction of the flow of the pressure medium. That is, the communication cavity 26 is arranged in a tapered structure, so that the fluid flowing through the communication cavity 26 can increase the flow rate and pressure of the fluid, enhance the cutting strength on the coal seam 100, and improve the permeability effect.

[0068] In some embodiments, the conveying assembly 2 further comprises a sealing ring 25 connected with the convex ring 24, and the sealing ring 25 is matched with the convex ring 24.

[0069] It can be understood that the main function of the sealing ring 25 is to ensure the sealing between the gas phase conveying cavity 231 and the liquid phase conveying cavity 232 during the connection process, so as to prevent the leakage of the gas-liquid two-phase fluid at the connection position. The profile of the sealing ring 25 is matched with the profile of the convex ring 24, so as to avoid the problem that the sealing ring 25 is bent due to extrusion when the two conveying drill rods 23 are connected. The design can ensure the close matching between the sealing ring 25 and the convex ring 24, so as to form a good sealing effect.

[0070] Preferably, the sealing ring 25 can be made of a material with a deformation function, such as soft rubber.

[0071] Optionally, the end surface of the convex ring 24 is provided with a groove, and part of the sealing ring 25 is arranged in the groove, so as to prevent the sealing ring 25 from being extruded during the installation process and causing a gap between the sealing ring 25 and the convex ring 24, and to ensure the sealing between the sealing ring 25 and the convex ring 24.

[0072] The gas-liquid two-phase coal seam permeability improvement method of the embodiment of the present application is described below.

[0073] The gas-liquid two-phase coal seam permeability improvement method of the embodiment of the present application is completed by using the gas-liquid two-phase coal seam 100 permeability improvement device of any one of the above embodiments, and the method comprises the following steps.

[0074] The distribution of the coal seam 100 is analyzed to determine the position of the borehole 300. It can be understood that, for the analysis of the structure of the coal seam 100, a geological exploration device such as a geophysical logging instrument, a coal seam 100 detection radar, etc. is required to analyze the distribution of the coal seam 100. The position of the borehole 300 is ensured to be properly selected to avoid unnecessary waste of resources and construction risks.

[0075] The borehole 300 is constructed to the coal seam 100. It can be understood that the borehole 300 is drilled by using the gas-liquid two-phase coal seam 100 permeability improvement device in the above embodiment.

[0076] The drill bit body 1 reaches the permeability improvement position of the coal seam 100, and the borehole 300 is cleaned. At this time, the gas pressure input into the borehole 300 is not lower than the opening pressure of the first one-way valve 21. After the coal residue in the borehole 300 is completely removed, the gas injection is stopped, and the gas one-way valve is automatically closed.

[0077] It can be understood that the gas injection system 33 is started, and air or carbon dioxide is injected into the borehole 300 through the gas phase conveying cavity 231, and the pressure is not lower than the opening pressure of the first one-way valve 21. By using the pressure higher than the first one-way valve 21, the coal residue in the borehole 300 can be effectively removed to create conditions for subsequent permeability improvement operations.

[0078] The pressure liquid is injected into the conveying drill rod 23, the pressure liquid cuts the coal seam 100 along the radial direction of the borehole 300, and the drilling machine is started to slowly rotate the drill rod. At this time, the drill rod only rotates but does not drill forward, and when the drill rod is axially rotated for 20-30 turns, the radial annular crack 200 is formed in the coal seam 100. At this time, the liquid injection system 32 is stopped, the second one-way valve 22 is automatically closed, and the drilling machine is not stopped.

[0079] It can be understood that the liquid injection system 32 is started, and the fracturing fluid or clean water is injected into the borehole 300 through the liquid phase conveying cavity 232. The high-pressure liquid cuts the coal seam 100 along the radial direction of the borehole 300 to form the crack 200. Among them, the drilling machine rotates the conveying drill rod 23 at a low speed, but does not axially feed. By rotating the drill rod, the high-pressure liquid forms the radial annular crack 200 in the coal seam 100 to improve the permeability effect.

[0080] In addition, the liquid injection system 32 is stopped, the second one-way valve 22 is automatically closed, and the drilling machine remains in the rotating state. After ensuring that the crack 200 is formed, the liquid cannot flow back, and at the same time, the drilling machine continues to rotate to prepare for the next step.

[0081] The pressure gas is injected again, and the drill pipe is rotated in situ to cut the coal bed 100 again along the trajectory of the crack 200 formed by the liquid cutting, to expand the crack 200. It can be understood that the gas injection system 33 is started again to inject air or carbon dioxide into the borehole 300 through the gas phase conveying cavity 231. The high-pressure gas is used to further expand the crack 200 along the trajectory of the crack 200 formed by the liquid cutting, to enhance the permeability enhancement effect.

[0082] It should be noted that the high-pressure liquid can effectively form a preliminary crack 200 network in the coal bed 100, providing a path for subsequent high-pressure gas cutting. Liquid cutting can reduce the demand for high-pressure gas, because the liquid has completed most of the cutting work, and the high-pressure gas is mainly used to expand and deepen the cracks 200. The liquid has good cooling and lubricating effect, which can reduce the wear of the drill bit and improve the service life and cutting efficiency of the drill bit. The liquid is more stable than the gas, reducing the risk of safety accidents such as gas leakage or explosion.

[0083] The borehole 300 is cleaned and the liquid in the borehole 300 is discharged to form a permeability enhancement cycle. It can be understood that the borehole 300 can also be cleaned and the liquid can be discharged by using the gas injection system 33 to operate in a low-pressure state. Ensure that the borehole 300 is clean and ready for the next permeability enhancement cycle.

[0084] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0085] In addition, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0086] In the present application, unless specifically defined otherwise, the terms "mounting", "connected", "connecting", "fixed", "fixedly connected", "connection", "fixedly connected", "connected", "fixed", and the like should be construed broadly, for example, can be fixed connection, can be detachable connection, or integral; can be mechanical connection, can be electrical connection or communication with each other; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically defined. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0087] In the present application, unless specifically defined otherwise, the first feature is "on" or "under" the second feature. The first and second features can be in direct contact, or the first and second features can be in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0088] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in the specification and the features of different embodiments or examples without contradiction.

[0089] Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A gas-liquid two-phase coal seam permeability enhancement device, characterized in that: include: A drill bit body, the drill bit body comprising a drill bit base and a pick, the pick being connected to a first end of the drill bit base, the drill bit base defining a jet drill hole, the first end of the jet drill hole being located on a side wall of the drill bit base, and the second end of the jet drill hole being located on a second end of the drill bit base; A conveying assembly, the conveying assembly comprising a first one-way valve, a second one-way valve, and a plurality of conveying drill rods, the plurality of conveying drill rods being detachably connected in sequence along their length direction, the conveying drill rods being provided with a gas conveying cavity and a liquid conveying cavity in the extending direction of the conveying drill rods, and the gas conveying cavity and the liquid conveying cavity both being arranged through the conveying drill rods, the second end of the drill bit base being detachably connected to one end of the conveying drill rods, the first one-way valve being provided in the gas conveying cavity and adjacent to one side of the drill bit body, and the second one-way valve being provided in the liquid conveying cavity and adjacent to one side of the drill bit body; A gas-liquid injection assembly includes a gas outlet, a liquid outlet and a driving member. The driving member is connected to the delivery drill rod to drive the delivery drill rod to drill a hole. The gas outlet is connected to the gas phase delivery chamber to input pressurized gas into the gas phase delivery chamber. The liquid outlet is connected to the liquid phase delivery chamber to deliver pressurized liquid into the liquid phase delivery chamber.

2. The gas-liquid two-phase coal seam permeability enhancement device according to claim 1, characterized in that: The jet drilling hole includes a first hole segment and a second hole segment connected in sequence. The first hole segment is located on the side of the drill bit base adjacent to the pick. An angle is formed between the extending directions of the first hole segment and the second hole segment.

3. The gas-liquid two-phase coal seam permeability enhancement device according to claim 2, characterized in that: In the extension direction of the delivery drill rod, the drill bit base includes a connecting portion and an injection portion, the connecting portion is connected to one end of the delivery drill rod, the first hole section is located in the injection portion, and the second end is located in the connecting portion.

4. The gas-liquid two-phase coal seam permeability enhancement device according to claim 3, characterized in that: The cross-sectional area of ​​the injection portion gradually decreases in a direction from the drill base to the cutting tooth.

5. The gas-liquid two-phase coal seam permeability enhancement device according to claim 4, characterized in that: There are a plurality of first hole sections, and the plurality of first hole sections are arranged at intervals along the circumferential direction of the center line of the drill body.

6. The gas-liquid two-phase coal seam permeability enhancement device according to claim 5, characterized in that: There are a plurality of picks, which are arranged at intervals along the circumference of the center line of the drill bit body, and at least one first hole segment is arranged between two adjacent picks.

7. The gas-liquid two-phase coal seam permeability enhancement device according to any one of claims 1 to 6, characterized in that: The cross-sectional profile of the gas phase delivery cavity is annular, and the gas phase delivery cavity is arranged circumferentially around the liquid phase delivery cavity.

8. The gas-liquid two-phase coal seam permeability enhancement device according to claim 7, characterized in that: The second end of the delivery drill rod is provided with a convex ring, and the side wall of the convex ring and the side wall of the second end of the delivery drill rod define a connecting cavity. The gas phase delivery cavities of two adjacent delivery drill rods are connected through the connecting cavity, and the liquid phase delivery cavities of two adjacent delivery drill rods are connected through the convex ring.

9. The gas-liquid two-phase coal seam permeability enhancement device according to claim 8, characterized in that: The conveying component further includes a sealing ring, which is connected to the convex ring and adapted to the convex ring.

10. A gas-liquid two-phase coal seam permeability enhancement method, the gas-liquid two-phase coal seam permeability enhancement method being performed using the gas-liquid two-phase coal seam permeability enhancement device according to any one of claims 1 to 9, characterized in that: The following steps are involved: Analyze the distribution of coal seams and determine the drilling location; Drilling into coal seams; The drill bit reaches the permeability enhancement position of the coal seam and cleans the borehole. At this time, the gas pressure input into the borehole is not lower than the opening pressure of the first one-way valve. After the coal slag in the borehole is completely removed, the gas injection is stopped and the gas one-way valve automatically closes. Inject pressurized liquid into the delivery drill pipe, which cuts the coal seam along the radial direction of the borehole. Start the drill rig and slowly rotate the drill pipe. The drill pipe only rotates but does not drill forward. After the drill pipe rotates axially 20 to 30 times, radial annular cracks are formed in the coal seam. At this time, the liquid injection system is stopped, the second one-way valve automatically closes, and the drilling rig does not stop. The pressurized gas is injected again, and the drill pipe is rotated in situ, and the coal seam is cut again with pressurized gas along the fracture track formed by the liquid cutting to expand the fracture; The borehole is cleaned and the liquid in the borehole is drained to form an anti-reflection cycle.

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