PERMEABILITY ENHANCEMENT DEVICE FOR COAL-SEAM GAS DRAINAGE

Abstract

A high-efficiency permeability enhancement device for coal-seam gas drainage, wherein, including: a high-pressure gas cylinder, an air compressor being connected to a gas outlet of the high-pressure gas cylinder, a drill pipe, a plurality of jet nozzles being evenly disposed in a circumferential direction of the drill pipe, located below a drill bit, arranged outwards along a radial direction of the drill pipe, and in communication with the gas outlet of the high-pressure gas cylinder; and a plurality of self-driving drill bits being evenly disposed in the circumferential direction of the drill pipe, and located below the jet nozzles, wherein an end of the drill pipe is provided with the drill bit, a front end of the self-driving drill bits is radially defined with a plurality of front spray holes, and the self-driving drill bits are in communication with the gas outlet of the high-pressure gas cylinder.

Claims

1. A permeability enhancement device for coal-seam gas drainage, wherein, comprising: a high-pressure gas cylinder, an air compressor, a drill pipe, jet nozzles, and self-driving drill bits; the high-pressure gas cylinder is configured to store a gas medium; and the air compressor is connected to a gas outlet of the high-pressure gas cylinder, and is configured to pressurize the gas medium in the high-pressure gas cylinder; and an end of the drill pipe is provided with a drill bit; and a plurality of the jet nozzles are evenly disposed in a circumferential direction of the drill pipe, and the jet nozzles are located below the drill bit, the jet nozzles are arranged outwards along a radial direction of the drill pipe, and the jet nozzles are in communication with the gas outlet of the high-pressure gas cylinder; and a plurality of the self-driving drill bits are evenly disposed in the circumferential direction of the drill pipe, and the self-driving drill bits are located below the jet nozzles, a front end of the self-driving drill bits is radially defined with a plurality of front spray holes, and the self-driving drill bits are in communication with the gas outlet of the high-pressure gas cylinder; and the gas outlet of the high-pressure gas cylinder is connected with a self-driving manifold, the self-driving manifold is provided with a self-driving gas supply valve, which is configured for controlling an on-off of the self-driving manifold; and the self-driving manifold is connected with a plurality of self-driving branch pipes, each self-driving branch pipe is correspondingly connected to at least one self-driving drill bit, and an air is supplied to the self-driving drill bits through the self-driving branch pipes; and the self-driving drill bits comprise a high-pressure hose and a nozzle, one end of the high-pressure hose is in communication with the self-driving branch pipes, and an other end of the high-pressure hose is in communication with the nozzle; a plurality of the front spray holes are radially defined at the front end of the nozzle.

2. The permeability enhancement device for coal-seam gas drainage according to claim 1, wherein, the gas outlet of the high-pressure gas cylinder is connected with a jet manifold, and the jet manifold is provided with a jet gas supply valve, which is configured for controlling the on-off of the jet manifold.

3. The permeability enhancement device for coal-seam gas drainage according to claim 2, wherein, the jet manifold is connected with a plurality of jet branch pipes, each jet branch pipe is correspondingly connected to one jet nozzle, and the air is supplied to the jet nozzles through the jet branch pipes.

4. The permeability enhancement device for coal-seam gas drainage according to claim 3, wherein, both the jet branch pipes and the self-driving branch pipes are located inside the drill pipe, and a plurality of the self-driving branch pipes are located at a periphery of the plurality of the jet branch pipes.

5. The permeability enhancement device for coal-seam gas drainage according to claim 1, wherein, a rear end of the nozzle is defined with a rear spray hole, which is inclined towards the high-pressure hose; and a middle part of the nozzle is defined with a lateral spray hole, which is located between the front spray holes and the rear spray hole, and an orientation of the lateral spray hole is perpendicular to an axis of the nozzle.

6. The permeability enhancement device for coal-seam gas drainage according to claim 5, wherein, the permeability enhancement device for coal-seam gas drainage further comprises a supercritical carbon dioxide generation device, which is in communication with the high-pressure gas cylinder, and is configured to supply a supercritical carbon dioxide gas to the high-pressure gas cylinder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which form a part of the present disclosure, are intended to provide a further understanding of the present disclosure, and the schematic embodiment of the present disclosure and the description thereof are intended to explain the present disclosure, and do not constitute an unduly limiting of the present disclosure. Wherein:

[0031] FIG. 1 is a structure schematic diagram of a high-efficiency permeability enhancement device for coal-seam gas drainage according to an embodiment of the present disclosure;

[0032] FIG. 2 is a flowchart of a high-efficiency permeability enhancement method for coal-seam gas drainage according to an embodiment of the present disclosure;

[0033] FIG. 3 is a cross-sectional view at point A in FIG. 1 according to an embodiment of the present disclosure;

[0034] FIG. 4 is a cross-sectional view at point B in FIG. 1 according to an embodiment of the present disclosure;

[0035] FIG. 5 is a cross-sectional view at point C in FIG. 1 according to an embodiment of the present disclosure;

[0036] FIG. 6 is a structure schematic diagram of self-driving drill bits according to an embodiment of the present disclosure.

LABELS AND DESCRIPTIONS

[0037] 1drill bit; 2jet nozzle; 3self-driving drill bit; 4lateral spray hole; 5drill pipe; 6jet gas supply valve; 7self-driving gas supply valve; 8high-pressure gas cylinder; 9supercritical carbon dioxide generation device; 10air compressor; 11jet branch pipe; 12self-driving branch pipe; 13high-pressure hose; 14rear spray hole; 15nozzle; 16front spray hole.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] According to a specific embodiment of the present disclosure, as shown in FIGS. 1-6, the present disclosure provides a high-efficiency permeability enhancement device for coal-seam gas drainage, which includes: a high-pressure gas cylinder 8, an air compressor 10, a drill pipe 5, jet nozzles 2, and self-driving drill bits 3.

[0039] The high-pressure gas cylinder 8 is used to store a gas medium.

[0040] The air compressor 10 is connected to a gas outlet of the high-pressure gas cylinder 8, and is used to pressurize the gas medium in the high-pressure gas cylinder 8.

[0041] An end of the drill pipe 5 is provided with a drill bit 1.

[0042] A plurality of the jet nozzles 2 are evenly disposed in a circumferential direction of the drill pipe 5, and the jet nozzles 2 are located below the drill bit 1, the jet nozzles 2 are arranged outwards along a radial direction of the drill pipe 5, and the jet nozzles 2 are in communication with the gas outlet of the high-pressure gas cylinder 8.

[0043] A plurality of the self-driving drill bits 3 are evenly disposed in the circumferential direction of the drill pipe 5, and the self-driving drill bits 3 are located below the jet nozzles 2, a front end of the self-driving drill bits 3 is radially defined with a plurality of front spray holes 16, and the self-driving drill bits 3 are in communication with the gas outlet of the high-pressure gas cylinder 8.

[0044] One drill hole is drilled in the bottom drainage roadway, the drill pipe 5 of this device is extended into the main drill hole, and a high-pressure air is sprayed onto a coal body through the jet nozzles 2 on the drill pipe 5, so as to perform an anhydrous pre-slotting on the coal body. On this basis, a front spray hole 16 is arranged at the front end of the self-driving drill bits 3 to continue spraying the high-pressure air onto the coal body, enabling the self-driving drill bits 3 to drill in a radial direction perpendicular to the main drill hole. Consequently, the coal body is enhanced in permeability circumferentially around the main drill hole, achieving a better permeability enhancement effect on the coal body; this not only reduces the amount of drilling construction workload but also maximizes the gas drainage efficiency.

[0045] The gas outlet of the high-pressure gas cylinder 8 is connected with a jet manifold, and the jet manifold is provided with a jet gas supply valve 6, which is used for controlling the on-off of the jet manifold.

[0046] The jet manifold is connected with a plurality of jet branch pipes 11, each jet branch pipe 11 is correspondingly connected to one jet nozzle 2, and the air is supplied to the jet nozzles 2 through the jet branch pipes.

[0047] In the embodiment of the present disclosure, eight jet nozzles 2 are provided, and eight jet branch pipes 11 are similarly provided, each jet branch pipe 11 is connected to one jet nozzle 2. Wherein, the direction of an airflow sprayed from the jet nozzles 2 is perpendicular to an axial direction of the drill pipe 5.

[0048] The gas outlet of the high-pressure gas cylinder 8 is connected with a self-driving manifold, the self-driving manifold is provided with a self-driving gas supply valve 7, which is used for controlling an on-off of the self-driving manifold.

[0049] In the embodiment of the present disclosure, the jet manifold and the self-driving manifold are two gas supply branches on the gas outlet of the high-pressure gas cylinder 8. By providing the jet gas supply valve 6 on the jet manifold, and providing the self-driving gas supply valve 7 on the self-driving manifold, two gas supply branches can be used independently without affecting each other.

[0050] The self-driving manifold is connected with a plurality of self-driving branch pipes 12, each self-driving branch pipe 12 is correspondingly connected to at least one self-driving drill bit 3, and the air is supplied to the self-driving drill bits 3 through the self-driving branch pipes 12.

[0051] In the embodiment of the present disclosure, the drill pipe 5 is provided with three layers of the self-driving drill bits 3, with eight self-driving drill bits 3 in each layer. Eight self-driving branch pipes 12 are provided, and each self-driving branch pipe 12 is connected to three self-driving drill bits 3 in the same axial direction, that is, the air is supplied to three self-driving drill holes through each self-driving branch pipe 12.

[0052] Both the jet branch pipes and the self-driving branch pipes are located inside the drill pipe 5, and a plurality of the self-driving branch pipes are located at a periphery of a plurality of the jet branch pipes. In the embodiment of the present disclosure, eight self-driving branch pipes are located around eight jet branch pipes, so as to achieve a more reasonable layout of the pipelines inside the drill pipe 5.

[0053] The self-driving drill bits 3 include a high-pressure hose 13 and a nozzle 15, one end of the high-pressure hose 13 is in communication with the self-driving branch pipes, and an other end of the high-pressure hose 13 is in communication with the nozzle 15; a plurality of the front spray holes 16 are radially defined at the front end of the nozzle 15.

[0054] In the embodiment of the present disclosure, the high-pressure hose 13 can facilitate the free expansion and contraction of the nozzle 15, allowing the nozzle 15 to approach the coal body closely, which further enables the high-pressure gas sprayed from the nozzle 15 to closely approach the coal and break it, greatly improving the coal breaking effect and facilitating the formation of pores in the coal body by the self-driving drill bits 3; a plurality of the front spray holes 16 are radially outwardly defined, so that the high-pressure gas sprayed from the nozzle 15 can exceed the cross-sectional area of the nozzle 15, which further enable the pores formed by the coal breaking of the self-driving drill bits 3 to have a diameter larger than the diameter of the nozzle 15, thereby further facilitating the nozzle 15 to insert into the pores for coal breaking.

[0055] A rear end of the nozzle 15 is defined with a rear spray hole 14, which is inclined towards the high-pressure hose 13; and a middle part of the nozzle 15 is defined with a lateral spray hole 4, which is located between the front spray holes 16 and the rear spray hole 14, and an orientation of the lateral spray hole 4 is perpendicular to an axis of the nozzle 15.

[0056] In the embodiment of the present disclosure, the rear spray hole 14 is inclined towards the high-pressure hose 13, that is, the rear spray hole 14 is inclined towards the rear of the nozzle 15. With this arrangement, when the nozzle 15 is entered into the pores formed by the the self-driving drill bits 3, the front spray hole 16 can break the coal to produce the coal dust. During the advance of the nozzle 15, the rear spray hole 14 can blow the air towards the rear to blow out as much coal dust as possible from the pores, thus aporesing the blockage of the pores; while the lateral spray holes 4 can emit the high-pressure gas along the direction perpendicular to the pore extension, forming the fractures perpendicular to the pores in the pores, which can greatly increase the permeability of the coal body.

[0057] The permeability enhancement device for coal-seam gas drainage further includes a supercritical carbon dioxide generation device 9, which is in communication with the high-pressure gas cylinder 8, and is used to supply a supercritical carbon dioxide gas to the high-pressure gas cylinder 8.

[0058] In the embodiment of the present disclosure, the supercritical carbon dioxide jet has a deep rock-breaking depth and a wide crushing range. Moreover, the threshold pressure for rock-breaking by the supercritical carbon dioxide jet is lower than that of the water jet, achieving better rock-breaking effect. Additionally, it can significantly conserve water resources.

[0059] The present disclosure further provides a permeability enhancement method for coal-seam gas drainage, which utilizes the permeability enhancement device for coal-seam gas drainage as described above, wherein, including the following steps 1-6. [0060] In the step 1, drilling a large-diameter drill hole from a bottom drainage roadway into a coal-seam as a main drill hole. [0061] In the step 2, after the main drill hole is drilled, withdrawing the drill pipe 5 and a drilling tool from the main drill hole; then inserting the drill pipe 5 in the permeability enhancement device for coal-seam gas drainage into the main drill hole. [0062] In the step 3, after the jet nozzles 2 are reached a coal sighting point, starting the air compressor 10 and opening the jet gas supply valve 6; injecting the supercritical carbon dioxide gas into a coal body through the jet nozzles 2; slitting the coal body to achieve preliminary permeability enhancement, which provides a good foundation for the subsequent drilling of the self-driving drill bits 3; in the embodiment of the present disclosure, the slit is cut for ten minutes at each location and advanced every 0. 3 m. [0063] In the step 4, when the drill pipe 5 is moved up to a half of a coal hole, opening the self-driving gas supply valve 7 and adjusting a pressure parameter of the air compressor 10 to make the self-driving drill bits 3 drill into the coal-seam.

[0064] In the embodiment of the present disclosure, when the high-pressure gas medium is introduced into the self-driving drill bits 3, the high-pressure hose 13 is extended straight forward, allowing the nozzle 15 to press against the coal-seam, and the front spray hole 16 on the nozzle 15 sprays the supercritical carbon dioxide to break the coal and form pores, enabling the nozzle 15 to insert into the pores, at this point, the rear spray hole 14 sprays the gas to spray the coal dust from the pores, and the lateral spray hole 4 sprays the high-pressure gas along the extension direction perpendicular to the pore extension, forming the fractures that is perpendicular to the pores within the pores. [0065] In the step 5, after a drilling process and a slotting process of the self-driving drill bits 3 are completed, closing the self-driving gas supply valve 7 and the jet gas supply valve 6, and withdrawing the drill pipe 5 from the main drill hole. [0066] In the step 6, sealing the main drill hole, and connecting a gas drainage pipeline for gas drainage.