CN116241175A

CN116241175A - Drilling construction and coal seam gas extraction method combining rotary cutting and impact permeability improvement

Info

Publication number: CN116241175A
Application number: CN202310110119.3A
Authority: CN
Inventors: 程波; 杨亮; 张仰强
Original assignee: CCTEG Chongqing Research Institute Co Ltd
Current assignee: CCTEG Chongqing Research Institute Co Ltd
Priority date: 2023-02-14
Filing date: 2023-02-14
Publication date: 2023-06-09

Abstract

The invention relates to a drilling construction and coal seam gas extraction method with the cooperation of rotary cutting and impact reflection prevention, which belongs to the technical field of coal mine safety, wherein a drilling machine is adopted to drive a spiral drill rod so as to drive a drill bit at the end part to conduct conventional cutting on a coal body, an impact assembly is arranged in the drill rod at the end part, the impact assembly can push an arc seat through high-pressure air conveyed by an underground air compressor, then a fracturing block is driven to impact the spiral impact drill bit, the spiral impact drill bit is enabled to impact the coal body in front, and a plurality of cracks are generated on the coal body, so that the coal seam permeability is improved, the structural integrity of the coal body is damaged, and the follow-up drilling process is facilitated. And after the drilling construction is finished, plugging the drilling, connecting the drilling with a downhole gas extraction pipeline, and implementing coal seam gas enhanced extraction. The invention has simple structure, less related equipment, obvious technical and economic benefits and can provide solid technical support for the efficient treatment of underground gas disasters of coal mines.

Description

Drilling construction and coal seam gas extraction method combining rotary cutting and impact permeability improvement

Technical Field

The invention belongs to the technical field of coal mine safety, and relates to a drilling construction and coal seam gas extraction method with cooperation of rotary cutting and impact reflection prevention.

Background

Coal mine gas (also called as "coalbed methane") is a combustible gas with methane as a main component, is mainly stored in a pore fracture system of coal in an adsorption and free form, and is one of main threats for coal mine safety production, but is also an unconventional natural gas. The method has the advantages of enhancing gas extraction of the coal mine and exploitation and utilization of coalbed methane in the coal mine area, and has great significance in reducing greenhouse effect, guaranteeing safe production of the coal mine and increasing clean energy supply. However, the coal seam gas geological conditions in China are complex, most of the coal seam gas geological conditions belong to high-gas, coal and gas outburst coal seams, the permeability of coal bodies is low, and high-efficiency gas control is difficult to realize by adopting conventional measures. Therefore, coal mine safety workers often adopt hydraulic fracturing, high-pressure hydraulic slotting, carbon dioxide phase-change fracturing and other processes to implement coal seam permeability improvement after coal seam gas extraction drilling construction is completed, and the aims to improve the gas permeability of a coal body and enhance the gas extraction effect. However, the conventional anti-reflection measure needs to add new special process equipment after drilling construction is completed, and the operation time is long, so that the technical and economic benefits are poor. The synergistic permeability-increasing technology in the drilling construction process is sought, so that the gas extraction drilling construction and permeability-increasing measures complement each other, the mine gas disaster control efficiency is improved, and the method is one of the key technical problems which need to be solved by current coal mine safety and technology workers.

Disclosure of Invention

In view of the above, the present invention aims to provide a drilling construction and coal seam gas extraction method that can solve the above problems by combining rotary cutting and impact reflection enhancement.

In order to achieve the above purpose, the present invention provides the following technical solutions:

a drilling construction and coal seam gas extraction method combining rotary cutting and impact permeability improvement comprises the following steps:

s1: an impact assembly is arranged in the end drill rod, one end of the end drill rod is provided with a rotary cutting drill bit, the other end of the end drill rod is connected with the spiral drill rod, the other end of the spiral drill rod is connected with a water braid, and the other end of the water braid is connected with an air outlet end of an underground coal mine air compressor through a high-pressure rubber tube; erecting a drilling machine at the position of a coal seam gas extraction drilling hole to be constructed in a transportation gate way of a coal mine underground stoping working face, and fixing a spiral drill rod on a clamping device of the drilling machine;

s2: starting the drilling machine to drive the spiral drill rod, the end drill rod and the rotary cutting drill bit to cut and drill the coal body;

s3: when the rotary cutting bit is pushed for 1m, the underground air compressor is started to enable high-pressure air to enter the spiral drill rod through the high-pressure rubber pipe and the water braid, and the impact assembly is pushed to impact the coal body in front of the drilling hole, so that a secondary crack is formed; in the process, the high-pressure gas flows out of the drill rod at the end part of the oil, and residual coal dust in the rotary cutting drill bit is discharged;

s4: after drilling to a certain distance, closing the drilling machine, adding a new spiral drill rod, and repeating S2-S4 until the drilling is performed to a preset drilling depth;

s5: and after the drilling construction is finished, plugging the drilling, connecting the gas extraction drilling with a downhole gas extraction pipeline, and carrying out reinforced gas extraction on the coal body of the stope face.

Further, the impact assembly is arranged in the end drill rod in a sliding manner and comprises a rear cavity, a connecting cavity and a front cavity which are sequentially connected, one end of the rear cavity is provided with an arc seat, a fracturing block is arranged in the connecting cavity, and the fracturing block is connected to the bottom of the rear cavity through an impact spring; a fracturing rod is arranged in the front cavity and is connected with the other end of the fracturing block through a reset spring; the other end of the fracturing rod is connected with a spiral impact drill bit.

Further, the step S3 specifically includes: when the rotary cutting drill bit is pushed for 1m, starting an underground air compressor to enable high-pressure air to enter the spiral drill rod through a high-pressure rubber pipe through a water braid, applying pressure to an arc seat on a rear cavity by the high-pressure air, driving the rear cavity, a connecting cavity, a front cavity, an impact spring in the rear cavity and a fracturing block to integrally move towards the bottom of a drilling hole, enabling the fracturing block to impact the fracturing rod, and enabling the spiral impact drill bit to impact a coal body in front of the drilling hole to form a secondary fracture; in the process, high-pressure gas flows out of the hollow part of the rotary cutting bit through the rear cavity, the connecting cavity, the front cavity and the hole between the inner wall of the end drill rod, and slag is discharged from the residual part of coal dust in the rotary cutting bit.

Further, in the fracturing block, an inner hole is formed in one end, in contact with the fracturing rod, of the fracturing block, and the diameter of one end, in contact with the fracturing rod, of the fracturing block is smaller than that of the inner hole of the fracturing block.

Further, one end of the spiral impact drill bit is provided with a drill bit with a spiral, the other end of the spiral impact drill bit is a conical bottom, the middle part of the spiral impact drill bit is provided with a bolt hole, and the corresponding position on the end drill rod is also provided with the bolt hole, so that the spiral impact drill bit is fixed in the end drill rod by inserting a bolt.

Further, the outer wall of the connecting cavity is provided with an arc positioning protrusion, the inner wall of the end drill rod is provided with a groove, and the arc positioning protrusion slides in the groove.

The invention has the beneficial effects that:

(1) The invention organically combines the rotary cutting and impact processes of the drill bit, realizes the drilling and impact fracturing and permeability improvement of the coal seam gas extraction drill hole under the condition of no drilling stop, and has very remarkable technical and economic benefits;

(2) According to the drilling construction and coal seam gas extraction method with the cooperation of rotary cutting and impact permeability improvement, high-pressure air can be conveyed into the spiral drill rod through the air compressor, residual coal dust in the rotary cutting drill bit is discharged while impact fracturing operation is driven, and then the coal dust can be gradually conveyed to a drilling hole opening through the spiral arranged on the outer wall of the drill rod, so that continuous drilling operation is facilitated;

(3) The rotary cutting and impact permeability-increasing cooperative drilling construction and coal seam gas extraction method provided by the invention has the functions of drilling and impact fracturing, and a large number of secondary cracks can be generated by the impact of the spiral impact drill bit on the coal body in front of the drilling, so that the gas permeability of the coal body around the drilling is improved, the coal body is crushed, and the implementation of drilling operation is easy.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and other advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the specification.

Drawings

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in the following preferred detail with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of an end drill pipe and impact assembly;

FIG. 2 is a schematic view of the auger stem structure;

FIG. 3 is a schematic diagram of a drilling rig;

FIG. 4 is a schematic illustration of a drilling operation;

FIG. 5 is a schematic view of an impact wherein (a) and (b) are schematic views of a return spring and impact spring in their uncompressed and compressed states, respectively;

reference numerals: the drill rod comprises an end drill rod 1, a rotary cutting drill bit 2, a spiral drill rod 3, a water swivel 4, a clamping device 5, a spiral impact drill bit 6, a front cavity 7, a reset spring 8, a fracturing rod 9, a connecting cavity 10, a fracturing block 11, an impact spring 12, a rear cavity 13, an arc seat 14, an arc positioning protrusion 15, a bolt 16 and a diamond cutting pick 17.

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be noted that the illustrations provided in the following embodiments merely illustrate the basic idea of the present invention by way of illustration, and the following embodiments and features in the embodiments may be combined with each other without conflict.

Wherein the drawings are for illustrative purposes only and are shown in schematic, non-physical, and not intended to limit the invention; for the purpose of better illustrating embodiments of the invention, certain elements of the drawings may be omitted, enlarged or reduced and do not represent the size of the actual product; it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numbers in the drawings of embodiments of the invention correspond to the same or similar components; in the description of the present invention, it should be understood that, if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc., that indicate an azimuth or a positional relationship based on the azimuth or the positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, but not for indicating or suggesting that the referred device or element must have a specific azimuth, be constructed and operated in a specific azimuth, so that the terms describing the positional relationship in the drawings are merely for exemplary illustration and should not be construed as limiting the present invention, and that the specific meaning of the above terms may be understood by those of ordinary skill in the art according to the specific circumstances.

As shown in fig. 1-5, the rotary cutting and impact permeability-increasing combined drilling construction and coal seam gas extraction method is realized by the following devices, including an end drill rod 1, a rotary cutting drill bit 2, an impact assembly, a spiral drill rod 3, a water braid 4, a drilling machine, a high-pressure rubber pipe and a coal mine underground air compressor.

Wherein the impact assembly comprises: the spiral impact drill bit 6, the front cavity 7, the return spring 8, the fracturing rod 9, the connecting cavity 10, the fracturing block 11, the impact spring 12 and the rear cavity 13 with the circular arc seat 14.

The spiral impact drill bit 6 is provided with a spiral drill bit at one end and a conical bottom at the other end, and the middle part is provided with a bolt hole for being in butt joint with the bolt hole on the end drill rod, so that the position of the spiral impact drill bit 6 can be fixed by inserting the bolt 16. The diameter of the bolt 16 is slightly smaller than the inner diameter of the bolt hole, a certain space allowance is provided, and the sharp point edge of the spiral impact bit 6 is ensured to be slightly higher than the edge of the diamond pick 17 of the rotary cutting bit 2.

The spiral impact drill bit 6 is assembled in the front cavity 7, a flat-bottomed fracturing rod 9 is further installed in the front cavity 7, and the fracturing rod 9 is connected with a fracturing block 11 through a reset spring 8.

One end of the front cavity 7 is provided with threads which can be in threaded connection with one end of the connecting cavity 10; the outer wall of the connecting cavity 10 is provided with an arc positioning protrusion 15, and the arc positioning protrusion 15 can move in a groove arranged on the inner wall of the end drill rod 1.

The method comprises the following steps:

s1: setting up a drilling machine at the position of a coal seam gas extraction drilling hole to be constructed in a transportation cis-slot of a coal mine underground stoping working face, assembling an end drill rod 1 with an impact assembly, arranging a rotary cutting drill bit 2 at one end of the end drill rod 1, and connecting the other end of the end drill rod with a spiral drill rod 3; the other end of the spiral drill rod 3 is connected with the water braid 4 through threads, and the clamping device 5 of the drilling machine is used for fixing the spiral drill rod 3; the other end of the water braid 4 is connected with a high-pressure rubber tube; the high-pressure rubber tube is connected with the air outlet end of the underground coal mine air compressor;

s2: then, starting the drilling machine to drive the spiral drill rod 3, the end drill rod 1 and the rotary cutting drill bit 2 to cut and drill the coal body;

s3: when the rotary cutting bit 2 is pushed for 1m, the underground air compressor is started to enable high-pressure air to enter the inside of the spiral drill rod 3 through the high-pressure rubber pipe and the water braid; then, the high-pressure air applies certain pressure to the arc seat 14 on the rear cavity 13, so as to drive the impact spring 12, the fracturing block 11, the rear cavity 13, the connecting cavity 10 and the front cavity 7 to move towards the direction of the bottom of the drilling hole; because the diameter of the right side of the fracturing rod 9 is smaller than that of the inner hole of the fracturing block 11, the fracturing block 11 suddenly enters into the inner hole of the fracturing block 11 in the compression process of the impact spring 12 and the reset spring 8, and the fracturing block 11 impacts the fracturing rod 9 at a high speed, so that the spiral impact drill bit 6 impacts the coal body in front of a drilling hole, and a secondary fracture is formed; in the process, high-pressure gas flows out of the hollow part of the rotary cutting bit 2 through the holes among the rear cavity 13, the connecting cavity 10, the front cavity 7 and the inner wall of the end drill rod 1, and meanwhile, residual part of coal dust in the rotary cutting bit 2 is discharged;

s4: after drilling to a certain distance, closing the drilling machine, adding a new spiral drill rod 3, and repeating S2-S4 until drilling to a preset drilling depth after connecting;

s5: and plugging the drilling hole after the drilling construction is completed, connecting the gas extraction drilling hole with a downhole gas extraction pipeline, and carrying out reinforced gas extraction on the coal body of the stope face.

Finally, it is noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present invention, which is intended to be covered by the claims of the present invention.

Claims

1. A drilling construction and coal seam gas extraction method combining rotary cutting and impact permeability improvement is characterized in that: the method comprises the following steps:

2. The rotary cutting and impact permeability-increasing combined drilling construction and coal seam gas extraction method according to claim 1, wherein the method is characterized by comprising the following steps of: the impact assembly is arranged in the end drill rod in a sliding manner and comprises a rear cavity, a connecting cavity and a front cavity which are sequentially connected, one end of the rear cavity is provided with an arc seat, a fracturing block is arranged in the connecting cavity, and the fracturing block is connected to the bottom of the rear cavity through an impact spring; a fracturing rod is arranged in the front cavity and is connected with the other end of the fracturing block through a reset spring; the other end of the fracturing rod is connected with a spiral impact drill bit.

3. The rotary cutting and impact permeability-increasing combined drilling construction and coal seam gas extraction method according to claim 2, wherein the method is characterized by comprising the following steps of: the step S3 specifically comprises the following steps: when the rotary cutting drill bit is pushed for 1m, starting an underground air compressor to enable high-pressure air to enter the spiral drill rod through a high-pressure rubber pipe through a water braid, applying pressure to an arc seat on a rear cavity by the high-pressure air, driving the rear cavity, a connecting cavity, a front cavity, an impact spring in the rear cavity and a fracturing block to integrally move towards the bottom of a drilling hole, enabling the fracturing block to impact the fracturing rod, and enabling the spiral impact drill bit to impact a coal body in front of the drilling hole to form a secondary fracture; in the process, high-pressure gas flows out of the hollow part of the rotary cutting bit through the rear cavity, the connecting cavity, the front cavity and the hole between the inner wall of the end drill rod, and slag is discharged from the residual part of coal dust in the rotary cutting bit.

4. The rotary cutting and impact permeability-increasing combined drilling construction and coal seam gas extraction method according to claim 2, wherein the method is characterized by comprising the following steps of: and an inner hole is formed in one end, which is in contact with the fracturing rod, of the fracturing block, and the diameter of one end, which is in contact with the fracturing block, of the fracturing rod is smaller than that of the inner hole of the fracturing block.

5. The rotary cutting and impact permeability-increasing combined drilling construction and coal seam gas extraction method according to claim 2, wherein the method is characterized by comprising the following steps of: the spiral impact drill bit one end is provided with the drill bit that has the spiral, and the other end is the conical bottom, and the mid portion is provided with the bolt hole, the corresponding position on the tip drilling rod also is equipped with the bolt hole, and then makes spiral impact drill bit fix in the tip drilling rod through inserting the bolt.

6. The rotary cutting and impact permeability-increasing combined drilling construction and coal seam gas extraction method according to claim 2, wherein the method is characterized by comprising the following steps of: the outer wall of the connecting cavity is provided with an arc positioning protrusion, the inner wall of the end drill rod is provided with a groove, and the arc positioning protrusion slides in the groove.