Drilling construction and coal seam gas extraction method using coordinated rotary cutting and impact permeability enhancement

Abstract

The present invention relates to a drilling construction and coal seam gas extraction method that cooperates with rotary cutting and impact permeability enhancement, and belongs to the field of coal mine safety technology. A drilling rig is used to drive a spiral drill rod and then drive the drill bit at the end to perform conventional cutting on the coal body. An impact assembly is provided in the end drill rod, which can push the arc seat through the high-pressure air delivered by the air compressor underground, and then drive the fracture block to hit the spiral impact drill bit, and make the spiral impact drill bit hit the coal body in front, so that many cracks are generated in the coal body, thereby improving the permeability characteristics of the coal seam and destroying the structural integrity of the coal body to facilitate the subsequent drilling process. After the drilling construction is completed, the borehole can be sealed and connected to the underground gas extraction pipeline to implement coal seam gas enhanced extraction. The present invention has a simple structure, involves less equipment, has extremely obvious technical and economic benefits, and can provide solid technical support for the efficient management of gas disasters in coal mines.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mine safety, and relates to a drilling construction and coal seam gas extraction method that cooperates with rotary cutting and impact permeability enhancement. Background Art

[0002] Coal mine gas (also known as "coalbed methane") is a combustible gas primarily composed of methane. It occurs primarily in adsorbed and free forms within the pore and fracture systems of coal. It poses a major threat to coal mine safety and is also an unconventional natural gas. Strengthening coal mine gas extraction and the development and utilization of coalbed methane in coal mining areas is of great significance for reducing the greenhouse effect, ensuring coal mine safety, and increasing the supply of clean energy. However, my country's coalbed methane geology is complex, with most seams characterized by high gas content and coal and gas outbursts. The coal bodies also have low permeability, making conventional measures difficult to achieve effective gas control. Therefore, coal mine safety professionals often implement coal seam permeability enhancement techniques, such as hydraulic fracturing, high-pressure hydraulic fracturing, and carbon dioxide phase change fracturing, after drilling holes for coalbed methane extraction. This aims to improve coal gas permeability and enhance gas extraction effectiveness. However, conventional permeability enhancement measures require the addition of specialized equipment after drilling is complete, and the operation is time-consuming, resulting in limited technical and economic benefits. Seeking a synergistic permeability enhancement process during the drilling construction process so that gas extraction drilling construction and permeability enhancement measures complement each other and thus improve the efficiency of mine gas disaster management is one of the key technical problems that coal mine safety science and technology workers urgently need to solve. Summary of the Invention

[0003] In view of this, the object of the present invention is to provide a drilling construction and coal seam gas extraction method that cooperates with rotary cutting and impact permeability enhancement and can solve the above-mentioned problems.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A drilling construction and coal seam gas extraction method using rotary cutting and impact anti-permeability coordination comprises the following steps:

[0006] S1: Install an impact assembly in the end drill rod, install a rotary cutting drill bit on one end of the end drill rod, connect the other end to the auger rod, connect the other end of the auger rod to the water braid, and connect the other end of the water braid to the air outlet of the underground coal mine air compressor through a high-pressure hose; set up the drilling rig at the location where the coal seam gas extraction drilling hole is to be constructed in the transportation chute of the underground coal mine working face, and fix the auger rod to the clamping device of the drilling rig;

[0007] S2: Start the drilling rig to drive the spiral drill rod, end drill rod and rotary cutting drill bit to perform cutting and drilling operations on the coal body;

[0008] S3: When the rotary cutting drill bit advances 1 meter, the downhole air compressor is turned on to allow high-pressure air to enter the spiral drill pipe through the high-pressure hose and the water braid, pushing the impact assembly to impact the coal body in front of the drill hole, thereby forming secondary fractures. During this process, high-pressure gas flows out of the drill pipe at the end of the oil oil to remove some coal dust remaining in the rotary cutting drill bit;

[0009] S4: After drilling to a certain distance, shut down the drilling rig and add a new auger rod, repeating S2 to S4 until the drilling reaches the predetermined drilling depth;

[0010] S5: After the drilling is completed, it will be sealed, and then the gas extraction borehole will be connected to the underground gas extraction pipeline to implement enhanced gas extraction on the coal body of the mining working face.

[0011] Furthermore, the impact assembly is slidably arranged in the end drill rod, including a rear chamber, a connecting chamber and a front chamber connected in sequence, one end of the rear chamber is provided with an arc seat, the connecting chamber is provided with a fracturing block, which is connected to the bottom of the rear chamber through an impact spring; the front chamber is provided with a fracturing rod, which is connected to the other end of the fracturing block through a reset spring; the other end of the fracturing rod is connected to a spiral impact drill bit.

[0012] Furthermore, step S3 specifically includes: when the rotary cutting drill bit advances 1m, the downhole air compressor is turned on to allow high-pressure air to enter the interior of the spiral drill rod through the high-pressure hose and the water braid, and the high-pressure air applies pressure to the arc seat on the rear cavity, driving the rear cavity, the connecting cavity, the front cavity and the impact spring and the fracturing block therein to move toward the bottom of the borehole as a whole, and causing the fracturing block to impact the fracturing rod, so that the spiral impact drill bit impacts the coal body in front of the borehole to form secondary cracks; in this process, the high-pressure gas flows out from the hollow part of the rotary cutting drill bit through the gaps between the rear cavity, the connecting cavity, the front cavity and the inner wall of the end drill rod, and discharges the remaining coal dust in the rotary cutting drill bit.

[0013] Furthermore, in the fracturing block, an end in contact with the fracturing rod is provided with an inner hole, and a diameter of the end in contact with the fracturing rod is smaller than a diameter of the inner hole of the fracturing block.

[0014] Furthermore, a spiral impact drill bit is provided with a drill bit with a spiral at one end, a conical bottom at the other end, and a pin hole is provided in the middle part. A pin hole is also provided at the corresponding position on the end drill rod, and the spiral impact drill bit is fixed in the end drill rod by inserting the pin.

[0015] Furthermore, an arc positioning protrusion is provided on the outer wall of the connecting cavity, and a groove is provided on the inner wall of the end drill rod, and the arc positioning protrusion slides in the groove.

[0016] The beneficial effects of the present invention are:

[0017] (1) The present invention organically combines the rotary cutting and impact processes of the drill bit to achieve the drilling and impact fracturing and permeability enhancement of coal seam gas extraction boreholes without stopping drilling, which has extremely significant technical and economic benefits;

[0018] (2) The rotary cutting and impact permeability enhancement coordinated drilling construction and coal seam gas extraction method provided by the present invention can deliver high-pressure air to the interior of the spiral drill rod through an air compressor, while driving the impact fracturing operation, to discharge the residual coal dust in the rotary cutting drill bit. The coal dust can then be gradually transported to the borehole orifice through the spiral provided on the outer wall of the drill rod, which is extremely beneficial to the continuous progress of the drilling operation;

[0019] (3) The present invention provides a drilling construction and coal seam gas extraction method that combines rotary cutting with impact permeability enhancement. It has the functions of both drilling and impact fracturing. The spiral impact drill bit impacts the coal body in front of the borehole, which can generate a large number of secondary cracks, thereby improving the gas permeability characteristics of the coal body around the borehole and breaking the coal body, making it easier to implement drilling operations.

[0020] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0022] Figure 1 It is a schematic diagram of the end drill rod and impact assembly structure;

[0023] Figure 2 This is a schematic diagram of the spiral drill rod structure;

[0024] Figure 3 This is a schematic diagram of the drilling rig;

[0025] Figure 4 This is a schematic diagram of drilling construction operations;

[0026] Figure 5 Schematic diagram of impact, where (a) and (b) are schematic diagrams of the return spring and impact spring in the uncompressed and compressed states, respectively;

[0027] Figure numerals: end drill rod 1, rotary cutting drill bit 2, spiral drill rod 3, water braid 4, clamping device 5, spiral impact drill bit 6, front chamber 7, return spring 8, fracturing rod 9, connecting chamber 10, fracturing block 11, impact spring 12, rear chamber 13, arc seat 14, arc positioning protrusion 15, pin 16, diamond pick 17. DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0029] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0030] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0031] like Figure 1-5 As shown, the rotary cutting and impact permeability enhancement coordinated drilling construction and coal seam gas extraction method of the present invention is realized by the following devices, including an end drill rod 1, a rotary cutting drill bit 2, an impact assembly, an auger rod 3, a water braid 4, a drilling rig, a high-pressure hose and an underground coal mine air compressor.

[0032] The impact assembly includes: a spiral impact drill bit 6, a front chamber 7, a return spring 8, a fracturing rod 9, a connecting chamber 10, a fracturing block 11, an impact spring 12, and a rear chamber 13 with a circular arc seat 14.

[0033] The spiral percussion drill bit 6 has a spiral drill bit at one end and a conical bottom at the other end. A pin hole is provided in the middle for docking with the pin hole on the end drill rod. The position of the spiral percussion drill bit 6 can then be fixed by inserting a pin 16. The diameter of the pin 16 is slightly smaller than the inner diameter of the pin hole, leaving a certain amount of space margin, and ensuring that the sharp edge of the spiral percussion drill bit 6 is slightly higher than the edge of the diamond pick 17 of the rotary cutting drill bit 2.

[0034] The spiral impact drill bit 6 is assembled in the front chamber 7. A flat-bottomed fracturing rod 9 is also installed in the front chamber 7. The fracturing rod 9 is connected to the fracturing block 11 through a return spring 8.

[0035] One end of the front chamber 7 is provided with a thread, which can be threadedly connected to one end of the connecting chamber 10; the outer wall of the connecting chamber 10 is provided with an arc positioning protrusion 15, which can move in a groove provided on the inner wall of the end drill rod 1.

[0036] This method comprises the following steps:

[0037] S1: At the location where the coal seam gas extraction drilling hole is to be constructed in the transport chute of the coal mining face, a drilling rig is set up and the end drill rod 1 and the impact assembly are assembled. Then, a rotary cutting drill bit 2 is set at one end of the end drill rod 1, and the other end is connected to the auger rod 3. The other end of the auger rod 3 is connected to the water braid 4 through a thread, and the auger rod 3 is fixed by the clamping device 5 of the drilling rig. The other end of the water braid 4 is connected to a high-pressure hose. The high-pressure hose is connected to the air outlet of the air compressor in the coal mine.

[0038] S2: The drilling rig is then turned on to drive the spiral drill rod 3, the end drill rod 1, and the rotary cutting drill bit 2 to perform cutting and drilling operations on the coal body;

[0039] S3: When the rotary cutting drill bit 2 advances 1m, the downhole air compressor is turned on to allow high-pressure air to enter the interior of the spiral drill rod 3 through the high-pressure hose and the water braid; then the high-pressure air will apply a certain pressure to the arc seat 14 on the rear chamber 13, thereby driving the impact spring 12, the fracturing block 11, the rear chamber 13, the connecting chamber 10, and the front chamber 7 to move as a whole toward the bottom of the borehole; since the right side diameter of the fracturing rod 9 is smaller than the diameter of the inner hole of the fracturing block 11, the impact spring 12 and the return spring 8 will suddenly enter the inner hole of the fracturing block 11 during the compression process, causing the fracturing block 11 to impact the fracturing rod 9 at high speed, thereby causing the spiral impact drill bit 6 to impact the coal body in front of the borehole, thereby forming secondary cracks; in this process, the high-pressure gas will flow out from the hollow part of the rotary cutting drill bit 2 through the gaps between the rear chamber 13, the connecting chamber 10, the front chamber 7 and the inner wall of the end drill rod 1, and at the same time, the remaining coal dust in the rotary cutting drill bit 2 will be discharged;

[0040] S4: After drilling to a certain distance, the drilling machine is turned off and a new spiral drill rod 3 is added. After connection, S2 to S4 are repeated until the drilling reaches the predetermined drilling depth;

[0041] S5: After the drilling is completed, it will be sealed immediately, and then the gas extraction borehole will be connected to the underground gas extraction pipeline to implement enhanced gas extraction on the coal body of the mining working face.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A drilling construction and coal seam gas extraction method using a combination of rotary cutting and impact permeability enhancement, characterized by: The following steps are involved: S1: Install an impact assembly in the end drill rod, install a rotary cutting drill bit on one end of the end drill rod, connect the other end to the auger rod, connect the other end of the auger rod to the water braid, and connect the other end of the water braid to the air outlet of the underground coal mine air compressor through a high-pressure hose; set up the drilling rig at the location where the coal seam gas extraction drilling hole is to be constructed in the transportation chute of the underground coal mine working face, and fix the auger rod to the clamping device of the drilling rig; S2: Start the drilling rig to drive the spiral drill rod, end drill rod and rotary cutting drill bit to perform cutting and drilling operations on the coal body; S3: When the rotary cutting drill bit advances 1 meter, the downhole air compressor is turned on to allow high-pressure air to enter the spiral drill pipe through the high-pressure hose and the water braid, pushing the impact assembly to impact the coal body in front of the drill hole, thereby forming secondary fractures. During this process, high-pressure gas flows out of the end drill pipe to remove some coal dust remaining in the rotary cutting drill bit; S4: After drilling to a certain distance, shut down the drilling rig and add a new auger rod, repeating S2 to S4 until the drilling reaches the predetermined drilling depth; S5: After the drilling is completed, it will be sealed, and then the gas extraction borehole will be connected to the underground gas extraction pipeline to implement enhanced gas extraction on the coal body of the mining working face.

2. The method for drilling and coal seam gas extraction using coordinated rotary cutting and impact anti-permeability according to claim 1, characterized in that: The impact assembly is slidably arranged in the end drill rod, and includes a rear cavity, a connecting cavity and a front cavity connected in sequence. An arc seat is provided at one end of the rear cavity, and a fracturing block is provided in the connecting cavity, which is connected to the bottom of the rear cavity through an impact spring; a fracturing rod is provided in the front cavity, which is connected to the other end of the fracturing block through a reset spring; and a spiral impact drill bit is connected to the other end of the fracturing rod.

3. The method for drilling and coal seam gas extraction using coordinated rotary cutting and impact anti-permeability according to claim 2, characterized in that: Step S3 specifically includes: when the rotary cutting drill bit advances 1m, turning on the downhole air compressor to allow high-pressure air to enter the interior of the spiral drill rod through the high-pressure hose and the water braid, and the high-pressure air applies pressure to the arc seat on the rear cavity, driving the rear cavity, the connecting cavity, the front cavity and the impact spring and the fracturing block therein to move toward the bottom of the borehole as a whole, and causing the fracturing block to impact the fracturing rod, so that the spiral impact drill bit impacts the coal body in front of the borehole to form secondary cracks; in this process, the high-pressure gas flows out from the hollow part of the rotary cutting drill bit through the gaps between the rear cavity, the connecting cavity, the front cavity and the inner wall of the end drill rod, and discharges the remaining coal dust in the rotary cutting drill bit.

4. The method for drilling and coal seam gas extraction using coordinated rotary cutting and impact anti-permeability according to claim 2, characterized in that: In the fracturing block, an end in contact with the fracturing rod is provided with an inner hole, and a diameter of the end in contact with the fracturing rod is smaller than a diameter of the inner hole of the fracturing block.

5. The method for drilling and coal seam gas extraction using coordinated rotary cutting and impact anti-permeability according to claim 2, characterized in that: One end of the spiral impact drill bit is provided with a drill bit with a spiral, the other end is a conical bottom, and a pin hole is provided in the middle part. The corresponding position on the end drill rod is also provided with a pin hole, and the spiral impact drill bit is fixed in the end drill rod by inserting the pin.

6. The method for drilling and coal seam gas extraction using coordinated rotary cutting and impact anti-permeability according to claim 2, characterized in that: The outer wall of the connecting cavity is provided with an arc positioning protrusion, and the inner wall of the end drill rod is provided with a groove, and the arc positioning protrusion slides in the groove.

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