CN115012850B - Double power shield pressure relief spiral slag removal combined drilling tool for outburst coal seam - Google Patents

Abstract

The invention discloses a double-power shield pressure relief spiral deslagging combined drilling tool for an outstanding coal seam, which comprises a shield pressure relief reaming drilling tool, a spiral blade drilling tool and a sliding guide sleeve, wherein the shield pressure relief reaming drilling tool consists of a sieve pore drill rod and a hollow reaming drill bit; during drilling, the spiral blade drilling tool performs spiral deslagging drilling at the bottom of the hole, and the shield pressure relief reaming drilling tool performs shield pressure relief reaming drilling immediately after the spiral blade drilling tool performs the spiral deslagging drilling; the combined drilling tool is matched with a double-power-head drilling machine for use, is used for the construction of gas extraction drilling holes which are difficult to form holes, such as soft outburst coal seams, high-stress coal seams and the like, and has good drilling operation environment due to the fact that spiral machinery is adopted for deslagging.

Description

Double power shield pressure relief spiral slag removal combined drilling tool for outburst coal seam

Technical Field

The present invention relates to the technical field of coal mine gas extraction drilling, mainly for the construction of gas extraction in deep protruding coal seams, soft coal seams and coal seams that are difficult to drill holes, and in particular to a double-power shield pressure relief spiral slag removal combined drilling tool for protruding coal seams.

Background Art

The drill rods used in the current gas extraction drilling construction of deep protruding coal seams, soft-hard composite coal seams, and broken soft coal seams are mostly grooved drill rods, ribbed drill rods, triangular grooved drill rods, triangular drill rods and other special-shaped drill rods. Among them, the patent applicants for the first three types of drill rods are the applicant, Henan Polytechnic University, and the patent numbers are ZL200610111830.7, ZL200920088879.4, and ZL200910064973.0 respectively. The common feature of these special-shaped drill rods is the use of fluid slag removal, and the annular space between the outer surface of the drill rod and the borehole wall is the slag removal channel. Since the slag removal channel is outside the outer surface of the drill rod, it is called an external slag removal channel.

Deep coal seams have high ground stress, high gas content, and high gas pressure. Dynamic phenomena such as coal hole collapse, coal drilling, and coal and gas outburst in the hole can all lead to collapse and blockage of the external slag discharge channel. The difficulty in slag discharge is the fundamental reason for the difficulty in drilling in protruding coal seams. When using an external slag discharge channel, since the external slag discharge channel requires a spatial scale, the drill rod diameter must be smaller than the drill bit diameter, the disturbance space of the drill rod in the coal hole is large, and the straightening device lacks a stable support foundation in the coal hole and cannot be used normally, resulting in serious deviation of the coal seam drilling, and the drilling trajectory encounters the coal seam roof or coal seam floor too early. The deviation of the drilling hole not only affects the drilling depth, but also causes the drill rod to be subjected to alternating stress, increasing the probability of broken drill. Although the current screw motor directional drilling technology can solve the problem of coal hole deviation, the drilling depth in the protruding coal seam is limited, and the cost of drilling and losing the drill is too high. It is not suitable for use in protruding coal seams. Therefore, the screw motor directional drilling technology has not been promoted and applied in protruding coal seams.

Double-tube drilling technology was used for drilling in shallow loose rock and soil layers in the last century. Double-tube internal circulation and outer-tube drill tools were used to protect the borehole from scouring damage and hole wall collapse. After the hole was formed, the inner-tube drill tool was first withdrawn, and then the buried wire pipe, pipeline, etc. were inserted into the hole through the outer-tube drill tool, and finally the outer-tube drill tool was pulled out of the hole. Since the ground stress of shallow rock and soil is very small, the lifting and withdrawal of the outer-tube drill tool is easy to achieve. Therefore, double-tube drill tools are widely used in ground or shallow tunnel projects. If traditional double-tube drilling is used for protruding coal seams, due to factors such as high ground stress and soft coal seams, it is highly likely that the outer tube (external tube drill tool) will be crushed to death. In 2005, the Hebi mining area of Henan Energy and Chemical Group used double-tube drill tools made in Japan to conduct drilling tests in the protruding coal seams in the Hebi mining area. The test showed that the outer tube was easily crushed and blocked, and the test was unsuccessful.

In order to solve the problem of drilling in protruding coal seams, the applicant has successively applied for a series of shield-protected pressure-relieving drill rods, such as: a circumferential flow-supplying, hole-protecting and pressure-relieving sieve-hole drill rod for protruding coal seams (ZL 202110726041.9), a hole-protecting and pressure-relieving internal slag-discharging drill rod (ZL201810488034.8), a hole-protecting and pressure-relieving combined drilling tool for protruding coal seams and its use method (ZL 202010648997.7), a shield-protected and pressure-relieving sieve-hole arc-edge drill rod for corner flow supply in protruding coal seams (ZL 202111152968.2), etc. The drill rod of the above-mentioned disclosed invention is a double-layer structure. The basic idea is: utilizing the double-layer structure of the drill rod, the rod body itself includes an internal slag discharge channel, a flow supply channel and a radial slag discharge screen hole, and the unreliable external slag discharge channel is replaced by a reliable internal slag discharge channel. Therefore, the outer diameter of the drill rod can be equal to or slightly smaller than the diameter of the drill bit, so that the drill rod has a shielding effect and a straightening effect on the drill hole, and the slag discharge screen hole has a pressure relief effect on the drill rod to prevent the drill rod from being crushed to death.

The above-mentioned drilling tools all need to use wind or water flow as the power for slag removal, which belongs to the category of fluid slag removal drilling tools. The drilling operation site of fluid slag removal drilling tools often has harsh environments such as water flow, wind flow, water coal slag, and dust, and the working environment is extremely poor. In the case of hydraulic slag removal, it is necessary to equip water coal slag separation equipment, filter press equipment, sewage pump, sedimentation box (tank), anti-spray hole drainage device, etc. In the case of wind slag removal, it is necessary to equip dust removal device, negative pressure water jet dust removal device, dustproof water curtain, anti-spray hole drainage device. Since water is used for dust removal, there is also the problem of water treatment.

Traditional spiral blade drill tools do not require fluid slag removal power, so the drilling environment is good and there is no problem of water coal slag treatment. Because there is little dust, dust removal devices are generally not required. Because spiral blade drill tools themselves have certain anti-blowout hole functions, they generally do not need to be equipped with anti-blowout hole devices. However, since the drill holes in the protruding coal seams are very easy to collapse, and the coal cannon and other dynamic phenomena are frequent, the spiral blade drill tools are very prone to drill suction and drill jamming during the drilling of the protruding coal seams. Drill suction and drill jamming result in a very shallow drilling depth and poor use effect. Around 2008, when special-shaped drill rods such as grooved drill rods, rib drill rods, triangular grooved drill rods and triangular drill rods were invented, in the field of drilling in protruding coal seams, these special-shaped drill rods that use fluid as slag removal power not only replaced the traditional spiral blade drill rods with mechanical slag removal, but also replaced the traditional round-face drill rods with fluid slag removal.

In order to give full play to the advantages of spiral blade drilling tools and overcome the inadaptability of spiral blade drilling tools, the present invention proposes: a dual-power shield pressure relief spiral slag removal combined drilling tool for protruding coal seams. The basic idea is: adopt the current dual-power head drilling rig, use two rotating power heads to drive the shield pressure relief hole expansion drilling tool (external tube drilling tool) and the traditional spiral blade drilling tool (inside tube drilling tool) respectively, and use the shield pressure relief hole expansion drilling tool to protect the traditional spiral blade drilling tool, so that the advantages of shield pressure relief drilling and mechanical spiral drilling are organically combined to form a shield pressure relief spiral slag removal combined drilling tool. The spiral blade drilling tool implements spiral slag removal drilling at the bottom of the hole, and the shield pressure relief hole expansion drilling tool implements hole expansion drilling immediately thereafter, so that the spiral blade drilling tool is prevented from being squeezed by ground pressure and interfered by coal cannons, so that the spiral blade drilling tool no longer has the phenomenon of drilling suction and drilling jamming, and the two drilling tools share an internal slag removal channel for spiral transportation. All the drilling tools previously invented by the inventor are fluid slag removal drilling tools, and the drilling tool invented this time is a spiral mechanical slag removal drilling tool.

Summary of the invention

Aiming at the problems existing in existing coal seam drilling, the present invention discloses a double-power shield pressure relief spiral slag removal combination drill tool for protruding coal seams, which is mainly aimed at the construction of gas extraction drilling holes in deep protruding coal seams, soft coal seams and difficult-to-drill holes, and can also be used for other large-diameter drilling construction.

The technical solutions adopted to achieve the above objectives are:

A double-power shield pressure relief spiral slag removal combined drilling tool for protruding coal seams comprises a shield pressure relief hole expansion drilling tool, a spiral blade drilling tool and a sliding guide sleeve, wherein the shield pressure relief hole expansion drilling tool comprises a plurality of screen hole drill rods (2) and a hollow hole expansion drill bit (1), and the spiral blade drilling tool comprises a plurality of spiral blade drill rods (3) and a common drill bit (4). The sliding guide sleeve (5) is installed in the inner hole of the hollow hole expansion drill bit (1) by using a shear pin (6). During drilling, the spiral blade drilling tool performs spiral slag removal drilling at the bottom of the hole, and the shield pressure relief hole expansion drilling tool performs shield pressure relief hole expansion drilling immediately after the spiral blade drilling tool, and the spiral blade drill rod (3) performs spiral slag removal in the inner cavity of the screen hole drill rod (2); during drilling withdrawal, the spiral blade drilling tool and the sliding guide sleeve (5) first withdraw from the inner cavity of the shield pressure relief hole expansion drilling tool to the outside of the hole, and then the shield pressure relief hole expansion drilling tool withdraws from the borehole to the outside of the hole.

Furthermore, the spiral blade drill tool has no essential difference from the existing spiral blade drill tool. The difference is that most of the spiral blade drill rods (3) of the spiral blade drill tool are located in the inner cavity of the screen hole drill rod (2), and the distance between the ordinary drill bit (4) and the hollow reaming drill bit (1) is maintained at 0 to 1 drill rod length, that is, the forward length of the spiral blade drill rod is 0 to 1 drill rod length, which can avoid the spiral blade drill tool from getting stuck, pressed or sucked, and overcome the disadvantages of using the spiral blade drill tool alone.

Furthermore, the outer diameter of the sieve hole drill rod (2) is equal to or smaller than the outer diameter of the hollow reaming drill bit (1). During the drilling process, the borehole wall undergoes necking deformation, which causes the sieve hole drill rod (2) to contact the borehole wall. The sieve hole drill rod (2) has a shielding effect on the borehole wall, which can prevent the borehole wall from collapsing, similar to the effect of a shield machine.

Furthermore, a reverse spiral groove (21) is provided on the screen hole drill rod (2) of the shield pressure relief expansion drilling tool, a plurality of slag discharge screen holes (22) penetrating the wall thickness of the screen hole drill rod (2) are provided in the spiral groove (21), a spiral cone hole plate (7) is welded in the groove provided with the slag discharge screen hole (22), the minor diameter of the cone hole (71) is smaller than the diameter of the slag discharge screen hole (22), the major diameter of the cone hole (71) is equal to the diameter of the slag discharge screen hole (22), so that the diameter of the slag inlet of the slag discharge screen hole (22) is smaller than the diameter of the slag outlet, thereby improving the slag discharge efficiency of the slag discharge screen hole and making the screen hole less likely to be blocked; the number of cone holes on the spiral cone hole plate (7) is equal to the number of the slag discharge screen holes (22) and is coaxially matched; the thickness of the spiral cone hole plate (7) is smaller than the depth of the spiral groove (21). In order to increase the rubbing and crushing function of the spiral cone hole strip (7) facing the coal surface, methods such as indentation and spraying of wear-resistant particles can be implemented on the spiral cone hole strip (7), and the cone hole can be punched or drilled. Similar related auxiliary technologies are also within the protection scope of the present invention. In specific implementation, the spiral groove (21) can also be designed as an axial groove, and the corresponding slag discharge screen hole (22) is arranged along the axial direction. This change will reduce the cooling function and slag discharge effect of the screen hole drill rod (2), but will improve the processing efficiency of the screen hole, which is also within the protection scope of this patent. In specific implementation, the above-mentioned grooves and slag discharge sieve holes can be eliminated, and relatively large elliptical holes, elongated holes, etc. can be excavated on the surface of the drill rod of the shield pressure relief hole expansion drill tool. The coal slag from the borehole wall enters the inner cavity of the shield pressure relief hole expansion drill tool through the circular holes and elongated holes, and then is discharged out of the hole by the spiral blade drill rod (3). This change is also a feasible solution, which will bring convenience to the slag discharge outside the hole of the shield pressure relief hole expansion drill tool, but will bring difficulty to the strength matching design of the shield pressure relief hole expansion drill tool, and will also increase the slag discharge resistance of the spiral blade drill tool, which is also within the protection scope of the present invention.

Furthermore, the slag discharge screen hole (22) reduces the radial pressure of the borehole wall on the screen hole drill rod (2) by discharging slag, so the shield protection pressure relief reaming drill has its own pressure relief function, which can avoid the situation of the shield protection pressure relief reaming drill being stuck or pressed. Shield protection and pressure relief are a pair of contradictions. The method to solve this contradiction is to adjust the difference δ between the outer radius of the reaming drill bit (1) and the outer radius of the screen hole drill rod (2), optimize and adjust the δ value according to the specific coal seam geological conditions, and obtain a shield protection pressure relief effect that can meet the requirements of drilling body and straightness; in addition, optimizing the parameters such as the groove depth, groove width, number of screen holes, and diameter of the screen hole drill rod (2) will also affect the shield protection pressure relief effect, and the drilling rig rotation speed and propulsion speed will also affect the shield protection pressure relief effect. In actual applications, the relevant parameter matching conclusions or results obtained by using methods such as physical simulation, numerical simulation and field test are also within the scope of invention protection because the principle method has not changed.

Furthermore, a shear pin (6) is used to connect the sliding guide sleeve installed in the inner cavity of the hollow reaming drill bit and the hollow reaming drill bit (1); the sliding guide sleeve (5) enables the hollow reaming drill bit (1) and the spiral blade drill rod (3) to remain coaxial; and the shear pin (6) is a disposable consumable.

Furthermore, the outer diameter of the sliding guide sleeve (5) is equal to the inner diameter of the hollow reaming drill bit (1), the inner diameter of the hollow reaming drill bit (1) is equal to the inner diameter of the screen hole drill rod (2), the inner diameter of the sliding guide sleeve (5) is equal to the outer diameter of the spiral blade drill rod (3), and the outer diameter of the ordinary drill bit (4) is larger than the inner diameter of the sliding guide sleeve (5) and smaller than the outer diameter of the sliding guide sleeve (5). The purpose of all these size matching is that when the spiral blade drill tool is withdrawn from the inner cavity of the shield pressure relief reaming drill tool, the shear pin (6) is sheared off, and the sliding guide sleeve (5) is withdrawn from the hole together with the spiral blade drill tool. After the spiral blade drill tool is withdrawn from the inner cavity of the shield pressure relief reaming drill tool, the hole protection screen can be lowered through the inner cavity of the shield pressure relief reaming drill tool, and then the shield pressure relief reaming drill tool is withdrawn from the hole, while the hole protection screen is left in the borehole. There are many other alternative matching modes for shield pressure relief hole expansion drilling tools and spiral blade drilling tools. The following alternative matching modes are also within the scope of protection of this patent:

Alternative fit 1: If the outer diameter of the common drill bit (4) and the outer diameter of the spiral blade drill rod (3) are designed to be equal, the shear pin (6) can be changed to a fixed pin, and the sliding guide sleeve (5) does not need to be withdrawn from the drilling hole along with the spiral blade drill.

Alternative combination 2: If the outer diameter of the ordinary drill bit (4) and the outer diameter of the spiral blade drill rod (3) are designed to be equal and equal to the inner diameter of the screen hole drill rod (2), the shear pin (6) and the sliding guide sleeve (5) can be eliminated. However, the problem caused by this simplified solution is that the gas generated by drilling is not discharged smoothly. It can be applied to high-stress low-gas coal seams, but not to soft protruding coal seams.

Alternative combination three: If the outer diameter of the ordinary drill bit (4) and the outer diameter of the spiral blade drill rod (3) are designed to be equal and equal to the inner diameter of the screen hole drill rod (2), and an exhaust hole that passes through the thickness of the blade is provided on the blade edge of the spiral blade drill rod, the shear pin (6) and the sliding guide sleeve (5) can be eliminated. Although this solution can solve the problem of gas discharge, it increases the processing cost.

Alternative combination 4: A support ring is embedded in the inner hole of each sieve hole drill rod (2), and the outer diameter of the ordinary drill bit (4) and the outer diameter of the spiral blade drill rod (3) are designed to be equal and equal to the inner diameter of the support ring. Then, the shear pin (6) and the sliding guide sleeve (5) can be eliminated. This solution can avoid contact and collision between the sieve hole drill rod (2) and the spiral blade drill rod (3), but the coal slag inside the sieve hole drill rod (2) is not easy to be discharged, and it also has a certain impact on the discharge of gas, which will also increase the processing cost of the drilling tool.

Furthermore, the spiral blade drill rods (3) are connected by plug-in connection, which is the most commonly used connection method for spiral blade drill rods. The sieve hole drill rods (2) are connected by threaded connection. During operation, the spiral blade drill tool rotates in the forward direction, and the shield pressure relief and hole expansion drill tool rotates in the reverse direction. The spiral blade drill tool and the shield pressure relief and hole expansion drill tool rotate in opposite directions, so that the relative rotation speed of the spiral blade drill rod (3) and the sieve hole drill rod (2) can be higher, thereby improving the slag removal efficiency of the spiral mechanical slag removal. In specific implementation, the spiral blade drill rods (3) can be plug-in connected or threaded connected. When threaded connected, a proper amount of compressed air can be supplied to the central hole of the spiral blade drill rod (3) to improve the deslagging efficiency of the spiral blade drill. In downward-inclined drilling construction, this auxiliary measure can be added, which is also within the protection scope of the present invention. If a rock layer such as mudstone with strong viscosity is encountered, a proper amount of static pressure water can be supplied to the central hole of the spiral blade drill rod (3) to prevent the mudstone from adhering to the spiral blade and affecting the spiral deslagging effect, which is also within the protection scope of the present invention.

The beneficial effects of the present invention are:

(1) The present invention organically combines a shield pressure relief hole expansion drill tool with a traditional spiral blade drill tool to form a shield pressure relief spiral slag removal combined drill tool. The shield pressure relief characteristic of the shield pressure relief hole expansion drilling is utilized, and the borehole is protected on the outside and the spiral blades are protected on the inside, thereby overcoming the disadvantages of the spiral blade drill tool such as drill suction and drill sticking, and the depth, straightness and hole quality of the protruding coal seam gas extraction borehole can be improved.

(2) The shield-protected pressure-relief spiral slag removal combined drill tool of the present invention replaces the widely used fluid slag removal with spiral mechanical slag removal, thereby eliminating the auxiliary treatment equipment such as water coal slag and dust required for fluid slag removal. No water or wind power is required during drilling, and there is no dust or water coal slag at the drilling site, providing a good working environment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the shield pressure relief spiral slag removal combined drilling tool of the present invention;

FIG2 is a schematic diagram of the shield pressure relief hole expansion drilling tool of the present invention;

FIG3 is a diagram showing the coordination of the spiral groove, the slag discharge screen hole and the tapered hole strips of the present invention;

FIG4 is a schematic diagram of the spiral tapered hole strip of the present invention;

FIG. 5 is a schematic diagram of the spiral blade drilling tool of the present invention.

DETAILED DESCRIPTION

The present invention is further described below in conjunction with the accompanying drawings.

Fig. 1 is a scheme diagram of the shield pressure relief spiral slag removal combined drilling tool of the present invention. The dual-power shield pressure relief spiral slag removal combined drilling tool for protruding coal seams includes a shield pressure relief hole expansion drilling tool, a spiral blade drilling tool and a sliding guide sleeve 5 that are matched with each other through a sleeve. The shield pressure relief hole expansion drilling tool includes a hollow hole expansion drill bit 1 and a plurality of sieve hole drill rods 2 connected together. The spiral blade drilling tool includes a common drill bit 4 and a plurality of spiral blade drill rods 3. The spiral blade drilling tool passes through the inner cavity of the shield pressure relief drilling tool. The sliding guide sleeve 5 is installed in the inner hole of the hollow hole expansion drill bit 1 by using a shear pin 6. The sliding guide sleeve 5 keeps the hollow hole expansion drill bit 1 coaxial with the spiral blade drill rod 3. The shield pressure relief drilling tool, the spiral blade drilling tool and the sliding guide sleeve 5 together constitute a combined drilling tool.

During drilling, the spiral blade drill implements spiral slag removal drilling at the bottom of the hole, the shield pressure relief reaming drill implements shield pressure relief reaming drilling immediately after the spiral blade drill, and the spiral blade drill rod 3 implements spiral slag removal in the inner cavity of the screen hole drill rod 3. In specific implementation, the effective length of the screen hole drill rod 2 is the same as the effective length of the spiral blade drill rod 3, and the distance between the ordinary drill bit 4 and the hollow reaming drill bit 1 is maintained at the length of 0 to 1 drill rod, that is, the extended length of the spiral blade drill rod is 0 to 1 drill rod length, which can avoid the situation of the spiral blade drill tool being stuck, pressed or sucked, and overcome the disadvantages of the spiral blade drill tool when used alone. In specific implementation, the first spiral blade drill rod 3 connected to the ordinary drill bit 4 can also be 200mm to 300mm longer than the ordinary drill rod, and the borehole drilled by the spiral blade drill tool is protected by the shield pressure relief reaming drill in time, which has a principle similar to that of a shield machine.

When withdrawing the drill, the shear pin 6 is sheared off by the withdrawing drill force, and the spiral blade drill tool together with the sliding guide sleeve 5 first withdraws from the hole through the inner cavity of the shield pressure relief and hole expansion drill tool, and then the shield pressure relief and hole expansion drill tool withdraws from the borehole. Before the shield pressure relief and hole expansion drill tool is withdrawn, the inner cavity of the shield pressure relief and hole expansion drill tool can be used to lower the hole protection screen hole.

Fig. 2 is a schematic diagram of the shield protection pressure relief reaming drill tool of the present invention. A sliding guide sleeve 5 is installed in the inner hole of the hollow reaming drill bit 1 through a shear pin 6. The shear pin 6 is made of soft metal and is made of easy-to-shear material. The inner diameter of the shear pin 6 is equal to the outer diameter of the spiral blade drill rod 3, the outer diameter of the shear pin 6 is equal to the inner diameter of the hollow reaming drill bit 1, and the outer diameter of the shear pin 6 is equal to or slightly smaller than the inner diameter of the sieve hole drill rod 2. In specific implementation, the outer diameter of the sieve hole drill rod 2 is equal to or smaller than the outer diameter of the hollow reaming drill bit 1, and the diameter difference is 0 to 15 mm. During the drilling process, the borehole is necked and deformed, which will cause the sieve hole drill rod 2 to contact the borehole wall. The sieve hole drill rod 2 has a shielding effect on the borehole wall, which can prevent the collapse of the borehole wall. The outer surface of the sieve hole drill rod 2 is provided with a reverse spiral groove 21, and a slag discharge screen hole 22 penetrating the wall thickness of the sieve hole drill rod 2 is provided in the spiral groove 21. The coal slag generated by the deformation and collapse of the drilling hole enters the inner cavity of the sieve hole drill rod 2 through the slag discharge screen hole 22. The slag discharge screen hole 22 has a pressure relief effect on the sieve hole drill rod 2, which can prevent the sieve hole drill rod 2 from being crushed to death. During implementation, the shield pressure relief expansion drill tool and the spiral blade drill tool have opposite rotation directions, which can improve the spiral slag discharge efficiency of the spiral blade drill rod 3 in the sieve hole drill rod 2 and prevent the drill tool from being disengaged. Therefore, the spiral groove 21 is a reverse spiral, and the thread of the shield pressure relief drill tool adopts a reverse thread.

FIG3 is a diagram of the coordination of the spiral groove, the slag discharge screen hole and the spiral cone hole strip of the present invention. The test shows that the slag discharge effect of the inverted cone slag discharge screen hole is better than that of the straight hole, but the inverted cone slag discharge screen hole is difficult to process, the processing cost is high, and the processing efficiency is low. In order to improve the slag discharge effect of the slag discharge screen hole 22, a spiral cone hole strip 7 as shown in FIG4 is welded in the spiral groove 21. A plurality of cone holes 71 are arranged on the spiral cone hole strip 7. The small diameter of the cone hole 71 is smaller than the diameter of the slag discharge screen hole 22, and the large diameter of the cone hole 71 is equal to the diameter of the slag discharge screen hole 22, so that the diameter of the slag inlet of the slag discharge screen hole 22 is smaller than the diameter of the slag outlet. This can improve the slag discharge efficiency of the slag discharge screen hole 22 and make the screen hole less likely to be blocked. The number of cone holes 71 on the spiral cone hole strip 7 is equal to the number of the slag discharge screen hole 22 and is coaxially matched; the thickness of the spiral cone hole strip 7 is less than the depth of the spiral groove 21. In specific implementation, for extremely soft protruding coal seams, the coal slag from the borehole wall will be very fine, and the spiral cone hole slats 7 can be eliminated. Therefore, the solution of eliminating the spiral cone hole slats 7 is also within the protection scope of the present invention. However, for deep well high-stress medium-hard protruding coal seams, the coal slag from the borehole wall will be very hard. If straight holes are used for the slag discharge screen holes, the screen holes will be easily blocked, which is not conducive to the slag discharge and pressure relief of the shield pressure relief drill bit.

FIG5 is a schematic diagram of the spiral blade drill tool of the present invention. There is no essential difference between the spiral blade drill tool of the present invention and the existing spiral blade drill tool. The ordinary drill bit 4 is a multi-type drill bit matched with the spiral blade drill rod. The outer diameter of the ordinary drill bit 4 is larger than the inner diameter of the sliding guide sleeve 5, and the outer diameter of the ordinary drill bit 4 is smaller than the outer diameter of the sliding guide sleeve 5. When the spiral blade drill tool is withdrawn, the drilling force cuts off the shear pin 6, and the sliding guide sleeve 5 withdraws from the inner cavity of the shield pressure relief drill tool together with the spiral blade drill tool. The sliding guide sleeve 5 has multiple functions. One is to allow the two drill tools to drill coaxially. The second is to allow a gap between the spiral blade drill rod 3 and the screen hole drill rod 2. This gap is conducive to the discharge of gas. The third is to prevent the spiral blade drill tool from scratching the shield pressure relief drill tool during the withdrawal process.

The working process of the present invention is:

During drilling, the existing dual-power head drilling rig is used to put the shield pressure relief reaming drill, the spiral blade drill and the sliding guide sleeve 5 together, the spiral blade drill implements spiral slag removal drilling at the bottom of the hole, and the shield pressure relief reaming drill follows the spiral blade drill to perform shield pressure relief reaming drilling. During the drilling process, the screen hole drill rod 2 is used to shield the borehole wall, the screen hole drill rod 2 is used to protect the spiral blade drill rod 3, and the slag discharge screen hole 22 is used to relieve pressure on the screen hole drill rod 2. On the one hand, the shield pressure relief drill can be prevented from being crushed to death, and on the other hand, the spiral blade drill can be prevented from sucking and getting stuck. The spiral blade drill is ahead of the reaming drill bit by a drill rod or a distance of 200mm-300mm. Compared with the traditional single spiral blade drill, the length of the spiral blade drill under the shield pressure relief protection is reduced by a hundred times, so the spiral blade drill can be fundamentally avoided from sucking and getting stuck.

When the drill is withdrawn, after the drilling work is completed, when the spiral blade drill tool withdraws from the screen hole drill rod 2, the shear pin 6 is sheared off, and the sliding guide sleeve 5 withdraws from the hole together with the spiral blade drill tool. In order to ensure that the changing guide sleeve is unobstructed during the withdrawal process, the screen hole drill rod 2 needs to maintain a constant inner diameter, that is, the inner diameter of the thread overlap is equal to the inner diameter of the middle part of the rod body.

This embodiment does not impose any formal limitation on the shape, material, structure, etc. of the present invention. Any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

In the description of the present invention, it is necessary to understand that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection content of the present invention.

If the words "first", "second", etc. are used in this document to limit components, those skilled in the art should know that the use of "first" and "second" is only to facilitate the description of the present invention and simplify the description. Unless otherwise stated, the above words have no special meaning.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (5)

1. The double-power shield pressure relief spiral deslagging combined drilling tool for the protruding coal seam is characterized by comprising a shield pressure relief reaming drilling tool, a spiral blade drilling tool and a sliding guide sleeve which are matched in a penetrating way,

The shield pressure relief reaming drilling tool comprises a plurality of sieve pore drilling rods and a hollow reaming bit, the spiral blade drilling tool comprises a plurality of spiral blade drilling rods and a common bit, and the sliding guide sleeve is arranged in an inner hole of the hollow reaming bit by utilizing a shearing pin;

During drilling, the spiral blade drilling tool performs spiral slag discharging drilling at the bottom of the hole, the shield pressure relief reaming drilling tool performs shield pressure relief reaming drilling immediately after the spiral blade drilling tool performs spiral slag discharging at the inner cavity of the sieve pore drilling rod; when the drill is withdrawn, the spiral blade drilling tool and the sliding guide sleeve are withdrawn from the inner cavity of the shield protection pressure relief reaming drilling tool;

The outer surface of the sieve pore drill rod is provided with a reverse spiral groove, a plurality of slag discharging sieve pores penetrating through the wall thickness of the sieve pore drill rod are arranged in the spiral groove, and spiral taper hole laths are welded in the spiral groove;

The screw blade drill pipes are connected in a plug-in mode, the mesh drill pipes are connected through screw threads, and when the screw blade drill pipe is in operation, the screw blade drill pipe rotates in the forward direction, and the shield pressure relief reaming drill pipe rotates in the reverse direction.

2. The protruding coal seam double-power shield pressure relief spiral deslagging combined drilling tool according to claim 1, wherein the outer diameter of the mesh drill rod is equal to or smaller than the outer diameter of the hollow reaming drill bit, the mesh drill rod plays a role of shielding a borehole wall, and collapse of the borehole wall is restrained.

3. The protruding coal seam double-power shield pressure relief spiral deslagging combined drilling tool according to claim 2, wherein a plurality of taper holes are formed in the spiral taper hole lath, the small diameter of each taper hole is smaller than the diameter of each deslagging sieve hole, and the large diameter of each taper hole is equal to the diameter of each deslagging sieve hole, so that the diameter of a slag inlet of each deslagging sieve hole is smaller than the diameter of a slag outlet; the number of the taper holes on the spiral taper hole lath is equal to that of the slag discharging sieve holes and is coaxially compared with that of the slag discharging sieve holes; the thickness of the spiral taper hole lath is smaller than the depth of the spiral groove; the slag discharging sieve holes have pressure relief effect on the sieve hole drill rod.

4. The double-power shield pressure relief spiral deslagging combined drilling tool for the protruding coal seam of claim 3, wherein a shear pin is adopted to connect a sliding guide sleeve arranged in an inner cavity of the hollow reaming bit with the hollow reaming bit, and the sliding guide sleeve enables the hollow reaming bit to be coaxial with a spiral blade drill rod.

5. The protruding coal seam double-power shield pressure relief spiral deslagging combined drilling tool according to claim 4, wherein the outer diameter of the sliding guide sleeve is equal to the inner diameter of a hollow reaming bit, the inner diameter of the hollow reaming bit is equal to the inner diameter of a sieve pore drill rod, the inner diameter of the sliding guide sleeve is equal to the outer diameter of a spiral blade drill rod, and the outer diameter of the common drill bit is larger than the inner diameter of the sliding guide sleeve and smaller than the outer diameter of the sliding guide sleeve; when the spiral blade drilling tool exits from the inner cavity of the shield pressure relief reaming drilling tool, the shearing pin is sheared, and the sliding guide sleeve exits from the hole along with the spiral blade drilling tool.