A dual-purpose drill bit for drilling operations and screen installation operations.

Abstract

This invention provides a dual-purpose drill bit for both drilling and screen pipe lowering operations. The drill bit body includes a main blade fixedly mounted on its axial front portion, and multiple movable openable / closeable blades movably mounted on the same axial front portion. These openable / closeable blades and main blades are staggered and can move radially. Multiple return springs are installed on the axial front portion of the drill bit body, and these return springs are connected to the openable / closeable blades. After normal drilling operations are completed, this dual-purpose drill bit can be directly lowered into the screen pipe along the inner bore of the large-diameter drill rod without needing to lift the drill bit and replace and lower the screen pipe lowering tool. This improves construction efficiency, reduces worker labor intensity, and provides technical equipment support for gas extraction in soft, easily collapsible coal seams.

Description

Technical Field

[0001] This invention belongs to the field of coal mine underground drilling equipment technology, and relates to drill bits, specifically a dual-purpose drill bit for drilling operations and screen pipe installation operations. Background Technology

[0002] Gas drainage technology is an effective means of preventing coal mine gas outbursts. Current gas pre-drainage technologies, such as cross-beam and in-beam drainage, are widely used in coal mines and have achieved good results, effectively ensuring coal mine safety. However, problems such as severe borehole collapse, short gas drainage time, low gas concentration, and small flow rate in complex geological conditions, such as in soft and fractured coal seams, urgently need to be addressed.

[0003] The current construction methods used for gas drainage holes in fractured and soft coal seams have the following main drawbacks:

[0004] First, lowering the screen pipe requires first retrieving the drill string, which is inefficient. If conventional drill bits are used to construct gas extraction holes, the general construction process after completion is either: "constructing the gas extraction hole → retrieving the drill string → lowering the screen pipe drill string → lowering the screen pipe into the hole → retrieving the drill string," or "constructing the gas extraction hole → retrieving the drill string → lowering the screen pipe into the open hole." Both of these methods require retrieving the drill string before lowering the screen pipe, resulting in high labor intensity and low work efficiency for workers.

[0005] Second, the screen tube insertion rate is low when running through the open borehole. When running the screen tube along the open borehole, the insertion resistance is high due to factors such as drill cuttings deposition in the borehole and borehole bending, resulting in a low overall screen tube insertion rate. Summary of the Invention

[0006] In view of the defects and deficiencies of the existing technology, the purpose of this invention is to provide a dual-purpose drill bit for drilling operations and screen pipe lowering operations, thereby solving the technical problem that the drilling tool needs to be pulled out first when lowering the screen pipe, resulting in low construction efficiency.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A dual-purpose drill bit for drilling and screen pipe installation includes a drill bit body. Multiple main cutter wing mounting slots are evenly distributed along the circumferential direction on the axial front portion of the drill bit body, and main cutter wings are fixedly installed within the main cutter wing mounting slots. Multiple spring mounting slots are evenly distributed along the circumferential direction on the axial front portion of the drill bit body, and openable / closable cutter wings are movably installed within the spring mounting slots. The openable / closable cutter wings and main cutter wings are staggered, and the openable / closable cutter wings can move along the radial direction.

[0009] Multiple spring stop mounting holes are provided at the axial front edge of the drill bit body. The spring stop mounting holes and spring mounting slots are aligned and connected. A spring stop is fixedly installed in the spring stop mounting hole, and a return spring is provided in the spring mounting slot. The radial inner end of the return spring is connected to the axial rear end of the openable and closable blade, and the radial outer end of the return spring is connected to the spring stop.

[0010] The drill bit body has a drill bit center cavity at its center along the axial direction, and multiple drill bit water passage holes are formed inside the drill bit body, which are evenly distributed along the circumferential direction; the openable and closable cutter wing has openable and closable cutter wing water passage holes inside.

[0011] When the openable and closable blades are located at the center of the drill bit body, the return spring is in the extended state, and multiple openable and closable blades are in contact with each other and can completely cover the axial front end of the drill bit center cavity. The drill bit center cavity is connected to the drill bit water passage hole and to the water passage hole of the openable and closable blades. At this time, the dual-purpose drill bit is used as a full-range drill bit for normal drilling operations.

[0012] When the openable and closable blades move to the edge of the drill bit body, the return spring is in a compressed state, the multiple openable and closable blades do not contact each other and the axial front end of the drill bit center cavity is in an open state. The drill bit center cavity is connected to the drill bit water passage hole but not connected to the water passage hole of the openable and closable blades. At this time, the dual-purpose drill bit is used as an openable and closable drill bit for the screen pipe protection hole operation.

[0013] The present invention also has the following technical features:

[0014] The number of main blades is six, and the included angle between two adjacent main blades is 60°; the number of openable / closeable blades is six, and the included angle between two adjacent openable / closeable blades is 60°; the number of reset springs and spring stops is six each.

[0015] The drill bit body includes an integrated drill bit body crown and a drill bit body rear section from front to back. The drill bit body crown is provided with a main cutter wing mounting groove, a spring mounting groove, and a spring stop block mounting hole. The drill bit body rear section is threaded and connected to the drill rod.

[0016] The opening of the water passage hole at one end of the drill bit is located on the axial front end face of the crown of the drill bit body, and the opening of the water passage hole at the other end of the drill bit is located on the inner wall of the rear part of the drill bit body and is connected to the central cavity of the drill bit.

[0017] The connecting surface between the crown of the drill bit body and the outer side of the rear part of the drill bit body is the drill bit connecting surface, and the cone angle of the drill bit connecting surface is 45°.

[0018] The drill bit central cavity includes a first drill bit cavity and a second drill bit cavity connected sequentially from front to back; the first drill bit cavity is connected to the drill bit water passage hole; and the second drill bit cavity is connected to the central flow channel of the drill rod.

[0019] The main blade includes a cutting tooth fixing part, a main blade body and a main blade mounting part, which are integrated from front to back; the cutting tooth fixing part has a cutting tooth recess on the axial front part, and a first cutting tooth and a pair of second cutting teeth are fixedly arranged in the cutting tooth recess; the main blade mounting part is installed in the main blade mounting groove.

[0020] The outer surfaces of the cutting tooth fixing part, the main blade body, and the main blade mounting part are the outer arc surfaces of the main blade; the inner surfaces of the cutting tooth fixing part and the main blade body are the inner curved surfaces of the main blade; the inner surface of the main blade mounting part is the inner arc surface of the main blade; and the axial front end face of the main blade body is the trimming surface of the main blade.

[0021] The openable / closeable blade includes a cutting blade fixing part, an openable / closeable blade body, an openable / closeable blade connecting rod, and a spring connecting block, all integrated from front to back. A cutting blade is fixed to the side of the cutting blade fixing part, and the cutting blade is inclined. The spring connecting block is movably disposed in the spring mounting groove and connected to the radial inner end of the return spring.

[0022] The rear of the openable / closable cutter wing body is an openable / closable cutter wing arc surface. The opening at one end of the water passage hole of the openable / closable cutter wing is located on the front end face of the openable / closable cutter wing body, and the opening at the other end of the water passage hole of the openable / closable cutter wing is located on the openable / closable cutter wing arc surface. When the openable / closable cutter wing is located at the center of the drill bit body, the multiple openable / closable cutter wing arc surfaces form a closed arc surface. The maximum diameter of the closed arc surface is larger than the diameter of the first cavity of the drill bit, and it can completely cover the axial front end of the drill bit center cavity.

[0023] The openable and closable blade includes a first side surface and a second side surface, both of which are connected to the arc surface of the openable and closable blade. The included angle between the first side surface and the second side surface is 60°.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] (I) The dual-purpose drill bit structure of the present invention is ingeniously designed. When the openable and closable blade is located at the center of the drill bit body, the drill bit is used as a full-size drill bit and is used for normal drilling operations. When the openable and closable blade is pushed open by the screen pipe suspension device and is located at the edge of the drill bit body, the drill bit is used as an openable and closable drill bit and is used for screen pipe protection operations. After the screen pipe protection operations are completed, the openable and closable blade will automatically reset under the traction of the reset spring, without the need for manual reset.

[0026] After normal drilling operations are completed, the dual-purpose drill bit of this invention can be directly lowered into the screen pipe along the inner hole of the large-diameter drill rod without the need to lift the drill and replace and lower the screen pipe drill bit. This improves construction efficiency, reduces the labor intensity of workers, and provides technical equipment support for gas extraction in soft and easily collapsible coal seams.

[0027] (II) When using the dual-purpose drill bit of the present invention for screen pipe installation, the large-diameter drill rod can be used to protect the screen pipe, so that the screen pipe is no longer affected by factors such as drill cuttings deposition in the hole and borehole bending, and the screen pipe installation rate can reach 100%. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of a dual-purpose drill bit used for drilling operations and screen pipe installation operations.

[0029] Figure 2 This is a front view of a dual-purpose drill bit used for both drilling and screen installation.

[0030] Figure 3 This is a cross-sectional view of a dual-purpose drill bit used for both drilling and screen installation.

[0031] Figure 4 This is a schematic diagram of the drill bit body.

[0032] Figure 5 This is a schematic diagram of the main blade wing body.

[0033] Figure 6 This is a schematic diagram of the main blade.

[0034] Figure 7 Schematic diagram of the main blade (and) Figure 6 (Different perspectives)

[0035] Figure 8 This is a schematic diagram of the openable and closable blade.

[0036] Figure 9 A schematic diagram of the structure of the openable and closable blade (and) Figure 8 (Different perspectives)

[0037] Figure 10 This is a schematic diagram of the structure of a dual-purpose drill bit used in screen pipe installation.

[0038] Figure 11 This is a cross-sectional view of a dual-purpose drill bit used during screen pipe installation.

[0039] The meanings of the labels in the diagram are as follows: 1-Drill bit body, 2-Main blade, 3-Openable / closable blade, 4-Reset spring, 5-Spring stop, 6-Screen tube suspension device, 7-Screen tube.

[0040] 101-Main blade mounting slot, 102-Spring mounting slot, 103-Spring stop block mounting hole, 104-Drill bit center cavity, 105-Drill bit water passage hole, 106-Drill bit body crown, 107-Drill bit body rear, 108-Drill bit connecting surface.

[0041] 201-Cutting tooth fixing part, 202-Main blade body, 203-Main blade mounting part, 204-Cutting tooth socket, 205-First cutting tooth, 206-Second cutting tooth, 207-Outer arc surface of main blade, 208-Inner curved surface of main blade, 209-Inner arc surface of main blade, 210-Trimming surface of main blade.

[0042] 301-Openable and closable blade water passage hole, 302-Cutting blade fixing part, 303-Openable and closable blade body, 304-Openable and closable blade connecting rod, 305-Spring connecting block, 306-Cutting blade, 307-Openable and closable blade arc surface, 308-Openable and closable blade first side, 309-Openable and closable blade second side.

[0043] 10401 - Drill bit first chamber, 10402 - Drill bit second chamber.

[0044] The technical solution of the present invention will be further described below with reference to the embodiments. Detailed Implementation

[0045] It should be noted that all components and devices used in this invention, unless otherwise specified, are those known in the art. For example, the screen tube suspension device 6 is a conventional screen tube suspension device known in the prior art.

[0046] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0047] Example:

[0048] This embodiment provides a dual-purpose drill bit for both drilling operations and screen pipe installation operations, such as... Figures 1 to 4As shown, the drill bit body 1 includes a drill bit body 1; a plurality of main blade mounting slots 101 are provided on the axial front part of the drill bit body 1, the plurality of main blade mounting slots 101 are evenly distributed along the circumferential direction, and a main blade 2 is fixedly installed in the main blade mounting slot 101; a plurality of spring mounting slots 102 are provided on the axial front part of the drill bit body 1 along the radial direction, the plurality of spring mounting slots 102 are evenly distributed along the circumferential direction, and an openable / closable blade 3 is movably installed in the spring mounting slot 102, the openable / closable blade 3 and the main blade 2 are staggered, and the openable / closable blade 3 can move along the radial direction.

[0049] like Figures 1 to 4 As shown, multiple spring stop mounting holes 103 are provided at the axial front edge of the drill bit body 1. The spring stop mounting holes 103 and the spring mounting grooves 102 are opposite to each other and connected. A spring stop 5 is fixedly installed in the spring stop mounting hole 103, and a return spring 4 is provided in the spring mounting groove 102. The radial inner end of the return spring 4 is connected to the axial rear end of the openable and closable blade 3, and the radial outer end of the return spring 4 is connected to the spring stop 5.

[0050] like Figure 2 and Figure 3 As shown, a drill bit center cavity 104 is provided at the center of the drill bit body 1 along the axial direction, and multiple drill bit water passage holes 105 are provided inside the drill bit body 1. The multiple drill bit water passage holes 105 are evenly distributed along the circumferential direction; and an openable and closable cutter wing 3 is provided inside the cutter wing water passage hole 301.

[0051] When the openable / closeable blade 3 is located at the center of the drill bit body 1, the return spring 4 is in the extended state, and the multiple openable / closeable blades 3 are in contact with each other and can completely cover the axial front end of the drill bit center cavity 104. The drill bit center cavity 104 is connected to the drill bit water passage hole 105 and to the openable / closeable blade water passage hole 301. At this time, the dual-purpose drill bit is used as a full-range drill bit for normal drilling operations.

[0052] When the openable / closeable blade 3 moves to the edge of the drill body 1, the return spring 4 is in a compressed state, the multiple openable / closeable blades 3 do not contact each other and the axial front end of the drill center cavity 104 is in an open state. The drill center cavity 104 is connected to the drill water passage hole 105 but not connected to the openable / closeable blade water passage hole 301. At this time, the dual-purpose drill bit is used as an openable / closeable drill bit for the screen pipe protection hole operation.

[0053] In this embodiment, the openable and closable blade 3 and the main blade 2 are arranged alternately to ensure that the openable and closable blade 3 does not collide or interfere with the main blade 2 during movement.

[0054] As one specific solution in this embodiment, such as Figure 2As shown, there are six main blade wings 2, and the included angle between two adjacent main blade wings 2 is 60°; there are six openable / closeable blade wings 3, and the included angle between two adjacent openable / closeable blade wings 3 is 60°; there are six return springs 4 and six spring stops 5.

[0055] As one specific solution in this embodiment, such as Figure 4 As shown, the drill bit body 1 includes an integrally formed drill bit body crown 106 and drill bit body rear portion 107 from front to back. The drill bit body crown 106 has a main cutter wing mounting groove 101, a spring mounting groove 102, and a spring stop block mounting hole 103. The axial cross-section of the main cutter wing mounting groove 101 is a fan-shaped surface. The spring mounting groove 102 gradually widens from the axial front end to the axial rear end. The spring stop block mounting hole 103 has a cylindrical structure, and the diameter of the spring stop block mounting hole 103 is smaller than the depth of the spring mounting groove 102. The drill bit body rear portion 107 is threaded and connected to the drill rod. In this embodiment, the main cutter wing 2 is fixed in the pre-reserved main cutter wing mounting groove 101 on the drill bit body 1 by welding.

[0056] As one specific solution in this embodiment, such as Figure 4 As shown, the opening of the drill bit water passage hole 105 at one end is located on the axial front end face of the drill bit body crown 106, and the opening of the drill bit water passage hole 105 at the other end is located on the inner wall of the drill bit body rear part 107 and is connected to the drill bit central cavity 104.

[0057] As one specific solution in this embodiment, such as Figure 1 and Figure 3 As shown, the connecting surface of the outer side of the crown 106 of the drill bit body and the rear part 107 of the drill bit body is the drill bit connecting surface 108. The drill bit connecting surface 108 is a frustum surface with a cone angle of 45°.

[0058] As one specific solution in this embodiment, such as Figure 3 As shown, the drill bit central cavity 104 includes a drill bit first cavity 10401 and a drill bit second cavity 10402 connected sequentially from front to back; the drill bit first cavity 10401 is a cylindrical structure and is connected to the drill bit water passage 105; the drill bit second cavity 10402 is a frustum-shaped structure and is connected to the central flow channel of the drill rod.

[0059] As one specific solution in this embodiment, such as Figure 5 and Figure 6As shown, the main blade 2 includes a cutting tooth fixing part 201, a main blade body 202, and a main blade mounting part 203, which are integrated from front to back. A cutting tooth recess 204 is provided on the axial front part of the cutting tooth fixing part 201. A first cutting tooth 205 and a pair of second cutting teeth 206 are fixedly arranged in the cutting tooth recess 204. The first cutting tooth 205 has a cylindrical structure, and the second cutting tooth 206 has a partially cylindrical structure. The main blade mounting part 203 is installed in the main blade mounting groove 101.

[0060] In this embodiment, the first cutting tooth 205 and a pair of second cutting teeth 206 are made of conventional alloy materials known in the prior art.

[0061] As one specific solution in this embodiment, such as Figures 5 to 7 As shown, the outer surfaces of the cutting tooth fixing part 201, the main blade body 202, and the main blade mounting part 203 are the outer arc surface 207 of the main blade; the inner surfaces of the cutting tooth fixing part 201 and the main blade body 202 are the inner curved surface 208 of the main blade; the inner surface of the main blade mounting part 203 is the inner arc surface 209 of the main blade; the axial front end surface of the main blade body 202 is the trimming surface 210 of the main blade, and the trimming surface 210 of the main blade is a fan-shaped surface.

[0062] As one specific solution in this embodiment, such as Figure 8 and Figure 9 As shown, the openable / closable blade 3 includes a cutting blade fixing part 302, an openable / closable blade body 303, an openable / closable blade connecting rod 304, and a spring connecting block 305, all integrated from front to back. A cutting blade 306 is fixed to the side of the cutting blade fixing part 302, and the cutting blade 306 is inclined. The spring connecting block 305 is movably disposed in the spring mounting groove 102 and connected to the radial inner end of the return spring 4. In this embodiment, the cutting blade 306 is fixed to the cutting blade fixing part 302 by welding, and the cutting blade 306 is made of a conventional alloy material known in the prior art.

[0063] As one specific solution in this embodiment, such as Figure 9 As shown, the rear of the openable and closable cutter blade body 303 is the openable and closable cutter blade arc surface 307. The opening of one end of the openable and closable cutter blade water passage hole 301 is located on the front end face of the openable and closable cutter blade body 303, and the opening of the other end of the openable and closable cutter blade water passage hole 301 is located on the openable and closable cutter blade arc surface 307. When the openable and closable cutter blade 3 is located at the center of the drill bit body 1, the multiple openable and closable cutter blade arc surfaces 307 form a closed arc surface. The maximum diameter of the closed arc surface is larger than the diameter of the drill bit first cavity 10401, and it can completely cover the axial front end of the drill bit central cavity 104.

[0064] As one specific solution in this embodiment, such as Figure 9As shown, the openable / closeable blade 3 includes a first openable / closeable blade side 308 and a second openable / closeable blade side 309. Both the first openable / closeable blade side 308 and the second openable / closeable blade side 309 are connected to the arc surface 307 of the openable / closeable blade. Both the first openable / closeable blade side 308 and the second openable / closeable blade side 309 are curved surfaces. The included angle between the first openable / closeable blade side 308 and the second openable / closeable blade side 309 is 60°.

[0065] The working process of this invention is as follows:

[0066] Step 1, Drill bit connection: Connect the dual-purpose drill bit used for drilling and screen pipe installation to the large-diameter drill rod, and connect the water supply device to the rear end. In the initial state, the openable cutter blade 3 is located at the center of the drill bit body 1.

[0067] Step 2, Normal Drilling: After connecting the drill bit, proceed with normal drilling. Flushing fluid is introduced into the drill bit; the pressure of the flushing fluid is low and insufficient to open the closable cutter wings 3. The flushing fluid is delivered to the drill bit along the inner bore of the large-diameter drill pipe and then splits into two paths. One path sequentially flows through the second cavity 10402, the first cavity 10401, and the water passage 105 of the drill bit to the outside of the drill bit, providing cooling for the main cutter wings 2 and carrying away drill cuttings. The other path sequentially flows through the second cavity 10402, the first cavity 10401, and the water passage 301 of the closable cutter wings to the outside of the drill bit, providing cooling for the closable cutter wings 3 and carrying away drill cuttings.

[0068] Step 3, without lifting the drill bit into the screen tube: (e.g.) Figure 10 and Figure 11 As shown, after drilling is completed, the drill bit is pulled out 30-50cm from the bottom of the hole. The screen pipe 7 with the screen pipe suspension device 6 is sent into the bottom of the hole through the inner hole of the large-diameter drill rod using manual or mechanical means. When the spherical top of the screen pipe suspension device 6 contacts the arc surface 307 of the openable and closable blade 3, the radial force decomposed from the axial force pushes the six openable and closable blades 3 to move outward in the radial direction at the same time, so that the drill bit center cavity 104 opens, and the screen pipe suspension device 6 lowers the screen pipe 7 into the borehole through the circular hole channel.

[0069] In this embodiment, the outer diameter of the screen tube 7 is 30mm, the outer diameter of the screen tube suspension device 6 is 32mm, and the inner diameter of the drill bit center cavity 104 is greater than or equal to 36mm, so as to ensure that the screen tube 7 and the screen tube suspension device 6 can pass smoothly.

[0070] Step four: After the screen tube is lowered, the drill is lifted. The openable and closed blade 3 is reset by the elastic force of the return spring 4 for the next use.

Claims

1. A dual-purpose drill bit for drilling operations and screen pipe installation operations, comprising a drill bit body (1), wherein a plurality of main blade mounting grooves (101) are provided on the axial front portion of the drill bit body (1), the plurality of main blade mounting grooves (101) are evenly distributed along the circumferential direction, and main blades (2) are fixedly disposed in the main blade mounting grooves (101); characterized in that: The drill bit body (1) has multiple spring mounting slots (102) on its axial front part along the radial direction. The multiple spring mounting slots (102) are evenly distributed along the circumferential direction. Openable and closable blades (3) are movably arranged in the spring mounting slots (102). The openable and closable blades (3) and the main blades (2) are staggered. The openable and closable blades (3) can move along the radial direction. The drill bit body (1) has multiple spring stop mounting holes (103) at the axial front edge. The spring stop mounting holes (103) and the spring mounting grooves (102) are opposite to each other and connected. A spring stop (5) is fixedly installed in the spring stop mounting hole (103), and a return spring (4) is provided in the spring mounting groove (102). The radial inner end of the return spring (4) is connected to the axial rear end of the openable cutter wing (3), and the radial outer end of the return spring (4) is connected to the spring stop (5). The drill bit body (1) has a drill bit center cavity (104) at the center along the axial direction, and multiple drill bit water passage holes (105) are opened inside the drill bit body (1), and the multiple drill bit water passage holes (105) are evenly distributed along the circumferential direction; the openable and closable cutter wing (3) has an openable and closable cutter wing water passage hole (301). When the openable cutter blade (3) is located at the center of the drill bit body (1), the return spring (4) is in the extended state, and multiple openable cutter blades (3) are in contact and can completely cover the axial front end of the drill bit center cavity (104). The drill bit center cavity (104) is connected to the drill bit water passage hole (105) and to the openable cutter blade water passage hole (301). At this time, the dual-purpose drill bit is used as a full-range drill bit for normal drilling operations. When the openable and closable blades (3) move to the edge of the drill body (1), the return spring (4) is in a compressed state, the multiple openable and closable blades (3) do not contact each other and the axial front end of the drill center cavity (104) is in an open state. The drill center cavity (104) is connected to the drill water passage hole (105) and not connected to the openable and closable blade water passage hole (301). At this time, the dual-purpose drill bit is used as an openable and closable drill bit for the screen pipe protection hole operation. The openable / closeable blade (3) includes a cutting blade fixing part (302) integrated from front to back, an openable / closeable blade body (303), an openable / closeable blade connecting rod (304), and a spring connecting block (305); a cutting blade (306) is fixed on the side of the cutting blade fixing part (302), and the cutting blade (306) is inclined; the spring connecting block (305) is movably disposed in the spring mounting groove (102) and connected to the radial inner end of the return spring (4); The rear of the openable and closable blade body (303) is the openable and closable blade arc surface (307). The opening of one end of the openable and closable blade water passage hole (301) is located on the front end face of the openable and closable blade body (303), and the opening of the other end of the openable and closable blade water passage hole (301) is located on the openable and closable blade arc surface (307). When the openable and closable blade (3) is located at the center of the drill bit body (1), multiple openable and closable blade arc surfaces (307) form a closed arc surface. The maximum diameter of the closed arc surface is greater than the diameter of the first cavity of the drill bit (10401), and it can completely cover the axial front end of the drill bit center cavity (104).

2. The dual-purpose drill bit for drilling operations and screen pipe installation operations as described in claim 1, characterized in that, The number of main blades (2) is six, and the included angle between two adjacent main blades (2) is 60°; the number of openable / closeable blades (3) is six, and the included angle between two adjacent openable / closeable blades (3) is 60°; the number of reset springs (4) and spring stops (5) is six.

3. The dual-purpose drill bit for drilling operations and screen pipe installation operations as described in claim 1, characterized in that, The drill bit body (1) includes a drill bit body crown (106) and a drill bit body rear part (107) integrally arranged from front to back. The drill bit body crown (106) is provided with a main cutter wing mounting groove (101), a spring mounting groove (102) and a spring stop block mounting hole (103); the drill bit body rear part (107) is threaded and connected to the drill rod. The opening of the drill bit water passage hole (105) is located on the axial front end face of the drill bit body crown (106), and the opening of the drill bit water passage hole (105) is located on the inner wall of the drill bit body rear part (107) and is connected to the drill bit center cavity (104).

4. The dual-purpose drill bit for drilling operations and screen pipe installation operations as described in claim 3, characterized in that, The connecting surface of the outer side of the crown (106) and the rear part (107) of the drill bit body is the drill bit connecting surface (108), and the cone angle of the drill bit connecting surface (108) is 45°.

5. The dual-purpose drill bit for drilling operations and screen pipe installation operations as described in claim 1, characterized in that, The drill bit center cavity (104) includes a drill bit first cavity (10401) and a drill bit second cavity (10402) connected sequentially from front to back; the drill bit first cavity (10401) is connected to the drill bit water passage (105); the drill bit second cavity (10402) is connected to the drill rod center flow channel.

6. The dual-purpose drill bit for drilling operations and screen pipe installation operations as described in claim 1, characterized in that, The main blade (2) includes a cutting tooth fixing part (201), a main blade body (202), and a main blade mounting part (203) that are integrated from front to back; the cutting tooth fixing part (201) has a cutting tooth recess (204) on its axial front part, and a first cutting tooth (205) and a pair of second cutting teeth (206) are fixedly arranged in the cutting tooth recess (204); the main blade mounting part (203) is installed in the main blade mounting groove (101).

7. The dual-purpose drill bit for drilling operations and screen pipe installation operations as described in claim 6, characterized in that, The outer surfaces of the cutting tooth fixing part (201), the main blade body (202), and the main blade mounting part (203) are the outer arc surface (207) of the main blade; the inner surfaces of the cutting tooth fixing part (201) and the main blade body (202) are the inner curved surface (208) of the main blade; the inner surface of the main blade mounting part (203) is the inner arc surface (209) of the main blade; and the axial front end surface of the main blade body (202) is the trimming surface (210) of the main blade.

8. The dual-purpose drill bit for drilling operations and screen pipe installation operations as described in claim 1, characterized in that, The openable and closable blade (3) includes an openable and closable blade first side (308) and an openable and closable blade second side (309). Both the openable and closable blade first side (308) and the openable and closable blade second side (309) are connected to the openable and closable blade arc surface (307). The included angle between the openable and closable blade first side (308) and the openable and closable blade second side (309) is 60°.

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