A composite type reamer bit for drilling a well

Abstract

The application discloses a composite reaming drill bit for drilling, which comprises a drill string, a pilot body is arranged on the drill string, a notch is arranged on the front end side wall of the pilot body, a plurality of pilot stabilizing blocks are formed in a surrounding distribution, an annular grid plate is arranged on the drill string and abuts against the pilot body, a plurality of reaming stabilizing blocks are arranged on the outer side wall of the annular grid plate in a surrounding distribution, and a reaming cutter group is arranged on the pilot body between the pilot stabilizing blocks and the annular grid plate to ream the pilot hole. The reaming cutter group and the roller are fixed on the pilot body to form a hard connection, so that reaming is started after drilling is completed. The pilot stabilizing blocks and the reaming stabilizing blocks are arranged to be in contact with the inner wall of the drilled hole before reaming and the inner wall of the drilled hole after reaming respectively, so that a restriction is formed in a two-stage stabilizing mode, smooth drilling is realized with the same drilling and reaming path, and the risk of drill bit falling is lower.

Description

Technical Field

[0001] This invention relates to the field of drilling technology, and more specifically to a composite reaming drill bit for drilling. Background Technology

[0002] Drilling is the process of creating boreholes in the ground using mechanical equipment. It is commonly used in various fields such as exploration and water conservancy projects. During the drilling process, a small drill bit is first used to drill a small-diameter pilot hole in the ground. Then, a large drill bit (reamer) is used to ream the borehole along the path of the pilot hole, thereby achieving the required borehole diameter.

[0003] Currently, in the drilling and reaming process, a tandem drill bit scheme is commonly used. This involves installing a reaming bit behind the directional drill bit that has entered the ground via a flexible connection. The reaming bit is guided by the directional drill bit to move along the pilot hole path, and its reaming blades further enlarge the pilot hole. However, this method of drilling and reaming has the following problems: 1) Because the directional drill bit and the reamer are connected by a soft connection, there is a risk of separation between the directional drill bit and the reamer, and there is also a risk of separation between the reamer and the drilling machinery. Therefore, the probability of the drill bit separation increases after the soft connection is adopted.

[0004] 2) Since the directional drill bit and the reamer are connected by a soft connection, they cannot restrain each other. This causes the directional drill bit to oscillate radially when breaking down rock fragments in the pilot hole. When the radial oscillation amplitudes of the directional drill bit and the reamer are inconsistent, it can easily lead to a difference between the pilot hole and the reamer path, resulting in the reamer failing to meet the requirements or even being unable to continue reaming.

[0005] In summary, the current drilling and reaming construction method uses a double drill bit soft connection, which means that there is no constraint and protection between the two drill bits. This makes it impossible to ensure that the guide hole and the reaming path are consistent, and it also increases the risk of the drill bit falling off. Summary of the Invention

[0006] The purpose of this invention is to provide a composite reaming drill bit for drilling, which solves the technical problem in the prior art where the soft connection of two drill bits in series cannot form a constraint and is prone to displacement when radial vibration occurs, making it impossible to ensure the path of the guide hole reaming and thus failing to achieve the required reaming, and increasing the risk of drill bit falling off.

[0007] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution: A composite reaming drill bit for drilling includes a drill string, a guide body disposed on the drill string, a groove is formed around the front sidewall of the guide body to form a plurality of circumferentially distributed guide and stabilizer blocks, an annular grid plate disposed on the drill string and abutting the guide body, a plurality of reaming and stabilizer blocks are disposed on the outer sidewall of the annular grid plate, and a reaming cutter assembly disposed on the guide body between the guide and stabilizer blocks and the annular grid plate to ream the guide hole; Multiple toothed plates are arranged around the front sidewall of the guide body, and each toothed plate is rotatably provided with a toothed wheel that is inclined towards the center. A chisel is provided in the center of the front end of the guide body, and the chisel cooperates with the multiple toothed wheels to break the rock blocks in the guide hole and to guide the forward direction. The diameter of the guide and straightening block is slightly larger than the distribution diameter of the plurality of toothed cones, so that the guide and straightening block rotates tightly against the inner wall of the guide hole; The diameter of the reaming cutter group is larger than the diameter of the guide and centering block to enlarge the guide hole, and the diameter of the reaming and centering block is slightly smaller than the diameter of the reaming cutter group so that the reaming and centering block rotates against the inner wall of the drill hole after the hole enlargement is completed. The guide block rotates within the guide hole, cooperating with the reaming block to rotate within the borehole, thereby bidirectionally aligning the drill bit and smoothly guiding the reaming process.

[0008] As a preferred embodiment of the present invention, the toothed wheel includes an outer ring wall, which is formed as a stepped layer with a gradually decreasing diameter, and cutter teeth are provided on the side wall of the stepped layer of the outer ring wall at equal intervals.

[0009] In a preferred embodiment of the present invention, the cutting teeth are obliquely disposed on the stepped sidewall of the outer ring wall, and the oblique direction of the cutting teeth is toward the tip of the toothed wheel.

[0010] As a preferred embodiment of the present invention, the palm includes a fan-shaped tile, the fan-shaped tile includes an inner arc wall and an outer arc wall, the inner arc wall is mounted against the guide body through a slot provided thereon, and the outer arc wall is provided with a plurality of wear-resistant protective posts. The outer arc wall and the inner arc wall are arranged coaxially with the guide body.

[0011] As a preferred embodiment of the present invention, a plurality of wear-resistant protective posts are evenly distributed on the outer arc wall, and each of the wear-resistant protective posts is vertically arranged on the outer arc wall, and the height of the plurality of wear-resistant protective posts is equal.

[0012] As a preferred embodiment of the present invention, the fan-shaped tile includes a top end and a bottom end, the top end being disposed on the side wall of the guide body; The bottom end is inclined toward the axis of the guide body, and the toothed wheel is rotatably disposed on the inclined surface of the bottom end.

[0013] As a preferred embodiment of the present invention, the reaming tool assembly includes an annular fixed tool plate disposed on the guide body, and a plurality of reaming tools radiating radially are disposed on the annular fixed tool plate.

[0014] As a preferred embodiment of the present invention, the reaming tool includes a cutting plate, wherein the front drilling side and the reaming side of the cutting plate, which are perpendicular to each other, are both located outside the annular fixed cutting plate; A streamlined transition surface is provided between the front drilling side and the flaring side, and diamond sheets are inlaid on the front drilling side, the flaring side and the transition surface.

[0015] In a preferred embodiment of the present invention, the side of the annular grid plate away from the guide body is configured as an open grid, and the diameter of the annular grid plate is smaller than the diameter of the annular fixed blade plate, and the annular fixed blade plate is fixedly connected to the annular grid plate. The drill string includes a drill shank, and a safety ring is provided at the end of the drill shank. The diameter of the safety ring is larger than the diameter of the drill shank.

[0016] As a preferred embodiment of the present invention, a plurality of reinforcing blocks integrally formed with the guide body are arranged around the front end sidewall of the guide body, and each of the reinforcing blocks is arranged on the rotating back side of the corresponding palm to support the palm. Each of the reinforcing blocks is provided with a drilling water eye, and the reaming cutter group is provided with a plurality of annularly distributed reaming water eyes, and each of the reaming water eyes is provided on the annular fixed cutter plate and close to the corresponding reaming cutter. The drilling water inlet faces the front of the roller cone to flush the bottom of the well, and the reaming water inlet faces the reaming cutter group to flush the reaming cutter to cool it down and remove rock cuttings.

[0017] Compared with the prior art, the present invention has the following advantages: This invention forms a rigid connection by fixing the roller cone and the reamer assembly together on the guide body, so that reaming can begin immediately after drilling is completed. Furthermore, by setting the guide and reaming blocks, they are made to contact the inner wall of the borehole before and after reaming, respectively, to form a constraint in a two-stage stabilization manner, so as to achieve smooth drilling with consistent drilling and reaming paths, and the risk of drill bit falling off is lower. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the composite reaming drill bit for drilling provided in an embodiment of the present invention; Figure 2 for Figure 1 Enlarged view of point A in the middle; Figure 3 for Figure 1 Enlarged view at point B in the middle; Figure 4 This is a schematic diagram of the annular grid portion of the composite borehole reamer bit for drilling provided in an embodiment of the present invention.

[0020] The labels in the diagram represent the following: 1-Drill string; 2-Guide body; 3-Reamer assembly; 4-Tooth; 5-Roller cone; 6-Drill bit; 7-Drill water inlet; 8-Reamer water inlet; 9-Annular grid plate; 11-Drill shank; 12-Safety ring; 21-Groove; 22-Guide block; 23-Reinforcing block; 31-Annular retaining plate; 32-Reamer; 41-Fan-shaped tile; 42-Wear-resistant protective column; 43-Slot; 51-Outer ring wall; 52-Cutting tooth; 91-Reamer block; 321-Cutting plate; 322-Front drilling side; 323-Flanging side; 324-Transition surface; 325-Diamond sheet; 411-Inner arc wall; 412-Outer arc wall; 413-Top end; 414-Bottom end. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figure 1As shown, the present invention provides a composite reaming drill bit for drilling, including a drill string 1, a guide body 2 disposed on the drill string 1, a groove 21 is formed around the front side wall of the guide body 2, and a plurality of circumferentially distributed guide and straightening blocks 22 are formed, an annular grid plate 9 is disposed on the drill string 1 and abuts against the guide body 2, and a plurality of reaming and straightening blocks 91 are disposed around the outer side wall of the annular grid plate 9, and a reaming cutter group 3 is disposed on the guide body 2 between the guide and straightening blocks 22 and the annular grid plate 9 to ream the guide hole; Multiple toothed plates 4 are arranged around the front side wall of the guide body 2. Each toothed plate 4 is rotatably equipped with a toothed wheel 5 that is inclined towards the center. A chisel 6 is arranged in the center of the front end of the guide body 2. The chisel 6 works with the multiple toothed wheels 5 to break the rock blocks in the guide hole and to guide the forward direction. The diameter of the guide and straightening block 22 is slightly larger than the distribution diameter of the multiple toothed wheels 5, so that the guide and straightening block 22 rotates tightly against the inner wall of the guide hole; The diameter of the reaming cutter group 3 is larger than the diameter of the guide and centering block 22 to enlarge the guide hole, and the diameter of the reaming and centering block 91 is slightly smaller than the diameter of the reaming cutter group 3 so that the reaming and centering block 91 rotates against the inner wall of the drill hole after the hole is enlarged. The guide and straightening block 22 rotates in the guide hole and cooperates with the reaming and straightening block 91 to rotate in the drill hole, so as to straighten the drill bit in both directions and smoothly guide and ream the hole.

[0023] The reaming drill bit of this embodiment mainly utilizes multiple rotatable roller cones 5 arranged in a ring to cooperate with the drill bit 6 for guided drilling. During the drilling process, the borehole is directly enlarged by secondary drilling through the reaming cutter 3. During the drilling and reaming process, multiple guiding and straightening blocks 22 rotate close to the inner wall of the guiding hole to form a first-level straightening, and multiple reaming and straightening blocks 91 rotate close to the inner wall of the borehole (the guiding hole is enlarged to form a qualified borehole) to form a second-level straightening. That is, by using the two-level straightening drilling method, the radial oscillation of the drill bit is reduced, thereby making the drill bit stably guided and reamed.

[0024] The drill bit 6 is located at the front end, which can effectively break up and remove large pieces of rock debris from the guide hole, reducing the risk of blockage.

[0025] During the hole enlargement and alignment process, the roller wheel 5 rotates along with the guide body 2, while also rotating due to frictional resistance. As it rotates, the roller wheel 5 cuts the rock fragments that fall into the guide hole, quickly breaking up large rock chips with low power consumption. Furthermore, the coordinated rotation of multiple roller wheels 5 enables the rapid crushing of large rock fragments into smaller pieces. Therefore, a preferred embodiment is provided below to enable the roller wheel 5 to quickly crush the rock fragments falling into the guide hole into small pieces.

[0026] like Figure 1 and Figure 2As shown, the toothed gear 5 includes an outer ring wall 51, which is formed by a stepped layer with a gradually decreasing diameter, and cutter teeth 52 are provided on the side wall of the stepped layer of the outer ring wall 51.

[0027] When the tooth 52 rotates around the toothed wheel 5 (and rotates synchronously with the guide body 2), it applies shearing force to the falling rock and crushes the rock by cutting. Since the outer ring wall 51 of the toothed wheel 5 adopts a stepped layout, when the toothed wheel 5 rotates, it can make the tooth 52 gradually grind the rock fragments from large rock blocks into small fragments.

[0028] Specifically, the drill bit 6 initially breaks up the rock fragments that have fallen into the guide hole and pushes the broken rock fragments away from the guide hole. The pushed-away rock fragments are located in the advancing area of ​​the gear 5. The rotation of the gear 5 will then break up the rock fragments again, improving the effect of clearing the fallen rock fragments.

[0029] Furthermore, such as Figure 2 As shown, the cutting teeth 52 are inclinedly disposed on the stepped sidewall of the outer ring wall 51, and the inclined direction of the cutting teeth 52 is towards the tip of the toothed wheel 5.

[0030] The cutting teeth 52 are tilted outward and toward the tip of the toothed wheel 5. When the toothed wheel 5 revolves and rotates, the contact area between the cutting teeth 52 and the rock is reduced, thereby increasing the pressure of the cutting teeth 52 on the rock and achieving the effect of quickly breaking the rock.

[0031] Furthermore, the closer to the inner wall of the guide hole, the smaller the distance between the roller 5 and the inner wall of the guide hole, the smaller the particles formed after the rock fragments are broken by the roller 5, thus improving the breaking effect of the roller 5 and further improving the effect of clearing the fallen rock fragments.

[0032] The toothed pads 4 are used to assemble and fix the toothed wheels 5, and the toothed wheels 5 are distributed around the guide body 2. When the guide body rotates, the multiple toothed pads 4 rotate synchronously with the guide body. In order to avoid the toothed pads 4 from rubbing against the inner wall of the guide hole during rotation and causing wear, the following preferred embodiment is provided to protect the outer surface of the toothed pads 4 and to correct the guide hole of the toothed wheel 5 to ensure that the diameter of the guide hole does not shrink.

[0033] like Figure 1 and Figure 2 As shown, the toothed palm 4 includes a fan-shaped tile 41, which includes an inner arc wall 411 and an outer arc wall 412. The inner arc wall 411 is installed against the guide body 2 through a slot 43 provided thereon, and multiple wear-resistant protective posts 42 are provided on the outer arc wall 412. The outer arc wall 412 and the inner arc wall 411 are arranged coaxially with the guide body 2.

[0034] The wear-resistant protective post 42 is set on the outer arc wall 412 of the fan-shaped tile 41, and the outer arc wall 412 is set coaxially with the guide body 2. That is, the rotation axis of the wear-resistant protective post 42 is the same as the rotation axis of the guide body 2. The wear-resistant protective post 42 rotates and contacts the inner wall of the guide hole, thereby avoiding the outer arc wall 412 from directly contacting the inner wall of the guide hole and rotating and wearing, thus improving the service life of the tooth palm 4.

[0035] Furthermore, the wear-resistant protective column 42 rotates and cuts the uneven parts of the inner wall of the guide hole to correct the flatness of the inner wall of the guide hole and ensure that the inner diameter of the drill hole does not shrink, so as to facilitate the hole enlarging by the hole enlarging tool group 3.

[0036] Furthermore, such as Figure 2 As shown, multiple wear-resistant protective posts 42 are evenly distributed on the outer arc wall 422, and each wear-resistant protective post 42 is vertically set on the outer arc wall 412, and the height of the multiple wear-resistant protective posts 42 is equal.

[0037] Wear-resistant protective pillars 42 are evenly distributed on the outer arc wall 422, so that the axis of each wear-resistant protective pillar 42 is perpendicular to the axis of the guide body 2. Since the height of multiple wear-resistant protective pillars 42 is equal, when multiple tooth palms 4 rotate, multiple wear-resistant protective pillars 42 form uniform wear protection for each tooth palm 4.

[0038] Furthermore, when multiple toothed palms 4 rotate, the wear-resistant protective pillars 42 rotate and grind with a fixed diameter, thereby correcting the inner wall of the guide hole, making the inner wall of the guide hole more smoothly cut, and improving the effect of drilling and enlarging.

[0039] like Figure 2 As shown, the fan-shaped tile 41 includes a top end 413 and a bottom end 414, with the top end 413 disposed on the side wall of the guide body 2; The bottom end 414 is inclined toward the axis of the guide body 2, and the toothed wheel 5 is rotatably mounted on the inclined surface of the bottom end 414.

[0040] When the toothed wheel 5 is rotated and installed on the inclined surface of the bottom end 414, the toothed wheel is in an inward tilted state. This creates a gap between the toothed wheel 5 and the inner wall of the guide hole in front, which is constantly decreasing. This allows the toothed wheel 5 to gradually squeeze and cut the rock blocks initially broken by the drill bit 6 into smaller gravel particles, thus improving the effect of cleaning the rock blocks that have fallen into the guide hole.

[0041] The reamer assembly 3 is used to enlarge the diameter of the drilled hole. The following is a preferred embodiment so that the reamer assembly 3 can gradually scrape and enlarge the diameter of the guide hole.

[0042] like Figure 1 and Figure 3 As shown, the reaming tool assembly 3 includes an annular fixed tool plate 31 disposed on the guide body 2, and a plurality of reaming tools 32 radiating radially are disposed on the annular fixed tool plate 31.

[0043] When the guide body 2 rotates, the annular fixed blade plate 31 rotates synchronously. The rotation of the annular fixed blade plate 31 drives the multiple reaming tools 32 on it to rotate synchronously. The use of the annular fixed blade plate 31 to fix the reaming tools 32 can provide lateral support force for the reaming tools 32, and prevent the reaming tools 32 from bending during the rotation reaming process, which would lead to a reduction in the reaming diameter.

[0044] Furthermore, such as Figure 3 As shown, the reaming tool 32 includes a cutting plate 321, with the front drilling side 322 and the flaring side 323 of the cutting plate 321 being located at right angles to each other and both located outside the annular fixed cutting plate 31. A streamlined transition surface 324 is provided between the front drilling side 322 and the flaring side 323, and diamond sheets 325 are inlaid on the front drilling side 322, the flaring side 323 and the transition surface 324.

[0045] By using diamond sheets 325 disposed on the front drilling side 322, the flaring side 323 and the transition surface 324, the front end and sidewalls of the borehole can be scraped.

[0046] Furthermore, by setting the transition surface 324, the blade 321 gradually scrapes the inner wall of the guide hole, thereby gradually increasing the inner diameter of the guide hole, reducing the squeezing damage to the inner wall of the guide hole, and avoiding the damage and collapse caused by the large pressure change of the inner wall of the guide hole due to direct diameter expansion.

[0047] like Figure 1 and Figure 4 As shown, the side of the annular grid plate 9 away from the guide body 2 is set as an open grid, and the diameter of the annular grid plate 9 is smaller than the diameter of the annular fixed blade plate 31, and the annular fixed blade plate 31 is fixedly connected to the annular grid plate 9. The drill string 1 includes a drill shank 11, and a safety ring 12 is provided at the end of the drill shank 11. The diameter of the safety ring 12 is larger than the diameter of the drill shank 11.

[0048] The annular grid plate 9 enables multiple hole-reaming and straightening blocks 91 to be distributed around each other and shortens the radial length of the hole-reaming and straightening blocks 91. This reduces the lever effect when the hole-reaming and straightening blocks 91 rotate close to the inner wall of the drilled hole after hole reaming, and prevents obstruction and bending, thus making the secondary straightening more reliable.

[0049] Since the ends of the annular grid plate 9 are open, it can effectively intercept rock blocks from falling into the drill bit gaps inside the borehole, reducing the occurrence of stuck drill accidents and improving the safety of the drill bit at the bottom of the hole. In the event of a block falling from the upper wellbore, the rock will fall into the open grid and then be directly brought out of the wellhead during the tripping process. This prevents large rock blocks from getting stuck between the reaming and straightening block 91 and the annular grid plate 9, greatly reducing the probability of a stuck drill accident.

[0050] By setting a safety ring 12 at the end of the drill shank 11, the handling method for drill bit accidents in the borehole is increased. That is, if a drill bit slippage accident occurs, such as drill shank slippage fatigue, a special drill bit retrieval tool can be directly lowered. The tool has a drill bit straightening tool and a buckle that fits the safety ring 12, which can straighten the drill bit that has fallen to the bottom of the well and retrieve it from the well, thus improving the safety of the drill bit.

[0051] like Figure 1 and Figure 2 As shown, multiple reinforcing blocks 23 integrally formed with the guide body 2 are arranged around the front side wall of the guide body 2. Each reinforcing block 23 is arranged on the rotating back side of the corresponding palm 4 to support the palm 4. Each reinforcing block 23 is provided with a drilling water eye 7, and multiple annularly distributed reaming water eyes 8 are provided on the reaming cutter group 3, and each reaming water eye 8 is provided on the annular fixed cutter plate 31 and close to the corresponding reaming cutter 32. Among them, the drilling water eye 7 faces the front of the roller cone 5 to flush the front of the guide hole and clean the broken rock fragments in the guide hole, and the reaming water eye 8 faces the reaming cutter group 3 to flush the reaming cutter 32 to cool it down and clean the rock cuttings.

[0052] The reinforcing block 23 can provide support for the fan-shaped tile 41. That is, when the fan-shaped tile 41 drives the toothed wheel 5 to rotate, the toothed wheel 5 is resisted by the broken rock, and the fan-shaped tile 41 is resisted. Therefore, the reinforcing block 23 can prevent the fan-shaped tile 41 from bending or breaking after being resisted.

[0053] The groove 21 at the end of the guide body 2 is open on one side, and the tooth 4 and the reinforcing block 23 are both set on the inner wall of the open groove 21.

[0054] Both the borehole water inlet 7 and the reaming water inlet 8 are connected to the drilling fluid supply channel (existing structure, not shown in the figure) inside the drill string 1, so that drilling fluid can be sprayed from the borehole water inlet 7 and the reaming water inlet 8 into the borehole to flush away debris and drill cuttings, and to reduce the temperature of the roller cone 5 and the reaming cutter 32.

[0055] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A composite reamer for drilling a well, characterized in that, The system includes a drill string (1), on which a guide body (2) is provided. A slot (21) is opened around the front side wall of the guide body (2), and multiple guide and straightening blocks (22) are formed around it. An annular grid plate (9) is provided on the drill string (1) and is attached to the guide body (2). Multiple hole-enlarging and straightening blocks (91) are provided on the outer side wall of the annular grid plate (9). A hole-enlarging cutter group (3) is provided on the guide body (2) between the guide and straightening blocks (22) and the annular grid plate (9) to enlarge the guide hole. Multiple toothed plates (4) are arranged around the front side wall of the guide body (2). Each toothed plate (4) is rotatably provided with a toothed wheel (5) that is inclined toward the center. A chisel (6) is provided in the center of the front end of the guide body (2). The chisel (6) works with the multiple toothed wheels (5) to break the rock in the guide hole and to guide the forward direction. The diameter of the guide and straightening block (22) is slightly larger than the distribution diameter of the plurality of toothed wheels (5) so that the guide and straightening block (22) rotates tightly against the inner wall of the guide hole; The diameter of the reaming cutter group (3) is larger than the diameter of the guide and straightening block (22) to ream the guide hole, and the diameter of the reaming and straightening block (91) is slightly smaller than the diameter of the reaming cutter group (3) so that the reaming and straightening block (91) rotates against the inner wall of the drill hole after the reaming is completed. The guide and straightening block (22) rotates in the guide hole and cooperates with the hole-enlarging and straightening block (91) to rotate in the drill hole, so as to straighten the drill bit in both directions and guide the hole enlargement smoothly. The reaming tool assembly (3) includes an annular fixed tool plate (31) disposed on the guide body (2), and a plurality of radially radiating reaming tools (32) are disposed on the annular fixed tool plate (31). The side of the annular grid plate (9) away from the guide body (2) is set as an open grid, and the diameter of the annular grid plate (9) is smaller than the diameter of the annular fixed blade plate (31), and the annular fixed blade plate (31) is fixedly connected to the annular grid plate (9). The drill string (1) includes a drill shank (11), and a safety ring (12) is provided at the end of the drill shank (11). The diameter of the safety ring (12) is larger than the diameter of the drill shank (11).

2. The composite reaming drill bit for drilling according to claim 1, characterized in that, The toothed wheel (5) includes an outer ring wall (51), which is formed by a stepped layer with a gradually decreasing diameter, and has circumferentially distributed cutting teeth (52) on the side wall of the stepped layer of the outer ring wall (51).

3. A composite reaming drill bit for drilling according to claim 2, characterized in that, The cutting teeth (52) are inclinedly disposed on the stepped sidewall of the outer ring wall (51), and the inclined direction of the cutting teeth (52) is toward the tip of the toothed wheel (5).

4. A composite reaming drill bit for drilling according to any one of claims 1-3, characterized in that, The tooth palm (4) includes a fan-shaped tile (41), which includes an inner arc wall (411) and an outer arc wall (412). The inner arc wall (411) is mounted on the guide body (2) by a slot (43) provided thereon, and the outer arc wall (412) is provided with a plurality of wear-resistant protective posts (42). The outer arc wall (412), the inner arc wall (411), and the guide body (2) are arranged coaxially.

5. A composite reaming drill bit for drilling according to claim 4, characterized in that, Multiple wear-resistant protective columns (42) are evenly distributed on the outer arc wall (422), and each wear-resistant protective column (42) is vertically arranged on the outer arc wall (412), and the height of the multiple wear-resistant protective columns (42) is equal.

6. A composite reaming drill bit for drilling according to claim 4, characterized in that, The fan-shaped tile (41) includes a top end (413) and a bottom end (414), the top end (413) being disposed on the side wall of the guide body (2); The bottom end (414) is inclined toward the axis of the guide body (2), and the toothed wheel (5) is rotatably disposed on the inclined surface of the bottom end (414).

7. A composite reaming drill bit for drilling according to claim 1, characterized in that, The reaming tool (32) includes a cutting plate (321), and the front drilling side (322) and the flaring side (323) of the cutting plate (321) are located on the outside of the annular fixed cutting plate (31) at right angles to each other; A streamlined transition surface (324) is provided between the front drilling side (322) and the flaring side (323), and diamond sheets (325) are inlaid on the front drilling side (322), the flaring side (323) and the transition surface (324).

8. A composite reaming drill bit for drilling according to claim 1, characterized in that, Multiple reinforcing blocks (23) integrally formed with the guide body (2) are arranged around the front side wall of the guide body (2). Each reinforcing block (23) is arranged on the rotating back side of the corresponding palm (4) to support the palm (4). Each of the reinforcing blocks (23) is provided with a drilling water eye (7), and a plurality of annularly distributed reaming water eyes (8) are provided on the reaming cutter group (3), and each of the reaming water eyes (8) is provided on the annular fixed cutter plate (31) and close to the corresponding reaming cutter (32). The drilling water eye (7) faces the front of the roller cone (5) to flush the bottom of the well, and the reaming water eye (8) faces the reaming cutter group (3) to flush the reaming cutter (32) to cool it down and to clean the rock cuttings.

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