A PDC drill bit used with an air screw

Abstract

The present invention relates to the technical field of PDC drill bits, and specifically to a PDC drill bit used in conjunction with an air screw, comprising a drill bit body and a drill bit joint, wherein the drill bit body is provided with a main blade from the front end to the side wall, and a plurality of main blades are provided along the circumference of the drill bit body at intervals, and each main blade is provided with a front auxiliary blade and a rear auxiliary blade on opposite sides thereof, respectively, and a main flow channel and a rear auxiliary blade flow channel are provided between the front auxiliary blade and the rear auxiliary blade and the main blade, respectively, and a front auxiliary blade flow channel is provided between two adjacent front auxiliary blades and rear auxiliary blades, and the main flow channel, the rear auxiliary blade flow channel and the front auxiliary blade flow channel are connected at the front end of the drill bit body to form an air outlet, and a replaceable nozzle is installed in the air outlet. A multi-channel design is adopted, and through the design of the main flow channel, the rear auxiliary blade flow channel and the front auxiliary blade flow channel, cooling gas flows through both sides of the main blade, the front auxiliary blade and the rear auxiliary blade during the drilling process, thereby taking away heat and improving the cooling and chip removal effects.

Description

Technical Field

[0001] The present invention relates to the technical field of PDC drill bits, and in particular to a PDC drill bit used in conjunction with an air screw. Background Art

[0002] In recent years, air drilling technology has been promoted and applied in 793 deep and ultra-deep wells in Sichuan, Chongqing, Tarim, Songliao Basin and other areas, with a cumulative footage of 652,000 meters. It has played an important role in improving mechanical drilling speed, discovering and protecting reservoirs, and controlling malignant well leakage. The air hammer is the most commonly used downhole power drill in the air drilling process. The air drilling of the air hammer relies on high-frequency impact and rotation to break the rock. The bottom hole rock is broken under the combined action of drilling pressure, impact force and rotational shear force. However, air hammer air drilling has limitations in formation applicability and is not applicable in wet formations and formations prone to collapse. There is still much room for speed increase.

[0003] At present, in addition to air hammers used for air drilling, conventional PDC drill bits used in conjunction with air screw drilling have certain advantages over air hammers in terms of machine speed performance. However, conventional PDC drill bits still have significant shortcomings in drill bit service life. PDC drill bits used in conjunction with air screws require a completely new structural design.

[0004] Currently, conventional PDC drill bits, which are designed similarly to those used in mud drilling, are mostly used in conjunction with air screws. The actual drilling performance of conventional PDC drill bits in conjunction with air screws shows slight wear on the inner cone and nose cutting teeth of the drill bit, but severe wear on the outer shoulder cutting teeth. Analysis shows that the high drilling speed of the air screw leads to excessively high linear speeds of the outer shoulder cutting teeth. At the same time, due to the poor thermal conductivity of air and the poor cooling effect, the cutting teeth overheat and develop thermal cracks, which accelerate the wear and failure of the cutting teeth and subsequently grind to the drill blade body, resulting in annular grooves. Conventional PDC drill bits used for mud drilling are not suitable for use with air screw drilling, and the drill bit requires a new design.

[0005] Currently, there are PDC drill bits designed for air drilling. One is a PDC drill bit for downhole air drilling with authorization announcement number CN 111971447 B, and the other is a multi-material composite cutting drill bit for air screw drilling with authorization announcement number CN 116241186B. These two designs have roughly the same rock-breaking mechanism as conventional PDC drill bits and have no obvious advantages in flow channel design. It is expected that if used for air drilling, their performance will not be much different from that of conventional PDC drill bits. Therefore, PDC drill bits for air screw drilling need to be completely redesigned in terms of the rock-breaking mechanism of the cutting teeth and the flow channel design. Summary of the Invention

[0006] The purpose of the present invention is to provide a PDC drill bit for use with an air screw, so as to solve the problem in the prior art that the PDC drill bits currently used with air screw drilling are not optimized for the air screw, resulting in the PDC drill bits being prone to thermal cracks due to high temperatures during actual use, thereby accelerating the wear of the drill bit.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] The PDC drill bit is a very powerful drill that can drill holes in the drill bit, but it is not as powerful as the PDC drill bit itself, so the bit is more portable and can be used for drilling holes in small pieces. The PDC drill bit is very powerful, so it is very durable and can withstand high temperatures, which makes it very durable. It is a very powerful drill that can drill holes in small pieces, so it is very durable and can withstand high temperatures, which makes it very durable. The front end of the head body is connected to form an air outlet; the rear end of the drill body is provided with a mounting groove, in which an air flow distribution block is fixedly installed, and the rear end of the air flow distribution block is provided with a first rotating hole, in which a rotating tube is rotatably arranged, and the hole wall surrounding the first rotating hole is provided with air guide holes connected to a plurality of air outlet holes in a one-to-one correspondence, and a first through hole and a plurality of second through holes are provided on the tube wall surrounding the rotating tube. The aperture of the first through hole is larger than the aperture of the second through hole, and the rear end of the air flow distribution block is provided with a pneumatic rotating component for driving the rotating tube to rotate in the first rotating hole.

[0009] A core fixed water hole is provided at the center of the front end of the drill body; the pneumatic rotating assembly includes a fixed block, which is fixedly connected to the cavity wall of the mounting groove, and a rotating cavity is provided in the fixed block. The front and rear ends of the fixed block are aligned with second rotating holes connected to the rotating cavity, and the rear end of the rotating tube passes through the two second rotating holes in sequence and is placed on the rear side of the fixed block, and the rotating tube is rotatably connected to the two second rotating holes; the outer wall of the rotating tube is provided with a mounting ring in the rotating cavity, and a number of fan blades are arranged at intervals around the outer wall of the mounting ring; air inlet holes and exhaust holes aligned with the surface of the fan blades are arranged at intervals on the cavity wall of the rotating cavity, and an air inlet pipe connected to the air inlet hole is provided at the rear end of the fixed block; the front end of the air flow distribution block is provided with a central air hole connected to the core fixed water hole, and the exhaust hole is connected to the central air hole.

[0010] An insertion slot is provided at the rear end of the air flow distribution block, the bottom of the insertion slot is connected to the central air hole through a connecting hole, and an insertion tube connected to the exhaust hole is provided at the front end of the fixed block, and the insertion tube is connected to the connecting hole in the insertion slot.

[0011] A further technical solution is that the front auxiliary blade wing and the rear auxiliary blade wing are extended to the side of the drill body, and the main blade wing, the front auxiliary blade wing and the rear auxiliary blade wing are all protruded with diameter-protecting polycrystalline near the drill joint.

[0012] A further technical solution is that main cutting plane teeth are distributed on the main blade, front impact cone teeth are distributed on the front auxiliary blade, rear limiting cone teeth are distributed on the rear auxiliary blade, and replaceable nozzles are installed in the air outlet.

[0013] A further technical solution is that the height of the front row of impact cone-point teeth protruding from the surface of the drill bit body is consistent with the height of the main cutting plane teeth protruding from the surface of the drill bit body, and the height of the rear row of limiting cone-point teeth protruding from the surface of the drill bit body is lower than the height of the main cutting plane teeth protruding from the surface of the drill bit body.

[0014] A further technical solution is that the height of the rear-row limiting tapered teeth protruding from the surface of the drill body is lower than the height of the main cutting plane teeth protruding from the surface of the drill body and is controlled between 0.4-2 mm.

[0015] A further technical solution is that the cross-sectional area of ​​the main channel is 1.5-3 times the cross-sectional area of ​​the rear auxiliary blade channel, and the cross-sectional area of ​​the rear auxiliary blade channel is the same as the cross-sectional area of ​​the front auxiliary blade channel.

[0016] A further technical solution is that the width of the main channel is 12.7 mm and the depth is 20 mm, and the width of the rear auxiliary blade channel is 8 mm and the depth is 8 mm.

[0017] A further technical solution is that a core fixed water hole is provided at the center of the front end of the drill body, and a core impact spherical tooth is provided around the core fixed water hole at the front end of the drill body; the air outlet is connected to the core fixed water hole in the drill body.

[0018] A further technical solution is that the diameter of the fixed water hole in the center is 12.7 mm, and the spray angle of the replaceable nozzle is 25° with the axis of the drill body.

[0019] A further technical solution is that six main blades are arranged at intervals along the circumference of the drill body.

[0020] Compared with the existing technology, the present invention has the following beneficial effects: 1. The present invention adopts a multi-flow channel design. Through the design of the main channel, the rear auxiliary blade flow channel and the front auxiliary blade flow channel, cooling air flows through both sides of the main blade, the front auxiliary blade and the rear auxiliary blade during the drilling process, removing heat, thereby improving the cooling effect and chip removal effect. By placing the front auxiliary blade and the rear auxiliary blade on both sides of the main blade, they can assist the main blade in drilling and protect the main blade during drilling, thereby increasing the overall service life of the main blade and the drill bit body. 2. The present invention is based on the cooperation between the first through hole and the second through hole on the rotating tube. When the rotating tube rotates, the first through hole can pass through a plurality of air guide holes in sequence. In this way, by virtue of the aperture of the first through hole being larger than the aperture of the second through hole, the air flux entering the air guide hole through the first through hole can be greater than the air flux entering the air guide hole through the second through hole. In this way, when the air hole is connected with the first through hole through the air guide hole, the air flow volume of the air hole can be suddenly increased, forming a pulsed air discharge effect, thereby forming a high-speed and high-pressure airflow to the corresponding main channel, rear auxiliary blade flow channel and front auxiliary blade flow channel. It can prevent debris from accumulating in the main channel, the rear auxiliary blade channel and the front auxiliary blade channel; 3. Conventional air drills use the same airflow to cool and remove chips in the channel between each blade. Although this can achieve a uniform and stable effect, it is difficult to effectively clear or quickly unclog the blockage when a channel is suddenly blocked, which can easily lead to increased wear of the drill bit. The present invention can periodically perform differentiated airflow impacts on all channel through the differentiated aperture settings of the first through hole and the second through hole, so that the blocked debris can be unclogged due to the impact of the large airflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is an overall schematic diagram of a PDC drill bit used in conjunction with an air screw according to the present invention.

[0022] Figure 2 This is a schematic diagram of the main blade, front auxiliary blade and rear auxiliary blade of a PDC drill bit used in conjunction with an air screw according to the present invention.

[0023] Figure 3 This is a schematic diagram of multiple flow channels of a PDC drill bit used in conjunction with an air screw according to the present invention.

[0024] Figure 4 The figure is a side cross-sectional schematic diagram of a PDC drill bit used in conjunction with an air screw according to the present invention.

[0025] Figure 5 Schematic diagram of the air flow distribution block and fixed block of a PDC drill bit used with an air screw according to the present invention Figure 1 .

[0026] Figure 6Schematic diagram of the air flow distribution block and fixed block of a PDC drill bit used with an air screw according to the present invention Figure 2 .

[0027] Figure 7 This is a schematic cross-sectional view of a fixed block of a PDC drill bit used in conjunction with an air screw according to the present invention.

[0028] Figure 8 This is a partial cross-sectional schematic diagram of a rotating tube and a first rotating hole of a PDC drill bit used in conjunction with an air screw according to the present invention.

[0029] Icons: 1-front row impact cone-point teeth, 2-main cutting plane teeth, 3-rear row limiting cone-point teeth, 4-center impact spherical teeth, 5-replaceable nozzle, 6-center fixed water hole, 7-front auxiliary blade flow channel, 8-main channel, 9-rear auxiliary blade flow channel, 10-drill body, 11-diameter-maintaining polycrystalline, 12-drill joint, 13-front auxiliary blade, 14-main blade, 15-rear auxiliary blade, 16-mounting slot, 17-air flow distribution block, 18-first rotating hole, 19-rotating tube, 20-air guide hole, 21-first through hole, 22-second through hole, 23-fixed block, 24-rotating cavity, 25-second rotating hole, 26-mounting ring, 27-fan blade, 28-air inlet hole, 29-exhaust hole, 30-air inlet pipe, 31-center air hole, 32-insertion slot, 33-connecting hole, 34-insertion tube. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] Figures 1 to 8 Shown is an embodiment of the present invention.

[0032] Example 1:

[0033] A PDC drill bit for use with an air screw comprises a drill bit body 10 and a drill head 12 disposed at the rear end of the drill bit body 10. The drill bit body 10 is provided with main blades 14 along the direction from the front end to the sidewall. Several main blades 14 are spaced apart along the circumference of the drill bit body 10. A front auxiliary blade 13 and a rear auxiliary blade 15 are provided on opposite sides of each main blade 14. A main flow channel 8 and a rear auxiliary blade flow channel 9 are provided between the front auxiliary blade 13 and the rear auxiliary blade 15 and the main blade 14, respectively. A front auxiliary blade flow channel 7 is provided between adjacent front auxiliary blades 13 and rear auxiliary blades 15. The main flow channel 8, the rear auxiliary blade flow channel 9, and the front auxiliary blade flow channel 7 are connected at the front end of the drill bit body 10 to form an air outlet. A replaceable nozzle 5 is installed in the air outlet. A mounting slot 16 is provided at the rear end of the drill bit body 10, with the notch of the mounting slot 16 located at the rear end of the drill head 12. An airflow distribution block 17 is fixedly mounted within the mounting slot 16. A first rotating hole 18 is provided at the rear end of the airflow distribution block 17. A rotating tube 19 is rotatably mounted within the first rotating hole 18. Air guide holes 20 are provided on the wall surrounding the first rotating hole 18, each corresponding to a plurality of air outlet holes. A first through hole 21 and a plurality of second through holes 22 are provided on the wall surrounding the rotating tube 19. The diameter of the first through hole 21 is larger than that of the second through holes 22. A pneumatic rotating assembly for driving the rotating tube 19 to rotate within the first rotating hole 18 is mounted at the rear end of the airflow distribution block 17. The notch of the mounting slot 16 is located at the rear end of the drill bit joint 12. The present invention employs a multi-channel design. Through the design of the main channel 8, the rear auxiliary blade channel 9, and the front auxiliary blade channel 7, cooling air flows through both sides of the main blade 14, the front auxiliary blade 13, and the rear auxiliary blade 15 during drilling, removing heat and thereby improving cooling and chip removal. By placing the front auxiliary blade wing 13 and the rear auxiliary blade wing 15 on both sides of the main blade wing 14 respectively, the main blade wing 14 can be assisted in drilling during the drilling process and play a protective role for the main blade wing 14, thereby improving the overall service life of the main blade wing 14 and the drill bit body 10.

[0034] A core fixed water eye 6 is provided at the center of the front end of the drill body 10; the pneumatic rotating assembly includes a fixed block 23, which is fixedly connected to the cavity wall of the mounting groove 16, and a rotating cavity 24 is provided in the fixed block 23. The front and rear ends of the fixed block 23 are aligned with second rotating holes 25 connected to the rotating cavity 24. The rear end of the rotating tube 19 passes through the two second rotating holes 25 in sequence and is placed on the rear side of the fixed block 23, and the rotating tube 19 is rotatably connected to the two second rotating holes 25; the outer wall of the rotating tube 19 is provided with a mounting ring 26 in the rotating cavity 24, and a plurality of fan blades 27 are arranged at intervals around the outer wall of the mounting ring 26; air inlet holes 28 and exhaust holes 29 aligned with the surfaces of the fan blades 27 are arranged at intervals on the cavity wall of the rotating cavity 24, and the rear end of the fixed block 23 is provided with an air inlet pipe 30 connected to the air inlet hole 28; the front end of the air flow distribution block 17 is provided with a central air hole 31 connected to the core fixed water eye 6, and the exhaust hole 29 is connected to the central air hole 31. When the air from the air screw enters the drill bit position from the rod body, it enters the rotating tube 19 and the air inlet pipe 30 through the mounting groove 16. The diameter of the air inlet pipe 30 is the same as the diameter of the rotating tube 19, so that most of the airflow will enter the rotating tube 19 and a small part of the airflow will enter the air inlet pipe 30. After the air enters the rotating chamber 24 through the air inlet pipe 30, it will be blown to the surface of the fan blade 27 through the air inlet hole 28, thereby driving the fan blade 27 to rotate. The fan blade 27 drives the mounting ring 26 and the rotating tube 19 to rotate together, and after driving the fan blade 27 to rotate, the air will be discharged through the exhaust hole 29, and finally enter the central air hole 31 and the core fixed water hole 6 in turn to be discharged, cooling the front end of the drill bit body 10 and removing chips. When the rotating tube 19 rotates, it will connect the first through hole 21 with different air guide holes 20, so that all air holes have a large airflow discharged periodically. As shown Figure 8 As shown, the aperture of the first through hole 21 is larger than that of the air guide hole 20, and the aperture of the second through hole 22 gradually increases from the inside to the outside, with the aperture at the outer end matching the aperture of the air guide hole 20 and the aperture at the inner end being smaller than that of the outer end. This ensures that the gas flux of each second through hole 22 is smaller than that of the first through hole 21, and the spacing between the aperture edges of two adjacent air guide holes 20 is generally around 3-5 mm. This prevents excessive blocking of the first through hole 21 or the second through hole 22 by the hole wall between the two adjacent air guide holes 20 when the rotating tube 19 rotates. A positioning groove is provided at the bottom of the installation groove 16 where it connects to the air outlet, and a positioning bump is formed at the front end of the air flow distribution block 17 where it connects to the air guide hole 20. This allows for quick installation of the gas distribution block while connecting the air guide hole 20 and the air outlet. A limit ring is threadedly connected at a position where the mounting groove 16 fits the rear end of the fixing block 23 to prevent the fixing block 23 and the airflow distribution block 17 from falling out of the mounting groove 16 .

[0035] The rear end of the airflow distribution block 17 is provided with an insertion slot 32. The bottom of the insertion slot 32 is connected to the central air hole 31 through a connecting hole 33. The front end of the fixed block 23 is provided with an insertion tube 34 connected to the exhaust hole 29. The insertion tube 34 is connected to the connecting hole 33 within the insertion slot 32. The provision of the insertion slot 32 and the insertion tube 34 ensures accurate communication between the exhaust hole 29 and the connecting hole 33.

[0036] The front auxiliary blade wing 13 and the rear auxiliary blade wing 15 are extended to the side of the drill body 10, and the main blade wing 14, the front auxiliary blade wing 13 and the rear auxiliary blade wing 15 are all protruded with a gauge-maintaining polycrystalline 11 near the drill joint 12.

[0037] The main cutting plane teeth 2 are distributed on the main blade wing 14 , the front row impact cone-point teeth 1 are distributed on the front auxiliary blade wing 13 , and the rear row limiting cone-point teeth 3 are distributed on the rear auxiliary blade wing 15 .

[0038] The front row of impact cone teeth 1 protrude from the drill body 10 at the same height as the main cutting face teeth 2. The rear row of stop cone teeth 3 protrude from the drill body 10 at a lower height than the main cutting face teeth 2. The main cutting face teeth 2 utilize PDC composite inserts, which enhance the overall aggressiveness of the drill body 10 and improve machine speed performance. Furthermore, the front row of impact cone teeth 1 and the rear row of stop cone teeth 3 protect the main cutting face teeth 2, preventing premature damage and extending the drill bit's service life when used with an air screw. The main cutting plane teeth 2 are used as the main rock-breaking cutting teeth. The front row of impact cone-point teeth 1 have the same cutting edge as the main cutting plane teeth 2, and have an impact and destruction effect on the formation, assisting the main cutting plane teeth 2 in breaking the rock. The cutting edge of the rear row of limiting cone-point teeth 3 maintains a certain height difference with the main cutting teeth (DOC-depth of cut can be adjusted between 0.4-2mm according to the drillability of the formation), controlling the depth of the main cutting plane teeth 2 into the formation, and avoiding the main cutting plane teeth 2 from being damaged in advance due to instantaneous excessive force. The front row of impact cone-point teeth 1 and the rear row of limiting cone-point teeth 3 cooperate with the main cutting plane teeth 2 to form a new rock-breaking mechanism, thereby improving the adaptability of the drill bit body 10 to the bottom layer, better adapting to the power output of the air screw, improving the adaptability of the drill bit and the air screw, and thus improving the mechanical penetration rate and service life of the drill bit.

[0039] The cross-sectional area of ​​the main channel 8 is 1.5-3 times that of the rear auxiliary blade channel 9, which is the same as the front auxiliary blade channel 7. This rational distribution of air kinetic energy ensures that the main cutting plane teeth 2, the front impact cone teeth 1, and the rear limit cone teeth 3 on the main blade 14, front auxiliary blade 13, and rear auxiliary blade 15 have consistent service lives, thereby improving their overall lifespan.

[0040] A central fixed water hole 6 is located at the front end of the drill bit body 10. A core impact ball tooth 4 is positioned around the central fixed water hole 6. An air outlet is located within the drill bit body 10 and communicates with the central fixed water hole 6. The air output from the central fixed water hole 6 is primarily responsible for cooling the core impact ball tooth 4 and removing rock chips.

[0041] Six main blades 14 are spaced apart along the circumference of the drill bit body 10. This invention primarily incorporates the unique characteristics of air drilling and is based on the output characteristics of the air screw. Compared to previous designs, this invention incorporates new design elements in the rock-breaking mechanism of the cutters and the distribution of air kinetic energy (flow path design), enabling the drill bit to achieve superior speed and footage performance when combined with the air screw. Key features of this invention lie in the rock-breaking tooth arrangement of the blades—a main blade 14, a front auxiliary blade 13, and a rear auxiliary blade 15—and the flow path design that aligns with these blade arrangements. The shallow flow path design maximizes the transfer of air kinetic energy, improving cooling and chip removal efficiency. The multi-flow path design ensures effective cooling of the front row of impact cone tips 1 and the rear row of stop cone tips 3 on the front and rear auxiliary blades 13, 15, extending the overall service life of the drill bit. These two key technical features complement each other and are essential to maximize drill bit speed and footage performance.

[0042] Example 2:

[0043] The embodiment described below with reference to the accompanying drawings is specifically applied to air drilling in the 215.9 mm well section of the Dongfeng block in Ziyang.

[0044] like Figure 1 As shown, the present invention is a PDC drill bit for use with an air screw, comprising a drill bit body 10, six main blades 14 on the drill bit body, and two auxiliary blades (front auxiliary blade 13 and rear auxiliary blade 15) respectively in front and behind each main blade. The main blades 14 are provided with main cutting plane teeth 2, the front auxiliary blades 13 are provided with front row impact cone-point teeth 1, and the rear auxiliary blades 15 are provided with rear row limit cone-point teeth 3. The core of the drill bit body is provided with core impact spherical teeth 4, the drill bit gauge is provided with heat-stable polycrystalline wear-resistant joints, the core of the drill bit body is provided with a core fixed water hole 6, the drill bit body is provided with six replaceable nozzles 5, and the drill bit body is connected to the air screw via a drill bit joint 12.

[0045] Each front auxiliary blade wing 13 is provided with a front row of impact cone-point teeth 1, and its cutting edge is the same as that of the main cutting plane teeth 2 of the corresponding main blade wing 14;

[0046] Each rear auxiliary blade has a rear row of limiting tapered teeth 3, the cutting edge of which is 1 mm lower than the cutting edge of the main cutting plane teeth 2 of the corresponding main blade 14;

[0047] The width of the main channel 8 is designed to be 12.7 mm and the depth is designed to be 20 mm;

[0048] The width of the front and rear auxiliary blade wing flow channels is designed to be 8mm, and the depth is designed to be 8mm;

[0049] The blade crown adopts a short crown design, and the main blade 14 teeth have a medium tooth density.

[0050] The diameter of the central fixed water hole 6 is designed to be 12.7 mm, and the replaceable nozzle 5 adopts the MZ16 nozzle (the minimum through-hole inner diameter is 12.7 mm);

[0051] The main cutting plane tooth 2 adopts a plane composite piece with comprehensive performance and strong impact resistance;

[0052] Through fluid mechanics analysis, the optimized radial spray angle of the replaceable nozzle 5 is 25°, and the center spray angle of the nozzle blade is -3°;

[0053] The drill bit gauge is covered with a 10mm diameter heat-stable polycrystalline wear-resistant section;

[0054] Furthermore, professional optimization software is used to optimize the force on the cutting teeth, so that the axial and tangential forces on each tooth are balanced, and the overall unbalanced force of the drill bit is reduced to 0.8% (standard value 3%).

[0055] The inventors produced the drill bit according to the above technical solution and used it on site.

[0056] Although the present invention has been described herein with reference to a number of illustrative embodiments thereof, it will be understood that numerous other modifications and implementations may be devised by those skilled in the art that fall within the scope and spirit of the principles disclosed herein. More specifically, within the scope of the present disclosure, the drawings, and the claims, numerous variations and modifications may be made to the components and / or layout of the subject combination arrangement. In addition to variations and modifications to the components and / or layout, other uses will also be apparent to those skilled in the art.

Claims

1. A PDC drill bit for use with an air screw, comprising a drill bit body (10), characterized in that: The drill body (10) is provided with a main blade (14) along the direction from the front end to the side wall. A plurality of main blades (14) are arranged at intervals along the circumference of the drill body (10). A front auxiliary blade (13) and a rear auxiliary blade (15) are respectively provided on opposite sides of each main blade (14). A main flow channel (8) and a rear auxiliary blade flow channel (9) are respectively provided between the front auxiliary blade (13) and the rear auxiliary blade (15) and the main blade (14). A front auxiliary blade flow channel (7) is provided between two adjacent front auxiliary blades (13) and the rear auxiliary blade (15). The main flow channel (8), the rear auxiliary blade flow channel (9) and the front auxiliary blade flow channel (7) are respectively provided on the drill body (10). ) is connected to form an air outlet; the rear end of the drill body (10) is provided with a mounting groove (16), an air flow distribution block (17) is fixedly installed in the mounting groove (16), the rear end of the air flow distribution block (17) is provided with a first rotating hole (18), a rotating tube (19) is rotatably provided in the first rotating hole (18), and an air guide hole (20) is provided around the hole wall of the first rotating hole (18) and is connected to a plurality of air outlet holes in a one-to-one correspondence. A first through hole (21) and a plurality of second through holes (22) are provided on the tube wall around the rotating tube (19), the aperture of the first through hole (21) is larger than the aperture of the second through hole (22), and the air flow The rear end of the distribution block (17) is installed with a pneumatic rotating assembly for driving the rotating tube (19) to rotate in the first rotating hole (18); the center of the front end of the drill body (10) is provided with a core fixed water hole (6); the pneumatic rotating assembly includes a fixed block (23), the fixed block (23) is fixedly connected to the cavity wall of the mounting groove (16), a rotating cavity (24) is provided in the fixed block (23), and the front and rear ends of the fixed block (23) are aligned with the second rotating holes (25) connected to the rotating cavity (24), the rear end of the rotating tube (19) passes through the two second rotating holes (25) in sequence, and is placed on the rear side of the fixed block (23), and the rotating tube ( 19) is rotatably connected to the two second rotating holes (25); the outer wall of the rotating tube (19) is provided with a mounting ring (26) in the rotating cavity (24), and a plurality of fan blades (27) are arranged at intervals around the outer wall of the mounting ring (26); the cavity wall of the rotating cavity (24) is provided with air inlet holes (28) and air outlet holes (29) aligned with the surfaces of the fan blades (27) at intervals, and the rear end of the fixed block (23) is provided with an air inlet pipe (30) connected to the air inlet hole (28); the front end of the air flow distribution block (17) is provided with a central air hole (31) connected to the core fixed water hole (6), and the air outlet hole (29) is connected to the central air hole (31).

2. A PDC drill bit for use with an air screw according to claim 1, characterized in that: The rear end of the air flow distribution block (17) is provided with an insertion groove (32), the bottom of the insertion groove (32) is connected to the central air hole (31) through a connecting hole (33), and the front end of the fixed block (23) is provided with an insertion tube (34) connected to the exhaust hole (29), and the insertion tube (34) is connected to the connecting hole (33) in the insertion groove (32).

3. The PDC drill bit used in conjunction with an air screw according to claim 1, characterized in that: The front auxiliary blade wing (13) and the rear auxiliary blade wing (15) are both extended to the side of the drill body (10), and the main blade wing (14), the front auxiliary blade wing (13) and the rear auxiliary blade wing (15) are all protruded with a diameter-protecting polycrystalline (11) at a position close to the drill joint (12).

4. The PDC drill bit used in conjunction with an air screw according to claim 1, characterized in that: The main blade (14) is provided with main cutting plane teeth (2), the front auxiliary blade (13) is provided with front row impact cone-point teeth (1), and the rear auxiliary blade (15) is provided with rear row limiting cone-point teeth (3); the front end of the drill body (10) is provided with core impact spherical teeth (4) around the core fixed water hole (6); and a replaceable nozzle (5) is installed in the air outlet.

5. The PDC drill bit used in conjunction with an air screw according to claim 4, characterized in that: The height of the front row impact cone-point teeth (1) protruding from the surface of the drill bit body (10) is consistent with the height of the main cutting plane teeth (2) protruding from the surface of the drill bit body (10), and the height of the rear row limiting cone-point teeth (3) protruding from the surface of the drill bit body (10) is lower than the height of the main cutting plane teeth (2) protruding from the surface of the drill bit body (10).

6. The PDC drill bit used in conjunction with an air screw according to claim 5, characterized in that: The height of the rear-row limiting cone-point teeth (3) protruding from the surface of the drill bit body (10) is lower than the height of the main cutting plane teeth (2) protruding from the surface of the drill bit body (10), and is controlled between 0.4 and 2 mm.

7. The PDC drill bit used in conjunction with an air screw according to claim 6, characterized in that: The cross-sectional area of ​​the main channel (8) is 1.5-3 times the cross-sectional area of ​​the rear auxiliary blade wing channel (9), and the cross-sectional area of ​​the rear auxiliary blade wing channel (9) is the same as the cross-sectional area of ​​the front auxiliary blade wing channel (7); the width of the main channel (8) is 12.7 mm and the depth is 20 mm, and the width of the rear auxiliary blade wing channel (9) is 8 mm and the depth is 8 mm.

8. The PDC drill bit used in conjunction with an air screw according to claim 7, characterized in that: The diameter of the central fixed water hole (6) is 12.7 mm, and the jetting angle of the replaceable nozzle (5) is 25° with the axis of the drill body (10); six main blades (14) are arranged at intervals along the circumference of the drill body (10).

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