An adjustable adaptive rolling composite drill bit

Abstract

This invention discloses an adjustable adaptive rolling-cutting composite drill bit, belonging to the field of oil and gas drilling equipment. It includes a drill bit body equipped with multiple rollers, and a cutter blade assembly at the center of the drill bit body that can extend and retract axially but cannot rotate relative to it. The cutter blade assembly is equipped with a diamond composite blade for rock breaking. A worm gear mechanism is installed inside the drill bit body to adjust the axial extension and retraction pressure of the cutter blade assembly, and an elastic element is installed between the worm gear mechanism and the cutter blade assembly. This invention can set or adjust the rock-breaking pressure of the cutter blade assembly on the rock according to the lithology of the drilled formation and drilling parameters. Especially when the formation is hard, by using a rolling-cutting alternating rock-breaking method, the overall rock-breaking efficiency and service life of the composite drill bit are significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas drilling equipment, and more specifically, relates to an adjustable adaptive rolling composite drill bit. Background Technology

[0002] Currently, the main drilling methods used in oil and gas drilling are tricone bits and diamond cone (PDC) bits. PDC bits break rock through scraping, and while they offer high drilling speeds, they are not suitable for hard formations, interbedded formations with alternating hard and soft layers, or gravel formations. Tricone bits, on the other hand, break rock through impact crushing and slip scraping, making them suitable for high-hardness and complex formations, but they have lower rock-breaking efficiency and slower drilling speeds. Based on the different characteristics of these two types of bits, a new type of drill bit—the hybrid drill bit—has been developed.

[0003] For example, application number 200880016630.0 discloses a hybrid drill bit integrating a roller cone drill bit and a PDC drill bit. In the mixed area of ​​the roller cone (with carbide cutting teeth embedded on it) and the cutter blade (with PDC cutting teeth embedded on it), multiple rock-breaking mechanisms can be synergistically utilized. The roller cone cutting teeth form discontinuous pits through impact crushing, while the PDC cutting teeth connect the pre-crushed pits through cutting action to form a complete crushing ring. Simultaneously, the roller cone cutting teeth limit the excessive infeed of the PDC cutting teeth, thereby reducing the overload probability of the PDC cutting teeth. The diversity of cutting mechanisms in the hybrid drill bit increases its adaptability to formations. It integrates the advantages of PDC and roller cone drill bits, and has shown good performance in soft-to-medium hard formations, formations prone to mud-coating, hard plastic formations, and some soft-hard mixed formations. However, the roller cone structure and PDC cutter blade of this hybrid drill bit are a rigid whole. During the rock breaking process, the impact vibration generated by the axial impact of the roller cone cutting teeth on the rock breaking will be directly transmitted to the PDC cutting teeth, causing the PDC teeth to fail prematurely and greatly reducing the service life of the hybrid drill bit.

[0004] To overcome this technical problem, the adaptive hybrid drill bit disclosed in application number 2012100154208 simultaneously features both roller cones and cutter wings. The roller cones are mounted on the toothed surfaces of the drill bit body, and the roller cones and cutter wings are evenly distributed and staggered. Simultaneously, a movable cutter wing body is installed within the drill bit body, capable of axial extension and retraction only within a limited range. An elastic element providing axial thrust to the movable cutter wing body is also provided between the movable cutter wing body and the drill bit body. The cutter wing body is located at the front end of the movable cutter wing body, while the rear end of the movable cutter wing body has a pressure-bearing surface to withstand mud pressure. This technical solution can control the relative position of the roller cones and cutter wings through drilling pressure, adjusting the distribution of rock-breaking volume between the roller cones and cutter wings, resulting in faster rock-breaking speed and wider applicability. However, during drilling, the roller cone and cutter blades require different rock-breaking pressures for different formations. In this technical solution, the elastic force of the elastic element can only be kept fixed, making it difficult for the drilling effect of the drill bit to adapt to changes in the formation. If the drilling requirements of different formations are to be met, the drill bit must be removed and disassembled to replace the elastic element, which is not only troublesome to operate, but will also seriously affect the efficiency of drilling operations. Summary of the Invention

[0005] The purpose of this invention is to provide an adjustable adaptive rolling-cutting composite drill bit that can set or adjust the rock-breaking pressure of the cutter blade assembly on the formation according to the lithology of the drilled formation and drilling parameters. Especially when encountering harder formations, the composite drill bit can significantly improve its overall rock-breaking efficiency and service life by using a combination of rolling and cutting to break the rock.

[0006] To achieve the objective of this invention, the technical solution adopted is as follows: an adjustable adaptive rolling composite drill bit, comprising a drill bit body with multiple rollers mounted thereon, a mounting hole at the center of the drill bit body, a cutter wing assembly that can move axially but cannot rotate inserted into the mounting hole, the cutter wing assembly having movable cutter wings arranged at intervals with the multiple rollers; a worm gear mechanism that can adjust the axial pushing force applied to the cutter wing assembly is installed inside the drill bit body, and an elastic element is installed between the worm gear mechanism and the cutter wing assembly.

[0007] Furthermore, it also includes a connecting body connected to the drill bit body, a worm gear mechanism installed inside the connecting body, and a connecting pipe installed inside the connecting body. The connecting pipe is rotatably fastened to the cutter blade assembly, and the drill bit body also has a stop corresponding to the connecting pipe.

[0008] Furthermore, the blade assembly also has a connector that is inserted into the mounting hole, the outer wall of the connector has a insertion groove, and one side wall of the insertion groove has a card interface; the connecting pipe also has a plug that is inserted into the insertion groove, and the plug has a card connector that can be inserted into the card interface.

[0009] Furthermore, there are multiple insertion slots, which are arranged at intervals along the circumference of the insertion joint.

[0010] Furthermore, the end of the connecting pipe near the plug is closed, and the sealed end of the connecting pipe and the plug have interconnected mud channels.

[0011] Furthermore, a rectangular surface is provided on the outer wall of the connecting pipe, and a locking bolt that mates with the rectangular surface is installed on the drill bit body.

[0012] Furthermore, the outer wall of the connecting pipe is a stepped shaft, the plug is located at the large-diameter end of the connecting pipe, and the elastic element and the pushing element are both sleeved on the small-diameter end of the plug.

[0013] Furthermore, the worm gear mechanism includes a threaded sleeve fitted on the connecting pipe, and a pusher that can move axially but cannot rotate is also fitted on the connecting pipe. The pusher abuts against the elastic element, and the threaded sleeve is threadedly engaged with the pusher. The worm gear mechanism also includes a drive structure for driving the threaded sleeve to rotate.

[0014] Furthermore, a guide pin is installed on the stepped surface of the inner hole of the connecting body, and an insertion hole is provided on the pushing component to slide with the guide pin.

[0015] Furthermore, a worm gear is fixed on the threaded sleeve, and the drive structure includes a worm that meshes with the worm gear, the worm being rotatably mounted on the connecting body.

[0016] Furthermore, the drill bit body has fixed blades arranged at intervals with the movable blades. A U-shaped groove is opened on the back of the fixed blades. The roller is installed in the U-shaped groove through the central shaft and rotates on the central shaft. The two ends of the central shaft are supported and fixed in the shaft holes on the wall of the U-shaped groove.

[0017] Furthermore, the outer surface of the fixed blade has a drainage groove that extends along the length of the drill bit body, with one end of the drainage groove extending toward the roller.

[0018] Furthermore, there are multiple movable blades and multiple fixed blades.

[0019] Furthermore, the outer surface of the movable blade is also provided with a mud flow channel groove.

[0020] Furthermore, there is a gap between the fixed cutter wing and the movable cutter wing, and multiple water holes are provided on the drill bit body, with the multiple water holes respectively distributed in the center of the movable cutter wing and in the mud flow channel groove of the movable cutter wing.

[0021] The beneficial effects of this invention are: When it is necessary to set or adjust the prepressure of the movable cutter blade according to different formation lithology and drilling parameters, the tightness of the elastic element can be set or adjusted by the worm gear mechanism in the drill bit body. This allows the drill bit roller and movable cutter blade to achieve a rock breaking process of rolling pressure followed by scraping under different drilling pressures, which greatly improves the drilling efficiency of the composite drill bit. Attached Figure Description

[0022] The accompanying drawings illustrate exemplary embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification.

[0023] Figure 1 This is a structural diagram of an adjustable adaptive rolling cut composite drill bit; Figure 2 This is a cross-sectional schematic diagram of an adjustable adaptive rolling composite drill bit; Figure 3 This is a top view of an adjustable adaptive rolling composite drill bit; Figure 4 This is a structural diagram of the drill bit body; Figure 5 This is a structural diagram of the blade wing assembly; Figure 6 This is a schematic diagram of the installation of elastic elements, pushers, and threaded sleeves.

[0024] The attached diagram shows the markings and corresponding component names: 1. Drill bit body; 2. Cutter blade assembly; 3. Locking bolt; 4. Connecting pipe; 5. Elastic element; 6. Pushing component; 7. Threaded sleeve; 8. Connecting body; 9. Worm gear. 11. Mounting hole; 12. Stop; 13. Fixed blade; 14. U-shaped groove; 15. Roller; 16. Drainage groove. 21. Connector; 22. Insertion slot; 23. Snap-fit ​​interface; 24. Movable cutter blade; 25. Mud flow channel; 26. Water eye. 41. Rectangular surface; 42. Plug-in connector; 43. Snap-fit ​​connector; 44. Mud channel; 61. Socket; 71. Worm gear; 81. Guide pin. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] like Figures 1 to 6 As shown, the present invention provides an adjustable adaptive rolling composite drill bit, comprising a drill bit body 1, on which a plurality of rotatable rollers 15 are mounted, the rollers 15 being spaced apart along the circumference of the drill bit body 1; simultaneously, the drill bit body 1 has a mounting hole 11 at its center, into which a cutter wing assembly 2 is inserted, the cutter wing assembly 2 being able to generate a certain displacement along its axial direction within the mounting hole 11, the cutter wing assembly 2 being non-rotatable within the mounting hole 11, and the cutter wing assembly 2 not detaching from the drill bit body 1 during use, but being able to be removed from the mounting hole 11 when replacement or disassembly is required. The cutter wing assembly 2 has a plurality of movable cutter wings 24, the movable cutter wings 24 also being spaced apart along the circumference of the drill bit body 1, and the movable cutter wings 24 and the plurality of rollers 15 being spaced apart, that is, each movable cutter wing 24 is located between two adjacent rollers 15, and each roller 15 is located between two adjacent movable cutter wings 24.

[0028] like Figure 2 , Figure 6 As shown, a worm gear mechanism and an elastic element 5 are installed inside the drill bit body 1. The elastic element is located between the worm gear mechanism and the cutter blade assembly 2. The direction of the elastic force of the elastic element 5 is consistent with the direction of movement of the cutter blade assembly 2, and the worm gear mechanism can adjust the extension and retraction of the elastic element 5, thereby adjusting the axial pushing force applied to the cutter blade assembly 2. The elastic element 5 can be a helical spring, a disc spring, high-strength rubber, etc., but a disc spring is preferred. Before use, the tension of the elastic element 5 can be adjusted through the worm gear mechanism. When the movable blade 24 in the blade assembly 2 is cutting and drilling into the formation, the priority of the roller 15 and the movable blade 24 can be changed according to the lithology of the formation. When the formation is hard, the roller 15 can be used first for rolling, and then the movable blade 24 can be used for scraping, which greatly reduces the damage of hard formation to the cutting teeth of the movable blade 24 and improves the service life of the drill bit. When the formation is soft, the movable blade 24 is used first for cutting, which maximizes the rock breaking advantage of the composite blade drill bit in medium and soft formations.

[0029] In this invention, through the design of the elastic element 5, when the formation resistance of the blade assembly 2 is lower than its preset pressure, the blade assembly 2 is pushed forward by the elastic force of the elastic element itself. At this time, the cutting teeth of the movable blade 24 are higher than the teeth of the roller 15, and the movable blade 24 plays the main role in cutting and breaking rocks, while the roller 15 plays the secondary role in rolling and breaking rocks. When the formation resistance of the blade assembly 2 is equal to the preset pressure, the elastic element 5 of the blade assembly 2 is further compressed, and the height of the cutting teeth of the movable blade 24 and the teeth of the roller 15 is basically the same. The cutting ability of the movable blade 24 is enhanced, and the roller 15 also participates in rolling and breaking rocks simultaneously. When the formation resistance of the blade assembly 2 is higher than the preset pressure, the teeth of the roller 15 will be higher than the composite plate on the movable blade 24. After the rock is broken by the roller 15 first, mainly by rolling, the cutting teeth on the movable blade 24 then cut the rolled formation, truly realizing the rock breaking process of rolling first and then cutting, and rolling and cutting compound alternation. It should be noted that the forward movement, high, and low here are all based on the drilling direction of the drill bit.

[0030] In this invention, a connecting body 8 is also connected to the drill bit body 1. The central axis of the connecting body 8 is on the same straight line as the central axis of the drill bit body 1. The end of the connecting body 8 away from the drill bit body 1 has a connecting thread, and the end of the connecting body 8 near the connecting body 8 is inserted into the drill bit body 1. The drill bit body 1 can move axially on the connecting body 8 but cannot rotate. After the drill bit body 1 is connected to the connecting body 8, the outer circular surface of the drill bit body 1 near the connecting body 8 is flush with the outer circular surface of the connecting body 8. The pusher 6 and the worm gear mechanism are both installed in the connecting body 8, and a connecting pipe 4 is also installed in the connecting body 8. The connecting pipe 4 is rotatably engaged with the cutter blade assembly 2, and the drill bit body 1 also has a stop 12 corresponding to the connecting pipe 4. After the connecting pipe 4 is connected to the cutter wing assembly 2, both the connecting pipe 4 and the cutter wing assembly 2 can only move along the axis of the drill body 1 and cannot rotate inside the drill body 1. At the same time, the connecting pipe 4 cooperates with the stop 12 on the drill body 1, so that the connecting pipe 4 cannot be detached from the drill body 1 after being connected to the cutter wing assembly 2. This ensures the stability of the cutter wing assembly 2 while making it easy to install and remove.

[0031] In this invention, such as Figure 3 , Figure 5As shown, the blade assembly 2 has a connector 21 that is inserted into the mounting hole 11. The connector 21 and the blade assembly 2 are an integral structure. The outer wall of the connector 21 has a insertion groove 22. The insertion groove 22 extends along the axis of the drill body 1. The connector 42 penetrates the end face of the connector 21 near the elastic element 5. The insertion groove 22 corresponds to the stop 12 on the drill body 1. The side wall of the insertion groove 22 also has a locking interface 23. The end of the connecting tube 4 extending towards the blade assembly 2 has a connector 42 corresponding to the insertion groove 22. The connector 42 also has a locking interface 43 corresponding to the locking interface 23. The connector 42 and the snap-fit ​​connector 43 are an integral structure, forming an L-shaped structure. During design, to ensure that the connector 42 can be inserted into the insertion slot 22, the width of the L-shaped structure formed by the connector 42 and the snap-fit ​​connector 43 matches the width of the insertion slot 22. After the L-shaped structure is inserted into the insertion slot 22, rotating the connecting pipe 4 causes the snap-fit ​​connector 43 to be inserted into the snap-fit ​​interface 23, thus connecting the connecting pipe 4 to the cutter wing assembly 2. To ensure that the cutter wing assembly 2 can move along the axial direction of the drill body 1, after the snap-fit ​​connector 43 is engaged in the snap-fit ​​interface 23, the snap-fit ​​connector 43 and the snap-fit ​​interface 23 have an axial gap consistent with the axial direction of the drill body 1.

[0032] In this invention, in order to ensure that the connector 21 corresponds to the stop 12 on the drill body 1 while designing the plug 42 and the snap connector 43, the snap connector 43 can be directly set on the end face of the connecting pipe 4, and the mounting hole 11 on the drill body 1 can be directly designed as a stepped hole. The stepped surface of the stepped hole is the stop 12 on the drill body 1. When the snap connector 43 is inserted into the snap connector 23, the end face of the connecting pipe 4 cooperates with the stop 12, which not only facilitates the connection between the connecting pipe 4 and the blade assembly 2, but also prevents the blade assembly 2 from falling off the drill body 1.

[0033] In this invention, in order to make the connection between the blade assembly 2 and the drill body 1 more stable, there can be multiple insertion slots 22 on the connector 21. The multiple insertion slots 22 are evenly spaced along the circumferential direction of the connector 21. At the same time, the number and position of the plugs 42 on the connecting pipe 4 correspond one-to-one with the number and position of the insertion slots 22.

[0034] To facilitate the design of the connector 42 on the connecting pipe 4, such as Figure 2 As shown, the end of the connecting pipe 4 near the connector 42 can also be made closed. In this case, the connector 42 is located on the closed end face of the connecting pipe 4. At the same time, in order to ensure that the mud can cool the cutting teeth of the drill bit, the closed end of the connecting pipe 4 and the connector 42 are also provided with mud channels 44 that are interconnected. After the mud enters the connecting pipe 4, it can be discharged from the drill bit through the mud channels 44, so that the mud can cool the cutting teeth of the drill bit during the drilling process.

[0035] To ensure that the cutter blade assembly 2 can move along the axis of the drill bit body 1, such as... Figure 2 As shown, the outer wall of the connecting pipe 4 also has a rectangular surface 41, and the drill body 1 is also equipped with a locking bolt 3 corresponding to the rectangular surface 41. By cooperating with the rectangular surface 41, the connecting pipe 4 is installed in the drill body 1. The tail of the locking bolt 3 is in clearance fit with the rectangular surface 41. At this time, the connecting pipe 4 and the drill body 1 are not directly locked and fixed, so that the connecting pipe 4 can move along the axial direction on the drill body 1. The connecting pipe 4 cannot rotate inside the drill body 1, so that the cutter wing assembly 2 can move along the axial direction of the drill body 1. This avoids the connecting pipe 4 from separating from the cutter wing assembly 2 due to the rotation of the connecting pipe 4 inside the drill body 1, and keeps the connection between the cutter wing assembly 2 and the connecting pipe 4 stable.

[0036] In this invention, to facilitate the installation of the elastic element 5, such as... Figure 2 , Figure 6 As shown, the outer wall of the connecting pipe 4 can be configured as a stepped shaft structure. In this case, the plug 42 is located on the large-diameter end face of the connecting pipe 4, and the elastic element 5 and the pusher 6 are both sleeved on the small-diameter end of the plug 42, so that one end of the elastic element 5 is pressed against the stepped surface on the outer wall of the connecting pipe 4, and the other end of the elastic element 5 is pressed against the pusher 6. This not only ensures the force applied by the elastic element 5 to the blade assembly 2, but also prevents the elastic element 5 from tilting, so that the force distribution on the elastic element 5 is more uniform when the pusher 6 moves, and the service life of the elastic element 5 is guaranteed.

[0037] To ensure the pushing of the pusher 6, such as Figure 2 , Figure 6As shown, the worm gear mechanism includes a threaded sleeve 7 fitted onto the connecting pipe 4, and a pusher 6 fitted onto the connecting pipe 4. The pusher 6 is in abutting state with the elastic element 5, and the inner diameter of the pusher 6 is in clearance fit with the outer diameter of the connecting pipe 4. The pusher 6 can move axially on the connecting pipe 4 but cannot rotate. Through the movement of the pusher 6, the pusher 6 can move closer to or further away from the cutter blade assembly 2 within the drill bit body 1. As the pusher 6 moves closer to or further away from the cutter blade assembly 2, the elastic element 5 is compressed or reset, thereby adjusting the preload of the elastic element and adjusting the axial pushing force applied to the cutter blade assembly 2. The pusher 6 is threadedly engaged with the threaded sleeve 7, and the pusher 6 is also slidably engaged with the connecting body 8, so that the pusher 6 can only move along the axial direction of the connecting body 8 and cannot rotate within the connecting body 8. At the same time, the worm gear mechanism also includes a drive structure (not shown in the figure) that drives the threaded sleeve 7 to rotate. The drive structure drives the threaded sleeve 7 to rotate, and through the threaded engagement between the threaded sleeve 7 and the pusher 6, and the sliding engagement between the pusher 6 and the connecting body 8, the pusher 6 can only move along the axial direction of the threaded sleeve 7 when the threaded sleeve 7 rotates, so that the elastic element 5 is compressed or reset, thereby adjusting the preload of the elastic element 5.

[0038] To prevent the drive structure from affecting the drill bit's drilling progress, the drive structure is preferentially installed inside the connecting body 8; simultaneously, to ensure the fit between the pusher 6 and the threaded sleeve 7, such as... Figure 2 As shown, the pusher 6 has a cap-like structure and a through hole for the connecting pipe 4 to pass through. The inner wall of the pusher 6 has an internal thread that mates with the threaded sleeve 7. Simultaneously, at least one guide pin is installed on the stepped surface of the inner hole of the connecting body 8, and the pusher also has a socket for the guide pin. During the design, the length of the guide pin must ensure that the guide pin remains inserted in the socket during the reciprocating motion of the pusher. When there are multiple guide pins, they are evenly spaced circumferentially along the central axis of the connecting body. In this case, the number and position of the sockets on the pusher correspond one-to-one with the number and position of the guide pins on the stepped surface of the inner hole of the connecting body. The cooperation between the guide pins and the sockets not only prevents the pusher from rotating on the connecting pipe but also effectively prevents the pusher from tilting during its reciprocating motion on the connecting pipe, thus ensuring that the central axis of the pusher always coincides with the central axis of the connecting pipe.

[0039] Without considering the difficulty of processing, in order to ensure that the pusher 6 can move axially but not rotate within the connecting body 8, a protrusion can be provided on the outer wall of the pusher, and a groove that slides and engages with the protrusion can be provided on the inner wall of the connecting body 8. The engagement of the groove and the protrusion can also effectively prevent the pusher from rotating within the connecting body.

[0040] In this invention, to ensure the driving structure drives the threaded sleeve 7, the end of the threaded sleeve 7 away from the elastic element 5 has a worm gear 71. The driving structure includes a worm 9 that meshes with the worm gear 71. The rotation of the worm 9 drives the worm gear 71 to rotate, thereby causing the threaded sleeve 7 to rotate. By driving the worm gear 71 on the threaded sleeve 7 to rotate through the driving structure, the threaded sleeve 7 is driven to rotate, causing the pusher 6 to move along its axial direction within the connecting body 8.

[0041] In this invention, the power source for the worm 9 in the drive structure can be either manual or an electric motor. When the worm 9 is manually driven to rotate, one end of the worm 9 passes through the connecting body 8 but does not extend beyond the outer surface of the connecting body 8. The worm 9 rotates and seals with the connecting body 8 while passing through it. The end of the worm 9 passing through the connecting body 8 has a groove corresponding to an internal hex wrench. In this case, the adjustment of the preload of the elastic element 5 needs to be completed before the drill bit is lowered into the well. When the worm 9 is driven to rotate by an electric motor (which is a reversible motor), both the worm 9 and the motor need to be installed inside the connecting body 8. In this case, the motor drives the worm 9 to rotate, which in turn drives the worm wheel 71 to rotate, causing the threaded sleeve 7 to rotate, thereby adjusting the preload of the elastic element 5. In this case, the adjustment of the preload of the elastic element 5 can be automatically adjusted as needed during the drilling process.

[0042] In this invention, in order to ensure the drilling progress of the drill bit, such as Figure 4 As shown, the drill bit body 1 also has fixed blades 13 spaced apart from the movable blades 24. Cutting teeth are installed on the cutting surfaces of both the fixed blades 13 and the movable blades 24, and both the diameter-maintaining sections of the fixed blades 13 and the movable blades 24 have diameter-maintaining teeth. A U-shaped groove 14 is formed on the back of the fixed blades 13. Shaft holes are formed on the two oppositely arranged groove walls within the U-shaped groove 14, and a central shaft is fixed in both shaft holes. Rollers 15 are rotatably mounted on the central shaft via bearings. This design ensures the cutting capability of the drill bit, and because the rollers 15 are mounted on the fixed blades 13, compared to using two separate support seats to rotate the rollers 15, the structural strength is greatly improved, significantly extending the service life of the drill bit. It should be noted that the back of the fixed blades 13 is the side of the fixed blades 13 opposite to the cutting surfaces of the movable blades 24.

[0043] To ensure the cooling of the roller 15 by the mud and the flow of mud during drilling, the outer surface of the fixed blade 13 is also provided with a drainage groove 16. One end of the drainage groove 16 extends to the diameter-maintaining section of the fixed blade 13 and passes through the end face of the diameter-maintaining section of the fixed blade 13. The other end of the drainage groove 16 extends towards the roller 15, so that the roller 15 can be fully cooled by the mud during the cutting process.

[0044] Furthermore, a mud flow channel 25 is also provided on the outer surface of the movable cutter wing 24. One end of the mud flow channel 25 penetrates the end face of the diameter-maintaining section of the movable cutter wing 24. At the same time, multiple water holes 26 are also provided on the cutter wing assembly 2. All the water holes 26 are connected to the mud channel 44 on the cutter wing assembly 2. Among the multiple water holes 26, some water holes 26 are located in the mud flow channel 25, some water holes 26 are located between the fixed cutter wing 13 and the movable cutter wing 24, and some water holes 26 are located in the center of the movable cutter wing 24. The mud used to cool the cutting teeth can be distributed as evenly as possible on the drill bit crown.

[0045] In this invention, to ensure the stability of the connection between the connecting pipe 4 and the blade assembly 2, after the connecting pipe 4 and the blade assembly 2 are connected, the connecting pipe 4 and the blade assembly 2 can be further fixed together by bolts; to prevent leakage of mud when it enters the mud channel 44 on the blade assembly 2 through the mud channel 44 on the connecting pipe 4, a sealing gasket or sealing ring can be installed between the end face of the closed end of the connecting pipe 4 and the end face of the connecting head 21; to prevent leakage of mud from the connection between the connecting body 88 and the drill bit body 1, a sealing ring is also embedded at the end of the connecting body 8 near the drill bit body 1, so that the connection between the connecting body 8 and the drill bit body 1 can maintain a sealed fit after the connecting body 8 and the drill bit body 1 are connected.

[0046] In this invention, the cutting teeth on the cutting surfaces of the fixed blade 13 and the movable blade 24 can be PDC teeth. Of course, other types and materials of cutting teeth can also be selected as needed. In this invention, when the roller 15 is installed, the axle of the roller 15 should be kept as far as possible from extending beyond the outer surface of the fixed blade 13. Meanwhile, in this invention, since the drill body 1 has a fixed blade 13, and the movable blade 24 is spaced apart from the fixed blade 13, the mounting hole 11 on the drill body 1 can be a straight hole to ensure the fit between the stop 12 on the drill body 1 and the end face of the connecting pipe 4. In this case, the stop 12 on the drill body 1 can be formed on the fixed blade 13. In this invention, the drill body 1 and the connecting body 8 are connected by threads.

[0047] In this invention, in order to prevent the slurry flowing through the connecting body 8 from entering the gap between the outer wall of the connecting pipe 4 and the inner wall of the connecting body 8 and affecting the elastic element 5, the pushing element 6, the threaded sleeve 7, etc., a sealing ring is installed at the end of the connecting pipe 4 away from the blade assembly 2, so that the end of the connecting pipe 4 away from the blade assembly 2 is sealed and fitted with the connecting body 8.

[0048] When assembling the drill bit, first insert the connector 21 on the cutter wing assembly 2 into the mounting hole 11 on the drill bit body 1. Then, insert the connecting pipe 4 into the drill bit body 1 and insert the plug 42 on the connecting pipe 4 into the insertion groove 22. Rotate the connecting pipe 4 so that the snap-fit ​​connector 43 on the plug 42 is inserted into the snap-fit ​​interface 23 on the groove wall of the insertion groove 22, so that the connecting pipe 4 is snapped into the cutter wing assembly 2. Continue to connect the connecting pipe 4 to the connector 21 on the cutter wing assembly 2 with screws. Install the locking bolt 3 on the drill bit body 1 and make the tail of the locking bolt 3 clearance fit with the rectangular surface 41. Next, put the elastic element 5, the pusher 6, and the threaded sleeve 7 on the connecting pipe 4 in sequence and make the threaded sleeve 7 threaded into the pusher 6. Next, put the connecting body 8 on and make the protrusion on the pusher 6 slide into the sliding groove 81 on the connecting body 8. Finally, put the sealing ring on the connecting body 8 and tighten the connecting body 8 to the drill bit body 1.

[0049] During use, when the stratum is hard and the roller 15 is used to cut the stratum, the elastic element 5 does not require a sufficiently large preload. In this case, the drive structure is activated, the drive structure reverses, the drive structure drives the threaded sleeve 7 to rotate in the opposite direction, the pusher 6 moves backward, the elastic element 5 extends, and the preload of the elastic element 5 decreases. When the stratum is soft and the cutting teeth on the movable blade 24 are used to cut, the elastic element 5 requires a sufficiently large preload. The drive structure rotates forward, the drive structure drives the threaded sleeve 7 to rotate in the forward direction, the pusher 6 moves forward, the elastic element 5 is compressed, and the preload of the elastic element 5 increases.

[0050] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. An adjustable adaptive rolling composite drill bit, characterized in that, The drill bit body (1) includes a drill bit body (1) with multiple rollers (15) installed. The drill bit body (1) has a mounting hole (11) at its center. An axially movable but non-rotatable cutter wing assembly (2) is inserted into the mounting hole (11). The cutter wing assembly (2) has movable cutter wings (24) spaced apart from the multiple rollers (15). The drill bit body (1) is equipped with a worm gear mechanism that can adjust the axial thrust applied to the cutter wing assembly (2). An elastic element (5) is installed between the worm gear mechanism and the cutter wing assembly (2). The drill bit body (1) also includes a connecting body (8) connected to the drill bit body (1). The worm gear mechanism is installed in the connecting body (8). A connecting pipe (4) is also installed in the connecting body (8). The connecting pipe (4) is rotatably fastened to the cutter wing assembly (2). The drill bit body (1) also has a stop (12) corresponding to the connecting pipe (4). A rectangular surface (41) is also provided on the outer wall of the drill bit body (1), and a locking bolt (3) that cooperates with the rectangular surface (41) is also installed on the drill bit body (1); the worm gear mechanism includes a threaded sleeve (7) sleeved on the connecting pipe (4), and a pusher (6) that can move axially but cannot rotate is also sleeved on the connecting pipe (4). The pusher (6) abuts against the elastic element (5), the threaded sleeve (7) and the pusher (6) are threadedly engaged, and the worm gear mechanism also includes a drive structure that drives the threaded sleeve (7) to rotate; a guide pin (81) is also installed on the stepped surface of the inner hole of the connecting body (8), and an insertion hole (61) that slides with the guide pin (81) is provided on the pusher (6); a worm gear (71) is also fixed on the threaded sleeve (7), and the drive structure includes a worm (9) that meshes with the worm gear (71). The worm (9) is rotatably installed on the connecting body (8).

2. The adjustable adaptive rolling composite drill bit according to claim 1, characterized in that, The blade assembly (2) also has a connector (21) that is inserted into the mounting hole (11). The connector (21) has a insertion groove (22) on its outer wall and a card interface (23) on one side of the groove wall. The connecting pipe (4) also has a plug (42) that is inserted into the insertion groove (22). The plug (42) has a card interface (43) that can be inserted into the card interface (23).

3. The adjustable adaptive rolling composite drill bit according to claim 2, characterized in that, There are multiple insertion slots (22), and the multiple insertion slots (22) are arranged at intervals along the circumferential surface of the connector (21).

4. The adjustable adaptive rolling composite drill bit according to claim 2, characterized in that, The end of the connecting pipe (4) near the plug (42) is closed, and the sealed end of the connecting pipe (4) and the plug (42) are provided with a mud channel (44) that communicates with each other.

5. The adjustable adaptive rolling composite drill bit according to claim 2, characterized in that, The outer wall of the connecting pipe (4) is a stepped shaft, the plug (42) is located at the large diameter end of the connecting pipe (4), and the elastic element (5) and the pusher (6) are both sleeved on the small diameter end of the plug (42).

6. The adjustable adaptive rolling composite drill bit according to claim 1, characterized in that, The drill bit body (1) has fixed blades (13) arranged at intervals with the movable blades (24). A U-shaped groove (14) is opened on the back of the fixed blades (13), and a roller (15) is rotatably installed in the U-shaped groove (14).

7. The adjustable adaptive rolling composite drill bit according to claim 6, characterized in that, The outer surface of the fixed blade (13) has a drainage groove (16), which extends along the length of the drill body (1) and one end of the drainage groove (16) extends toward the roller (15).

8. The adjustable adaptive rolling composite drill bit according to claim 6, characterized in that, There are multiple movable blades (24) and fixed blades (13).

9. The adjustable adaptive rolling composite drill bit according to claim 6, characterized in that, The outer surface of the movable blade (24) is also provided with a mud flow channel (25).

10. The adjustable adaptive rolling composite drill bit according to claim 9, characterized in that, There is a gap between the fixed cutter wing (13) and the movable cutter wing (24), and multiple water holes (26) are provided on the drill bit body (1). The multiple water holes (26) are respectively distributed in the center of the movable cutter wing (24) and in the mud flow channel (25) of the movable cutter wing (24).

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