Multi-blade type self-adaptive PDC (polycrystalline diamond compact) drill bit

Abstract

The invention provides a multi-blade type self-adaptive PDC drill bit and belongs to the technical field of PDC drill bits, the multi-blade type self-adaptive PDC drill bit comprises a drill bit body, blade parts and adjusting nozzles, one end of the drill bit body is a threaded end used for being connected with a drill rod, the other end of the drill bit body is a rock breaking end, the multiple blade parts are arranged at intervals in the circumferential direction of the rock breaking end, and at least one adjusting nozzle is embedded in a branch flow channel. The adjusting nozzle comprises a valve assembly, a sliding block and an elastic component. The valve assembly is arranged at the end, close to the drill bit body, of the branch flow channel and used for controlling on-off and opening of the drilling fluid flow. The sliding block is arranged in the branch flow channel in a sliding mode, and an acceleration flow channel communicating with the branch flow channel is further arranged in the sliding block. One end of the elastic component is connected with the sliding block, the other end of the elastic component is connected with the valve assembly, and the elastic component is used for providing elastic force to drive the valve assembly to telescopically slide to adaptively adjust drilling fluid flow; the pressure needed by sliding of the sliding block is larger than that needed by sliding of the valve assembly. The problem that in the prior art, the rock cleaning and cooling effects of a PDC drill bit are not stable can be effectively solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of PDC drill bits, and more particularly relates to a multi-edge adaptive PDC drill bit. Background Art

[0002] PDC drill bits are short for polycrystalline diamond compact drill bits, also known as polycrystalline diamond cutting segment drill bits or composite segment drill bits. PDC drill bits consist of a drill body, PDC cutters, and a nozzle. PDC drill bits break rock by cutting. The cutters easily penetrate the formation under the action of bit pressure, and the torque moves forward to shear the rock. Multiple PDC cutters operate simultaneously, creating more free surfaces in the rock at the bottom of the well, making it easier to break under shear. This results in high rock breaking efficiency and rapid drilling speeds.

[0003] The frequency converter is faster and slower than that of PDC drill bits, just larger to reduce the frequency of sticky holes, because the PDC drill bit has a large impact on the drill bit lifespan, so it is more convenient to use PDC drill bits to produce large-scale products with a long service life. However, simply lengthening the nozzle to shorten the distance to the bottom of the well limits the rock cleaning coverage. Moreover, the lengthened nozzle cannot dynamically adjust the flow rate and injection pressure according to the bottom of the well conditions (such as cuttings concentration and pressure changes), resulting in unstable rock cleaning and cooling effects. Summary of the Invention

[0004] The object of the present invention is to provide a multi-edge adaptive PDC drill bit to solve the problem of unstable rock cleaning and cooling effects of PDC drill bits in the prior art.

[0005] The PDC drill bit is a very powerful tool used in drills, and its operation is very important for the maintenance and maintenance of cement, cement and other building materials. The PDC drill bit is a very powerful tool used in drill bit construction. The high efficiency PDC drill bit has a very low maintenance cost and is easy to install and can withstand high pressure and high pressure. A water trough is formed between the blade portions; at least one regulating nozzle is embedded in the branch flow channel, and the regulating nozzle includes a valve assembly, a slider and an elastic component; the valve assembly is arranged at one end of the branch flow channel close to the drill bit body, and is used to control the on-off and opening of the drilling fluid flow; the slider is slidingly arranged in the branch flow channel, and has sliding damping between the slider and the branch flow channel, and an acceleration flow channel connected to the branch flow channel is also provided in the slider; one end of the elastic component is connected to the slider, and the other end is connected to the valve assembly, and the elastic component is used to provide elastic force to drive the valve assembly to extend and slide, so as to adaptively adjust the drilling fluid flow; the pressure required for the slider to slide is greater than the pressure required for the valve assembly to slide.

[0006] The multi-blade adaptive PDC drill bit provided by the present invention has the following beneficial effects: compared with the existing technology, the adjustable nozzle is in a locked state during normal drilling, and only the ordinary nozzle is working to ensure the cooling of the cutting teeth and the carrying of rock at the bottom of the well; when mud balling occurs on the drill bit, the adjustable nozzle can also realize the graded response function of "valve assembly opens first (rapid pressure relief and rock removal) → slider moves later (full flow flushing)". For example, when the rock cuttings concentration at the bottom of the well exceeds 5%, the valve assembly opens first at low pressure to increase the local chip removal flow; if the pressure continues to rise (such as severe mud balling), the slider slides to trigger full-flow channel injection, forming a rotating jet, and the rock cleaning efficiency is improved by more than 30%; after the mud balling is cleared, the displacement and pump pressure are reduced, the pressure difference is lower than the threshold, and the nozzle is locked again to protect the drill bit cutting teeth and extend its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0008] Figure 1 A schematic structural diagram of the multi-edge adaptive PDC drill bit provided in one embodiment of the present invention;

[0009] Figure 2 A schematic structural diagram of the regulating nozzle provided in one embodiment of the present invention;

[0010] Figure 3 A schematic structural diagram of the accelerating channel provided in one embodiment of the present invention;

[0011] Figure 4 A schematic structural diagram of the anti-collision limiting structure provided in one embodiment of the present invention;

[0012] Figure 5 A schematic diagram of the position structure of the valve assembly and the elastic member provided in one embodiment of the present invention;

[0013] Figure 6 A schematic structural diagram of the drill bit body provided in one embodiment of the present invention;

[0014] Among them, the reference numerals in the figures are as follows:

[0015] 10. Drill bit body; 101. Main flow channel; 102. Branch flow channel; 103. Threaded end; 104. Rock breaking end; 105. Liquid outlet; 106. Ordinary nozzle; 11. Water tank;

[0016] 20. Blade portion; 201. Blade gauge portion; 202. Blade crown; 21. Cutting structure; 211. Main cutting tooth; 212. Auxiliary cutting tooth;

[0017] 30. Adjusting nozzle; 31. Valve assembly; 311. Valve seat; 312. Valve stem; 313. Valve head; 32. Slider; 321. Accelerating flow channel; 3221. Inlet section; 3222. Contraction section; 3223. Transition section; 3224. Diffusion section; 322. Accommodating chamber; 33. Elastic member; 331. Guide rod; 332. Forward-spin spring; 333. Reverse-spin spring; 34. Fixed sleeve; 35. Housing; 36. Spiral flow channel;

[0018] 37. Pressure gain structure; 371. Friction block; 372. Limiting groove;

[0019] 40. Anti-collision limit structure; 41. Anti-collision ring; 42. Elastic spacer; 43. Buffer fluid; 44. Rubber ring. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the described embodiments are only part of the embodiments of this application, rather than all the embodiments, and the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0021] It should be further explained that the drawings and implementation methods of the present invention mainly describe the concept of the present invention. On the basis of this concept, the specific forms and settings of some connection relationships, positional relationships, power mechanisms, power supply systems, hydraulic systems and control systems may not be fully described. However, on the premise that those skilled in the art understand the concept of the present invention, those skilled in the art can implement the above-mentioned specific forms and settings in a well-known manner.

[0022] When an element is referred to as being “fixed to” or “disposed on” another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it can be directly connected to the other element or indirectly connected to the other element.

[0023] The directional words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. The terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" indicate the directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0024] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "plurality" means two or more, and "several" means one or more, unless otherwise specifically defined.

[0025] The multi-edge adaptive PDC drill bit provided by the present invention is now described.

[0026] The first embodiment of the present invention provides a multi-blade adaptive PDC drill bit, including a drill bit body 10, a blade portion 20 and an adjustment nozzle 30; the drill bit body 10 is provided with a main flow channel 101 along the axial direction, and is provided with a branch flow channel 102, the branch flow channel 102 extends obliquely to the surface of the drill bit body 10 and is connected to the main flow channel 101, one end of the drill bit body 10 is a threaded end 103 for connecting a drill rod, and the other end is a rock breaking end 104, the rock breaking end 104 is circumferentially distributed with a plurality of liquid outlet holes 105, the liquid outlet holes 105 are connected to the main flow channel 101, and a common nozzle 106 is installed in each liquid outlet hole 105; a plurality of blade portions 20 are arranged at intervals along the circumferential direction of the rock breaking end 104, the blade portion 20 is connected to the rock breaking end 104 of the drill bit body 10, and is equipped with a cutting structure 21, any two adjacent blade portions 20 are connected to the rock breaking end 104 of the drill bit body 10, and are equipped with a cutting structure 21. A water trough 11 is formed between the wings 20; at least one regulating nozzle 30 is embedded in the branch flow channel 102, and the regulating nozzle 30 includes a valve assembly 31, a slider 32 and an elastic member 33; the valve assembly 31 is arranged at one end of the branch flow channel 102 close to the drill bit body 10, and is used to control the on-off and opening of the drilling fluid flow; the slider 32 is slidably arranged in the branch flow channel 102, and has sliding damping between the branch flow channel 102, and an acceleration flow channel 321 connected to the branch flow channel 102 is also provided in the slider 32; one end of the elastic member 33 is connected to the slider 32, and the other end is connected to the valve assembly 31, and the elastic member 33 is used to provide elastic force to drive the valve assembly 31 to extend and slide, so as to adaptively adjust the drilling fluid flow; the pressure required for the slider 32 to slide is greater than the pressure required for the valve assembly 31 to slide. The cutting structure 21 includes a main cutting tooth 211 and an auxiliary cutting tooth 212 , and the blade portion 20 includes a blade gauge portion 201 and a blade crown portion 202 , wherein the blade crown portion 202 is provided with a plurality of main cutting teeth 211 , and the blade gauge portion 201 is provided with a plurality of auxiliary cutting teeth 212 .

[0027] like Figure 1 Of Figure 6As shown, the multi-blade adaptive PDC drill bit of the present invention achieves efficient rock breaking and intelligent rock cleaning through the coordinated design of the drill bit body 10, blades, and adjustable nozzles 30. The main channel 101 of the drill bit body 10 introduces drilling fluid through the drill pipe. The fluid outlet 105 of the rock breaking end 104 and the conventional nozzle 106 form a basic flushing flow field, maintaining a basic cleanliness of the wellbore. The four to six blade sections 20, evenly distributed along the circumference of the rock breaking end 104, have primary cutting teeth 211 on the blade crown 202 arranged at a 15°-25° back rake angle, breaking the formation through shearing. The secondary cutting teeth 212 (diameter 8-10 mm) on the blade gage section 201 are used to trim the wellbore wall. A water trough 11 is formed between any two adjacent blades 20. This trough 11 extends from the rock-breaking end 104 to the blade gauge portion 201. A branch channel 102 is located at the bottom of the trough 11, embedded within which is a regulating nozzle 30. This regulating nozzle 30 comprises a valve assembly 31, a slider 32, and an elastic member 33. The valve assembly 31 is positioned at the end of the branch channel 102 near the drill bit body 10. The elastic member 33 allows the valve assembly 31 to extend and retract along the axial direction of the branch channel 102. Different positions of the valve assembly 31 result in different drilling fluid flow rates. When the bottomhole cuttings concentration exceeds 5% or pressure increases, the regulating nozzle 30, through a graded response between the elastic member 33 and the pressure-boosting structure 37, increases the localized cuttings removal flow rate to 1.5-2 times the base flow rate, creating a high-speed jet that flushes the cuttings accumulation zone between the blades 20. The regulating nozzle 30 adaptively adjusts the drilling fluid injection flow rate, assisting in cuttings removal and ensuring stable rock breaking.

[0028] Compared with existing technologies, this method has two main advantages. First, it realizes multi-blade collaborative rock breaking. The main cutter 211 first contacts the formation and breaks the rock by generating shear stress through rotation. The secondary cutter 212 then polishes the wellbore wall. The stepped layout of the two prevents synchronous wear. When the main cutter wear reaches 1.2 mm, the secondary cutter fully intervenes in rock breaking. Second, it realizes intelligent rock cleaning control. The ordinary nozzle 106 provides basic flushing, and the regulating nozzle 30 is opened under pressure triggering. The flow rate is increased by accelerating the flow channel 321. In combination with the rotating jet generated by the spiral flow channel 36, a directional flushing is formed on the back of the blade 20 and the bottom of the water tank 11, clearing the rock debris accumulation in traditional blind areas. In addition, the flow distribution between the main channel 101 and the branch channel 102 is adaptively adjusted by pressure. Under basic working conditions, 90% of the flow is ejected through the ordinary nozzle 106. Under high-pressure conditions, 30%-50% of the flow is diverted to the regulating nozzle 30, realizing dynamic rock cleaning of "global flushing + local enhancement". This design breaks through the efficiency bottleneck of traditional PDC drill bits in complex formations through the deep integration of structural innovation and flow field optimization. It is particularly suitable for scenarios such as shale gas horizontal wells and deep wells that have stringent requirements for rock breaking and clearing.

[0029] like Figures 2 to 5As shown, the multi-blade adaptive PDC drill bit provided by the first embodiment of the present invention, the adjusting nozzle 30 also includes a fixed sleeve 34, a shell 35 and a spiral flow channel 36; the fixed sleeve 34 is fixedly arranged in the branch flow channel 102; one end of the shell 35 is sealed with the fixed sleeve 34, and the other end is provided with a spiral flow channel 36, and the spiral flow channel 36 is used for diffusion of drilling fluid; the slider 32 is slidably arranged in the shell 35, and the center of the slider 32 is provided with an axially through-going accommodating cavity 322, and the acceleration flow channel 321 is located in the slider 32 in the circumferential direction of the accommodating cavity 322; the valve assembly 31 is slidably connected to the accommodating cavity 322, so that when in one sliding position, one end of the valve assembly 31 is sealed and matched with the entrance of the spiral flow channel 36, and when in another sliding position, one end of the valve assembly 31 is opened with the entrance of the spiral flow channel 36.

[0030] The fixed sleeve 34 is fixedly arranged in the branch flow channel 102, and is used to determine the specific position of the regulating nozzle 30 in the branch flow channel 102. One end of the shell 35 is threaded and sealed with the fixed sleeve 34, and the other end is provided with a spiral flow channel 36. The spiral flow channel 36 is used for diffusion of drilling fluid. The slider 32 is slidably arranged inside the shell 35. At least one acceleration flow channel 321 is provided in the circumferential direction of the slider 32. In this solution, there are two acceleration flow channels 321. An axially through-going accommodating cavity 322 is provided in the center of the slider 32. An elastic member 33 is provided in the accommodating cavity 322. The second end of the elastic member 33 is connected to the valve assembly 31, and the other end of the valve assembly 31 is sealed with the entrance of the spiral flow channel 36. The elastic member 33 is used to provide elastic force to drive the valve assembly 31 to extend and slide, and adaptively adjust the drilling fluid flow rate; when the drilling fluid pressure suddenly increases, the pressure first pushes the valve assembly 31 to slide and quickly releases the pressure; when the pressure continues to act and reaches a higher threshold, the slider 32 is driven to slide; the pressure required for the slider 32 to slide is greater than the pressure required for the valve assembly 31 to slide.

[0031] When the bottom hole pressure suddenly rises, the drilling fluid directly impacts the valve assembly 31 through the acceleration channel 321, generating an axial thrust. The valve assembly 31 overcomes the elastic force of the elastic component 33 and separates from the entrance of the spiral channel 36, forming an annular gap to achieve rapid pressure relief. At this time, the slider 32 remains stationary because the friction resistance of the pressure gain structure 37 is greater than the pressure. When the pressure continues to rise to the threshold, the sum of the fluid thrust and the end face pressure of the slider 32 exceeds the total stiffness and friction resistance of the elastic component 33, and the slider 32 begins to move. The entrance of the spiral channel 36 is fully opened, and the drilling fluid forms a rotating jet through the spiral channel 36. The rotating jet generated by the spiral channel 36 forms a centrifugal force field, which expands the cuttings removal radius by 1.5 times, realizes full flow flushing, and improves the rock cleaning efficiency by 60%.

[0032] Through the synergistic effect of mechanical friction and fluid mechanics, this design breaks through the single mode of "fully closed-fully open" of traditional nozzles and realizes the intelligent switching of "slightly open to relieve pressure-fully remove rock". It is particularly suitable for complex working conditions with large fluctuations in formation pressure (such as shale gas horizontal wells), which can increase the drill bit footage efficiency by more than 25%.

[0033] like Figure 3 As shown, the multi-edge adaptive PDC drill bit provided by the first embodiment of the present invention has an accelerating flow channel 321 comprising an inlet section 3221, a contraction section 3222, a transition section 3223 and a diffusion section 3224 which are connected in sequence, wherein the inlet section 3221 is a circular tube structure, one end of which is connected to the fixed casing 34 for introducing drilling fluid; the contraction section 3222 is a conical tube structure, the large-diameter end of the contraction section 3222 is connected to the other end of the inlet section 3221, and the small-diameter end of the contraction section 3222 faces the transition section 3223, and The cone angle of the contraction section 3222 is α; the transition section 3223 is a circular tube structure, one end of the transition section 3223 is connected to the small-diameter end of the contraction section 3222, and the other end of the transition section 3223 is connected to the diffusion section 3224, and the ratio of the diameter of the transition section 3223 to the diameter of the inlet section 3221 is 0.35-0.6; the diffusion section 3224 is a conical tube structure, the small-diameter end of which is connected to the other end of the transition section 3223, and the large-diameter end of the diffusion section 3224 faces the spiral flow channel 36, and the cone angle of the diffusion section 3224 is β, where α>β.

[0034] Drilling fluid flows smoothly through inlet section 3221. In contraction section 3222, due to the sudden decrease in cross-sectional area, static pressure energy is converted into kinetic energy, forming a high-speed jet. Transition section 3223 stabilizes flow by maintaining a constant flow channel diameter, reducing turbulent energy loss. Diffusion section 3224 gradually expands its cross-sectional area, converting some of the kinetic energy into static pressure energy, creating a composite flow field of "high-speed impact + stable pressurization." Ultimately, the fluid is ejected into spiral flow channel 36 at high velocity and pressure, actuating valve head 313. Furthermore, acceleration channel 321 exhibits strong anti-clogging capabilities. The large taper angles of contraction section 3222 and diffuser section 3224 reduce the risk of cuttings retention. Combined with the flow stabilization of transition section 3223, it can pass cuttings up to 3 mm in diameter, making it suitable for drilling fluid environments with high solids content.

[0035] like Figure 5As shown, the multi-blade adaptive PDC drill bit provided by the first embodiment of the present invention, the valve assembly 31 includes a valve seat 311, a valve stem 312 and a valve head 313; the valve seat 311 is slidably arranged in the accommodating cavity 322, and the second end of the elastic member 33 is connected to the valve seat 311; the first end of the valve stem 312 is fixedly connected to the center of the valve seat 311, and the second end extends to the spiral flow channel 36; the valve head 313 has an inverted cone structure, which is fixed to the second end of the valve stem 312, and the valve head 313 is sealed with the entrance of the spiral flow channel 36; when the valve assembly 31 slides, the valve head 313 disengages from or adheres to the sealing surface, thereby controlling the on-off and opening of the wellbore fluid flow during drilling.

[0036] The valve assembly 31 achieves precise control of the drilling fluid flow rate through the linkage structure of the valve seat 311, the valve stem 312 and the valve head 313. Specifically, the valve seat 311 is nested in the accommodating cavity 322 of the slider 32, and the second end of the elastic member 33 abuts the valve seat 311 to provide an initial preload. The first end of the valve stem 312 is fixedly connected to the center of the valve seat 311, and the second end of the valve stem 312 extends to the entrance of the spiral flow channel 36. The inverted conical valve head 313 is fixedly mounted on the end of the valve stem 312, forming a line contact seal with the conical sealing surface at the entrance of the spiral flow channel 36. When the drilling fluid is accelerated through the acceleration flow channel 321 (including the contraction section 3222 and the diffusion section 3224), the high-speed fluid directly impacts the inverted conical surface of the valve head 313, generating an axial thrust. The thrust is transmitted to the valve seat 311 via the valve head 313 and the valve stem 312, overcoming the pre-tightening force of the elastic member 33, thereby driving the valve seat 311 and the elastic member 33 to move axially synchronously, so that the valve head 313 is separated from the sealing surface of the entrance of the spiral flow channel 36, thereby opening the flow channel.

[0037] In the static state, the preload of elastic member 33 causes valve head 313 to fit tightly against the sealing surface. When the fluid thrust exceeds the preload, valve head 313 gradually separates from the sealing surface, and the flow channel opening increases linearly with the displacement of valve head 313. When the pressure decreases, elastic member 33 releases stored energy, pushing the valve seat 311-valve stem 312-valve head 313 assembly in the opposite direction. The inverted conical surface of valve head 313 re-embeds the sealing surface, and the self-centering characteristics of the conical surface match achieve precise resetting. This valve assembly 31 adopts the design concept of "direct pressure bearing of valve head 313 + mechanical rigid linkage + elastic dynamic balance", which solves the technical problems of slow response, low precision, and easy erosion of traditional valve assembly 31, providing core support for the efficient rock clearing of PDC drill bits in complex formations.

[0038] like Figure 5As shown, the multi-blade adaptive PDC drill bit provided by the first embodiment of the present invention, the elastic member 33 includes a guide rod 331, a forward spring 332 and a reverse spring, the guide rod 331 is arranged in the accommodating chamber 322, and a fastener is provided after the first end of the guide rod 331 passes through the bottom wall of the accommodating chamber 322, and the second end of the guide rod 331 is slidably connected to the valve seat 311; the reverse spring 333 is sleeved on the guide rod 331, the forward spring 332 is sleeved on the outside of the reverse spring 333, and one end of the forward spring 332 and the reverse spring 333 are connected to the valve seat 311, and the other end is connected to the bottom wall of the accommodating chamber 322. In the working state, the forward spring 332 is in a stretched state, and the reverse spring 333 is in a compressed state. The valve head 313 is sealed and matched with the entrance of the spiral flow channel 36 under the cooperation of the forward spring 332 and the reverse spring 333.

[0039] In the present invention, the elastic forces of the forward-spinning spring 332 and the reverse-spinning spring 333 work together to achieve a reliable seal between the valve head 313 and the inlet of the spiral flow channel 36. Specifically, the elastic member 33 adopts a combined structure of a "guide rod 331 + forward-spinning spring 332 + reverse-spinning spring 333." The guide rod 331 is arranged axially along the accommodating chamber 322. The first end penetrates the bottom wall of the accommodating chamber 322 and is fixed by a circular fastener (such as a limit nut) via a threaded connection or welding to limit the axial displacement of the guide rod 331. The second end of the guide rod 331 is a smooth cylindrical surface. The second end of the guide rod 331 forms a clearance fit with the guide hole in the center of the valve seat 311, allowing the valve seat 311 to slide freely along the guide rod 331. The reverse-rotation spring 333 is mounted on the outside of the guide rod 331, with one end abutting the valve seat 311 and the other end abutting the bottom wall of the accommodating chamber 322. The forward-rotation spring 332 is mounted on the outside of the reverse-rotation spring 333, with one end connected to the valve seat 311 and the other end fixed to the bottom wall of the accommodating chamber 322. During operation, the forward-rotation spring 332 is always in a pre-tensioned state, providing a tensile force F1 toward the accommodating chamber 322; the reverse-rotation spring 333 is in a pre-compressed state, providing a thrust F2 away from the accommodating chamber 322. In the absence of drilling fluid pressure, the combined forces of F1 and F2 tightly align the inverted conical sealing surface of the valve head 313 with the conical surface at the inlet of the spiral flow channel 36, forming an initial seal. This design offers two technical advantages: First, the spring forces of the forward and reverse-rotation springs 333 are directed in opposite directions. When the downhole temperature rises, causing the spring material to thermally expand, the changes in F1 and F2 offset each other. After testing, it was found that under a high temperature environment of 150°C, the fluctuation amplitude of the elastic force difference between F1 and F2 was less than 5%, which is much lower than the 20% fluctuation of a single spring structure, ensuring that the valve head 313 responds stably under high pressure difference conditions. Secondly, the dual spring structure balances the force on the valve seat 311 by preloading, so that the overall deformation is controlled within a small range of 0.5-1.0mm. During installation, it is only necessary to adjust the axial position of the guide rod 331 through the fasteners to simultaneously complete the preload setting of the dual springs. There is no need for a complicated pressure debugging process, and it is adapted to the rapid assembly requirements of the drilling site. This structure is particularly suitable for high-temperature and high-pressure formations. Through the mechanical coupling effect of the dual springs, it not only ensures the sensitive response of the valve head 313 to changes in drilling fluid pressure, but also improves the reliability of the elastic component 33 in extreme environments and extends the service life of the regulating nozzle 30. A seal is provided between the valve seat 311 and the accommodating chamber 322. The seal can be an O-ring, which is embedded in the sealing groove arranged circumferentially on the valve seat 311 to achieve radial sealing;

[0040] like Figures 3 to 5As shown, the multi-blade adaptive PDC drill bit provided by the first embodiment of the present invention, the adjusting nozzle 30 also includes a pressure gain structure 37, the pressure gain structure 37 includes a friction block 371 and a limiting groove 372; the friction block 371 is arranged on the inner wall of the shell 35 along the axial direction thereof, and a friction ridge is provided on the surface of the friction block 371; the limiting groove 372 is provided on the outer circumferential surface of the slider 32 and is adapted to the friction block 371, and a high friction coefficient coating is provided on the limiting groove 372 and the inner wall of the limiting groove 372, by increasing the friction force of the contact surface, so that the sliding pressure of the slider 32 is greater than the sliding pressure of the valve head 313.

[0041] The pressure gain structure 37 achieves a graded response mechanism through a friction pair design: "low-pressure valve opening for pressure relief, high-pressure slider 32 for linkage." Specifically, a rectangular friction block 371 is axially positioned on the inner wall of the housing 35, with trapezoidal friction ridges machined onto its surface. The outer circumference of the slider 32 features a corresponding rectangular retaining groove 372, which mates with the friction block 371. The inner wall of the retaining groove 372 is spray-coated with a nickel-based tungsten carbide high-friction coating, forming a mechanical resistance interface between the friction block 371 and the inner wall of the retaining groove 372. When bottomhole pressure suddenly rises, a relatively small pressure can force the valve head 313 to open rapidly, overcoming the preload force of the elastic member 33 and achieving primary pressure relief, thus preventing high-pressure impact on the drill bit structure. When pressure continues to rise to a set threshold, the friction block 371 comes into close contact with the coating of the retaining groove 372. The meshing resistance between the ridges and the coating forces the slider 32 to slide synchronously, triggering a secondary full-flow flush. At this point, the valve head 313 opening and the slider 32 displacement increase in tandem, achieving significant pressure relief while enhancing rock clearing.

[0042] The beneficial effects of this design include: ① The mechanical resistance of the friction pair precisely sets the operating pressure difference between the valve head 313 and the slider 32, ensuring that only the valve head 313 opens quickly to release pressure during small pressure fluctuations, avoiding the waste of hydraulic energy caused by erroneous triggering of full-flow flushing; ② When the pressure is low, the valve head 313 opens slightly to release pressure, maintaining basic cleanliness of the well bottom; when the pressure exceeds the threshold, the slider 32 increases the flow rate, forming a high-speed jet to flush the area where cuttings accumulate, improving the rock cleaning efficiency by more than 40% compared to the traditional single-stage structure; ③ The design of the valve head 313 actuating before the slider 32 can release 30%-50% of the impact energy at the moment of sudden pressure change (<0.1s), reducing the impact load of high pressure on the internal structure of the drill bit and extending the service life of the seal and elastic component 33;

[0043] like Figure 4As shown, in the multi-blade adaptive PDC drill bit provided by the first embodiment of the present invention, anti-collision limit structures 40 are provided at both ends of the slider 32, and the anti-collision limit structure 40 includes an anti-collision ring 41, an elastic spacer 42, a buffer fluid 43 and a rubber ring 44; the anti-collision ring 41 is provided at the end of the slider 32, and the anti-collision ring 41 is a cavity structure; the elastic spacer 42 is provided in the anti-collision ring 41, dividing the anti-collision ring 41 into a first compartment and a second compartment; the buffer fluid 43 is provided in the first compartment, and the buffer fluid 43 is a viscous fluid; the rubber ring 44 is provided in the second compartment.

[0044] The anti-collision ring 41 is made of a shape memory alloy, which is elastic and compressible. The interior of the anti-collision ring 41 is a hollow structure, and an elastic spacer 42 is provided on its inner wall. The elastic spacer 42 is integrally formed with the anti-collision ring 41 and divides the interior of the anti-collision ring 41 into a first compartment and a second compartment. The first compartment is filled with a shear buffer fluid 43 (such as a silicone oil-based non-Newtonian fluid), and the second compartment is embedded with a rubber ring 44. The anti-collision limit structure 40 can limit excessive movement of the slider 32 to prevent excessive opening of the valve head 313. The rubber ring 44 provides initial buffering, and then the buffer fluid 43 flows under pressure to achieve secondary damping. At the same time, the rubber ring 44 acts as a seal in the second compartment to prevent drilling fluid intrusion. When the impact load disappears, the elastic force of the elastic spacer 42 and the rubber ring 44 pushes the slider 32 to reset, ensuring that it returns to its initial position. The anti-collision limit structure 40 combines the limiting, buffering, sealing and reset functions, improving the reliability of the regulating nozzle 30 under high-pressure impact conditions.

[0045] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention are intended to be construed as follows.

Claims

1. Multi-edge adaptive PDC drill bit, characterized by: include: A drill bit body (10) is provided with a main flow channel (101) along the axial direction and a branch flow channel (102), wherein the branch flow channel (102) extends obliquely to the surface of the drill bit body (10) and is communicated with the main flow channel (101); one end of the drill bit body (10) is a threaded end (103) for connecting to a drill rod, and the other end is a rock breaking end (104); the rock breaking end (104) is provided with a plurality of liquid outlet holes (105) distributed circumferentially, wherein the liquid outlet holes (105) are communicated with the main flow channel (101), and a common nozzle (106) is installed in each of the liquid outlet holes (105); A plurality of blade wing portions (20) are arranged at intervals along the circumferential direction of the rock breaking end (104), the blade wing portions (20) are connected to the rock breaking end (104) of the drill bit body (10), and are equipped with a cutting structure (21), and a water trough (11) is formed between any two adjacent blade wing portions (20); at least one regulating nozzle (30) embedded in the branch flow channel (102); Wherein, the regulating nozzle (30) comprises: A valve assembly (31) is provided at one end of the branch flow channel (102) close to the drill bit body (10) and is used to control the flow of drilling fluid and the opening degree; a slider (32) slidably disposed in the branch flow channel (102) and having sliding damping between the slider and the branch flow channel (102); an elastic member (33), one end of which is connected to the slider (32) and the other end of which is connected to the valve assembly (31), wherein the elastic member (33) is used to provide elastic force to drive the valve assembly (31) to extend and slide, so as to adaptively adjust the flow rate of drilling fluid; The pressure required for the sliding block (32) to slide is greater than the pressure required for the sliding of the valve assembly (31).

2. The multi-edge adaptive PDC drill bit according to claim 1, characterized in that: The cutting structure (21) comprises a main cutting tooth (211) and an auxiliary cutting tooth (212); the blade wing portion (20) comprises a blade wing gauge portion (201) and a blade wing crown portion (202); wherein the blade wing crown portion (202) is provided with a plurality of main cutting teeth (211), and the blade wing gauge portion (201) is provided with a plurality of auxiliary cutting teeth (212).

3. The multi-edge adaptive PDC drill bit according to claim 1, characterized in that: The regulating nozzle (30) further comprises a fixed sleeve (34) and a housing (35), wherein the fixed sleeve (34) is fixedly arranged in the branch flow channel (102); one end of the housing (35) is sealedly connected to the fixed sleeve (34), and the other end is provided with a spiral flow channel (36), wherein the spiral flow channel (36) is used for diffusing drilling fluid; The slider (32) is slidably disposed in the housing (35); an axially penetrating accommodation cavity (322) is provided at the center of the slider (32); and the accelerating flow channel (321) is located in the slider (32) in the circumferential direction of the accommodation cavity (322); The valve assembly (31) is slidably connected to the accommodating chamber (322) so that when in one sliding position, one end of the valve assembly (31) is sealed and matched with the entrance of the spiral flow channel (36), and when in another sliding position, one end of the valve assembly (31) and the entrance of the spiral flow channel (36) are open.

4. The multi-edge adaptive PDC drill bit according to claim 3, wherein: The accelerating flow channel (321) comprises an inlet section (3221), a contraction section (3222), a transition section (3223) and a diffusion section (3224) which are connected in sequence; The inlet section (3221) is a circular tube structure, and one end of the inlet section (3221) is connected to the fixed casing (34) for introducing drilling fluid. The contraction section (3222) is a conical cylinder structure, the large-diameter end of the contraction section (3222) is connected to the other end of the inlet section (3221), the small-diameter end of the contraction section (3222) faces the transition section (3223), and the cone angle of the contraction section (3222) is α; The transition section (3223) is a circular tube structure. One end of the transition section (3223) is connected to the small-diameter end of the contraction section (3222), and the other end of the transition section (3223) is connected to the diffusion section (3224). The ratio of the diameter of the transition section (3223) to the diameter of the inlet section (3221) is 0.35-0.

6. The diffusion section (3224) is a conical cylinder structure, the small-diameter end of which is connected to the other end of the transition section (3223), the large-diameter end of the diffusion section (3224) faces the spiral flow channel (36), and the cone angle of the diffusion section (3224) is β, where α>β.

5. The multi-edge adaptive PDC drill bit according to claim 3, characterized in that: The valve assembly (31) comprises: A valve seat (311) is slidably disposed in the accommodating cavity (322), and the second end of the elastic member (33) is connected to the valve seat (311); A valve stem (312), one end of which is fixedly connected to the center of the valve seat (311), and the other end of which extends to the spiral flow channel (36); The valve head (313) is in an inverted cone-shaped structure and is fixed to the second end of the valve stem (312). The valve head (313) is in sealing cooperation with the entrance of the spiral flow channel (36); When the valve assembly (31) slides, the valve head (313) separates from or fits into the sealing surface, thereby controlling the flow rate and opening of the drilling fluid.

6. The multi-edge adaptive PDC drill bit according to claim 5, characterized in that: The elastic member (33) includes a guide rod (331), a forward-rotating spring (332) and a reverse-rotating spring (333); the guide rod (331) is arranged in the accommodating cavity (322); a fastener is provided after the first end of the guide rod (331) passes through the bottom wall of the accommodating cavity (322); the second end of the guide rod (331) is slidably connected to the valve seat (311); the reverse-rotating spring (333) is sleeved on the guide rod (331); the forward-rotating spring (332) is sleeved on the outside of the reverse-rotating spring (333); and one end of each of the forward-rotating spring (332) and the reverse-rotating spring (333) is connected to the valve seat (311) and the other end is connected to the bottom wall of the accommodating cavity (322).

7. The multi-edge adaptive PDC drill bit according to claim 3, wherein: The regulating nozzle (30) further comprises a pressure gain structure (37), wherein the pressure gain structure (37) comprises: A friction block (371) is arranged on the inner wall of the housing (35) along the axial direction thereof, and friction ridges are arranged on the surface of the friction block (371); The limiting groove (372) is provided on the outer surface of the slider (32) and is adapted to the friction block (371), and a high friction coefficient coating is provided on the limiting groove (372) and the inner wall of the limiting groove (372), so that the sliding pressure of the slider (32) is greater than the sliding pressure of the valve head (313) by increasing the friction force of the contact surface.

8. The multi-edge adaptive PDC drill bit according to claim 5, wherein: A sealing member is provided between the valve seat (311) and the accommodating cavity (322).

9. The multi-edge adaptive PDC drill bit according to claim 3, wherein: Anti-collision limiting structures (40) are provided at both ends of the slider (32), and the anti-collision limiting structures (40) include: An anti-collision ring (41) is arranged at the end of the slider (32), and the anti-collision ring (41) is a cavity structure; an elastic spacer (42) disposed in the anti-collision ring (41) to divide the anti-collision ring (41) into a first compartment and a second compartment; A buffer fluid (43) is disposed in the first compartment, wherein the buffer fluid (43) is a viscous fluid; A rubber ring (44) is arranged in the second compartment.

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