Flexible PDC drill bit and composite drill bit

Abstract

The invention relates to the technical field of drilling exploitation, in particular to drilling equipment therein, in particular to a flexible PDC drill bit and a composite drill bit, the flexible PDC drill bit comprises a drill bit body and a blade body, and a plurality of cutting elements are formed on the blade body; at least one blade wing comprises a buffering part and a supporting part, a separation groove is formed between the buffering part and the supporting part, and the cutting element is arranged on the buffering part. By means of the combined blade body composed of the buffering part and the supporting part and the separation grooves with certain intervals, the variable stiffness characteristic that the drill bit can be adjusted in a self-adaptive mode along with load changes is achieved. When the drill bit encounters a violent instantaneous impact load, the blade bodies can generate micro displacement due to the existence of the separation grooves, and the buffering effect is achieved. The service life of the drill bit in a deep well and a stratum difficult to drill is greatly prolonged, and the non-production time and the comprehensive drilling cost are remarkably reduced.

Description

Technical Field

[0001] This invention relates to the field of drilling and mining technology, specifically to drilling equipment therein, and more particularly to a flexible PDC drill bit and a composite drill bit. Background Technology

[0002] Polycrystalline diamond compact (PDC) drill bits are widely used in oil and gas drilling due to their extremely high hardness, excellent wear resistance, and lack of moving parts. They are particularly useful in drilling soft to medium-hard formations, where their mechanical drilling speed and service life are significantly superior to traditional roller cone bits. With increasing drilling depths and increasingly complex exploration and development environments, the demand for PDC drill bits in deep wells, ultra-deep wells, and complex and difficult-to-drill formations such as gravel-bearing and mixed soft-hard formations is also growing.

[0003] However, PDC drill bits often face severe challenges when dealing with complex and heterogeneous formations. Due to the high hardness but high brittleness of PDC cutting teeth, their impact resistance is relatively poor. Existing conventional PDC drill bits typically employ an integral rigid structure where the cutter blades are molded as a single piece with the drill body. While this design ensures effective transmission of drilling pressure and torque, it also results in high overall rigidity. When the drill bit penetrates complex and heterogeneous formations, the cutting teeth on the cutter blades are subjected to enormous impact loads instantaneously. Under rigid contact conditions, the impact load acts for an extremely short time, leading to a sharp increase in instantaneous impact force. This impact load, far exceeding the strength limit of the cutting tooth material, can easily cause the cutting teeth to chip, delaminate, or even fracture entirely, leading to premature drill bit failure. This severely shortens the drilling footage per bit, forcing frequent tripping and bit replacements during drilling operations, significantly increasing non-productive time and drilling costs.

[0004] Existing impact-resistant PDC drill bits mainly employ specially shaped teeth with excellent impact resistance, optimized drill bit stability structure design, and the addition of auxiliary cutting structures or buffer structures. While these technologies alleviate impact to some extent, they do not fundamentally change the rigid contact between the drill bit and the formation.

[0005] Therefore, existing PDC drill bits still have room for improvement in terms of impact resistance and should be optimized to enhance their impact resistance and ensure their stability and reliability during operation. Thus, a more reasonable technical solution is needed to address the technical problems existing in the current technology. Summary of the Invention

[0006] The main objective of this invention is to provide a flexible PDC drill bit and a composite drill bit. By optimizing the blade structure, the cutting teeth are set in the flexible part and the cutting is achieved through the support structure at the rear, thereby optimizing the overall rigidity of the drill bit and maintaining the stability and reliability of the drill bit structure during drilling and cutting.

[0007] To achieve the above-mentioned technical effects, the flexible PDC drill bit solution adopted in this invention is as follows: A flexible PDC drill bit includes a drill body and a cutter wing body, with a plurality of cutting elements formed on the cutter wing body; at least one cutter wing includes a buffer portion and a support portion, with a partition groove formed between the buffer portion and the support portion, and the cutting elements are disposed in the buffer portion.

[0008] The aforementioned flexible PDC drill bit has a cutting element in the buffer section for cutting and drilling during operation. The support section behind it provides support force to prevent the buffer section from exceeding the set maximum deformation after elastic deformation, thereby optimizing the rigidity of the entire PDC drill bit and enabling it to work normally when encountering complex environments and high-frequency impact loads.

[0009] Furthermore, the width of the dividing groove is the maximum elastic deformation that the buffer part can undergo. Here, optimization is proposed, and one feasible option is that the width of the dividing groove is 0 ≤ δ ≤ 1 mm. When adopting the above scheme, various different deformations can be considered. For example, a dividing groove of equal width can be directly set to limit the deformation of the buffer part; or a wider dividing groove can be set, and corresponding secondary limiting structures can be set within the groove to prevent excessive deformation of the buffer part, achieving the same deformation limiting effect.

[0010] Furthermore, the internal structure of the partition groove is optimized, specifically: a limiting structure is formed within the partition groove, and the limiting structure is connected and fixed to the buffer part, or the limiting structure is connected and fixed to the support part. When adopting the above scheme, the limiting structure can be integrally formed with the buffer part, or separately set and fixed by connecting parts; or the limiting structure can be integrally formed with the support part, or separately set and fixed by connecting parts.

[0011] Furthermore, besides limiting the buffer section in the circumferential tangential direction, the dividing groove can also limit it in multiple directions. Here, we optimize and propose one feasible option: the dividing groove extends radially along the blade to form a straight groove, an arc-shaped groove, or a bent groove. When using the above scheme, the straight groove is used to limit the amount of deformation in the circumferential tangential direction, while the arc-shaped and bent grooves can be used to limit the amount of deformation in both the circumferential tangential and radial directions. This ensures that the relative position of the buffer section and the support section deforms within a set range.

[0012] Furthermore, in other solutions, the circumferential tangential and radial positions of the buffer section can be limited in various ways. Here, we optimize and propose some feasible options: a constraint structure is formed on the support section, and an extension structure corresponding to the constraint structure is formed on the buffer section. The extension structure and the constraint structure cooperate to form a gap and prevent the deformation of the buffer section in the circumferential tangential direction from exceeding the maximum width of the partition groove; and / or, a constraint structure is formed on the support section, and an extension structure corresponding to the constraint structure is formed on the buffer section. The extension structure and the constraint structure cooperate to form a gap and prevent the deformation of the buffer section in the circumferential radial direction from exceeding the maximum width of the partition groove. When adopting the above solutions, the constraint structure can be integrally formed with the support section, or it can be set separately and fixed by connecting fasteners.

[0013] Furthermore, the constraint structure and extension structure can adopt various schemes, and their structures are not limited to a single one. Here, we optimize and propose one feasible option: the constraint structure is set on the front side and / or the upper end face of the support part, and the constraint structure includes a constraint protrusion or a constraint groove. When adopting the above scheme, the constraint structure can be a square or rectangular protrusion, or a groove structure of a corresponding shape, while the extension structure is set to cooperate with the constraint structure to form a snap-fit ​​fit.

[0014] In some schemes, in addition to using the above-mentioned constraint structure and extension structure to achieve positive constraints, the above-mentioned constraint structure and extension structure can also be used to form reverse constraints.

[0015] Furthermore, the support components can be arranged in various ways and are not limited to a single form. Here, we optimize and propose one feasible option: several support components are arranged on the rear side of the buffer section, with partition grooves forming between adjacent support components. When adopting the above scheme, the multiple partition grooves between multiple support components provide a larger elastic deformation space, which can provide more optimized stiffness and a more feasible drilling scheme for different complex geological conditions, making the overall structure of the drill bit more stable and reliable.

[0016] Furthermore, to improve the cutting effect, in addition to setting cutting elements on the buffer section, the overall structure can be optimized. One feasible option is to set auxiliary cutting elements on the support section. When adopting the above solution, the auxiliary cutting elements can use various cutting teeth.

[0017] Furthermore, there are multiple possible arrangements for the buffer and support components, and they are not limited to a single one. Here, we optimize and propose one feasible option: the buffer and support components are separate from the cutter wing body and fixed together after assembly; or, the buffer and support components are integrally formed with the cutter wing body, and the support component is separate from the cutter wing body and fixed together after assembly; or, the buffer and support components are separate from the cutter wing body and fixed together after assembly, while the support component is integrally formed with the cutter wing body. When using the above solutions, the buffer and / or support components, when separated from the drill bit body, can be connected and fixed by welding.

[0018] Furthermore, the combination of the buffer and the support can adopt more schemes. Here, we optimize and propose one feasible option: the front side of the support forms several mounting groove structures, the buffer is located within the mounting groove structures, and the two sides and rear side of the buffer in the cutting direction form separation grooves with the support. When adopting the above scheme, the mounting groove structure can extend downward from the upper end of the support or extend backward from the front side of the support. After the buffer is fitted into the mounting groove structure, it is fastened by a connector.

[0019] The above content discloses a structure of a flexible PDC drill bit. The present invention also provides another structure of a flexible PDC drill bit.

[0020] Specifically, a flexible PDC drill bit includes a drill body and a cutter wing body, with a plurality of cutting elements formed on the cutter wing body; it includes at least one flexible cutter wing, with an additional structure formed on the rear side of the flexible cutter wing, the additional structure being used to support the flexible cutter wing and prevent the elastic deformation of the flexible cutter wing from exceeding the maximum allowable value α.

[0021] The flexible PDC drill bit disclosed here provides flexible blades that can deform during operation. It also provides an alternative support solution, specifically by supporting the flexible blades with an additional structure, which makes the flexible blades and the drill bit body more integrated and allows for greater elastic deformation.

[0022] Furthermore, the layout of the additional structure can adopt various schemes and is not limited to one. Here, we optimize and propose one feasible option: the additional structure extends from the drill body toward the flexible cutter wing or from the adjacent rear cutter wing toward the flexible cutter wing. The additional structure is in contact with the flexible cutter wing or forms a gap. When the additional structure forms a gap with the flexible cutter wing, the width of the gap is 0≤α≤1mm. When adopting the above scheme, the additional structure can be a single support structure or multiple support structures.

[0023] Furthermore, the additional structure can be configured in various ways. Here, we optimize and propose one feasible option: the front end of the additional structure is connected to the flexible blade wing, and the rear end is integrally formed or connected to the adjacent blade wing; or, the front end of the additional structure is separate from the flexible blade wing, and the rear end is integrally formed or connected to the adjacent blade wing. When adopting the above scheme, adjacent blades can be connected sequentially through the additional structure, or all blades can be divided into several groups, and additional structures can be set within each group for connection.

[0024] Furthermore, when fixing the additional structure, the following scheme can be adopted: when the additional structure is connected to the flexible blade or adjacent blade in a connecting and mating manner, the connecting and mating includes surface contact and connection by fasteners, and also includes hole and shaft mating and connection by anti-reverse components.

[0025] Furthermore, the additional structure includes a support column structure, an elastomer structure, and a rolling element structure.

[0026] Furthermore, due to the addition of a rigidity-enhancing structure, the structure of the cutter wing itself can be optimized. One feasible option is proposed here: the thickness of the flexible cutter wing gradually increases with its height, or the thickness at the connection between the flexible cutter wing and the drill bit body is a first thickness, and the thickness at the location where the cutting element is set on the flexible cutter wing is a second thickness, with the second thickness being greater than the first thickness. When adopting the above scheme, one side of the flexible cutter wing is a sloped surface, an arc surface, or a stepped surface.

[0027] The above describes the flexible PDC drill bit. The present invention also provides a composite drill bit.

[0028] A composite drill bit includes the flexible PDC drill bit described above, wherein the drill bit body is made of composite material; or, a composite cutting structure is provided on the cutter wings of the drill bit body; or, a composite hydraulic structure is provided on the drill bit body.

[0029] Specifically, when the drill bit body is made of composite materials, it can adopt a matrix composite, using powder metallurgy + liquid phase sintering process to construct multiphase composite materials, and the non-magnetic design can be used for measurement while drilling (MWD); or a steel composite, using a high-strength alloy steel matrix + surface hardening composite strategy, which can be regenerated multiple times after wear by welding and re-tooth arrangement, with obvious advantages in the whole life cycle cost; or a steel-matrix composite, which can be regenerated multiple times after wear by welding and re-tooth arrangement, with obvious advantages in the whole life cycle cost.

[0030] When the drill bit body's cutter blades are equipped with a composite cutting structure, a main-backup tooth composite can be used. During normal drilling, only the main tooth works; when encountering hard interlayers (such as flint nodules) that cause the main tooth to wear or fracture, the backup tooth automatically takes over the cutting, preventing the drill bit from "losing its bottom". Alternatively, the drill bit body can use a PDC-impregnated diamond composite for multi-mechanism rock breaking in extremely hard and highly abrasive formations (such as granite and quartz sandstone). Alternatively, the drill bit body can use a composite of irregular tooth geometry, such as combining ridged teeth, conical teeth, axe-shaped teeth, etc., with conventional planar teeth to achieve spatial composite.

[0031] When the power transmission structure of the drill bit body is mechanically combined, it can be set as a PDC-roller cone hybrid drill bit, which utilizes the shearing action of PDC and the crushing / impact action of roller cone to form a synergistic dual rock breaking mechanism; it can also be set as a rotary impact composite mechanism, integrating a high-frequency impactor and a conventional PDC drill bit.

[0032] When the drill bit body is equipped with a combination of hydraulic structure and flow channel functions, it can be configured to form a jet-flood composite, a variable diameter flow channel composite, an adaptive hydraulic adjustment scheme, etc.

[0033] When intelligent features and functional expansion are combined on the drill bit body, they can be configured as a sensor-actuator integrated composite solution or a drilling-while-reaming composite solution.

[0034] Compared with the prior art, some of the beneficial effects of the technical solution disclosed in this invention include: 1. The combined cutter wing body, consisting of a buffer section and a support section, utilizes spaced partition grooves to give the drill bit adaptive stiffness characteristics that change with load. When the drill bit encounters a severe instantaneous impact load, the cutter wing body can undergo a slight displacement due to the presence of the partition grooves, achieving a buffering effect.

[0035] 2. As the external load continues to act, the partition groove gradually compresses and closes. After the buffer and support parts are fully in contact, the overall stiffness of the cutter blade increases significantly, quickly returning to a rigid cutting state, ensuring the drill bit's continuous crushing and penetration of the formation. Simultaneously, different partition surface shapes can create different buffering and stiffness recovery effects, providing different adaptive effects for different formations.

[0036] 3. By adding, constraining, and extending structures, the overall strength and reliability of the blade are ensured while achieving flexible cutting.

[0037] 4. While taking into account both impact resistance and rock-breaking rigidity, it significantly extends the service life of the drill bit in deep wells and difficult-to-drill formations, and significantly reduces non-productive time and overall drilling costs. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a top view of the cutter wing of the flexible PDC drill bit in this invention.

[0040] Figure 2 yes Figure 1 Side view of the blade wing body.

[0041] Figure 3 yes Figure 2 The first structure is the cross-sectional view of section AA in the diagram.

[0042] Figure 4 yes Figure 2 The second structure is the sectional view of section AA in the figure.

[0043] Figure 5 It is a structure that combines a buffer section and a support section on the drill bit body.

[0044] Figure 6 It is another configuration of the buffer and support parts on the drill bit body.

[0045] Figure 7 This is a schematic diagram of a partition groove between the buffer section and the support section.

[0046] Figure 8 This is the first schematic diagram of the partition groove after being sectioned along point AA.

[0047] Figure 9 This is the second schematic diagram of the partition groove after being viewed in section AA.

[0048] Figure 10 This is the third schematic diagram of the partition groove (forming a constraint structure) after being sectioned along AA.

[0049] Figure 11 This is the fourth schematic diagram of the partition groove (forming a constraint structure) after being viewed in section AA.

[0050] Figure 12 This is the fifth schematic diagram of the partition groove (forming a constraint structure) after being sectioned along AA.

[0051] Figure 13 This is the sixth schematic diagram of the partition groove (forming a constraint structure) after being sectioned along AA.

[0052] Figure 14This is a schematic diagram of the first type of combined installation of the buffer section and the support section.

[0053] Figure 15 This is a schematic diagram of the second type of combined installation of the buffer section and the support section.

[0054] Figure 16 This is a schematic diagram of the third type of combined installation of the buffer section and the support section.

[0055] Figure 17 This is the first schematic diagram showing the arrangement of multiple support parts (the opening width of the dividing groove is not 0).

[0056] Figure 18 This is the first schematic diagram showing the arrangement of multiple support parts (the width of the dividing groove is 0).

[0057] Figure 19 This is a second schematic diagram showing the arrangement of multiple support parts (the opening width of the partition groove is not 0).

[0058] Figure 20 This is a second schematic diagram showing the arrangement of multiple support parts (the width of the dividing groove is 0).

[0059] Figure 21 This is a third type of schematic diagram with multiple support parts arranged in a way that is not zero (the opening width of the partition groove is not zero).

[0060] Figure 22 This is a third schematic diagram showing the arrangement of multiple support parts (the width of the dividing groove is 0).

[0061] Figure 23 This is the fourth type of diagram showing multiple support parts arranged in a specific pattern.

[0062] Figure 24 This is a schematic diagram of a variable limiting structure installed inside the partition groove.

[0063] Figure 25 This is the fifth schematic diagram showing the arrangement of multiple support parts.

[0064] Figure 26 This is the sixth schematic diagram showing the arrangement of multiple support parts.

[0065] Figure 27 This is the seventh schematic diagram showing the arrangement of multiple support parts.

[0066] Figure 28 This is the first schematic diagram for setting up additional structures.

[0067] Figure 29 This is the first schematic diagram showing the change in blade wing thickness after the additional structure is added.

[0068] Figure 30This is the second schematic diagram showing the change in blade wing thickness after the additional structure is added.

[0069] Figure 31 This is the second schematic diagram for setting up additional structures.

[0070] Figure 32 This is the third schematic diagram with additional structures.

[0071] Figure 33 This is the fourth schematic diagram for setting up additional structures.

[0072] Figure 34 This is the fifth schematic diagram for setting up additional structures.

[0073] Figure 35 This is a partial sectional view showing the additional structure of the elastomer.

[0074] Figure 36 This is a partial sectional view showing the additional structure for the rolling element.

[0075] Figure 37 This is a stress change cloud diagram of a conventional PDC drill bit airfoil when subjected to an instantaneous lateral impact.

[0076] Figure 38 This is a stress change cloud diagram of the flexible PDC drill bit airfoil when subjected to an instantaneous lateral impact load.

[0077] Figure 39 This is a comparison of the stress changes over time between the flexible PDC drill bit airfoil and the conventional PDC drill bit airfoil under instantaneous lateral impact load.

[0078] Figure 40 This is a comparison of the strain over time between a flexible PDC drill bit airfoil and a conventional PDC drill bit airfoil under instantaneous lateral impact load.

[0079] In the above diagram, the meanings of each label are as follows: 1. Drill body; 2. Cutting blade; 21. Buffer section; 211. Buffer section partition; 22. Support section; 221. Support section partition; 23. Separator groove; 24. Additional structure; 25. Constraint structure; 3. Cutting element; 31. Auxiliary cutting element. Detailed Implementation

[0080] The following description, in conjunction with the accompanying drawings and specific embodiments, further illustrates this embodiment.

[0081] In view of the many shortcomings of the prior art, the following embodiments are optimized and overcome the defects of the prior art.

[0082] Example 1 like Figure 1As shown, this embodiment provides a flexible PDC drill bit, including a drill bit body 1 and a cutter blade 2 body, with a plurality of cutting elements 3 formed on the cutter blade 2 body; at least one cutter blade 2 includes a buffer portion 21 and a support portion 22, with a partition groove 23 formed between the buffer portion 21 and the support portion 22, and the cutting elements 3 are disposed on the buffer portion 21.

[0083] The flexible PDC drill bit disclosed in this embodiment has a cutting element 3 provided in the buffer section 21 for cutting and drilling during the operation of the drill bit. The support section 22 provided behind it is used to provide support force to prevent the buffer section 21 from undergoing elastic deformation and exceeding the set maximum deformation amount, thereby optimizing the rigidity of the entire PDC drill bit and facilitating normal operation when encountering complex environments and high-frequency impact loads.

[0084] The width of the dividing groove 23 is the maximum elastic deformation that the buffer part 21 can undergo. This embodiment optimizes and adopts one feasible option: the width of the dividing groove 23 is 0≤δ≤1mm. When adopting the above scheme, various different deformations can be considered. For example, a dividing groove 23 of equal width can be directly set to limit the deformation of the buffer part 21; or a wider dividing groove 23 can be set, and a corresponding secondary limiting structure can be set in the groove to prevent the buffer part 21 from undergoing excessive deformation, which can also achieve the same deformation limiting effect.

[0085] Preferably, the buffer portion 21 and the support portion 22 form opposing buffer portion partition surfaces 211 and support portion partition surfaces 221, and the space between the two partition surfaces is the partition groove 23.

[0086] The internal structure of the partition groove 23 is optimized as follows: a limiting structure is formed within the partition groove 23, and the limiting structure is connected and fixed to the buffer part 21, or the limiting structure is connected and fixed to the support part 22. When adopting the above scheme, the limiting structure can be integrally formed with the buffer part 21, or separately set and fixed by a connector; or the limiting structure can be integrally formed with the support part 22, or separately set and fixed by a connector.

[0087] Preferably, the limiting structure can be an elastic element, a rolling element, or the like.

[0088] Example 2 This embodiment provides a flexible PDC drill bit. The overall structure is consistent with that in Embodiment 1. The difference in this embodiment is that the layout structure of the partition groove 23 is optimized.

[0089] like Figure 7 , Figure 8 , Figure 9As shown, the partition groove 23 can limit the buffer part 21 in multiple directions in addition to the circumferential tangential direction. This embodiment optimizes this by adopting one feasible option: the partition groove 23 extends radially along the blade 2 to form a straight groove, an arc-shaped groove, or a bent groove. When the above scheme is adopted, the straight groove is used to limit the amount of deformation in the circumferential tangential direction, and the arc-shaped groove and the bent groove can be used to limit the amount of deformation in the circumferential tangential direction and the radial direction. Thus, the relative position of the buffer part 21 and the support part 22 can be kept within a set range during deformation.

[0090] Preferably, the width of the partition groove 23 in this embodiment is 0~1mm. Different groove structures can be used to achieve limiting in different directions, thereby maintaining the relative position stability of the buffer part 21 and the support part 22.

[0091] Example 3 This embodiment provides a flexible PDC drill bit. The overall structure is consistent with that in Embodiment 1, but with certain improvements and optimizations. Specifically, the cooperation structure between the buffer part 21 and the support part 22 is improved.

[0092] like Figures 10-13 As shown, in this embodiment, the circumferential tangential and radial positions of the buffer portion 21 can be limited in various ways. This embodiment optimizes and adopts some feasible options: a constraint structure 25 is formed on the support portion 22, and an extension structure corresponding to the constraint structure 25 is formed on the buffer portion 21. After the extension structure cooperates with the constraint structure 25, a gap is formed, preventing the deformation of the buffer portion 21 in the circumferential tangential direction from exceeding the maximum width of the partition groove 23; and / or, a constraint structure 25 is formed on the support portion 22, and an extension structure corresponding to the constraint structure 25 is formed on the buffer portion 21. After the extension structure cooperates with the constraint structure 25, a gap is formed, preventing the deformation of the buffer portion 21 in the circumferential radial direction from exceeding the maximum width of the partition groove 23. When the above scheme is adopted, the constraint structure 25 can be integrally formed with the support portion 22, or it can be set separately and fixed by connecting fasteners.

[0093] The constraint structure 25 and the extension structure can adopt various schemes, and their structures are not limited to a single one. This embodiment optimizes and adopts one feasible option: the constraint structure 25 is disposed on the front side and / or the upper end surface of the support part 22, and the constraint structure 25 includes a constraint protrusion or a constraint groove. When adopting the above scheme, the constraint structure 25 can be a square or elongated protrusion, or a groove structure of a corresponding shape, while the extension structure is correspondingly matched with the constraint structure 25 to form a snap-fit ​​fit.

[0094] In some schemes, in addition to using the above-mentioned constraint structure 25 and extension structure to achieve positive constraints, the above-mentioned constraint structure 25 and extension structure can also be used to form reverse constraints.

[0095] Example 4 This embodiment provides a flexible PDC drill bit. The overall structure is consistent with that in Embodiment 1. The main improvement in this embodiment is the arrangement of the support part 22.

[0096] like Figures 17-23 , Figures 25-27 As shown, the support portion 22 can be arranged in various forms and is not limited to one specific method. This embodiment optimizes and adopts one feasible option: several support portions 22 are arranged on the rear side of the buffer portion 21, and a partition groove 23 is formed between adjacent support portions 22. When the above scheme is adopted, the multiple partition grooves 23 between the multiple support portions 22 provide a larger elastic deformation space, which can provide more optimized stiffness, provide a more feasible drilling scheme for different complex geological conditions, and make the overall structure of the drill bit more stable and reliable.

[0097] Preferably, the width of the partition groove between adjacent support parts 22 is 0~1mm. When the width of the partition groove 23 is not 0, a certain amount of elastic deformation is allowed, thereby allowing for a larger elastic deformation. When the width of the partition groove 23 is 0, the elastic deformation between multiple support parts 22 is minimal or even nonexistent, but the overall structural rigidity of the multiple support parts 22 is optimized, which can better support the buffer part 21 and achieve better cutting operations.

[0098] Example 5 This embodiment provides a flexible PDC drill bit, with an overall structure consistent with that in Embodiment 1. The main improvement in this embodiment is to the cutting structure.

[0099] like Figures 13-16 As shown, in order to improve the cutting effect, in addition to setting the cutting element 3 on the buffer part 21, the overall structure can also be optimized. This embodiment adopts one feasible option: the support part 22 is provided with an auxiliary cutting element 31. When adopting the above solution, the auxiliary cutting element 31 can adopt a variety of cutting teeth.

[0100] Example 6 This embodiment provides a flexible PDC drill bit. The overall structure is consistent with that in Embodiment 1. The main improvement in this embodiment is the specific arrangement of the buffer part 21 and the support part 22.

[0101] like Figures 2-6 , Figures 14-16As shown, there are multiple ways to arrange the buffer part 21 and the support part 22, and they are not limited to one specific method. This embodiment optimizes and adopts one feasible option: the buffer part 21 and the support part 22 are separate from the cutter wing 2 body and are fixed in shape after being fitted together; or, the buffer part 21 is integrally formed with the cutter wing 2 body, and the support part 22 is separate from the cutter wing 2 body and is fixed in shape after being fitted together; or, the buffer part 21 is separate from the cutter wing 2 body and is fixed in shape after being fitted together, and the support part 22 is integrally formed with the cutter wing 2 body. When adopting the above schemes, when the buffer part 21 and / or the support part 22 are separated from the drill bit body 1, they can be connected and fixed by welding.

[0102] The combination of the buffer part 21 and the support part 22 can adopt more schemes. This embodiment optimizes and adopts one feasible option: the front side of the support part 22 forms a plurality of mounting groove structures, the buffer part 21 is located in the mounting groove structure, and the two sides and the rear side of the buffer part 21 in the cutting direction form a separation groove 23 with the support part 22. When the above scheme is adopted, the mounting groove structure can extend downward from the upper end of the support part 22, or it can extend backward from the front side of the support part 22. When the buffer part 21 is fitted into the mounting groove structure, it is then fastened by a connector.

[0103] Example 7 The foregoing embodiments disclose a structure of a flexible PDC drill bit, and this embodiment provides another structure of a flexible PDC drill bit.

[0104] Specifically, such as Figure 28 As shown, a flexible PDC drill bit includes a drill body 1 and a cutter wing 2, with a plurality of cutting elements 3 formed on the cutter wing 2; it includes at least one flexible cutter wing 2, with an additional structure 24 formed on the rear side of the flexible cutter wing 2, the additional structure 24 being used to support the flexible cutter wing 2 and prevent the elastic deformation of the flexible cutter wing 2 from exceeding the maximum allowable value α.

[0105] The flexible PDC drill bit disclosed in this embodiment provides a flexible blade 2 that can deform during operation. It also provides another support solution, specifically by using an additional structure 24 to support the flexible blade 2, making the flexible blade 2 and the drill bit body 1 more integrated and allowing for greater elastic deformation.

[0106] Example 8 This embodiment provides a flexible PDC drill bit, mainly by improving the configuration of the additional structure 24.

[0107] like Figure 28 , Figures 31-24As shown, the layout extension of the additional structure 24 can adopt various schemes and is not limited to one. This embodiment optimizes and adopts one feasible option: the additional structure 24 extends from the drill body 1 toward the flexible cutter wing 2 or extends from the adjacent cutter wing 2 at the rear toward the flexible cutter wing 2. The additional structure 24 is in contact with the flexible cutter wing 2 or forms a gap. When the additional structure 24 forms a gap with the flexible cutter wing 2, the width of the gap is 0≤α≤1mm. When adopting the above scheme, the additional structure 24 can be a single support structure or multiple support structures.

[0108] The additional structure 24 can be configured in various ways. This embodiment optimizes and adopts one feasible option: the front end of the additional structure 24 is connected to the flexible blade wing 2, and the rear end is integrally formed or connected to the adjacent blade wing 2; or, the front end of the additional structure 24 is separate from the flexible blade wing 2, and the rear end is integrally formed or connected to the adjacent blade wing 2. When adopting the above scheme, adjacent blade wings 2 can be connected sequentially through the additional structure 24, or all blade wings 2 can be divided into several groups, and additional structures 24 can be set in each group for connection.

[0109] Specifically, when fixing the additional structure 24, the following scheme can be adopted: when the additional structure 24 is connected to the flexible blade 2 or the adjacent blade 2 in a connecting and cooperating manner, the connecting and cooperating includes surface contact and connection by fasteners, and also includes hole and shaft connection and connection by anti-retraction component.

[0110] Preferred, such as Figure 35 , Figure 36 As shown, the additional structure 24 includes a support column structure, an elastic body structure, and a rolling body structure.

[0111] Example 9 This embodiment provides a flexible PDC drill bit, which mainly optimizes the structure of the blade 2-body.

[0112] like Figure 29 , Figure 30 As shown, due to the addition of the stiffening structure 24, the structure of the blade wing 2 itself can be optimized. This embodiment adopts one feasible option: the thickness of the flexible blade wing 2 gradually increases with its height, or the thickness at the connection between the flexible blade wing 2 and the drill bit body 1 is a first thickness, and the thickness at the location where the cutting element 3 is set on the flexible blade wing 2 is a second thickness, with the second thickness being greater than the first thickness. When adopting the above scheme, one side of the flexible blade wing 2 is a slope, an arc surface, or a stepped surface.

[0113] Example 10 The above embodiments describe flexible PDC drill bits, and this embodiment also provides a composite drill bit.

[0114] A composite drill bit includes the flexible PDC drill bit described above, wherein the drill bit body 1 is made of composite material; or, a composite cutting structure is provided on the cutter blades 2 of the drill bit body 1; or, a composite hydraulic structure is provided on the drill bit body 1.

[0115] Specifically, when the drill bit body 1 is made of composite materials, it can adopt a matrix composite, using powder metallurgy + liquid phase sintering process to construct multiphase composite materials, and the non-magnetic design can be used for measurement while drilling (MWD); or it can adopt a steel body composite, using a high-strength alloy steel matrix + surface hardening composite strategy, which can be regenerated multiple times after wear by welding and re-tooth arrangement, with obvious advantages in the whole life cycle cost; or it can adopt a steel-matrix composite, which can be regenerated multiple times after wear by welding and re-tooth arrangement, with obvious advantages in the whole life cycle cost.

[0116] When the cutter blades 2 of the drill bit body 1 are equipped with a composite cutting structure, a main-backup tooth composite can be used. During normal drilling, only the main tooth works; when encountering hard interlayers (such as flint nodules) that cause the main tooth to wear or break, the backup tooth automatically takes over the cutting to prevent the drill bit from "losing its bottom". Alternatively, the drill bit body 1 can use a PDC-impregnated diamond composite for multi-mechanism rock breaking in extremely hard and highly abrasive formations (such as granite and quartz sandstone). Alternatively, the drill bit body 1 can use a geometric composite of irregularly shaped teeth, such as combining ridged teeth, conical teeth, axe-shaped teeth, etc., with conventional planar teeth to achieve spatial composite.

[0117] When the power transmission structure of the drill bit body 1 is mechanically combined, it can be set as a PDC-roller cone hybrid drill bit, which utilizes the shearing action of PDC and the crushing / impact action of roller cone to form a synergistic dual rock breaking mechanism; or it can be set as a rotary impact composite mechanism, integrating a high-frequency impactor and a conventional PDC drill bit.

[0118] When the hydraulic structure and flow channel functions are combined on the drill bit body 1, schemes such as jet-flood combination, variable diameter flow channel combination, and adaptive hydraulic adjustment can be set.

[0119] When intelligent and functional expansion are combined on the drill bit body 1, it can be set as a sensor-actuator integrated composite scheme, or a drilling-while-reaming composite scheme, etc.

[0120] To further verify the nonlinear variable stiffness characteristics of the flexible PDC drill bit cutting structure provided by this invention under complex working conditions (especially for instantaneous impact loads downhole), a comparative model of the flexible PDC drill bit described in the above embodiments and the cutter wing of a conventional PDC drill bit was established using the finite element analysis method. Dynamic simulation analysis of the cutter wing under an instantaneous lateral impact load (100,000 N) was performed, and stress response data within 0 to 1 second were extracted, such as... Figures 37-40 As shown.

[0121] Simulation data shows that, due to its continuous structure and constant stiffness, a conventional cutter blade exhibits almost no significant buffering deformation when subjected to lateral impact, with its stress rapidly increasing to approximately 850 MPa and remaining thereafter. In contrast, the cutter blade of the flexible PDC drill bit described in this invention (labeled as flexible cutter blade in the figure) exhibits significant dynamic response characteristics during loading, unloading, and support: In the initial stage of impact, the cutter blade utilizes the gap to generate a slight backward displacement, resulting in significant strain. This strain effectively converts the impact energy into mechanical displacement, significantly reducing the instantaneous stress at this point. Subsequently, it enters the rigid support stage. As the impact continues, the gap closes, the strain increase slows down, and the stress rapidly recovers to 896.3 MPa, indicating that the support effectively provides rigid support reaction force.

[0122] In summary, the flexible PDc drill bit provided by this invention, through the opening and closing mechanism of the gap, enables the drill bit to have variable stiffness characteristics that adapt to the load: when encountering instantaneous impact, it increases the strain displacement for flexible buffering to protect the cutting teeth; after the gap closes, it quickly restores high rigidity to maintain rock breaking efficiency, truly realizing the technical effect of flexible cutting.

[0123] The above are the embodiments listed in this example; however, this example is not limited to the optional embodiments described above; those skilled in the art can arbitrarily combine the above methods to obtain other various embodiments; anyone can derive other various forms of embodiments under the guidance of this example. The above specific embodiments should not be construed as limiting the scope of protection of this example; the scope of protection of this example should be determined by the claims.

Claims

1. A flexible PDC drill bit, comprising a drill bit body (1) and a cutter wing (2) body, wherein a plurality of cutting elements (3) are formed on the cutter wing (2) body; characterized in that: At least one blade (2) includes a buffer section (21) and a support section (22), with a partition groove (23) formed between the buffer section (21) and the support section (22), and the cutting element (3) is disposed on the buffer section (21).

2. The flexible PDC drill bit according to claim 1, characterized in that: The width of the dividing groove (23) is 0≤δ≤1mm.

3. The flexible PDC drill bit according to claim 1, characterized in that: The dividing groove (23) extends radially along the blade (2) to form a straight groove, an arc groove, or a bent groove.

4. The flexible PDC drill bit according to claim 3, characterized in that: A limiting structure is formed in the dividing groove (23), and the limiting structure is connected and fixed to the buffer part (21), or the limiting structure is connected and fixed to the support part (22).

5. The flexible PDC drill bit according to claim 1 or 2, characterized in that: A constraint structure (25) is formed on the support part (22), and an extension structure corresponding to the constraint structure (25) is formed on the buffer part (21). The extension structure and the constraint structure (25) cooperate to form a gap and prevent the deformation of the buffer part (21) in the circumferential tangential direction from exceeding the maximum width of the partition groove (23); and / or, a constraint structure (25) is formed on the support part (22), and an extension structure corresponding to the constraint structure (25) is formed on the buffer part (21). The extension structure and the constraint structure (25) cooperate to form a gap and prevent the deformation of the buffer part (21) in the circumferential radial direction from exceeding the maximum width of the partition groove (23).

6. The flexible PDC drill bit according to claim 5, characterized in that: The constraint structure (25) is disposed on the front side of the support (22) and / or the upper end face of the support (22), and the constraint structure (25) includes a constraint protrusion or a constraint groove.

7. The flexible PDC drill bit according to claim 1 or 2, characterized in that: The rear side of the buffer section (21) is provided with a plurality of support sections (22), and a partition groove (23) is formed between adjacent support sections (22).

8. The flexible PDC drill bit according to claim 1, characterized in that: An auxiliary cutting element (31) is provided on the support part (22).

9. The flexible PDC drill bit according to claim 1, characterized in that: The buffer part (21) and the support part (22) are separated from the blade wing (2) body and fixed after being fitted together; or, the buffer part (21) is integrally formed with the blade wing (2) body, and the support part (22) is separated from the blade wing (2) body and fixed after being fitted together; or, the buffer part (21) is separated from the blade wing (2) body and fixed after being fitted together, and the support part (22) is integrally formed with the blade wing (2) body.

10. The flexible PDC drill bit according to claim 1, characterized in that: The front side of the support (22) forms several mounting groove structures, and the buffer (21) is located in the mounting groove structure. The two sides and the rear side of the buffer (21) in the cutting direction form a partition groove (23) with the support (22).

11. A flexible PDC drill bit, comprising a drill bit body (1) and a cutter wing (2) body, wherein a plurality of cutting elements (3) are formed on the cutter wing (2) body; characterized in that: It includes at least one flexible blade (2), with an additional structure (24) formed on the rear side of the flexible blade (2), the additional structure (24) being used to support the flexible blade (2) and prevent the elastic deformation of the flexible blade (2) from exceeding the maximum allowable value α.

12. The flexible PDC drill bit according to claim 11, characterized in that: The additional structure (24) extends from the drill body (1) toward the flexible blade (2) or from the adjacent blade (2) at the rear toward the flexible blade (2). The additional structure (24) contacts and abuts against the flexible blade (2) or forms a gap. When the additional structure (24) forms a gap with the flexible blade (2), the width of the gap is 0≤α≤1mm.

13. The flexible PDC drill bit according to claim 11, characterized in that: The front end of the additional structure (24) is connected to the flexible blade (2), and the rear end is integrally formed or connected to the adjacent blade (2); or, the front end of the additional structure (24) is separated from the flexible blade (2), and the rear end is integrally formed or connected to the adjacent blade (2).

14. The flexible PDC drill bit according to claim 13, characterized in that: When the additional structure (24) is connected to the flexible blade (2) or adjacent blade (2) in a connecting fit, the connecting fit includes surface contact and connection by fasteners, and also hole-shaft connection and connection by anti-reverse component.

15. The flexible PDC drill bit according to claim 12, characterized in that: The additional structure (24) includes a support column structure, an elastomer structure, and a rolling element structure.

16. The flexible PDC drill bit according to claim 11, characterized in that: The thickness of the flexible blade (2) gradually increases with its height, or the thickness at the connection between the flexible blade (2) and the drill body (1) is the first thickness, and the thickness at the location where the cutting element (3) is set on the flexible blade (2) is the second thickness, which is greater than the first thickness.

17. A composite drill bit, comprising the flexible PDC drill bit according to any one of claims 1 to 10, or comprising the flexible PDC drill bit according to any one of claims 11 to 16; characterized in that, The drill bit body (1) is made of composite material; or, a composite cutting structure is provided on the cutter blade (2) of the drill bit body (1); or, a composite hydraulic structure is provided on the drill bit body (1).

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