Polycrystalline diamond compact and drill bit

Abstract

The present application relates to the field of oil and gas exploration and development drilling tools, and discloses a low-temperature assembly poly-crystal diamond compact, which comprises a hard alloy base and a poly-crystal diamond layer, the poly-crystal diamond layer is arranged at the end of the hard alloy base and forms a cutting surface at the end, and the hard alloy base is composed of a fixed part and a mounting part, the poly-crystal diamond layer is arranged at the end surface of the mounting part, the fixed part and the mounting part are fixedly connected through a concave-convex structure, the concave-convex structure is composed of a convex structure and a concave structure matched with each other, and the convex structure and the concave structure are fixedly connected through the cooperation of elastic pins and corresponding pin holes. The poly-crystal diamond compact is divided into two parts, the mounting part with the poly-crystal diamond layer is mounted on the fixed part through the concave-convex structure, which makes the on-site installation more convenient and avoids the damage of high temperature to the performance of the poly-crystal diamond compact during direct brazing of the poly-crystal diamond compact.

Description

Technical Field

[0001] This invention relates to the field of drilling tools for oil and gas exploration and development, and particularly to a polycrystalline diamond composite sheet and a polycrystalline diamond composite sheet drill bit. Background Technology

[0002] Polycrystalline diamond composite sheets combine the high hardness and wear resistance of diamond with the high impact resistance of cemented carbide, making them a relatively ideal drilling material. Since around the 1980s, polycrystalline diamond composite sheets have been gradually adopted as the main cutting element in oil and gas drilling both domestically and internationally.

[0003] Currently, polycrystalline diamond composite sheets are mostly fixed to PDC drill bit bodies by brazing. Due to the characteristics of this composite material, high-temperature heating can damage the performance of the composite sheet. Furthermore, fixing polycrystalline diamond composite sheets via brazing requires extensive equipment and process control, generally needing to be completed in the factory. Once brazed, polycrystalline diamond composite sheets are difficult to replace, and their performance cannot be flexibly adjusted according to the site's rock type and operational conditions.

[0004] In addition, as the main cutting element of PDC drill bits, the working angle of polycrystalline diamond composite sheets is one of the most important design parameters of PDC drill bits. Polycrystalline diamond composite sheets are fixed to the PDC drill bit body by brazing. At present, the working angle of composite sheets on PDC drill bits is mainly determined by the tooth holes on the drill bit body. Adjusting and optimizing the working angle requires redesigning and manufacturing the drill bit body, which is costly and time-consuming, and is not conducive to the optimization of PDC drill bits. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a polycrystalline diamond composite sheet that can be cold-packed at low temperatures.

[0006] The technical solution adopted by the present invention to solve its technical problem is as follows: it includes a cemented carbide substrate and a polycrystalline diamond layer, wherein the polycrystalline diamond layer is disposed at the end of the cemented carbide substrate and forms a cutting surface at the end. The cemented carbide substrate is composed of a fixing part and a mounting part. The polycrystalline diamond layer is disposed on the end face of the mounting part. The fixing part and the mounting part are fixed together by a concave-convex structure. The concave-convex structure is composed of mutually matching protruding structures and recessed structures. The protruding structures and recessed structures are fixedly connected by elastic pins engaging with corresponding pin holes.

[0007] Furthermore, the elastic pin is disposed on the circumferential direction of the protruding structure, and the pin hole is disposed on the recessed structure, with the positions and sizes of the elastic pin and the pin hole corresponding to each other.

[0008] Furthermore, the elastic pins are arranged in layers along the axial direction of the raised structure, and the diameter of each layer of elastic pins decreases sequentially from the top to the bottom of the raised structure; the corresponding pin holes are also arranged in layers along the axial direction of the recessed structure, and correspond to the position and size of the elastic pins.

[0009] Furthermore, the protruding structure is disposed on the back side of the mounting portion relative to the end face, and the recessed structure is disposed on the fixing portion.

[0010] Furthermore, both the protruding and recessed structures are cylindrical, and the elastic pins and pin holes of each layer are evenly arranged along the circumference of the cylinder.

[0011] Optionally, the end faces of the fixing part and the mounting part that come into contact with each other are provided with interlocking toothed groove structures.

[0012] Preferably, the top of the elastic pin is frustoconical, and the pin hole is frustoconical with a smaller bottom and a larger top.

[0013] Furthermore, the pin hole is an annular groove located on the recessed structure.

[0014] As a further improvement, the cutting surface is divided into at least two cutting regions along the circumferential direction, and at least two of the cutting regions have different angles with respect to the axial direction of the cemented carbide matrix. Polycrystalline diamond composite sheets are typically cylindrical, with the polycrystalline diamond layer located at the cutting end to form the cutting surface. Variations in the angle between the cutting region and the axial direction of the cemented carbide matrix result in variations in the clearance angle. Therefore, setting multiple cutting regions allows for more flexible use of the polycrystalline diamond composite sheet; that is, different installation angles allow different cutting regions of the polycrystalline diamond composite sheet to be located at the working position, thereby obtaining different working angles to meet various needs. The cutting region can be a facet, edge, protrusion, curved surface, or other cutting part shape of the tool.

[0015] In one approach, the cutting area is a cutting edge, which is distributed in a ring around the axis of the cutting surface, dividing the cutting surface into multiple fan-shaped areas.

[0016] Furthermore, the cutting edge is provided with 8 edges, and the included angles between each cutting edge and the axial direction of the cemented carbide matrix are 96°, 93°, 90°, 87°, 84°, 87°, 90°, and 93°, respectively.

[0017] Furthermore, the area between two adjacent cutting edges is a plane or a curved surface. There are eight cutting edges evenly distributed, and the angles between each cutting edge and the axial direction of the cemented carbide matrix are 87°, 103°, 93°, 103°, 96°, 103°, 93°, and 103°, respectively.

[0018] Furthermore, the included angles are distributed in a counterclockwise order.

[0019] Another approach is that the cutting area is a slit, which is distributed in a ring along the outer edge of the cutting area.

[0020] Furthermore, the cut surface is provided with 6 facets, and the included angles between each facet and the axial direction of the cemented carbide substrate are 95°, 100°, 105°, 110°, 105°, and 100°, respectively.

[0021] Furthermore, the included angles are distributed sequentially in a counterclockwise direction. The width of the cross-section in the radial direction is 3 mm.

[0022] Another approach is that the cutting area is a cutting plane, and the angle between the cutting plane and the axial direction of the cemented carbide substrate is 84° to 96°. That is, the angle between the normal of the cutting plane and the axial direction of the cemented carbide substrate is 6°, and the back angle that can be formed by different cutting areas can vary from -6° to +6°.

[0023] Another technical problem to be solved by the present invention is to provide a polycrystalline diamond composite drill bit that can be cold-loaded at low temperatures.

[0024] The technical solution adopted by the present invention to solve its technical problem is: the polycrystalline diamond composite drill bit adopts the aforementioned polycrystalline diamond composite sheet.

[0025] The beneficial effects of this invention are:

[0026] The polycrystalline diamond composite sheet is divided into two parts. The fixing part is brazed to the drill bit, and the mounting part with the polycrystalline diamond layer is installed on the fixing part through a concave-convex structure. This makes on-site installation more convenient and avoids damage to the performance of the polycrystalline diamond composite sheet caused by the high temperature generated when directly brazing the polycrystalline diamond composite sheet. The polycrystalline diamond composite (PCD) cutting teeth can be assembled at low temperatures during PDC drill bit production, or assembly can be delayed. More targeted PCD cutting teeth can be assembled based on the rock type and operating conditions at the drill bit's application site, allowing for rapid and flexible adjustments to the PDC drill bit. For example, PCD cutting teeth with enhanced impact resistance or abrasion resistance can be flexibly assembled, as well as cutting teeth with various cutting structures, such as single-plane cutting teeth, cutting teeth with increased or decreased rake angles, and multi-faceted cutting teeth. Without a tooth groove structure, the PCD cutting teeth can rotate freely circumferentially. When cutting the formation at the bottom of the well, if the cutting teeth have a certain side angle, the formation will generate tangential friction on the composite, driving the PCD cutting teeth to rotate circumferentially. This slows down wear in a specific circumferential area of ​​the PCD cutting teeth, replacing it with wear on the entire circumferential cutting edge, thus extending the service life of the PCD cutting teeth.

[0027] Meanwhile, by setting multiple cutting zones on the cutting surface, the polycrystalline diamond composite drill bit can have different working angles at different angles, without changing the drill bit body design or remanufacturing the drill bit body. By setting different cutting zones of the composite bit as working areas during installation using a concave-convex structure, different working angles can be obtained, thereby adjusting and optimizing the working angle of each cutting unit (polycrystalline diamond composite bit). When using a multi-faceted polycrystalline diamond composite bit, if a groove structure is not set to restrict the circumferential movement of the composite bit, it may not be possible for the multi-faceted polycrystalline diamond composite bit to work in the correct circumferential position. In this case, the groove structure can be used to fix the circumferential position of the polycrystalline diamond composite bit, thereby ensuring that it participates in the cutting of the formation at the correct position. Attached Figure Description

[0028] Figure 1 Schematic diagram of a polycrystalline diamond composite drill bit;

[0029] Figure 2 This is a schematic diagram of the structure of the present invention;

[0030] Figure 3 This is a schematic diagram of the assembled version of the present invention;

[0031] Figure 4 This is a schematic diagram of Example 1;

[0032] Figure 5 These are cross-sectional views of different parts of Example 1;

[0033] Figure 6 This is a schematic diagram of Example 2;

[0034] Figure 7 This is a top view of Embodiment 2;

[0035] Figure 8 for Figure 7 AA-line sectional view;

[0036] Figure 9 for Figure 7 BB line section view;

[0037] Figure 10 for Figure 7 CC-line section view;

[0038] Figure 11 for Figure 7 DD-line sectional view;

[0039] Figure 12 This is a schematic diagram of Example 3;

[0040] Figure 13 This is a top view of Embodiment 3;

[0041] Figure 14 These are cross-sectional views of different parts of Embodiment 3;

[0042] Figure 15 This is a schematic diagram of Example 4;

[0043] Figure 16 This is a half-sectional view of Example 4;

[0044] Figure 17 yes Figure 16 Top view;

[0045] Figure 18 This is a schematic diagram of the cutting process of the present invention;

[0046] Figure 19 This is a schematic diagram of one embodiment of the present invention;

[0047] Figure 20 yes Figure 19 Top view;

[0048] Figure 21 This is a schematic diagram of another embodiment of the present invention;

[0049] Figure 22 yes Figure 21 Top view;

[0050] Figure 23 and Figure 24 This is a schematic diagram of the toothed structure of the present invention;

[0051] Figure 25 This is an enlarged view of the top of the spring pin;

[0052] Figure 26 This is an enlarged view of the pin hole;

[0053] Figure 27 This is a schematic diagram of the working state of one embodiment of the present invention;

[0054] The components, parts and numbers in the figure are as follows: 1. Drill bit, 2. Carbide substrate, 21. Fixing part, 22. Mounting part, 3. Cutting surface, 4. Cutting edge, 5. Polycrystalline diamond layer, 6. Cutting surface, 7. Protruding structure, 8. Recessed structure, 9. Elastic pin, 10. Pin hole, 11. Protrusion, 12. Groove, 13. Detailed Implementation

[0055] The invention will now be further described with reference to the accompanying drawings.

[0056] like Figure 2 and Figure 3As shown, the present invention includes a cemented carbide substrate 2 and a polycrystalline diamond layer 6. The polycrystalline diamond layer 6 is disposed at the end of the cemented carbide substrate 2 and forms a cutting surface 3 at the end. The cemented carbide substrate 2 consists of a fixing part 21 and a mounting part 22. The polycrystalline diamond layer 6 is disposed on the end face of the mounting part 22. The fixing part 21 and the mounting part 22 are fixedly mounted by a concave-convex structure. The concave-convex structure consists of mutually matching protruding structures 8 and recessed structures 9. The protruding structures 8 and recessed structures 9 are fixedly connected by elastic pins 10 and corresponding pin holes 11. The present invention divides the cemented carbide substrate 2 into two parts, the fixing part 21 and the mounting part 22, for the purpose of flexible installation of the cemented carbide substrate 2. The fixing part 21 and the mounting part 22 are mounted by a concave-convex structure 9. One end of the fixing part 21 can be machined into a protruding structure 8, and the corresponding mounting part can be machined into a recessed structure 9; or one end of the fixing part 21 can be machined into a recessed structure 9, and the corresponding mounting part can be machined into a protruding structure 8. The resilient pin 10 is generally composed of a spring and a pin, both installed in the mounting hole, allowing the pin to be pressed down and springed back up. It can be located on the protruding structure 8, with the pin hole 11 located on the recessed structure 9; alternatively, the resilient pin 10 can be located on the recessed structure 9, with the corresponding pin hole 11 located on the protruding structure 8. The shapes of the protruding structure 8 and the recessed structure 9 need to match, and conventional columnar shapes are acceptable, such as square, elliptical, or cylindrical. The corresponding recessed structure 9 also has a corresponding columnar hole shape. The fixing part 21 can be pre-installed on the drill bit 1 by brazing. The polycrystalline diamond layer 6 is cold-installed onto the fixing part 21 along with the mounting part 22, eliminating the need for brazing the polycrystalline diamond layer 6 and avoiding the high temperature of 600-700℃ during brazing, which could affect its performance. More advantageously, the polycrystalline diamond layer 6 can be rotated and mounted onto the fixing part 21 at different angles. When combined with a polycrystalline diamond layer 6 having a variable-angle cutting surface 3, different angles can be selected during installation to obtain different cutting angles and meet different requirements. The specific variable-angle cutting surface 3 is described in the embodiments below.

[0057] As a preferred embodiment, such as Figure 2 As shown, the elastic pin 10 is disposed on the circumferential direction of the protruding structure 8, and the pin hole 11 is disposed on the recessed structure 9. The positions and sizes of the elastic pin 10 and the pin hole 11 correspond to each other. This arrangement makes it more convenient to press the elastic pin 10. When the protruding structure 8 is inserted into the recessed structure 9, the spring pin 10 can be pressed down. When the spring pin 10 reaches the corresponding pin hole 11, it will naturally lock into place and complete the fixation.

[0058] To improve the strength and stability of the assembly, two or more layers of multi-layered elastic pins 10 are provided axially in the protruding structure 8. Figure 2 and 3As shown, the elastic pins 10 are arranged in layers along the axial direction of the protruding structure 8. The number of layers can be set according to the size. Three layers are set in the figure as an example. The diameter of the elastic pins 10 in each layer decreases from the top to the bottom of the protruding structure 8. The corresponding pin holes 11 are also arranged in layers along the axial direction of the recessed structure 9 and correspond to the position and size of the elastic pins 10. Because the elastic pin 10 at the top of the protruding structure 8 is relatively large, while the upper pin hole 11 of the recessed structure 9 is relatively small, the elastic pin 10 at the top of the protruding structure 8 cannot enter the upper pin hole 11 of the recessed structure 9 during insertion. The corresponding pin hole 11 is only available when it is inserted to the bottom of the recessed structure 9. This avoids the elastic pin 10 at the top of the protruding structure 8 from being mistakenly inserted into the upper and middle pin holes 11 of the recessed structure 9. This allows for the setting of multiple layers of elastic pins 10 on the protruding structure 8, improving assembly strength, while eliminating the need for a complex structure to control the pop-out of the elastic pins 10. All the elastic pins 10 will pop out simultaneously when 22 and 21 are assembled in place, completing the assembly and fixing.

[0059] Specifically, such as Figure 2 and Figure 3 As shown, the protruding structure 8 is provided on the back side of the mounting part 22 opposite to the end face, and the recessed structure 9 is provided on the fixing part 21.

[0060] To facilitate adjustment of the installation angle of cutting surface 3, such as Figure 6 As shown, both the protruding structure 8 and the recessed structure 9 are cylindrical, and the elastic pins 10 and pin holes 11 of each layer are evenly arranged along the circumference of the cylinder. The advantage of the cylindrical shape is that it can be rotated arbitrarily during installation, thus obtaining different cutting surface angles 3 of the polycrystalline diamond layer 6. Moreover, this setting can be completed on-site and can fully adapt to different geological conditions.

[0061] In order to ensure that the fixing part 21 and the mounting part 22 can be fixed after installation, such as Figure 23 and 24 As shown, the end faces of the fixing part 21 and the mounting part 22 that come into contact with each other are provided with interlocking toothed groove structures. In the figure, the mounting part 22 has three circumferentially distributed grooves 13, and the fixing part 21 has three circumferentially distributed protrusions 12. Of course, they can also be arranged in reverse. When assembled, the toothed groove structure formed by the protrusions 12 and the grooves 13 can restrict the circumferential rotation of the mounting part 22, and can fix a certain circumferential position of the polycrystalline diamond layer 6 for cutting the formation. The more protrusions 12 and grooves 13 evenly distributed on the fixing part 21 and the mounting part 22, the more precise the circumferential position can be restricted. The cross-sectional shape of the grooves 13 and the protrusions 12 is not limited to rectangles, but can also be trapezoidal, semi-circular, elliptical, etc.

[0062] To ensure a tighter fit between the resilient pin 10 and the pin hole 11, such as... Figure 25and 26 As shown, the top of the elastic pin 10 is frustoconical, and the pin hole 11 is also frustoconical with a smaller bottom and a larger top. Because the pin hole 11 and the top of the elastic pin 10 are tapered, under the spring force F... 弹 Under the action of the pin hole 11, the pin generates two components of force in two directions: axial force F 轴 and radial force F 径 F on each flexible pin 轴 This allows the polycrystalline diamond composite sheet to adhere tightly to the fixing part 22. The axial and radial directions refer to the axial and radial directions of the polycrystalline diamond composite sheet.

[0063] Figure 27 A working method is presented, wherein the pin hole 11 is an annular groove located on the recessed structure 9. In this embodiment, the circumferential movement of the polycrystalline diamond layer 6 is not restricted. When the polycrystalline diamond layer 6 cuts rock, a side tilt angle can be set. While cutting the rock, the polycrystalline diamond layer 6 is subjected to the frictional force of the rock, causing the polycrystalline diamond layer 6 and the mounting part 22 to rotate around the axis of the polycrystalline diamond layer 6. This ensures that the cutting edges at all circumferential positions of the polycrystalline diamond layer 6 participate in the cutting of the rock, thereby delaying localized wear of the polycrystalline diamond layer 6 and replacing it with uniform wear of the entire circumferential cutting edge, thus improving the service life of the composite sheet.

[0064] Figure 27 Implementation methods and Figure 23 and 24 The implementation methods can be used together, in which case the fixing part 21 and the mounting part 22 will be fixed to each other and cannot rotate.

[0065] The operational status diagrams for all embodiments can be found in the reference diagrams. Figure 18 As shown.

[0066] The following embodiments can be used in conjunction with the foregoing implementation methods to fully utilize the flexible on-site cold assembly feature of this invention. By rotating the device at an appropriate angle for installation, different cutting angles can be obtained. Specific methods are described in the following embodiments:

[0067] Example 1

[0068] See Figure 4 and Figure 5 As shown, the cutting area of ​​the polycrystalline diamond layer 6 is the cutting edge 4. The cutting edge 4 is formed at the intersection of two adjacent surfaces. The cutting edges 4 are distributed in a ring around the axis of the cutting surface 3, dividing the cutting surface 3 into multiple fan-shaped areas. There are 8 cutting edges 4. Figure 2 and Figure 3In the counterclockwise direction, the angles between each cutting edge 4 and the axial direction of the cemented carbide substrate (2) are 96°, 93°, 90°, 87°, 84°, 87°, 90°, and 93°, respectively. When welding the composite sheet, placing different edges in the working area will cause the working angle to change. Using a 96° cutting edge will increase the back angle by 6°, a 93° cutting edge will increase the back angle by 3°, and a 90° cutting edge will have the same back angle as the tooth hole design. An 87° cutting edge will decrease the back angle by 3°, and an 84° edge will decrease the back angle by 6°. When welding the composite sheet, placing different faces in the working area will cause the working angle to change. Using the back angle between a 96° edge and a 93° edge can increase the back angle by 3-6°, using the back angle between a 93° edge and a 90° edge can increase the back angle by 0-3°, using the back angle between a 90° edge and an 87° edge can decrease the back angle by 0-3°, and using the back angle between an 87° edge and an 84° edge can decrease the back angle by 3-6°. Angle change markings can be made on the cemented carbide substrate 2 to facilitate angle adjustment during installation.

[0069] Example 2

[0070] See Figures 6 to 11 As shown, the cutting area is the cutting edge 4, which has a certain width. The cutting edges 4 are distributed in a ring around the axis of the cutting surface 3, dividing the cutting surface 3 into multiple fan-shaped areas. The area between two adjacent cutting edges 4 is a plane or curved surface. There are eight cutting edges 4 evenly distributed. In the counter-clockwise direction shown in the figure, the angles between each cutting edge 4 and the axis of the cemented carbide substrate 2 are 87°, 103°, 93°, 103°, 96°, 103°, 93°, and 103°, respectively. The polycrystalline diamond layer of the composite sheet has eight cutting edges 4 with different angles. The area between each cutting edge 4 is a plane or curved surface. The angles between each cutting edge 4 and the axis of the composite sheet are shown in the cross-section. Figure 6 As shown, using an 87° cutting edge 4 can reduce the back angle by 3°, using a 93° cutting edge 4 can increase the back angle by 3°, using a 96° cutting edge 4 can increase the back angle by 6°, and using a 105° cutting edge can increase the back angle by 15°.

[0071] Example 3

[0072] See Figure 12 , Figure 13 , Figure 14As shown, the cutting area is a sectional surface 7, which is distributed in a ring along the outer edge of the cutting area. There are six sectional surfaces 7, and the angles between each sectional surface 7 and the axial direction of the cemented carbide substrate 2 are 95°, 100°, 105°, 110°, 105°, and 100°, respectively. These angles are distributed counterclockwise. The radial width of each sectional surface 7 is 3 mm. The polycrystalline diamond layer 6 has six sectional surfaces 7 that form angles with the axis of the cemented carbide substrate 2 in different directions. The sectional surfaces 7 intersect the cutting surface 3 of the polycrystalline diamond layer 6 at a rotation axis 5. The rotation axis 5 is 3 mm away from the edge of the polycrystalline diamond layer 6. This allows for a greater range of angles while maintaining the same thickness of the polycrystalline diamond layer 6. In this example, the increased back angles of the six sectional surfaces are 5°, 10°, 15°, and 20°, respectively.

[0073] Example 4

[0074] like Figure 15 , Figure 16 , Figure 17 As shown, the cutting area is a cutting plane, and the angle between the normal of the cutting plane and the axial direction of the cemented carbide substrate 2 is 6°. A virtual plane passing through and rotating around the axis of the cemented carbide substrate 2 can form numerous intersections with the cutting plane, with angles between these intersections and the axis of the cemented carbide substrate 2 ranging from 84° to 96°. The end face of the polycrystalline diamond layer 6 is also a cutting plane, but its direction is not parallel to the axial direction of the cemented carbide substrate 2. By using its different circumferential positions, different back angle variations can be obtained, such as... Figure 11 As shown, the angle between the end face normal of the polycrystalline diamond layer 2 and the axis of the cemented carbide substrate 2 is 6°, but it is not limited to this angle. For example... Figure 12 As shown, when cutting the formation using the area at point a, the back angle can be reduced by 6°; when cutting using the area at point b, the back angle changes to zero; when cutting using the area at point c, the back angle increases by 6°; when using the circumferential position between points a and b, the back angle changes from a decrease of 6° to a decrease of 0° from point a to point b; when using the circumferential position between points b and c, the back angle changes from an increase of 0° to an increase of 6° from point b to point c.

Claims

1. A polycrystalline diamond composite sheet, comprising a cemented carbide substrate (2) and a polycrystalline diamond layer (6), wherein the polycrystalline diamond layer (6) is disposed at an end of the cemented carbide substrate (2) and forms a cutting surface (3) at the end, characterized in that: The hard alloy substrate (2) consists of two parts: a fixing part (21) and a mounting part (22). The polycrystalline diamond layer (6) is disposed on the end face of the mounting part (22). The fixing part (21) and the mounting part (22) are fixed together by a concave-convex structure. The concave-convex structure consists of a matching protruding structure (8) and a recessed structure (9). The protruding structure (8) and the recessed structure (9) are fixedly connected by the cooperation of an elastic pin (10) with the corresponding pin hole (11). The elastic pin (10) is disposed on the circumferential direction of the protruding structure (8), and the pin hole (11) is disposed on the recessed structure (9). The positions and sizes of the elastic pin (10) and the pin hole (11) correspond to each other. The elastic pins (10) are arranged in layers along the axial direction of the protruding structure (8), and the diameter of each layer of elastic pins (10) decreases sequentially from the top to the bottom of the protruding structure (8); the corresponding pin holes (11) are also arranged in layers along the axial direction of the recessed structure (9), and correspond to the position and size of the elastic pins (10). Both the protruding structure (8) and the recessed structure (9) are cylindrical, and the elastic pins (10) and pin holes (11) of each layer are evenly arranged along the circumference of the cylinder. The cutting surface (3) is divided into at least two cutting regions along the circumferential direction, and at least two cutting regions have different angles with the axial direction of the cemented carbide matrix (2).

2. The polycrystalline diamond composite sheet as described in claim 1, characterized in that: The protruding structure (8) is provided on the back side of the mounting part (22) relative to the end face, and the recessed structure (9) is provided on the fixing part (21).

3. The polycrystalline diamond composite sheet as described in claim 1, characterized in that: The fixing part (21) and the mounting part (22) are provided with interlocking tooth groove structures on their contacting end faces.

4. The polycrystalline diamond composite sheet as described in claim 1, characterized in that: The top of the elastic pin (10) is frustoconical, and the pin hole (11) is frustoconical with a small bottom and a large top.

5. The polycrystalline diamond composite sheet as described in claim 1, characterized in that: The cutting area is the cutting edge (4), which is distributed in a ring around the axis of the cutting surface (3) and divides the cutting surface (3) into multiple fan-shaped areas.

6. The polycrystalline diamond composite sheet as described in claim 5, characterized in that: The cutting edge (4) is provided with 8 edges, and the included angles between each cutting edge (4) and the axial direction of the cemented carbide substrate (2) are 96°, 93°, 90°, 87°, 84°, 87°, 90°, and 93°, respectively.

7. The polycrystalline diamond composite sheet as described in claim 5, characterized in that: The area between two adjacent cutting edges (4) is a plane or a curved surface. There are 8 cutting edges (4) evenly distributed. The angles between each cutting edge (4) and the axial direction of the cemented carbide substrate (2) are 87°, 103°, 93°, 103°, 96°, 103°, 93°, and 103°, respectively.

8. The polycrystalline diamond composite sheet as described in claim 6, characterized in that: The included angles are distributed in a counterclockwise direction.

9. The polycrystalline diamond composite sheet as described in claim 1, characterized in that: The cutting area is a cutting surface (7), which is distributed in a ring along the outer edge of the cutting area.

10. The polycrystalline diamond composite sheet as described in claim 9, characterized in that: The cut surface (7) is provided in 6 ways, and the included angles between each cut surface (7) and the axial direction of the cemented carbide substrate (2) are 95°, 100°, 105°, 110°, 105° and 100° respectively.

11. The polycrystalline diamond composite sheet as described in claim 9, characterized in that: The included angles are distributed in a counterclockwise direction; the width of the cut surface (7) in the radial direction is 3mm.

12. The polycrystalline diamond composite sheet as described in claim 1, characterized in that: The cutting area is a cutting plane, and the angle between the cutting plane and the axial direction of the cemented carbide substrate (2) is 84° to 96°.

13. A polycrystalline diamond composite drill bit, characterized in that: The polycrystalline diamond composite sheet as described in any one of claims 1 to 12 is used.

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