Cutting teeth and drill bits

Abstract

The present invention provides a cutting tooth and a drill bit. The cutting tooth includes a cylindrical matrix, with a superhard layer combined on the upper part. The top surface of the superhard layer has a working surface, the edge of the working surface is connected to a chamfered surface, and the other side of the chamfer is the side surface of the superhard layer. There are a plurality of pits on the working surface, the chamfered surface and the side surface of the superhard layer. The superhard layer is made of a super anti-abrasive material. The super anti-abrasive material can be polycrystalline diamond. The pits arranged on the working surface can reduce the contact friction between the rock and the cutting tooth. Therefore, the heat generated when cutting the formation rock on the superhard layer can be reduced, thereby reducing the thermal damage of the superhard layer. In this way, the service life of the cutting tooth can be improved.

Description

Technical Field

[0001] The present invention relates to cutting teeth in the field of drill bits for oil exploration and drilling, and more particularly to a cutting tooth and a drill bit. Background Art

[0002] When extracting oil and gas resources during drilling or for other applications, the conventional practice is to connect a drill bit to the lower end of a drill pipe section to form a drill string. By rotating the drill string from the surface, the drill bit interacts with the formation, causing the drill bit to penetrate the formation through grinding, crushing, or shearing actions and reach the target area via a predetermined trajectory. Many different types of drill bits have been developed to drill the wells described above.

[0003] The cutting teeth on the drill bit blades are typically made of hard materials. In a typical drill bit, each cutting tooth includes an elongated and generally cylindrical tungsten carbide substrate that is fixed in a groove on a blade surface. Conventional cutting teeth usually also include a superhard layer made of polycrystalline diamond (hereinafter referred to as "PCD") or other anti-abrasive materials (such as thermally stable diamond or polycrystalline cubic boron nitride).

[0004] One factor determining the life of a PCD cutting tooth is the time the cutting tooth is exposed to a thermal environment. When the temperature of the diamond layer is between 700 - 750 degrees Celsius, polycrystalline diamond is stable. Temperatures above this range can cause damage and structural failure of the polycrystalline diamond. This disadvantage of polycrystalline diamond may be due to the large difference in the thermal expansion coefficient between the bonding material cobalt and diamond. After heating the polycrystalline diamond, cobalt and the diamond lattice expand at different rates, causing cracks in the diamond lattice structure and ultimately leading to the deterioration of the polycrystalline diamond. Damage may also be caused by the reverse transformation between diamond particles to form graphite, resulting in the destruction of the microstructure integrity and the loss of strength under extremely high temperature conditions.

[0005] Due to the friction between the PCD cutting tooth and the rock being cut, heat is generated at the cutting tooth contact point, especially at the exposed part of the PCD layer, which can cause thermal damage to the diamond superhard layer and ultimately lead to (due to the difference in thermal expansion coefficients) the peeling of the polycrystalline diamond superhard layer, the separation of the polycrystalline diamond superhard layer from the substrate, and the transformation of diamond into graphite, resulting in rapid wear. After the cutting tooth has cut the formation for a period of time, the continuous failure of the polycrystalline diamond material will generate a wear surface near the contact point and a lot of frictional heat. As the cutting tooth continues to be used, the size of the wear surface will increase and further generate frictional heat. Due to the above-mentioned thermal expansion mismatch between the diamond and the catalyst, heat may accumulate and cause the cutting tooth to fail.

[0006] Therefore, it is necessary to develop a PCD cutting tooth to provide better thermal stability performance. Compared with conventional PCD cutting teeth, the frictional force during cutting is reduced and the heat conduction is improved, thereby increasing the service life of the cutting tooth. Further, such PCD cutting teeth are required to have the advantages of being simple, easy to manufacture, and low in cost. Summary of the Invention

[0007] The main object of the present invention is to provide a cutting tooth and a drill bit to solve the problems of easy wear and short durability of the drill bit in the prior art under high-temperature environments.

[0008] According to one aspect of the present invention, there is provided a cutting tooth, comprising: a cylindrical substrate; a superhard layer fixed on the substrate; a working surface at the top of the superhard layer; a chamfer provided between the edge of the working surface and the circumferential side surface of the superhard layer; the chamfer surface is connected to the side surface of the superhard layer on the side away from the working surface, wherein a plurality of pits are provided on the working surface, the chamfer surface, and the side surface of the superhard layer.

[0009] Further, the working surface is a flat surface or a non-flat surface.

[0010] Further, the shape of the pit is hemispherical, elliptical, square, or rectangular.

[0011] Further, the plurality of pits are symmetrically distributed about the center on the working surface.

[0012] Further, the plurality of pits are evenly distributed on the working surface.

[0013] Further, the plurality of pits are radially distributed on the working surface.

[0014] Further, the angle of the chamfer is between 30 degrees and 60 degrees.

[0015] Further, the superhard layer is made of polycrystalline diamond.

[0016] Further, a second pit is further provided in the pit.

[0017] Further, a mutually connected channel is provided between two adjacent pits.

[0018] According to another aspect of the present invention, there is provided a drill bit, comprising a plurality of cutting teeth, and the cutting teeth are the above-mentioned cutting teeth.

[0019] Embodiments of the present disclosure are cutting teeth having surface features for reducing the contact friction between the cuttings and the tool surface. The shape, size, and depth of the surface features can vary.

[0020] In the disclosed embodiments, the cutting tooth includes a cylindrical substrate, a superhard layer fixed on the substrate, a working surface at the top of the superhard layer, and a plurality of pits on the working surface.

[0021] In some embodiments, the shape of the pits is hemispherical, elliptical, square or rectangular. The distribution of the pits can be regular or random. In one embodiment, the pits can be evenly distributed across the entire working surface or radially distributed along the radial direction.

[0022] In some embodiments, the superhard layer has a working surface and at least one side surface, and a chamfered surface is formed therebetween. In one embodiment, the working surface is non-planar. In one embodiment, the working surface is planar. In one embodiment, the angle between the surface and the chamfered surface is between 30 and 60 degrees. In one embodiment, the angle between the side surface and the chamfered surface is approximately 45 degrees.

[0023] In some embodiments, the superhard layer is made of a super abrasion-resistant material. In one embodiment, the super abrasion-resistant material can be PCD.

[0024] An embodiment of the present disclosure is a cutting tooth, which includes a cylindrical substrate; a superhard layer fixed on the substrate; a working surface at the top of the superhard layer; and a plurality of pits on the working surface. In one embodiment, the working surface is planar. In one embodiment, the working surface is non-planar. In one embodiment, the shape of the plurality of pits is hemispherical. In one embodiment, the shape of the plurality of pits is elliptical. In one embodiment, the shape of the plurality of pits is square or rectangular. In one embodiment, the distribution of the plurality of pits on the working surface is regular. In one embodiment, the distribution of the plurality of pits on the working surface is random. In one embodiment, the plurality of pits are evenly distributed across the entire working surface. In one embodiment, the plurality of pits are radially distributed across the entire working surface in a divergent manner. In one embodiment, the cutting tooth further includes a side surface and a chamfered surface formed therebetween and the working surface. In one embodiment, the angle between the side surface and the chamfered surface is between 30 and 60 degrees. In one embodiment, the angle between the side surface and the chamfered surface is 45 degrees. In one embodiment, the superhard layer is made of a super abrasion-resistant material. In one embodiment, the super abrasion-resistant material is polycrystalline diamond.

[0025] In some preferred embodiments, at least one minute pit is included in the plurality of pits on the cutting tooth. In some other preferred embodiments, the cutting tooth includes at least one channel connecting adjacent pits to each other.

[0026] The foregoing has outlined rather broadly the features of the present disclosure in order that the detailed description that follows may be better understood. Other features and advantages of the present disclosure will form the subject matter of the claims to be described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To obtain the above-described and other advantages and functions of the present invention, a more specific description will be presented on the basis of the above brief description of the present invention by referring to specific embodiments of the present invention shown in the accompanying drawings. It should be understood that these drawings only depict typical embodiments of the present invention and are therefore not considered to limit its scope. The present invention will be described with additional particularity and detail by using the drawings, wherein:

[0028] Figure 1 is a schematic structural diagram of a drill bit with cutting teeth of the present invention;

[0029] Figure 2 is a schematic diagram of a cutting tooth in the prior art;

[0030] Figure 3 is a schematic diagram of a cutting tooth according to an embodiment;

[0031] Figure 4 is a schematic diagram of a cutting tooth having a pit on the working surface, the density of which is higher than that Figure 3 distributed on the working surface;

[0032] Figure 5 is a schematic diagram of a cutting tooth having a non-planar working surface with circular pits;

[0033] Figure 6 is a schematic diagram of a cutting tooth having elliptical pits;

[0034] Figure 7 is a schematic diagram of a cutting tooth having square / rectangular pits;

[0035] Figure 8 is a schematic diagram of a cutting tooth having pits with small pits;

[0036] Figure 9 is a schematic diagram of a cutting tooth having interconnected pits;

[0037] Figure 10 is a schematic diagram of a cutting tooth having pits on the chamfered surface;

[0038] Figure 11 is a schematic diagram of a cutting tooth having pits on the side of the superhard layer; and

[0039] Figure 12 is a diagram showing the cuttings cut by the cutting teeth.

[0040] Among them, the above-mentioned drawings include the following reference numerals:

[0041] 3, drill bit body; 4, blade; 5, cutting tooth; 502, superhard layer; 503, working surface; 504, substrate; 507, chamfered surface; 510, pit; 520, second pit; 531, channel; 410, formation. Detailed implementation mode

[0042] The details shown herein are only for illustrative purposes and for an illustrative discussion of the preferred embodiments of the present invention, and are disclosed for reasons such as being considered the most useful and easily understandable description of the principles and concepts of various embodiments of the present invention. In this regard, no more detailed information has been disclosed to show the structural details of the present invention except for the information necessary for the basic understanding of the present invention. The description in the accompanying drawings shows several forms of how to implement the present invention in practice to those skilled in the art.

[0043] Specifically, the present invention aims to solve the problems that the drill bit in the prior art is prone to wear and not durable in high-temperature environments.

[0044] Referring to Figure 1 , the drill bit includes a drill bit body 3 and a plurality of cutter wings 4. The cutter wings protrude radially outward from the drill bit body 3 and form a fluid flow channel therebetween. The cutting teeth 5 are grouped and mounted on the cutter wings 4 in radially extending rows. The arrangement or configuration of the cutting teeth 5 on the cutter wings 4 can vary greatly according to different application formations. Referring to Figure 2 , an exemplary cutting tooth 5 includes a PCD superhard layer 502 and a cemented carbide substrate 504. The upper part of the PCD superhard layer 502 has a working surface 503, and may include a chamfered surface 507 formed on the working surface 503 and the side surface of the superhard layer 502, which can also be used as a working surface in contact with the formation during drilling. As Figure 2 shown, flat-top cutting teeth are usually the most common and can be easily manufactured according to known techniques. In one embodiment, the working surface is non-planar. In one embodiment, the working surface is planar.

[0045] Figure 3 Shows a cutting tooth 5 according to an embodiment of the present invention. The cutting tooth 5 is substantially cylindrical. It includes a superhard layer 502 attached to the substrate 504. The process for manufacturing the cutting tooth 5 can use sintered tungsten carbide as the substrate 504, with tungsten carbide particles bonded together with cobalt. A layer of superhard material particles, such as diamond or cubic boron nitride particles, is placed on top of the cemented carbide body, and the encapsulated composition is subjected to a thermodynamically stable pressure at high temperature. This causes the diamond to recrystallize and form a polycrystalline superhard material layer (superhard layer 502), such as a polycrystalline diamond or polycrystalline cubic boron nitride layer, directly attached above the cemented carbide tungsten carbide substrate 504. The superhard layer 502 has a working surface 503 and at least one side surface and a chamfered surface 507 formed therebetween. The angle between the side surface of the superhard layer 502 and the chamfered surface is approximately 45 degrees. In one embodiment, this angle is between 30 and 60 degrees. At least a part of the chamfered surface 507 can also be used as a working surface.

[0046] To reduce the contact friction between the chip and the tool surface, the cutting tooth 5 is provided with a plurality of pits 510 on the working surface 503. These pits 510 help to further break up the rock chips generated when the cutting tooth 5 cuts the rock, thereby reducing the contact time and area between the rock chips and the cutting tooth, reducing the heat generated by friction between the chip and the working surface 503, and significantly reducing the thermal damage of the superhard layer 502. This can extend the service life of the cutting tooth. Figure 3 The pits 510 therein are hemispherical and are evenly distributed on the working surface 503. The radius of the pits can vary.

[0047] Obviously, Figure 3 the design of the shown pits 510 is for illustration only. In actual situations, various shapes, sizes, and pit arrangements can be formed on the working surface 503 according to requirements. For example, Figure 4 shows the pits 510 on the working surface. The working surface 503 is more densely distributed than Figure 3 the working surface 503 therein. Figure 5 shows a non-planar working surface 503 (partially spherical concave surface) with circular pits 510. Figure 6 shows that the shape of the pits 510 is elliptical. Figure 7 shows that the shape of the pits 510 is square or rectangular. The distribution of the pits 510 can be regular or random. The pits 510 can be evenly distributed over the entire working surface 503 as shown in Figure 5 or distributed radially along a radial pattern as shown in Figure 7 .

[0048] As those skilled in the art will recognize, there are other cutting tooth designs according to the features of the present invention. In a preferred embodiment, referring to Figure 8 , a cutting tooth with a pitted surface is shown. The cutting tooth 5 has a substrate 504 and a superhard layer 502 thereon. The chamfered surface extends from the periphery of the working surface 503 to the side wall of the superhard layer 502. The working surface 503 of the superhard layer 502 has a plurality of pits 510 of one size. At least one small second pit 520 having another size smaller than the first size is located on the inner surface of at least one of the pits 510. The small second pits 520 can further reduce the contact friction between the chip and the tool. Although only one small second pit 520 is shown at the bottom of the pit 510, those skilled in the art can easily understand that a plurality of pits 510 can have a plurality of small second pits 520 located therein.

[0049] In another preferred embodiment, referring to Figure 9Disclosed is a cutting tooth with pits. The cutting tooth 5 has a matrix 504 and a superhard layer 502 attached to the upper part. The chamfered surface 507 extends from the periphery of the working surface 503 to the side surface of the superhard layer 502. The working surface 503 of the superhard layer 502 has a plurality of pits 510. A plurality of channels 531 in the superhard layer 502 interconnect adjacent pits with each other, and Figure 8 at least one opening of the channel 531 in the pit 510 is shown. Those skilled in the art will understand that the pit 510 can have a plurality of openings with corresponding channels to connect with adjacent pits. Drilling fluid can flow in the channels 531 and cool the superhard layer 502 to improve the cooling effect of the cutting tooth.

[0050] In another preferred embodiment, referring to Figure 10 , a cutting tooth 5 with pits is shown. The cutting tooth 5 has a matrix 504 and a superhard layer 502 placed thereon. The chamfered surface 507 extends from the periphery of the working surface 503 to the side surface of the superhard layer 502. The working surface 503 of the superhard layer 502 has a plurality of pits 510. A plurality of pits are located on the chamfered surface 507 in the superhard layer 502. Their function is similar to that of the pits 510 on the working surface 503. In some embodiments, the pits are smaller than the size of the pits 510.

[0051] In another preferred embodiment, referring to Figure 11 , a cutting tooth 5 with pits is shown. The cutting tooth 5 has a matrix 504 and a superhard layer 502 placed thereon. The chamfered surface 507 extends from the periphery of the working surface 503 to the side surface of the superhard layer 502. The working surface 503 of the superhard layer 502 has a plurality of pits 510. The pits are arranged on the chamfered surface 507 in the superhard layer 502. The pits located on the side surface of the superhard layer 502 have a function similar to that of the pits 510 on the working surface 503. In some embodiments, the pits on the side surface of the superhard layer 502 are smaller than the size of the pits 510 on the working surface 503.

[0052] Referring to Figure 12 , the cutting tooth 5 cuts the formation 410 through the working surface 503. The surface pits can reduce the contact friction between the rock and the cutting tooth 5. Therefore, the heat on the superhard layer 502 can be reduced, and the thermal damage to the superhard layer 502 can be reduced, ultimately improving the service life of the cutting tooth. Moreover, reducing friction means a smaller lifting force F1 and a smaller pressing force F2 to balance the lifting force F1. This means that a smaller drilling pressure is required to maintain the same cutting depth, less heat is generated, and the rock-breaking process is more efficient.

[0053] In some embodiments, the present invention also provides a drill bit, which includes the above-mentioned cutting tooth with pits.

[0054] All of the compositions and methods disclosed and claimed herein can be made and executed without undue experimentation in accordance with the present invention. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and methods and to the steps or the order of the steps of the methods described herein without departing from the concept, spirit, and scope thereof.

[0055] More specifically, it will be apparent that certain agents described herein can be replaced with related agents while achieving the same or similar results. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept defined by the appended claims.

Claims

1. A cutting tooth, characterized in that, Comprising: A cylindrical substrate; A superhard layer fixed on the substrate; There is a working surface at the top of the superhard layer; A chamfer is provided between the edge of the working surface and the circumferential side surface of the superhard layer; One side of the chamfer surface away from the working surface is connected to the side surface of the superhard layer, Wherein, a plurality of pits are provided on the working surface, the chamfer surface and the side surface of the superhard layer; A second pit is further provided in a plurality of the pits for reducing the contact friction between the rock debris and the cutting tooth; A channel connecting each other is provided between two adjacent pits; The second pit is located at the bottom of the pit; The pits on the side surface of the superhard layer are smaller in size than the pits on the working surface.

2. The cutting tooth according to claim 1, wherein The working surface is a plane or a non-plane.

3. The cutting tooth according to claim 1, wherein The shape of the pit is hemispherical, elliptical, square or rectangular.

4. The cutting tooth according to claim 1, characterized in that, A plurality of the pits are symmetrically distributed about the center on the working surface.

5. The cutting tooth according to claim 1, characterized in that, A plurality of the pits are evenly distributed on the working surface.

6. The cutting tooth according to claim 1, characterized in that, A plurality of the pits are radially distributed on the working surface.

7. The cutting tooth according to claim 1, wherein The angle of the chamfer is between 30 degrees and 60 degrees.

8. The cutting tooth according to claim 1, wherein, The superhard layer is made of polycrystalline diamond.

9. A drill bit includes a plurality of cutting teeth, characterized in that, The cutting tooth is the cutting tooth according to any one of claims 1 to 8.

Images