CN114763734A - Cutting element and drill bit - Google Patents

Abstract

The invention provides a cutting element and a drill bit. The cutting element includes: the substrate is cylindrical; the superhard material layer is fixed on the cylindrical substrate, the top of the superhard material layer is provided with a working surface, and a chamfer angle is formed between the outer side surface of the superhard material layer and the working surface; the cutting teeth are formed at the periphery of the superhard material layer in a cutting mode, so that the orthographic projection of the cutting teeth on the substrate is positioned in the excircle of the projection surface of the substrate; and the cutting ridges are positioned on the working surface and correspond to the cutting teeth one by one. The invention solves the problems that the cutting element of the drill bit in the prior art has low cutting efficiency and can not break chips.

Description

Cutting element and drill bit

Technical Field

The invention relates to the technical field of oil exploration, in particular to a cutting element and a drill bit.

Background

In order to drill a borehole for the production of hydrocarbons or other applications, it is conventional practice to connect a drill bit to the lower end of a drill string section, the drill string section being connected at its trailing end to a trailing end to form a drill string. The drill bit is rotated by rotating the surface drill string to engage the formation, thereby causing the drill bit to cut through the formation material by abrasion, fracturing or shearing action to form a borehole along a predetermined trajectory toward a formation of interest. Many different types of drill bits have been developed and found to be useful in drilling such wellbores.

The cutting elements arranged on the blades of the drill bit are typically formed of an extremely hard material. In a typical drill bit, each cutting element comprises a length of generally cylindrical tungsten carbide substrate that may be received and secured within a recess formed in the surface of a blade. Conventional cutting elements typically include a layer of polycrystalline diamond (PCD) superhard material or other super abrasive substances such as thermally stable diamond or polycrystalline cubic boron nitride.

Cutting elements capable of withstanding high loads during drilling to extend the operational life of the drill bit are desirable. It would also be desirable for a cutter to be able to cut efficiently at designed speeds and load conditions and to control contact area in varying formations. In addition, cutting elements with chip breaking features are also desirable.

As can be seen from the above, the conventional drill has a problem that the cutting element of the drill has low cutting efficiency and cannot break chips.

Disclosure of Invention

The invention mainly aims to provide a cutting element and a drill bit, and aims to solve the problems that the cutting element of the drill bit in the prior art is low in cutting efficiency and cannot break chips.

In order to achieve the above object, according to one aspect of the present invention, there is provided a cutting element comprising: the substrate is cylindrical; the superhard material layer is fixed on the substrate, the top of the superhard material layer is provided with a working surface, and a chamfer angle is formed between the outer side surface of the superhard material layer and the working surface; the cutting teeth are formed at the periphery of the superhard material layer in a cutting mode, so that the orthographic projection of the cutting teeth on the substrate is positioned in the excircle of the projection surface of the substrate; and the cutting ridges are positioned on the working surface and correspond to the cutting teeth one by one.

Further, the periphery of the superhard material layer is provided with a plurality of concave areas, and a cutting tooth is arranged between every two adjacent concave areas.

Further, a plurality of recessed regions are arranged at intervals along the circumferential direction of the superhard material layer, and the recessed regions extend downward along the height direction of the superhard material layer.

Further, the cutting teeth are rounded, pointed or serrated.

Further, the number of the cutting teeth is 1 to 20.

Further, a plurality of recessed regions form the outer boundary of the superhard material layer, the recessed regions originating at the working face, extending in a direction perpendicular to the working face and tapering to an outer side of the substrate.

Further, an angle between the outer side face of the superhard material layer and the chamfer is 30 to 60 degrees.

Further, the working surface is a curved surface.

Further, the working face includes a plurality of area faces, the number of area faces being equal to the number of recessed areas.

Further, the center of the working surface is higher, lower or equal to the edge of the working surface.

Further, the cutting ridges include first ridges located between adjacent two of the land surfaces.

Further, the first ridge is a straight line or a curved line, and the first ridge connects the center of the working surface and the symmetrical center of the cutting tooth.

Furthermore, two adjacent area surfaces are both plane or curved surface structures.

Further, the included angle between two adjacent area surfaces intersecting with the first ridge is 100 degrees to 179.5 degrees.

Further, the cutting ridges further include second ridges located on the land surface between adjacent two of the first ridges.

Further, the second ridge is a straight line or a curved line, and the second ridge connects the center of the working surface and the symmetrical center of the adjacent cutting tooth.

Further, the included angle of two adjacent area surfaces intersecting with the second ridge is 180.5 degrees to 260 degrees.

Further, the radius of the cutting teeth is 10% to 100% of the radius of the cutting element.

According to another aspect of the present invention, there is provided a drill bit including the cutting element described above.

By applying the technical scheme of the invention, the cutting element comprises a substrate, an ultra-hard material layer, cutting teeth and a cutting ridge, wherein the ultra-hard material layer is fixed on the cylindrical substrate, the substrate is cylindrical, the top of the ultra-hard material layer is provided with a working surface, a chamfer is formed between the outer side surface of the ultra-hard material layer and the working surface, the number of the cutting teeth is at least one, the cutting teeth are formed at the periphery of the ultra-hard material layer in a cutting mode, so that the orthographic projection of the cutting teeth on the substrate is positioned in the excircle of the projection surface of the substrate, and the cutting ridges are positioned on the working surface and correspond to the cutting teeth one by one, so that the cutting element can resist high load in a drilling process and has a chip breaking function, and the problems that the cutting efficiency of the cutting element of a drill bit is low and chips cannot be broken in the prior art are solved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 shows a perspective view of a drill bit in one embodiment of the present invention;

FIG. 2 illustrates a perspective view of a conventional cutting element;

FIG. 3 illustrates a schematic view of a conventional cutting element cutting rock;

FIG. 4 illustrates a schematic view of the cutting element of FIG. 3 producing rock debris;

FIG. 5 illustrates a perspective view of a cutting element in an exemplary embodiment of the invention;

FIG. 6 shows a top view of FIG. 5;

FIG. 7 shows a front view of FIG. 5;

FIG. 8 illustrates an angled cross-sectional view of the cutting element of FIG. 5;

FIG. 9 illustrates a cross-sectional view of another angle of the cutting element of FIG. 5;

FIG. 10 shows a schematic view of a cutting element cutting rock in one embodiment of the invention;

fig. 11 shows a schematic view of the cutting element of fig. 8 producing and breaking rock chips.

Wherein the figures include the following reference numerals:

3. a drill bit body; 4. a blade; 5. a cutting element; 502. a layer of superhard material; 503. a working surface; 504. a substrate; 505. an outer side surface; 507. chamfering; 516. cutting teeth; 517. a recessed region; 523. a region surface; 530. a first ridge; 534. a second ridge; 410. an earth formation; 412. a contact surface; 413. and cutting rock debris.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

It is to be noted that, unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

In the present invention, unless specified to the contrary, use of the terms of orientation such as "upper, lower, top, bottom" or the like, generally refer to the orientation as shown in the drawings, or to the component itself in a vertical, perpendicular, or gravitational orientation; likewise, for ease of understanding and description, "inner and outer" refer to the inner and outer relative to the profile of the components themselves, but the above directional words are not intended to limit the invention.

It is to be understood that the above-described embodiments are only a few, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a cutting element and a drill bit, and aims to solve the problems that the cutting element of the drill bit in the prior art is low in cutting efficiency and cannot break chips. Specifically, the drill bit described below includes the cutting elements described below.

As shown in fig. 1, the drill includes a drill body 3 and a plurality of blades 4. A plurality of blades 4 project radially outward from the bit body 3, forming flow passages therebetween. The cutting elements 5 are mounted in groups on the blades 4 in a radially expanding array. The configuration and placement of the cutting elements 5 on blades 4 vary widely depending on factors such as the formation being drilled.

As shown in fig. 2, cutting element 5 includes a layer of superhard material 502 and a substrate 504. The top of the superhard material layer 502 has a working surface 503, and a chamfer 507 is formed between the outer side surface of the cemented carbide substrate 504 and the working surface 503. It should be noted that at least a portion of chamfer 507 may function as working surface 503, which is in contact with the ground during drilling operations. The flat top cutting element of fig. 2 with the ultra-hard material layer 502 is generally the most common and most easily manufactured by known techniques.

During drilling, the face 503 is in contact with the formation, is subjected to peak (high amplitude) pressures generated by normal loads and shear and impact loads applied to the face 503 during drilling. Because the cutting element 5 is typically inserted into the drag bit at a certain back rake angle, the peak stresses acting alone on the working surface 503, or in combination with other factors, such as residual thermal stresses, can create and propagate cracks in and on the surface of the superhard material layer 502 of the cutting element 5. A crack of sufficient length may result in the spalling of a sufficiently large piece of superhard material, rendering the cutting element 5 ineffective or causing the cutting element 5 to fail. When this occurs, drilling operations may have to be stopped in order to remove the drag bit and replace the failed or inactive cutting element 5.

As shown in fig. 3-4, a conventional cutting element cuts a formation 410 using a planar cutting edge, the contact surface being a contact surface 412, and a depth of cut L. During drilling, the ultra-hard material layer 502 cuts rock while resisting strong impact from the rock. Because the working surface of the superhard material layer 502 lacks the flexibility to reduce the contact area, when drilling into a formation with a high gravel content or a hard formation, the cutting element is susceptible to impact damage, resulting in damage to the cutting surface. On the other hand, when drilling into shale, mudstone or other formations, the cuttings produced by the cutting of the diamond composite blades can easily form the elongated cuttings 413. Due to the large size of the cuttings, the cuttings adhere well to the blades 4 and the bit body 3, forming pockets of mud. The cutting faces of the blades of the drill bit are thus wrapped and unable to continue working, ultimately resulting in reduced rates of penetration, no drilling footage, or other problems.

As shown in fig. 5 to 7, the cutting element 5 is substantially cylindrical in form. That is, the substrate 504 is cylindrical. Cutting element 5 includes a layer of superhard material 502 bonded to a substrate 504. The cutting element 5 may be fabricated using a cemented carbide body as the substrate 504 in which tungsten carbide particles are bonded to cobalt. In the sintering process, the super-hard material micro powder (such as diamond or cubic boron nitride) is placed on the hard alloy body, and the mixture bears high pressure under the high-temperature condition. Under this pressure environment, the superhard material particles are thermodynamically stable. This condition causes the grains of superhard material to recrystallize, forming a layer 502 of superhard material directly on the upper surface of the substrate 504. In this embodiment, the superhard material layer 502 is a polycrystalline diamond or polycrystalline cubic boron nitride layer. The top of the superhard material layer 502 has a working face 503 with a chamfer 507 formed between the outer side 505 of the superhard material layer 502 and the working face 503. The angle between the sidewall of body 504 and chamfer 507 is about 45 degrees. At least a portion of the outer side 505 and the chamfer 507 can also function as the working surface 503.

In this embodiment, the angle between the outer side 505 of the superhard material layer 502 and the chamfer 507 is 30 to 60 degrees.

In order to withstand high loads during drilling and to be characterized by chip breaking, the cutting element 5 is provided with a plurality of cutting points or edges. The cutting element 5 is fabricated to incorporate 2 or more cutting edges into the outer circumference of the superhard material layer 502. As is known in the industry, 2 or more cutting edges may form the outer circumference by a machining method.

As shown in fig. 5, the cutting element 5 includes cutting teeth 516. At least one cutting tooth 516 is formed, and the cutting tooth 516 is formed by cutting at the periphery of the superhard material layer 502, so that the orthographic projection of the cutting tooth 516 on the substrate 504 is positioned in the outer circle of the projection plane of the substrate 504. The periphery of the superhard material layer 502 has a plurality of recessed regions 517 with one cutting tooth 516 between adjacent recessed regions 517. If the at least one recessed region 517 is machined into the superhard material layer 502, 2 or more cutting edges may form the outer circumference of the superhard material layer 502. It is therefore also possible to form cutting teeth 516 between 2 recessed regions 517. The cutter teeth 516 may be flat elongated triangular ridges protruding from the outer circumference of the superhard material layer 502. The cutting teeth 516 may also be rounded, pointed, serrated, or other desired shapes. Recessed region 517 may form a conventional cutting element periphery or edge. The recessed region 517 may extend along the entire side of the cutting element or along the height of the cutting element or may extend all or partially along the side of the superhard material layer of the cutting tooth.

In the present embodiment, the number of cutting teeth 516 is 1 to 20.

As shown in fig. 5, substantially recessed regions 517 are formed around the sidewalls of the superhard material layer 502, between each adjacent pair of recessed regions 517, defined as cutting teeth 516. The recessed regions 517 are provided at intervals along the circumferential direction of the superhard material layer 502, and the recessed regions 517 extend downward in the height direction of the superhard material layer 502. Extending through the full depth of the superhard material layer 502 without altering the geometry of the recessed regions 517. In this embodiment, there are a total of 10 recessed regions 517, defined as the same number of cutting teeth 516. Although reference is made herein to the number and location of the recessed regions 517, the application is not limited to the particular arrangements described and illustrated, and it is to be understood that numerous changes and modifications may be made without departing from the scope of the application. For example, if more than one cutting tooth 516 is present in these embodiments, the cutting teeth 516 may be of different sizes and shapes.

In the present embodiment, the radius of the cutting teeth 516 is 10% to 100% of the radius of the cutting element 5.

In this embodiment, the recessed region 517 forms the outer circumference of the superhard material layer 502 at an inward slope angle. Specifically, a plurality of recessed regions 517 form the outer boundary of the superhard material layer 502, the recessed regions 517 starting at the working surface 503, extending in a direction perpendicular to the working surface 503, and gradually ending at the outer side of the substrate 504. In this case, the recessed region 517 is not parallel to the central axis of the cutting element 5. The angle between the recessed region 517 and the central axis of the cutting element 5 is 15 to 45 degrees.

In this embodiment, the working surface 503 is a curved surface.

As shown in fig. 5, the working surface 503 includes a plurality of area surfaces 523. The center of the working surface 503 is higher than the edge of the working surface 503. In the present embodiment, the number of the area faces 523 is equal to the number of the recessed areas 517. The number of land faces 523 is also equal to the number of cutting teeth 516.

As shown in fig. 5, the land face 523 includes cutting ridges. The cutting ridges include a first ridge 530 and a second ridge 534. The first ridge 530 is located between two adjacent area faces 523. The second ridge 534 is located on the area surface 523 between adjacent two of the first ridges 530. Further, the first ridge 530 may be a straight line that slopes upward or downward from the center vertex to the edge, connecting the center of the working surface 503 and the center of symmetry of the cutting tooth 516. Such that each area face 523 has an approximately triangular shape. The first ridge 530 is higher than the second ridge 534 so that the area surface 523 is gradually inclined downward from the first ridge 530 to the second ridge 534.

In an alternative embodiment, the center of the working surface 503 is lower than the edges of the working surface 503. Of course, the center of the working surface 503 may be equal to the edge of the working surface 503, and may be selected according to actual requirements.

As shown in fig. 8 to 9, two adjacent area surfaces 523 may be a planar or curved surface structure. When the region faces 523 are planar, the included angle α between the two region faces 523 intersecting the first ridge 530 is 100 degrees to 179.5 degrees. The second ridge 534 slopes downward from the central apex to the periphery, and the angle β between adjacent regions 523 that meet the second ridge 534 is 180.5 degrees to 260 degrees.

In certain embodiments, the first ridge 530 is a straight line or a curved line connecting the center of the working face 503 and the center of symmetry of the cutter tooth 516. The second ridge 534 is a straight line or a curved line connecting the center of the working face 503 and the center of symmetry of the adjacent cutting tooth 516. The first ridge 530 is higher than the second ridge 534, and the area surface 523 is gradually inclined downward from the first ridge 530 to the second ridge 534.

During cutting with the cutting elements, one, two, or more cutting points or edges may engage the material to be cut, such as rock. As shown in fig. 10-11, the cutting element 5 cuts the formation 410 using a curved cutting edge. The contact surface is contact surface 412 and the depth of cut is L. The cutting element 5 of the present application reduces the overall contact area of the cutting edge during cutting at the same depth of cut, which results in reduced friction and reduced heat generation. For a given weight on bit, the cutting teeth will sink deeper into the rock, resulting in better cutter stability and more efficient rock removal. The cutting area is reduced in fig. 8 compared to the standard cutter area in fig. 3. This provides higher stresses in the rock, resulting in improved efficiency in cutting hard formations.

During drilling, the cutting teeth 516 and the recessed region 517 of the superhard material layer 502 alternately cut rock, which results in a shorter rock chip 413 than would result from continuous cutting using conventional cutting elements. The first ridge 530 separates the strip-shaped debris, which is cut into smaller-sized debris by the cutting element. If concave, the sloping to the top directs the continuing serrations away from the cutting face when compared to standard crushing features, which further reduces friction and heat generation.

In this embodiment, both the first ridge 530 and the second ridge 534 may be used for rock cutting, the configuration of which depends on the rock properties and drilling conditions.

The present application further provides a drill bit including the cutting element 5 described above.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise, and it should be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in other sequences than those illustrated or described herein.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (19)

1. A cutting element, comprising:

a base body, the base body being cylindrical;

the superhard material layer is fixed on the substrate, the top of the superhard material layer is provided with a working surface, and a chamfer is formed between the outer side surface of the superhard material layer and the working surface;

at least one cutting tooth is formed at the periphery of the superhard material layer in a cutting mode, so that the orthographic projection of the cutting tooth on the substrate is positioned in the excircle of the projection plane of the substrate;

cutting ridges located on the working face and corresponding to the cutting teeth one to one.

2. The cutting element of claim 1, wherein the periphery of the superhard material layer has a plurality of recessed regions, and one cutting tooth is disposed between two adjacent recessed regions.

3. The cutting element of claim 2, wherein a plurality of the recessed regions are provided at intervals in a circumferential direction of the super-hard material layer, and the recessed regions extend downward in a height direction of the super-hard material layer.

4. The cutting element of claim 2, wherein the cutting teeth are rounded, pointed, or serrated.

5. The cutting element of claim 2, wherein the number of cutting teeth is 1 to 20.

6. The cutting element of claim 2, wherein a plurality of the recessed regions form an outer boundary of the superhard material layer, the recessed regions beginning at the working face, extending in a direction perpendicular to the working face, and tapering to an outer side of the substrate.

7. The cutting element of claim 6, wherein an angle between the outer side of the superhard material layer and the chamfer is 30 to 60 degrees.

8. The cutting element of claim 6, wherein the working surface is curved.

9. The cutting element of claim 8, wherein the working face includes a number of land faces equal to the number of recessed regions.

10. The cutting element of claim 9, wherein the center of the working face is higher, lower or equal to the edge of the working face.

11. The cutting element of claim 10, wherein the cutting ridge comprises a first ridge located between two adjacent land surfaces.

12. The cutting element of claim 11, wherein the first ridge is a straight line or a curved line, the first ridge connecting a center of the working face and a center of symmetry of the cutting tooth.

13. The cutting element of claim 11, wherein adjacent two of the land surfaces are planar or curved.

14. The cutting element of claim 13, wherein the included angle between two adjacent land surfaces that intersect the first ridge is between 100 degrees and 179.5 degrees.

15. The cutting element of claim 14, wherein the cutting ridges further comprise second ridges on the land between two adjacent first ridges.

16. The cutting element of claim 15, wherein the second ridge is a straight line or a curved line, the second ridge connecting a center of the working face and a center of symmetry of an adjacent cutting tooth.

17. The cutting element of claim 16, wherein the included angle between two adjacent land surfaces that intersect the second ridge is between 180.5 and 260 degrees.

18. The cutting element of any one of claims 1 to 17, wherein the radius of the cutting tooth is 10% to 100% of the radius of the cutting element.

19. A drill bit comprising the cutting element of any one of claims 1 to 18.

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