CN118292768A - Spoon-shaped diamond table on non-planar cutting element - Google Patents

Abstract

A cutting element may include a substrate; and a superhard layer on the substrate, the substrate and superhard layer defining a non-planar working surface of the cutting element such that the superhard layer forms a cutting portion and the substrate is adjacent to the superhard layer at least laterally.

Description

Spoon-shaped diamond table on non-planar cutting element

The application is a divisional application, the application date of the corresponding mother application is 2016, 11 and 24, the application number is 2016007093. X, and the name is a spoon-shaped diamond table on a non-planar cutting element.

Background

Downhole cutting tools come in several types, such as drill bits (including roller cone, hammer, and drag bits), reamers, and mills. Roller cone rock drill bits include a bit body adapted to be coupled to a rotatable drill string and include at least one "cone" rotatably mounted to a cantilevered shaft or journal. Each cone in turn supports a plurality of cutting elements that cut and/or crush the walls or bottom of a borehole, and thus advance the drill bit. During drilling, the cutting elements (buttons or milling teeth) are brought into contact with the formation. Hammer drills generally include a one-piece body having a crown. The crown includes buttons pressed into it, which are periodically "hammered" and rotated against the earth formation being drilled.

Drag bits, commonly referred to as "fixed cutter (cutter) bits," include bits having cutting elements attached to a bit body, which may be a steel body bit body or a matrix bit body formed of a matrix material (such as tungsten carbide) surrounded by a binder material. Drag bits may generally be defined as bits without movable components. However, there are different types of drag bits known in the art and different methods of forming these drag bits. For example, drag bits in which an abrasive material, such as diamond, is impregnated into the surface of the material forming the bit body are often referred to as "impregnated" bits. Drag bits made of superhard cutting surface layers or "tables" (typically made of polycrystalline diamond material or polycrystalline boron nitride material) deposited onto or otherwise bonded to a substrate are known in the art as polycrystalline diamond compact ("PDC") bits.

Disclosure of Invention

This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

In one aspect, embodiments disclosed herein relate to a cutting element comprising a substrate and an ultrahard layer located on the substrate, wherein the substrate and the ultrahard layer define a non-planar working surface of the cutting element such that the ultrahard layer forms a cutting portion and the substrate is adjacent to the ultrahard layer at least in a lateral direction.

In another aspect, embodiments disclosed herein relate to a cutting tool including a tool body; a plurality of blades extending from the tool body; and at least one cutting element attached to one of the plurality of blades. The cutting element includes a substrate; and an ultra-hard layer on the substrate, wherein the substrate and the ultra-hard layer define a non-planar working surface of the cutting element such that the ultra-hard layer forms a cutting portion and the substrate is adjacent to the ultra-hard layer at least laterally.

In yet another aspect, embodiments disclosed herein relate to a cutting tool including a tool body; a plurality of blades extending from the tool body; and at least one cutting element attached to one of the plurality of blades, the at least one cutting element having a non-planar working surface and comprising a substrate and a superhard layer, the non-planar working surface being defined by both the substrate and the superhard layer.

Other aspects and advantages of the claimed subject matter will be apparent from the following detailed description and the appended claims.

Drawings

FIG. 1 is a fixed cutter drill bit;

FIG. 2 is a conventional cutter for a fixed cutter drill bit;

FIG. 3 illustrates one embodiment of a cutting element having a non-planar working surface;

FIG. 4 illustrates a matrix of the cutting element of FIG. 3 in accordance with one embodiment of the present invention;

FIG. 5 illustrates a cross-sectional view of the cutting element of FIG. 3 in accordance with one embodiment of the present invention;

FIG. 6 illustrates a side view of the cutting element of FIG. 3 in accordance with one embodiment of the present invention;

FIG. 7 illustrates a top view of one embodiment of a cutting element having a non-planar working surface;

FIG. 8 illustrates a cross-sectional view of the cutting element of FIG. 7 in accordance with one embodiment of the present invention;

FIG. 9 is a matrix of the cutting element of FIG. 7 in accordance with one embodiment of the present invention;

FIG. 10 illustrates one embodiment of a cutting element having a non-planar working surface;

FIG. 11 illustrates a matrix of the cutting element of FIG. 10 in accordance with one embodiment of the present invention;

FIG. 12 illustrates a side view of the cutting element of FIG. 10 in accordance with one embodiment of the present invention;

FIG. 13 illustrates a side view of the cutting element of FIG. 10 in accordance with one embodiment of the present invention;

FIG. 14 illustrates one embodiment of a cutting element having a non-planar working surface;

FIG. 15 illustrates a matrix of the cutting element of FIG. 14 in accordance with one embodiment of the present invention;

FIG. 16 illustrates a side view of the cutting element of FIG. 14 in accordance with one embodiment of the present invention;

FIG. 17 is a side view of the cutting element of FIG. 14 according to one embodiment of the present invention;

FIG. 18 illustrates one embodiment of a cutting element having a non-planar working surface;

FIG. 19 illustrates a matrix of the cutting element of FIG. 18 in accordance with one embodiment of the present invention;

FIG. 20 illustrates a matrix of the cutting element of FIG. 18 in accordance with one embodiment of the present invention;

FIG. 21 illustrates one embodiment of a cutting element having a non-planar working surface;

FIG. 22 illustrates a matrix of the cutting element of FIG. 21 in accordance with one embodiment of the present invention;

FIG. 23 illustrates a side view of the cutting element of FIG. 21 in accordance with one embodiment of the present invention;

FIG. 24 illustrates a cross-sectional view of the cutting element of FIG. 21 in accordance with one embodiment of the present invention;

FIG. 25 illustrates one embodiment of a cutting element having a non-planar working surface;

FIGS. 26-28 illustrate views of a substrate of the cutting element of FIG. 25, according to one embodiment of the present invention;

FIG. 29 illustrates one embodiment of a cutting element having a non-planar working surface;

FIG. 30 illustrates a matrix of the cutting element of FIG. 29 in accordance with one embodiment of the present invention;

FIG. 31 illustrates a side view of the cutting element of FIG. 29 in accordance with one embodiment of the present invention;

FIG. 32 illustrates a cross-sectional view of the cutting element of FIG. 29 in accordance with one embodiment of the present invention;

FIG. 33 illustrates a reamer in accordance with an embodiment of the present invention.

Detailed Description

In one aspect, embodiments disclosed herein relate to cutting elements having non-planar working surfaces, and also to cutting tools having such cutting elements attached thereto. In particular, embodiments disclosed herein relate to cutting elements having a non-planar working surface formed from both a substrate and diamond.

One example of a drag bit having a plurality of cutting elements with superhard working surfaces is shown in fig. 1. The drill bit 100 includes a bit body 110 having a cutting end 115 and a threaded upper pin end 111. The cutting end 115 generally includes a plurality of ribs or blades 120 disposed about a rotational axis (also referred to as a longitudinal axis or central axis) of the drill bit and extending radially outward from the bit body 110. Cutting elements or teeth 150 are embedded in the blades 120 at predetermined angular orientations and radial positions relative to the working surface and against the formation to be drilled at desired back and side rake angles.

Fig. 2 illustrates one example of a cutting element 150, wherein the cutting element 150 has a cylindrical cemented carbide (carbide) substrate 152 having an end or upper surface 154 (referred to herein as a substrate interface surface). The layer of superhard material 156 (also referred to as a cutting layer) has a top surface 157 (also referred to as a working surface), a cutting edge 158 formed around the top surface, and a bottom surface 159 (referred to herein as a superhard material layer interface surface). The layer of superhard material 156 may be a layer of polycrystalline diamond or polycrystalline cubic boron nitride. The superhard material layer interface surface 159 is bonded to the substrate interface surface 154 to form a planar interface between the substrate 152 and the superhard material layer 156.

Referring to fig. 3, fig. 3 illustrates one embodiment of a cutting element. The cutting element 300 includes a substrate 302 and a superhard layer 304 disposed on the substrate 302. While conventional PDC cutting elements include a superhard layer covering the entire upper surface of the substrate (such that the working surface of the cutting element is entirely superhard material), the cutting elements of the present disclosure include a superhard layer 304 having a smaller cross-sectional area than the substrate 302 such that both the substrate 302 and the superhard layer 304 form the working surface 306 of the cutting element 300. The working surface 306 is non-planar. There is no limitation on the shape of the non-planar working surface 306. In the illustrated embodiment, the non-planar working surface 306 is generally a parabolic cylinder with planar sides, with peak tips (apex) 308 extending from one side of the cutting element to the other, and the height of the working surface 306 decreases in a direction extending laterally away from the tip 308 (such decreasing lateral portions of the working surface are optionally planar, rather than curved). However, the superhard layer 304 does not form the entire surface, but does at least form a cutting edge (at the intersection of the tip 308 and peripheral edge 310 of the cutting element) and extends radially inward toward the central axis 301 of the cutting element 300. As shown in fig. 21-24 and discussed in further detail below, the ultra-hard layer 304 need not extend the entire diameter of the cutting element 300, nor even to the central axis 301. In addition, in the embodiment illustrated in fig. 3, the superhard layer 304 is an elongated (longer than longer) section forming the tip 308 and defining a cutting edge extending from the cutting edge on the first side to the second side of the cutting element. The base 302 extends along both lateral sides of the elongated section. Thus, the peripheral edge 310 of the non-planar working surface 306 (formed at the intersection between the non-planar working surface 306 and the cylindrical side surface 312 of the cutting element) has at least one base portion and at least one superhard layer portion. The base portion extends away from the cutting edge formed by the superhard layer 304. In the illustrated embodiment, the peripheral edge 310 includes two substrate portions and two superhard layer portions.

To increase the surface area of the interface between the superhard layer 304 and the substrate 302, the elongate section of the superhard layer 304 may have varying dimensions along its length. For example, as shown in fig. 3 (and in fig. 4, which shows a substrate 302 without an ultra-hard layer 304, particularly showing an interface surface 303 upon which the ultra-hard layer 304 is deposited), the ultra-hard layer 304 as an elongate section may be wider at its ends (adjacent the cutting edge) than at a radially inner portion of the elongate section (such as near the central axis 301). For example, as shown in fig. 6 (a side view of the cutting element 300 of fig. 3), the width w of the elongate section at its ends may range from about 60% to about 80% of the cutting element diameter. However, depending on the depth of cut for a particular drilling application, other ranges may be required to ensure surface coverage of the diamond. For 16mm cutting teeth, such a width may be in the range of 0.400 inches to about 0.500 inches.

Furthermore, as shown in fig. 5 (which shows a cross-sectional view of the cutting element 300 of fig. 3), the superhard layer 304 as an elongate section may also be thicker at its ends (adjacent the cutting edge) than at the radially inner portion (such as near the central axis 301). In one embodiment, the thickness t1 of the superhard layer 304 at its thinnest point may be in the range of about 0.030 inches to about 0.150 inches. However, depending on the size of the cutting element, the thickness may vary. Thus, for example, in one or more embodiments, the thickness t1 of the superhard layer 304 at its thinnest point may be in the range of from about 4 to 40 percent of the outer diameter of the cutting element. In addition, those skilled in the art will appreciate that this thickness may be used for those embodiments that extend through the central axis 301, while the embodiments with discontinuous ultrahard layers illustrated in fig. 21-24 have a minimum thickness of zero at the central axis. In addition, the superhard layer 304 may have a thickness t2 measured from the cutting edge to the substrate 302 (measured at the cross-section along a line bisecting the angle formed between the working surface 306 and the side surface 312 of the cutting element 300), the thickness being in the range of from about 0.120 inches to about 0.180 inches. In one or more embodiments, the thickness t2 may be in a range from about 10% to 40% of the outer diameter of the cutting element.

In addition to having a non-planar working surface, the interface surface 303 (shown in figures 4 and 5) between the substrate 302 and the super-hard layer 304 is also non-planar. In particular, the non-planar interface surface 303 may be formed by at least one groove 305 formed in the upper surface of the substrate 302. In one or more embodiments, the groove 305 can have an elongated (longer than longer) shape to receive an elongated section of the ultrahard layer 304. In addition, along the length of the elongated groove 305 (shown in the cross-sectional view of fig. 5), the base 302 may have a generally convex curvature (curvature) that may be generally parabolic (in a cross-section corresponding to the groove length) such that the ends of the elongated sections of the ultra-hard layer 302 are thicker than the radially inward portions. In one or more embodiments, the groove 305 can have a varying radius of curvature along its length, which can cause a variation in the width of the elongated section of the ultrahard layer 304. For example, as is apparent in fig. 5, the groove 305 may have its smallest radius of curvature near the central axis 301 or midline (the cross-sectional plane bisecting the elongate curve and on which the central axis lies) and its largest radius of curvature at the intersection with (or near) the side surface 312. The ratio between the maximum radius of curvature and the minimum radius of curvature may be between 200:0.01 and 1:0.99, or between 200:1 and 1:0.9, or may be less than 100:1, 50:1, 25:1, 10:1, 5:1 or 3.5:1 and/or at least 1.5:1, 2:1 or 2.5:1.

Referring now to fig. 7-9, another embodiment of a cutting element is shown. As shown, the cutting element 700 includes a substrate 702 and a superhard layer 704 on the substrate 702. The cutting element has a non-planar working surface 706 formed by both the substrate 702 and the superhard layer 704 such that the superhard layer 704 is an elongate section, similar to the elongate section in figure 3. Similar to the embodiments described above, the elongate section of the super-hard layer 704 has a recess 705 with a varying radius of curvature along the length of the elongate section to form a non-planar interface 703 between the substrate 702 and the super-hard layer 704. However, unlike the embodiments described above that have a minimum radius of curvature near the central axis 701, there is a minimum radius of curvature along the elongate section between the end of the elongate section and the central axis 701. Similarly, the thickness and width of the elongate section of the super-hard layer 704 may vary in the same manner, i.e. with its maximum value at the end of the elongate section, with an intermediate value at the central axis, and with its minimum value between the central axis and the end of the elongate section. Further, in such embodiments, the base 702 may have a generally convex curvature along the length of the elongated groove 705 (shown in the cross-sectional view of fig. 8), and optionally have a convex portion at or near the central axis 701. In one or more different embodiments, the minimum radius of curvature along the elongate section may still be located between the end of the elongate section and the central axis 701; however, the thickness of the elongate section of the superhard layer 704 may have its minimum at or near the central axis 701, rather than having its minimum at some point between the end and the central axis 701.

Referring now to fig. 10-13, another embodiment of a cutting element is shown. As shown, cutting element 1000 includes a substrate 1002 and a superhard layer 1004 disposed on substrate 1002. The cutting element has a non-planar working surface 1006 formed by both the substrate 1002 and the superhard layer 1004 such that the superhard layer 1004 is an elongate section similar to the elongate section in figures 3 to 9. While the above embodiment includes a single groove to form the non-planar interface, the embodiment illustrated in figures 10 to 13 includes a plurality of grooves 1005 (two in this embodiment) extending along the length of the elongate section of superhard material 1004 to form the non-planar interface 1003. The groove 1005 has a varying radius of curvature (varying from a maximum adjacent the side surface 1012 to a minimum near the midline of the central axis 1001). In addition, grooves 1005 are substantially parallel to each other. Elongated peaks or protrusions of the matrix 1002 extend between the plurality of grooves 1005, also forming part of the interface surface 1003. In addition, along the length of the elongate groove 1005, the substrate 1002 may have a generally convex curvature such that the ends of the elongate sections of the superhard layer 1002 are thicker than the radially inward portions.

Referring now to fig. 14-17, another embodiment of a cutting element is shown. As shown, cutting element 1400 includes a substrate 1402 and a superhard layer 1404 disposed on substrate 1402. The cutting element has a non-planar working surface 1406 formed by both the substrate 1402 and the superhard layer 1404 such that the superhard layer 1404 is an elongate section similar to the elongate section in figures 3 to 13. While the above embodiments illustrate grooves aligned with the length of an elongated segment to form a non-planar interface, the embodiments illustrated in fig. 14-17 include a first set of grooves 1411 aligned with the length of an elongated segment and a second set of grooves 1413 not aligned with the length of an elongated segment to form a non-planar interface 1403. In one or more embodiments, the first set of grooves 1411 and the second set of grooves can be substantially perpendicular to each other. In addition, as shown, each set of grooves 1411, 1413 includes a plurality of parallel grooves (specifically, two parallel grooves 1411 and three parallel grooves 1413). However, it is also contemplated that the grooves 1411, 1413 in either direction may include one groove instead of a plurality or set of grooves. Each of the grooves 1411, 1413 has a varying radius of curvature along its length. For grooves 1411 extending along a length corresponding to the length of the elongate section, the radius of curvature has its maximum adjacent the side surface 1412 and decreases toward a midline (of the elongate section) proximate the central axis 1401, but increases after intersecting grooves 1413-1 extending along the length of the midline. The grooves 1413 extend substantially perpendicular to the grooves 1411. In the illustrated embodiment, groove 1413-1 extends within an interior portion of base 1402 (i.e., does not intersect side surface 1412) along a midline 1407 that bisects the length of groove 1411 and extends through central axis 1401. Furthermore, there are two grooves 1413-2 extending substantially parallel to the grooves 1413-1, intersecting the side surface 1412 at each end corresponding to the elongated section. As mentioned, each of the grooves 1413 has a varying radius of curvature with a maximum at the ends of the groove and a minimum between the grooves 1411.

Although, as mentioned above, the super-hard layer extends the entire diameter of the cutting element, the present disclosure is not so limited. Instead, as shown in fig. 21-24, cutting element 2100 includes a substrate 2102 and a super-hard layer 2104 located on substrate 2102. The cutting element has a non-planar working surface 2106 formed by both the base 2102 and the super-hard layer 2104; however, the super-hard layer 2104 does not form an elongated section extending across the entire length of the cutting element diameter, but rather is a discontinuous layer having two discrete sections with a portion of the matrix 2102 located between the two discrete sections. Thus, an inner portion of the peak (crest) 2110 (which extends from the cutting edge to the other side of the cutting element) is formed by the base 2102 (including at the central axis). However, the super-hard layer 2104 may form at least 50% of the length of the peaks 2110. Similar to that described with respect to fig. 3, each section of superhard layer 2104 may have varying dimensions along its length. In particular, each segment of superhard layer 2104 may be wider at its end (adjacent the cutting edge) than the radially inner portion of the segment, and the width of each segment may range from about 60 to about 80 percent of the cutting element diameter, as shown in the side view of fig. 23. However, depending on the depth of cut for a particular drilling application, other ranges may be required to ensure surface coverage of the diamond. Further, as shown in fig. 24, each segment of superhard layer 2104 can have a varying thickness. In particular, each segment of superhard layer 2104 may have a peak thickness t4 and a thickness t3 at the outer circumference, the thickness t3 being in the range of from about 0.030 inch to about 0.150 inch (or from about 4% to 40% of the outer diameter of the cutting element), the peak thickness t4 being anywhere between the Outer Diameter (OD) of the cutting tooth and the central axis of the cutting tooth and in the range of from about 0.050 inch to about 0.180 inch (or from about 8% to 45% of the outer diameter of the cutting element). In addition to having a non-planar working surface, the interface surface 2103 between the substrate 2102 and the super-hard layer 2104 is also non-planar. In particular, the non-planar interface surface 2103 may be formed by two recesses 2105 on either side of the cutting element. Each recess 2105 may include two substantially parallel grooves 2107 that, together with the remainder of the recess 2105, define a non-planar interface 2103.

Referring now to fig. 18-20, another embodiment of a cutting element is shown. As shown, cutting element 1800 includes a substrate 1802 and a superhard layer 1804 on substrate 1802. The cutting element 1800 has an axisymmetric non-planar working surface 1806 formed by both the substrate 1802 and the superhard layer 1804. However, unlike the above-described embodiments having a non-planar working surface shaped generally as a parabolic cylinder, the embodiment illustrated in fig. 18-20 includes a substantially conical non-planar working surface 1806 terminating in a rounded tip. The substantially conical non-planar working surface 1806 includes a cutting tip (tip) formed from a superhard layer 1804 surrounded by a substrate 1802. While conventional substantially conical cutting elements have an entire conical surface formed of superhard material (and in fact, superhard material may form part of the cylindrical side surface), in accordance with the presently illustrated embodiment, the substrate 1802 forms part of the substantially conical surface. Unlike those embodiments shown above, the superhard layer 1804 is not an elongate section; however, due to the non-planar interface 1803 between the superhard layer and the substrate 1802, the superhard layer remains laterally supported by the substrate. As illustrated, this lateral support results in a wavy pattern of interfaces 1803 at the work surface 1806. The peaks of the substrate may be designed to avoid engagement with the formation at a particular depth of cut for a given cutting element back rake angle (angle between the cutting element and a line perpendicular to the formation to be engaged), and as illustrated in fig. 20, the back rake angle of plane 1820 is 17 degrees and the depth of cut is 0.025 inches. However, the present disclosure is not limited to a 17 degree back rake angle and a 0.025 inch depth of cut, and thus, the thickness may vary depending on the depth of cut and back rake angle to avoid or minimize substrate engagement with the formation. The non-planar interface 1803 is formed by two sets of grooves 1811, 1813, each set having two grooves, and the two sets being substantially perpendicular to each other. Each of the grooves 1811, 1813 has substantially the same length, thereby imparting rotational and bit lateral symmetry to the super hard layer 1804. In addition, each of the grooves 1811, 1813 has a varying radius of curvature with a maximum at the ends of the grooves 1811, 1813 and a minimum at the middle length of the grooves 1811, 1813. Although two sets of grooves 1811, 1813 are illustrated, it is also contemplated that in some embodiments a single set of grooves may be used instead.

Referring now to fig. 25-28, another embodiment of a cutting element is shown. As shown, cutting element 2500 includes a substrate 2502 and a superhard layer 2504 disposed on substrate 2502. Cutting element 2500 has an axisymmetric non-planar working surface 2506 formed by both substrate 2502 and superhard layer 2504. Similar to the embodiment illustrated in fig. 18-20, the cutting element of fig. 25-28 includes a substantially conical non-planar working surface 2506 terminating in a rounded tip. The substantially conical non-planar working surface 2506 comprises a cutting tip formed by a superhard layer 2504 surrounded by a substrate 2502. While conventional substantially conical cutting elements have an entire conical surface formed of superhard material (and in fact, superhard material may form part of the cylindrical side surface), in accordance with the presently illustrated embodiment, the substrate 2502 forms part of the substantially conical surface. Unlike the embodiments illustrated above in fig. 18-20, the superhard layer 2504 is an elongate section and is laterally supported by the substrate 2502. Because the superhard layer 2504 is an elongated segment, it extends to the cylindrical portion of the cutting element in a direction other than the perpendicular direction, thereby forming a longer-than-wider segment. In addition, it is contemplated that the ultra-hard layer 2504 may be elongated without reaching the cylindrical portion (i.e., the outer diameter of the cutting element), but still be longer than wide.

The elongate section of the ultrahard layer 2504 can have varying dimensions along its length. The ultra-hard layer 2504 as an elongate section may be wider at its ends (adjacent the cylindrical portion) than the radially inner portion, but as illustrated, the width near the central axis 2501 may also be greater than the minimum width. In one or more embodiments, the recess 2505 may have a varying radius of curvature along its length, which may result in a variation in the width of the elongate section of the superhard layer 2504.

The non-planar interface surface 2503 may be formed by at least one recess 2505 formed in an upper surface of the base 2502. In one or more embodiments, the recess 2505 may have an elongated (longer than longer) shape to receive an elongated section of the superhard layer 2504. In addition, along the length of the elongate recess 2505 (shown in the perspective view of fig. 26), the base 2502 may have a generally convex curvature, which may be generally parabolic (in cross-section corresponding to the length of the recess).

Referring now to fig. 29-32, another embodiment of a cutting element is shown. As shown, cutting element 2900 includes substrate 2902 and super-hard layer 2904 located on substrate 2902. Cutting element 2900 has an axisymmetric non-planar working surface 2906 formed by both substrate 2902 and superhard layer 2904. Similar to the embodiment illustrated in fig. 18-28, the cutting element of fig. 29-32 includes a substantially conical non-planar working surface 2906 terminating in a rounded tip. The substantially conical non-planar working surface 2906 includes a cutting tip formed by superhard layer 2904 surrounded by substrate 2902. While conventional substantially conical cutting elements have an entire conical surface formed of superhard material (and in fact, superhard material may form part of the cylindrical side surface), substrate 2902 forms part of the substantially conical surface according to the presently illustrated embodiment. Unlike the embodiments illustrated above in fig. 18-20, and similar to the embodiments illustrated in fig. 25-28, ultrahard layer 2904 is an elongated section and is laterally supported by substrate 2902. Because ultrahard layer 2904 is an elongated segment, it extends to the cylindrical portion of the cutting element in a direction other than the perpendicular direction, forming a longer-than-wider segment. In addition, it is also contemplated that the ultra-hard layer 2904 may be elongated without reaching the cylindrical portion (i.e., the outer diameter of the cutting element), but still be longer than wide. As shown, superhard layer 2904 reaches the cylindrical portion (i.e., the other diameter of the cutting element) at one end of the elongate section, but does not extend to the cylindrical portion at the other end.

The elongated section of the ultrahard layer 2904 may have varying dimensions along its length. Ultrahard layer 2904, which is an elongate section, may be wider at its ends (adjacent to or near the cylindrical portion) than the radially inner portion, but may also have a width near central axis 2901 that is greater than the minimum width, or the width near central axis 2901 may be the minimum width. In one or more embodiments, groove 2905 may have a varying radius of curvature along its length, which may cause a variation in the width of the elongated section of superhard layer 2904.

The non-planar interface surface 2903 may be formed by at least one groove 2905 formed in the upper surface of the substrate 2902. In one or more embodiments, groove 2905 may have an elongated (longer than longer) shape to receive an elongated section of superhard layer 2904. In addition, along the length of the elongated groove 2905 (shown in the perspective view of fig. 30), the substrate 2902 may have a generally convex curvature, which may be generally parabolic (in cross-section corresponding to the groove length).

Other shapes of non-planar working surfaces may be used in addition to the geometries shown in fig. 3-17, including other axisymmetric non-planar working surfaces that do not have a conical surface, but may have a generally convex or concave surface that terminates in a rounded tip. In addition, other non-planar work surfaces may include other types of symmetry, such as bilateral symmetry (examples of which are shown in the embodiments of fig. 3-17) or rotational symmetry, as well as asymmetric work surfaces. In any of such non-planar working surfaces, the substrate may define a portion of the non-planar working surface such that the ultra-hard layer provides a desired thickness in the portion of the cutting element that engages the formation during drilling, and the substrate provides lateral support to the ultra-hard layer in areas designed not to contact the formation during drilling.

In the case of cutting elements with conical or other axisymmetric non-planar working surfaces, the back rake angle may be the angle between the cutting element axis and a line perpendicular to the formation to be joined, while in the case of cutting elements as shown in fig. 3-17, the back rake angle may be calculated between the following two lines: a line extending from the cutting tip across the diameter of the cutting element, and a line perpendicular to the formation to be joined. In one or more embodiments, the cutting element of fig. 18 may have a back rake angle in the range from about-30 degrees to 30 degrees; however, it is also conceivable that a larger back rake angle of up to 80 degrees could be used. In one or more embodiments, the cutting elements of fig. 3-17 may have a back rake angle in the range from about 0 degrees to-20 degrees.

Each of the embodiments described herein has at least one ultrahard layer (made of ultrahard material) contained therein. Such superhard materials may include conventional polycrystalline diamond tables (tables of interconnected diamond particles with interstitial spaces between the particles where metal components such as metal catalysts may be present, thermally stable diamond layers (i.e. thermally stable greater than conventional polycrystalline diamond (750 ℃)), formed for example by removal of substantially all metal from the interstitial spaces between the interconnected diamond particles or diamond/silicon carbide composite, or other superhard materials such as cubic boron nitride.

As known in the art, thermally stable diamond may be formed in various ways. Conventional polycrystalline diamond layers comprise individual diamond "crystals" interconnected. The individual diamond crystals thus form a lattice structure. Metal catalysts (such as cobalt) may be used to promote recrystallisation of the diamond particles, as well as to form a lattice structure. Thus, cobalt particles tend to be found in interstitial spaces in the diamond lattice structure. Cobalt has a significantly different coefficient of thermal expansion than diamond. Thus, upon heating the diamond table, the cobalt and diamond lattice will expand at different rates, thereby forming cracks in the lattice structure and causing degradation of the diamond table.

To avoid this problem, strong acids may be used to "leach" cobalt from the polycrystalline diamond lattice structure (either in thin volume or in monolithic form (entire tablet)) to at least mitigate the damage suffered by heating the diamond-cobalt composite material at different rates upon heating. Briefly, a strong acid (typically hydrofluoric acid or a combination of several strong acids) may be used to treat the diamond table to remove at least a portion of the promoter from the PDC composite. Suitable acids include nitric acid, hydrofluoric acid, hydrochloric acid, sulfuric acid, phosphoric acid, or perchloric acid, or combinations of these acids. In addition, corrosives such as sodium hydroxide and potassium hydroxide have been used in the carbide industry to digest metallic elements in carbide composites. In addition, other acidic leaches and alkaline leaches may be used as desired. Those of ordinary skill in the art will appreciate that the molar concentration of the leaching agent may be adjusted depending on the time desired for leaching, concerns about hazards, etc.

By leaching cobalt, thermally Stable Polycrystalline (TSP) diamond may be formed. In certain embodiments, selected portions of the diamond composite are leached in order to obtain thermal stability without loss of impact resistance. As used herein, the term TSP includes both of the above-described (i.e., partially leached and fully leached) compounds. The interstitial volume left after leaching can be reduced by further consolidation (consolidation) or filling the volume with a secondary material.

Alternatively, the TSP may be formed by forming a diamond layer in a press using a binder other than cobalt (such as silicon) that has a coefficient of thermal expansion that is closer to that of diamond than that of cobalt. During the manufacturing process, a large portion (80 to 100 volume percent) of the silicon reacts with the diamond lattice to form silicon carbide, which also thermally expands similar to diamond. Upon heating, any remaining silicon, silicon carbide and diamond lattice will expand at a more similar rate than the rate of expansion of cobalt and diamond, resulting in a layer of higher thermal stability. PDC cutters with TSP cutting layers have relatively low wear rates even at cutter temperatures up to 1200 ℃. However, one of ordinary skill in the art will recognize that the thermally stable diamond layer may be formed by other methods known in the art, including, for example, by altering the process conditions during the formation of the diamond layer.

The substrate on which the ultrahard layer is disposed may be formed of various hard particles. In one embodiment, the matrix may be formed of a suitable material, such as tungsten carbide, tantalum carbide, or titanium carbide. In addition, various binding metals (such as cobalt, nickel, iron, metal alloys, or mixtures thereof) may be included in the matrix. In the matrix, metal carbide grains are supported within a metal binder (such as cobalt). In addition, the substrate may be formed of a cemented tungsten carbide composite structure. It is well known that various metal carbide compositions and binders other than tungsten carbide and cobalt may be used. Thus, the use of tungsten carbide and cobalt is mentioned for illustrative purposes only and is not intended to limit the type of matrix or binder used.

While the cutting elements of the present disclosure may be used on a drill bit (such as the type shown in fig. 1), it is also contemplated that these cutting elements may be used on other types of downhole tools, including, for example, reamers. FIG. 33 illustrates a general configuration of a reamer 830 including one or more cutting elements of the present disclosure. Reamer 830 includes a tool body 832 and a plurality of blades 838 disposed at selected azimuthal locations about the circumference of the reamer. The reamer 830 generally includes connections 834, 836 (e.g., threaded connections) such that the reamer 830 may be coupled to adjacent drilling tools, including, for example, a drill string and/or a Bottom Hole Assembly (BHA) (not shown). The tool body 832 generally includes a bore therethrough such that drilling fluid may flow through the reamer 830 as the drilling fluid is pumped from the surface (e.g., from a surface mud pump (not shown)) to the bottom of the wellbore (not shown).

Although only a few exemplary embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the application. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. The inventors' expression is intended not to refer to the 35 th 112 th paragraph of the united states code for any limitation to any claim herein, except that a claim explicitly uses the word "means for … …" along with those limitations of the relevant function.

Claims (20)

1. A cutting element, comprising:

A base; and

A superhard layer on the substrate, the substrate and the superhard layer defining a non-planar working surface of the cutting element such that the superhard layer forms a cutting portion and the substrate is adjacent to the superhard layer at least laterally.

2. The cutting element of claim 1, wherein the superhard layer forms a cutting edge and extends radially inward toward a central axis of the cutting element.

3. The cutting element of claim 2, wherein the ultrahard layer is an elongated section extending from the cutting edge on a first side to a second side of the cutting element, and wherein the matrix extends along both sides of the elongated section.

4. The cutting element of claim 3, wherein the elongate section is wider at its ends than a radially inner portion of the elongate section.

5. The cutting element of claim 4, wherein the elongate section is wider at its ends than near the central axis.

6. The cutting element of claim 2, wherein a width of the elongate section along at least one of its ends is in a range from about 60% to about 80% of a diameter of the cutting element.

7. The cutting element of claim 3, wherein the thickness of the elongate section at its thinnest point is in the range of from about 4% to 40% of the outer diameter of the cutting element.

8. A cutting element according to claim 3, wherein said elongate section is thicker at its ends than near said central axis.

9. The cutting element of claim 1, wherein the cutting element has an axisymmetric non-planar working surface with a cutting tip formed by the superhard layer surrounded by the substrate.

10. The cutting element of claim 1, wherein the peripheral edge of the non-planar working surface has at least one base portion and at least one superhard layer portion, the at least one base portion extending away from the cutting edge formed by the superhard layer.

11. The cutting element of claim 1, wherein an interface between the ultra-hard layer and the substrate opposite the non-planar working surface comprises at least one groove formed in the substrate, the groove having a varying radius of curvature.

12. The cutting element of claim 11, wherein the interface comprises a plurality of parallel grooves.

13. The cutting element of claim 11, wherein the interface comprises two sets of parallel grooves, the two sets being substantially perpendicular to each other.

14. The cutting element of claim 2, wherein at the central axis, the matrix forms the non-planar working surface.

15. A cutting tool, comprising:

tool body

A plurality of blades extending from the tool body; and

The cutting element of claim 1 attached to at least one of the plurality of blades.

16. A cutting tool, comprising:

A tool body;

A plurality of blades extending from the tool body; and

At least one cutting element attached to one of the plurality of blades, the at least one cutting element having a non-planar working surface and comprising a substrate and a superhard layer, the non-planar working surface being defined by both the substrate and the superhard layer.

17. The cutting tool of claim 16, wherein the ultra-hard layer is an elongated section extending from the cutting edge on a first side to a second side of the cutting element, and wherein the matrix extends along both sides of the elongated section.

18. The cutting tool of claim 16, wherein the cutting element has an axisymmetric non-planar working surface with a cutting tip formed by the superhard layer surrounded by the substrate.

19. The cutting tool of claim 16, wherein the peripheral edge of the non-planar working surface has at least one base portion and at least one superhard layer portion, the at least one base portion extending away from the cutting edge formed by the superhard layer.

20. The cutting tool of claim 16, wherein an interface between the ultra-hard layer and the substrate opposite the non-planar working surface comprises at least one groove formed in the substrate, the groove having a varying radius of curvature.