Plow-shaped cutting elements for earth-boring tools, earth-boring tools including such cutting elements, and related methods

Abstract

A cutting element for an earth-boring tool includes at least one volume of superabrasive material on a substrate. The volume of superabrasive material includes a first planar surface and a second planar surface oriented at an angle relative to the first planar surface and intersecting the first planar surface along an apex. The first planar surface has a circular or oval shape having a first maximum diameter, and the second planar surface has a circular or oval shape having a second maximum diameter. The apex has a length less than the first maximum diameter and the second maximum diameter. Earth-boring tools include such a cutting element attached to a body. Methods of forming earth-boring tools include the attachment of such a cutting element to a body of an earth-boring tool.

Claims

1. A cutting element for an earth-boring tool, comprising: a substrate comprising superabrasive material; a first front cutting surface of the substrate having a first shape comprising more than half of a circle or more than half of an oval, the first shape having a first maximum diameter; a second front cutting surface of the substrate having a second shape comprising more than half of a circle or more than half of an oval, the second shape having a second maximum diameter, the second front cutting surface oriented at an angle relative to the first front cutting surface and intersecting the first front cutting surface along an apex having a length less than the first maximum diameter and the second maximum diameter; and notches extending longitudinally in a lateral side surface of the cutting element on opposing sides adjacent the apex.

2. The cutting element of claim 1, wherein each of the first front cutting surface and the second front cutting surface is planar, and the apex is linear.

3. The cutting element of claim 1, wherein the first front cutting surface and the second front cutting surface are symmetrical with respect to the apex and are coextensive.

4. The cutting element of claim 1, wherein the first front cutting surface and the second front cutting surface differ from one another in at least one of size, shape, or orientation.

5. The cutting element of claim 1, wherein the cutting element has a tapered geometry, the lateral side surface of the cutting element having a frustoconical shape.

6. The cutting element of claim 1, wherein the superabrasive material comprises at least one of polycrystalline diamond or cubic boron nitride.

7. The cutting element of claim 1, wherein a thickness of the superabrasive material varies at different locations on the substrate of the cutting element, the superabrasive material having a maximum thickness at the apex and a decreasing thickness with increased distance from the apex.

8. An earth-boring tool, comprising: a body; at least one cutting element attached to the body, the at least one cutting element comprising: a first front cutting surface and a second front cutting surface, wherein each of the first front cutting surface and the second front cutting surface comprises a shape having more than half of a circle or more than half of an oval, each of the first front cutting surface and the second front cutting surface has a maximum diameter, and the second front cutting surface is oriented at an angle relative to the first front cutting surface and intersecting the first front cutting surface along an apex having a length less than the maximum diameter of each of the first front cutting surface and the second front cutting surface; and notches extending longitudinally in a lateral side surface of the at least one cutting element on opposing sides adjacent the apex.

9. The earth-boring tool of claim 8, wherein the apex is linear, and each of the first front cutting surface and the second front cutting surface is planar.

10. The earth-boring tool of claim 8, wherein the apex is oriented substantially perpendicular to a surface of the body surrounding the cutting element.

11. The earth-boring tool of claim 8, wherein: the at least one cutting element comprises a plurality of cutting elements defining a cutting element profile; and at least some of the cutting elements are attached to the body and positioned at a same radial position at a single point along the cutting element profile.

12. The earth-boring tool of claim 8, wherein the earth-boring tool comprises a fixed-cutter rotary drill bit.

13. The earth-boring tool of claim 12, wherein the fixed-cutter rotary drill bit comprises a coring bit having a generally cylindrical void defined at a center of the body.

14. The earth-boring tool of claim 13, wherein the at least one cutting element is attached to the body at a location adjacent the generally cylindrical void, at least one lateral side surface of the at least one cutting element proximate the generally cylindrical void.

15. The earth-boring tool of claim 14, wherein a lateral cutting edge of the at least one cutting element, remote from the apex, is positioned to cut and define a core of a formation extending into the generally cylindrical void during drilling.

16. The earth-boring tool of claim 15, wherein the at least one cutting element has an effective back rake angle relative to the core of the formation.

17. A method of drilling a formation, comprising: rotating an earth-boring tool in contact with a formation to engage the formation with a plurality of cutting elements, at least some of the cutting elements comprising a first front cutting surface and a second front cutting surface oriented at an angle relative to the first front cutting surface and intersecting the first front cutting surface along an apex, the first front cutting surface and the second front cutting surface each having a shape comprising more than half of a circle or more than half of an oval, the first front cutting surface having a first maximum diameter and the second front cutting surface having a second maximum diameter, and the apex having a length less than the first maximum diameter and the second maximum diameter, wherein notches extend longitudinally in a lateral side surface of the plurality of cutting elements on opposing sides adjacent the apex.

18. The method of claim 17, wherein rotating the earth-boring tool in contact with the formation comprises rotating a coring bit having a generally cylindrical void defined at a center of the coring bit.

19. The method of claim 18, further comprising engaging the formation with the at least some of the cutting elements located adjacent the generally cylindrical void.

20. The method of claim 19, wherein engaging the formation comprises contacting the formation with a lateral cutting edge of the at least some of the cutting elements, remote from the apex, the at least some of the cutting elements having an effective back rake angle relative to a core of the formation extending into the generally cylindrical void.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) While the specification concludes with claims particularly pointing out and distinctly claiming what are regarded as embodiments of the disclosure, various features and advantages of this disclosure may be more readily ascertained from the following description of example embodiments provided with reference to the accompanying drawings, in which:

(2) FIGS. 1A-1C are perspective views illustrating an example embodiment of a plow-shaped cutting element of the disclosure mounted to a body of an earth-boring tool;

(3) FIG. 1A is a top perspective view of the plow-shaped cutting element;

(4) FIG. 1B is a front perspective view of the plow-shaped cutting element;

(5) FIG. 1C is a side perspective view of the plow-shaped cutting element;

(6) FIG. 2 is a schematic top plan view of profiles of two generally cylindrical cutting elements oriented at an acute angle relative to one another, and overlapping one another;

(7) FIG. 3 is similar to FIG. 2 and illustrates a cutting element like that of FIGS. 1A-1C overlying the profiles of the two generally cylindrical cutting elements shown in FIG. 2;

(8) FIG. 4A is a perspective view of an embodiment of a fixed-cutter earth-boring rotary drill bit of the disclosure that may include plow-shaped cutting elements as described herein;

(9) FIG. 4B is a plan view of a leading face of the drill bit shown in FIG. 4A; and

(10) FIG. 4C is a cutting element profile of the drill bit shown in FIGS. 4A and 4B.

DETAILED DESCRIPTION

(11) The illustrations presented herein are not actual views of any particular earth-boring tool, cutting element, or component thereof, but are merely idealized representations that are employed to describe embodiments of the present disclosure.

(12) As used herein, the term earth-boring tool means and includes any tool used to remove formation material and form a bore (e.g., a wellbore) through the formation by way of the removal of the formation material. Earth-boring tools include, for example, rotary drill bits (e.g., fixed-cutter or drag bits and roller cone or rock bits), hybrid bits including both fixed cutters and roller elements, coring bits, percussion bits, bi-center bits, reamers (including expandable reamers and fixed-wing reamers), and other so-called hole-opening tools.

(13) FIGS. 1A-1C illustrate an example embodiment of a plow-shaped cutting element 100 of the present disclosure. The plow-shaped cutting element 100 includes a superabrasive material 102, such as polycrystalline diamond or polycrystalline cubic boron nitride, disposed on one or more surfaces of a substrate 104. The superabrasive material 102 may be formed on the surfaces of the substrate 104 using a high temperature, high pressure (HTHP) process, or the superabrasive material 102 may be formed separately from the substrate 104 and subsequently bonded to the substrate 104. The substrate 104 may comprise a wear-resistant material, such as, for example, a cemented carbide material (e.g., cobalt-cemented tungsten carbide). In some embodiments, the substrate 104 may have a tapered geometry extending away from the outer lateral periphery of the superabrasive material 102, which may define a cutting edge of the cutting element 100, and toward a central longitudinal axis of the cutting element 100.

(14) The superabrasive material 102 may comprise a first layer 106A or table of the superabrasive material 102 and a second layer 106B of the superabrasive material 102, although the first and second layers 106A, 106B may be different regions of a single, unitary body of the superabrasive material 102 in some embodiments. The first layer 106A has a first generally planar front cutting face 107A, and the second layer 106B has a second generally planar front cutting face 107B. The generally planar front cutting surfaces 107A, 107B are oriented at an angle relative to one another such that they are not coplanar, but intersect one another along an apex 108 therebetween and are coextensive with one another. The apex 108 may be linear (e.g., not curved).

(15) Each surface 107A, 107B may have a shape comprising a portion of a circle or an oval, and may have a shape comprising more than 50% of a circle or an oval. In this configuration, as shown in FIG. 1B, the length L of the apex 108 extending along the intersection between the surfaces 107A, 107B may be less than the maximum diameters D of the circles or ovals of the surfaces 107A, 107B. In some embodiments, the length L of the apex 108 may be about 95% or less of each of the maximum diameters D of the surfaces 107A, 107B, about 90% or less of each of the maximum diameters D of the surfaces 107A, 107B, or even about 85% or less of each of the maximum diameters D of the surfaces 107A, 107B. The first and second surfaces 107A, 107B may be identical or they may be different in size, shape, and/or orientation (e.g., angle relative to a longitudinal axis of the cutting element 100).

(16) In this configuration, the cutting element 100 may include a concave notch 111 on opposing sides of the cutting element 100. The notches 111 may extend longitudinally along the cutting element 100 in the lateral side surfaces of the volume of superabrasive material 102 and in the lateral side surfaces of the substrate 104.

(17) In some embodiments, the first and second layers 106A, 106B of the superabrasive material 102 may be generally planar and may have an at least substantially constant layer thickness. In other embodiments, the first and second layers 106A, 106B may not be planar, and may have a varying layer thickness.

(18) Referring to FIG. 2, the cutting element 100 may be characterized as having a design attained by defining two generally cylindrical cutting elements 200A, 200B each having a longitudinal axis A.sub.L, orienting the two generally cylindrical cutting elements 200A, 200B at an acute angle relative to one another (i.e., orienting the two generally cylindrical cutting elements 200A, 200B such that an angle 202 between the longitudinal axes A.sub.L is between about ten degrees and about eighty degrees, or even between about ten degrees and about forty degrees (e.g., about twenty degrees) (20), and partially overlapping the two generally cylindrical cutting elements 200A, 200B. The generally cylindrical cutting elements 200A, 200B may be identical in shape to one another, or they may be different. In some embodiments, the generally cylindrical cutting elements 200A, 200B may be at least substantially cylindrical, such that the lateral side surfaces of the cutting elements 200A, 200B have a substantially cylindrical shape. In other embodiments, the generally cylindrical cutting elements 200A, 200B may have a tapered geometry, such that the lateral side surfaces of the cutting elements 200A, 200B have a frustoconical shape.

(19) FIG. 3 illustrates the cutting element 100 of FIGS. 1A-1C overlapping the profiles of the generally cylindrical cutting elements 200A, 200B of FIG. 2. As shown in FIG. 3, the cutting element 100 comprises a first half 110A and a second half 110B that meet along a plane 300. In some embodiments, the cutting element 100 may be symmetrical about the plane 300. In other embodiments, the cutting element 100 may be asymmetrical about the plane 300. Each of the two halves 110A, 110B may comprise a portion of a generally cylindrical cutting element (like the cutting elements 200A, 200B) oriented at an acute angle relative to the plane 300 (i.e., the acute angle between the respective longitudinal axes A.sub.L and the plane 300. Thus, a longitudinal axis A.sub.L may be defined for each of the two halves 110A, 110B, which extends along what would be the longitudinal centerline of a generally cylindrical cutting element (like the cutting elements 200A, 200B of FIG. 2), a portion of which defines the respective half 110A, 110B.

(20) Thus, the front cutting surfaces 107A, 107B of each of the layers 106A, 106B of the superabrasive material 102 may have a diameter D (FIG. 1B) that intersects the respective longitudinal axis A.sub.L on the exposed front cutting surfaces 107A, 107B of the generally planar layers 106A, 106B at points P (FIG. 3).

(21) In additional embodiments, the plane 300 may not be disposed along a centerline of the cutting element 100, and the cutting element 100 may not be asymmetric about the plane 300 as previously mentioned.

(22) As previously mentioned, the generally planar front cutting surfaces 107A, 107B are oriented at an angle relative to one another. By way of example and not limitation, an angle between the front cutting surfaces 107A, 107B may be between 90 and about 180, between about 115 and about 175, or even between about 130 and about 165.

(23) The cutting element 100 may be fabricated as a single unitary body in some embodiments. In other embodiments, each of the halves 110A, 110B of the cutting element 100 may be separately fabricated from one another and subsequently joined together using, for example, a welding, brazing, sintering, or other bonding process.

(24) The interface between the superabrasive material 102 and the substrate 104 may be tailored for specific performance parameters based on the anticipated drilling application and the expected loads to be applied to the cutting element 100. The geometry of the interface between the superabrasive material 102 and the substrate 104 could be planar, or it could have a three-dimensional geometry tailored to withstand reduce stresses within the cutting element 100 at the interface.

(25) If it is desired to maintain efficient drilling when the cutting element 100 is in a worn condition, the thickness of the superabrasive material 102 may be reduced (e.g., minimized) and may generally conform to the contour of the underlying surface of the substrate 104. In instances where the cutting element 100 is expected to be subjected to high impacts or loads, it may be desirable to provide a relatively thicker layer of the superabrasive material 102 on the substrate 104. Additionally, the thickness of the superabrasive material 102 could vary as previously mentioned. For example, the superabrasive material 102 could have a maximum thickness at the apex 108, and the thickness may decrease in directions extending from the apex 108 to the lateral sides of the cutting element 100.

(26) Embodiments of cutting elements 100 as described herein with reference to FIGS. 1A-1C and FIG. 3 may be mounted to bodies of earth-boring tools. For example, a fixed-cutter earth-boring rotary drill bit may be equipped with one or more cutting elements 100. As a non-limiting example, FIGS. 4A-4C illustrate a fixed-cutter earth-boring rotary drill bit 400 that may include one or more cutting elements 100. The drill bit 400 shown in FIGS. 4A-4C is a coring bit, and embodiments of cutting elements 100 as described herein may find particular utility in coring bits, although embodiments of the disclosure are not limited to such coring bits.

(27) The coring drill bit 400 of FIGS. 4A-4C includes a body 404, which includes a plurality of blades 406. Fluid courses 408 are defined between the blades 406. A generally cylindrical void 410 is defined at the center of the body 404, such that, as the drill bit 400 drills through a subterranean formation, a generally cylindrical core of the formation extends into the void 410. The generally cylindrical core may be broken off and brought to the surface of the formation for testing and/or analysis, as known in the art.

(28) FIG. 4C illustrates a cutting element profile of the drill bit 400. The cutting element profile illustrates the position of each of the cutting elements 402 rotated into a single plane. As is common in the industry, each cutting element is given an identifying number by consecutively numbering the cutting elements starting with the cutting element closest to the longitudinal centerline of the drill bit being numbered 1, the next closing cutting element 402 to the longitudinal centerline being numbered 2, and continuing in this manner for each of the cutting elements 402 moving radially outward away from the longitudinal centerline of the drill bit 400. As shown in FIG. 4C, the drill bit 400 includes forty-seven (47) cutting elements. Redundant cutting elements 402 may be disposed at the same radial position at some points along the cutting element profile. For example, as shown in FIG. 4C, cutting elements 1 through 6 are disposed at the same radial position and are redundant with one another. As shown in FIG. 4B, these cutting elements 1 through 6 are the cutting elements 402 located on the body 404 adjacent the central void 410, and are the cutting elements 402 that cut and define the formation core that will extend into the void 410 during drilling. In accordance with some embodiments of the present disclosure, one or more of these cutting elements 1 through 6 may comprise a cutting element 100 as described herein.

(29) FIGS. 1A-1C illustrate a cutting element 100 mounted on a blade 406 of such a drill bit 400 adjacent a void 410. The cutting element 100 may be mounted such that the apex 108 extends radially outwardly from the surface of the blade 406 surrounding the cutting element 100. In some embodiments, the cutting element 100 may be oriented such that the apex 108 is at least substantially perpendicular to the surface of the blade 406 surrounding the cutting element 100. For example, the cutting element 100 may be oriented such that the apex 108 is within about five degrees (5) of perpendicular to the surface of the blade 406 surrounding the cutting element 100, not considering back or forward rake angle of the cutting element 100. Referring to FIG. 1B, in this orientation, the lateral side portion 112 of the periphery 114 of front cutting surface 107B of the second layer 106B remote from the apex 108 will provide the cutting edge that cuts and defines the core of the formation that will extend into the void 410 during drilling. This lateral cutting edge will have an effective back rake angle relative to the core due, at least in part, to the angle of the front cutting surface 107B of the second layer 106B. The top portions 116 of the peripheries 114 of the first and second generally planar surfaces 107A, 107B of the layers 106A, 106B (from the perspective of FIG. 1B) will cut the formation in the path of the drill bit 400 (FIGS. 4A-4C), thereby allowing the drill bit 400 to advance further into the formation during drilling. These top cutting edges will have an effective side rake angle relative to the formation due, at least in part, to the angle of the front cutting surfaces 107A, 107B of the layers 106A, 106B relative to the direction of movement of the cutting element 100 during drilling.

(30) The geometry of the plow-shaped cutting elements 100 described herein may deflect formation cuttings away from the cutting elements 100 and into the fluid courses 408 of the drill bit 400 in an efficient manner. Additionally, the wear flat(s) that develop on the plow-shaped cutting elements 100 during drilling may be relatively smaller compared to at least some previously known cutting elements due, at least in part, to the geometry of the cutting elements 100, which may improve the performance of drill bits including such cutting elements 100 in at least some applications. In coring bits, the cutting elements 100 may be used to provide efficient cutting of the formation core when the cutting elements 100 are located in relatively convenient locations on the blades 406 at which conventional cutting elements may not be capable of providing equally efficient cutting of the formation core.

(31) Cutting elements 100 as described herein may be employed on any other type of earth-boring tool, in addition to fixed-cutting coring bits.

(32) Additional non-limiting embodiments of the disclosure are set forth below.

Embodiment 1

(33) A cutting element for an earth-boring tool, comprising: a substrate; and at least one volume of superabrasive material on the substrate, the at least one volume of superabrasive material including a first planar surface and a second planar surface oriented at an angle relative to the first planar surface and intersecting the first planar surface along an apex; wherein the first planar surface has a circular or oval shape having a first maximum diameter, the second planar surface has a circular or oval shape having a second maximum diameter, and the apex has a length less than the first maximum diameter and the second maximum diameter.

Embodiment 2

(34) The cutting element of Embodiment 1, wherein the superabrasive material comprises at least one of polycrystalline diamond and cubic boron nitride.

Embodiment 3

(35) The cutting element of Embodiment 1 or Embodiment 2, wherein the at least one volume of superabrasive material comprises: a first layer of superabrasive material on a first region of the substrate; and a second layer of superabrasive material on a second region of the substrate.

Embodiment 4

(36) The cutting element of Embodiment 3, wherein the first layer of superabrasive material and the second layer of superabrasive material are integral portions of a single volume of the superabrasive material.

Embodiment 5

(37) The cutting element of any one of Embodiments 1 through 4, wherein the apex is linear.

Embodiment 6

(38) The cutting element of any one of Embodiments 1 through 5, wherein the length of the apex is about 95% or less of each of the first maximum diameter and the second maximum diameter.

Embodiment 7

(39) The cutting element of Embodiment 6, wherein the length of the apex is about 90% or less of each of the first maximum diameter and the second maximum diameter.

Embodiment 8

(40) The cutting element of Embodiment 7, wherein the length of the apex is about 85% or less of each of the first maximum diameter and the second maximum diameter.

Embodiment 9

(41) The cutting element of any one of Embodiments 1 through 8, wherein the angle between the first planar surface and the second planar surface is between 90 and about 180.

Embodiment 10

(42) The cutting element of Embodiment 9, wherein the angle between the first planar surface and the second planar surface is between about 115 and about 175.

Embodiment 11

(43) The cutting element of Embodiment 10, wherein the angle between the first planar surface and the second planar surface is between about 130 and about 165.

Embodiment 12

(44) An earth-boring tool, comprising: a body; and at least one cutting element as recited in any one of Embodiments 1 through 11 attached to the body.

Embodiment 13

(45) The earth-boring tool of Embodiment 12, wherein the earth-boring tool comprises a fixed-cutter rotary drill bit.

Embodiment 14

(46) The earth-boring tool of Embodiment 13, wherein the fixed-cutter rotary drill bit comprises a coring bit having a generally cylindrical void defined at a center of the body.

Embodiment 15

(47) The earth-boring tool of Embodiment 14, wherein the at least one cutting element is attached to the body at a location adjacent the generally cylindrical void, the at least one cutting element located and configured such that a lateral cutting edge of the at least one cutting element defined at a periphery of one of the first planar surface and the second planar surface remote from the apex will cut and define a core sample of a formation when the coring bit is used to drill through the formation.

Embodiment 16

(48) A method of forming an earth-boring tool, comprising: selecting at least one cutting element to comprise a cutting element as recited in any one of Embodiments 1 through 11, and attaching the at least one cutting element to a body of an earth-boring tool.

Embodiment 17

(49) A method of forming a cutting element as recited in any one of Embodiments 1 through 11.

(50) Although the foregoing description contains many specifics, these are not to be construed as limiting the scope of the present invention, but merely as providing certain embodiments. Similarly, other embodiments of the invention may be devised which do not depart from the scope of the present invention. For example, features described herein with reference to one embodiment also may be provided in others of the embodiments described herein. The scope of the invention is, therefore, indicated and limited only by the appended claims and their legal equivalents, rather than by the foregoing description. All additions, deletions, and modifications to the invention, as disclosed herein, which fall within the meaning and scope of the claims, are encompassed by the present invention.