CUTTER GEOMETRY UTILIZING SPHERICAL CUTOUTS

Abstract

A cutting element comprising a polycrystalline diamond table having a first end attached to a substrate at an interface. The second end of the diamond table includes a concave surface, concave indentations, cutting edges at an interface between the concave surface and an outer diameter of the diamond table. Each of the at least two concave indentations intersects the concave surface and extends radially outward from the concave surface to an outer diameter of the diamond table. A method of manufacturing an earth-boring downhole tool includes providing a tool body and securing to the tool body the cutting element as recited in any one of the claims.

Claims

1. A cutting element, comprising: a substrate; and a diamond table having a first end and a second end, the first end of the diamond table affixed to the substrate at a first interface, the second end of the diamond table comprising: a concave surface; at least two concave indentations, each of the at least two concave indentations intersecting the concave surface and extending radially outward from the concave surface to an outer diameter of the diamond table; and at least two cutting edges at an interface between the concave surface and the outer diameter of the diamond table.

2. The cutting element of claim 1, wherein the concave surface has a radius of curvature between 5 millimeters and 250 millimeters.

3. The cutting element of claim 1, wherein the concave surface covers between 10% and 90% of a total surface area of the second end of the diamond table.

4. The cutting element of claim 1, wherein the concave surface and/or the at least two concave indentations each respectively define a portion of a sphere.

5. The cutting element of claim 1, wherein each of the at least two concave indentations has a radius of curvature that is between 5 millimeters and 125 millimeters.

6. The cutting element of claim 1, wherein each of the at least two concave indentations extends into the diamond table to a depth of up to 95% of a thickness of the diamond table.

7. The cutting element of claim 1, wherein the at least two concave indentations do not merge into each other.

8. The cutting element of claim 1, wherein each of the at least two concave indentations are spaced equidistantly from each other around the outer diameter of the diamond table.

9. The cutting element of claim 1, wherein the at least two cutting edges are chamfered.

10. The cutting element of claim 1, wherein the at least two concave indentations comprise three concave indentations.

11. The cutting element of claim 10, wherein each of the three concave indentations do not merge into each other.

12. The cutting element of claim 10, wherein each of the three concave indentations are spaced equidistantly from each other around the outer diameter of the diamond table.

13. A method of manufacturing an earth-boring downhole tool, the method comprising: securing the cutting element of claim 1 to a tool body.

14. The method of claim 13, further comprising forming the concave surface and/or the at least two concave indentations by grinding.

15. The method of claim 13, further comprising forming the concave surface and/or the at least two concave indentations by Electro Discharge Machining (EDM).

16. The method of claim 13, further comprising forming the concave surface and/or the at least two concave indentations by laser removal.

17. The cutting element of claim 1, wherein the concave surface extends into the diamond table to a depth of up to 25% of a thickness of the diamond table.

18. The cutting element of claim 1, further comprising a chamfered edge along a periphery of the diamond table.

19. The cutting element of claim 18, wherein the chamfered edge has a constant width.

20. The cutting element of claim 1, wherein the concave indentations are on opposite sides of the concave surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 illustrates a prior art conventional cylindrical PDC cutting element having a conventional cylindrical planar front cutting face.

[0029] FIG. 2 illustrates a PDC cutting element, in accordance with one embodiment. The PDC cutting element has a concave surface, two cutting edges, and two concave indentations that intersect the concave surface and extend radially outward from the concave surface to an outer diameter of the diamond table.

[0030] FIG. 3 illustrates a PDC cutting element, in accordance with one embodiment. The PDC cutting element has a concave surface, three cutting edges, and three concave indentations that intersect the concave surface and extend radially outward from the concave surface to an outer diameter of the diamond table.

DETAILED DESCRIPTION

[0031] The illustrations presented herein are not actual views of any particular cutting assembly, tool, or drill string, but are merely idealized representations employed to describe example embodiments of the present disclosure. The following description provides specific details of embodiments of the present disclosure in order to provide a thorough description thereof. However, a person of ordinary skill in the art will understand that the embodiments of the disclosure may be practiced without employing many such specific details. Indeed, the embodiments of the disclosure may be practiced in conjunction with conventional techniques employed in the industry. In addition, the description provided below does not include all elements to form a complete structure or assembly. Only those process acts and structures necessary to understand the embodiments of the disclosure are described in detail below. Additional conventional acts and structures may be used. The drawings accompanying the application are for illustrative purposes only, and are not drawn to scale. Additionally, elements common between figures may have corresponding numerical designations.

[0032] As used herein, the terms “comprising,” “including,” “containing,” “characterized by,” and grammatical equivalents thereof are inclusive or open-ended terms that do not exclude additional, unrecited elements or method steps, but also include the more restrictive terms “consisting of” and “consisting essentially of” and grammatical equivalents thereof.

[0033] As used herein, the term “may” with respect to a material, structure, feature, or method act indicates that such is contemplated for use in implementation of an embodiment of the disclosure, and such term is used in preference to the more restrictive term “is” so as to avoid any implication that other compatible materials, structures, features and methods usable in combination therewith should or must be excluded.

[0034] As used herein, the term “configured” refers to a size, shape, material composition, and arrangement of one or more of at least one structure and at least one apparatus facilitating operation of one or more of the structure and the apparatus in a predetermined way.

[0035] As used herein, the singular forms following “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0036] As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

[0037] As used herein, relational terms, such as “first,” “second,” “top,” “bottom,” etc., are generally used for clarity and convenience in understanding the disclosure and accompanying drawings and do not connote or depend on any specific preference, orientation, or order, except where the context clearly indicates otherwise.

[0038] As used herein, the term “substantially” in reference to a given parameter, property, or condition means and includes to a degree that one of ordinary skill in the art would understand that the given parameter, property, or condition is met with a degree of variance, such as within acceptable manufacturing tolerances. By way of example, depending on the particular parameter, property, or condition that is substantially met, the parameter, property, or condition may be at least 90.0% met, at least 95.0% met, at least 99.0% met, or even at least 99.9% met.

[0039] As used herein, the term “about” used in reference to a given parameter is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the given parameter).

[0040] As used herein, the term “earth-boring tool” means and includes any type of bit or tool used for drilling during the formation or enlargement of a wellbore and includes, for example, rotary drill bits, percussion bits, core bits, eccentric bits, bi-center bits, reamers, mills, drag bits, roller-cone bits, hybrid bits, and other drilling bits and tools known in the art.

[0041] Improvements in the flow characteristics of cutting elements along with improvements in the cutting element efficiency and durability of cutting elements may be achieved in accordance with embodiments of the present disclosure. Downhole earth-boring tools, comprising cutting elements having novel geometries for improved flow characteristics and mechanical efficiency are described in further detail hereinbelow.

[0042] FIGS. 2A, 2B, and 2C illustrate a face view and two side views respectively of an embodiment of a PDC cutting element 200 in accordance with the present disclosure. In this embodiment, the PDC cutting element 200 comprises a diamond table 212 bonded to a substrate 210 at an interface 214. FIGS. 2A, 2B, and 2C further illustrate three concave subtractions or cutouts that have been taken from diamond table 212 thus defining a concave surface 202 and two concave indentations 216.

[0043] The concave surface 202 forms more aggressive cutting edges 206 than the prior art planar front cutting face 108 illustrated in FIGS. 1A, 1B, and 1C and much more aggressive cutting edges 206 than the prior art domed surfaces described in the background section. As described in the background section, a cutting face having a concave surface is typically not used in the industry because the concave surface directs drilling fluid and cuttings back towards the center of the cutting element creating issues with bit balling and fluid flow. However, in the embodiment illustrated in FIGS. 2A, 2B, and 2C, the concave surface 202 is used in conjunction with the concave indentations 216 that cause drilling fluid and cuttings to flow away from the center of the PDC cutting element 200. Thus, the concave surface 202 creates more aggressive cutting edges 206 and the concave indentations 216 improve flow characteristics around the cutting edges 206. These improvements in the geometry of PDC cutting element 200 may improve the Rate of Penetration (ROP) while reducing heat, abrasion, and bit balling at the drilling face of the drill bit.

[0044] FIGS. 2A and 2C illustrates a concave surface 202 that is symmetric about line 220 and extends across the diamond table 212 from one side of the PDC cutting element 200 to the opposite side of the PDC cutting element 200, forming a dish-like top surface 218 into the diamond table 212. In some embodiments, the radius of curvature of the concave surface may be between about 10 millimeters and 250 millimeters. In some embodiments, the concave surface may define a portion of a sphere. In some embodiments, the concave surface 202 may comprise between about 10% and 90% of the overall surface area of the diamond table 212 and may extend down into as much as 25% of the thickness of the diamond table 212. In some embodiments, the concave subtraction (or cutout) process may use grinding, milling, laser machining, or any other suitable method known in the art to remove diamond material from the diamond table 212 to form the concave surface 202 and the concave indentations 216 in the diamond table 212. Two cutting edges 206 are disposed at an interface between the concave surface 202 and the outer diameter or longitudinal side surface 208 of the PDC cutting element 200.

[0045] In drilling a borehole, the optimal orientation for PDC cutting element 200 is to have one of the cutting edges 206 of the concave surface 202 oriented towards the formation material to be drilled. When significant wear has worn down the first of the cutting edges 206 of the PDC cutting element 200, the PDC cutting element 200 may be reoriented by removing the drill bit, and by removing, rotating, and reattaching the PDC cutting element 200 on the drill bit to orient the second of the cutting edges 206 towards the formation material.

[0046] FIG. 2A also illustrates two concave indentations 216 that form two edges of the concave surface 202 and extend from the concave surface 202 radially outward to an outer diameter or longitudinal side surface 208 of the diamond table 212. As illustrated in FIGS. 2A, 2B, and 2C, the two concave indentations 216 may be formed into the diamond table 212 on opposite sides of the concave surface 202, intersecting the diamond table 212 and extending radially to an outside diameter of the PDC cutting element 200. The concave indentations 216 may also symmetric with respect to line 220, which is illustrated in FIG. 2A running vertically across a center of the concave surface 202. In some embodiments, the concave indentations may each define a portion of a sphere. In some embodiments, the two concave indentations 216 may be formed into the diamond table 212 at other locations, may be adjacent to each other, and may overlap and/or merge into each other. In some embodiments, the concave indentations 216 may extend into as much as 95% of the thickness of the diamond table 212. In some embodiments, the radius of curvature between of the concave surface may be between about 5 millimeters and 125 millimeters.

[0047] FIGS. 2A, 2B, and 2C also illustrate a chamfered edge 204 along at least a portion of the cutting edges 206, and between the concave indentations 216 and the outer diameter of the diamond table (or longitudinal side surface 208 of the PDC cutting element 200). The chamfered edge 204 illustrated in the figures has a constant width around the circumference of PDC cutting element 200. As described above, a chamfered edge 204 has been found to reduce the tendency of the diamond table 212 to spall and fracture.

[0048] The order in which the concave subtractions are formed does not matter. The concave indentations 216 could be formed before or after the concave surface 202, or all of the concave subtractions could be formed in a substantially simultaneous fashion.

[0049] FIGS. 3A, 3B, and 3C illustrate perspective, face, and side views respectively of an embodiment of a PDC cutting element 300, in accordance with the present disclosure, in which four concave subtractions or cutouts have been taken from diamond table 304, thus defining three concave indentations 308 and a concave surface 302. The concave indentations 308 form three edges of the concave surface 302 and extend from the concave surface 302 radially outward to an outer diameter of the diamond table 304 (or longitudinal side surface 314 of the PDC cutting element 200).

[0050] In some embodiments, the PDC cutting element 300 comprises a diamond table 304 bonded to a substrate 306 at an interface 312. In some embodiments, the total thickness of the diamond table 304 may be between 1 mm and 10 mm, more preferably between 2 mm and 5 mm, more preferably about 3 mm to 3.5 mm.

[0051] As illustrated in FIGS. 3A and 3B, the top surface of the diamond table 304 comprises a concave surface 302, three concave indentations 308, and three cutting edges 310. The three concave indentations 308 extend from a concave surface 302 that is roughly triangular with curved edges. In some embodiments, the concave surface may define a portion of a sphere. FIGS. 3A, 3B, and 3C, also illustrate three concave indentations 308 that are spaced equidistantly from each other around an outer edge of the diamond table and do not meet or merge into each other. In some embodiments, the concave indentations 308 may not be spaced equidistantly from each other around an outer edge of the diamond table and may meet or merge into each other. In some embodiments, there may be four or more concave indentations. In some embodiments, the concave indentations 308 may extend into as much as 95% of the thickness of the diamond table 304. In some embodiments, the concave indentations may each define a portion of a sphere.

[0052] As illustrated in FIG. 3B, the concave surface 302 is symmetric about line 318 and extends from one side of the diamond table 304 to the opposite side of the diamond table. In the embodiment illustrated in FIGS. 3A, 3B, and 3C, the concave surface 302 is concave or dish-like. In some embodiments, concave surface 302 may extend to the outer diameter or longitudinal side surface 314 of the PDC cutting element 300. The concave surface 302 may comprise between about 10% and 90% of the overall surface area of the diamond table 304 and may extend down into as much as 25% of the thickness of the diamond table 304.

[0053] As described above, the concave indentations 308 and the concave surface 302 may be formed in the diamond table 304 by grinding, machining, milling, or any other suitable method known in the art to remove polycrystalline diamond material. Furthermore, the order in which the concave subtractions are formed does not matter. The grinding, milling, or machining, etc., to form the concave subtraction surfaces may be done in any order, or the surfaces may be formed substantially simultaneously.

[0054] FIGS. 3A, 3B, and 3C, also illustrate three cutting edges 310 disposed at an interface between the concave surface 302 and the outer diameter of the diamond table 304 (or longitudinal side surface 314 of the PDC cutting element 300). When forming a borehole, the optimal orientation for PDC cutting element 300 is to have one of the cutting edges 310 oriented (or pointed) towards the formation material to be drilled. When significant abrasion has worn down a first of the cutting edges 310 of the PDC cutting element 300, the PDC cutting element 300 may be rotated by removing the drill bit, and by removing, rotating, and reattaching the PDC cutting element 300 on the drill bit in order to orient a second (and then a third etc.) of the cutting edges 310 towards the formation material to be drilled. The concave indentations 308 may be configured and oriented to improve the flow of the drilling fluid and formation cuttings around the face of the PDC cutting element 300.

[0055] FIGS. 3A, 3B, and 3C also illustrates a chamfered edge 316 along at least a portion of the cutting edges 310, and between the concave indentations 308 and the outer diameter of the diamond table 304 (or longitudinal side surface 314 of the PDC cutting element 300). The chamfered edge 316 illustrated in the figures has a uniform width around the circumference of the PDC cutting element 300. As described above, a chamfered edge 316 has been found to reduce the tendency of the diamond table 304 to spall and fracture.

[0056] Computer modeling indicates that the concave surface 302 with concave indentations 308, will cut more efficiently and improve flow characteristics around the cutting element and the drill bit. It is expected that, drill bits having cutting elements with this improved geometry may require less torque and less weight on the bit than other prior art bits to achieve a similar Rate of Penetration (ROP). Therefore, it is expected that the concave cutting surface will last longer and be more durable than prior art bits.

[0057] The embodiments of the disclosure described above and illustrated in the accompanying drawing figures do not limit the scope of the invention, since these embodiments are merely examples of embodiments of the invention, which is defined by the appended claims and their legal equivalents. Any equivalent embodiments are intended to be within the scope of this disclosure. Indeed, various modifications of the present disclosure, in addition to those shown and described herein, such as alternative useful combinations of the elements described, may become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims and their legal equivalents.

[0058] In exemplary embodiments, a typical rotary-type “drag” bit made from steel and using PDC cutting elements is described. Those skilled in the art, however, will appreciate that the size, shape, and/or configuration of the bit may vary according to operational design parameters without departing from the spirit of the present invention. Further, the invention may be practiced on non-rotary drill bits, the invention having applicability to any drilling-related structure including percussion, impact or “hammer” bits. It will also be appreciated by one of ordinary skill in the art that one or more features of any of the illustrated embodiments may be combined with one or more features from another embodiment to form yet another combination within the scope of the invention as described and claimed herein. Thus, while certain representative embodiments and details have been shown for purposes of illustrating the invention, it will be apparent to those skilled in the art that various changes in the invention disclosed herein may be made without departing from the scope of the invention, which is defined in the appended claims.

[0059] Additional non-limiting example embodiments of the disclosure are described below.

[0060] Embodiment 1: A cutting element comprising a substrate and a diamond table wherein the diamond table has a first end and a second end. The first end of the diamond table is affixed to the substrate at a first interface. The second end of the diamond table comprises a concave surface, at least two concave indentations, and at least two cutting edges at an interface between the concave surface and an outer diameter of the diamond table. Each of the at least two concave indentations intersects the concave surface and extends radially outward from the concave surface to the outer diameter of the diamond table.

[0061] Embodiment 2: The cutting element of Embodiment 1, wherein the concave surface has a radius of curvature between 5 millimeters and 250 millimeters.

[0062] Embodiment 3: The cutting element of Embodiment 1 or Embodiment 2, wherein the concave surface covers between 10% and 90% of a total surface area of the second end of the diamond table.

[0063] Embodiment 4: The cutting element of any of Embodiments 1 through 3, wherein the concave surface and/or the concave indentations each respectively define a portion of a sphere.

[0064] Embodiment 5: The cutting element of any of Embodiments 1 through 4, wherein each of the at least two concave indentations has a radius of curvature that is between 5 millimeters and 125 millimeters.

[0065] Embodiment 6: The cutting element of any of Embodiments 1 through 5, wherein each of the at least two concave indentations extends into the diamond table to a depth of up to 95% of a thickness of the diamond table.

[0066] Embodiment 7: The cutting element of any of Embodiments 1 through 6, wherein the at least two concave indentations do not merge into each other.

[0067] Embodiment 8: The cutting element of any of Embodiments 1 through 7, wherein each of the at least two concave indentations are spaced equidistantly from each other around the outer diameter of the diamond table.

[0068] Embodiment 9: The cutting element of any of Embodiments 1 through 8, wherein the at least two cutting edges are chamfered.

[0069] Embodiment 10: The cutting element of any of Embodiments 1 through 9, wherein the at least two concave indentations comprise three concave indentations.

[0070] Embodiment 11: The cutting element of any of Embodiments 1 through 10, wherein each of the at least three concave indentations do not merge into each other.

[0071] Embodiment 12: The cutting element of any of Embodiments 1 through 11, wherein each of the at least three concave indentations are spaced equidistantly from each other around the outer diameter of the diamond table.

[0072] Embodiment 13: A method of manufacturing an earth-boring downhole tool comprising: providing a tool body and securing to the tool body, the cutting element, as recited in any one of claims 1 through 12.

[0073] Embodiment 14: The method of any of Embodiments 1 through 13, further comprising forming the concave surface and/or the at least two concave indentations by grinding.

[0074] Embodiment 15: The method of any of Embodiments 1 through 14, further comprising forming the concave surface and/or the at least two concave indentations by Electro Discharge Machining (EDM).

[0075] Embodiment 16: The method of any of Embodiments 1 through 15, further comprising forming the concave surface and/or the at least two concave indentations by laser removal.

[0076] The embodiments of the disclosure described above and illustrated in the accompanying drawing figures do not limit the scope of the invention, since these embodiments are merely examples of embodiments of the invention, which is defined by the appended claims and their legal equivalents. Any equivalent embodiments are intended to be within the scope of this disclosure. Indeed, various modifications of the present disclosure, in addition to those shown and described herein, such as alternative useful combinations of the elements described, may become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims and their legal equivalents.