Cutting elements with improved mechanical efficiency

Abstract

The present disclosure relates to a downhole tool including a bit body and a plurality of blades. Each blade has at least one cutting element disposed within the blade. Each cutting element includes a substrate and a polycrystalline diamond material attached to the substrate at an interface. The polycrystalline diamond material includes a raised cutting surface having at least two cutting edges, a recess at a center of the raised cutting surface, and a transition surface between the at least two cutting edges of the raised cutting surface and a side surface of the cutting element. The present disclosure also includes a method of manufacturing a downhole tool including forming a bit, a blade, and a cutting element. Forming the cutting element includes forming a raised cutting surface having at least two cutting edges, forming a recess at a center of the raised cutting surface, and forming a transition surface between the raised cutting surface and a side surface of the cutting element.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure generally relate to cutting elements for use on earth-boring tools during earth-boring operations. In particular, embodiments of the present disclosure relate to cutting elements having geometries for improved mechanical efficiency. BACKGROUND

[0002] Wellbores are formed in subterranean formations for various purposes, including, for example, the production of oil and gas from the subterranean formation and the production of geothermal energy from the subterranean formation. Earth-boring tools, such as earth-boring rotary drill bits, can be used to form wellbores in subterranean formations. The earth-boring rotary drill bits are rotated and advanced into the subterranean formation. As the earth-boring rotary drill bits are rotated, cutters or abrasive structures thereof cut, crush, shear, and / or abrade away formation material to form the wellbore.

[0003] The earth-boring rotary drill bits are directly or indirectly coupled to an end of what is referred to in the art as a "drill string," which includes a series of elongated tubular segments connected end-to-end that extend from the surface above the subterranean formation being drilled into the wellbore. Various tools and components, including the drill bit, can be coupled together at the distal end of the drill string at the bottom of the wellbore being drilled. This assembly of tools and components is referred to in the art as the "bottom hole assembly" (BHA).

[0004] The earth-boring rotary drill bits can be rotated within the wellbore by rotating the drill string from the surface of the formation; or the drill bits can be rotated by coupling the drill bit to a downhole motor coupled to the drill string and disposed proximate the bottom of the wellbore. The downhole motor can include, for example, a hydraulic Moineau-type motor having a shaft to which the earth-boring rotary drill bit is mounted, which can be caused to rotate by pumping fluid (e.g., drilling mud or drilling fluid) down through the center of the drill string from the surface of the formation, through the hydraulic motor, out of nozzles in the drill bit, and up through an annular space between the outer surface of the drill string and the exposed surface of the formation within the wellbore to the surface of the formation. The downhole motor can be operated with or without rotation of the drill string.

[0005] Different types of earth-boring rotary drill bits are known in the art, including fixed-cutter drill bits, rolling-cutter drill bits, and hybrid drill bits (which can include, for example, both fixed cutters and rolling cutters). In contrast to roller cone drill bits, fixed-cutter drill bits have no moving parts and are designed to rotate about the longitudinal axis of the drill string. Most fixed-cutter drill bits employ polycrystalline diamond compact (PDC) cutting elements. The cutting edges of the PDC cutting elements drill rock formations by shearing in a cutting action like that of a lathe, as opposed to roller cone drill bits, which drill by dishing and crushing rock. The cutting action of the cutting edges plays a major role in the amount of energy required to drill rock formations.

[0006] PDC cutting elements are typically constructed of a thin layer (about 3.5 mm) of polycrystalline diamond material bonded to a cutting element substrate at an interface. The polycrystalline diamond material is commonly referred to as a "diamond table." PDC cutting elements are typically cylindrical in shape with diameters ranging from about 8 mm up to about 24 mm. However, PDC cutting elements can have other shapes, such as oval or triangular, and can be larger or smaller than the above-mentioned sizes.

[0007] PDC cutting elements can be fabricated independently of the drill bit body and secured within a cutting element pocket formed in the outer surface of a blade of the drill bit body. Bonding materials such as adhesives or, more typically, braze alloys can be used to secure the PDC cutting element within the pocket. The diamond table of a PDC cutting element is formed by sintering and bonding together relatively small diamond grains in the presence of a catalyst, such as, for example, cobalt, iron, nickel, or alloys and mixtures thereof, under high temperature and high pressure (HTHP) conditions to form a layer or "table" of polycrystalline diamond material on a cutting element substrate.

[0008] Figure 1A 、 Figure 1B and Figure 1C respectively show perspective, front, and side views of a conventional polycrystalline diamond compact (PDC) cutting element 100 of the prior art. A polycrystalline diamond table (diamond table) 104 is bonded to a substrate 106 at an interface 110. Prior to use, the PDC cutting element typically has a planar front cutting face 108 and a conventional cylindrical cutting edge 102. The planar front cutting face 108 is perpendicular to the longitudinal axis 112 of the cutting element 100 and is generally parallel to the interface 110 between the diamond cutting table 104 and the substrate 106. The cutting edge 102 of the PDC cutting element 100 is where the planar front cutting face 108 intersects the longitudinal side surface of the diamond table 104. The cutting edge 102 of the PDC cutting element 100 drills rock formations by shearing them (similar to the cutting action of a lathe). The cutting action of the cutting edge 102 plays a major role in the amount of energy required to drill rock formations. During use, as the cutting edge 102 of the PDC cutting element 100 wears, a wear scar is created at the cutting edge 102. Eventually, as the wear scar forms and develops, the cutting edge 102 in contact with the formation becomes linear. Figure 11A A wear scar 1106 is shown for a conventional PDC cutting element 1102.

[0009] The cutting element substrate 106 can comprise a cermet material (i.e., a ceramic metal composite), such as, for example, cobalt-cemented tungsten carbide. In this case, the cobalt (or other catalyst material) in the substrate 106 can be swept into the diamond grains during the sintering process and used as a catalyst material to form inter-grain diamond-diamond bonds between the diamond grains in the diamond table 104.

[0010] When diamond tables are formed using the HTHP method, catalyst material can remain in the interstitial spaces between the diamond table grains. When the cutting element 100 heats up during use, the presence of catalyst material in the diamond table can cause degradation of the diamond-diamond bonds between the diamond grains in the diamond table. The degradation of the diamond-diamond bonds due to heat is referred to as "thermal damage" to the diamond table 104. Thus, it is advantageous to minimize the amount of heat to which the cutting element 100 is exposed. This can be accomplished by reducing the rate of penetration of the earth boring rotary drill bit. However, a reduction in the rate of penetration means that the drilling process takes longer and is more costly, while failure of the cutting element 100 means that the drilling process has to be stopped to remove the drill string in order to replace the drill bit. Thus, there is a need for a cutting element that has improved rate of penetration and improved durability while reducing the buildup of heat at the cutting element.

[0011] One method of enhancing the durability of a PDC cutting element is to modify the cutting edge of the PDC cutting element to reduce stress points. One way of doing this is to form a tapered surface in the cylindrical side surface of the cutting element, as shown in Figure 2A 、 Figure 2B and Figure 2C . Figure 2A 、 Figure 2B and Figure 2C show a perspective view, an elevation view, and a side view of a prior art PDC cutting element 200. The PDC cutting element 200 includes a polycrystalline diamond table 204 and a substrate 206 bonded together at an interface 214. It is known in the industry to form a planar tapered surface 202 in the side surface of the PDC cutting element 200 adjacent the cutting face 212 and the cutting edge 208 of the cutting element 200.

[0012] Another method of increasing the efficiency and durability of the cutting element 200 is to form a chamfered edge 208 on the cutting edge 208 of the diamond table 204. It is known in the industry that chamfering the edge of a PDC cutting element 200 can enhance the durability of the PDC cutting element 200. It has been found that a diamond table 204 having a chamfered edge 210 on the cutting edge 208 has a reduced tendency to spall and fracture.

[0013] Multi-chamfered polycrystalline diamond compact (PDC) cutting elements are also known in the art. For example, U.S. Patent No. 5,437,343 to Cooley et al., which is assigned to the assignee of the present invention, teaches a multi-chamfered cutting element. In particular, the Cooley et al. patent discloses a PDC cutting element having a polycrystalline diamond material having two concentric chamfers.

[0014] It is also known in the industry that changing the shape of a diamond table can improve the efficiency and durability of a cutting element. U.S. Patent 5,333,699 to Thigpin et al. is directed to a cutting element having a spherical first end opposite a cutting end. Cutting element variations shown in FIGS. 22-29 of Thigpin et al. include channels or holes formed in the cutting face. U.S. Patent 9,598,909 to Patel is directed to a cutting element having grooves on the cutting face, as is Patel’s Figure 9 - FIG. 13.

[0015] U.S. Patent No. 4,109,737 to Bovenkerk is directed to a cutting element having a thin layer of polycrystalline diamond bonded to the free end of an elongated pin. One particular cutting element variation shown in FIG. 4G of Bovenkerk includes a generally hemispherical diamond layer having a plurality of flats formed on its outer surface.

[0016] U.S. Patent 10,378,289 to Stockey and U.S. Patent Publication U.S. 2017 / 0234078 Al to Patel et al. are directed to cutting faces of cutting elements having a plurality of chamfers forming concentric rings on the cutting face. One particular cutting element variation shown in FIG. 1 of Stockey includes an annular surface having chamfers around an annular groove at the cutting edge, which in turn surrounds a flat circle at the center of the cutting face. Another cutting element variation shown in FIG. 2 of Patel et al. includes a plurality of raised annular surfaces and a plurality of annular grooves surrounding a flat circle at the center of the cutting face.

[0017] U.S. Patent 6,196,340 to Jensen is directed to raised surface geometry on non-planar cutting elements. One variation shown in FIG. 4a of Jensen includes a four-sided pyramid shape having a flat square surface on the top.

[0018] U.S. Patent Publication 2018 / 0148978 Al to Chen is directed to a cutting element having a raised hexagonal shape. Another cutting element variation shown in FIG. 1 of Chen includes a raised hexagonal shape having chamfered edges. Figure 5A Another cutting element variation shown in FIG. 2 of Chen includes a raised hexagonal shape having six circular “teeth”. Figure 5C Another cutting element variation shown in FIG. 3 of Chen includes a raised cutting surface having six circular “teeth”.

[0019] U.S. Patent No. 8,783,387 to Durairajan et al. relates to cutting elements having high rate of penetration (ROP) geometry. One cutting element variation shown in FIGS. 4 and 5 of Durairajan et al. includes a cutting element having a shaped cutting surface that includes a raised triangular shape. Another cutting element variation shown in FIGS. 5 and 6 of Durairajan et al. includes a cutting element having a raised triangle with beveled or chamfered edges.

[0020] PCT Publication WO 2018 / 231343 to Cuillier De Maindreville et al. relates to superabrasive drill bits having a plurality of raised cutting surfaces. One cutting element variation shown in FIG. 1 of Cuillier De Maindreville et al. includes a raised triangular shape similar to Durairajan et al.

[0021] U.S. Patent No. 5,499,688 to Dennis relates to PDC cutting elements. Cutting element variations shown in FIGS. 7-11 of Dennis include cutting elements having various raised shapes including triangular and hexagonal shapes.

[0022] Cutting elements having raised surfaces and chamfered edges are known in the industry. However, these innovations do not address the heat issues associated with cutting elements and there remains a need for further improvements in reliability and durability of cutting elements. SUMMARY

[0023] In some embodiments, the present disclosure includes a cutting element for a drill earth tool for forming a borehole through an earthen formation. The cutting element includes a substrate and a polycrystalline diamond material affixed to the substrate at an interface. The polycrystalline diamond material includes a raised cutting surface having two cutting edges; a recess at a center of the raised cutting surface; and a transition surface between the two cutting edges of the raised cutting surface and a longitudinal side surface of the cutting element.

[0024] In some embodiments, the present disclosure includes a drill earth downhole tool for forming a borehole through an earthen formation. The drill earth tool includes a bit body and a plurality of blades extending from one end of the body. Each of the blades includes a leading edge portion; and at least one cutting element disposed within each blade proximate the leading edge portion of the blade. The at least one cutting element includes a substrate and a polycrystalline diamond material affixed to the substrate at an interface. The polycrystalline diamond material includes a raised cutting surface having three cutting edges, a recess at a center of the raised cutting surface, and a transition surface between the three cutting edges of the raised cutting surface and a longitudinal side surface of the cutting element.

[0025] In some embodiments, the present disclosure includes a method of manufacturing an earth-boring tool for forming a borehole through an earthen formation. The method includes forming at least one blade extending from one end of an earth-boring rotary drill bit body, wherein the at least one blade includes a leading edge portion. The method further includes forming at least one cutting element in the at least one blade proximate the leading edge portion of the blade. Wherein forming the at least one cutting element includes forming a polycrystalline diamond material, affixing a first end of the polycrystalline diamond material to a substrate at an interface, and shaping a second end of the polycrystalline diamond material. Wherein shaping the second end of the polycrystalline diamond material includes forming at least two cutting edges defining a raised cutting surface, forming at least one recess in a center of the raised cutting surface, and forming at least one transition surface between at least one of the at least two cutting edges defining the raised cutting surface and a longitudinal side surface of the cutting element. BRIEF DESCRIPTION OF DRAWINGS

[0026] FIG. 1 illustrates a prior art conventional cylindrical PDC cutting element having a conventional cylindrical planar leading cutting face.

[0027] FIG. 2 illustrates a prior art PDC cutting element having two planar tapered surfaces formed in a cylindrical side surface of the cutting element proximate a cutting face of the cutting element.

[0028] FIG. 3 illustrates a PDC cutting element having a raised cutting surface including two cutting edges, a recess in a center of the raised cutting surface, and a non-raised planar transition surface, according to one embodiment.

[0029] FIG. 4 illustrates a PDC cutting element having a raised cutting surface including three cutting edges, a recess in a center of the raised cutting surface, and a planar transition surface, according to one embodiment.

[0030] FIG. 5 illustrates a PDC cutting element having a raised cutting surface including three cutting edges, a recess in a center of the raised cutting surface, and a planar transition surface, according to one embodiment; wherein at least one of the cutting edges is chamfered.

[0031] FIG. 6 illustrates a PDC cutting element having a raised cutting surface including three cutting edges, a recess in a center of the raised cutting surface, and a concave transition surface, according to one embodiment.

[0032] FIG. 7 illustrates a PDC cutting element having a raised cutting surface comprising three cutting edges, a recess in the center of the raised cutting surface, and a concave transition surface, wherein at least one of the cutting edges is chamfered, according to one embodiment.

[0033] Figure 8 A PDC cutting element having a square shaped raised cutting surface comprising at least four cutting edges, a recess in the center of the raised cutting surface, a concave transition surface, and chamfered cutting edges, according to one embodiment, is shown.

[0034] Figure 9 A plot of axial load versus time acting on a prior art conventional cylindrical cutting element and a cutting element according to one embodiment having a raised cutting surface comprising three cutting edges and a recess in the center of the raised cutting surface is shown.

[0035] Figure 10 A plot of tangential load (or torque) versus time acting on a prior art conventional cylindrical cutting element and a cutting element according to one embodiment having a raised cutting surface comprising three cutting edges and a recess in the center of the raised cutting surface is shown.

[0036] FIG. 11 illustrates a wear state comparison of the following cutting elements: a prior art conventional cylindrical cutting element; a prior art cutting element having a flat tapered surface; a cutting element according to one embodiment having a raised cutting surface comprising three cutting edges, a recess in the center of the raised cutting surface, and a flat surface; and a cutting element according to one embodiment having a raised cutting surface comprising three cutting edges, a recess in the center of the raised cutting surface, and a concave surface. DETAILED DESCRIPTION

[0037] The illustrations presented herein are not actual views of any particular cutting assembly, tool, or drill string, but are idealized representations that are employed to describe the exemplary embodiments of the present disclosure. The following description provides specific details for a thorough understanding of the embodiments of the present disclosure in order to provide a complete description for the same. However, one having ordinary skill in the art will understand that the embodiments of the present disclosure can be practiced without employing many of the specific details described below. In fact, the embodiments of the present disclosure can be practiced in conjunction with a variety of conventional techniques. Additionally, the description provided below does not include all elements that form complete structures or assemblies. Only those process actions and structures necessary to understand the embodiments of the present disclosure are described below in detail. Additional conventional actions and structures can be employed. The drawings attached hereto are for exemplary purposes only and are not drawn to scale. Additionally, elements common between drawings can have corresponding number designations.

[0038] As used herein, the terms "have," "including," "include," "contain," "containing," "characterized by," and grammatical equivalents thereof are inclusive or open-ended terms that do not exclude additional unrecited elements or method steps, but rather are inclusive of the more restrictive terms "consist of and "consist essentially of and grammatical equivalents thereof.

[0039] As used herein, the term "may" with respect to a material, structure, feature, or method action indicates that such is contemplated as being useful in implementing an embodiment of the present disclosure, and this term is used in preference to the more restrictive term "is" in order to avoid any implication of a limitation of other compatibly usable alternatives.

[0040] As used herein, the term "configured" refers to the size, shape, material composition, and arrangement of one or more of the structure and the device that facilitate operation of one or more of the structure and the device in a predetermined manner.

[0041] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0042] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0043] As used herein, relational terms such as "first," "second," "top," "bottom," and the like can be used solely to distinguish one entity or action from another, without necessarily preferring one entity or action over the other, unless context clearly indicates otherwise.

[0044] As used herein, the term "substantially" with respect to a given parameter, characteristic, or condition means and includes to a degree that one of ordinary skill in the art would understand that the given parameter, characteristic, or condition is met, within acceptable tolerances, variances, or imperfections. By way of example, depending on the particular parameter, characteristic, or condition that is substantially met, the parameter, characteristic, or condition can be at least 90.0% met, at least 95.0% met, at least 99.0% met, or even at least 99.9% met.

[0045] As used herein, the term "about" used with respect to a given parameter includes the stated value and has the meaning conventionally associated with it in the art (e.g., it includes the degree of error associated with measurement of the given parameter).

[0046] As used herein, the term "earth-boring tool" means and includes any type of drill bit or tool used for drilling during the formation or enlargement of a borehole, and includes, for example, rotary drill bits, percussion drill bits, coring drill bits, eccentric drill bits, bicenter drill bits, reamers, mills, drag bits, roller cone drill bits, hybrid drill bits, and other drill bits and tools known in the art.

[0047] According to embodiments of the present disclosure, improvements in the thermal characteristics of the cutting elements can be achieved, as well as further improvements in cutting element efficiency and durability. Downhole earth-boring tools including cutting elements having novel geometries for improving thermal and mechanical efficiency will be described in further detail below.

[0048] Figure 3A 、 Figure 3B and Figure 3C Perspective, front, and side views of an embodiment of a PDC cutting element 300 according to the present disclosure are shown. The PDC cutting element 300 includes a raised cutting surface 302 having a cutting edge 308, a recess 304, and a transition surface 306. As shown in FIGS. 3A-3C, the raised cutting surface 302 is rectangular in shape and has two cutting edges 308 proximate to a side surface 316 of the cutting element 300. The optimal orientation of the PDC cutting element 300 is to have the cutting edges 308 oriented toward the formation material at the rectangular ends of the raised cutting surface 302. When significant wear has worn one side of the PDC cutting element 300, the PDC cutting element 300 can be rotated by removing the drill bit and by removing, rotating, and reattaching the PDC cutting element 300 to the drill bit so as to have the other cutting edge 308 oriented toward the formation material to be drilled. Figure 3A 、 Figure 3B and Figure 3C As shown in FIGS. 3A-3C, the raised cutting surface 302 is rectangular in shape and has two cutting edges 308 proximate to a side surface 316 of the cutting element 300. The optimal orientation of the PDC cutting element 300 is to have the cutting edges 308 oriented toward the formation material at the rectangular ends of the raised cutting surface 302. When significant wear has worn one side of the PDC cutting element 300, the PDC cutting element 300 can be rotated by removing the drill bit and by removing, rotating, and reattaching the PDC cutting element 300 to the drill bit so as to have the other cutting edge 308 oriented toward the formation material to be drilled.

[0049] Figure 3A 、 Figure 3B and Figure 3CA chamfered edge 318 along the raised cutting surface 302 and between the side surface 316 of the PDC cutting element 300 and the transition surface 306 is also shown. In some embodiments, the transition surface 306 extends from the raised cutting surface 302 to the side surface 316 of the PDC cutting element 300. In some embodiments, the transition surface 306 can be planar and can be parallel to the top surface 320 of the raised cutting surface 302 of the PDC cutting element 300. In some embodiments, the transition surface 306 can be concave or convex. In some embodiments, the transition surface 306 can define a more complex shape. Similarly, in some embodiments, the recess 304 can be square, circular, concave, convex, or can also define a more complex shape. In some embodiments, at least a portion of the recess 304 can be planar and can be in the same plane as the transition surface 306. The recess 304 can be formed to a depth that is deeper, the same, or not as deep as the transition surface 306. The raised cutting surface 302 can comprise between about 5% to 95% of the total surface area of the PDC cutting element 300. The polycrystalline diamond material 310 is bonded to the substrate 312 at the interface 314.

[0050] Figure 4A 、 Figure 4B and Figure 4C A perspective view, an elevation view, and a side view of an embodiment of a PDC cutting element 400 according to the present disclosure is shown. In this embodiment, the PDC cutting element 400 is configured to form a raised cutting surface 408 having three cutting edges 418, a recess 406 in the center of the raised cutting surface 408, and a planar transition surface 410. The planar transition surface 410 extends from the raised cutting surface 408 to a longitudinal side surface 412 of the PDC cutting element. The polycrystalline diamond material 402 is bonded to the substrate 404 at the interface 414. In some embodiments, the raised cutting surface 408 can be perpendicular to a longitudinal axis 420 of the cutting element 400 and can be generally parallel to the interface 414 between the polycrystalline diamond material 402 and the substrate 404. Formation material will be cut by the cutting edges 418 of the raised cutting surface 408. Formation material can also be cut by the planar transition surface 410 and the edge where the planar transition surface 410 intersects the longitudinal side surface 412 of the cutting element.

[0051] Tests show that the optimal orientation of the PDC cutting element 400 is to orient (or point) the vertices (or points) of the triangular shape toward the formation. The planar transition surface 410 can be configured to improve the flow of formation cuttings and drilling fluid around the face of the cutting element 400. When significant wear causes one side of the PDC cutting element 400 to wear, the PDC cutting element 400 can be rotated by removing the drill bit and by removing, rotating, and reattaching the PDC cutting element 400 to the drill bit, so that the second (and then the third) vertices are oriented toward the formation material to be drilled.

[0052] like Figure 4B As shown, the raised cutting surface 408 may extend to the longitudinal side surface 412 of the PDC cutting element 400, or it may not extend all the way to the longitudinal side surface 412 of the PDC cutting element 400. In some embodiments, the total thickness of the polycrystalline diamond material 402 may be between 1 mm and 10 mm, more preferably between 2 mm and 5 mm, and even more preferably about 3 mm to 3.5 mm.

[0053] The planar transition surface 410 and the groove 406 can be formed by grinding, milling, or laser machining of the polycrystalline diamond material, or by any other suitable method known in the art. The top surface 416 of the raised cut surface 408 can be planar and can be parallel to the interface 414 between the substrate 404 and the polycrystalline diamond material 402.

[0054] The planar transition surface 410 adjacent to the planar top surface 416 of the raised cut surface 408 can be formed at an angle between 1 degree and 90 degrees relative to the planar top surface 416 of the raised cut surface 408. In this embodiment, the cut edge 418 of the raised cut surface 408 is not chamfered, but as shown in Figures 3, 5, 7 and... Figure 8 As shown, the edges of the raised cutting surface 408 and the edges between the longitudinal side surface 412 of the PDC cutting element 400 and the planar transition surface 410 can be chamfered. In this embodiment, the transition surface 410 between the cutting edge 418 of the raised cutting surface 408 and the longitudinal side surface 412 of the PDC cutting element 400 is planar. However, the transition surface 410 can be concave (as shown in Figures 6 and 7), convex, or the transition surface 410 can define different and / or more complex shapes.

[0055] The top surface 416 of the raised cutting surface 408 can occupy approximately 5% to 95% of the total surface area of ​​the PDC cutting element 400. The cutting edge 418 of the raised cutting surface 408 can be straight, as shown in Figure 3. Figure 8As shown, or they can form part of an arc. In some embodiments, the edges of the raised cutting surface 408 can define more complex non-linear shapes. The grinding, machining, milling, or other process used to remove material from the polycrystalline diamond material 402 can extend up to 95% of the thickness of the polycrystalline diamond material 402 to form the grooves 406 and the planar transition surface 410 (and thus also the raised cutting surface 408).

[0056] The grooves 406 within the raised cutting surface 408 can conform to the shape of the outer edge of the raised cutting surface 408. However, the grooves 406 within the raised cutting surface 408 can define different shapes and can be in the form of a circle, square, rectangle, or other shape. The grooves 406 can be deeper, the same depth, or less deep than the depth of the machining outside of the grooves 406. The edges of the grooves 406 can form a 90 degree angle relative to the top surface 416 of the PDC cutting element 400, or they can be at any angle between 1 degree and 90 degrees. At least a portion of the grooves 406 (e.g., the bottom) can be planar and can also be parallel to the top surface 416 of the raised cutting surface 408 and / or parallel to the interface 414 between the substrate 404 and the polycrystalline diamond material 402. In some embodiments, the bottom of the grooves 406 can define a non-planar surface.

[0057] The grooves 406 of the PDC cutting element 400 can improve cutting performance in at least two ways: First, the grooves 406 can help to break up the formation material after it is cut away. As described above, the PDC cutting element 400 shears the formation material in a cutting action similar to a lathe. Thus, the cuttings from the formation material can be in the form of long ribbons, which can make the cuttings more difficult to handle and can cause bit balling and flow problems. Testing has shown that the grooves 406 help to break the formation material into smaller pieces rather than long ribbons, thereby improving the cutting efficiency of the PDC cutting element 400. The improved cutting action has better flow around the PDC cutting element 400, which will improve the efficiency of the bit and can allow for the use of smaller forces (axial and tangential) to operate the bit to maintain a specified rate of penetration (ROP). This will result in less torque on the rotary drill bit and less weight on the bit.

[0058] Second, testing has shown that the grooves 406 help to keep the polycrystalline diamond material 402 of the PDC cutting element 400 cooler during operation. This can be because the grooves 406 increase the surface area, which improves the heat transfer from the top surface 416 of the PDC cutting element 400 to the drilling fluid. Testing has demonstrated that the cooling effect of the PDC cutting element 400 is improved by 25%, which allows for increased cutting with better performance characteristics and less degradation of the diamond-diamond bonds or thermal damage to the polycrystalline diamond material 402.

[0059] Figure 5A 、 Figure 5B and Figure 5C A perspective view, an elevation view, and a side view of an embodiment of a PDC cutting element 500 according to the present disclosure is shown. In this embodiment, the PDC cutting element 500 is configured to form a raised cutting surface 504 having three cutting edges 516, a recess 502 at the center of the raised cutting surface 504, and a planar transition surface 508. The planar transition surface 508 extends from the cutting edges 516 of the raised cutting surface 504 to a side surface 518 of the PDC cutting element 500. Polycrystalline diamond material 510 is bonded to a substrate 512 at an interface 514. Figure 5A 、 Figure 5B and Figure 5C A chamfered edge 506 along the raised cutting surface 504 and between the side surface 518 and the planar transition surface 508 of the PDC cutting element 500 is also shown. As described above, the chamfered edge 506 has been found to reduce the tendency of the polycrystalline diamond material 510 to spall and fracture.

[0060] Figure 6A 、 Figure 6B and Figure 6C A perspective view, an elevation view, and a side view of an embodiment of a PDC cutting element 600 according to the present disclosure is shown. In this embodiment, the PDC cutting element 600 is configured to form a raised cutting surface 606 having three cutting edges 610, a recess 602, and a concave transition surface 604. The concave transition surface 604 extends from the cutting edges 610 to a side surface 608 of the PDC cutting element 600. Polycrystalline diamond material 612 is bonded to a substrate 614 at an interface 616. Similar to the planar transition surfaces 410 and 508 shown in FIGS. 4 and 5, respectively, the concave transition surface 604 improves the flow of fluid around the PDC cutting element 600 and increases the efficiency and durability of the PDC cutting element 600.

[0061] Figure 7A 、 Figure 7B and Figure 7C A perspective view, an elevation view, and a side view of an embodiment of a PDC cutting element 700 according to the present disclosure is shown. In this embodiment, the PDC cutting element 700 is configured to form a raised cutting surface 708 having three cutting edges 714, a recess 702, and a concave transition surface 706. The concave transition surface 706 extends from the cutting edges 714 to a side surface 710 of the PDC cutting element 700. Polycrystalline diamond material 712 is bonded to a substrate 716 at an interface 718. Figure 7A 、 Figure 7B and Figure 7CA chamfered edge 704 is also shown along the edge of the raised cutting surface 708 and between the concave transition surface 706 and the side surface 710 of the PDC cutting element 700. As described above, the chamfered edge 704 has been found to reduce the tendency of the polycrystalline diamond material 712 to spall and fracture.

[0062] Figure 8 An embodiment of a PDC cutting element 800 according to the present disclosure is shown. In this embodiment, the PDC cutting element is configured to form a raised cutting surface 812 having four cutting edges 810, a recess 808, and a planar transition surface 806. In this embodiment, the raised cutting surface 812 forms a square shape. Similar to the triangular shaped raised cutting surfaces described above, it is expected that the highest rate of cut will be obtained when the cutting edges 810 at the square corners of the raised cutting surface 812 are oriented toward the formation material.

[0063] Figure 8 A chamfered edge 816 is also shown along the cutting edges 810 of the raised cutting surface 812 and between the side surface 814 and the planar transition surface 806 of the PDC cutting element 800. The polycrystalline diamond material 802 is bonded to the substrate 804 at an interface 818. The planar transition surface 806 extends from the raised cutting surface 812 to the side surface 814 of the PDC cutting element 800.

[0064] Figure 9 is a plot of the axial load on the cutting element as a function of time. The axial load is the force exerted on the cutting element that is required for the cutting element to cut into the formation material. This can also be referred to as the weight on bit (WOB) because in operation, the cutting element will be attached to a rotating drill bit and the axial load is a measure of the amount of axial force (weight on bit) that is required to allow the drill bit to engage the formation material.

[0065] Figure 9 The curves in each of the plots represent a single cutting element that was tested while interacting with the formation material. The axial load is plotted on the Y axis in kilograms while the X axis represents time and each point represents a measurement (or series of measurements) at a particular time. The prior art conventional cylindrical cutting elements are represented by the lighter gray dots. One embodiment of the present invention, the three-bladed cutting element with improved geometry, is represented by the darker black dots.

[0066] Figure 9 The rise of the two lines in over time indicates that each cutting element requires a greater axial load (or force) over time to maintain a given rate of penetration. As the cutting elements wear and dull over time, a greater force needs to be exerted on the cutting elements. As can be seen in Figure 9As shown, the prior art conventional cylindrical cutting elements always require about 200 kg - 250 kg more axial load than the improved geometry three-bladed cutting elements. The greater the force required to move the cutting elements means the greater the WOB. This also means greater wear on the cutting elements and shorter life of the cutting elements. In addition, the greater the force also means the greater the heat generated at the cutting elements, which, as noted above, can cause thermal damage to the cutting elements and the polycrystalline diamond material.

[0067] Figure 10 is a plot of tangential load on the cutting element as a function of time. Tangential load is the side force exerted on the cutting element as it engages the formation material. Tangential load represents the torque required to rotate the drill bit to maintain a given ROP in the formation material.

[0068] Similar to Figure 9 the plot of Figure 10 shows that the prior art conventional cylindrical cutting elements require about 90 kg to 140 kg more force (torque) than the improved geometry three-bladed cutting elements. As noted above, the higher the torque (force) required means the higher the operating temperature of the cutting elements and the drill bit, the greater the wear and the shorter the life.

[0069] Figure 11A shows a wear scar 1106 of a prior art conventional cylindrical cutting element 1102 having a cutting edge 1104. Figure 11B shows a wear scar 1114 of a prior art cutting element 1108 having a flat-tapered surface 1110 and a cutting edge 1112. Figure 11C shows a wear scar 1126 of a cutting element 1116 having a raised cutting surface 1118, a groove 1122, and a flat transition surface 1124. In this embodiment, the raised cutting surface 1118 has three cutting edges 1120. Figure 11D shows a wear scar 1138 of a cutting element 1128 having a raised cutting surface 1130, a groove 1134, and an arcuate transition surface 1136. In this embodiment, the raised cutting surface 1130 has three cutting edges 1132. As shown in the following chart, a close examination shows that the wear scar area of Figure 11B , Figure 11C and Figure 11D is less than the wear scar area of Figure 11A .

[0070]

[0071]

[0072] Comparison chart of wear states of four cutting elements.

[0073] The charts above compare the wear states of the four cutting elements described above. Wear state 0.5 indicates that one-sixteenth of the cutting element's edge is worn. Wear state 1 indicates that one-eighth of the cutting element's edge is worn, and 1.5 indicates that three-sixteenths of the cutting element's edge is worn. Figure 11A , Figure 11B , Figure 11C and Figure 11D A cutting element with a wear condition of "1" (or one-eighth) is shown. For example... Figure 11A As shown in the diagrams and figures, conventional cylindrical elements of the prior art have a larger "grind" area than any improved cut element. For two of the three measurement states, Figure 11D The three-bladed concave cutting element shown has the smallest wear area.

[0074] Figure 9 The curves in Figure 11 and the graphs above demonstrate that, compared to conventional cylindrical drill bits of the prior art, the raised cut surface, with its improved implementation, requires less torque, less wobble weight (WOB), and results in a smaller wear area. Therefore, the curves and graphs show that the improved raised cut surface lasts longer and is more durable than conventional cylindrical drill bits of the prior art.

[0075] The embodiments of this disclosure described above and illustrated in the accompanying drawings do not limit the scope of the invention, as these embodiments are merely examples of embodiments of the invention, the scope of which is defined by the appended claims and their legal equivalents. Any equivalent embodiments are intended to fall within the scope of this disclosure. In fact, various modifications of this disclosure beyond those shown and described herein (such as alternative useful combinations of the described elements) will become apparent to those skilled in the art based on the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims and their legal equivalents.

[0076] In exemplary embodiments, a typical rotary "drag" bit made of steel and using PDC cutting elements is described. However, those skilled in the art will appreciate that the size, shape, and / or configuration of the bit can vary depending on the operational design parameters without departing from the spirit of the present application. Moreover, the present application can operate on non-rotary bits, and the present application is applicable to any structure associated with drilling, including percussion, impact, or "hammer" bits. Those of ordinary skill in the art will further appreciate that one or more features of any of the illustrated embodiments can be combined with one or more features from another embodiment to form yet another combination within the scope of the present application as described and claimed herein. Thus, although certain representative embodiments and details have been shown for purposes of illustrating the present application, it will be apparent to those skilled in the art that various changes in the embodiments and details can be made therein without departing from the scope of the application as defined by the appended claims.

[0077] Additional non-limiting exemplary embodiments of the present disclosure are described below.

[0078] Embodiment 1 : A cutting element comprising a substrate and a polycrystalline diamond material attached to the substrate at an interface. The polycrystalline diamond material comprises a raised cutting surface having at least two cutting edges, a recess at a center of the raised cutting surface; and a transition surface between the at least two cutting edges of the raised cutting surface and a longitudinal side surface of the cutting element.

[0079] Embodiment 2: The cutting element of embodiment 1, wherein the raised cutting surface covers between 10% and 90% of a total surface area of a cutting face of the cutting element.

[0080] Embodiment 3: The cutting element of embodiment 1 or embodiment 2, wherein at least one edge of the raised cutting surface comprises a chamfered edge.

[0081] Embodiment 4: The cutting element of any one of embodiments 1 to 3, wherein at least a portion of the raised cutting surface extends to a longitudinal side surface of the cutting element.

[0082] Embodiment 5: The cutting element of any one of embodiments 1 to 4, wherein the transition surface has a concave surface profile.

[0083] Embodiment 6: The cutting element of any one of embodiments 1 to 5, wherein the cutting edges defining the raised cutting surface have a rectangular shape.

[0084] Embodiment 7: The cutting element of any one of embodiments 1 to 5, wherein the raised cutting surface comprises at least three cutting edges.

[0085] Embodiment 8: The cutting element of any one of embodiments 1-7, wherein the cutting edge defining the raised cutting surface has a triangular shape.

[0086] Embodiment 9: The cutting element of any one of embodiments 1-8, wherein an apex of the triangular shape is oriented toward the formation material.

[0087] Embodiment 10: The cutting element of any one of embodiments 1-9, wherein the raised cutting surface comprises at least four cutting edges.

[0088] Embodiment 11: A downhole earth boring tool comprising a bit body; a plurality of blades extending from one end of the body, each blade comprising a leading edge portion; and at least one cutting element disposed within each blade proximate the leading edge portion of the blade. The at least one cutting element comprises a substrate and a polycrystalline diamond material attached to the substrate at an interface. The polycrystalline diamond material comprises a raised cutting surface having at least three cutting edges, a recess at a center of the raised cutting surface, and a transition surface between the at least three cutting edges of the raised cutting surface and a longitudinal side surface of the cutting element.

[0089] Embodiment 12: The downhole earth boring tool of embodiment 11, wherein the transition surface is planar.

[0090] Embodiment 13: The downhole earth boring tool of embodiment 11 or embodiment 12, wherein the planar transition surface is perpendicular to a longitudinal axis of the cutting element.

[0091] Embodiment 14: The downhole earth boring tool of any one of embodiments 11-13, wherein the raised cutting surface is parallel to the planar transition surface.

[0092] Embodiment 15: The downhole earth boring tool of any one of embodiments 11-14, wherein the raised cutting surface and the planar transition surface are parallel to an interface between the substrate and the polycrystalline diamond material.

[0093] Embodiment 16: The downhole earth boring tool of any one of embodiments 11-15, wherein at least a portion of a surface of the recess is parallel to the raised cutting surface and the transition surface.

[0094] Embodiment 17: The downhole earth boring tool of any one of embodiments 11-16, wherein the transition surface and the at least a portion of the recess that are parallel to each other are at the same height.

[0095] Embodiment 18: A method of manufacturing a downhole earth-boring tool, the method comprising: forming a bit body; forming at least one blade extending from one end of the bit body, the at least one blade comprising a leading edge portion, and forming at least one cutting element in each at least one blade proximate the leading edge portion of the at least one blade. Wherein forming the at least one cutting element comprises forming a polycrystalline diamond material, affixing a first end of the polycrystalline diamond material to a substrate at an interface, and shaping a second end of the polycrystalline diamond material. Wherein shaping the second end of the polycrystalline diamond material comprises forming at least two cutting edges defining a raised cutting surface, forming at least one recess in a center of the raised cutting surface, and forming at least one transition surface between at least one of the at least two cutting edges defining the raised cutting surface and a longitudinal side surface of the cutting element.

[0096] Embodiment 19: The method of embodiment 18, further comprising forming at least a portion of the raised cutting surface, the recess, and the transition surface by laser machining.

[0097] Embodiment 20: The method of embodiment 18 or embodiment 19, further comprising forming at least a portion of the raised cutting surface, the recess, and the transition surface by grinding.

[0098] The embodiments of the disclosure described above and illustrated in the drawings are not intended to limit the scope of the present application, as these embodiments are merely examples of embodiments of the present application and many variations are possible using the concepts taught from this disclosure and the associated drawings. Any equivalent embodiments are intended to fall within the scope of the present disclosure. Indeed, various modifications of the foregoing, in addition to those described, can become apparent to those skilled in the art from the description and the accompanying drawings. Such modifications are intended to fall within the scope of the appended claims and their legal equivalents.

Claims

1. A cutting element comprising: a substrate; and a polycrystalline diamond material attached to the substrate at an interface, the polycrystalline diamond material comprising: a raised cutting surface comprising at least two cutting edges; a recess in the center of the raised cutting surface, wherein the recess is surrounded by the cutting edges; and a transition surface between the at least two cutting edges of the raised cutting surface and a longitudinal side surface of the cutting element; wherein the cutting edge between the transition surface and the longitudinal side surface is a chamfered edge.

2. The cutting element of claim 1, wherein the raised cutting surface covers between 10% and 90% of the total surface area of the cutting face of the cutting element.

3. The cutting element of claim 1, wherein at least one edge of the raised cutting surface comprises a chamfered edge.

4. The cutting element of claim 1, wherein at least a portion of the raised cutting surface extends to the longitudinal side surface of the cutting element.

5. The cutting element of claim 1, wherein the transition surface has a concave surface profile.

6. The cutting element of claim 1, wherein the cutting edges defining the raised cutting surface have a rectangular shape.

7. The cutting element of claim 1, wherein the raised cutting surface comprises at least three cutting edges.

8. The cutting element of claim 7, wherein the cutting edges defining the raised cutting surface have a triangular shape.

9. The cutting element of claim 8, wherein the apex of the triangular shape is oriented toward the formation material.

10. The cutting element of claim 7, wherein the raised cutting surface comprises at least four cutting edges.

11. An earth-boring downhole tool comprising: a bit body; a plurality of blades extending from one end of the bit body, each blade comprising a leading edge portion; and at least one cutting element disposed within each blade proximate the leading edge portion of the blade, the at least one cutting element comprising: a substrate; and a polycrystalline diamond material attached to the substrate at an interface, the polycrystalline diamond material comprising: a raised cutting surface comprising at least three cutting edges; a recess in the center of the raised cutting surface, wherein the recess is surrounded by the cutting edges; and a transition surface between the at least three cutting edges of the raised cutting surface and a longitudinal side surface of the cutting element; wherein the cutting edge between the transition surface and the longitudinal side surface is a chamfered edge.

12. The earth-boring downhole tool of claim 11, wherein the transition surface is planar.

13. The earth-boring downhole tool of claim 12, wherein the planar transition surface is perpendicular to a longitudinal axis of the cutting element.

14. The earth-boring downhole tool of claim 13, wherein the raised cutting surface is parallel to the planar transition surface.

15. The earth-boring downhole tool of claim 14, wherein the raised cutting surface and the planar transition surface are parallel to an interface between the substrate and the polycrystalline diamond material.

16. The earth-boring downhole tool of claim 15, wherein at least a portion of a surface of the recess is parallel to the raised cutting surface and the transition surface.

17. The earth-boring downhole tool of claim 16, wherein the transition surface and the at least a portion of the recess that are parallel to each other are at a same height.

18. A method of manufacturing an earth-boring downhole tool, the method comprising: forming a bit body; forming at least one blade extending from one end of the bit body, the at least one blade including a leading edge portion; and forming at least one cutting element in each at least one blade proximate the leading edge portion of the at least one blade; wherein forming the at least one cutting element comprises: forming a polycrystalline diamond material; attaching a first end of the polycrystalline diamond material to a substrate at an interface; and shaping a second end of the polycrystalline diamond material; wherein shaping the second end of the polycrystalline diamond material comprises: forming at least two cutting edges defining a raised cutting surface; forming at least one recess in a center of the raised cutting surface such that the recess is surrounded by the cutting edges; forming at least one transition surface between at least one of the at least two cutting edges defining the raised cutting surface and a longitudinal side surface of the cutting element; and chamfering a cutting edge between the transition surface and the longitudinal side surface into a chamfered edge.

19. The method of claim 18, further comprising forming at least a portion of the raised cutting surface, the recess, and the transition surface by laser machining.

20. The method of claim 18, further comprising forming at least a portion of the raised cutting surface, the recess, and the transition surface by grinding.

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