Drill bits and other downhole drilling tools with non-cylindrical cutter pockets

Abstract

Embodiments of the invention may include a downhole tool that may include a body including a face and an axis of rotation. The tool may include a plurality of blades disposed on a face of the body. Each blade of the plurality of blades may define a plurality of cutter pockets. At least one cutter pocket of the plurality of cutter pockets may include a non-circular cross-section. The tool may include a plurality of cutters. A portion of each cutter may be disposed within a respective cutter pocket of the plurality of cutter pockets. The portion of each cutter may have a cross-sectional shape that matches the cross-sectional shape of the corresponding cutter pocket.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit and priority of U.S. Patent Application No. 63 / 504,930, filed May 30, 2023, entitled “DRILL BITS WITH NON-CYLINDRICAL CUTTER POCKETS”, the entire contents of which are incorporated herein by reference.

[0003] This application claims the benefit and priority of U.S. Patent Application No. 63 / 510,562, filed June 27, 2023, entitled “SHAPED CUTTER NON-PLANARINTERFACES”, the entire contents of which are incorporated herein by reference.

[0004] This application claims the benefit and priority of U.S. Patent Application No. 63 / 518,744, filed August 10, 2023, entitled “DRILL BITS WITH NON-CYLINDRICAL CUTTER POCKETS”, the entire contents of which are incorporated herein by reference.

[0005] This application claims the benefit and priority of U.S. Patent Application No. 63 / 578,462, filed August 24, 2023, entitled “DRILL BITS WITH NON-CYLINDRICAL CUTTER POCKETS”, the entire contents of which are incorporated herein by reference. Technical Field

[0006] This disclosure generally relates to drill bits having inserts with improved cutting elements. In particular, this disclosure relates to drill bits and other downhole drilling tools having cutting element recesses and cutting elements with non-circular cross-sections, such that the cutting element recesses can self-align with the cutting elements inserted therein. Background Technology

[0007] Downhole drilling tools, drill bits (such as rotary scraper bits), reamers, and similar downhole tools are well known for drilling or forming holes in underground rock formations. When drilling oil and gas wells, geothermal wells, mining boreholes, and other underground boreholes, rotary scraper bits utilize discrete cutting elements called "cutting elements," which are mounted in fixed positions on the tool body against the formation. As the tool body rotates, the cutting elements scrape the formation, breaking it apart through shearing action. This shearing action creates fine chips, which are expelled hydraulically or pneumatically by drilling fluid pumped through nozzles in the tool body. Conventional cutting elements are formed from cylinders. However, such cylinders can present limitations in downhole tool design. For example, in cases where the cutting element includes discrete cutting tips, it can be difficult to align the cutting tips in the desired orientation due to the need for manual brazing to secure the cutting element to the downhole tool. Additionally, the size and shape of the cylinder can limit the number of cutting elements on the cutting edge and restrict the customizability of the drill bit's cutting profile. Therefore, there is a need to improve cutting elements and downhole tools that include such cutting elements. Summary of the Invention

[0008] Embodiments of the present invention may include a downhole tool, which may include a body comprising a face and an axis of rotation. The tool may include a plurality of blades disposed on the face of the body. Each of the plurality of blades may define a plurality of cutting recesses. At least one of the plurality of cutting recesses may include a non-circular cross-section. The tool may include a plurality of cutting elements. A portion of each cutting element may be disposed within a corresponding cutting recess among the plurality of cutting recesses. The portion of each cutting element may have a cross-sectional shape matching the cross-sectional shape of the corresponding recess.

[0009] In some embodiments, the downhole tool may be a drill bit. The downhole tool may include a reamer. The at least one recess may have a generally rectangular cross-section. The generally rectangular cross-section may include two orthogonal straight sides and a rounded corner connecting the two orthogonal straight sides. Measured from the central axis of the cutting recess, the width of each rounded corner may be between 5 degrees and 45 degrees. The cutting tool may include a plurality of knuckles. Each of the plurality of knuckles may protrude from the top surface of one of the plurality of cutting tools and may be aligned with a corresponding cutting recess in the plurality of cutting recesses, and may support a portion of the base of one of the plurality of cutting tools seated within the corresponding cutting recess in the plurality of cutting recesses. The shape and size of each of the plurality of knuckles may substantially correspond to the size and shape of a portion of one of the plurality of cutting tools extending above the top surface of the corresponding cutting tool in the plurality of cutting tools on which one of the plurality of cutting tools is mounted. The top surface of each of the plurality of knuckles may taper downward toward the top surface of the corresponding cutting tool in the plurality of cutting tools in a direction away from one of the plurality of cutting tools. Each of the plurality of finger segments can be axially aligned with a corresponding cutting element among the plurality of cutting elements. The body may include a plurality of channels. Each channel may be formed between adjacent cutting elements among the plurality of cutting elements. The body may include a plurality of nozzles. Each nozzle may be disposed within one of the plurality of channels. The outlet of each nozzle may be aligned with one of the plurality of cutting elements facing the corresponding channel. At least one of the plurality of cutting elements may include a diamond table having a non-cylindrical outer periphery, the diamond table being configured to rotate within a corresponding cutting element recess about the central axis of the at least one of the plurality of cutting elements at an angle between 60 degrees and 300 degrees to expose a new cutting edge with a point load capacity greater than that of a conventional cylindrical cutting element of similar size, while maintaining a brazing gap thickness of 0.015 inches or less over more than 85% of the brazable surface area of ​​a conventional cylindrical cutting element of similar size. The shape and orientation of both the at least one cutting recess and the corresponding cutting element disposed in the at least one cutting recess can be selected such that when the corresponding cutting element is inserted into the at least one cutting recess, the corresponding cutting element is oriented such that the cutting tip of the corresponding cutting element protrudes beyond the top surface of the corresponding cutting element among the plurality of cutting elements.

[0010] Some embodiments of this technology may include a cutting element for downhole tools. The cutting element may include a substrate comprising a brazed surface. At least a portion of the brazed surface may include a first non-circular cross-section. The cutting element may include a diamond station. The diamond station may include a bottom surface connected to the substrate. The diamond station may include a cutting face opposite the bottom surface. The cutting face may include a second non-circular cross-section.

[0011] In some embodiments, one or both of the first non-circular cross section and the second non-circular cross section may include one or more concave and / or convex regions. The cutting surface may be non-planar. The cutting surface may include multiple discrete cutting tips. One or both of the first non-circular cross section and the second non-circular cross section may include a generally quadrilateral shape. The cutting element may be symmetrical about two vertical planes extending through both the matrix and the diamond stage. One or both of the first non-circular cross section and the second non-circular cross section may include two or more straight edges connected via multiple curved corners. The ratio of the length of the straight edge to the length of the curved corner may be at least 0.5:1. One or both of the first non-circular cross section and the second non-circular cross section may include a generally rectangular shape. The generally rectangular shape may include four straight edges and four rounded corners. One or both of the first non-circular cross section and the second non-circular cross section may include a generally triangular shape. The generally triangular shape may include three straight edges and three rounded corners. One or both of the first non-circular cross section and the second non-circular cross section may include a stadium shape. The diamond stage may include chamfered edges extending from the cutting surface to the lateral sides of the diamond stage. The angle of the chamfer edge relative to the cutting surface can vary along the periphery of the cutting surface. The angle of the chamfer edge relative to the cutting surface in the cutting region of the cutting surface can be greater than the angle of the chamfer edge relative to the cutting surface in the middle region of the cutting surface. The angle of the chamfer edge relative to the cutting surface in the cutting region of the cutting surface can be less than the angle of the chamfer edge relative to the cutting surface in the middle region of the cutting surface. The depth of the chamfer edge can vary along the periphery of the cutting surface. The depth of the chamfer edge in the cutting region of the cutting surface can be greater than the depth of the chamfer edge in the middle region of the cutting surface. The depth of the chamfer edge in the cutting region of the cutting surface can be less than the depth of the chamfer edge in the middle region of the cutting surface. The matrix can include a non-planar interface projecting from the matrix along the direction of the diamond stage. This non-planar interface can include a non-circular cross-section. The shape of the outer periphery of the non-planar interface can match the shape of the outer periphery of the topmost planar surface of the matrix. The thickness of the non-planar interface can vary over the surface region of the non-planar interface. The thickness of the diamond stage can vary over the surface region of the diamond stage. Variations in the thickness of the non-planar interface can correspond to variations in the thickness of the diamond stage over the surface region of the diamond stage. The diamond abutment may include a protruding feature. In the region corresponding to the protruding feature, the thickness of the non-planar interface may be increased. The diamond abutment may include a recessed feature. In the region corresponding to the recessed feature, the thickness of the non-planar interface may be decreased. The distance from the peripheral edge of the non-planar interface to the peripheral edge of the diamond abutment may be kept consistent in such a way that the deviation from the maximum distance from the peripheral edge of the non-planar interface to the peripheral edge of the diamond abutment over the entire periphery of the diamond abutment is within 20%. The first non-circular cross-section and the second non-circular cross-section may have the same shape.

[0012] Some embodiments of this technology may include a cutting element for a downhole tool, the cutting element including a diamond station having a non-cylindrical outer perimeter, the diamond station being configured to rotate within a recess of the cutting element of the downhole tool about the central axis of the diamond station at an angle between 60 and 300 degrees to expose a new cutting edge with a point load capacity greater than that of a conventional cylindrical cutting element of similar size, while maintaining a brazing gap thickness of 0.015 inches or less over more than 85% of the brazable surface area of ​​a conventional cylindrical cutting element of similar size.

[0013] Some embodiments of this technology may include a cutting element for a downhole tool, the cutting element comprising a body having a central axis. The radial distance between the outer surface of the cutting element and the central axis may vary around the outer periphery of the body along at least 50% of the outer circumference of the cutting element and along at least 50% of the length of the body.

[0014] Some embodiments of this technology may include a method of attaching a cutting element to a downhole tool. The method may include inserting a cutting element having a non-circular cross-section into a non-cylindrical recess formed in the downhole tool, such that a gap is formed between the outer surface of the cutting element and the wall of the recess. The method may include providing a metallic material into the gap. The method may include setting the cutting element in the recess such that the cutting element is connected to the downhole tool.

[0015] In some embodiments, the metallic material may include a brazing alloy. Both the recess and the cutting element may have a generally rectangular cross-section. Both the recess and the cutting element may have a generally triangular cross-section. Both the recess and the cutting element may have a generally stadium-shaped cross-section. Both the recess and the cutting element may have a generally pentagonal cross-section. Both the recess and the cutting element may have a generally hexagonal cross-section. The recess may be formed within a cutting edge extending outward from the face of the downhole tool. The shape and orientation of both the cutting element and the recess can be selected such that when the cutting element is inserted into the recess, it is oriented such that the cutting tip of the cutting element protrudes beyond the top surface of the cutting edge.

[0016] Some embodiments of this technology may include a method of manufacturing a downhole tool. The method may include a mold forming the body of the downhole tool. The method may include inserting a plurality of cutting element recess displacements within the mold. The plurality of cutting element recess displacements may have a non-circular cross-section. The plurality of cutting element recess displacements may be aligned within the mold such that the displacements define the size and orientation of the cutting element recesses. The method may include filling the mold with a carbide matrix material and a binder material. The method may include heating the filled mold to form the body of the downhole tool. The plurality of cutting element recess displacements may form cutting element recesses within the body of the downhole tool. At least one of the cutting element recesses may include a non-circular cross-section configured to automatically orient the cutting element in a cutting position. The method may include removing the body of the downhole tool from the mold. The method may include inserting a cutting element into at least one of the cutting element recesses. At least one of the cutting elements may have a non-circular cross-section that substantially matches the non-circular cross-section of a corresponding cutting element recess in the cutting element recess.

[0017] In some embodiments, inserting a plurality of cutting element recess replacements into a mold may include inserting each cutting element recess replacement into a groove formed in the mold. Each of the plurality of cutting element recess replacements may be manually aligned within a corresponding cutting element recess in the cutting element recess. Each of the plurality of cutting element recess replacements may be aligned within a corresponding cutting element recess in the cutting element recess by using an indexing feature formed in one or both of the mold and the corresponding cutting element recess replacement. One of the grooves and the corresponding cutting element recess replacements may include a ridge, and the other of the grooves and the corresponding cutting element recess replacements may define a recess. Inserting a ridge into a recess may align the corresponding cutting element recess replacement within the groove. One of the grooves and the corresponding cutting element recess replacements may include a convex surface, and the other of the grooves and the corresponding cutting element recess replacements may define a concave surface. Approaching the concave surface against the convex surface may align the corresponding cutting element recess replacement within the groove. Each of the grooves and the corresponding cutting element recess replacements may define a slot. A key can be inserted into two slots to align the corresponding cutting insert recess replacement within the groove. The method may include removing the cutting insert recess replacement from the body of the downhole tool before inserting the cutting insert. The method may include brazing each cutting insert into the corresponding cutting insert recess. The body of the downhole tool may include a plurality of blades extending away from the body of the downhole tool. The shape and orientation of each cutting insert recess and the corresponding cutting insert disposed within the cutting insert recess can be selected such that when the corresponding cutting insert is inserted into the cutting insert recess, the corresponding cutting insert is oriented such that the cutting tip of the corresponding cutting insert protrudes beyond the top surface of the corresponding blade among the plurality of blades.

[0018] Some embodiments of this technology may include a method of manufacturing a downhole tool, the method including forming a body of the downhole tool. The body may include a plurality of blades. Each blade may include a plurality of cutting recesses. At least one of the plurality of cutting recesses may include a non-circular cross-section. The method may include hardfacing the body of the downhole tool. The method may include inserting a cutting element into each of the plurality of cutting recesses. At least one cutting element may include a non-circular cross-section that substantially matches the non-circular cross-section of a corresponding cutting recess of at least one of the plurality of cutting recesses. The method may include brazing each cutting element into a corresponding cutting recess of the cutting recess.

[0019] In some embodiments, forming the body of a downhole tool may include machining the body from a steel billet. Surface hardening may include fusing a carbide material and a binder to at least a portion of the body of the downhole tool. The shape and orientation of both each cutting recess and the corresponding cutting element disposed within the cutting recess may be selected such that when the corresponding cutting element is inserted into the cutting recess, the corresponding cutting element is oriented such that the cutting tip of the corresponding cutting element protrudes beyond the top surface of the corresponding cutting element among the plurality of cutting elements. Forming the body of the downhole tool may include machining each of the plurality of cutting recesses in the body of the downhole tool. Forming the body of the downhole tool may include forming each of the plurality of cutting recesses to have a circular cross-section. Forming the body of the downhole tool may include welding a gasket to the circular cross-section to form a non-circular cross-section.

[0020] Some embodiments of this technology may include a method for reorienting a cutting element to a downhole tool. The method may include determining that a first cutting tip of the cutting element on the cutting tool's insert is excessively worn. The first cutting tip may be in a cutting position, in which the first cutting tip protrudes above the top surface of the insert. The cutting element may include a plurality of discrete cutting tips. The cutting element may include a non-circular cross-section corresponding to the cross-section of a cutting element recess in which the cutting element is fixed. The method may include determining that a second cutting tip among the plurality of discrete cutting tips is in a state sufficient for use in the cutting position. The method may include removing the cutting element from the cutting element recess. The method may include rotating the cutting element and inserting it into the cutting element recess, wherein the second cutting tip is oriented into the cutting position. The method may include securing the cutting element within the cutting element recess. In some embodiments, securing the cutting element within the cutting element recess may include brazing the cutting element to the cutting element recess. The shape and orientation of the cutting element recess and the cutting element may be selected such that when the cutting element is inserted into the cutting element recess, the cutting element is oriented such that one of the plurality of discrete cutting tips is in the cutting position. The determination that the first cutting tip is excessively worn can be made by classifying the first cutting tip of the cutting element on the downhole tool insert based on one or more predetermined criteria. The determination that the second cutting tip is in a usable condition in the cutting position can be made by classifying the second cutting tip among multiple discrete cutting tips based on one or more criteria.

[0021] Some embodiments of this technology may include a drill bit, which may include a body having a face for engaging the bottom of a wellbore. The body may include a rotation axis extending along its length. The drill bit may include a plurality of blades formed on the body. The drill bit may include a plurality of cutting elements on each of the plurality of blades. The plurality of cutting elements may include multiple pairs of cutting elements. Each pair of cutting elements may include a first cutting element and a second cutting element, both being radially distanced from the rotation axis. One or both of the first and second cutting elements in each pair of cutting elements may include a plurality of discrete cutting tips. Each cutting element may be mounted on a corresponding blade, wherein a single cutting tip extends beyond the top surface of the corresponding blade.

[0022] In some embodiments, at least some of the plurality of cutting elements may be located on the same cutting tool. At least some of the plurality of cutting elements may be located on different cutting tools. One of the first and second cutting elements in each pair may be a cylindrical cutting element. The first and second cutting elements in each pair may include the same cutting tip. The first and second cutting elements in each pair may include different cutting tips. The first and second cutting elements in each pair may include different cross-sectional shapes.

[0023] Some embodiments of this technology may include a drill bit for advancing a borehole. The drill bit may include a body having a face that engages with the bottom of the wellbore. The body may include a rotation axis extending along its length. The drill bit may include a plurality of blades formed on the body. The drill bit may include a plurality of cutting elements mounted on each of the plurality of blades. At least one of the blades may be a biasing blade having: an inner region supporting an inner group of cutting elements along a first leading edge portion of the biasing blade; and an outer region supporting an outer group of cutting elements along a second leading edge portion of the biasing blade. The second leading edge portion may be rotatably biased from the first leading edge portion. At least some of the plurality of cutting elements may include a plurality of discrete cutting tips. Each cutting element may be mounted on a corresponding blade, wherein a single cutting tip of the plurality of discrete cutting tips extends beyond the top surface of the corresponding blade.

[0024] In some embodiments, the at least some cutting elements may include inner group cutting elements. The at least some cutting elements may include outer group cutting elements. The at least some cutting elements may include both inner group cutting elements and outer group cutting elements. Attached Figure Description

[0025] A further understanding of the nature and advantages of the various embodiments can be achieved by referring to the following accompanying drawings. In the drawings, similar parts or features may have the same reference numerals. Furthermore, different parts of the same type can be distinguished by adding a set of parentheses after the reference numerals, containing a second reference numeral to differentiate similar parts. If only the first reference numeral is used in the specification, the description applies to any of the similar parts having the same first reference numeral, regardless of the second reference numeral.

[0026] Figure 1 This is an isometric view of a drill bit according to an embodiment of the present invention.

[0027] Figure 2 This is an isometric view of a drill bit according to an embodiment of the present invention.

[0028] Figure 3 This is an isometric view of a hole expander according to an embodiment of the present invention.

[0029] Figures 4A-4D Different views of a generally rectangular cut part according to an embodiment of the present invention are shown.

[0030] Figures 5A-5D Different views of a generally triangular cutting part according to an embodiment of the present invention are shown.

[0031] Figures 6A-6D Different views of a generally pentagonal cut part according to an embodiment of the present invention are shown.

[0032] Figures 7A-7D Different views of a cut-out part in the shape of a general stadium according to an embodiment of the present invention are shown.

[0033] Figures 8A-8D Different views of a generally hexagonal cut part according to an embodiment of the present invention are shown.

[0034] Figures 9A-9D Different views of a generally rectangular cut part according to an embodiment of the present invention are shown.

[0035] Figure 10A-10D Different views of a generally rectangular cutting part with a non-planar diamond stage according to an embodiment of the present invention are shown.

[0036] Figure 11A-11D Different views of a generally rectangular cutting part with a non-planar diamond stage according to an embodiment of the present invention are shown.

[0037] Figure 12A-12D Different views of a generally rectangular cutting part with a non-planar diamond stage according to an embodiment of the present invention are shown.

[0038] Figures 13A-13D Different views of a generally rectangular cutting part with a non-planar diamond stage according to an embodiment of the present invention are shown.

[0039] Figures 14A-14C Different views of a generally rectangular cut part with varying chamfers according to an embodiment of the present invention are shown.

[0040] Figure 15 Different views of a generally rectangular cut part with a shaped non-planar interface according to an embodiment of the present invention are shown.

[0041] Figure 16 Different views of a generally rectangular cut part with a shaped non-planar interface according to an embodiment of the present invention are shown.

[0042] Figure 17 This is an isometric view of a drill bit according to an embodiment of the present invention.

[0043] Figures 18A-18C Different views of a non-cylindrical cut part and a recess according to an embodiment of the present invention are shown.

[0044] Figure 19 A cutting insert with a keyway recess is shown according to an embodiment of the present invention.

[0045] Figure 20 A keyed gasket according to an embodiment of the present invention is shown.

[0046] Figure 21 A keyless gasket according to an embodiment of the present invention is shown.

[0047] Figure 22 A blade with and without a keyed washer is shown according to an embodiment of the present invention.

[0048] Figure 23 A spacer with a non-keyed pad is shown according to an embodiment of the present invention.

[0049] Figure 24 A blade with a spacer and two non-keyed spacers is shown according to an embodiment of the present invention.

[0050] Figure 25 A cutting blade with multiple non-cylindrical cutting elements is shown according to an embodiment of the present invention.

[0051] Figure 26 This is a flowchart illustrating the operation of a method for attaching a cutting part to a cutting part recess according to an embodiment of the present invention.

[0052] Figure 27 This is a flowchart illustrating the operation of a method for manufacturing a drill bit according to an embodiment of the present invention.

[0053] Figure 28 This is a flowchart illustrating the operation of a method for manufacturing a drill bit according to an embodiment of the present invention.

[0054] Figure 29 This is a flowchart illustrating the operation of a method for reorienting a cutting part within a recess in a cutting part according to an embodiment of the present invention.

[0055] Figure 30 This is a flowchart illustrating the operation of a method for operating downhole tools according to an embodiment of the present invention.

[0056] Some of these accompanying drawings are schematic diagrams. It should be understood that these drawings are for illustrative purposes only and should not be considered to be to scale unless otherwise specified. Furthermore, as schematic diagrams, these drawings are provided solely to aid understanding and may not include all aspects or information compared to reality, and may include exaggerations for illustrative purposes. Detailed Implementation

[0057] To meet legal requirements, the subject matter of embodiments of the invention is described in detail herein, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be implemented in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. Except as expressly describing the order of the steps or the arrangement of the elements, this description should not be construed as implying any particular order or arrangement between or among the steps or elements.

[0058] Embodiments of the present invention relate to non-cylindrical cutting elements (e.g., cutting elements with a non-circular cross-sectional shape) and downhole tools including such cutting elements. Using such cutting elements offers numerous advantages compared to conventional cylindrical cutting elements. For example, better point loads can be achieved using non-cylindrical cutting elements. More specifically, non-cylindrical cutting elements may include one or more discrete cutting tips (rather than continuous circular cutting edges), which allows for the application of higher pressures to the rock formation because the same magnitude of force is delivered through a smaller surface area compared to conventional cylindrical cutting elements, thus improving drilling efficiency. Furthermore, the geometry of the non-cylindrical cutting element and the cutting element recess allows the cutting element to self-align within the cutting element recess, so that the cutting tip is positioned in the desired orientation (e.g., cutting position) when the cutting element is inserted into the cutting element recess. This can reduce or eliminate alignment errors associated with manual orientation (e.g., visual inspection or the use of measuring tools) during brazing of the cutting element within the cutting element recess. Furthermore, the presence of multiple discrete cutting tips allows worn cutting parts to be removed from the cutting part recess, rotated, and re-brazed into the recess, with new cutting tips positioned above the top surface of the corresponding insert. This allows cutting parts to be reused for two or more cycles and reduces material waste. Additionally, some or all of the cutting tips of individual cutting parts with multiple discrete cutting tips can have different chamfer or bevel dimensions, which reduces the total inventory of cutting parts used in the organization, further lowering operating costs.

[0059] In some embodiments, the downhole tools described herein may include drill bits, such as rotary scraper bits or hybrid bits, which may include various fixed cutting elements, with or without rotary cutting elements that can destroy formations through shearing or plowing and / or rolling elements that can destroy formations through crushing. Figure 1 An example of a rotary drill bit 100 according to an embodiment of the present disclosure is shown. Figure 1The rotary drill bit 100 is intended as a representative example of a drill bit (e.g., a scraper bit) for drilling into formations. The rotary drill bit 100 is designed to rotate about its central axis 102. The drill bit 100 may include a drill bit body 104 connected to a drill shank 106 having a tapered threaded connector 108 for connecting the drill bit to a drill string (not shown). The drill bit 100 may also include a drill bit loading / unloading surface 111 for cooperating with a wrench to tighten and loosen the connection to the drill string. An outer surface of the drill bit body 104 is intended to face generally in the drilling direction and is referred to as the drill face. This drill face lies generally in a plane perpendicular to the central axis 102 of the drill bit 100. In some embodiments, the drill bit body 104 is made of a wear-resistant composite material or a "metal matrix composite material," which includes, for example, a ceramic component (e.g., powdered tungsten carbide) reinforcing a metal matrix (e.g., a copper alloy matrix). In other embodiments, the drill body 104 may be formed of a metal alloy (e.g., a steel alloy). In some embodiments, all or part of the steel alloy drill body 104 may include a surface-hardening material (e.g., a carbide material) fused to the surface of the steel alloy to provide additional strength to the drill body 104. It should be understood that other materials may also be used to form the drill body 104 in various embodiments.

[0060] During drilling operations, the drill bit 100 can be coupled to the drill string. As the drill bit 100 rotates within the wellbore via the drill string, drilling fluid can be pumped down the drill string, through the internal fluid chambers and fluid passages within the drill bit body 104 of the drill bit 100, and exit from the drill bit 100 through nozzles 117. Cuttings generated by the cutting elements 112 of the drill bit body 104 can be carried by the drilling fluid through fluid passages (e.g., "cutting channels"), around the drill bit 100, and return up the wellbore through the annulus located inside the wellbore and outside the drill string.

[0061] The drill bit body 104 may include one or more protruding blades 110 extending from a face of the drill bit body 104. In some embodiments, the blades 110 extend radially along the drill bit face and are circumferentially spaced structures extending along the front end or formation junction of the drill bit body 104. Each blade 110 extends generally radially outward to the periphery of the drill bit body 104. For example, the blades 110 may extend generally upward from a conical region near the longitudinal axis or central axis 102 of the drill bit to a gauge region or maximum drill diameter of the drill bit. In some embodiments, the blades 110 may be substantially equally spaced around the central axis 102 of the drill bit 100, and each blade 110 may sweep or bend backward in the direction of rotation indicated by arrow 115. In other embodiments, one or more of the blades 110 may have zero sweep (e.g., not bend in the direction of arrow 115). Channels formed between adjacent blades may form chip flutes that provide a path for drilling fluid and cuttings to be carried upward along the wellbore.

[0062] As described above, the drill body 104 also includes a plurality of superhard abrasive cutting elements 112. The cutting elements 112 may be, for example, polycrystalline diamond blank (“PDC”) cutting elements, disposed on the forward-facing surface and / or the top-facing surface of each insert 110. For example, multiple discrete cutting elements 112 may be mounted on each insert 110. The cutting elements 112 may be arranged in a forward helix, reverse helix, skip helix, and / or other cutting element arrangement that defines the radial and angular positions of each cutting element 112. For example, the difference between a skip helix and a forward or reverse helix may be that, even at the nose and shoulder where all secondary inserts are present, radially adjacent cutting elements are not always located on angularly adjacent inserts. In a reverse helix five-insert drill bit, cutting elements 15 to 19 may appear on inserts 1, 5, 4, 3, and 2, respectively. In a skip helix five-insert drill bit, if the size and number of cutting elements are similar, cutting elements 15 to 19 may appear on inserts 1, 4, 5, 2, and 3, respectively. There are many other ways to implement a jump spiral layout.

[0063] Each discrete cutting element 112 may be disposed within a recess or receptacle formed in a given insert 110. The cutting element 112 may be mounted to the drill bit 100 by press-fitting or otherwise locking the column of the corresponding cutting element 112 (e.g., the base portion of the cutting element) into a recess or receiving portion of the scraper drill bit, or by directly brazing a portion of the corresponding cutting element 112 into a pre-formed recess, receptacle, or other receiving portion on the given insert 110. The cutting elements 112 may be arranged in one or more rows along each insert 110. For example, in some embodiments, a given insert 110 may include: one or more primary cutting elements 112 extending through the leading edge of the insert 110; and one or more secondary cutting elements 112 positioned on the insert 110 behind the primary cutting elements 112. In some embodiments, each cutting element 112 may have a unique radial position (i.e., a radial distance from the central axis 102), while in other embodiments, multiple cutting elements 112 (e.g., two or more, three or more, four or more, etc.) may be positioned in a given radial position. In various embodiments, cutting elements located at the same radial position may be mounted on the same blade 110 or on different blades 110. In some embodiments, the outlets of some or all of the nozzles 117 may be aligned with the cutting face of one of the cutting elements facing the corresponding channel, wherein the orientation of the axis of each nozzle 117 is adjusted to be slightly off-parallel (e.g., between 1 and 10 degrees) relative to the front surface of the corresponding blade 110. This allows drilling fluid to more effectively flush cuttings away from the cutting elements 112 while helping to reduce erosion in the area surrounding the cutting recess of the blade 110.

[0064] Figure 2 A view of a face of another embodiment of drill bit 200 is shown. Drill bit 200 may be similar to drill bit 100 and may include any of the features described with respect to drill bit 100. Drill bit 200 has multiple cutting elements (PDC or other types) mounted on multiple inserts. This particular embodiment has six inserts, three of which are primary inserts 226. The other three are secondary inserts 236. The primary inserts extend from near the center of the rotation axis 202, through a conical region, a nose region, and a shoulder region, to the gauge region of drill bit 200. In this example, each primary insert 226 is an offset insert. Each secondary insert 236 extends from the nose region of drill bit 200, through a shoulder region, and then to the gauge region of drill bit 200. The secondary inserts 236 are not offset. In alternative embodiments, one or more of the inserts may be conventional non-offset inserts. The various features or aspects of the improvements disclosed herein are not limited to drill bits having a specific size or number of cutting elements or inserts, unless otherwise expressly stated.

[0065] Conventional inserts have a curved leading edge, where the leading wall transitions to the top surface of the insert, and the main cutting element is mounted along this leading edge. However, each biased insert has a significant step or retraction at its leading edge, where it transitions from a first inner region to a second outer region. The distal end of the leading edge in the inner region is rotated or angularly offset relative to the proximal end of the leading edge in the outer region, forming a step or offset such that the difference in angular position between the last cutting element (the radially furthest cutting element) in the inner region and the first cutting element in the outer region is much greater than the difference in angular positions between the last two cutting elements in the inner region and the first two cutting elements in the outer region. In the illustrated embodiment, each biased insert 226 is continuous, with no gaps in the wall of the biased insert. However, in alternative embodiments, a small gap may be formed between the inner and outer regions.

[0066] As shown, each biasing insert 226 has seven cutting elements 212-224 (although other numbers of cutting elements may be used in various embodiments), which are the main cutting elements. The cutting elements 212-224 are mounted along the leading edge of the biasing insert, adjacent to one of the channels or chip grooves 234 extending along the length of the biasing insert. The biasing insert 226 may also have cutting elements in the gauge protection region of the drill bit 200, which are not visible in this embodiment view. In this example, each biasing insert 226 is a continuous insert with a bias portion along the face or front wall of the insert geometry. In this embodiment, the bias portion is located between cutting elements 216 and 218. The bias portion creates two blade regions: a first (or inner) blade region closer to the centerline or axis of rotation 202 of the drill bit 200, which extends through the conical region of the drill bit 200 to the bias portion; and a second (or outer) region extending from the bias portion, through the nose and shoulder regions of the drill bit 200, to the gauge region of the drill bit. The proximal end of the outer region is radially (outward from the axis of rotation) and angularly displaced from the distal end of the inner region. In this example, the bias portion in the bias blade 226 appears approximately at the location where the conical region of the drill bit transitions to the nose region of the drill bit 200. However, in other embodiments, the bias portion may appear in or near other regions of the drill bit 200, such as the nose or shoulder, or the transition from nose to shoulder. Furthermore, alternative embodiments of the drill bit may have one or more or all of the bias blades with more than one bias portion and varying numbers of bias portions. For example, a biasing insert may have three parts: a first part, a second part, and a third part, wherein the first biasing part is between the first two parts, and the second biasing part is between the second and third parts. Furthermore, one or more biasing inserts on a drill bit may have one biasing part; one or more other biasing inserts may have two biasing parts. One or more additional biasing inserts on a drill bit may have three or more biasing parts.

[0067] Secondary inserts 236 can be used to increase the cutting density in the nose and shoulder of the drill bit. Cuttings in these areas typically perform most of the work in forming the wellbore. As the drill bit advances downhole, more material needs to be removed from the borehole in these areas compared to the conical areas because these areas have a wider radius, resulting in a larger surface area of ​​rock to be removed. Secondary inserts allow for a balance between the number of cuttings exposed in the area and the area of ​​rock to be removed from that area. Each of the secondary inserts has four primary cuttings 238-244 (visible in this view) and may also have cuttings in the gauge area of ​​the drill bit 200 (obscured and not visible). Cuttings 238-244 are fixed in position on the drill bit 200. The fixed position of a particular cutting is defined by the insert on which it is mounted, the axial distance from the center of rotation of the drill bit 200, and the relative radial position of the cutting on the face of the drill bit 200.

[0068] The drill bit 200 may include a plurality of nozzles 228-232 located in a plurality of channels or chip flutes 234. The chip flutes 234 may be located in front of each blade and defined by the rear wall of the blade and the front wall of the next blade (based on the rotation direction of the drill bit 200). The nozzles 228-232 guide drilling fluid pumped through the drill string (not shown) toward the cuttings to flush cuttings off the faces of the drill bit 200. The chip flutes 234 create spaces for collecting and discharging cuttings, wherein the chip flutes guide drilling fluid and cuttings radially outward and then upward through the gauge area into the annulus between the wellbore sidewall and the drill string (not shown).

[0069] Nozzle 230 is located in front of the inner region of bias blade 226. The drilling fluid flowing from each nozzle 230 is primarily intended to remove cuttings detached from the primary cutting elements mounted along the leading edge of the inner region of each bias blade 226, in this example, cutting elements 212, 214, and 216. The drilling fluid flowing from each nozzle 230 is secondary intended to provide cooling and manage the operating temperature of the primary cutting elements mounted along the leading edge of the inner region of each bias blade 226, in this example, cutting elements 212, 214, and 216. Therefore, nozzle 230 is directed such that drilling fluid flows across the faces of these cutting elements 212-215 and downwards into a chip removal channel 234 located between the front of the bias blade 226 and the back side of the secondary blade 236 located in front of the bias blade 226.

[0070] Each nozzle 228 is inserted into a corner formed in the front wall of the blade formed by the bias portion in the bias blade 226. Each nozzle 228 guides drilling fluid along the outer region of each of the bias blades 226 toward the faces of the cutting elements 218, 220, 222 and 224, which are the main cutting elements mounted along the leading edge of the outer region of the bias blade 226.

[0071] Nozzle 228 is rearward and radially outwardly rotated and biased relative to nozzle 230. Because each nozzle 228 is rotated and displaced relative to nozzle 230, the fluid flowing from each nozzle 228 tends not to interfere with the fluid flow from nozzle 230, or the degree of interference is much less than if nozzle 228 were not rotated and displaced. Nozzle 230 is oriented such that drilling fluid from nozzle 230, after flowing over the faces of cutting elements 212, 214, and 218 in the inner region of biased blade 226, tends to flow primarily along with rock cuttings generated by these cutting elements through the region between the back of secondary blade 236 and nozzle 228. The fluid flowing from nozzle 228 primarily flows over the faces of cutting elements 218, 220, 222, and 224, and then continues into the annulus of the borehole along the front wall or leading edge of the second blade portion of biased blade 226.

[0072] The offset cutting edge 226 and secondary cutting edge 236 of drill bit 200 may include inclined surfaces 246 and 248, respectively, on the back of the cutting edge, located behind the cutting element arranged along the leading edge of the cutting edge. The cutting surface of the drill bit 200 body, particularly the top surface of the cutting edge, serves to limit the penetration of the cutting element into the formation. The primary cutting element extends above the top of the cutting edge or other features or aspects of the drill bit that limit the depth into the rock by which the primary cutting element can penetrate; this is referred to as the cutting element exposure. Generally, a higher exposure will allow the primary cutting element to penetrate deeper into the formation, which can increase the drill bit's drilling rate (ROP) to extend the borehole. On the other hand, if the primary cutting element exposure is too high, other problems may occur, which may reduce the drilling rate or cause premature failure of the cutting element, ultimately resulting in drill bit damage or failure. Therefore, the exposure is selected to optimize the drilling rate while maintaining an acceptable level of reliability. At high drilling rates, the rear portion of the cutting edge's top surface may contact the formation before the front portion, leading to increased friction and potentially shallower drilling depths than otherwise achieved by the bit. Inclined surfaces 246 and 248 remove a portion of the cutting edge without substantially weakening it, as the rear of each cutting edge might otherwise contact the formation during high drilling rates. In addition to inclined surfaces, steps or a series of steps could be used as alternatives, but this would likely come at the cost of increased manufacturing complexity and / or weaker cutting edges.

[0073] In some embodiments, the downhole tool described herein may include a reamer. Figure 3A reamer 300 for drilling operations is illustrated according to certain embodiments. The reamer 300 may include an upper shaft 302a, a lower shaft 302b, a body 304, and inserts 314a-314c disposed around the body 304. Each insert 314a-314c may be separated by channels or “chip grooves.” Each insert 314a-314c may include one or more cutting elements 316, which in some embodiments may be PDC cutting elements. For example, each cutting element 316 may include a matrix and a diamond stage. The matrix may be made of a carbon- and metallic material, such as a carbide containing titanium, iron, tungsten, and other suitable metals. The diamond stage may include a polycrystalline diamond surface as described above. Each cutting element 316 may be inserted into a hollow recess included in the corresponding insert 314. This hollow recess (or “recess”) may be formed into the reamer 300 during manufacturing by machining, casting, and / or other means. Each cutting element 316 can be configured such that it corresponds to a specific recess included in the corresponding insert 314. For example, the size and shape of each cutting element 316 can be substantially matched with the size and shape of the corresponding recess that receives the cutting element 316 (e.g., with an error of about 0.025 inches or less, to provide a brazing gap for receiving the brazing alloy that connects the cutting element to the insert).

[0074] The reamer 300 can be used to (at least partially) widen a pre-existing hole or cavity. For example, the pre-existing hole or cavity can be created to a first width by a drill bit similar to drill bits 100 and 200. The reamer 300 is then inserted into the pre-existing hole or cavity to widen it. As the reamer 300 rotates within the pre-existing hole or cavity, the cutting element 316 can cause material (e.g., soil, rock, etc.) to be removed from the hole or cavity.

[0075] Although the reamer 300 is shown as having blades 314a-314c vertically positioned between the upper shaft 302a and the lower shaft 302b and rotating axially relative to the reamer 300, other configurations are possible. For example, the blades 314a-314c may be vertically positioned between the upper shaft 302a and the lower shaft 302b but not rotating (parallel to the vertical axis of the reamer 300). In another example, the blades 314a-314c may be arranged around the circumference of the reamer 300. The reamer 300 can be a slot reamer, a wing reamer, an eccentric reamer, a barrel reamer, and / or any other suitable reamer.

[0076] In yet another example, the reamer 300 may be an expandable reamer. In such an embodiment, the blades 314a-314c may be enclosed within a housing. During operation, the housing may be opened, allowing the blades 314a-314c to extend radially outward from the reamer 300, thereby engaging the cutting element 316 with the formation. In yet another example, during non-operational periods, the blades 314a-314c may be in a first position in which the cutting element 316 is not exposed to the formation. During operation, the blades 314a-314c may rotate and / or extend to a second position in which the cutting element 316 engages the formation. Those skilled in the art will appreciate many different possibilities and configurations.

[0077] As described above, the downhole tools described herein may include cutting elements used to engage and remove portions of drilled formations. Each cutting element may include a highly wear-resistant cutting surface or wear-resistant surface made of polycrystalline diamond (PDC) or similar highly wear-resistant materials. PDC cutting elements are typically made by forming a polycrystalline diamond layer (sometimes called a crown or diamond stage) on a carbide matrix (e.g., a tungsten carbide matrix), which in some embodiments may also include one or more additional metal additives. The PDC wear-resistant surface may be formed from sintered polycrystalline diamond (natural or synthetic) exhibiting diamond-diamond bonding. Polycrystalline cubic boron nitride, wurtzite boron nitride, polymeric diamond nanotubes (ADN), or other hard crystalline materials are known alternative materials and / or additives and may be useful in some drilling applications. The mixture of powdered diamond abrasive material with or without one or more powdered metal catalysts and other materials / additives can be shaped into a billet, which is then typically sintered with a tungsten carbide matrix under high temperature and pressure. For the purposes described below, sintered billets of polycrystalline cubic boron nitride, wurtzite boron nitride, ADN, and similar materials are equivalent to polycrystalline diamond billets, and therefore, references to “PDC” in the detailed description should be understood as referring to sintered billets of polycrystalline diamond, cubic boron nitride, wurtzite boron nitride, and other highly wear-resistant materials, unless otherwise expressly stated or the context does not permit. References to “PDC” are also intended to include sintered billets of these materials with other materials or structural elements that may be used to improve their performance and cutting characteristics. Furthermore, PDC also includes thermally stabilized variants in which the metal catalyst has been partially or completely removed after sintering. Such PDC cutting parts may also include “secondary pressing” cutting parts, which involve sintering a diamond stage onto a planar or non-planar substrate, as will be discussed in more detail below.

[0078] The substrate used to support the wear-resistant surface or layer of PDC is typically made at least partially of cemented metal carbide, with tungsten carbide being the most common. The cemented metal carbide substrate can be formed by sintering powdered metal carbides with a metal alloy binder. Composite materials of PDC and substrate can be manufactured in a variety of different ways. For example, the composite material may also include a transition layer in which metal carbides and diamond are mixed with other elements to improve the bonding between the PDC and the substrate and reduce stress.

[0079] Each PDC cutting part can be manufactured as a discrete component separate from the downhole tool. Due to the processes used to manufacture them, the polycrystalline diamond layer and matrix typically have a cylindrical shape, with relatively thin polycrystalline diamond disks bonded to a taller or longer cylinder of the matrix material. The resulting composite material can be used as a conventional cutting part in a cylindrical shape, or it can be machined or otherwise formed into a desired non-cylindrical shape. In other embodiments, the matrix and / or diamond stage can be pressed or otherwise formed into a non-cylindrical shape, and may or may not require machining to achieve the desired non-cylindrical shape.

[0080] Compared to traditional cylindrical cutting elements, incorporating non-cylindrical cutting elements into downhole tools such as drill bits and reamers offers numerous advantages. For example, non-cylindrical cutting elements can include multiple discrete cutting tips that achieve better point loads and can improve drilling efficiency. Furthermore, the non-cylindrical carbide matrix can reduce or eliminate friction between the matrix and the downhole formation at medium to high cutting depths, thereby eliminating matrix bearing surfaces that can lead to decreased drilling speeds and / or premature cutting element failure due to thermal breakdown. Additionally, the geometry of the non-cylindrical cutting element and its cutting element recess allows for self-alignment within the recess, ensuring that the cutting tip is positioned in the desired orientation (e.g., cutting position) when the cutting element is inserted into the recess. Moreover, the presence of multiple discrete cutting tips allows for the removal, rotation, and re-brazing of worn cutting elements from the recess, with new cutting tips positioned above the top surface of the corresponding insert. This allows the cutting element to be reused for two or more cycles and reduces material waste.

[0081] Figure 4A-16 An embodiment of a non-cylindrical cutting element according to the present invention is shown. The non-cylindrical cutting element can be used as some or all of the cutting elements 112 and 212-224 in drill bits 100 and 200, and / or can be used as some or all of the cutting elements 316 in reamer 300. Each non-cylindrical cutting element can be a PDC cutting element and can include a base for mounting the cutting element within a recess in a downhole tool and a diamond station for engaging the cutting formation. Figures 4A-4D A non-cylindrical cutting element 400 according to certain embodiments is shown. The cutting element 400 may include a body formed by a base 402 and a diamond stage 404 coupled to the base 402. The cutting element 400 may include a central axis 410 extending along the length of the cutting element 400. The base 402 may include a base 406, a top surface (not shown) on which the diamond stage 404 may be mounted, and one or more lateral surfaces 408 extending between the base 406 and the top surface. Similarly, the diamond stage 404 may include a base (not shown), a top cutting face 412, and one or more lateral surfaces 414 extending between the base and the cutting face 412. As shown, the cutting face 412 is planar and parallel to the base 406, but in some embodiments, the cutting face 412 may include one or more relief features and / or may be angled relative to the base 406, as will be described in more detail below.

[0082] The substrate 402 may include a brazing surface, which may include all or part of one or more lateral surfaces 408 and a base 406. The brazing surface may include a portion of the outer surface of the substrate 402 that may be brazed to a cutting recess of a downhole tool, such as a portion of the lateral surfaces 408 and / or the base 406 that contacts and / or is received within the cutting recess. In other words, the brazing surface or brazable surface region may include all surfaces corresponding to and / or directly facing the walls defining the cutting recess. In some embodiments, at least a portion of the brazing surface, the substrate 402, and / or the diamond stage 404 may have a non-circular cross-section. For example, the radial distance between the lateral surfaces 408 and / or 414 and the central axis 410 may vary around the periphery of the body of the cutting tool 400. The radial distance between the lateral surfaces 408 and / or 414 of the cutting element 400 and the central axis 410 may vary along at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more of the outer periphery of the cutting element 400. The radial distance between the lateral surfaces 408 and / or 414 of the cutting element 400 and the central axis 410 may vary along at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or more of the length of the body and / or base 402. In other words, the cross-section of the base 402 and / or body of the cutting element 400 may be non-circular for at least 75% of the length of the body and / or base 402. In some embodiments, only the substrate 402 (or a portion thereof) has a non-circular cross-section, while in other embodiments, both the substrate 402 and the diamond stage 404 (or portions of one or both components) may have non-circular cross-sections. As used herein, the term cross-sectional shape should be understood to refer to the cross-sectional shape of a given cutting element or cutting recess taken along a plane extending through the width of the cutting element or cutting recess and orthogonal to the longitudinal axis of the cutting element or cutting recess.

[0083] To produce a non-circular cross-section, instead of an arc with a constant radius relative to the central axis 410, the cutting element 400 may include a plurality of different lateral surfaces 408 and / or 414, wherein at least one lateral surface 408 and / or 414 does not have an arc with a constant radius relative to the central axis 410. For example, the cutting element 400 may include one or more lateral surfaces 408 and / or 414 that are planar and connected by one or more corners, which may be sharp or rounded in various embodiments. In other embodiments, one or more lateral surfaces may be rounded, such as convex or concave surfaces. In the illustrated embodiment, both lateral surfaces 408 and 414 include four planar or linear lateral surfaces 408a and 414a that are connected at four corners 408b and 414b to form a generally quadrilateral shape (e.g., a quadrilateral with rounded corners). As shown in the figure, the linear lateral surfaces 408a and 414a are arranged as two pairs of parallel surfaces, which are orthogonal to each other to form a generally rectangular cross-section. However, in other embodiments, the linear lateral surfaces 408a and / or 414a may be at other angles to form rhombuses, trapezoids, parallelograms, and / or other quadrilaterals. In some embodiments, each linear lateral surface 408a and 414a may have the same length to create a square-shaped cutting part 400. In other embodiments, one pair of opposing linear lateral surfaces 408a and 414a may be longer than the other pair of linear lateral surfaces 408a and 414a, which can achieve rectangular and / or rhomboid cutting parts 400. In other embodiments, individual linear lateral surfaces 408a and 414a in one or both pairs of opposing linear lateral surfaces may have different lengths, thereby enabling the formation of asymmetrical cutting parts 400.

[0084] As shown in the figure, corners 408b and 414b are rounded, which helps reduce the magnitude of the pressure applied to corners 408b and 414b when the cutting element 400 engages the cutting layer. The radius of each corner 408b and 414b can be varied or constant. For example, a constant radius can be used such that each corner 408b and / or 414b is the same throughout the entire corner 408b and / or 414b. In some embodiments, the radius of each corner 408b and 414b can match the radius of the circle whose diameter extends between the opposing corners 408b and 414b; however, in various embodiments, larger or smaller radii can be used to form gentler or sharper corners.

[0085] The widths of each corner 408b and 414b can vary based on desired point loads and drilling efficiency, while ensuring the cutter 400 has sufficient durability to withstand downhole operating conditions. For example, narrower and / or sharper corners 408b and 414b can improve the point load and drilling efficiency of the cutter 400. However, a minimum width is required to ensure the cutter 400 is robust enough to withstand a given number of downhole operations, such as drilling or reaming. In a particular embodiment, the width of each corner 408b and 414b, measured relative to the central axis 410, can be between 5 degrees and 45 degrees.

[0086] Each corner 414b of the diamond platform 404 can form a discrete cutting tip of the cutting face 412, which can be positioned on the cutting tool's insert in a cutting position such that the cutting tip protrudes beyond the top surface of the insert. This positions the corner 414b of the diamond platform 404 such that the corner 414b engages the cutting formation before a portion of the insert, and as the downhole tool rotates within the borehole, the corner 414b can break the rock or other material forming the cutting formation. Additionally, the presence of one or more lateral surfaces 408 having non-constant arcs (e.g., linear and / or varying and / or concave arcs) allows such lateral surfaces 408 to serve as indexing features that can be used to orient the cutting element 400 in a corresponding cutting recess in a cutting position where the cutting tip of the cutting element 400 protrudes beyond the top surface of the insert at a desired angle relative to the top and / or front surface of the insert.

[0087] The diamond stage 404 may include a chamfered edge 416 extending from the cutting face 412 to the lateral side 414 of the diamond stage 404. For example, the chamfered edge 416 may extend from the cutting face 412 to the lateral side 414 at an angle between 20 and 60 degrees relative to the cutting face 412. The chamfered edge 416 can reduce the pressure exerted on the diamond stage 404 by the cutting formation and can help improve the durability of the workpiece 400. The angle of the chamfered edge 416 can be selected to control cutting intrusion and / or the durability of the workpiece 400.

[0088] although Figures 4A-4D A non-cylindrical cutting element with a generally quadrilateral cross-section is shown; however, it should be understood that in various embodiments, the non-cylindrical cutting element may also take other shapes. For example, the diamond stage and / or each non-cylindrical cutting element may have two or more linear lateral surfaces (and / or concave sides), three or more linear lateral surfaces, four or more linear lateral surfaces, five or more linear lateral surfaces, or more linear lateral surfaces. For example, Figures 5A-5DA non-cylindrical cutting element 500 with a generally triangular cross-section is shown. Besides the generally cross-sectional shape, the cutting element 500 may also include features similar to those of the cutting element 400. For example, the cutting element 500 may include a body formed by a base 502 and a diamond stage 504 coupled to the base 502. The cutting element 500 may include a central axis 510 that may extend along the length of the cutting element 500. The base 502 may include a base 506, a top surface (not shown) on which the diamond stage 504 may be mounted, and lateral surfaces 508 extending between the base 506 and the top surface. Similarly, the diamond stage 504 may include a base (not shown), a top cutting face 512, and three lateral surfaces 514 extending between the base and the cutting face 512. In the illustrated embodiment, both lateral surfaces 508 and 514 comprise three planar or linear lateral surfaces 508a and 514a, which connect at three corners 508b and 514b to form a generally triangular shape (e.g., a triangle with rounded corners). As shown, the corners 508b and 514b are rounded, which helps reduce the magnitude of the pressure applied to the corners 508b and 514b when the cutting element 500 engages the cutting formation. The radius of each corner 508b and 514b can be varied or constant. For example, a constant radius can be used such that each corner 508b and / or 514b is identical throughout the entire corner 508b and / or 514b. In some embodiments, the radius of each corner 508b and 514b may match the radius of a circle whose diameter extends between the opposing corners 508b and 514b; however, larger or smaller radii may be used in various embodiments to form gentler or sharper corners. The diamond stage 504 may include a chamfered edge 516 extending from the cutting face 512 to the lateral side 514 of the diamond stage 504. For example, the chamfered edge 516 may extend from the cutting face 512 to the lateral side 514 at an angle between 20 and 60 degrees relative to the cutting face 512.

[0089] Each corner 514b of the diamond platform 504 can form a discrete cutting tip of the cutting face 512, which can be positioned on the cutting tool's insert in a cutting position such that the cutting tip protrudes beyond the top surface of the insert. This positions the corner 514b of the diamond platform 504 such that the corner 514b contacts the cutting formation before a portion of the insert, and that as the downhole tool rotates within the borehole, the corner 514b can break the rock or other material forming the cutting formation. Additionally, the presence of one or more lateral surfaces 408 having non-constant arcs (e.g., linear and / or varying and / or concave arcs) allows such lateral surfaces 508 to serve as indexing features that can be used to orient the cutting element 500 in a corresponding cutting recess into a cutting position in which the cutting tip of the cutting element 500 protrudes beyond the top surface of the insert at a desired angle relative to the top and / or front surface of the insert.

[0090] Figures 6A-6DA non-cylindrical cutting element 600 with a generally pentagonal cross-section is shown. Besides the generally cross-sectional shape, the cutting element 600 may include features similar to those of cutting elements 400 and 500. For example, the cutting element 600 may include a body formed by a base 602 and a diamond stage 604 coupled to the base 602. The cutting element 600 may include a central axis 610 that may extend along the length of the cutting element 600. The base 602 may include a base 606, a top surface (not shown) on which the diamond stage 604 may be mounted, and five lateral surfaces 608 extending between the base 606 and the top surface. Similarly, the diamond stage 604 may include a base (not shown), a top cutting face 612, and lateral surfaces 614 extending between the base and the cutting face 612. In the illustrated embodiment, both lateral surfaces 608 and 614 comprise five planar or linear lateral surfaces 608a and 614a, which connect at five corners 608b and 614b to form a generally pentagonal shape (e.g., a pentagon with rounded corners). As shown, the corners 608b and 614b are rounded, which helps reduce the magnitude of the pressure applied to the corners 608b and 614b when the cutting element 600 engages the cutting formation. The radius of each corner 608b and 614b can be varied or constant. For example, a constant radius can be used such that each corner 608b and / or 614b has the same radius throughout its entirety. In some embodiments, the radius of each corner 608b and 614b may match the radius of a circle whose diameter extends between the opposing corners 608b and 614b; however, larger or smaller radii may also be used in various embodiments to form gentler or sharper corners. The diamond stage 604 may include a chamfered edge 616 extending from the cutting face 612 to the lateral side 614 of the diamond stage 604. For example, the chamfered edge 616 may extend from the cutting face 612 to the lateral side 614 at an angle between 20 and 60 degrees relative to the cutting face 612.

[0091] Each corner 614b of the diamond platform 604 can form a discrete cutting tip of the cutting face 612, which can be positioned on the cutting edge of the downhole tool such that the cutting tip protrudes beyond the top surface of the cutting edge. This positions the corner 614b of the diamond platform 604 such that the corner 614b engages the cutting formation before a portion of the cutting edge, and that as the downhole tool rotates within the borehole, the corner 614b can break the rock or other material forming the cutting formation. Additionally, the presence of one or more lateral surfaces 608 having non-constant arcs (e.g., linear and / or having varying and / or concave arcs) allows such lateral surfaces 608 to serve as indexing features that can be used to orient the cutting edge 600 in a corresponding cutting edge recess in a cutting position in which the cutting tip of the cutting edge 600 protrudes beyond the top surface of the cutting edge at a desired angle relative to the top and / or front surface of the cutting edge.

[0092] Figures 7A-7DA non-cylindrical cutter 700 with a cross-section generally resembling a stadium is shown. In some embodiments, cutter 700 may have a true stadium shape, wherein two semicircular regions are separated by a central rectangular region whose width matches the diameter of the semicircular regions. In such embodiments, the transition between the semicircular and rectangular regions may be seamless. In other embodiments, cutter 700 may have a generally stadium shape with two arcuate regions, each arcuate region having a circle less than 180 degrees, separated by a central rectangular region whose width is less than the diameter of the semicircular regions. In such embodiments, the transition between the semicircular and rectangular regions may form a corner, which may be rounded or sharp. In addition to the generally cross-sectional shape, cutter 700 may include features similar to those of cutters 400, 500, and 600. For example, cutter 700 may include a body formed by a base 702 and a diamond platform 704 coupled to the base 702. Cutter 700 may include a central axis 710 that may extend along the length of cutter 700. The base 702 may include a base 706, a top surface (not shown) on which a diamond stage 704 may be mounted, and a lateral surface 708 extending between the base 706 and the top surface. Similarly, the diamond stage 704 may include a base (not shown), a top cutting face 712, and a lateral surface 714 extending between the base and the cutting face 712. In the illustrated embodiment, both lateral surfaces 708 and 714 include two planar or linear lateral surfaces 708a and 714a connected by two rounded ends 708b and 714b to form a stadium shape. The radius of each rounded end 708b and 714b may be varied or constant. For example, a constant radius may be used such that each rounded end 708b and / or 714b has the same radius throughout its entirety. In some embodiments, the radius of each rounded end 708b and 714b may match the radius of the circle whose diameter extends between the two rounded ends 708b and 714b; however, larger or smaller radii may be used in various embodiments to form a smoother or sharper end. The diamond stage 704 may include a chamfered edge 716 extending from the cutting face 712 to the lateral side 714 of the diamond stage 704. For example, the chamfered edge 716 may extend from the cutting face 712 to the lateral side 714 at an angle between 20 and 60 degrees relative to the cutting face 712.

[0093] Each rounded end 714b of the diamond station 704 can form a discrete cutting tip of the cutting face 712, which can be positioned on the cutting edge of the downhole tool such that the cutting tip protrudes beyond the top surface of the cutting edge. This positions the rounded end 714b of the diamond station 704 such that the rounded end 714b engages the cutting formation before a portion of the cutting edge, and as the downhole tool rotates within the borehole, the rounded end 714b can break the rock or other material forming the cutting formation. Additionally, the presence of one or more lateral surfaces 408 having non-constant arcs (e.g., linear and / or having varying and / or concave arcs) allows such lateral surfaces 408 to serve as indexing features that can be used to orient the cutting edge 400 in a corresponding cutting edge recess in a cutting position in which the cutting tip of the cutting edge 400 protrudes beyond the top surface of the cutting edge at a desired angle relative to the top and / or front surface of the cutting edge.

[0094] Figures 8A-8DA non-cylindrical cutting element 800 with a generally hexagonal cross-section is shown. Apart from its generally cross-sectional shape, the cutting element 800 may include features similar to those of cutting elements 400, 500, 600, and 700. For example, the cutting element 800 may include a body formed by a base 802 and a diamond stage 804 coupled to the base 802. The cutting element 800 may include a central axis 810 that may extend along the length of the cutting element 800. The base 802 may include a base 806, a top surface (not shown) on which the diamond stage 804 may be mounted, and a lateral surface 808 extending between the base 806 and the top surface. Similarly, the diamond stage 804 may include a base (not shown), a top cutting face 812, and a lateral surface 814 extending between the base and the cutting face 812. In the illustrated embodiment, both lateral surfaces 808 and 814 comprise six planar or linear lateral surfaces 808a and 814a, which connect at six corners 808b and 814b to form a generally hexagonal shape (e.g., a hexagon with rounded corners). As shown, the corners 808b and 814b are rounded, which helps reduce the magnitude of the pressure applied to the corners 808b and 814b when the cutting element 800 engages the cutting formation. The radius of each corner 808b and 814b can be varied or constant. For example, a constant radius can be used such that each corner 808b and / or 814b has the same radius throughout its entirety. In some embodiments, the radius of each corner 808b and 814b may match the radius of a circle whose diameter extends between the opposing corners 808b and 814b; however, larger or smaller radii may be used in various embodiments to form gentler or sharper corners. The diamond stage 804 may include a chamfered edge 816 extending from the cutting face 812 to the lateral side 814 of the diamond stage 804. For example, the chamfered edge 816 may extend from the cutting face 812 to the lateral side 814 at an angle between 20 and 60 degrees relative to the cutting face 812.

[0095] Each corner 814b of the diamond platform 804 can form a discrete cutting tip of the cutting face 812, which can be positioned on the cutting edge of the downhole tool such that the cutting tip protrudes beyond the top surface of the cutting edge. This positions the corner 814b of the diamond platform 804 such that the corner 814b engages the cutting formation before a portion of the cutting edge, and that as the downhole tool rotates within the borehole, the corner 814b can break the rock or other material forming the cutting formation. Additionally, the presence of one or more lateral surfaces 808 having non-constant arcs (e.g., linear and / or having varying and / or concave arcs) allows such lateral surfaces 808 to serve as indexing features that can be used to orient the cutting edge 800 in a corresponding cutting edge recess in a cutting position in which the cutting tip of the cutting edge 800 protrudes beyond the top surface of the cutting edge at a desired angle relative to the top and / or front surface of the cutting edge.

[0096] Figures 9A-9DA non-cylindrical cutting element 900 with a generally rectangular cross-section is shown, having concave, non-linear lateral surfaces. Apart from its general cross-sectional shape, the cutting element 900 may include features similar to those of cutting elements 400, 500, 600, 700, and 800. For example, the cutting element 900 may include a body formed by a base 902 and a diamond stage 904 coupled to the base 902. The cutting element 900 may include a central axis 910 extending along its length. The base 902 may include a base 906, a top surface (not shown) on which the diamond stage 904 may be mounted, and a lateral surface 908 extending between the base 906 and the top surface. Similarly, the diamond stage 904 may include a base (not shown), a top cutting face 912, and a lateral surface 914 extending between the base and the cutting face 912. In the illustrated embodiment, both lateral surfaces 908 and 914 include four concave lateral surfaces 908a and 914a, which connect at four corners 908b and 914b to form a generally rectangular shape (e.g., a rectangle with inwardly curved sides and rounded corners). In some embodiments, each concave lateral surface 908a and 914a may have a constant radius or a varying radius. It will also be understood that in some embodiments, instead of having concave lateral surfaces, the cutting element 900 may have convex lateral surfaces. As shown, the corners 908b and 914b are rounded, which helps reduce the magnitude of the pressure applied to the corners 908b and 914b when the cutting element 900 engages the cutting formation. The radius of each corner 908b and 914b may be varying or constant. For example, a constant radius may be used such that each corner 908b and / or 914b has the same radius throughout the entire corner 908b and / or 914b. In some embodiments, the radius of each corner 908b and 914b may match the radius of a circle whose diameter extends between the opposing corners 908b and 914b; however, larger or smaller radii may be used in various embodiments to form gentler or sharper corners. The diamond stage 904 may include a chamfered edge 916 extending from the cutting face 912 to the lateral side 914 of the diamond stage 904. For example, the chamfered edge 916 may extend from the cutting face 912 to the lateral side 914 at an angle between 20 and 60 degrees relative to the cutting face 912.

[0097] Each corner 914b of the diamond platform 904 can form a discrete cutting tip of the cutting surface 912, which can be positioned on the cutting edge of the downhole tool such that the cutting tip protrudes beyond the top surface of the cutting edge. This positions the corner 914b of the diamond platform 904 such that the corner 914b engages the cutting formation before a portion of the cutting edge, and as the downhole tool rotates within the borehole, the corner 914b can break the rock or other material forming the cutting formation. Additionally, the presence of one or more lateral surfaces 908 having non-constant arcs (e.g., linear and / or with varying and / or concave arcs) allows such lateral surfaces 908 to serve as indexing features that can be used to orient the cutting edge 900 in a corresponding cutting edge recess in a cutting position in which the cutting tip of the cutting edge 900 protrudes beyond the top surface of the cutting edge at a desired angle relative to the top and / or front surface of the cutting edge.

[0098] Although each cutting element shown has a regularly shaped cross-section, it should be understood that cutting elements with irregularly shaped cross-sections may be used in various embodiments. Additionally, a cutting element according to the invention may include a circular cross-section along a portion of the length of the cutting element, wherein the cross-section transitions to one or more non-circular shapes that collectively extend at least 75% of the length of the cutting element. Similarly, in some embodiments, the cross-sectional shape of all or part of the diamond stage may differ from the cross-sectional shape of part or all of the matrix of the cutting element. Typically, the cross-sectional shape of the cutting element (or a portion thereof) may be formed by two or more linear lateral surfaces connected to each other by multiple rounded corners or rounded ends. In such embodiments, the ratio of the length of the linear lateral surface to the length of the rounded corners / rounded ends (e.g., the ratio of the outer perimeter of the non-circular cross-section formed by the straight surface to the outer perimeter of the curved surface) can be between 0.5:1 and 10:1, between 0.5:1 and 5:1, between 0.5:1 and 4:1, between 0.5:1 and 3:1, between 0.5:1 and 2.5:1, between 0.5:1 and 2:1, between 0.5:1 and 1.5:1, between 0.5:1 and 1:1, or between 0.5:1 and 0.75:1. In some embodiments, the non-cylindrical cutting element described herein can be symmetrical about one or more planes or axes. For example, the cutting element can be symmetrical about two vertical planes extending through both the matrix and the diamond stage. For example, this could be the case for rectangular cutting parts such as cutting part 400, hexagonal cutting parts such as cutting part 800, rectangular cutting parts such as cutting part 900 with concave sides, and stadium-shaped cutting parts such as cutting part 700. Specifically, cutting part 400 may be symmetrical about two vertical planes that bisect different pairs of opposing lateral surfaces 408a and 414a, and / or about two vertical planes that bisect different pairs of opposing corners 408b and 414b. In other embodiments, the cutting parts may be asymmetrical and / or symmetrical about two or more planes that are not orthogonal to each other, for example, triangular cutting part 500 and pentagonal cutting part 600.

[0099] In some embodiments, instead of such Figure 4A-9DThe diamond stage shown has a planar cutting surface, and the cutting element may include a diamond stage with a non-planar cutting surface. For example, the cutting surface may include one or more release features, such as protruding features extending in a direction opposite to the matrix and / or recessed features extending toward the matrix. The inclusion of release features can be used for various purposes. For example, a protruding release feature can increase the thickness of the diamond stage to enhance the strength of the cutting element, while also improving the point load of the cutting element because the cutting tip protrudes away from the rest of the diamond stage to engage the formation before any other part of the cutting element. A recessed release feature located in a region near the cutting tip but not extending through the cutting tip can similarly improve the point load by extending the cutting tip away from the surrounding portion of the diamond stage. Figure 10A-12D Different embodiments of a cutting workpiece having a non-planar cutting surface according to the present technology are shown. (Turn) Figure 10A-10D A rectangular cutting element 1000 is shown. The cutting element 1000 may be similar to the rectangular cutting element 400 and may include any of the features described with respect to the cutting element 400. For example, the cutting element 1000 may include a body formed by a diamond platform 1004 coupled to a base 1002. The diamond platform 1004 may include a cutting surface configured to engage cutting formations during downhole operations. The cutting surface 1012 of the diamond platform 1004 may include one or more release features that protrude away from and / or recess toward the base 1002. For example, as shown, the diamond platform 1004 includes a ridge 1020 extending from one corner of the cutting surface 1012 to an opposite corner of the cutting surface 1012. In various embodiments, the ridge 1020 may have a flat top, an angled top, and / or a curved top. The ridge 1020 is a protruding feature that extends in the opposite direction to the base 1002, thereby increasing the thickness of the diamond stage 1004 at the corner through which the ridge 1020 extends. The thickness of the diamond stage 1004 can taper from its thinnest point near the corner not containing the ridge 1020 to its thickest point at the top of the ridge 1020, or otherwise vary. The taper can be linear as shown herein, or it can be curved and / or stepped as in some embodiments. The thickness difference between the thickest and thinnest regions of the diamond stage 1004 can be between 0.005 inches and 0.300 inches, wherein the total thickness of the diamond stage 1004 is between 0.050 inches and 0.350 inches.

[0100] Figure 11A-11DAn embodiment of a rectangular cutting element 1100 having multiple release features is shown. The cutting element 1100 may be similar to rectangular cutting elements 400 and 1000 and may include any of the features described with respect to cutting elements 400 and 1000. For example, the cutting element 1100 may include a body formed by a base 1102 and a diamond platform 1104 associated with the base 1102. The diamond platform 1104 may include a cutting surface configured to engage a cutting formation during downhole operations. The cutting surface 1112 of the diamond platform 1104 may include one or more release features that protrude away from and / or recess toward the base 1102. For example, as shown, the diamond platform 1104 includes two ridges 1120, each extending from one corner of the cutting surface 1112 to an opposite corner of the cutting surface 1112. Each ridge 1120 is a protruding feature extending in the opposite direction to the base 1102, thereby increasing the thickness of the diamond stage 1104 at the corner through which each ridge 1120 extends. Two ridges 1120 may intersect at the center of the cutting surface 1112, forming the thickest region of the diamond stage 1104. For example, the thickness of the diamond stage 1104 may taper or otherwise change from a thinnest point near the midpoint of a linear lateral surface extending between adjacent corners of the diamond stage 1104 to a thickest point at the top of each ridge 1120. This taper may be linear and may create a V-shaped valley between each pair of adjacent corners of the diamond stage 1104, as shown herein, or in some embodiments, the taper may be curved and / or stepped. The thickness difference between the thickest and thinnest areas of the diamond stage 1104 can be between 0.005 inches and 0.300 inches, while the total thickness of the diamond stage 1104 is between 0.050 inches and 0.350 inches.

[0101] Although the ridges or other protruding release features shown herein extend through the corners / cutting tips of a given cutting element, it should be understood that some embodiments of the cutting element may include recessed release features as an alternative to or addition to protruding release features. Such recessed release features can form a smaller thickness region of the diamond stage and can make the cutting tip more prominent to improve point load. Typically, recessed release features may be positioned between two or more protruding release features to create a deeper or more prominent valley between the protruding release features. Additionally, the presence of one or more recessed release features can further make the cutting tip more prominent and can improve the point load and drilling efficiency of the cutting element.

[0102] In some embodiments, instead of different release features such as ridges, grooves and the like, the cutting element may include an inclined surface that effectively imparts a forward tilt angle to the cutting surface. Figures 12A-13DA cutting element with a forward tilt angle is shown according to an embodiment of the present invention. For example, Figure 12A-12D A rectangular cutting element 1200 with a forward tilt angle is shown. The cutting element 1200 may be similar to the rectangular cutting element 400 and may include any of the features described with respect to the cutting element 400. For example, the cutting element 1200 may include a body formed by a base 1202 and a diamond stage 1204 coupled to the base 1202. The diamond stage 1204 may include a cutting tip 1222 configured to engage and cut formations during downhole operations. The cutting surface 1212 of the diamond stage 1204 may be tapered or otherwise inclined such that the diamond stage 1204 is thickest at the cutting tip 1222. For example, as shown, the diamond stage 1204 is inclined from its thinnest point near the corner of the diamond stage 1204 opposite to the cutting tip 1222 to its thickest point at the cutting tip 1222. This inclination may be linear as shown herein, or it may be curved and / or stepped as in some embodiments. The thickness difference between the thickest and thinnest areas of the diamond platform 1204 can be between 0.005 inches and 0.300 inches, with the total thickness of the diamond platform 1204 between 0.050 inches and 0.350 inches. When the cutting element 1200 is mounted in the recess of the downhole tool in the cutting position, such that the cutting tip 1222 protrudes beyond the top surface of the downhole tool's cutting edge, the increased thickness at the cutting tip 1222 imparts a tilt angle to the cutting element 1200. This tilt angle ensures that the cutting element 1200 is tilted forward in the drill bit rotation direction, such that the angle between the cutting face 1212 and the formation in front of the cutting face 1212 is greater than 90°. The tilt angle allows the cutting element 1200 to drill deeper into the cutting formation.

[0103] In some embodiments, the cutting element with a forward tilt angle can be double-sided. Figures 13A-13DA double-sided rectangular cutting element 1300 with a forward tilt angle is shown. Cutting element 1300 may be similar to rectangular cutting elements 400 and 1000 and may include any of the features described with respect to cutting elements 400 and 1000. For example, cutting element 1300 may include a body formed by a base 1302 and a diamond stage 1304 coupled to the base 1302. Diamond stage 1304 may include a cutting surface 1312 having two cutting tips 1322, both configured to engage and cut formations during downhole operations. The cutting tips 1322 may be positioned at opposite corners of diamond stage 1304 such that only one cutting tip 1322 is used at a given time to disrupt the formation, allowing cutting element 1300 to be rotated after use to expose different cutting tips 1322 after the first cutting tip 1322 has worn down. The cutting surface 1312 of the diamond stage 1304 may be tapered or otherwise sloped such that the diamond stage 1304 is thickest at the cutting tip 1322 of the diamond stage 1304. For example, as shown, the diamond stage 1304 slopes from its thinnest point near the centerline of the diamond stage 1304 (which extends through the corners of the diamond stage 1304 where no cutting tip 1322 is formed) to its thickest point at each cutting tip 1322. This slope may be linear as shown herein, or in some embodiments may be curved and / or stepped. The thickness difference between the thickest and thinnest regions of the diamond stage 1304 may be between 0.005 inches and 0.300 inches, wherein the total thickness of the diamond stage 1304 is between 0.050 inches and 0.350 inches. When the cutting element 1300 is mounted in the recess of the downhole tool in the cutting position, such that a cutting tip 1322 protrudes beyond the top surface of the downhole tool's cutting edge, the increased thickness at each cutting tip 1322 imparts a tilt angle to the cutting element 1300. The tilt angle ensures that the cutting element 1300 is tilted forward in the drill bit rotation direction, such that the angle between the cutting face 1322 and the formation in front of the cutting face 1312 is greater than 90°. The tilt angle allows the cutting element 1300 to drill deeper into the cutting formation.

[0104] although Figure 10A-12D A release feature formed on the cutting surface of a rectangular cutting element is shown; however, it should be understood that similar release features can be incorporated into cutting elements having other non-circular cross-sectional shapes. Furthermore, the cutting element can be formed with any number of release features. For example, in some embodiments, each cutting tip of a given cutting element may include a protruding feature. Release features can be different elements separated by regions with different diamond abutment thicknesses and / or can be continuous regions of other regions with thicknesses greater or less than the diamond abutment. It should be understood that protruding features are not limited to being located at the cutting tip of the cutting element, and regions of the diamond abutment not intended to serve as cutting tips may include protruding features.

[0105] As described above, the cutting element described herein may include a chamfered edge extending from the cutting surface of the diamond stage to the lateral surface of the diamond stage. This chamfered edge can increase the surface area of ​​the cutting tip and eliminate sharp angles that could lead to high force concentrations (which could prematurely damage the cutting element). In some embodiments, the chamfered edge may be uniform around the entire outer periphery of the cutting surface, wherein the angle and depth of the chamfered edge are consistent around the entire outer periphery of the cutting surface. In other embodiments, the angle and / or depth of the chamfered edge may vary along the outer periphery of the cutting surface. Figures 14A-14C An embodiment of a cutting element 1400 is shown, the cutting element including a chamfered edge 1416 extending from the cutting surface 1414 of the diamond stage 1404 to the lateral surface 1414 of the diamond stage 1404. (See also...) Figure 14A As shown, the chamfered edge 1416a is widest near the two corners and narrows towards the two opposite corners. Variations in width can be controlled by changing the depth of the chamfer (e.g., the distance from the cutting surface 1412 to the lateral surface 1414) and / or the angle of the chamfer. In some embodiments, the transition from one chamfer width to another can be achieved along the lateral surface 1414 and / or along the corners of the cutting surface 1412. The transition in width can be linear and / or arcuate. Figure 14B As shown, the chamfered edge 1416b is widest near the first pair of opposite corners and narrowest at the other pair of opposite corners. In the illustrated embodiment, the transition between the wide and narrow chamfered regions is linear. Figure 14C A similar chamfered edge 1416c is shown, in which the transition between the wide and narrow chamfered regions is arc-shaped, wherein the arc is concave relative to the cutting surface 1412c. In some embodiments, the wider region of the chamfered edge 1416 can serve as a cutting tip, while in other embodiments, the narrower region of the chamfered edge 1416 can serve as a cutting tip. In some embodiments, different cutting tips on a single cutting element 1400 can have chamfered edges 1416 with different geometries, allowing the cutting element 1400 to be oriented such that a particular cutting tip is in a cutting position to meet the needs of a particular downhole operation, thereby allowing a single cutting element 1400 to provide different cutting parameters.

[0106] In some embodiments, the width of the chamfered edge 1416 can be between approximately 0.005 inches and 0.040 inches, with the difference between the widest and narrowest areas typically between 0.005 inches and 0.035 inches, and more commonly between 0.010 inches and 0.025 inches. The angle of the chamfered edge 1416 relative to the cutting surface 1412 can be between 20 degrees and 60 degrees, though more commonly between 30 degrees and 50 degrees. The chamfered edge 1416 may extend at an angle through the cutting surface 1412 and / or the lateral surface 1414 to form a sharp corner, and / or may be formed with a radius to soften the corner. Typically, the chamfered edge 1416 is formed at least partially using laser grinding technology, which allows the chamfered edge 1416 to include a mixture of geometries.

[0107] In some embodiments, the angle of the chamfered edge relative to the cutting surface may vary along the periphery of the cutting surface. For example, the angle of the chamfered edge relative to the cutting surface at the cutting region of the cutting surface may be greater than the angle of the chamfered edge relative to the cutting surface at the middle region of the cutting surface. In other embodiments, the angle of the chamfered edge relative to the cutting surface at the cutting region of the cutting surface may be less than the angle of the chamfered edge relative to the cutting surface at the middle region of the cutting surface. In some embodiments, the depth of the chamfered edge may vary along the periphery of the cutting surface. For example, the depth of the chamfered edge at the cutting region of the cutting surface may be greater than the depth of the chamfered edge at the middle region of the cutting surface. In other embodiments, the depth of the chamfered edge at the cutting region of the cutting surface may be less than the depth of the chamfered edge at the middle region of the cutting surface.

[0108] As described above, each cutting element may include a substrate and a diamond stage connected to the substrate. The substrate may include an interface formed in the surface of the substrate facing the diamond stage. This interface may be formed by pressing, molding, and / or etching the substrate such that the interface protrudes from the top surface of the substrate along the direction of the diamond stage. The interface may substantially correspond to the peripheral shape of the top surface of the substrate and / or the peripheral shape of the diamond stage. For example, in a conventional cylindrical substrate, a cylindrical interface may protrude upward from the top surface of the substrate. Therefore, the diamond stage may include a corresponding (e.g., substantially the same size and shape) recess such that the substrate and the diamond stage can be connected via the insertion of the cylindrical interface into the recess of the diamond stage. In non-cylindrical cutting elements (e.g., those described above), the interface may be a non-planar interface (NPI) with a non-circular cross-section that may match the cross-sectional shape of the substrate and / or the diamond stage. In other words, the shape of the outer periphery of the non-planar interface may match the shape of the outer periphery of the topmost planar surface of the substrate and / or the outer periphery of the diamond stage. This allows the forces transmitted through the cutting part to be distributed more evenly at the interface between the diamond stage and the matrix and / or prevents the formation of weak points within the diamond stage.

[0109] Figure 15An embodiment of a non-cylindrical cutting element 1500 with a non-cylindrical, non-planar interface 1530 is shown. Cutting element 1500 may be similar to cutting elements 400-1400 described herein and may include any of the features described with respect to those cutting elements. Additionally, each of cutting elements 400-1400 may incorporate a non-planar interface, such as those described herein. Cutting element 1500 may include a base 1502 and a diamond stage 1504. Cutting element 1500 may have a generally rectangular cross-section, similar to cutting element 400. The non-planar interface 1530 may include an outer periphery whose shape substantially matches the outer periphery of the top surface 1515 of the diamond stage 1504, such that the spacing between the edge of the non-planar interface 1530 and the edge of the substrate 1502 and / or the diamond stage 1504 is substantially consistent around the entire periphery of the substrate 1502 and / or the diamond stage 1504 (e.g., within 20%, within 15%, within 10%, within 5%, within 3%, within 1%, or less). The top surface of the non-planar interface 1530 may be planar or non-planar. For example, as shown, the non-planar interface 1530 includes ridges 1532 and grooves 1534, wherein each ridge 1532 is identical in size and shape, and each groove 1534 is identical in size and shape. In other embodiments, the non-planar interface 1530 may include a lattice pattern, a honeycomb pattern, ridges, rings, etc., which allow a portion of the diamond stage to be pressed into the voids formed within the pattern. Additionally, in some embodiments, ridges, grooves, and / or other non-planar features may have different dimensions and / or shapes in the length and / or width of the non-planar interface 1530.

[0110] Figure 16Several views of one embodiment of a forming cutter 1600 are shown, the forming cutter having a non-planar interface 1630 with varying thickness over a surface region of the non-planar interface 1630. The cutter 1600 may be similar to the cutters 400-1500 described herein and may include any of the features described with respect to those cutters. The cutter 1600 may include a base 1602 and a diamond stage 1604, both having non-circular cross-sections on the top surface of the base 1602 and almost the entirety of the diamond stage 1604. The diamond stage 1604 may include release features, such as a protruding ridge 1620. As shown, the ridge 1620 may extend across the diameter of the diamond stage 1604, from a recess 1619 in the base 1602 to another recess 1619 on the opposite side of the base 1602, although other orientations are possible in various embodiments. Although only one release feature in the diamond stage 1604 is shown in the figure, the diamond stage 1604 may include any number of release features having various shapes and sizes. As shown, the thickness of the non-planar interface 1630 can vary depending on the thickness of the diamond stage 1604. For example, in the case where the diamond stage 1604 includes a protruding ridge 1620, the thickness of the non-planar interface 1630 may increase in the region corresponding to the protruding ridge 1620 (e.g., the region located below and supporting the protruding ridge). In some embodiments, the thickness variation of the non-planar interface 1630 in the region below the ridge 1620 may be the same as the protrusion distance of the ridge 1620, while in other embodiments, the protrusion distance may be greater than or less than the thickness variation of the non-planar interface 1630. Similarly, in the case where the diamond stage 1604 includes a recessed release feature, the thickness of the non-planar interface 1630 may decrease in the region corresponding to the recessed release feature (e.g., the region located below and supporting the recessed release feature). In some embodiments, the thickness variation of the non-planar interface 1630 in the region below the recessed release feature may be the same as the depth of the recessed release feature, while in other embodiments, the depth may be greater than or less than the thickness variation of the non-planar interface 1630.

[0111] As described above, each cutting element can be received within a recess formed within the cutting edge of a downhole tool (e.g., a drill bit or reamer). For non-cylindrical cutting elements, the corresponding recess can also have a non-cylindrical shape (i.e., not simply composed of a circular or partially circular cross-section). In particular, the size and shape of each recess can substantially match the size and shape of at least a portion of the cutting element inserted into that recess. This allows the non-cylindrical cutting element to be securely received within the cutting element recess, preventing rotation within the recess. The outer dimensions of the recess can be slightly larger than the outer dimensions of the cutting element, for example, between 0.01 inches and 0.025 inches larger. This provides sufficient clearance for the brazing material used to attach the cutting element to the walls defining the recess, while still limiting the ability of the cutting element to rotate within the recess. Inserting the cutting element into the recess thus allows the cutting element to be fully or substantially oriented in the correct position relative to the cutting edge. More specifically, due to the recess and the non-circular cross-section of the cutting element, inserting the cutting element into the insert can result in the cutting tip of the cutting element being at a desired angle and protruding beyond the top surface of the insert (e.g., in the cutting position), while the brazing gap is very small, requiring little or no alignment effort from the installer. Furthermore, for cutting elements with multiple discrete cutting tips, any number of cutting tips can be placed in the cutting position, allowing the cutting element to be removed from the recess, rotated, and then inserted again after a period of use, with different cutting tips in the cutting position, thereby extending the service life of the cutting element.

[0112] Although described as non-cylindrical or having a non-circular cross-section, it should be understood that the recesses described herein may not completely surround the lateral surfaces of a given workpiece. For example, a given recess may only surround between 40% and 95% of the length of the outer periphery of the workpiece, with the remainder of the workpiece exposed beyond the top surface of the insert with the recess formed. Therefore, as used herein, a cylindrical recess or a recess with a circular cross-section refers to a recess in which, for more than 25% of the recess's length, the recess's cross-section is defined by a single sidewall with a constant radius (a portion of the circle may be missing because the recess may open at the top surface of the insert). Conversely, a non-cylindrical recess or a recess with a non-circular cross-section refers to a recess in which at least 10% of the non-circular cross-section is defined by one or more sidewalls having varying radii, one or more sidewalls with curvature not concentric with the central axis of the recess, and / or one or more sidewalls including one or more linear or convex features, wherein the non-circular cross-section extends at least the foremost 10%, 20%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, or more of the length of the recess, or possibly encompasses the entire length. This allows the leading edge of the recess and the corresponding leading edge of the cutting element to be indexed and positioned relative to the recess and the insert in the correct orientation. Embodiments with non-circular cross-sections extending all or most of the length of the cutting insert recess can be beneficial for improving drilling efficiency because the corresponding cutting insert has a smaller volume of matrix extending beyond the top surface of the blade and therefore provides less rotational resistance when engaging with the formation than conventional cylindrical cutting inserts.

[0113] Furthermore, when a cutting recess is referred to as having a specific cross-sectional shape, it means that the cutting recess is created as a gap formed in the insert by a portion of the described shape, such that cutting parts with the same cross-sectional dimensions and shape can be fitted into the recess without modification. For example, if the recess is described as having a rectangular cross-section, the recess may define only 40% to 95% of the rectangular cross-section and therefore may appear more like a triangle, pentagon, or other non-rectangular shape. However, rectangular cutting parts can be inserted into the recess, such that the discrete cutting tips of the cutting parts protrude beyond the top surface of the insert.

[0114] Non-cylindrical recesses can be manufactured into drill bits and / or reamers in a non-cylindrical form, or existing recesses (e.g., cylindrical or different non-cylindrical shapes) can be modified into non-cylindrical recesses. For example, one or more shims can be inserted into an existing recess, making the existing recess non-cylindrical. The non-cylindrical recess can then receive a corresponding non-cylindrical cutting element, such as those described above. In some embodiments, each shim can be inserted into the recess and then brazed to the corresponding cutting element. In other embodiments, each shim can be brazed, welded, or otherwise attached to the existing recess before the cutting element is inserted.

[0115] Figure 17 A drill bit 1700 without any cutting elements is shown. Drill bit 1700 may be similar to drill bits 100 and 200 and may include any features described with respect to drill bits 100 and 200. For example, drill bit 1700 may include a drill bit body 1704 designed to rotate about a central drill bit axis 1702. Drill bit body 1704 may include one or more protruding cutting edges 1710 extending from a face of drill bit body 1704. In some embodiments, the cutting edges 1710 extend radially along the drill bit face and are circumferentially spaced structures extending along the front end or formation junction of drill bit body 1704. Each cutting edge 1710 may extend generally radially outward to the periphery of drill bit body 1704. For example, the cutting edge 1710 may extend generally upward from a conical region near the longitudinal axis or central axis 1702 of the drill bit to the gauge region or maximum drill bit diameter of the drill bit. The channels formed between adjacent blades can create chip removal channels, which provide a path for drilling fluid and cuttings to be carried upward along the wellbore. As the drill bit 1700 rotates within the wellbore via the drill string, drilling fluid can be pumped downward along the drill string, through the internal fluid chambers and fluid passages within the drill bit body 1704 of the drill bit 1700, and exit from the drill bit 1700 through nozzle 1717.

[0116] Each blade 1710 may define a plurality of cutting recesses 1720, wherein each cutting recess is configured to receive a cutting element, such as cutting elements 112, 212-224, 316, and 400-1600. Some or all of the cutting recesses 1720 may include a non-circular cross-section. For example, a cutting recess 1720a may have a cross-section that is rectangular, triangular, pentagonal, stadium-shaped, and / or other non-circular shapes. Each cutting recess 1720a may be configured to receive a non-cylindrical cutting element, such as cutting elements 400-1600 as described herein. For example, each cutting recess 1720a may have a generally rectangular cross-section, such as having at least two orthogonal straight sides and rounded corners connecting these two orthogonal straight sides. In some embodiments, one or more additional corners and / or straight sides may be included, for example, in cases where a given cutting recess 1720a surrounds more than 50% of the circumference of the corresponding cutting element. Some or all of the recesses may surround different amounts of the cutting element. In some embodiments, the width of each rounded corner, measured from the central axis of the cut recess, can be between 5 degrees and 45 degrees.

[0117] In some embodiments, the drill bit 1700 may further include one or more rows of spare cutting recesses 1722 disposed on one or more cutting inserts 1710. For example, some cutting inserts 1710 may include two rows of cutting recesses 1720 (and subsequent cutting elements), wherein one row of cutting recesses is substantially located behind a first row of main cutting recesses 1720 that extends through the leading edge of the respective cutting insert 1710. In some embodiments, the spare cutting recesses 1722 may be located at the same radial position as the corresponding cutting recesses 1720, while in other embodiments, the spare cutting recesses 1722 may be located at a different radial position from the main cutting recesses 1720.

[0118] In some embodiments, the drill bit 1700 may include a plurality of conventional cylindrical cutting recesses 1720b, which may be configured to receive conventional cylindrical cutting elements. For example, as shown, the cutting recesses 1720b in the nose region of the drill bit 1700 include cylindrical cutting recesses 1720b, while non-cylindrical cutting recesses 1720a are disposed radially outside the cylindrical cutting recesses 1720b. It should be understood that other variations are also possible, and in some embodiments, the cylindrical cutting recesses 1720b may be located at other radial locations and / or omitted entirely.

[0119] In some embodiments, each blade 1710 may include one or more knuckles 1730 that project from the top surface of the blade 1710 and align with a corresponding cutting recess 1720 or 1722. Each knuckle 1730 may support a portion of the base of a cutting element seated within the corresponding cutting recess 1720 or 1722. In some embodiments, the size and shape of each knuckle 1730 may correspond to the size and shape of the portion of the cutting element that extends above the top surface of the blade 1710 on which the cutting element is mounted. For example, if the portion of a rectangular cutting element that protrudes above the top surface of the blade 1710 is generally triangular, the front surface of the knuckle 1730 may have a generally triangular shape. Thus, the base of each cutting recess 1720 or 1722 and the front of the corresponding knuckle 1730 may extend together behind the complete base of the cutting element received within the cutting recess 1720 or 1722, and may provide additional support to the cutting element against the direction of rotation during downhole operations. In some embodiments, the cross-sectional dimensions and shape of each finger portion 1730 may be substantially the same as and / or smaller than the cross-sectional area of ​​the portion of the cutting element that protrudes beyond the top surface of the blade 1710. This design ensures that the finger portion 1730 does not engage with the cutting layer and can help reduce wear on the finger portion 1730. The top surface of each finger portion 1730 may taper downwards toward the top surface of the blade 1710 in a direction away from the cutting element recesses 1720 or 1722. In other embodiments, the transition from the front surface of the finger portion 1730 to the top surface of the blade 1710 may be stepped. The cross-sectional shape of each finger portion 1730 may remain constant throughout the transition, or it may vary.

[0120] Although rectangular and cylindrical cutting recesses are shown, it should be understood that any arrangement of cutting recesses of different shapes can be combined into a single drill bit. For example, each cutting shape can create a cutting tip with different cutting characteristics. The cutting recesses and cutting elements of the drill bit can be selected to create a specific cutting profile that provides a given performance result.

[0121] Figures 18A-18C A non-cylindrical cutting recess in which a non-cylindrical cutting element is inserted is shown, illustrating possible cutting locations for non-cylindrical cutting elements. The cutting recess 1800 can represent a cutting recess formed on the cutting edge of a downhole tool, such as drill bits 100, 200, and 1700, and a reamer 300. For example, Figure 18AA generally rectangular cutting recess 1800a and a generally rectangular cutting element 1802a are shown. Cutting element 1802a may be similar to cutting element 400 and may include four linear lateral surfaces arranged in two pairs of parallel surfaces and connected by four corners, wherein the two pairs of linear lateral surfaces are orthogonal to each other to form a generally rectangular cross-section. Each corner of cutting element 1802a may form a discrete cutting tip that may protrude above the top surface of cutting recess 1800a and the insert forming the cutting recess 1800a therein. In some embodiments, the dimensions of cutting recess 1800a may be designed such that only two orthogonal linear surfaces and a single corner are provided. In other embodiments, two or three corners may be included, possibly with one or two additional linear surfaces in multiple portions. In cases where more than 50% of the periphery of the cutting element 1802a is restricted, the cutting element 1802a can be loaded from the front into the recess 1800a. This helps to hold the cutting element 1802a within the recess 1800a during downhole operations, since the only direction in which the cutting element 1802a can be removed is along the rotational direction of the downhole tool. In some embodiments, the finger portion 1804a may be positioned behind the cutting element recess 1800a. The finger portion 1804a may have a generally triangular shape such that the base of the cutting element recess 1802a and the front of the finger portion 1804a can extend together behind the complete base of the cutting element 1802a to provide additional support for the cutting element 1802a along the rotational direction during downhole operations. Due to the size and shape of the cutting recess 1800a and the cutting element 1802a, the cutting element 1802a can be inserted into the cutting recess 1800a in four different orientations, wherein each orientation aligns a different cutting tip of the cutting element 1802a in the cutting position. In some embodiments, each cutting tip may be identical, while in other embodiments, one or more cutting tips may include different release features and / or chamfered edges as described herein. This allows a single cutting element 1802a to be inserted along different orientations to provide consistent results (when the cutting tips are identical) or customized results (when the cutting tips have different characteristics), and also allows the cutting element 1802a to be reused even after one cutting tip has been damaged.

[0122] Figure 18BA generally triangular cutting recess 1800b and a generally triangular cutting element 1802b are shown. Cutting element 1802b can be similar to cutting element 500 and can include three linear lateral surfaces arranged at 120-degree angles to each other and connected by three corners to form a generally rectangular cross-section. Each corner of cutting element 1802b can form a discrete cutting tip that protrudes above the top surface of cutting recess 1800b and the insert forming the recess therein. The dimensions of cutting recess 1800b can be designed to include multiple portions comprising a linear bottom surface, two corners, and two linear sidewalls at 60 degrees relative to the linear bottom surface (in opposite directions) and providing a single corner. Such a design helps to lock cutting element 1802b into cutting recess 1800b. For example, the cutting element 1802b can be loaded into the recess 1800b from the front, which helps to hold the cutting element 1802b within the recess 1800b during downhole operations. In some embodiments, a finger portion 1804b may be disposed behind the recess 1800b. The finger portion 1804b may have a generally triangular shape such that the base of the cutting element recess 1802b and the front of the finger portion 1804b can extend together behind the complete base of the cutting element 1802b to provide additional support for the cutting element 1802b along the direction of rotation during downhole operations. Due to the size and shape of the cutting element recess 1800b and the cutting element 1802b, the cutting element 1802b can be inserted into the cutting element recess 1800b along three orientations, wherein each orientation causes a different cutting tip of the cutting element 1802b to be aligned in the cutting position. In some embodiments, each cutting tip may be identical, while in other embodiments, one or more cutting tips may include the different release features and / or chamfered edges described herein. This allows a single cutting element 1802b to be inserted along different orientations to provide consistent results (when the cutting tip is the same) or customized results (when the cutting tip has different characteristics), and also allows the cutting element 1802b to be reused even after a cutting tip has been damaged.

[0123] Figure 18CA stadium-shaped cutting recess 1800c and a stadium-shaped cutting element 1802c are shown. The cutting element 1802c may be similar to the cutting element 700 and may include two parallel linear lateral surfaces connected by two rounded ends. Each rounded end of the cutting element 1802c may form a discrete cutting tip that protrudes above the top surface of the cutting recess 1800c and the insert forming the recess therein. In some embodiments, the dimensions of the cutting recess 1800c may be designed such that only two parallel linear lateral surfaces and a single arcuate bottom surface are provided. In various embodiments, the depth of the cutting recess 1800c may be between 25% and 75% of the length of the cutting element 1802c. In some embodiments, a finger portion 1804c may be provided rearward of the cutting recess 1800c. The knuckle portion 1804c may have a generally semi-sports stadium shape, such that the base of the cutting recess 1802c and the front of the knuckle portion 1804c can extend together behind the complete base of the cutting element 1802c to provide additional support for the cutting element 1802c along the direction of rotation during downhole operations. Due to the size and shape of the cutting recess 1800c and the cutting element 1802c, the cutting element 1802c can be inserted into the cutting recess 1800c along two different orientations, wherein each orientation aligns a different cutting tip of the cutting element 1802c in the cutting position. In some embodiments, each cutting tip may be identical, while in other embodiments, one or more cutting tips may include different release features and / or chamfered edges as described herein. This allows a single cutting element 1802c to be inserted along different orientations to provide consistent results (when the cutting tips are identical) or customized results (when the cutting tips have different characteristics), and also allows the cutting element 1802c to be reused even after one cutting tip has been damaged.

[0124] In some embodiments, a cylindrical or substantially cylindrical cutting recess may be formed within the cutting blade of a downhole tool, and the cylindrical or substantially cylindrical cutting recess may then be modified to be non-cylindrical. Figure 19-24 The invention illustrates a technique for modifying cylindrical or substantially cylindrical cutting recesses into non-cylindrical cutting recesses. Figure 19A cutting recess 1902 formed in a cutting insert 1900 of a downhole tool is shown, wherein the cutting recess 1902 has a generally circular cross-section. According to some embodiments, the sidewalls 1904 of the cutting recess 1902 define a keyway 1980. The sidewalls 1904 and / or the base 1906 of the cutting recess 1902 may at least partially correspond to the cross-sectional shape of a non-cylindrical cutting element (such as those described herein). For example, the base 1906 may extend upward beyond the top surface of the downhole tool cutting insert and form a finger portion 1930, such as regarding... Figure 17 And those described in Figure 18. As just one example, for a rectangular cutting part, the base 1906 and the finger portion 1930 can together form a generally rectangular shape. As shown, the base 1906 and the finger portion 1930 together form a teardrop shape, wherein the finger portion 1930 has a generally triangular cross-section corresponding to the portion of the rectangular cutting part that protrudes above the top surface of the insert. The finger portion 1930 can provide additional support for the cutting part and can also serve as a reference edge 1920, which can be used to indicate a predetermined orientation of the cutting part. Prior to modification, the cutting part recess 1902 could be configured to receive a cylindrical cutting part with a single scribe point. The finger portion 1930 and the reference edge 1920 can indicate a preferred orientation of the scribe point. Therefore, the finger portion 1930 and the reference edge 1920 can indicate a predetermined orientation of a non-cylindrical cutting part with a scribe point.

[0125] The sidewall 1904 of the cutting recess 1902 may include a keyway 1908. The keyway 1908 may be formed into the cutting recess 1902 during downhole tool manufacturing, or it may be formed later (e.g., by drilling the keyway 1908 into the cutting recess 1902). The keyway 1908 may be concave (including generally rounded grooves) and / or may be angled. As used herein, angled can refer to polygons, triangles, other shapes with straight sides, etc. The keyway 1908 may be substantially symmetrical or may be asymmetrical. Although only one keyway 1908 is shown, the cutting recess 1902 may include any number of keyways 1908.

[0126] Figure 20A keyed gasket 2000 according to some embodiments is shown. The keyed gasket 2000 may include a protrusion 2002, a gasket body 2006 having an arcuate outer surface 2012, a support surface 2004, a first end 2008, and a second end 2010. The keyed gasket 2000 may be made of steel, tungsten carbide, bronze, brass, Inconel, composite materials, ceramics, or any other suitable material. As described above, the protrusion 2002 may be substantially cylindrical and / or include angled features. The protrusion 2002 may extend from the first end 2008 to the second end 2010, or may only extend a portion of the distance between the first end 2008 and the second end 2010. The protrusion 2002 may be configured to substantially fill a recess in a keyway (e.g., keyway 1908). For example, after the protrusion 2002 is located in the keyway 1908, space may exist such that brazing material can be provided to secure the protrusion 2002 to the keyway 1908. In some embodiments, the protrusion 2002 may substantially fill the width of the groove of the keyway, but not the length of the groove of the keyway.

[0127] The support surface 2004 can be configured to change the shape of the cutting recess (e.g., cutting recess 1902) to receive a non-cylindrical cutting part. For example, as Figure 21 As shown, the support surface 2004 can be substantially planar. When inserted into the cutting recess 1902, the support surface 2004 can thus change the shape of the cutting recess 1902 to include sidewalls that are at least partially planar. Furthermore, the support surface 2004 can also correspond to the shape of at least one lateral surface of a non-cylindrical cutting element. For example, the non-cylindrical cutting element may include a planar surface that at least partially matches the support surface 2004. When the non-cylindrical cutting element is inserted into the hollow recess, the support surface 2004 can at least partially orient the non-cylindrical cutting element within the hollow recess according to a predetermined orientation.

[0128] Although the support surface 2004 is shown as substantially planar, it may include any number of recesses and / or protrusions. Furthermore, the keyed gasket 2000 may have a varying thickness, for example, one end being thicker than the other. For instance, the keyed gasket 2000 may be thicker at the second end 2010. Therefore, the support surface 2004 may be inclined at a first angle between the first end 2006 and the second end 2010. Alternatively, the second end 2010 may be thicker than the first end 2008, causing the support surface 2004 to be inclined at a different angle. Additionally, the support surface 2004 may be curved. For example, although the cutting recess 1902 may include a keyway 1908, a cylindrical cutting element may be inserted into the cutting recess 1902. The support surface 2004 may then substantially correspond to the sidewall of the cutting recess 1902, allowing the cylindrical cutting element to be received and the keyway 1908 to be substantially filled. Those skilled in the art will recognize many different possibilities and configurations.

[0129] Figure 21 A keyless gasket 2100 according to certain embodiments is shown. The keyless gasket may include a recessed surface 2102, a support surface 2104, a first end 2108, and a second end 2110. The keyless gasket 2100 may be made of steel, tungsten carbide, or any other suitable metal, ceramic, composite material, or other material. The recessed surface 2102 may be configured to correspond to the sidewall of a hollow recess (e.g., a cutting recess 1902). The recessed surface 2102 may be substantially rounded and / or may be angled or planar. Similarly, the support surface 2104 may be configured to correspond to the surface of a cutting element (e.g., a non-cylindrical cutting element). The support surface 2104 may include any number of protrusions and / or grooves such that the support surface 2104 mates with the surface of the cutting element. Similar to the keyed gasket 2000, the non-keyed gasket 2100 may be thicker at one end or the other, thereby forming an angle or ramp between the first end 2108 and the second end 2110. The support surface 2104 may also be curved, as described above with respect to the keyed gasket 2000.

[0130] When inserted into the hollow recess, the non-keyed shim 2100 can at least partially alter the shape of the cutting recess 1902, allowing it to receive a non-cylindrical cutting part. For example, a non-cylindrical cutting part can be inserted into the substantially cylindrical hollow recess. Therefore, a space can be defined between the non-cylindrical cutting part and the sidewalls of the hollow recess. The non-keyed shim 2100 can be inserted into this space, substantially filling it.

[0131] Figure 22A portion of a blade 1900 with a keyed washer 2000 and a non-keyed washer 2100, according to certain embodiments, is shown. (As described above regarding...) Figure 19 The cutting recess 1902 can initially be manufactured to receive a cylindrical cutting part. Therefore, the sidewall 1904 can be cylindrical. A keyed shim 2000 can be inserted into the cutting recess 1902, such that the protrusion 2002 substantially fills the keyway 1908. Similarly, a non-keyed shim 2100 can also be inserted into the cutting recess 1902. Both the support surface 2004 and the support surface 2104 can at least partially orient a non-cylindrical cutting part within the hollow recess 1902. For example, the non-cylindrical cutting part can be a rectangular cutting part. The support surface 2004, the support surface 2104, the knuckle portion 1930, and the reference edge 1920 can help orient (or index) the non-cylindrical cutting part such that the corners or cutting tips of the rectangular cutting part are aligned with the reference edge 1920 according to a predetermined orientation.

[0132] Keyed shims 2000 and / or unkeyed shims 2100 can be attached to the cutting recess 1902 and / or the non-cylindrical recess during brazing. For example, brazing can be initiated to attach the non-cylindrical cutting part to the cutting recess 1902. At some point during brazing, one or both of the keyed shims 2000 and unkeyed shims 2100 can be inserted into the cutting recess 1902 to at least partially align the non-cylindrical cutting part according to a predetermined orientation. Keyed shims 2000 and unkeyed shims 2100 can also be brazed such that they are attached to the cutting recess 1902 and / or the non-cylindrical cutting part, and that the non-cylindrical cutting part is attached to and / or secured within the cutting recess 1902. Although Figure 22 Only one keyed shim 2000 and one unkeyed shim 2100 are shown, but any number of shims (e.g., 2, 3, 4, 5, etc.) can be present, including both keyed and unkeyed shims. Although each shim is shown to include a single support surface, it should be understood that a single shim can include multiple different support surfaces, which may be angled relative to each other. For example, a single shim can be used to provide two lateral surfaces to support corresponding lateral surfaces of a rectangular (or other non-cylindrical) cut part.

[0133] In other embodiments, the keyed gasket 2000 and / or the non-keyed gasket 2100 may be attached to the cutting recess 1902 by welding (e.g., spot welding), chemical bonding, or any other suitable method. The keyed gasket 2000 and / or the non-keyed gasket 2100 may be inserted and attached to the cutting recess 1902 at a point before insertion into the non-cylindrical cutting part, or at a point after insertion into the non-cylindrical cutting part.

[0134] Figure 23 A spacer 2300 with a keyless shim 2100 according to certain embodiments is shown. The spacer 2300 can be configured to align a non-cylindrical cutting element at least partially in a predetermined orientation. The spacer 2300 and / or the keyless shim 2100 can be made of steel, bronze, brass, tungsten carbide, inconel, ceramic, composite material, or any other suitable material. In some embodiments, the spacer 2300 can be configured such that the hollow recess of the drilling tool can receive non-cylindrical cutting elements of various lengths. Additionally or alternatively, the spacer 2300 can also be configured to support the non-cylindrical cutting element such that the non-cylindrical cutting element extends beyond the hollow recess of the drilling tool (e.g., Figure 19 (Dent 1902 in the cutting part).

[0135] Although the spacer 2300 is shown as substantially flat, the spacer 2300 can be configured to tilt the non-cylindrical cut member within the hollow recess. For example, the thickness of the spacer 2300 can be greater on the back side of the spacer 2300 (e.g., where the unkeyed spacer 2100 is attached). Therefore, when the non-cylindrical cut member is placed on the spacer 2300 within the cut member recess 1902, the non-cylindrical cut member can be angled away from the unkeyed spacer 2100. Furthermore, although the spacer 2300 is shown attached to the unkeyed spacer 2100, any number of keyed and / or unkeyed spacers can be present. For example, the spacer 2300 can be attached to a keyed spacer but not to the unkeyed spacer 2100. In other examples, two unkeyed spacers and one keyed spacer can be present. Those skilled in the art will appreciate a variety of different possibilities and configurations. In some embodiments, the spacer 2300 and the unkeyed spacer 2100 can be a single integral component.

[0136] Figure 24 A blade 1900 with a spacer 2300 and two non-keyed spacers 2100a-2100b is shown according to some embodiments. Figure 24 As shown, the recess 1902 of the machined part may not include a keyway (e.g. Figure 19 As shown above). Figure 19The cutting recess 1902 can initially be manufactured to receive a cylindrical cutting part. Therefore, the sidewall 1904 can be cylindrical. Non-keyed gaskets 2100a-2100b can be inserted into the cutting recess 1902. Surfaces 2104a and 2104b can at least partially orient the non-cylindrical cutting part within the cutting recess 1902. For example, the non-cylindrical cutting part can be a rectangular cutting part, which can be oriented such that corners or cutting tips face upwards along a predetermined orientation surface based on the positioning of surfaces 2104a and 2104b and the reference edge 1920.

[0137] Furthermore, the spacer 2300 can also be inserted in a predetermined orientation. The spacer 2300 can be inserted in a predetermined orientation prior to a brazing process for attaching a non-cylindrical cut part in the predetermined orientation. The spacer 2300 can be attached before or during the brazing process. In some embodiments, the spacer 2300 can be attached to the predetermined orientation via welding (e.g., spot welding), chemical bonding, or any other suitable method.

[0138] During the brazing process, the unbonded spacers 2100a-2100b can be attached to a predetermined orientation and / or to a non-cylindrical cutting element. For example, the brazing process can be initiated to attach the non-cylindrical cutting element to the predetermined orientation. At some point during the brazing process, one or both unbonded spacers 2100a-2100b can be inserted in the predetermined orientation to at least partially align the non-cylindrical cutting element in the predetermined orientation. The unbonded spacers 2100a-2100b can then be brazed such that they are attached to the predetermined orientation and / or to the non-cylindrical cutting element, and that the non-cylindrical cutting element is attached to and / or secured within the predetermined orientation. In some embodiments, the unbonded spacers 2100a-2100b can be attached to the predetermined orientation via welding (e.g., spot welding), chemical bonding, or any other suitable method.

[0139] Although cutter recesses and cutters are shown in rectangular, triangular, and stadium shapes, it should be understood that other shapes of cutters and cutter recesses may be used in various embodiments. In some embodiments, the cutter may include a diamond stage with a non-cylindrical outer periphery configured to rotate about the central axis of the cutter within a corresponding cutter recess at an angle between 60 and 300 degrees to expose a new cutting edge or cutting tip with similar point load capacity, while maintaining a brazing gap thickness of 0.015 inches or less on more than 85% of the brazable surface area of ​​a conventional cylindrical cutter of similar size (e.g., a cylindrical cutter with the same maximum outer diameter or other maximum lateral dimension as the non-cylindrical cutter). In other words, the cross-sectional area of ​​the new cutting tip may be smaller than the cross-sectional area of ​​the corresponding portion of a conventional cylindrical cutter that protrudes beyond the top surface of the insert, thereby allowing for a higher force concentration on the exposed cutting tip compared to the case of a conventional cylindrical cutter. For example, a rectangular cutting element can be rotated relative to the cutting element recess / insert in 90-degree increments to expose a new cutting tip (e.g., to position the new cutting tip in the cutting position). Similarly, a triangular cutting element can be rotated relative to the cutting element recess / insert in 120-degree increments to expose a new cutting tip, a stadium-shaped cutting element can be rotated relative to the cutting element recess / insert in 180-degree increments to expose a new cutting tip, a pentagonal cutting element can be rotated relative to the cutting element recess / insert in 72-degree increments to expose a new cutting tip, and a hexagonal cutting element can be rotated relative to the cutting element recess / insert in 60-degree increments to expose a new cutting tip. Other variations are also possible. The shape and orientation of both the cutting element recess and the corresponding cutting element can be chosen such that when the cutting element is inserted into the cutting element recess, it is oriented such that the cutting tip protrudes beyond the top surface of the corresponding insert among a plurality of inserts. In other words, the cutting tip protruding above the top surface of the cutting element recess / insert is in the cutting position. The location and orientation of each cutting recess within a given insert of a downhole tool can be selected to control various parameters of the cutting element. For example, the location of the cutting recess can control the depth of cut, as well as the magnitude of the rake, backslope, and / or yaw angles of the cutting element, which can affect the effectiveness of the downhole tool, as will be described in more detail below.

[0140] Compared to using cylindrical cutting parts, using non-cylindrical cutting parts and cutting part recesses allows for a greater number of cutting parts to be placed on a given insert. For example, the cutting tip of a non-cylindrical cutting part can be more pronounced than the constant radius of a cylindrical cutting part. Furthermore, the constant radius of a cylindrical cutting part requires a considerable amount of space within the insert to form each cutting part recess. In contrast, some non-cylindrical cutting part shapes can provide a sufficiently large cutting tip while requiring less space within the insert, allowing for a greater number of cutting parts and thus a larger cutting surface area. This is just one example. Figure 25 A portion of a cutting insert 2500 is shown, having a plurality of generally stadium-shaped cutting elements 2502 received within a cutting recess of the cutting insert 2500. The cutting elements 2502 can be similar to cutting element 700 and can include any features described with respect to cutting element 700. Due to the reduced lateral dimensions of the cutting elements 2502 (e.g., the width between opposite faces of the central rectangular region), the required distance between adjacent cutting elements 2502 is reduced, allowing for a greater number of cutting elements 2502 to be included on the cutting insert 2500. For example, the circular dashed line 2504 indicates the dimensions of a comparable cylindrical cutting element. As shown, the dashed lines 2504 of adjacent cutting elements overlap, which would mean that if cylindrical cutting elements were used, the cutting elements would need to be spaced further apart, and fewer cutting elements would be included. By increasing the number of cutting elements on the cutting insert, the size of the drill bit profile can be reduced while still allowing the drill bit to break the same amount of material in a given rotation. Additionally, the drill speed can be increased. In some embodiments, a greater number of cutting elements per blade can enable a reduction in the number of blades on the drill bit, which can facilitate better flushing of drilling fluid.

[0141] Figure 26 This is a flowchart illustrating the operation of a method 2600 for bonding a cutting element to a downhole tool according to some embodiments of the present invention. Method 2600 can be used to secure a non-cylindrical cutting element (e.g., cutting elements 400-1600) to a corresponding non-cylindrical cutting element recess (e.g., cutting element recesses 1720, 1722, 1600, and 1902). Method 2600 can begin with operation 2602, in which a cutting element having a non-cylindrical cross-section is inserted into a non-cylindrical recess formed in the downhole tool. A small gap, for example, between about 0.010 inches and about 0.025 inches, can be formed between the outer surface of the cutting element and the wall defining the recess. This gap can provide a volume for receiving a metallic material (e.g., a brazing alloy) used to bond the cutting element to the wall of the recess. In some embodiments, the recess can be preheated before insertion of the cutting element, for example by using a welding torch, to heat the recess to a temperature sufficiently high to receive and bond to the brazing material.

[0142] In operation 2604, a metallic material may be provided into the gap. For example, a brazing alloy may be melted and delivered into the gap such that the brazing alloy is positioned between all or substantially all of the walls defining the recess and adjacent portions of the cutting element, including the base of the cutting element / recess and at least a portion of one or more lateral sidewalls or other surfaces of the cutting element / recess. A flux compound may be supplied to the brazed joint before, during, and / or after the application of the brazing alloy. The flux compound helps prevent oxide formation at the brazed joint and can help promote a higher quality brazed joint by allowing the brazing alloy to flow more freely within the gap between the cutting element and the recess. In operation 2606, the cutting element may be fixed within the recess, for example, by allowing the brazing alloy to cool and bond to both the cutting element and the recess, thereby connecting the cutting element to the downhole tool.

[0143] Figure 27This is a flowchart illustrating the operation of a method 2700 for manufacturing downhole tools according to some embodiments of the present invention. Method 2700 can be used to manufacture downhole tools (e.g., drill bits 100, 200, 1500, reamers 300, and / or other downhole tools) including non-cylindrical cutting parts (e.g., cutting parts 400-1600). In particular, method 2700 can be used to manufacture cast matrix downhole tools. Method 2700 can begin with operation 2702, in which a mold for forming the body of the downhole tool is formed. The mold can be formed from a rigid, machinable, and heat-resistant material, such as (but not limited to) graphite or other carbon-based materials. For example, graphite rods can be cut into pucks slightly larger than the size of the final mold. Forming the mold can include, for example, machining the mold using a computer numerical control (CNC) milling machine and / or other machining tools. The mold can create voids representing features of the body of the downhole tool, including faces and multiple cutting edges. Positioning features or grooves for the replacement piece can be machined onto each cutting edge to represent the final cutting edge position on the downhole tool. At least some of these positioning features may have a non-cylindrical cross-section or include one or more sidewalls that do not contain a single arc with a constant radius. In some embodiments, such positioning for a non-cylindrical replacement piece may include one or more indexing features, such as ridges, grooves, visible markings, and / or other features, that allow the replacement piece to be properly aligned within the recess. Additional positioning features may also be provided for other features of the downhole tool, such as nozzles. Different positioning features may have different sizes and shapes. For example, positioning features for a front-loaded cutting edge recess may have different sizes and shapes than those for a top-loaded cutting edge recess, which may be necessary when the cutting edge meets in a mid- or double-row position. The lack of clearance in front of the cutting edge recess requires the cutting edge to be loaded into the recess from the top of the cutting edge rather than from the front. The size, shape, and orientation of each cutting part positioning feature can define the final cutting part recess and the final shape, size, and orientation of the cutting part (e.g., rake angle, back rake angle, side rake angle, cutting tip rotation, etc.).

[0144] Once the mold is formed, multiple replacement parts (including cutting recess replacement parts) can be inserted into the mold, for example, inserted into the positioning feature in operation 2704. Each replacement part can be formed from a material suitable for casting metals, such as graphite and / or resin sand. Each replacement part can be oriented in the corresponding positioning feature to ensure that the final cutting recess and cutting part are correctly positioned on the downhole tool's blade. In some embodiments, this alignment can be done manually. For example, visual indicators, such as notches, grooves, or other indexing features, can be formed in the replacement parts and / or positioning features to help installers correctly insert and align the replacement parts within the corresponding positioning features. In other embodiments, the positioning features and corresponding replacement parts can have non-cylindrical cross-sections or other geometries that force the replacement parts to be correctly oriented within the positioning features. In some embodiments, a ridge can be formed in the replacement part or positioning feature, and a corresponding groove can be formed in another component. Inserting the ridge into the groove allows the replacement part to be aligned within the positioning feature. In some embodiments, a concave surface can be formed in the replacement part or positioning feature, and a corresponding convex surface can be formed in another component. Inserting the convex surface into the concave surface aligns the replacement member within the positioning feature. In some embodiments, both the positioning feature and the cutting element may define slots. A key may be simultaneously inserted into both slots to align the replacement member within the positioning feature. In some embodiments, a hole may be drilled through the chip removal groove in the hemispherical gap, a hole may be drilled in / through the replacement member, and a pin may be inserted through both holes to orient the replacement member within the positioning feature. In some embodiments, a shallow hole may be drilled in the groove of the positioning feature at an angle not parallel to the axis of rotation of the replacement member. A corresponding hole may be drilled in or through the replacement member, and a pin may be inserted into the holes in both the die and the replacement member to align the replacement member within the positioning feature. Other techniques for aligning the replacement member within the positioning feature are also possible in various embodiments. The replacement member may also include a replacement member for a nozzle and a central bore that can be used to deliver drilling fluid to the nozzle. Various replacement members may be adhered to the positioning feature using adhesive materials.

[0145] Once the replacement part has been secured to the mold, the head steel billet (e.g., a billet for later welding of the drill shank, drill bit loader surface, and connector for attaching the drill bit to the drill string) can be partially positioned within the mold. At this point, the mold can be filled in operation 2706 with a particulate carbide material and a binder material. For example, the carbide material may include tungsten carbide (or other hard metals, such as titanium carbide and / or tantalum carbide) powder. In some embodiments, the tungsten carbide powder may comprise between about 80% and about 95% tungsten, between about 3% and about 15% carbon, and may include trace elements of iron, nickel, molybdenum, titanium, tantalum, and / or niobium, but other formulations are possible in various embodiments. The binder material may be provided as several metal pellets or other blocks with dimensions generally on the order of 0.5 square inches to 2.0 square inches, but other sizes may be used in various embodiments. In some embodiments, the binder material may include copper, nickel, silver, and / or alloys thereof, such as in the form of a copper-based alloy binder. For example, the binder material may include about 40% to about 60% copper, about 20% to about 30% manganese, about 10% to about 20% nickel, and may include trace elements such as zinc, iron, lead, silicon and / or tin.

[0146] In operation 2708, the mold can be placed in a furnace, exposing the filled mold to a temperature between approximately 1500°F and 2500°F for a period of approximately 2 to 5 hours. Heating melts the binder material and allows it to flow downwards into the tungsten carbide powder. Upon cooling, the tungsten carbide powder will form the body of the downhole tool made of a carbide-reinforced matrix composite. For example, the molten binder material can flow in and fill the voids between the individual particles of the tungsten carbide powder to form the casting matrix body of the downhole tool. In some embodiments, more binder material than is required to form the body can be placed in the mold to allow the carbide-reinforced matrix composite to be formed by pressure permeation. For example, once melted, the excess binder material applies downward pressure, which forces the liquid binder to flow between the particles of the carbide material to form the matrix. In a particular example, the tungsten carbide particles can reinforce a copper alloy matrix. The mold and body can be removed from the furnace and allowed to cool. In operation 2710, the downhole tool body can be removed from the mold. For example, the mold can be cut or otherwise damaged to expose the body of the downhole tool. The drill shank, drill bit loading / unloading surface, and connectors for attaching the drill bit to the drill string can be welded to the headstock. Replacement components can be removed from the body of the downhole tool, which can create cutting recesses on the tool's cutting edges.

[0147] The cutting recesses can be cleaned using one or more tools to ensure that their size and shape are designed to receive the corresponding cutting elements. In operation 2712, cutting elements can be inserted into each of the cutting recesses. At least some of the cutting elements may have a non-circular cross-section that substantially matches the non-circular cross-section of the corresponding cutting recess in the cutting recess. In some embodiments, the shape and orientation of each cutting recess and the corresponding cutting element disposed within it are selected such that when the corresponding cutting element is inserted into the cutting recess, it is oriented such that its cutting tip protrudes beyond the top surface of the corresponding cutting edge among a plurality of cutting edges. The cutting recesses can define the shape, size, and orientation (e.g., tilt angle, back tilt angle, side tilt angle, cutting tip rotation, etc.) of the cutting elements positioned therein. Once inserted into the recesses, each cutting element can be brazed to a downhole tool, for example using a process similar to method 2600.

[0148] Figure 28 This is a flowchart illustrating the operation of a method 2800 for manufacturing downhole tools according to some embodiments of the present invention. Method 2800 can be used to manufacture downhole tools (e.g., drill bits 100, 200, 1500, reamers 300, and / or other downhole tools) including non-cylindrical cutting elements (e.g., cutting elements 400-1600). In particular, method 2800 can be used to manufacture steel-bodied downhole tools. Method 2800 can begin with operation 2802, in which the body of the downhole tool is formed. Forming the body of the downhole tool can be performed, for example, by machining the body from a steel billet using a computer numerical control (CNC) milling machine and / or other machining tools. The body may include a plurality of inserts, each defining a plurality of cutting element recesses. As described herein, at least some of the cutting element recesses may have a non-circular cross-section. Machining such non-cylindrical recesses can be accomplished by producing rounded corners using single-sided undercut, double-sided undercut, and / or other machining techniques for generating square or other non-circular voids. In some embodiments, the cutting recess may have a feature parallel to the axis of the cutting part with a radius less than 0.1 inches, or it may have a chamfer and / or sharp corners. In other embodiments, a cylindrical recess may be formed first, and then a gasket may be welded into the recess to change the cross-sectional shape of the recess.

[0149] In operation 2804, the body of the downhole tool can be surface hardened. For example, heat can be applied to at least a portion of the downhole tool body and a surface hardening material to fuse the surface hardening material to at least a portion of the body (e.g., the cutting edge). The surface hardening material may include a carbide material and a binder, which, when fused to the body, can harden the body and make it more wear-resistant. In operation 2806, cutting elements can be inserted into each cutting element recess in a cutting element recess. At least some of the cutting elements may have a non-circular cross-section that substantially matches the non-circular cross-section of a corresponding cutting element recess in the cutting element recess. In some embodiments, the shape and orientation of each cutting element recess and the corresponding cutting element disposed within the cutting element recess are selected such that when the corresponding cutting element is inserted into the cutting element recess, the corresponding cutting element is oriented such that the cutting tip of the corresponding cutting element protrudes beyond the top surface of the corresponding cutting edge among a plurality of cutting edges. The cutting recess can define the shape, size, and orientation of the cutting element positioned therein (e.g., tilt angle, back tilt angle, side tilt angle, cutting tip rotation, etc.). Once inserted into the recess, each cutting element can be brazed to the downhole tool in operation 2808, for example using a process similar to method 2600.

[0150] As described above, using a non-cylindrical cutting element comprising multiple discrete cutting tips allows for the reuse of the cutting element. For example, during drilling or reaming operations, typically only one cutting tip will experience significant wear. This allows other cutting tips (e.g., those recessed into the insert) to remain in a usable condition. Figure 29This is a flowchart illustrating the operation of a method 2900 for reorienting a cutting element in a downhole tool according to some embodiments of the invention. Method 2900 can be used with any drill bit and / or cutting element described herein, such as those having multiple discrete cutting tips and having a non-circular cross-section (corresponding to the cross-section of a cutting element recess in which the cutting element is fixed). Method 2900 may begin with operation 2902, in which it is determined that a first cutting tip of the cutting element on the insert of the downhole tool is excessively worn. The first cutting tip may protrude above the top surface of the insert and be in a cutting position. For example, this determination can be made by grading the first cutting tip based on one or more predetermined criteria. For example, one or more wear marks and / or wear planes can be compared to standards established by the International Association of Drilling Contractors (IADC). It can be assessed whether any chips, cracks, or spalling extend beyond a threshold percentage of the cut length; whether any cobalt leaching is present on the diameter of the cut / cutting tip; whether any cobalt erosion is present near the cutting tip; whether graphitization, spalling, fragmentation, diamond detachment, cracking, and / or other wear is present on the cutting tip; and / or other grading techniques can be used. If the first cutting tip is damaged / worn to the point of being unusable, method 2900 may include, in operation 2904, determining whether a second cutting tip among the discrete cutting tips is in a condition sufficient for use in the cutting position. For this purpose, an evaluation using one or more similar grading standards can be performed on the second cutting tip.

[0151] If the second cutting tip meets the grading criteria, the cutting element can be removed from the cutting element recess in operation 2906. For example, heat (e.g., using a blowtorch) can be applied to the cutting element and insert to remelt the brazing alloy used to hold the cutting element in the cutting element recess. The cutting element is then pulled out of the cutting element recess to disengage. In operation 2908, the cutting element can be rotated and inserted into the cutting element recess, wherein the second cutting tip is oriented in the cutting position. In operation 2910, the cutting element can be secured in the cutting element recess, for example, by re-brazing the cutting element into the cutting element recess using a process similar to method 2600. The shape and orientation of the cutting element recess can be selected such that when the cutting element is inserted into the cutting element recess, the cutting element is oriented such that one of the discrete cutting tips is in the cutting position. This eliminates the need for installers to manually align the cutting tips along the desired direction.

[0152] Figure 30Operation of a method 3000 using a downhole tool according to the present invention is illustrated. The downhole tool may be a drill bit, reamer, or other rotatable tool as described herein (e.g., drill bit 100, 200, 1500, reamer 300, and / or other downhole tools), and may include non-cylindrical cutting elements (e.g., cutting elements 400-1600) on a plurality of blades. In operation 3002, the downhole tool may be rotated to shear and / or clear subsurface formations and / or extend the wellbore. The downhole tool may be rotated in a variety of ways. For example, the downhole tool may be coupled to a drill string rotated by a top drive or platform drive (not shown), or to a downhole motor as part of a bottomhole assembly. The downhole tool may be surrounded by the sidewalls of the wellbore. In operation 3004, as the downhole tool rotates within the wellbore via the drill string, drilling fluid may be pumped down the drill string through internal passages within the downhole tool and pumped out through openings, nozzles, or ports. Cuttings generated by one or more PDC cutting elements of the downhole tool can be carried by drilling fluid through the channel, around the downhole tool, and back up the wellbore through the annulus located inside the wellbore and outside the drill string.

[0153] It should be noted that the methods, systems, and apparatuses discussed above are intended to be illustrative only. It must be emphasized that various procedures or components may be omitted, substituted, or added as appropriate in the various embodiments. Furthermore, features described for some embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. Moreover, it should be emphasized that technology is constantly evolving, and therefore, many of the elements are merely exemplary and should not be construed as limiting the scope of the invention. Some embodiments are described as processes in the form of flowcharts or block diagrams. While each flowchart or block diagram may describe operations as a sequential process, many operations within the operations may be performed in parallel or simultaneously. Additionally, the order of operations may be rearranged. The process may have additional steps not included in the figures.

[0154] This specification provides specific details to offer a thorough understanding of the embodiments. However, those skilled in the art will understand that these embodiments can be practiced even without these specific details. For example, well-known structures and techniques have been shown without unnecessary detail to avoid obscuring the embodiments. This description provides exemplary embodiments only and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the foregoing description of the embodiments will provide those skilled in the art with an enabling description for practicing the embodiments of the invention. Various changes can be made to the function and arrangement of elements without departing from the spirit and scope of the invention.

[0155] Furthermore, the words “comprising,” “including,” “having,” “with,” “covering,” and “featured” used in this specification and the following claims are intended to describe the presence of a specified feature, integral, component, or step, but do not preclude the presence or addition of one or more other features, integrals, components, steps, actions, or groups.

[0156] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly or conventionally understood. As used herein, the articles “a” and “an” refer to one or more (i.e., at least one) grammatical objects of the article. For example, “a element” refers to one element or more elements. When referring to measurable values ​​such as quantity, duration, etc., the use of “about” and / or “approximately” herein includes a variation of ±20% or ±10%, ±5% or +0.1% from the specified value, as such variation applies to the context of the systems, devices, loops, methods, and other embodiments described herein. When referring to measurable values ​​such as quantity, duration, physical properties (e.g., frequency), the use of “generally” herein also includes a variation of ±20% or ±10%, ±5% or +0.1% from the specified value, as such variation applies to the context of the systems, devices, loops, methods, and other embodiments described herein. As used in the context of shape, the terms “basically” and “generally” should be understood to mean that a large percentage (e.g., greater than 70%, greater than 80%, greater than 90% or higher) of the shape of a component has the described shape; however, some smaller percentages of the component may deviate from the described shape. For example, a component may include several protrusions, cutouts, and / or small parts that prevent the component from perfectly matching the described shape.

[0157] When a numerical range is provided, it should be understood that, unless the context explicitly specifies otherwise, the smallest portion of each intermediate value between the upper and lower limits of the range, up to the lower limit unit, is also specifically disclosed. Any narrower range between any specified value or any unspecified intermediate value within the specified range and any other specified value or intermediate value within the specified range is included. The upper and lower limits of these narrower ranges may be independently included or excluded from the range, and each range that includes any limit, does not include any limit, or includes both limits is also included in this solution, subject to any explicitly excluded limits within the specified range. Where a specified range includes one or two limits, ranges that exclude any or both of these included limits are also included.

[0158] As used herein (including the claims), the use of "and" in a list of items beginning with "at least one of..." or "one or more of..." indicates that any combination of the listed items may be used. For example, a list of "at least one of A, B, and C" includes any combination of A or B or C or AB or AC or BC and / or ABC (i.e., A and B and C). Furthermore, multiple uses of A, B, and / or C may also constitute part of the considered combination if the appearance or use of item A, B, or C is likely to occur or be used more than once. For example, a list of "at least one of A, B, and C" may also include AA, AAB, AAA, BB, etc.

Claims

1. A downhole tool comprising: a body including a face and an axis of rotation; a plurality of blades disposed on the face of the body, each of the plurality of blades defining a plurality of cutter pockets, wherein at least one of the plurality of cutter pockets includes a non-circular cross-section; and a plurality of cutters, a portion of each cutter disposed within a respective one of the plurality of cutter pockets, wherein the portion of each cutter has a cross-sectional shape that matches a cross-sectional shape of the respective cutter pocket.

2. The downhole tool of claim 1, wherein: the downhole tool comprises a drill bit.

3. The downhole tool of claim 1, wherein: the downhole tool comprises a reamer.

4. The downhole tool of claim 1, wherein: the at least one cutter pocket has a generally rectangular cross-section.

5. The downhole tool of claim 4, wherein: the generally rectangular cross-section includes two orthogonal straight sides and rounded corners coupling the two orthogonal straight sides.

6. The downhole tool of claim 5, wherein: each rounded corner has a width between 5 degrees and 45 degrees, measured from a central axis of the cutter pocket.

7. The downhole tool of claim 1, wherein: the blades include a plurality of knuckles; and each of the plurality of knuckles protrudes from a top surface of one of the plurality of blades, aligns with a respective one of the plurality of cutter pockets, and supports a portion of a base of one of the plurality of cutters seated within the respective one of the plurality of cutter pockets.

8. The downhole tool of claim 7, wherein: each of the plurality of knuckles has a shape and size that substantially corresponds to a shape and size of a portion of the one of the plurality of cutters extending above a top surface of the respective one of the plurality of blades on which the one of the plurality of cutters is mounted.

9. The downhole tool of claim 7, wherein: a top surface of each of the plurality of knuckles tapers downwardly in a direction away from the one of the plurality of cutters toward the top surface of the respective one of the plurality of blades.

10. The downhole tool of claim 7, wherein: each of the plurality of knuckles is axially aligned with a respective one of the plurality of cutters.

11. The downhole tool of claim 1, wherein: the body includes a plurality of channels, each channel formed between adjacent ones of the plurality of blades; the body includes a plurality of nozzles, each nozzle disposed within one of the plurality of channels; and an outlet of each nozzle is aligned with one of the plurality of cutters facing the respective channel.

12. The downhole tool of claim 1, wherein: At least one of the plurality of cutters includes a diamond table having a non-cylindrical periphery configured to rotate about a central axis of the at least one of the plurality of cutters in the respective cutter pocket at an angle between 60 degrees and 300 degrees to expose new cutting edges with a point load capacity greater than a point load capacity of a conventional cylindrical cutter having a similar size while maintaining a brazing gap thickness of 0.015 inches or less over 85% or more of a brazable surface area of the conventional cylindrical cutter having a similar size.

13. The downhole tool of claim 1, wherein: the shape and orientation of the at least one cutter pocket and the respective one of the cutters disposed within the at least one cutter pocket are selected such that, when the respective one of the cutters is inserted into the at least one cutter pocket, the respective one of the cutters is oriented such that a cutting tip of the respective one of the cutters protrudes beyond a top surface of the respective one of the plurality of blades.

14. A cutter for a downhole tool, the cutter comprising: a substrate including a brazing surface, wherein at least a portion of the brazing surface includes a first non-circular cross-section; and a diamond table further comprising: a bottom surface joined to the substrate; and a cutting face opposite the bottom surface, the cutting face including a second non-circular cross-section.

15. The cutter for a downhole tool of claim 14, wherein: one or both of the first non-circular cross-section and the second non-circular cross-section includes one or more concave and / or convex regions.

16. The cutter for a downhole tool of claim 14, wherein: the cutting face is non-planar.

17. The cutter for a downhole tool of claim 14, wherein: the cutting face includes a plurality of discrete cutting tips.

18. The cutter for a downhole tool of claim 14, wherein: one or both of the first non-circular cross-section and the second non-circular cross-section includes a generally quadrilateral shape.

19. The cutter for a downhole tool of claim 14, wherein: the cutter is symmetric about two perpendicular planes extending through both the substrate and the diamond table.

20. The cutter for a downhole tool of claim 14, wherein: one or both of the first non-circular cross-section and the second non-circular cross-section includes two or more straight sides connected via a plurality of curved corners.

21. The cutter for a downhole tool of claim 20, wherein: a ratio of a length of the straight sides to a length of the curved corners is at least 0.5:

1.

22. The cutter for a downhole tool of claim 14, wherein: one or both of the first non-circular cross-section and the second non-circular cross-section includes a generally rectangular shape.

23. The cutter for a downhole tool of claim 22, wherein: The generally rectangular shape includes four straight sides and four rounded corners.

24. The cutting element for a downhole tool of claim 14, wherein: One or both of the first and second non-circular cross-sections includes a generally triangular shape.

25. The cutting element for a downhole tool of claim 24, wherein: The generally triangular shape includes three straight sides and three rounded corners.

26. The cutting element for a downhole tool of claim 14, wherein: One or both of the first and second non-circular cross-sections includes a stadium shape.

27. The cutting element for a downhole tool of claim 14, wherein: The diamond table includes a chamfered edge extending from the cutting face to a lateral side of the diamond table.

28. The cutting element for a downhole tool of claim 27, wherein: An angle of the chamfered edge relative to the cutting face varies along a perimeter of the cutting face.

29. The cutting element for a downhole tool of claim 28, wherein: The angle of the chamfered edge relative to the cutting face at a cutting region of the cutting face is greater than the angle of the chamfered edge relative to the cutting face at a middle region of the cutting face.

30. The cutting element for a downhole tool of claim 28, wherein: The angle of the chamfered edge relative to the cutting face at a cutting region of the cutting face is less than the angle of the chamfered edge relative to the cutting face at a middle region of the cutting face.

31. The cutting element for a downhole tool of claim 27, wherein: A depth of the chamfered edge varies along a perimeter of the cutting face.

32. The cutting element for a downhole tool of claim 31, wherein: The depth of the chamfered edge at a cutting region of the cutting face is greater than the depth of the chamfered edge at a middle region of the cutting face.

33. The cutting element for a downhole tool of claim 31, wherein: The depth of the chamfered edge at a cutting region of the cutting face is less than the depth of the chamfered edge at a middle region of the cutting face.

34. The cutting element for a downhole tool of claim 14, wherein: The base includes a non-planar interface protruding from the base in a direction of the diamond table, the non-planar interface including a non-circular cross-section.

35. The cutting element for a downhole tool of claim 34, wherein: A shape of an outer periphery of the non-planar interface matches a shape of an outer periphery of a topmost planar surface of the base.

36. The cutting element for a downhole tool of claim 34, wherein: A thickness of the non-planar interface varies over a surface area of the non-planar interface.

37. The cutting element for a downhole tool of claim 36, wherein: A thickness of the diamond table varies over a surface area of the diamond table; and Variations in the thickness of the non-planar interface correspond to variations in the thickness of the diamond table across the surface area of the diamond table.

38. The cutting element for a downhole tool of claim 34, wherein: the diamond table includes a protruding feature; and the thickness of the non-planar interface increases in the region corresponding to the protruding feature.

39. The cutting element for a downhole tool of claim 34, wherein: the diamond table includes a recessed feature; and the thickness of the non-planar interface decreases in the region corresponding to the recessed feature.

40. The cutting element for a downhole tool of claim 34, wherein: the distance from the peripheral edge of the non-planar interface to the peripheral edge of the diamond table is uniform to within 20% of the maximum distance from the peripheral edge of the non-planar interface to the peripheral edge of the diamond table across the entire periphery of the diamond table.

41. The cutting element for a downhole tool of claim 34, wherein: the first non-circular cross-section and the second non-circular cross-section comprise the same shape.

42. A cutting element for a downhole tool, comprising: a diamond table having a non-cylindrical outer periphery configured to rotate within a cutting element pocket of a downhole tool at an angle between 60 degrees and 300 degrees about a central axis of the diamond table so as to expose new cutting edges having a point load capacity greater than a point load capacity of a conventional cylindrical cutting element of similar size while maintaining a brazing gap thickness of 0.015 inches or less over 85% or more of the brazeable surface area of the conventional cylindrical cutting element of similar size.

43. A cutting element for a downhole tool, comprising: a body having a central axis, wherein a radial distance between an outer surface of the cutting element and the central axis varies around the outer periphery of the body along at least 50% of the outer periphery and along at least 50% of the length of the body.

44. A method of incorporating a cutting element into a downhole tool, comprising: inserting a cutting element having a non-circular cross-section into a non-cylindrical pocket formed in a downhole tool such that a gap is formed between an outer face of the cutting element and a wall of the pocket; providing a metal-containing substance into the gap; and securing the cutting element in the pocket such that the cutting element is joined to the downhole tool.

45. The method of incorporating a cutting element into a downhole tool of claim 44, wherein: the metal-containing substance comprises a braze alloy.

46. The method of incorporating a cutting element into a downhole tool of claim 44, wherein: the pocket and the cutting element each have a generally rectangular cross-section.

47. The method of incorporating a cutting element into a downhole tool of claim 44, wherein: the pocket and the cutting element each have a generally triangular cross-section.

48. The method of incorporating a cutting element into a downhole tool of claim 44, wherein: the pocket and the cutting element each have a generally stadium-shaped cross-section. ​ 49. The method of incorporating cutters into a downhole tool of claim 44, wherein: the pocket and the cutters each have a generally pentagonal cross-section.

50. The method of incorporating cutters into a downhole tool of claim 44, wherein: the pocket and the cutters each have a generally hexagonal cross-section.

51. The method of incorporating cutters into a downhole tool of claim 44, wherein: the pocket is formed in a blade extending outwardly from a face of the downhole tool.

52. The method of incorporating cutters into a downhole tool of claim 51, wherein: the shape and orientation of the cutters and the pocket are selected such that when the cutters are inserted into the pocket, the cutters are oriented such that a cutting tip of the cutters protrudes beyond a top surface of the blade.

53. A method of manufacturing a downhole tool, comprising: forming a mold of a body of the downhole tool; inserting a plurality of cutter pocket inserts into the mold, wherein: the plurality of cutter pocket inserts have a non-circular cross-section; and the plurality of cutter pocket inserts are aligned within the mold such that the cutter pocket inserts define a size and orientation of a cutter pocket; filling the mold with a carbide matrix material and a binder material; heating the filled mold to form the body of the downhole tool, wherein: the plurality of cutter pocket inserts form a cutter pocket within the body of the downhole tool; and at least one of the cutter pockets includes a non-circular cross-section configured to automatically orient a cutter in a cutting position; removing the body of the downhole tool from the mold; and inserting a cutter into at least one of the cutter pockets, wherein at least one of the cutters has a non-circular cross-section that substantially matches the non-circular cross-section of a corresponding one of the cutter pockets.

54. The method of manufacturing a downhole tool of claim 53, wherein: inserting the plurality of cutter pocket inserts into the mold includes inserting each cutter pocket insert into a groove formed in the mold.

55. The method of manufacturing a downhole tool of claim 54, wherein: each of the plurality of cutter pocket inserts is aligned within a corresponding one of the cutter pockets by manual means.

56. The method of manufacturing a downhole tool of claim 54, wherein: each of the plurality of cutter pocket inserts is aligned within a corresponding one of the cutter pockets by use of indexing features formed in one or both of the mold and the corresponding cutter pocket insert.

57. The method of manufacturing a downhole tool of claim 54, wherein: one of the groove and the corresponding cutter pocket insert includes a ridge and the other of the groove and the corresponding cutter pocket insert defines a groove; and the corresponding cutter pocket insert is aligned within the groove by inserting the ridge into the groove.

58. The method of manufacturing a downhole tool of claim 54, wherein: one of the groove and corresponding cutting element pocket replacement includes a convex surface, the other of the groove and corresponding cutting element pocket replacement defines a concave surface; and the corresponding cutting element pocket replacement is aligned within the groove by opposing the concave surface with the convex surface.

59. The method of manufacturing a downhole tool of claim 54, wherein: each of the groove and corresponding cutting element pocket replacement defines a slot; and a key is inserted within both slots to align the corresponding cutting element pocket replacement within the groove.

60. The method of manufacturing a downhole tool of claim 53, further comprising: removing the cutting element pocket replacement from the body of the downhole tool prior to inserting a cutting element.

61. The method of manufacturing a downhole tool of claim 53, further comprising: brazing each cutting element within a corresponding cutting element pocket.

62. The method of manufacturing a downhole tool of claim 53, wherein: the body of the downhole tool includes a plurality of blades extending away from the body of the downhole tool; and a shape and orientation of each cutting element pocket and corresponding cutting element disposed within the cutting element pocket is selected such that when the corresponding cutting element of the cutting elements is inserted into the cutting element pocket, the corresponding cutting element of the cutting elements is oriented such that a cutting tip of the corresponding cutting element of the cutting elements protrudes beyond a top surface of a corresponding blade of the plurality of blades.

63. A method of manufacturing a downhole tool, comprising: forming a body of a downhole tool, wherein the body includes a plurality of blades, each blade defining a plurality of cutting element pockets, wherein at least one cutting element pocket of the plurality of cutting element pockets has a non-circular cross-section; hard-facing the body of the downhole tool; inserting a cutting element into each cutting element pocket of the plurality of cutting element pockets, wherein at least one cutting element has a non-circular cross-section that substantially matches a non-circular cross-section of a corresponding cutting element pocket of at least one cutting element pocket of the plurality of cutting element pockets; brazing each cutting element into the corresponding cutting element pocket of the cutting element pocket.

64. The method of manufacturing a downhole tool of claim 63, wherein: forming the body of the downhole tool includes machining the body from a steel blank.

65. The method of manufacturing a downhole tool of claim 63, wherein: hard-facing includes fusing carbide material and a binder onto at least a portion of the body of the downhole tool.

66. The method of manufacturing a downhole tool of claim 63, wherein: The shape and orientation of both the respective one of the plurality of cutters and the respective one of the plurality of cutter pockets in which the respective one of the plurality of cutters is disposed are selected such that, when the respective one of the plurality of cutters is inserted into the respective one of the plurality of cutter pockets, the respective one of the plurality of cutters is oriented such that a cutting tip of the respective one of the plurality of cutters protrudes beyond a top surface of a respective one of the plurality of blades.

67. The method of manufacturing a downhole tool of claim 63, wherein: forming the body of the downhole tool includes machining each of the plurality of cutter pockets into the body of the downhole tool.

68. The method of manufacturing a downhole tool of claim 63, wherein: forming the body of the downhole tool includes: forming each of the plurality of cutter pockets to have a circular cross-section, and welding a shim into the circular cross-section to form the non-circular cross-section.

69. A method of re-orienting a cutter to a downhole tool, the method comprising: determining that a first cutting tip of a cutter on a blade of a downhole tool is excessively worn, wherein: the first cutting tip is in a cutting position in which the first cutting tip protrudes above a top surface of the blade; the cutter includes a plurality of discrete cutting tips; and the cutter includes a non-circular cross-section that corresponds to a cross-section of a cutter pocket in which the cutter is secured; determining that a second cutting tip of the plurality of discrete cutting tips is in a condition sufficient to be used in the cutting position; removing the cutter from the cutter pocket; rotating the cutter and inserting the cutter into the cutter pocket, wherein the second cutting tip is oriented into the cutting position; and securing the cutter within the cutter pocket.

70. The method of re-orienting a cutter to a downhole tool of claim 69, wherein: securing the cutter within the cutter pocket includes brazing the cutter to the cutter pocket.

71. The method of re-orienting a cutter to a downhole tool of claim 69, wherein: the shape and orientation of the cutter pocket and the cutter are selected such that, when the cutter is inserted into the cutter pocket, the cutter is oriented such that one of the plurality of discrete cutting tips is in the cutting position.

72. The method of re-orienting a cutter to a downhole tool of claim 69, wherein: determining that a first cutting tip of a cutter on a blade of a downhole tool is excessively worn is accomplished by grading the first cutting tip based on one or more predetermined criteria.

73. The method of re-orienting a cutter to a downhole tool of claim 69, wherein: determining that a second cutting tip of the plurality of discrete cutting tips is in a condition sufficient to be used in the cutting position is accomplished by grading the second cutting tip based on one or more criteria.

74. A drill bit, comprising: a body comprising a face for engaging a bottom of a borehole, the body comprising an axis of rotation extending along a length of the body; a plurality of blades formed on the body; a plurality of cutters mounted on each of the plurality of blades, wherein: the plurality of cutters comprises pairs of cutters, wherein each pair of cutters comprises a first cutter and a second cutter, both of which are the same radial distance from the axis of rotation; one or both of the first cutter and the second cutter in each pair of cutters comprises a plurality of discrete cutting tips; and each cutter is mounted on a respective blade, wherein a single cutting tip extends beyond a top surface of the respective blade.

75. The drill bit of claim 74, wherein: at least some of the pairs of cutters are located on the same blade.

76. The drill bit of claim 74, wherein: at least some of the pairs of cutters are located on different blades.

77. The drill bit of claim 74, wherein: one of the first cutter and the second cutter in each pair of cutters comprises a cylindrical cutter.

78. The drill bit of claim 74, wherein: the first cutter and the second cutter in each pair of cutters comprise the same cutting tip.

79. The drill bit of claim 74, wherein: the first cutter and the second cutter in each pair of cutters comprise different cutting tips.

80. The drill bit of claim 74, wherein: the first cutter and the second cutter in each pair of cutters comprise different cross-sectional shapes.

81. A drill bit to extend a borehole, comprising: a body comprising a face for engaging a bottom of a borehole, the body comprising an axis of rotation extending along a length of the body; a plurality of blades formed on the body; and a plurality of cutters mounted on each of the plurality of blades, wherein: at least one of the blades is an offset blade, the offset blade comprising: an inner region supporting an inner set of cutters of the plurality of cutters along a first leading edge portion of the offset blade; and an outer region supporting an outer set of cutters along a second leading edge portion of the offset blade; the second leading edge portion is rotationally offset from the first leading edge portion; at least some of the plurality of cutters comprise a plurality of discrete cutting tips; and each cutter is mounted on a respective blade, wherein a single cutting tip of the plurality of discrete cutting tips extends beyond a top surface of the respective blade.

82. The drill bit to extend a borehole of claim 81, wherein: the at least some cutters comprise the inner set of cutters.

83. The drill bit to extend a borehole of claim 81, wherein: the at least some cutters comprise the outer set of cutters.

84. The drill bit to extend a borehole of claim 81, wherein: the at least some cutters comprise both the inner set of cutters and the outer set of cutters.

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