BIT WITH CO-RADIAL CUTTING PROFILE AND CUTTING ELEMENT

Abstract

A cutting tool may include multiple blades extending from a bit body, and multiple cutting elements coupled to the blades. First cutting elements and a second cutting element coupled to the blades may collectively define a cutting profile of the bit. The second cutting element may be substantially larger than at least some of the first cutting elements and may substantially define a nose region of the cutting profile.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of, and priority to, U.S. Patent Application Ser. No. 61/976,046, filed Apr. 7, 2014 and titled “BIT WITH CO-RADIAL CUTTING PROFILE AND CUTTING ELEMENT,” which application is incorporated herein by this reference in its entirety.

BACKGROUND

A wellbore may be extended into a subterranean formation by rotating a drill bit at the end of a drill string. While applying weight via the drill string, the drill bit engages and removes material from the formation. Removal of the material may occur by abrasion, fracturing, shearing, or other manners. The diameter of the wellbore may be proportional or otherwise related to the diameter of the cutting profile of the drill bit. Thus, larger diameter drill bits are utilized in larger diameter wellbores, and smaller diameter drill bits are utilized in smaller diameter wellbores. However, as the diameter of a wellbore decreases, the availability of certain types of cutting elements (e.g., polycrystalline diamond compact (“PDC”) cutters) may be limited. These factors may also restrict cutting element placement, such as may be due to manufacturing tolerances, physical interferences, and other factors.

Similar drill bits may also be utilized to remove scale from within a wellbore. In such implementations, scale builds from the outside of the wellbore or within a tubular in the wellbore. The amount of scale may vary along the length of the wellbore, thereby changing the shear, impact, or other forces experienced by the drill bit.

SUMMARY

Embodiments of the present disclosure may relate to a cutting tool that includes multiple blades extending from a bit body. Two different types of cutting elements may be located on the blades. The second type of cutting elements may substantially define a nose region of the cutting profile and may be substantially larger than the first type of cutting elements. The two different cutting elements may differ by size, shape, construction, materials, or in other manners.

In some embodiments, an apparatus that may be used for a drilling, milling, reaming, scaling, or other operation may include a bit body with multiple blades coupled thereto. Cutting elements may be positioned on a corresponding one of the blades and may define a cutting profile with a nose region between a cone region and a gage region. The nose region may be nearest a central axis of the bit body, and the gage region may be furthest from the central axis. The nose region may be shaped to have a radius substantially equal to, and potentially defined by, a first type of cutting element. The first type of cutting element may have a diameter or size substantially different than a diameter or size of a second type of cutting element located at the cone and/or gage regions of the cutting profile.

According to some embodiments, a method includes urging a bit toward a downhole end of a wellbore and dislodging material from the wellbore by rotating the bit. The bit used to dislodge material may include multiple cutting elements that collectively define a cutting profile with a nose region between cone and gage regions. A radius of the nose region may be substantially equal to, and co-radial with, a first set of cutting elements. A second set of cutting elements may be positioned at the cone and gage regions and may have a smaller diameter than the first set of cutting elements.

A method for designing a bit is also described, and may include selecting a first size of a cutting element. A second size of cutting elements may also be selected to be different than the first size. After selecting the first size of a cutting element, a cutting profile can be created with a nose region and potentially other regions. The nose region may be created to have a nose radius substantially equal to a radius of the first size of a cutting element. Cutting elements of the different sizes can be arranged on multiple blades of a bit having the cutting profile to position the first size of cutting element co-radial with the nose region and the second size of cutting elements in the other regions of the cutting profile.

This summary is provided to introduce a selection of concepts that are further described in the description that follows. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Accordingly, additional aspects of the present disclosure are set forth in the description that follows, and/or may be learned by a person having ordinary skill in the art by reading the materials herein and/or practicing the principles described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be understood from the following detailed description when read with the accompanying figures. While the drawings illustrate certain components at a relative scale that may be used in some implementations of such embodiments, it is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale for other implementations or embodiments. In some drawings, the dimensions of the various features may be increased or reduced for clarity of discussion.

FIG. 1 is a schematic illustration of a portion of a drilling system according to one or more aspects of the present disclosure.

FIG. 2 is a perspective view of a bit according to one or more aspects of the present disclosure.

FIG. 3 is a section view of a portion of a bit, with cutting elements defining a cutting profile and presented in a rotationally aggregated view, according to one or more aspects of the present disclosure.

FIG. 4 is a schematic, rotationally aggregated view of cutting elements defining a portion of a bit profile according to one or more aspects of the disclosure.

FIG. 5 is a schematic, rotationally aggregated view of cutting elements defining a portion of a bit profile according to one or more aspects of the present disclosure.

FIG. 6 is a perspective view of a portion of a bit according to one or more aspects of the present disclosure.

FIG. 7 is a perspective view of multiple cutting elements as they may be positioned on a bit, according to one or more aspects of the present disclosure.

FIG. 8 is a schematic, rotationally aggregated view of cutting elements defining a portion of a bit profile according to one or more aspects of the present disclosure.

FIG. 9 is a flow-chart diagram of a method for designing a bit according to one or more aspects of the present disclosure

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments of the present disclosure. Specific examples of components and arrangements are described to simplify the present disclosure. These are merely examples, and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

FIG. 1 is a schematic view of a portion of a drilling system according to one or more aspects of the present disclosure. Depicted components include a wellsite 10, a rig 15, and a bottom-hole assembly (“BHA”) 20 suspended from the rig 15 in a wellbore 12 via a drill string and/or another string of tubular members 25. The BHA 20 may include or be coupled to a bit 30 at its lower or distal end, which may be operable to advance into a formation 35 and form or extend the wellbore 12. The bit 30 may be, include, form a portion of, or otherwise have one or more aspects in common with the example bit implementations described herein and/or other bits within the scope of the present disclosure (e.g., drill bits, milling bits, underreamers, etc.).

The string of tubular members 25 may be rotated by a rotary table 40 that engages a kelly (not shown) at an upper end of the string of tubular members 25. The string of tubular members 25 may be suspended from a hook 45 attached to a traveling block (not shown) through the kelly and a rotary swivel 50 that permits rotation of the string of tubular members 25 relative to the hook 45.

The rig 15 is depicted as a land-based kelly platform and derrick assembly utilized to form the wellbore 12 by rotary drilling; however, a person having ordinary skill in the art will appreciate that one or more aspects of the present disclosure may also find application in other downhole implementations, including off-shore rigs, and is not limited to land-based rigs. Moreover, the one or more aspects of the present disclosure may be used in connection with different types of land-based rigs (e.g., electrical, hydraulic, conventional, coil tubing, single drill pipe, double drill pipe, etc.) and different types of off-shore rigs (e.g., fixed platform, floating production, tension leg, subsea, compliant tower, sea star, SPAR platform, etc.). A person having ordinary skill in the art will also recognize in view of the present disclosure that one or more aspects of the present disclosure may be applicable or readily adaptable for use with top drive systems in lieu of or addition to a rotary table 40.

Drilling fluid 55 may be stored in a reservoir 60 at the wellsite 10. The reservoir 60 may include a tank, a pit formed in the ground, some other type of storage, or a combination of the foregoing. The drilling fluid 55 may include so-called drilling mud, or any fluid suitable for use within a drilling system. A pump 65 may be used to deliver drilling fluid 55 to the interior of the string of tubular members 25 via a port in the rotary swivel 50, thereby inducing the drilling fluid to flow downward through the string of tubular members 25, as indicated in FIG. 1 by directional arrow 70. The drilling fluid 55 may then exits via ports in the bit 30, and then circulate upward as indicated in FIG. 1 by direction arrows 75, through an annulus defined between the outside of the string of tubular members 25 and the interior wall of the wellbore 12. In this manner, the drilling fluid 55 may lubricate the bit 30, carry formation cuttings up to the surface, and be returned to the reservoir 60 for recirculation.

The BHA 20 may be positioned near the bit 30, perhaps within the length of several drill collars and/or other tubular members 25 from the bit 30. The BHA 20 may include various components with various capabilities providing steerability of the bit 30, and may be further operable to facilitate the measuring, processing, or storing of information about the BHA 20 and/or the subterranean formation 35. A telemetry device (not shown) may also be provided for communicating with one or more components of surface equipment 14. Example surface equipment 14 may include acquisition, control, automation, user interface, other equipment, or some combination of the foregoing.

FIG. 2 is a perspective view of an example implementation of a bit 200 according to one or more aspects of the present disclosure. The bit 200 is illustrative of an example bit that may be used in a drilling, milling, coiled tubing, or other system, including within the drilling system illustrated in FIG. 1. The bit 200 may be a fixed-cutter or drag bit having a bit body 210. The bit body 210 may be integral with or otherwise coupled to a threaded connection 212, which is shown as extending from the bit body 210 for connecting the bit 200 to a drill string, drill collar, drilling tubular, or other component (e.g., a BHA component). In some implementations, the threaded connection 212 may be or include a pin (or male portion) of a threaded pin-box connection. Operations involving the bit 200 may include rotating the bit 200 in a cutting direction 202 around a central axis 204.

A bit face 220 may support blades 230, 232, 234, 240, 242, and 244. In the illustrated embodiment, the bit face 220 may include or otherwise support primary blades 230, 232, and 234, as well as secondary blades 240, 242, and 244. The primary blades 230, 232, and 234 may be angularly (i.e., azimuthally or circumferentially) offset from each other at a particular angular or azimuthal orientation. Similarly, the secondary blades 240, 242, and 244 may each be angularly and azimuthally offset from each other, and in the illustrated embodiment are shown as being angularly spaced between circumferentially adjacent pairs of the primary blades 230, 232, and 234. The primary blades 230, 232, and 234 and the secondary blades 240, 242, and 244 may extend generally radially from the bit face 220, as well as axially along a portion of the periphery of the bit 200. In some embodiments, the primary blades 230, 232, and 234 may extend radially from the bit face 220 from a position at or near the bit axis 204, while the secondary blades 240, 242, and 242 may extend radially from the bit face 220 from a position that is radially offset from the bit axis 204. As shown in FIG. 2, the primary blades 230, 232, and 234 may extend axially along the bit face 220 to a position at or near the distal or downhole end of the bit 200. In some embodiments, the secondary blades 240, 242, and 244 may not extend to the distal or downhole end of the bit 200. Junk slots 222 may separate the primary blades 230, 232, and 234 and the secondary blades 240, 242, and 244, and permit the passage of drilling fluid and cuttings.

As shown in FIG. 2, one or more pockets 254 may be formed in each primary blade 230, 232, and 234 and/or in each secondary blade 240, 242, and 244. Cutting elements 250 and 252 may be positioned in a corresponding pocket 254 formed in the primary blades 230, 232, and 234 and secondary blades 240, 242, and 244, and welded, brazed, press-fit, or otherwise coupled to the corresponding blade 230, 232, 234, 240, 242, or 244. In other embodiments the cutting elements 250 and 252 may be integral with the corresponding blade 230, 232, 234, 240, 242, or 244, or may be coupled to the bit 200 in other manners that are within the scope of the present disclosure. The pockets 254 may fix the cutting elements 250 and 252 in particular locations and orientations relative to the bit body 210, in some embodiments. In other embodiments, the cutting elements 250 and 252 may be movable within a pocket 254. For instance, the pocket 254 (or the cutting elements 250 and 252) may include a bearing element, or other similar element allowing the cutting elements 250 and 252 to rotate within the pocket 254 and relative to the bit body 210. The cutting elements 250 and 252 may each be arranged, for example, along or proximate a leading edge 236 of a corresponding one of the primary blades 230, 232, and 234 and the secondary blades 240, 242, and 244.

The cutting elements 250 and 252 may each be made of, or include, a material having sufficient hardness and other material properties to cut through the desired formation, cement, scale, or other material, or to mill through steel casing, packers, bridge plugs, tubulars, or other downhole tools. In one embodiment, the cutting elements 250 and/or 252 may include a substrate including tungsten carbide, cobalt cemented tungsten carbide, and/or other materials, and a cutting layer including polycrystalline diamond, polycrystalline cubic boron nitride, other materials, or some combination of the foregoing. In FIG. 2, the substrate and cutting layers may collectively define a substantially cylindrical cutting element 250 and/or 252. In other embodiments, however, the cutting elements 250 and/or 252 may have other shapes or configurations (e.g., domed or semi-round top, conical, frustoconical, lobed, ridged, etc.).

The cutting element 250 may be larger than the cutting elements 252 in some embodiments. For example, the cutting element 250 may have a diameter of thirteen (13) millimeters, and the smaller cutting elements 252 may have a diameter of nine (9) millimeters. Other dimensions are also within the scope of the present disclosure, including without limitation the examples described below in Table 1—Cutting Element Size Combinations.

TABLE 1
Cutting Element Size Combinations
Diameter of cutting element 250	11	11	13	16	19
(mm)
Diameter of cutting elements 252	6	9	6	11	11
(mm)
Size Difference (%)	83%	22%	117%	45%	73%
Size Difference	2	1	3	2	3
(# of standard sizes)

As also shown in Table 1, the size difference between the diameters of the cutting elements 250 and 252 may range between twenty-two percent (22%) and one-hundred seventeen percent (117%). However, other size combinations within the scope of the present disclosure may have a size difference that ranges between fifteen percent (15%) and three hundred percent (300%). In some embodiments, the larger cutting elements 250 may have a diameter that is at least four (4) millimeters larger the diameter of at least some of the smaller cutting elements 252. In other embodiments, the size difference may be greater or less than four (4) millimeters.

The example sizes provided above in Table 1 may be industry-standard sizes for the oil and gas industry (e.g., six (6) millimeters, nine (9) millimeters, eleven (11) millimeters, thirteen (13) millimeters, sixteen (16) millimeters, nineteen (19) millimeters, and twenty-two (22) millimeters), although custom or proprietary sizes may also be used in embodiments of the present disclosure. As shown, the size difference between standard sizes of cutting elements may range between one (1) and three (3) standard sizes. Other size differences are also contemplated. For instance, a cutting element 250 may be four (4) or more standard sizes larger than the cutting elements 252. In some embodiments, a cutting element (e.g., larger cutting element 250) may be “substantially” larger than another cutting element (e.g., smaller cutting element 252) of a bit. As used herein with reference to relative sizes of cutting elements, sizes of cutting elements are considered to be “substantially” different when one cutting element has a diameter that is 25% larger than the diameter of the other cutting element, or when one cutting element is at least two (2) industry-standard sizes smaller or larger than another cutting element.

FIG. 3 is a schematic view of the bit 200 as it would appear with the cutting elements 250 and 252 rotated into an aggregated profile view. In other words, the profile view of the bit 200 as shown in FIG. 3 may depict a position of each cutting element 250, 252 from each primary and/or secondary blade (e.g., blades 230, 232, 234, 240, 242, and 244 of FIG. 2), as if each blade was positioned at the same azimuth at the same time. Such view also depicts a cutting profile 305 (depicted in FIG. 3 by a heavy dark line) collectively formed by an outermost edge 258 of the cutting element 250 and outermost edges 256 of the cutting elements 252.

The cutting profile 305 may include a cone region 310, a nose region 320, a shoulder region 330, a gage region 340, other regions, or a combination of the foregoing. As shown in FIG. 3, the cone region 310 may be radially nearest to the bit axis 204, and the gage region 340 may be radially furthest from the bit axis 204. The nose region 320 may provide a transition from the cone region 310 to the shoulder region 330, or to the gage region 340 if no shoulder region 330 exists. The shoulder region 330 may be included so that the transition between the nose region 320 and the gage region 340 is less abrupt. The gage region 340 may define the diameter or gage of the bit 200, and therefore the wellbore, lateral borehole, casing window, or other opening drilled/milled by the bit 200.

In the example implementation shown in FIG. 3, the outermost edges 256 of four (4) smaller cutting elements 252 may define the cone region 310, the outermost edge 258 of the larger cutting element 250 may define the nose region 320, the outermost edges 256 of six (6) smaller cutting elements 252 may define the shoulder region 330, and the outermost edges 256 of two (2) smaller cutting elements 252 may define the gage region 340. As will be understood by a person having ordinary skill in the art in view of the present disclosure, the boundaries of the cone region 310, the nose region 320, the shoulder region 330, and the gage region 340 are not precisely delineated on the bit 200, but are instead approximate, and are herein identified relative to one another for the purpose of better describing the distribution of the cutting elements 250 and 252 over the bit face 220. Generally, the cone region 310, the shoulder region 330, and the gage region 340 may each be defined by the outermost edges 256 and may number as few as two (2) cutting elements 252, or as many as thirty (30) cutting elements 252.

It is also noted that, within each region (310, 320, 330, and 340), the “number” of cutting elements 250 and 252 whose outermost edges 258 and 256 define the corresponding region may represent the actual number of cutting elements 250 and 252 distributed among the blades (e.g., blades 230, 232, 234, 240, 242, and 244 of FIG. 2) within that region or, as shown in the view in FIG. 3, the number of distinct positions of cutting elements 250 and 252. It should be appreciated in view of the disclosure herein, that the number of positions of cutting elements 250 and 252 may be fewer than the number of actual cutting elements 250 and 252 defining or otherwise arranged or positioned in a corresponding region. For instance, some of the cutting elements 250 and 252 may have the same radial and axial position on the bit 200, but may be located at different azimuths on different ones of the blades (e.g., blades 230, 232, 234, 240, 242, and 244 of FIG. 2). This convention also applies to embodiments shown in figures other than FIG. 3 and/or otherwise within the scope of the present disclosure.

As depicted in FIG. 3, the outermost edges 256 and 258 of the cutting elements 252 and 250, respectively, may define the cutting profile 305 in a scalloped or otherwise undulating fashion. Nonetheless, the orientations of the different regions (e.g., regions 310, 320, 330, and 340) of the cutting profile 305 relative to each other and the bit axis 204 may be described in general or approximate terms. For example, the cone region 310 may be substantially perpendicular to the bit axis 204. That is, whether the cone region 310 is scalloped, concave, convex, or otherwise non-linear, a best-fit linear approximation 312 (depicted in FIG. 3 by a dashed line) of the cone region 310 may be angularly offset from the bit axis 204 by an amount ranging between eighty degrees (80°) and one hundred degrees (100°).

Such convention may also be utilized to describe the shoulder region 330 as being substantially perpendicular to the cone region 310 and/or the bit axis 204. For example, although the shoulder region 330 may be non-linear, a best-fit linear approximation 332 (depicted in FIG. 3 by a dashed line) of the shoulder region 330 may be angularly offset from the best-fit linear approximation 312 of the cone region 310 by an amount ranging between eighty degrees (80°) and one hundred degrees (100°). The best-fit linear approximation 332 of the shoulder region 330 may also or instead be substantially parallel to the bit axis 204. For example, the best-fit linear approximation 332 of the shoulder region 330 may be angularly offset from the bit axis 204 by less than ten degrees (10°). The gage region 340 may similarly be described as being substantially parallel to the bit axis 204 and/or substantially perpendicular to the cone region 310. That is, although the gage region 340 may be non-linear, a best-fit linear approximation of the gage region 340 may be angularly offset from the bit axis 204 by less than ten degrees (10°) or offset from the cone region 310 by an amount ranging between eighty degrees (80°) and one hundred degrees (100°). In other embodiments, however, angular offsets between the cone region 310, shoulder region 330, and gage region 340 may be more than ten degrees) (10° from being parallel or perpendicular to each other, or relative to the bit axis 204.

The nose region 320 may extend along a portion of the cutting profile 305 aligned with the outermost edge 258 of the larger cutting element 250, and between intersections with the outer edges 256 of the opposing smaller cutting elements 252. In some embodiments, the nose region 320 and the cutting element 250 may be co-radial, having the same radius 322 and the same center point 324. In some implementations, the outermost edges 258 of multiple instances of the larger cutting element 250 (e.g., carried by different ones of the primary blades 230, 232, and 234 of FIG. 2) may collectively define the nose region 320. The multiple instances of the larger cutting element 250 may have the same radial and axial position on each blade, such that the nose region 320 is co-radial with each of the larger cutting elements 250.

In the example implementation depicted in FIGS. 2 and 3, the outermost extents 256 of each cutting element 252 that doesn't define the cone region 310 of the cutting profile 305 may collectively define the shoulder region 330 and the gage region 340, or at least a substantial portion thereof. The primary blades 230, 232, and 234 and/or the secondary blades 240, 242, and 244 may carry the cutting elements 252 whose outermost extents 256 define the shoulder region 330 and/or gage region 340. The one or more primary blades 230, 232, and 234 that carry the larger cutting element 250 may not carry the cutting elements 252 that are closest to the nose region 320. Instead, the secondary blades 240, 242, and 244, and/or one or more of the primary blades 230, 232, and 234 that do not carry the larger cutting element 250, may carry the cutting elements 252 that are closest to the nose region 320.

As shown in the example implementation depicted in FIG. 3, one or more channels 360 may also extend between an interior passage 370 or bore of the bit 200 and outlet ports 380 on the bit face 220. Accordingly, fluid (e.g., drilling fluid) pumped to the bit 200 from the wellsite may exit the outlet ports 380 via the channels 360 to lubricate the bit 200 and subsequently carry any cuttings back to the surface.

FIG. 4 is a schematic view of another bit 400 shown in a rotationally aggregated profile view, with cutting elements 250 and 252 collectively defining a cutting profile 405. Features of the bit 400, other than the cutting elements 250 and 252 and the cutting profile 405, are not shown in FIG. 4, although merely for the sake of clarity, as those skilled in the art will readily understand with the benefit of the present disclosure that features and/or other aspects of other bits (e.g., the bit 200 of FIGS. 2 and 3) may be included, applicable, or readily adapted for utilization in the bit 400 shown in FIG. 4.

The cutting profile 405 may comprise a cone region 410, a nose region 420, and a gage region 440, with each being generally defined in the same manner as similar regions are described above with respect to FIG. 3. The portion of the outermost extent 258 of the larger cutting element 250 that partially defines the cutting profile 405 may define the nose region 420, or at least a substantial portion thereof (as described herein), and in some embodiments the nose region 420 of the cutting profile 405 and the cutting element 250 may have substantially the same radius 422 and perhaps the same center point 424. Thus, the nose region 420 and the cutting element 250 may be co-radial in some embodiments. However, in other embodiments within the scope of the present disclosure, the tips, edges, or outer extents of additional cutting elements may define a portion of the nose region 420. For example, the outermost extent of multiple instances of the larger cutting element 250 (carried by different ones of the primary blades) may define the nose region 420, or at least a portion thereof. In other embodiments, the nose region 420 may be at least partially defined by one or more of the smaller cutting elements 252.

The cutting element 250 may be considered to “substantially define” the nose region 420 when the cutting element 250 makes up at least seventy-five percent (75%) of length of the nose region 420, with the remainder of the nose region 420 including one or more of the cutting elements 250 and/or 252 in a different radial and/or axial position on the bit 400. In some embodiments, the larger cutting element 250 may “substantially define” the nose region 420 when the larger cutting element 250 makes up at least ninety percent (90%) of the nose region 420, with the remainder of the nose region 420 including one or more of the smaller cutting elements 252 or other larger cutting elements 250 in a different radial and/or axial position on the bit 400. In some embodiments, however, the nose region 420 may not be defined by cutting elements other than one or more instances of the larger cutting element 250 (e.g., each on a different blade). The nose region 420 may also be considered to have a radius “substantially equal” to the radius of the cutting element 250 when the radius of the cutting element 250 is within at least twenty percent (20%) of the radius of the nose region 420.

In the example implementation depicted in FIG. 4, the outermost extents 256 of the cutting elements 252 that don't define the cone region 410 of the cutting profile 405 may collectively define the gage region 440 of the cutting profile 405. The cutting elements 252 whose outermost extents 256 define the cone region 410 and/or the gage region 440 of the cutting profile 405 may be carried by multiple ones of the primary and the secondary blades of the bit 400, and those that are closest to the nose region 420 of the cutting profile 405 may not be carried by the primary blades that carry instances of the larger cutting element 250.

In the example implementation shown in FIG. 4, the outermost extents 256 of two (2) cutting elements 252 may define the cone region 410 of the cutting profile 405, and the outermost extents 256 of at least three (3) cutting elements 252 may define the gage region 440. These numbers may, however, vary in other implementations within the scope of the present disclosure. Optionally, the larger cutting element 250 may have a diameter of thirteen (13) millimeters, and the smaller cutting elements 252 may have a diameter of nine (9) millimeters, although other dimensions are also within the scope of the present disclosure, including those set forth in Table 1 above, among others.

FIG. 5 is a schematic view of another bit 500, with cutting elements 250 and 252 shown in a rotationally aggregated, profile view defining a cutting profile 505. Features of the bit 500, other than the cutting elements 250 and 252 and the cutting profile 505, are not shown in FIG. 5, although merely for the sake of clarity, as those skilled in the art will readily understand in view of the present disclosure that features and/or other aspects of other bits (e.g., the bits shown in FIGS. 2, 3, and 4) may be included, applicable, or readily adapted for utilization in the bit 500 shown in FIG. 5.

The cutting profile 505 may comprise a cone region 510, a nose region 520, and a gage region 540 in some embodiments. A continuous portion of the outermost extent 258 of the cutting element 250 that partially defines the cutting profile 505 may define the nose region 520, or at least a substantial portion thereof, in a manner similar to as described above with respect to FIGS. 3 and 4. In some implementations, the nose region 520 of the cutting profile 505 and the cutting element 250 may have the substantially the same radius 522 and perhaps the same center point 524, and thus be co-radial. However, in other implementations within the scope of the present disclosure, the outermost extents of additional cutting elements 250 and 252 may define a portion of the nose region 520. For example, multiple blades may each have a cutting element 250 coupled thereto at a same radial and axial position, so that the multiple instances of the cutting element 250 may define the nose region 520, or at least a portion thereof. In some embodiments, multiple cutting elements 250 may have different radial and/or axial positions, but may nonetheless collectively define the nose region 520, or at least a portion thereof. In still other embodiments, one or more cutting elements 252 may be positioned to define at least a portion of the nose region 520.

In the example implementation depicted in FIG. 5, the outermost extents 256 of the cutting elements 252 that don't define the cone region 510 of the cutting profile 505 may collectively define the gage region 540 of the cutting profile 505, or at least a substantial portion thereof, in a manner similar to as described herein. The cutting elements 252 whose outermost extents 256 define the gage region 540 and/or the cone region 510 of the cutting profile 505 may be carried by multiple ones of the blades of the bit 500 (e.g., one or more primary and/or secondary blades). In some implementations, the same blade that carries a larger cutting element 250 may not carry the cutting elements 252 that are positioned closest to the nose region 520 of the cutting profile 505.

In the example implementation shown in FIG. 5, the outermost extents 256 of at least twelve (12) cutting elements 252 may define the cone region 510 of the cutting profile 505, and the outermost extents 256 of at least six (6) cutting elements 252 may define the gage region 540. These numbers may, however, vary in other implementations within the scope of the present disclosure. For example, the outermost extents 256 of as few as two (2) cutting elements 252, or as many as thirty (30) cutting elements 252, may define the cone region 510 and/or the gage region 540. The larger cutting element 250 may have a diameter of twenty-two (22) millimeters, and the smaller cutting elements 252 may have a diameter of thirteen (13) millimeters, although other dimensions are also within the scope of the present disclosure, including those listed in Table 1, among others.

The number of primary and secondary blades of a bit may also vary within the scope of the present disclosure. For example, FIG. 6 is a perspective view of a portion of another example implementation of a bit 600. The illustrated bit 600 includes two primary blades 620 and 622 and two secondary blades 630 and 632. Drilling fluid flow courses, or junk slots 662, may separate the primary blades 620 and 622 and the secondary blades 630 and 632.

The distal or downhole ends of the primary blades 620 and 622 may be closer to the central axis of the bit 600 than are the distal or downhole ends of the secondary blades 630 and 632. Implementations within the scope of the present disclosure may also include bits with no primary blades, such that each blade terminates at a distance from the central axis and/or a distal or downhole end of the bit 600. Other implementations within the scope of the present disclosure may also include bits with no secondary blades, such that each blade terminates at or near the central axis and/or a distal or downhole end of the bit 600. The number of primary and secondary blades may also vary within the scope of the present disclosure, from as few as zero (0) or one (1) of either type of blade, to as many as four (4), eight (8) or ten (10) of either type of blade.

As with other example implementations described herein, the cutting elements 250 and 252 may be mounted in pockets formed in, or coupled to, the primary blades 620 and 622 and the secondary blades 630 and 632, although other techniques for coupling the cutting elements to the bit 600 are also within the scope of the present disclosure. As discussed herein, some embodiments contemplate the cutting element 250 as being between fifteen (15%) and three hundred percent (300%) larger than the cutting elements 252 in diameter, or between one (1) and four (4) industry-standard sizes larger. The dimensions of the cutting elements 250 and 252 may, however, vary within the scope of the present disclosure, including as set forth in Table 1, among others. For instance, in other embodiments, the cutting elements 250 may be more less than fifteen percent (15%), or more than three hundred percent (300%) larger than the cutting elements 252, or the cutting elements 250 may be more than four (4) industry-standard sizes larger than the cutting elements 252.

FIG. 7 is a perspective view of a portion of another bit 700 according to some embodiments of the present disclosure. Features other than the cutting elements 250 and 252 are not shown in FIG. 7, although merely for the sake of clarity, as those skilled in the art will readily understand in view of the present disclosure that features and/or other aspects of other bits (e.g., the bits shown in one or more of FIGS. 2-6) may be included, applicable, or readily adapted for utilization in the bit 700 shown in FIG. 7.

The bit 700 may include multiple instances of a larger cutting element 250. In such implementations, the larger cutting elements 250 may be carried by different ones of the blades (e.g., different primary blades, different secondary blades, or a combination of primary and secondary blades). Where the larger cutting elements 250 are each carried by a different primary blade, each may be positioned relative to the corresponding primary blade such that the nose region of the resulting cutting profile is collectively defined by outermost extents of the larger cutting elements 250. For example, the positions of the multiple instances of the larger cutting elements 250 may have substantially the same radial coordinates (relative to radial axis 701) and/or the same axial coordinates (relative to bit axis 204), but may have different azimuth coordinates (e.g., due to being carried by different blades). In other embodiments, the multiple instances of the larger cutting elements 250 may have different radial and axial coordinates, but nonetheless still collectively define the nose region of the resulting cutting profile.

FIG. 7 also demonstrates that the cutting elements 250 and 252 may have varying back rake and/or side rake within an implementation having one or more aspects of the present disclosure. Side rake and back rake may be more easily explained with respect to FIG. 8.

FIG. 8 is a schematic view of a portion of a bit 800, and illustrates cutting elements 811-815, 821, 822, and 841-845 rotated into an aggregated profile view and defining a cutting profile 805. Features other than the cutting elements and the cutting profile 805 are not shown in FIG. 8, although merely for the sake of clarity, as those skilled in the art will readily understand in view of the present disclosure that features and/or other aspects of other bits, including bits described or illustrated herein, may be included, applicable, or readily adapted for utilization in the bit 800 shown in FIG. 8.

A cone region 810 of the cutting profile 805 may include cutting elements 811-815, which may each be substantially similar to the cutting elements 252 described herein or shown in FIGS. 2-7. Multiple instances of one or more of the cutting elements 811-815 may also be included on different blades. In particular, cutting elements on different blades may have the same axial and radial position so as to appear as a single cutting element 811-815 in FIG. 8. In some embodiments of the present disclosure, the radially inner cutting element 811 and the radially outer cutting element 815 of the cone region 810 may have substantially no back rake and/or substantially no side rake. Thus, in the profile view of FIG. 8, the cutting elements 811 and 815 appear substantially round. A medial cutting element 813 may have side rake, or rotation around an axis 853 that is substantially normal to the adjacent portion of the cutting profile 805. Such rotation may be either clockwise or counterclockwise. As a result, the medial cutting element 813 may appear elongated in a direction that is substantially normal to the adjacent portion of the cutting profile 805, although the medial cutting element 813 may have substantially the same shape as the inner and outer cutting elements 811 and 815.

Similarly, the intermediate cutting element 812 may have back rake, or rotation around an axis 862 that may be substantially parallel to the adjacent cone portion 810 of the cutting profile 805. An intermediate cutting element 814 may also exhibit back rake, or rotation around an axis 864 that may be substantially parallel to the adjacent cone region 810 of the cutting profile 805. As a result, the intermediate cutting elements 812 and 814 appear in FIG. 8 to be elongated in a direction substantially parallel to the adjacent cone region 810 of the cutting profile 805, although they each may have substantially the same shape as the inner cutting element 811, the middle cutting element 813, the outer cutting element 815, or some combination of the foregoing.

The back rake of the intermediate cutting elements 812 and 814 may be either positive back rake or negative back rake. That is, if the cutting face of the cutting element 812 and 814 and the surface of the formation or material being cut (e.g., subterranean formation, casing, cement, scale, downhole tools, etc.) form an angle that is greater than ninety degrees (90°), then that cutting element exhibits positive back rake; whereas, if the angle is less than ninety degrees (90°), then that cutting element exhibits negative back rake. Thus, if the angle is substantially equal to ninety degrees (90°), then the cutting element would be exhibiting substantially no back rake.

As shown in FIG. 8, a gage region 840 of a cutting profile 805 may include cutting elements 841-845, one or more of which may be substantially similar to the cutting elements 811-815, or other cutting elements 252 described herein or illustrated herein. Multiple instances of one or more of the cutting elements 841-845 may also be included on different blades. The cutting element 841 is shown as being closest to the nose region 820 of the cutting profile 805, and along with cutting element 844 may have substantially no back rake and substantially no side rake. Thus, in the profile view of FIG. 8, the cutting elements 841 and 844 appear substantially round. In contrast, cutting elements 842 and 845 may exhibit side rake, or rotation around an axis that is substantially normal to the adjacent gage portion 840 of the cutting profile 805. Such rotation may be either clockwise or counterclockwise. As a result, the cutting elements 842 and 845 appear in FIG. 8 to be elongated in a direction that is normal or orthogonal to the adjacent gage region 840 of the cutting profile 805, although they may have substantially the same shape as the cutting elements 841 and 844.

Similarly, the cutting element 843 may exhibit back rake, or rotation around an axis that is substantially parallel to the adjacent gage region 840 of the cutting profile 805. As a result, the cutting element 843 appears in FIG. 8 to be elongated in a direction parallel to the gage region 840 of the cutting profile 805, although the cutting element 843 may have substantially the same shape as the cutting elements 841, 842, 844, and 845.

The nose region 820 of the example cutting profile 805 depicted in FIG. 8 may include cutting elements 821 and 822. The cutting elements 821 and 822 may be larger than one or more of the cutting elements 811-815 and 841-845. As described herein, implementations within the scope of the present disclosure may include multiple instances of smaller and/or larger cutting elements. Multiple instances of larger cutting elements may substantially define the nose region of the resulting cutting profile, in the manner described herein. Multiple instances of larger cutting elements may be positioned at substantially the same axial and radial coordinates yet differ in azimuth coordinates because they are carried by different blades. The multiple larger cutting elements may also differ with respect to back rake and/or side rake. Thus, while the larger cutting elements 821 and 822 in the nose region 820 may each have substantially circular cutting faces, they appear to be elongated in FIG. 8 as the result of back rake and/or side rake as described herein. As with the smaller cutting elements 811-815 and 841-845, the larger cutting elements 821 and 822 may exhibit substantially the same or different back rake, whether positive or negative, and/or may exhibit substantially the same or different side rake, whether clockwise or counterclockwise.

FIG. 9 is a flow-chart diagram of at least a portion of a bit design process (900) according to one or more aspects of the present disclosure. The process (900) may be utilized to design and produce the bit 200 shown in FIGS. 2 and 3, the bit 400 shown in FIG. 4, the bit 500 shown in FIG. 5, the bit 600 shown in FIG. 6, the bit 700 shown in FIG. 7, the bit 800 shown in FIG. 8, or other bits within the scope of the present disclosure.

In a conventional bit design process, a bit profile may generally be determined or designed, and the cutting elements may then be arranged to generally obtain the designed profile. Each cutting element is typically the same size, and that size is also determined by arranging the cutting elements in a manner that will obtain the desired profile. By utilizing a cutting element in the nose region that is larger relative to cutting elements in cone, shoulder, or gage regions, a cutting profile according to embodiments of the present disclosure can effectively be designed in reverse, such as by first selecting a cutting element for the nose region and then creating a profile with the nose region of the size defined by the selected cutting element.

For example, in the example process (900) shown in FIG. 9, a first cutting element may be selected (910). As discussed herein, cutting elements used in a bit may be selected from a set of industry-standard sizes, or custom sizes may be used. Accordingly, selecting the first cutting element may include selecting the type of the first cutting element (e.g., the size, materials, shape, and the like). In accordance with some embodiments of the present disclosure, the first cutting element may be used for the nose region of a cutting profile, and the process (900) may therefore also include defining a cutting profile and setting the radius of a nose region to be substantially equal to and/or co-radial with the radius of the selected first cutting element (920). Defining the cutting profile (920) may therefore also include arranging the first cutting element (or multiple first cutting elements) on a bit so as to be positioned co-radial with, or to otherwise substantially define the radius of the nose region. When arranging the first cutting element on the bit, the first cutting element may be placed at a single location, or at multiple locations (e.g., at similar radial/axial positions but at different azimuths corresponding to different blades).

In some embodiments, the defined cutting profile may include one or more additional regions in addition to the nose region. Defining the cutting profile (920) may therefore also include defining multiple regions of the cutting profile (e.g., cone region, shoulder region, gage region, etc.). In some embodiments, the defined cutting profile may include linear, arcuate, or other cone, shoulder, gage, or other regions, rather than a cutting profile with scalloped or undulating regions. Additional types of cutting elements may then be selected and arranged to generally follow or approximate the designed cutting profile (e.g., with a best-fit line approximation closely matching the designed profile). To that end, the example process (900) may further include selecting the type of second cutting elements (930) (e.g., size, materials, shape, and the like) and arranging the second cutting elements to match the gage, shoulder, cone region, or other regions of the profile (940). Selecting the type of the second cutting elements (930) may include selecting cutting elements that are smaller than the first cutting element and/or selecting multiple sizes of cutting elements. In some embodiments, sizing the second cutting elements (930) and arranging the second cutting elements (940) may be an iterative process. Optionally, the second cutting elements may be at least two (2) industry standard sizes smaller than the first cutting elements. In other embodiments, however, the first and second cutting elements may be the same size, may be one industry standard size different, or may otherwise differ, including in manners discussed herein.

As discussed herein, cutting elements may be placed on multiple blades of a bit so as to collectively define the cutting profile. As seen with respect to FIG. 8, for instance, different cutting elements may overlap to define the cutting profile. As will be appreciated in view of the present disclosure, such overlap may be due to the rotationally aggregated view of the profile, and may not include actually placing overlapping cutting elements on the same blade. Rather, cutting elements which overlap (e.g., cutting elements 822, 841, and 842 of FIG. 8) may each be arranged on different blades (and at different azimuths) but at the axial and radial positions corresponding to the cutting profile. Arranging the cutting elements (940) may therefore be performed in three-dimensional space. Additional factors may also be considered when arranging the cutting elements. For instance, spacing between different cutting elements on the same blade may be considered to ensure that a blade can be formed to provide sufficient material to hold a cutting element in a corresponding pocket, or sufficient space for another attachment mechanism to be used.

In accordance with some embodiments of the present disclosure, the example process (900) may be implemented using a computing system. For instance, a cutting profile may be defined (920) using a software application executed by one or more processors of a computing system. The shape and other characteristics of the cutting profile may be stored in memory and/or persistent storage. First and second cutting elements may also be defined through use of the software application and manipulated and moved in three-dimensions to define the cutting profile. This may also include defining size, shape, orientation, and number of blades which support the cutting elements. The three-dimensional arrangement of the cutting elements and the blades may therefore also be saved by or using the computing system.

In some embodiments, the computing system may also be used to simulate use of the bit. For instance, a simulation may be run for a designed drill bit when drilling through a particular type of formation. A similar simulation may be run for a milling bit when milling through casing to form a window, when milling out a bridge plug, or the like. A simulation may also be run for an underreamer block defined using a process similar to that described above, when expanding a wellbore diameter.

Simulations of different designs may also allow for comparisons and iterative modeling. For instance, in a scaling operation, the scale forms from the outside in, and the nose region of the bit may be in contact with the most scale as it may even contact scale at depths having minimal scale formation. The nose region may, in some embodiments, be more vulnerable to damage, delamination, or other mechanical failures resulting from impact forces, shear forces, higher temperatures, shear forces. A simulation system may simulate these conditions, and bits designed in accordance with embodiments of the present disclosure may be simulated to compare effectiveness in removing scale, resistance to damage, and the like. In some embodiments, a simulation or actual run of a bit designed in accordance with embodiments of the present disclosure may show significant resistance to damage as compared to a bit having smaller cutting elements in a nose region or which uses multiple cutting elements to define the nose region. For instance, utilizing larger cutters at the nose may improve heat dissipation and/or otherwise provide greater stability, which may reduce delamination at or near the nose region. Of course, similar simulations, comparisons, and results may be obtained for other types of drilling, milling, underreaming, or other operations, and simulated and actual results of newly designed bits may be compared against other existing or newly developed bits.

Accordingly, some embodiments of the present disclosure relate to bits and other cutting tools that may include a bit body having multiple blades extending therefrom. Each of a plurality of first cutting elements may be on, in, or otherwise coupled to a corresponding one of the blades. One or more second cutting elements may also be coupled to the plurality of blades and may, with the first cutting elements, define a cutting profile. The second cutting elements may substantially define the nose region of the cutting profile and may be substantially larger than the first cutting elements.

In some embodiments, outer extents of the first and second cutting elements, relative to the bit body and/or axis of the bit body, may define the cutting profile. Further, some embodiments contemplate first and/or second cutting elements each including a substrate and a diamond layer. In some implementations, one or more first and/or second cutting elements may have a back rake or a side rake.

In accordance with at least some embodiments, second cutting elements substantially defining the nose region may define at least 75% of the nose region, or even 90%. Optionally, the second cutting elements may define the full nose region exclusive of the first cutting elements. At least some embodiments contemplate at least two second cutting elements coupled to the blades and located in the nose region. The two second cutting elements may be positioned at the same axial and radial positions, but on different blades extending azimuthally from the bit body.

Cutting elements may have different respective sizes. In some embodiments, the second cutting elements may be at least four (4) millimeters larger than the first cutting elements. In another embodiment, the cutting elements may be industry-standard sizes, and there may be two (2) industry-standard sizes difference between the first and second cutting elements. Optionally, the second cutting element has a diameter within a range having lower and/or upper limits that include any of 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 100%, 110%, 125%, 150%, 200%, 250%, or 300% the diameter of the first cutting elements, or any value therebetween. In some embodiments, the diameter of the second cutting element may be substantially larger than each first cutting element outside the nose region.

According to another embodiment of the present disclosure, an apparatus may include a bit body with multiple blades coupled thereto. A plurality of cutting elements may be coupled to the blades and may define a cutting profile having cone, nose, and gage regions. The cone region may be nearest a central axis of the body, and the gage region may be furthest from the central axis, with the nose region therebetween. A radius of the nose region may be substantially equal to a radius of at least one first cutting element. The cone and gage regions may each include one or more second cutting elements of a diameter different than the diameter of the first cutting element.

In some embodiments, the nose region may be substantially co-axial with a first cutting element. The nose region may also have an outer extent substantially defining the nose region. Optionally, the first cutting elements may be three (3) or four (4) or more millimeters larger or smaller than the second cutting elements. In one embodiment, the first and second cutting elements may differ by at least two (2) industry-standard sizes. In a particular embodiment, the first cutting elements may be between 15% and 300% larger in diameter than second cutting elements. In at least one embodiment, the second cutting elements are all the same size.

In at least one particular embodiment, two or more cutting elements may have the same radial and axial positions on separate blades. Such cutting elements may be located in the nose, cone, shoulder, gage, or other region of a cutting profile. Further, two or more cutting elements may have differing back rake or side rake in some embodiments.

Other embodiments herein may relate to a method for dislodging material in a wellbore. An example may include moving or otherwise urging a bit toward a downhole end f a wellbore and dislodging material from the wellbore by rotating the bit. The bit may include cutting elements on blades to define a cutting profile as discussed herein. In some embodiments, the cutting elements in a nose region may have a different size as compared to cutting elements of other regions of the cutting profile and/or the cutting elements of the nose region may be co-radial with the nose region.

In some embodiments of a method for dislodging material in a wellbore, the dislodge material may include scale. In other embodiments, material from a subterranean formation may be removed. In other embodiments, casing, whipstocks, downhole tools, tubulars, bridge plugs, cement, or other materials may be dislodged.

Another embodiment of the present disclosure relates to designing a bit. In designing the bit, a first size of cutting element may be selected. After selecting the first size, a cutting profile can be created with a nose region and one or more other regions. The nose region may be created to have a radius substantially equal to a radius of the cutting element of the first size. A second size for multiple cutting elements may be selected and different (i.e., smaller or larger) than the first size. The first and second sizes of cutting elements can be arranged on multiple blades of the bit with the cutting profile, and the first sized cutting elements may be co-radial with the nose region while the second cutting elements are arranged in other regions of the cutting profile.

In some embodiments, creating the arrangement may include overlapping cutting elements. A cutting element of the second size may be overlapped with a cutting element of the first size. Overlapping cutting elements may be positioned on different blades. Where multiple cutting elements of a first size are included, such cutting elements may each be on a different blade. The different blades may each be primary blades, each be secondary blades, or a combination of primary and secondary blades.

According to some embodiments, designing a bit may include using a software application to design the bit in three-dimensions. First and second cutting elements may be arranged in three-dimensions along multiple blades. A design of the cutting elements may be stored in persistent storage or memory. The design may be used to simulate operation of the blade and/or to manufacture a bit. Designing a bit may also include positioning cutting elements on a physical bit.

In the description herein, various relational terms are provided to facilitate an understanding of various aspects of some embodiments of the present disclosure. Relational terms such as “bottom,” “below,” “lower, “top,” “above,” “upper”, “back,” “front,” “rear”, “left”, “right”, “forward”, “up”, “down”, “horizontal”, “vertical”, “inner”, “outer”, “clockwise”, “counterclockwise,” and the like, may be used to describe various components, including their operation and/or illustrated position relative to one or more other components. Relational terms do not indicate a particular orientation for each embodiment within the scope of the description or claims. For example, a component of a BHA that is “below” another component may be more downhole while within a primary or vertical wellbore, but may have a different orientation during assembly, when removed from the wellbore, or in a deviated borehole. Accordingly, relational descriptions are intended solely for convenience in facilitating reference to various components, but such relational aspects may be reversed, flipped, rotated, moved in space, or similarly modified. Relational terms may also be used to differentiate between similar components. Certain descriptions or designations of components as “first,” “second,” “third,” and the like may also be used to differentiate between similar components. Such language is not intended to limit a component to a singular designation. As such, a component referenced in the specification as the “first” component may be the same or different than a component that is referenced in the claims as a “first” component.

Furthermore, to the extent the description or claims refer to “an additional” or “other” element, feature, aspect, component, or the like, it does not preclude there being a single element, or more than one, of the additional element. Where the claims or description refer to “a” or “an” element, such reference is not be construed that there is just one of that element, but is instead to be inclusive of other components and understood as “one or more” of the element. It is to be understood that where the specification states that a component, feature, structure, function, or characteristic “may,” “might,” “can,” or “could” be included, that particular component, feature, structure, or characteristic is provided in some embodiments, but is optional for other embodiments of the present disclosure. The terms “couple,” “coupled,” “connect,” “connection,” “connected,” “in connection with,” and “connecting” refer to “in direct connection with,” “integral with,” or “in connection with via one or more intermediate elements or members.”

Although various example embodiments have been described in detail herein, those skilled in the art will readily appreciate in view of the present disclosure that many modifications are possible in the example embodiments without materially departing from the present disclosure. A person having ordinary skill in the art should realize in view of the present disclosure that equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alterations may be made to embodiments disclosed herein without departing from the spirit and scope of the present disclosure. Accordingly, any such modifications are intended to be included in the scope of this disclosure. Each addition, deletion, and modification to the embodiments that falls within the meaning and scope of the claims is to be embraced by the claims. While the disclosure herein contains many specifics, these specifics should not be construed as limiting the scope of the disclosure or of any of the appended claims, but merely as providing information pertinent to one or more specific embodiments that may fall within the scope of the disclosure and the appended claims. Any described features from the various embodiments disclosed may be employed in combination.

While embodiments disclosed herein may be used in an oil, gas, or other hydrocarbon exploration or production environment, such environments merely illustrate example environments in which embodiments of the present disclosure may be used. Systems, tools, assemblies, apparatuses, methods, and other components discussed herein, or which would be appreciated in view of the disclosure herein, may be used in other applications and environments, including in automotive, aquatic, aerospace, hydroelectric, or even other downhole environments. The terms “wellbore,” “borehole,” and the like are therefore also not intended to limit embodiments of the present disclosure to a particular industry. A wellbore or borehole may, for instance, be used for oil and gas production and exploration, water production and exploration, mining, utility line placement, or myriad other applications.

Certain embodiments and features may have been described or claimed using a set of values defining lower and/or upper limits. It should be appreciated that ranges including the combination of any two values are contemplated; however, each value is also contemplated as defining an upper limit (e.g., at least 50%) or lower limit (e.g., up to 50%). Endpoints of a range are intended to be included unless expressly disclaimed. Any numerical value is “about” or “approximately” the indicated value (e.g., the expressions “thirteen (13) millimeters” and “three hundred percent (300%)” are equivalent to the expressions “about thirteen (13) millimeters” and “about three hundred percent (300%),” respectively), and takes into account experimental error, manufacturing tolerances, standardized sizing, and other variations that would be expected by a person having ordinary skill in the art.

The Abstract at the end of this disclosure is provided to allow the reader to quickly ascertain the general nature of some embodiments of the present disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Claims

1. A cutting tool, comprising:

a bit body;

a plurality of blades extending from the bit body;

a plurality of first cutting elements each coupled to a corresponding one of the plurality of blades; and

a second cutting element coupled to one of the plurality of blades and defining with the plurality of first cutting elements a cutting profile, the second cutting element substantially defining a nose region of the cutting profile and being substantially larger than at least one of the plurality of first cutting elements.

2. The cutting tool of claim 1, the plurality of first cutting elements and the second cutting element each including a substrate and a diamond layer, and at least one of the plurality of first cutting elements or the second cutting element exhibiting at least one of a back rake or a side rake.

3. The cutting tool of claim 1, the second cutting element defining at least 75% of the nose region.

4. The cutting tool of claim 1, the second cutting element defining at least 90% of the nose region.

5. The cutting tool of claim 1, the nose region being defined by the second cutting element exclusive of the plurality of first cutting elements.

6. The cutting tool of claim 1, further comprising:

an additional second cutting element coupled to one of the plurality of blades and located in the nose region.

7. The cutting tool of claim 6, the second cutting element and the additional second cutting element being positioned at same axial and radial positions on different ones of the plurality of blades.

8. The cutting tool of claim 1, the second cutting element being one or more of:

at least four (4) millimeters larger than the at least one of the plurality of first cutting elements;

at least two (2) industry-standard sizes larger than the at least one of the plurality of first cutting elements; or

between 15% and 300% larger in diameter than the at least one of the plurality of first cutting elements.

9. The cutting tool of claim 1, the second cutting element having a diameter substantially larger than a diameter of each of the plurality of first cutting elements positioned outside the nose region.

10. An apparatus, comprising:

a bit body;

a plurality of blades coupled to the bit body; and

a plurality of cutting elements each coupled to a corresponding one of the plurality of blades, the plurality of cutting elements defining a cutting profile having: a cone region nearest a central axis of the bit body; a gage region furthest from the central axis; and a nose region between the cone region and the gage region, the nose region having a radius substantially equal to a radius of at least one first cutting element of the plurality of cutting elements, and the cone region and the gage region each including at least one second cutting element of the plurality of cutting elements that has a different size, shape, or construction than the at least one first cutting element.

11. The apparatus of claim 10, the nose region being substantially co-axial with the at least one first cutting element.

12. The apparatus of claim 10, the at least one first cutting element having an outer extent substantially defining the nose region.

13. The apparatus of claim 10, each of at least one first cutting elements being one or more of:

at least four (4) millimeters different in diameter than each of the at least one second cutting elements;

between 15% and 300% larger in diameter than each of the at least one second cutting elements; or

at least two (2) industry-standard sizes different than each of the at least one second cutting elements.

14. The apparatus of claim 10, at least two of the plurality of cutting elements having same radial and axial positions on separate ones of the plurality of blades.

15. The apparatus of claim 10, at least two of the plurality of cutting elements having differing back rake or side rake.

16. The apparatus of claim 10, each of the plurality cutting elements, except for the at least one first cutting element, being of a same size.

17. A method, comprising:

urging a bit toward a downhole end of a wellbore, the bit comprising a plurality of cutting elements collectively defining a cutting profile having a nose region between cone and gage regions, a radius of the nose region equal to, and co-radial with, a first set of one or more of the plurality of cutting elements, and a second set of the plurality of cutting elements being positioned within the cone and gage regions and having a smaller diameter than the first set of one or more of the plurality of cutting elements; and

dislodging material from the wellbore by rotating the bit.

18. The method of claim 19, dislodging material from the wellbore including at least one of:

dislodging scale; or

dislodging subterranean formation.

19. The method of claim 19, the first set of the one or more of the plurality of cutting elements including more than one cutting element.

20. The method of claim 19, the second set of the plurality of cutting elements including more cutting elements than the first set of the one or more of the plurality of cutting elements.