Patent Grant
10392866
Cutting elements are traditionally utilized for a variety of material removal processes, such as machining, cutting, and drilling. For example, tungsten carbide cutting elements have been used for machining metals and on drilling tools for drilling subterranean formations. Similarly, polycrystalline diamond compact (PDC) cutters have been used to machine metals (e.g., non-ferrous metals) and on subterranean drilling tools, such as drill bits, reamers, core bits, and other drilling tools. Other types of cutting elements, such as ceramic (e.g., cubic boron nitride, silicon carbide, and the like) cutting elements, or cutting elements formed of other materials have also been utilized for cutting operations.
Drill bit bodies to which cutting elements are attached are often formed of steel or of molded tungsten carbide. Drill bit bodies formed of molded tungsten carbide (so-called matrix-type bit bodies) are typically fabricated by preparing a mold that embodies the inverse of the desired topographic features of the drill bit body to be formed. Tungsten carbide particles are then placed into the mold and a binder material, such as a metal including copper and tin, is melted or infiltrated into the tungsten carbide particles and solidified to form the drill bit body. Steel drill bit bodies, on the other hand, are typically fabricated by machining a piece of steel to form the desired external topographic features of the drill bit body.
In some situations, drill bits employing cutting elements may be used in mining environments to drill bolt holes in subterranean formations. Various types of cutting elements, such as PDC cutters, have been employed for drilling boreholes for subterranean support bolts. Although other configurations are known in the art, PDC cutters often comprise a substantially cylindrical or semi-cylindrical diamond “table” formed on and bonded under high-pressure and high-temperature (HPHT) conditions to a supporting substrate, such as a cemented tungsten carbide (WC) substrate.
Subterranean-bolt holes may accommodate support bolts, such as roof bolts, face bolts, or rib bolts, for securing subterranean formations. For example, in underground mining operations, such as coal mining, tunnels are formed underground. In order to make the tunnels safe for use, the roofs of the tunnels must be supported in order to reduce the chances of a roof cave-in and/or to block various debris falling from the roof. In order to support a roof in a mine tunnel, boreholes are typically drilled into the roof using a drilling apparatus. The drilling apparatus commonly includes a drill bit attached to a drilling rod (such as a drill steel). Roof bolts are inserted into the boreholes to secure a roof portion. In some situations, the roof bolts may be used to anchor a support panel or screen to the roof. Support bolts may also be utilized to secure other portions of a mining tunnel, such coal ribs/pillars, side faces, and floors.
Commonly, drilled boreholes may be filled with a resin prior to inserting the bolts, or the bolts may have self expanding portions, in order to anchor the bolts to the roof. Threaded bolts may be problematic to use for securing subterranean features due to their long lengths. Subterranean support bolts commonly extend to eight feet or more in order to adequately secure the formations. Driving a threaded bolt the entire length of a corresponding borehole would require a significant amount of time and energy. Alternatively, widening a portion of the borehole to accommodate a partially threaded bolt, such as a lag bolt, would require multiple drilling operations to be performed using different diameter drill bits in order to bore a single bolt hole, resulting in wasted time and resources.
Often, boreholes for support bolts, such as roof bolts, are drilled into a subterranean formation in a direction that is generally perpendicular to the surface of the formation. Alternatively, a borehole may be drilled at a non-perpendicular angle with respect to the formation surface. For example, a support bolt may extend at an angle through a portion of a coal rib and into an adjacent portion of the roof, thereby stabilizing the coal rib. Unfortunately, starting drilling of a borehole at an angle with respect to a subterranean surface is often difficult since the shape of the drill bit may cause the drill bit to “walk” or wander across the surface, rather than remaining centered at a desired point on the surface.
The instant disclosure is directed to exemplary roof-bolt drill bits. In some embodiments, a subterranean support-bolt drilling assembly may comprise a drill bit rotatable about a central axis, the drill bit having a forward end and a rearward end axially spaced away from the forward end, and the drill bit comprising at least one cutting edge. The drilling assembly may include a spacer coupled to the rearward end of the drill bit, the spacer extending axially rearward from the drill bit. In at least one embodiment, the spacer may have a length in the axial direction that is longer than the drill bit in the axial direction. The drilling assembly may also include a reamer member coupled to a rearward end of the spacer, the reamer member comprising at least one cutting element, the at least one cutting element comprising a cutting edge that extends radially beyond an outer peripheral portion of the drill bit relative to the central axis. The at least one cutting element may comprise a superabrasive material such as polycrystalline diamond.
According to at least one embodiment, the drill bit and the spacer may have a combined length of approximately 12 inches or more in the axial direction. A maximum diameter of the reamer member may exceed a maximum diameter of the drill bit by approximately 1 mm or more with respect to the central axis. In some embodiments, the drill bit may include at least one cutting element coupled to a bit body, the at least one cutting element of the drill bit comprising the at least one cutting edge of the drill bit. The at least one cutting element of the drill bit may be positioned adjacent the central axis such that the drill bit does not generate a core in a borehole created by the rotary drill bit during drilling.
A subterranean support-bolt drill bit may comprise a bit body rotatable about a central axis, the bit body having a forward end and a rearward end axially spaced away from the forward end, and at least one cutting element coupled to the bit body, the at least one cutting element comprising a cutting edge. The drill bit may also comprise a central pilot extending from the bit body in an axially forward direction, the central pilot comprising a cutting edge. The cutting edge of the at least one cutting element may extend radially beyond the central pilot relative to the central axis. The central pilot may also comprise at least one forward cutting element, the cutting edge of the central pilot including a portion of the at least one cutting element. The at least one forward cutting element may be axially spaced away from the forward end of the bit body. According to at least one embodiment, the central pilot may have a length of approximately 0.5 inches or more in the axial direction.
In some embodiments, the at least one forward cutting element may comprise a plurality of cutting elements spaced substantially equally about the central axis. According to additional embodiments, the at least one forward cutting element may comprise a single cutting element intersecting the central axis. The central pilot may be integrally formed with the bit body. The central pilot may be secured within a recess extending through at least a portion of the bit body. In some embodiments, at least a portion of the central pilot may have a generally cylindrical periphery. At least a portion of the central pilot may comprise a superabrasive material, such as polycrystalline diamond. At least a portion of the central pilot may additionally or alternatively comprise a carbide material. According to at least one embodiment, the drill bit may comprise a coupling shank extending generally parallel to the central axis. The central pilot may be connected to the coupling shank by a connection member extending through a hole defined in the bit body.
According to some embodiments, a subterranean support-bolt drilling assembly may comprise a drill steel and a drill bit mounted to the drill steel. The drill bit may comprise a bit body rotatable about a central axis, the bit body having a forward end and a rearward end axially spaced away from the forward end, and at least one cutting element coupled to the bit body, the at least one cutting element comprising a cutting edge. The drill bit may also comprise a central pilot extending from the bit body in an axially forward direction, the central pilot comprising a cutting edge, the cutting edge of the at least one cutting element extending radially beyond the central pilot relative to the central axis.
Features from any of the disclosed embodiments may be used in combination with one another in accordance with the general principles described herein. These and other embodiments, features, and advantages will be more fully understood upon reading the following detailed description in conjunction with the accompanying drawings and claims.
The accompanying drawings illustrate a number of exemplary embodiments and are a part of the specification. Together with the following description, these drawings demonstrate and explain various principles of the instant disclosure.
Throughout the drawings, identical reference characters and descriptions indicate similar, but not necessarily identical, elements. While the exemplary embodiments described herein are susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, the exemplary embodiments described herein are not intended to be limited to the particular forms disclosed. Rather, the instant disclosure covers all modifications, equivalents, and alternatives falling within the scope of the appended claims.
The instant disclosure is directed to exemplary rotary drill bits for drilling formations in various environments, including wet-drilling and dry-drilling environments. For example, a rotary drill bit may be coupled to a drill steel and rotated by a rotary drilling apparatus configured to rotate the rotary drill bit relative to a subterranean formation. The phrase “wet-drilling environment,” as used herein, may refer to drilling operations where drilling mud, water, and/or other drilling lubricants are supplied to a drill bit during cutting or drilling operation. In contrast, the phrase “dry-drilling environment,” as used herein, may refer to drilling operations that do not utilize drilling mud or other liquid lubricants during cutting or drilling operations. For ease of use, the word “cutting,” as used in this specification and claims, may refer broadly to machining processes, drilling processes, boring processes, or any other material removal process.
Drill bit 12 of drilling assembly 10 may comprise any type of drill bit suitable for drilling in wet-drilling environments and/or dry-drilling environments, without limitation. According to at least one embodiment, drill bit 12 may comprise a bit body 20 and at least one cutting element 22 coupled to bit body 20. As shown in
Spacer 14 may be coupled to drill bit 12. Spacer 14 may be centered about central axis 18 and may extend longitudinally along central axis 18. In some embodiments, spacer 14 may comprise a substantially elongated and/or cylindrical shaft. Spacer 14 may have a maximum diameter that is less than or approximately the same as a maximum diameter of drill bit 12.
Reamer member 16 may be coupled to spacer 14 at an end of spacer 14 that is axially opposite drill bit 12. Reamer member 16 may be centered about central axis 18. Reamer member 16 may include a reamer body 24 and at least one cutting element 26 coupled to reamer body 24. In some embodiments, reamer member 16 may also include a rearward coupling portion 28, which may include, for example, a shank extending along central axis 18.
In at least one embodiment, an internal passage 36 may be defined within bit body 20. As illustrated in
In some embodiments, bit body 20 may have a peripheral side surface 41 defining an outer periphery of bit body 20. In some examples, peripheral side surface 41 may comprise a generally cylindrical shape. Peripheral side surface 41 may also comprise any other suitable shape and/or configuration, without limitation. Peripheral side surface 41 may extend to a radial distance that is less than or approximately the same as outer portions of cutting elements 22, such as portions of the cutting edges. At least one debris channel 37 may be defined in bit body 20 to guide debris, such as rock cuttings, into internal passage 36. Debris channel 37 may be formed in a variety of shapes and sizes, such as the substantially concave shape illustrated in
The position and orientation of cutting elements 22 may facilitate drilling of a borehole as drill bit 12 is rotated during drilling of a subterranean formation. For example, cutting elements 22 may be positioned on drill bit 12 so that portions of cutting elements 22 (e.g., chamfer 72 illustrated in
Spacer 14 may comprise a substantially elongated and/or cylindrical shaft having a forward end 44 and a rearward end 46. Spacer 14 may also comprise any other suitable shape, without limitation. Spacer 14 may be configured to be temporarily or permanently coupled to drill bit 12 (e.g., by threaded connection, pin connection, mechanical attachment, brazing, welding, bonding, interference fit, and/or other suitable coupling). According to at least one embodiment, spacer 14 may include coupling surfaces corresponding to surfaces defined within drill bit 12. For example, spacer 14 may comprise a forward coupling projection 48 configured to fit within rearward opening 34 of drill bit 12. In some embodiments, forward coupling projection 48 may comprise a rounded, hexagonal, and/or threaded periphery corresponding to a rounded, hexagonal, and/or threaded interior surface defined within drill bit 12. In some embodiments, forward coupling projection 48 may comprise a pin connector corresponding to a pin hole and/or a recess defined within drill bit 20.
Spacer 14 may have a maximum diameter that is less than or approximately the same as a maximum diameter of drill bit 12. For example, a peripheral side surface 42 of spacer 14 may not extend radially beyond an outer peripheral portion of drill bit 12 relative to central axis 18. According to at least one embodiment, peripheral side surface 42 of spacer 14 may have substantially the same diameter as peripheral side surface 41 of bit body 20. In various embodiments, spacer 14 may have a length in the axial direction of central axis 18 that is longer than the length of drill bit 12 in the axial direction.
According to some embodiments, spacer 14 may comprise a hollow member configured to convey material toward and/or away from drill bit 12. For example, an internal passage may be defined in spacer 14 so as to extend from rearward opening 50 defined in rearward end 46 of spacer 14 to an opening defined in forward end 44 of spacer 14. Such a passage may be configured to convey a fluid, such as drilling fluid and/or air, through spacer 14 and toward drill bit 12. A passage defined within spacer 14 may also be configured to convey cutting debris, such as rock and/or carbonaceous debris, away from drill bit 12.
Reamer member 16 may be coupled to rearward end 46 of spacer 14 such that reamer member 16 is axially spaced away from drill bit 12. Reamer member 16 may be centered about central axis 18. Reamer member 16 may include a reamer body 24 and at least one cutting element 26 coupled to reamer body 24. In some embodiments, reamer member 16 may also include a rearward coupling portion 28, such as a shank, extending along central axis 18.
Reamer member 16 may have a forward end 52 and a rearward end 54 and may comprise any suitable shape, without limitation. Reamer member 16 may be configured to be temporarily or permanently coupled to drill bit 12 (e.g., by threaded connection, pin connection, mechanical attachment, brazing, welding, bonding, interference fit, and/or other suitable coupling). According to at least one embodiment, reamer member 16 may include coupling surfaces corresponding to surfaces defined within spacer 14. For example, reamer member 16 may comprise a forward coupling projection 58 configured to fit within rearward opening 50 of spacer 14. In some embodiments, forward coupling projection 58 may comprise a rounded, hexagonal, and/or threaded periphery corresponding to a rounded, hexagonal, and/or threaded interior surface defined within spacer 14. In some examples, forward coupling projection 58 may comprise a pin connector corresponding to a pin hole and/or a recess defined near rearward end 46 of spacer 14.
According to at least one embodiment, as shown in
Each cutting element 26 may comprise a cutting face 170 and a peripheral surface 175. Cutting face 170 and peripheral surface 175 may each be formed in any suitable shape and arranged in any suitable configuration, without limitation. Cutting elements 26 may be positioned on reamer member 16 in any suitable orientation, without limitation. For example, as illustrated in
Reamer member 16 may have a maximum diameter that is greater than a maximum diameter of drill bit 12. For example, portions of cutting elements 26 may extend radially beyond an outer peripheral portion of drill bit 12, including cutting edges of cutting elements 22, relative to central axis 18. According to at least one embodiment, a maximum diameter of reamer member 16 may exceed a maximum diameter of drill bit 12 by less than approximately 1 mm with respect to central axis 18. According to additional embodiments, a maximum diameter of reamer member 16 may exceed a maximum diameter of drill bit 12 by approximately 1 mm or more with respect to central axis 18. According to various embodiments, a maximum diameter of reamer member 16 may exceed a maximum diameter of drill bit 12 by between approximately 1 mm and approximately 2 mm, between approximately 2 mm and approximately 3 mm, between approximately 3 mm and approximately 4 mm, between approximately 4 mm and approximately 5 mm, or any other suitable amount, without limitation. By way of example, drill bit 12 may extend to a maximum diameter of approximately 22 mm with respect to central axis 18, and reamer member 16 may extend to a maximum diameter of approximately 24 mm with respect to central axis 18.
The position and orientation of cutting elements 26 may facilitate widening of a borehole as drilling assembly 10 is rotated during drilling. By way of example, cutting elements 26 may be positioned on reamer member 16 so that portions of each cutting element 26, such as chamfer 172, extend radially beyond peripheral side surface 56 of reamer member 16 relative to central axis 18. Accordingly, cutting elements 26 may contact a subterranean formation during drilling. Because cutting elements 26 extend radially beyond an outer peripheral portion of drill bit 12 relative to central axis 18, reamer member 16 may widen a portion of a borehole initially drilled by drill bit 12, as will be described in greater detail with reference to
According to some embodiments, reamer member 16 may comprise a hollow member configured to convey material toward and/or away from drill bit 12. For example, an internal passage may be defined in spacer 14 so as to extend from rearward opening 62 defined in rearward end 54 of reamer member 16 to a forward opening 53 defined in forward end 52 of reamer member 16. Such a passage may be configured to convey a fluid, such as drilling fluid and/or air, through reamer member 16 and toward spacer 14 and drill bit 12. A passage defined within reamer member 16 might also be configured to convey cutting debris, such as rock and/or carbonaceous debris, away from drill bit 12.
In various embodiments, rearward coupling portion 28 of reamer member 16 may comprise any shape suitable for coupling with and/or being driven rotationally about longitudinal axis 18 by a rotational member, such as a rotational drill chuck. For example, a cross-section of rearward coupling portion 28 may comprise an outer periphery having any suitable coupling and/or engagement shape, such as, for example, a generally geometric-shaped outer periphery, a generally polygonal-shaped outer periphery (e.g., a hexagonal or square shape), an uneven-shaped outer periphery, and/or a non-circular outer periphery, without limitation. In various embodiments, an exterior of rearward coupling portion 28 may comprise a threaded outer peripheral surface configured to be coupled with a drill chuck having a corresponding threaded inner surface.
Drill bit 12 and spacer 14 may have a combined length L1 in the axial direction along central axis 18 that is configured to form a narrow borehole portion during drilling for accommodating a portion of a subterranean support-bolt, such as a threaded portion of a support-bolt. According to at least one embodiment, drill bit 12 and the spacer 14 may have a combined length L1 of less than approximately 12 inches in the axial direction. According to additional embodiments, drill bit 12 and the spacer 14 may have a combined length L1 of approximately 12 or more in the axial direction. According to various embodiments, drill bit 12 and the spacer 14 may have a combined length L1 in the axial direction of between approximately 12 inches and approximately 13 inches, between approximately 13 inches and approximately 14 inches, between approximately 14 inches and approximately 15 inches, between approximately 15 inches and approximately 16 inches, between approximately 16 inches and approximately 17 inches, between approximately 17 inches and approximately 18 inches, between approximately 18 inches and approximately 19 inches, between approximately 19 inches and approximately 20 inches, or any other suitable length, without limitation.
For example, cutting element 22 may comprise a superhard PCD table 68 comprising polycrystalline diamond bonded to a substrate 67 comprising cobalt-cemented tungsten carbide. In at least one embodiment, after forming PCD table 68, a catalyst material (e.g., cobalt or nickel) may be at least partially removed from PCD table 68. A catalyst material may be removed from at least a portion of PCD table 68 using any suitable technique, such as, for example, acid leaching. In some examples, PCD table 68 may be exposed to a leaching solution until a catalyst material is substantially removed from PCD table 68 to a desired depth relative to one or more surfaces of PCD table 68.
According to some embodiments, the PCD table 68 may be fabricated by subjecting a plurality of diamond particles to an HPHT sintering process in the presence of a metal-solvent catalyst (e.g., cobalt, nickel, iron, or alloys thereof) to facilitate intergrowth between the diamond particles and form a PCD body comprised of bonded diamond grains that exhibit diamond-to-diamond bonding therebetween. For example, the metal-solvent catalyst may be mixed with the diamond particles, infiltrated from a metal-solvent catalyst foil or powder adjacent to the diamond particles, infiltrated from a metal-solvent catalyst present in a cemented carbide substrate, or combinations of the foregoing. The bonded diamond grains (e.g., sp3-bonded diamond grains), so-formed by HPHT sintering the diamond particles, define interstitial regions with the metal-solvent catalyst disposed within the interstitial regions. The diamond particles may exhibit a selected diamond particle size distribution.
The as-sintered PCD body may be leached by immersion in an acid, such as aqua regia, nitric acid, hydrofluoric acid, or subjected to another suitable process to remove at least a portion of the metal-solvent catalyst from the interstitial regions of the PCD body and form the PCD table 68. For example, the as-sintered PCD body may be immersed in the acid for about 2 to about 7 days (e.g., about 3, 5, or 7 days) or for a few weeks (e.g., about 4 weeks) depending on the process employed. Even after leaching, a residual, detectable amount of the metal-solvent catalyst may be present in the at least partially leached PCD table 68. It is noted that when the metal-solvent catalyst is infiltrated into the diamond particles from a cemented tungsten carbide substrate including tungsten carbide particles cemented with a metal-solvent catalyst (e.g., cobalt, nickel, iron, or alloys thereof), the infiltrated metal-solvent catalyst may carry tungsten and/or tungsten carbide therewith and the as-sintered PCD body may include such tungsten and/or tungsten carbide therein disposed interstitially between the bonded diamond grains. The tungsten and/or tungsten carbide may be at least partially removed by the selected leaching process or may be relatively unaffected by the selected leaching process.
The plurality of diamond particles used to form the PCD table 68 may exhibit one or more selected sizes. The one or more selected sizes may be determined, for example, by passing the diamond particles through one or more sizing sieves or by any other method. In an embodiment, the plurality of diamond particles may include a relatively larger size and at least one relatively smaller size. As used herein, the phrases “relatively larger” and “relatively smaller” refer to particle sizes determined by any suitable method, which differ by at least a factor of two (e.g., 40 μm and 20 μm). More particularly, in various embodiments, the plurality of diamond particles may include a portion exhibiting a relatively larger size (e.g., 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 15 μm, 12 μm, 10 μm, 8 μm) and another portion exhibiting at least one relatively smaller size (e.g., 30 μm, 20 μm, 15 μm, 12 μm, 10 μm, 8 μm, 4 μm, 2 μm, 1 μm, 0.5 μm, less than 0.5 μm, 0.1 μm, less than 0.1 μm). In another embodiment, the plurality of diamond particles may include a portion exhibiting a relatively larger size between about 40 μm and about 15 μm and another portion exhibiting a relatively smaller size between about 12 μm and 2 μm. Of course, the plurality of diamond particles may also include three or more different sizes (e.g., one relatively larger size and two or more relatively smaller sizes) without limitation.
In at least one embodiment, substrate 67 may be at least partially covered with a protective layer, such as, for example, a polymer cup, to prevent corrosion of substrate 67 during leaching. In additional embodiments, table 68 may be separated from substrate 67 prior to leaching table 68. For example, table 68 may be removed from substrate 67 and placed in a leaching solution so that all or selected surfaces of table 68 are at least partially leached. In various examples, table 68 may be reattached to substrate 67 or attached to a new substrate 67 following leaching. Table 68 may be attached to substrate 67 using any suitable technique, such as, for example, mechanical attachment, brazing, welding, or HPHT processing.
As shown in
In at least one embodiment, cutting face 70 may have a partially arcuate periphery. In another embodiment, cutting face 70 may have a substantially semi-circular periphery. For example, two cutting elements 22 may be cut from a single substantially circular cutting element blank, resulting in two substantially semi-circular cutting elements 22. In some embodiments, angular portions of peripheral surface 75 may be rounded to form a substantially arcuate surface around cutting element 22.
As illustrated in
In at least one embodiment, cutting face 170 may have a substantially arcuate periphery. In another embodiment, cutting face 170 may have a substantially circular periphery. Cutting element 26 may also comprise a cutting edge having a chamfer 172 formed along at least a portion of a periphery of table 168 between cutting face 170 and peripheral surface 175. According to some embodiments, chamfer 172 may be formed along substantially the entire periphery of table 168. Table 168 may also include any other suitable surface shape between cutting face 170 and peripheral surface 175, including, without limitation, an arcuate surface, a sharp edge, and/or a honed edge. Such a cutting edge may be configured to contact and/or cut a subterranean formation as drilling assembly 10 is rotated relative to a subterranean formation (as will be described in greater detail in connection with
The position and orientation of cutting elements 22 of drill bit 12 and cutting elements 26 of reamer member 16 may facilitate drilling of borehole 63 in formation 76 as drilling assembly 10 is rotated within borehole 63. As drilling assembly 10 is forced against formation 76 and rotated relative to formation 76, debris, such as cuttings, may be removed from formation 76, thereby lengthening and/or widening borehole 63. Cuttings may comprise pulverized material, fractured material, sheared material, a continuous chip, and/or any other form of cutting, without limitation. Accordingly to at least one embodiment, drill bit 12 may function as a non-coring drill bit, with cutting elements 22 being sized and positioned on drill bit 12 so as to prevent a core of subterranean formation material from being formed at a forward end 73 of borehole 63. For example, cutting elements 22 may be positioned on drill bit 12 so as to form a generally apical cutting tip that cuts borehole 63 without forming a central core within a distal end of borehole 63 during drilling.
As illustrated in
Drilling assembly 10 may be configured to form forward borehole portion 64 of borehole 63 to be sized such that a threaded portion of a subterranean support-bolt may be securely attached or bonded into (e.g., by epoxy, brazing, press-fit, or as otherwise known in the art) and held within borehole portion 64. Accordingly, drill bit 12 and spacer 14 of drilling assembly 10 may have a combined length configured to form forward borehole portion 64 to have a length that securely accommodates a threaded portion of a support bolt. Reamer member 16 may be configured to widen expanded borehole portion 65 of borehole 63 so as to accommodate a portion of a subterranean support-bolt that is between a threaded portion and a head of the subterranean support-bolt. Expanded borehole portion 65 of borehole 63 may have a diameter that enables a threaded portion of a subterranean support bolt to be inserted into borehole 63 without the necessity of driving the threaded portion the entire length of borehole 63.
For example, an operator may insert the threaded portion of a subterranean support bolt, such as a lag bolt or other threaded support bolt, axially through the length of expanded borehole portion 65 of borehole 63, without the necessity of screwing the threaded portion of support bolt the into the formation material defining expanded borehole portion 65. The subterranean support bolt may subsequently be driven into the formation material defining forward borehole portion 64 of borehole 63, which has a smaller diameter than expanded borehole portion 65. Accordingly, a significant amount of energy and time may be conserved, since it is not necessary to screw the threaded portion of a support bolt through rock material over the entire length of borehole 63. Moreover, expanded borehole portion 65 of borehole 63 may be widened so as to accommodate a portion of a support bolt, such as a lag bolt, that is wider than a threaded portion of the support bolt. Additionally, drilling assembly 10 may enable a borehole having at least two separate diameters, such as borehole 63, to be formed without the necessity of using at least two separate drill bits having different diameters. Accordingly, a borehole having at least two separate diameters may be formed during a single drilling operation using drilling assembly 10, as opposed to being formed over the course of two or more drilling operations using two or more separate drill bits having different diameters.
As illustrated in
Bit body 220 may also comprise at least one cutter pocket 239 for securing a cutting element 226 to bit body 220. Cutter pockets 239 may each include at least one mounting surface, such as back mounting surface 240. Cutting elements 226 may be mounted to bit body 220 so that portions of cutting elements 226 abut cutter pockets 239. Cutting elements 226 may each comprise a layer or table 268 affixed to or formed upon a substrate 267. Table 268 may be formed of any material or combination of materials suitable for cutting subterranean formations, including, for example, a superhard or superabrasive material such as polycrystalline diamond (PCD). Similarly, substrate 267 may comprise any material or combination of materials capable of adequately supporting a superabrasive material during drilling of a subterranean formation, including, for example, cemented tungsten carbide. For example, cutting element 226 may comprise a table 268 comprising polycrystalline diamond bonded to a substrate 267 comprising cobalt-cemented tungsten carbide. In at least one embodiment, after forming table 268, a catalyst material (e.g., cobalt or nickel) may be at least partially removed from table 268 using any suitable technique, such as, for example, acid leaching.
Cutting elements 226 may each comprise a cutting face 270 formed by table 268, a peripheral surface 275 formed by table 268 and substrate 267, and a back surface 274 formed by substrate 267. According to various embodiments, cutting face 270 may be substantially planar and peripheral surface 275 may be substantially perpendicular to cutting face 270. Back surface 274 may be spaced away from and, in some embodiments, substantially parallel to cutting face 270. Back surfaces 274 of cutting elements 226 may be mounted and secured to back mounting surfaces 240 of cutter pockets 239, as shown in
As illustrated in
Bit body 220 may also comprise at least one inward sloping surface 287. Inward sloping surfaces 287 may guide debris away from a forward portion of drill bit 200. Additionally, inward sloping surfaces 287 may enable a clearance to be provided between bit body 220 and a subterranean formation during drilling. Inward sloping surfaces 287 may be defined radially inward from peripheral side surface 241. According to some embodiments, bit body 220 may also comprise at least one opening, such as a fluid port or vacuum opening, for conveying fluid and/or or material toward or away from a forward portion of drill bit 200. For example, in a wet drilling environment, drilling fluid may be directed through an opening in bit body 220 toward a forward portion of drill bit 200. In additional embodiments, debris, such as rock cuttings, may be conveyed away from drill bit 200 through an internal passage, such as a vacuum hole. Drilling fluids and cutting debris may also be conveyed away from drill bit 200 via channels formed in an exterior of bit body 220 and/or an exterior of a drill steel coupled to drill bit 200.
According to various embodiments, drill bit 200 may comprise a central pilot 282 extending from bit body 220 in an axially forward direction. For example, as illustrated in
It is currently believed that having a central pilot with a length of greater than 1, greater than 2, or greater than 3 inches can protect the axially trailing cutting elements. In one embodiment, the central pilot comprises cobalt-cemented tungsten carbide or any other non-diamond material (e.g., a metal) and the axially trailing cutting elements comprise polycrystalline diamond or any other polycrystalline superhard material.
Central pilot 282 may comprise any suitable material or combination of materials, including, for example, hard and/or superhard materials, such as cemented tungsten carbide, polycrystalline diamond, and/or steel, without limitation. According to at least one embodiment, central pilot 282 may be integrally formed with bit body 220. In some embodiments, central pilot 282 may comprise a separate member that is coupled to bit body 220, as will be discussed in greater detail below with reference to
As shown in
Central pilot 282 may comprise any suitable shape and/or configuration, without limitation. According to some embodiments, central pilot 282 may have at least one cutting edge configured to cut away material from a formation, such as rock material, carbonaceous material, and/or other subterranean material, during drilling. For example, as illustrated in
Central pilot 282 may also comprise at least one projection face 286 located radially inward of peripheral side surface 285. According to at least one embodiment, a forward projection cutting edge 283 may be located at a forward portion of each projection face 286. A projection face edge 277 may also be located on a periphery of projection face 286. For example, projection face edge 277 may be located at an intersection of projection face 286 and peripheral side surface 285. According to some embodiments, projection face edge 277 may act as a cutting edge during drilling. Forward projection cutting edges 283 and/or projection face peripheral edges 277 may comprise any suitable edge shape, including, without limitation, a sharp edge, a chamfered edge, an arcuate surface (e.g., a radius), multiple chamfers/radii, a honed edge, and/or combinations of the foregoing. Forward projection cutting edges 283 and/or projection face peripheral edges 277 may be configured to contact and/or cut a subterranean formation as drill bit 200 is rotated relative to a subterranean formation.
As shown in
Projection tip 284 of central pilot 282 may have a substantially apical shape centered about central axis 218 and a smaller diameter than a portion of drill bit 200 that includes bit body 220 and cutting elements 226. Accordingly, central pilot 282 may facilitate an efficient and controlled entry of drill bit 200 into formation 276, while preventing skipping or walking of drill bit 200 over surface 288 of formation 276 at the beginning of drilling a new borehole. With central pilot 282 being disposed within pilot hole 289, the orientation of drill bit 200 may be stabilized with respect to entry into a surface of formation 276. Accordingly, drill bit 200 may progress in forward direction 278 as central pilot 282 cuts into formation 276.
Cutting elements 226 of drill bit 200 may subsequently contact formation 276 following the initial formation of pilot hole 289 by central pilot 282. For example, as shown in
According to at least one embodiment, drill bit 200 may be utilized to drill boreholes 290 at angles of θ1 ranging from approximately 30° to approximately 150° relative to surface 288 of formation 276.
According to at least one embodiment, bit body 320 may comprise a peripheral side surface 341 and a through-hole 392 for coupling central pilot 382 and rearward coupling portion 369 to bit body 320. Central pilot 382 may be integrally formed with and/or coupled to rearward coupling portion 369 by a connection member 393 that is disposed and/or secured within through-hole 392. Connection member 393 may comprise any suitable shape and/or configuration, without limitation, and through-hole 392 may comprise any suitable shape for securely holding connection member 393. Connection member 393 may be configured to be temporarily or permanently coupled to bit body 320 (e.g., by threaded connection, pin connection, mechanical attachment, brazing, welding, bonding, interference fit, and/or other suitable coupling).
As illustrated in
Bit body 420 may also comprise at least one cutter pocket 439 for securing a cutting element 426 to bit body 420. Cutter pockets 439 may each include at least one mounting surface, such as back mounting surface 440, for securing cutting element 426 to bit body 420. Cutting elements 426 may be mounted to bit body 420 so that portions of cutting elements 426 abut cutter pockets 439. Cutting elements 426 may each comprise a layer or table 468 affixed to or formed upon a substrate 467. Table 468 may be formed of any material or combination of materials suitable for cutting subterranean formations, including, for example, a superhard or superabrasive material such as polycrystalline diamond (PCD). Similarly, substrate 467 may comprise any material or combination of materials capable of adequately supporting a superabrasive material during drilling of a subterranean formation, including, for example, cemented tungsten carbide. For example, cutting element 426 may comprise a table 468 comprising polycrystalline diamond bonded to a substrate 467 comprising cobalt-cemented tungsten carbide. In at least one embodiment, after forming table 468, a catalyst material (e.g., cobalt or nickel) may be at least partially removed from table 468 using any suitable technique, such as, for example, acid leaching.
Cutting elements 426 may each comprise a cutting face 470 formed by table 468, a peripheral surface 475 formed by table 468 and substrate 467, and a back surface 474 formed by substrate 467. According to various embodiments, cutting face 470 may be substantially planar and peripheral surface 475 may be substantially perpendicular to cutting face 470. Back surface 474 may be spaced away from and, in some embodiments, substantially parallel to cutting face 470. Back surfaces 474 of cutting elements 426 may be mounted and secured to back mounting surfaces 440 of cutter pockets 439, as shown in
As illustrated in
According to various embodiments, drill bit 400 may comprise a central pilot 482 extending from bit body 420 in an axially forward direction. For example, as illustrated in
It is currently believed that having a central pilot with a length of greater than 1, greater than 2, or greater than 3 inches can protect the axially trailing cutting elements. In one embodiment, the central pilot comprises cobalt-cemented tungsten carbide or any other non-diamond material (e.g., a metal) and the axially trailing cutting elements comprise polycrystalline diamond or any other polycrystalline superhard material.
Central pilot 482 may comprise any suitable material or combination of materials, including, for example, hard and/or superhard materials, such as cemented tungsten carbide, polycrystalline diamond, and/or steel, without limitation. According to at least one embodiment, central pilot 482 may be integrally formed with bit body 420. In other embodiments, central pilot 482 may comprise a separate member that is coupled to bit body 420.
As shown in
Central pilot 482 may comprise any suitable shape and/or configuration, without limitation. According to some embodiments, central pilot 482 may have at least one cutting edge configured to cut away material, such as rock, carbonaceous material, and/or other subterranean material, during drilling. For example, as illustrated in
Central pilot 482 may also comprise at least one projection face 486 and/or a sloped projection surface 471 located radially inward of peripheral side surface 485. Projection face 486 and sloped projection surface 471 may comprise any suitable shape, without limitation. For example, as illustrated in
According to various embodiments, during drilling, central pilot 482 may contact a subterranean formation prior to bit body 420 and cutting elements 426, even when drill bit 400 is oriented at a non-perpendicular angle relative to a surface of the formation (see, e.g.,
Cutting elements 426 of drill bit 400 may subsequently contact the formation following the initial formation of a pilot hole by central pilot 482. For example, cutting edges of cutting elements 426 may form a borehole within the formation. Such a borehole formed by cutting elements 426 may follow in the same forward direction as a pilot hole formed by central pilot 482. Projection tip 484 of central pilot 482, which may have a smaller diameter than a portion of drill bit 400 that includes bit body 420 and cutting elements 426, may more efficiently begin cutting into a subterranean formation at a desired location and angle relative to a surface of the formation. Additionally, central pilot 482 may facilitate cutting of a borehole as central pilot 482 guides drill bit 400 into formation 476 at the desired angle and orientation. Skipping of drill bit 400 over a surface of a formation may also be prevented by central pilot 482. Drill bit 400 may be configured to drill boreholes at a variety of angles relative to a surface of subterranean formation 476. According to at least one embodiment, drill bit 400 may be utilized to drill boreholes 490 at angles ranging from approximately 30° to approximately 150° (as shown in
As illustrated in
Bit body 520 may also comprise at least one cutter pocket 539 for securing a cutting element 526 to bit body 520. Cutter pockets 539 may each include at least one mounting surface, such as back mounting surface 540. Cutting elements 526 may be mounted to bit body 520 so that portions of cutting elements 526 abut cutter pockets 539. Cutting elements 526 may each comprise a layer or table 568 affixed to or formed upon a substrate 567. Table 568 may be formed of any material or combination of materials suitable for cutting subterranean formations, including, for example, a superhard or superabrasive material such as polycrystalline diamond (PCD). Similarly, substrate 567 may comprise any material or combination of materials capable of adequately supporting a superabrasive material during drilling of a subterranean formation, including, for example, cemented tungsten carbide. For example, cutting element 526 may comprise a table 568 comprising polycrystalline diamond bonded to a substrate 567 comprising cobalt-cemented tungsten carbide. In at least one embodiment, after forming table 568, a catalyst material (e.g., cobalt or nickel) may be at least partially removed from table 568 using any suitable technique, such as, for example, acid leaching.
Cutting elements 526 may each comprise a cutting face 570 formed by table 568, a peripheral surface 575 formed by table 568 and substrate 567, and a back surface 574 formed by substrate 567. According to various embodiments, cutting face 570 may be substantially planar and peripheral surface 575 may be substantially perpendicular to cutting face 570. Back surface 574 may be spaced away from and, in some embodiments, substantially parallel to cutting face 570. Back surfaces 574 of cutting elements 526 may be mounted and secured to back mounting surfaces 540 of cutter pockets 539, as shown in
As illustrated in
According to various embodiments, drill bit 500 may comprise a central pilot 582 extending from bit body 520 in an axially forward direction. For example, as illustrated in
It is currently believed that having a central pilot with a length of greater than 1, greater than 2, or greater than 3 inches can protect the axially trailing cutting elements. In one embodiment, the central pilot comprises cobalt-cemented tungsten carbide or any other non-diamond material (e.g., a metal) and the axially trailing cutting elements comprise polycrystalline diamond or any other polycrystalline superhard material.
Central pilot 582 may comprise any suitable material or combination of materials, including, for example, hard and/or superhard materials, such as cemented tungsten carbide, polycrystalline diamond, and/or steel, without limitation. According to at least one embodiment, central pilot 582 may be integrally formed with bit body 520. In other embodiments, central pilot 582 may comprise a separate member that is coupled to bit body 520.
As shown in
Central pilot 582 may comprise any suitable shape and/or configuration, without limitation. According to some embodiments, central pilot 582 may comprise a projection cutting element 501 mounted in a mounting recess 502. In at least one embodiment, central pilot 582 may comprise a projection cutting element 501 that is substantially centered about central axis 518. Projection cutting element 501 may be formed of any material or combination of materials suitable for cutting a subterranean formation material, including, for example, cobalt-cemented tungsten carbide, polycrystalline diamond (PCD), and/or any other suitable material. According to at least one embodiment, cutting element 501 may comprise a PCD table formed on a substrate. For example, a PCD table of cutting element 501 may be positioned and formed so as to define one or more portions of cutting element 501, such as cutting faces 503, cutting tip 504, forward cutting edges 505, and/or cutting edges 506, without limitation.
Projection cutting element 501 may comprise at least one cutting face 503. For example, projection cutting element 501 may include two cutting faces 503 on opposite sides of projection cutting element 501. Each cutting face 503 may face generally in a rotational direction 579 of drill bit 500. Projection cutting element 501 may additionally comprise a cutting tip 504 located at projection forward end 531. Cutting tip 504 of cutting element 501 may comprise a forward projection surface and/or edge centered about central axis 518. Projection cutting element 501 may also have at least one cutting edge configured to cut away material, such as rock material, carbonaceous material, and/or other subterranean material, during drilling. For example, as illustrated in
According to various embodiments, during drilling, central pilot 582 may contact a subterranean formation prior to bit body 520 and cutting elements 526, even when drill bit 500 is oriented at a non-perpendicular angle relative to a surface of the formation (see, e.g.,
Cutting elements 526 of drill bit 500 may subsequently contact the formation following the initial formation of a pilot hole by central pilot 582. For example, cutting edges of cutting elements 526 may form a borehole within the formation. Such a borehole formed by cutting elements 526 may follow in the same forward direction as a pilot hole formed by central pilot 582. Projection tip 584 of central pilot 582, which may have a smaller diameter than a portion of drill bit 500 that includes bit body 520 and cutting elements 526, may more efficiently begin cutting into a subterranean formation at a desired location and angle relative to a surface of the formation. Additionally, central pilot 582 may facilitate cutting of a borehole as central pilot 582 guides drill bit 500 into formation 576 at the desired angle and orientation. Drill bit 500 may be configured to drill boreholes at a variety of angles relative to a surface of subterranean formation 576. According to at least one embodiment, drill bit 500 may be utilized to drill boreholes 590 at angles ranging from approximately 30° to approximately 150° (as shown in
As illustrated in
Bit body 620 may also comprise at least one cutter pocket 639 for securing a cutting element 626 to bit body 620. Cutter pockets 639 may each include at least one mounting surface, such as back mounting surface 640. Cutting elements 626 may be mounted to bit body 620 so that portions of cutting elements 626 abut cutter pockets 639. Cutting elements 626 may each comprise a layer or table 668 affixed to or formed upon a substrate 667. Table 668 may be formed of any material or combination of materials suitable for cutting subterranean formations, including, for example, a superhard or superabrasive material such as polycrystalline diamond (PCD). Similarly, substrate 667 may comprise any material or combination of materials capable of adequately supporting a superabrasive material during drilling of a subterranean formation, including, for example, cemented tungsten carbide. For example, cutting element 626 may comprise a table 668 comprising polycrystalline diamond bonded to a substrate 667 comprising cobalt-cemented tungsten carbide. In at least one embodiment, after forming table 668, a catalyst material (e.g., cobalt or nickel) may be at least partially removed from table 668 using any suitable technique, such as, for example, acid leaching.
Cutting elements 626 may each comprise a cutting face 670 formed by table 668, a peripheral surface 675 formed by table 668 and substrate 667, and a back surface 674 formed by substrate 667. According to various embodiments, cutting face 670 may be substantially planar and peripheral surface 675 may be substantially perpendicular to cutting face 670. Back surface 674 may be spaced away from and, in some embodiments, substantially parallel to cutting face 670. Back surfaces 674 of cutting elements 626 may be mounted and secured to back mounting surfaces 640 of cutter pockets 639, as shown in
As illustrated in
According to various embodiments, drill bit 600 may comprise a central pilot 682 extending from bit body 620 in an axially forward direction. For example, as illustrated in
Central pilot 682 may comprise any suitable material or combination of materials, including, for example, hard and/or superhard materials, such as cemented tungsten carbide, polycrystalline diamond, and/or steel, without limitation. According to at least one embodiment, central pilot 682 may be integrally formed with bit body 620. In other embodiments, central pilot 682 may comprise a separate member that is coupled to bit body 620.
As shown in
Central pilot 682 may comprise any suitable shape and/or configuration, without limitation. According to some embodiments, central pilot 682 may comprise at least one projection cutting element 722 mounted in corresponding cutter pockets 739. Cutter pockets 739 may each include at least one mounting surface, such as back mounting surface 740, for securing projection cutting element 722 to bit body 720. Projection cutting elements 722 may be mounted to central pilot 682 so that portions of projection cutting elements 722 abut cutter pockets 739. According to some embodiments, projection cutting elements 722 may each comprise a layer or table 768 affixed to or formed upon a substrate 767. Table 768 may be formed of any material or combination of materials suitable for cutting subterranean formations, including, for example, a superhard or superabrasive material such as polycrystalline diamond (PCD). Similarly, substrate 767 may comprise any material or combination of materials capable of adequately supporting a superabrasive material during drilling of a subterranean formation, including, for example, cemented tungsten carbide. For example, projection cutting element 722 may comprise a table 768 comprising polycrystalline diamond bonded to a substrate 767 comprising cobalt-cemented tungsten carbide. In at least one embodiment, after forming table 768, a catalyst material (e.g., cobalt or nickel) may be at least partially removed from table 768 using any suitable technique, such as, for example, acid leaching.
Projection cutting elements 722 may each comprise a cutting face 770 formed by table 768, a side surface 775 formed by table 768 and substrate 767, and a back surface 774 formed by substrate 767. According to various embodiments, cutting face 770 may be substantially planar and side surface 775 may be substantially perpendicular to cutting face 770. Back surface 774 may be spaced away from and, in some embodiments, substantially parallel to cutting face 770. Back surfaces 774 of cutting elements 722 may be mounted and secured to back mounting surfaces 740 of cutter pockets 739, as shown in
As illustrated in
According to various embodiments, during drilling, central pilot 682 may contact a subterranean formation prior to bit body 620 and cutting elements 626, even when drill bit 600 is oriented at a non-perpendicular angle relative to a surface of the formation (see, e.g.,
Cutting elements 626 of drill bit 600 may subsequently contact the formation following the initial formation of a pilot hole by central pilot 682. For example, cutting edges of cutting elements 626 may form a borehole within the formation. Such a borehole formed by cutting elements 626 may follow in the same forward direction as a pilot hole formed by central pilot 682. Projection forward end 631 of central pilot 682, which may have a smaller diameter than a portion of drill bit 600 that includes bit body 620 and cutting elements 626, may more efficiently begin cutting into a subterranean formation at a desired location and angle relative to a surface of the formation. Additionally, central pilot 682 may facilitate cutting of a borehole as central pilot 682 guides drill bit 600 into formation 676 at the desired angle and orientation. Drill bit 600 may be configured to drill boreholes at a variety of angles relative to a surface of subterranean formation 676. According to at least one embodiment, drill bit 600 may be utilized to drill boreholes 690 at angles ranging from approximately 30° to approximately 150° (as shown in
The preceding description has been provided to enable others skilled the art to best utilize various aspects of the exemplary embodiments described herein. This exemplary description is not intended to be exhaustive or to be limited to any precise form disclosed. Many modifications and variations are possible without departing from the spirit and scope of the instant disclosure. It is desired that the embodiments described herein be considered in all respects illustrative and not restrictive and that reference be made to the appended claims and their equivalents for determining the scope of the instant disclosure.
Unless otherwise noted, the terms “a” or “an,” as used in the specification and claims, are to be construed as meaning “at least one of.” In addition, for ease of use, the words “including” and “having,” as used in the specification and claims, are interchangeable with and have the same meaning as the word “comprising.”
This application is a continuation of U.S. patent application Ser. No. 14/887,311 titled “Rotational Drill Bits and Drilling Apparatuses Including the Same” and filed 19 Oct. 2015, which is a continuation of U.S. patent application Ser. No. 13/840,702 titled “Rotational Drill Bits and Drilling Apparatuses Including the Same” and filed 15 Mar. 2013, each of which is hereby incorporated by reference in its entirety.
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| Number | Date | Country | |
|---|---|---|---|
| 20180230752 A1 | Aug 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14887311 | Oct 2015 | US |
| Child | 15950998 | US | |
| Parent | 13840702 | Mar 2013 | US |
| Child | 14887311 | US |
