WO2023023267A1

WO2023023267A1 - Drill rods having stabilizers, and systems and methods comprising same

Info

Publication number: WO2023023267A1
Application number: PCT/US2022/040787
Authority: WO
Inventors: Christopher L. Drenth; Adrian BRUBACHER
Original assignee: Longyear Tm, Inc.
Priority date: 2021-08-20
Filing date: 2022-08-18
Publication date: 2023-02-23
Also published as: AU2021106799A4; PE20240746A1; CL2024000518A1; EP4388170A1

Abstract

A drill rod having a central axis can comprise a hollow, elongate body having a box end portion and an opposing pin end portion. The elongate body can have an outer surface that defines a circumference of the elongate body. A plurality of stabilizing projections can extend outwardly from the circumference of the elongate body. The plurality of stabilizing projections can be positioned proximate to the box end portion. The plurality of stabilizing projections can be spaced about the circumference of the elongate body.

Description

DRILL RODS HAVING STABILIZERS, AND SYSTEMS AND METHODS COMPRISING SAME

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of the filing date of U.S. Provisional Patent Application No. 63/235,440, filed August 20, 2021, the entirety of which is hereby incorporated by reference herein.

FIELD

[0002] The present disclosure relates to drill rods and, in particular, to drill rods having stabilizers.

BACKGROUND

[0003] Drill rods commonly connect to each other with an interference fit between the box end of a first rod and the pin end of a second rod. Such an interference fit causes the box end to have the widest diameter of the drill rod along the length of the drill rod. Accordingly, drill rods can be particularly prone to failure (e.g., buckling, twisting, cracking) due to rubbing and/or overloading at the pin end.

SUMMARY

[0004] Described herein, in various aspects, is a drill rod having a central axis comprising an elongate body having a box end portion and an opposing pin end portion. The elongate body can have an outer surface that defines a circumference of the elongate body, wherein the elongate body is hollow. A plurality of stabilizing projections (e.g., optionally, wear strips) can extend outwardly from the circumference of the elongate body. The plurality of stabilizing projections can be positioned proximate to the box end portion. The plurality of stabilizing projections can be spaced about the circumference of the elongate body.

[0005] A drill string can comprise a plurality of drill rods. Each drill rod can have a central axis and can comprise an elongate body having a box end portion and an opposing pin end portion, wherein the elongate body is hollow. The elongate body can have an outer surface that defines a circumference of the elongate body. A plurality of stabilizing projections (e.g., optionally, wear strips) can extend outwardly from the circumference of the elongate body. The plurality of stabilizing projections can be positioned proximate to the box end portion. The plurality of stabilizing projections can be spaced about the circumference of the elongate body. The plurality of drill rods can be coupled together end-to-end to form the drill string.

[0006] A method can comprise advancing a drill string within a formation, the drill string comprising a plurality of drill rods coupled end-to-end. Each drill rod can have a central axis and can comprise an elongate body having a box end portion and an opposing pin end portion, wherein the elongate body is hollow. The elongate body can have an outer surface that defines a circumference of the elongate body. A plurality of stabilizing projections (e.g., optionally, wear strips) can extend outwardly from the circumference of the elongate body. The plurality of stabilizing projections can be positioned proximate to the box end portion. The plurality of stabilizing projections can be spaced about the circumference of the elongate body.

[0007] A method can comprise cladding, by a laser, a plurality of wear strips to an outer surface of a box end portion of a drill rod, the drill rod having a circumference. The plurality of wear strips can be spaced about the circumference of the drill rod.

[0008] Additional advantages of the invention will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

DESCRIPTION OF THE DRAWINGS

[0009] These and other features of the preferred embodiments of the invention will become more apparent in the detailed description in which reference is made to the appended drawings wherein:

[0010] FIG. 1 is a perspective view of a plurality of drill rods as disclosed herein.

[0011] FIG. 2 is partial perspective view of box ends of a plurality of drill rods disclosed herein. [0012] FIG. 3 is a schematic diagram of a box end portion of a drill rod in accordance with embodiments disclosed herein.

[0013] FIG. 4 is a schematic diagram of a drill rod as disclosed herein.

[0014] FIG. 5 is a schematic diagram of a drills string, comprising a plurality of drill rods as disclosed herein, within a borehole.

[0015] FIG. 6 is a partial perspective view of an exemplary drill rod as disclosed herein, the drill rod comprising plurality of stabilizing projections that are formed into the drill rod.

[0016] FIG. 7 is another partial perspective view of the drill rod of FIG. 6.

DETAILED DESCRIPTION

[0017] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. It is to be understood that this invention is not limited to the particular methodology and protocols described, as such may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention.

[0018] Many modifications and other embodiments of the invention set forth herein will come to mind to one skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing description and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0019] As used herein the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. For example, use of the term “a wear strip” can refer to one or more of such wear strips, and so forth. [0020] All technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs unless clearly indicated otherwise.

[0021] Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. Optionally, in some aspects, when values are approximated by use of the antecedent “about,” it is contemplated that values within up to 15%, up to 10%, up to 5%, or up to 1% (above or below) of the particularly stated value can be included within the scope of those aspects. Similarly, in some optional aspects, when values are approximated by use of the terms “substantially” or “generally,” it is contemplated that values within up to 15%, up to 10%, up to 5%, or up to 1% (above or below) of the particular value can be included within the scope of those aspects. When used with respect to an identified property or circumstance, “substantially” or “generally” can refer to a degree of deviation that is sufficiently small so as to not measurably detract from the identified property or circumstance, and the exact degree of deviation allowable may in some cases depend on the specific context.

[0022] As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0023] As used herein, the term “at least one of’ is intended to be synonymous with “one or more of.” For example, “at least one of A, B and C” explicitly includes only A, only B, only C, and combinations of each.

[0024] The word “or” as used herein means any one member of a particular list and also includes any combination of members of that list.

[0025] It is to be understood that unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; and the number or type of aspects described in the specification.

[0026] The following description supplies specific details in order to provide a thorough understanding. Nevertheless, the skilled artisan would understand that the apparatus, system, and associated methods of using the apparatus can be implemented and used without employing these specific details. Indeed, the apparatus, system, and associated methods can be placed into practice by modifying the illustrated apparatus, system, and associated methods and can be used in conjunction with any other apparatus and techniques conventionally used in the industry.

[0027] Referring to FIGS. 1-4, a drill rod 10 having a central axis 12 can comprise an elongate body 14 having a box end portion 16 and an opposing pin end portion 18. The elongate body 14 can be hollow, with a central bore extending through and between the box and pin end portions. The box end portion 16 can be configured to receive and couple to a pin end portion of an adjacent drill rod (e.g., via threaded coupling). For example, the box end portion 16 (e.g., an interior surface of the box end portion) can define at least one female thread that is configured to receive one or more corresponding, complementary male threads of the pin end portion (e.g., defined on an exterior surface of the pin end portion) of the adjacent drill rod. Optionally, the box and pin end portions 16, 18 can be configured for interference fits with adjacent drill rods.

[0028] The elongate body 14 can have an outer surface 20 that defines a circumference of the elongate body. A plurality of stabilizing projections 21 can extend outwardly from the circumference of the elongate body. The plurality of stabilizing projections 21 can be positioned at or proximate to the box end portion 16 of the elongate body 14. In some optional aspects, the plurality of stabilizing projections 21 can comprise a plurality of wear strips 22, which can be bonded to the outer surface 20 of the elongate body 14 proximate to the box end portion 16. Thus, in exemplary aspects, the wear strips 22 are not brazed to the outer surface 20 of the elongate body 14. In further or alternative aspects, the elongate body 14 can be formed to define the plurality of stabilizing projections 21. For example, in these aspects, the stabilizing projections 16 can be formed as integral portions of the elongate body 14 (such that the elongate body and the stabilizing projections are formed as one monolithic structure). The plurality of stabilizing projections 21 can be spaced about the circumference of the elongate body 14. In some optional aspects, the plurality of stabilizing projections 21 can be equally spaced about the circumference of the elongate body 14. In further optional aspects, the plurality of stabilizing projections 21 can be unequally spaced about the circumference of the elongate body 14 such that a circumferential spacing between a first pair of stabilizing projections is different than a circumferential spacing between a second pair of sequential stabilizing projections.

[0029] In some aspects, stabilizing projections 21 can be arranged in a helical orientation. For example, in some aspects, when the stabilizing projections comprise wear strips 22, the wear strips can be bonded to the outer surface 20 of the elongate body 14 in a helical orientation. In exemplary aspects, the stabilizing projections 21 can each extend along a centerline 29. The centerline can be spaced equally between opposed sides of the stabilizing projections that are spaced along an axis transverse to the longitudinal axis of the drill rod. In exemplary aspects, the centerline 29 can have a helical profile corresponding to the helical profile of the stabilizing projections. In some aspects, the centerline each stabilizing projection 21 (e.g., optionally, wear strip 22) of the plurality of stabilizing projections can intersect a cross-sectional plane 30 that contains the central axis 12 of the drill rod 10 at an acute angle 0. That is, in some optional aspects, and with reference to FIG. 3, a line tangent to the centerline 29 of each stabilizing projection 21 can form an acute angle 0 with the cross- sectional plane 30 that contains the central axis 12 of the drill rod 10. In various optional aspects, the acute angle 0 can be from about 5 to about 45 degrees, or from about 10 to about 30 degrees, or about 20 degrees. Optionally, the stabilizing projections 21 can wrap around the outer surface 20 of the elongate body 14 in a clockwise direction along an axial direction from the pin end portion to the box end portion. In this way, the stabilizing projections 21 can promote flow of cuttings and fluid as the drill rod rotates. In further aspects, the stabilizing projections 21 can wrap around the outer surface 20 of the elongate body 14 in a counter-clockwise direction along an axial direction from the pin end portion to the box end portion.

[0030] In some aspects, and with reference to FIGS. 6-7, the stabilizing projections 21 can be formed from the elongate body 14. For example, the stabilizing projections 21 can be formed at least partly by deforming the elongate body 12. This can be done, for example, by inserting a tool into the elongate body 14 and applying a outward force/pressure (e.g., via a hydraulic system) to an internal surface of the elongate body to cause portions to expand radially outwardly, thereby plastically deforming the elongate body to form the stabilizing projections 21. In other exemplary aspects, the stabilizing projections 21 can be formed at least partly by hydroforming. For example, an external die can be positioned around the elongate body 14, and a hydraulic pressure can cause the elongate body 14 to plastically deform into the die.

[0031] In exemplary aspects, the stabilizing projections 21 formed into the elongate body can have increased wear resistance by induction case-hardening and/or by adding surface coating. For example, in some optional aspects, the stabilizing projections 21 can be formed by a combination of deforming the elongate body 14 and bonding material (e.g., wear strips 22) to the elongate body. In exemplary aspects, base portions of the stabilizing projections 21 can initially be formed by deforming the elongate body 14, and wear strips 22, as further disclosed herein, can be bonded to the base portions of the stabilizing projections to fully form the stabilizing projections 21. Optionally, in aspects in which the stabilizing projections 21 are formed into the elongate body 14, the amount of additional material bonded to the elongate body can be less than embodiments in which the stabilizing projections are formed entirely by wear strips 22 without deforming the elongate body.

[0032] Referring to FIG. 5, it can be advantageous for the stabilizing projections 21 (optionally, wear strips 22), rather than the outer surface 20 of the elongate body 14 absent any stabilizing projections, to maintain contact against wall 104 of a borehole 102 (or casing) across all or substantially all of the circumference (e.g., across 360 degrees, or across at least 300 degrees, or across at least 330 degrees) of the elongate body 14. Accordingly, the helical and/or angular orientation of the stabilizing projections 21 can increase the portion of the circumference of the elongate body 14 about which each stabilizing projection extends (relative to a stabilizing projection extending parallel to the central axis 12 of the drill rod). Still further, the helical and/or angular orientation of the stabilizing projections 21 can permit (and, optionally, promote) axial fluid travel along the outer circumference of the elongate body. Said fluid travel can carry cuttings proximally (away from a drill bit). Accordingly, by providing the stabilizing projections 21 in a helical and/or angular orientation as described, the plurality of stabilizing projections can engage the wall 104 of the borehole 102 (or casing) to maintain the outer surface 20 of the elongate body 14 spaced from with the borehole (regardless of the rotational orientation of the drill rod about the central axis 12) while allowing fluid to travel axially past the stabilizing projections 21.

[0033] In various aspects, the plurality of stabilizing projections 21 can comprise three stabilizing projections, or at least three stabilizing projections, or at least four stabilizing projections, or at least five stabilizing projections or more. As further disclosed herein, it is contemplated that sequential stabilizing projections can be equally or unequally circumferentially spaced about the circumference of the elongate body, with said spacing being measured between the center points of respective stabilizing projections within a transverse plane that is perpendicular to the longitudinal axis of the elongate body.

[0034] In some aspects, in which the stabilizing projections comprise wear strips 22, the wear strips 22 can be sacrificial. That is, the wear strips 22 can be configured to wear down with use.

[0035] In some optional aspects, the plurality of wear strips 22 that at least partly define the stabilizing projections can comprise tungsten carbide. In some optional aspects, the plurality of wear strips 22 can comprise diamond (e.g., diamond particles or diamond grit). For example, in some aspects, each wear strip 22 of the plurality of wear strips can comprise a mixture of tungsten carbide and diamond particles. However, it is contemplated that other metallic and/or matrix compositions (optionally, comprising diamond particles) can be used to form the wear strips.

[0036] In some optional aspects, the plurality of wear strips 22 can comprise cladding. For example, in some optional aspects, the wear strips can be clad, via a laser, to the outer surface of the box end portion of the drill rod. In further aspects, hardfacing powder can be bonded to the outer surface of the elongate body 14 with a plasma torch. Bonded hardfacing powder can then be ground down or otherwise removed in certain locations to form a desired shape of the wear strips 22. In using a laser to clad the wear strips 22, the step of removing portions of the hardfacing powder bonded via plasma torch can be avoided, thereby increasing the amount of tungsten carbide or other material of the wear strips. Accordingly, cladding via laser can be advantageous in minimizing manufacturing time and costs. [0037] In some aspects, cladding via laser can be performed in multiple iterations at different positions along the central axis 12. Each iteration of laser cladding can extend along a portion of the circumference of the elongate body 14.

[0038] In some aspects, the stabilizing projections 21 can have a radial dimension from the portions of the outer surface of the elongate body that define the outer circumference.

Optionally, the radial dimension can be at least 0.05 inches, or from about 0.05 inches to 0.25 inches, or less than 0.2 inches, or about 1/16 inch. For example, optionally, the wear strips 22 can have a thickness (e.g., extending radially from the outer surface of the elongate body) of at least 0.05 inches, or from about 0.05 inches to 0.25 inches, or less than 0.2 inches, or about 1/16 inch. It is contemplated that the radial dimension can be optimized to centralize the drill rod in the borehole (or casing) while preventing excessive contact and drag against the borehole (or casing).

[0039] The stabilizing projections 21 (e.g., optionally, the wear strips 22) can have a length along the central axis 12 and a width along the circumference of the elongate body 12 (e.g., measured within a transverse plane that is perpendicular to the longitudinal axis of the elongate body). In some optional aspects, the width of each stabilizing projection 21 can be constant along the length of the wear strip. In further optional aspects, the width of each stabilizing projection 21 can vary along the length of the wear strip. The length of the stabilizing projection 21 can be greater than the width of the stabilizing projection. For example, in some aspects, the length of the stabilizing projection 21 can be between two and ten times the width of the stabilizing projection 21. In some optional aspects, the width of the stabilizing projection 21 can be about one eighth to one twentieth of the circumference of the drill rod. Optionally, the width of the stabilizing projection 21 can be from about 1/8 inch to about two inches, or from about inch to about one inch, or about !4 inch. In some aspects, the length of the stabilizing projection 21 can be at least one inch, or from about one inch to about five inches, or from about 1.5 to about four inches, or about two inches, or about three inches. It is contemplated that the widths of the respective stabilizing projections of the drill rod can be equal or substantially equal. However, in some aspects, it is contemplated that at least one stabilizing projection can have a width that differs from or differs by at least 15% from the width of at least one other stabilizing projection of the drill rod.

[0040] In some optional aspects, the stabilizing projections 21 can be spaced from the closest (box) end of the drill rod by at least one inch, or at least two inches, or about three inches (measured along the longitudinal axis of the elongate body). Optionally, the stabilizing projections 21 can be positioned sufficiently close to the closest (box) end of the drill rod inhibit or minimize contact of the box end portion of the drill rod 10. Optionally, the stabilizing projections 21 can be positioned adjacent to the female thread(s) along the longitudinal axis 22 to inhibit distortion of the threads from application of the stabilizing projections. In further aspects, the stabilizing projections 21 can partially or entirely overlie the female thread(s) of the box end portion.

[0041] The drill rod can have maximum diameter measured at a location axially spaced from the stabilizing projections so as not to include the dimension of the stabilizing projections in the diameter. The maximum diameter can correspond to the circumference of the drill rod. It is contemplated that the drill rod can have a maximum diameter of less than 3 inches. In various optional aspects, the drill rod 10 can have a maximum diameter of less than 5 inches, or less than 4.5 inches, or less than 4 inches, or less than 3.5 inches, or less than 3 inches, or less than 2.5 inches, or less than 2 inches.

[0042] Referring also to FIG. 5, in some aspects, a drill string 50 can comprise a plurality of drill rods 10. The plurality of drill rods can be coupled together end-to-end to form the drill string. It is contemplated that the drill rods can couple directly to each other (i.e., a pin end portion 16 of a first drill rod received within the box end portion 18 of a second drill rod) without a coupling sub or other coupling element disposed at joints between sequential drill rods. It is contemplated that such embodiments can permit performance of wireline drilling operations. The drill string 50 can further comprise a drill bit 52.

[0043] In some aspects, a method can comprise advancing the drill string 50 within a formation 100, the drill string comprising a plurality of drill rods coupled end-to-end. In some optional aspects, the plurality of stabilizing projections 21 (e.g., stabilizing projections at each joint between sequential drill rods) can prevent contact between the outer surfaces of the plurality of drill rods that are radially recessed from the stabilizing projections and a wall of a borehole (or casing) within which the drill string is positioned. In further aspects, the stabilizing projections 21 can significantly limit contact between the outer surfaces of the plurality of drill rods that are radially recessed from the stabilizing projections and the wall of the borehole (or casing). [0044] As described above, it is contemplated that the drill string can be retrieved using a wireline drilling system. The drilling system can comprise a mast, the drill string, and a drill head configured to impart rotation to the drill string within a drilling formation. In operation, the drilling system can rotate and feed the drill string into the drilling formation along a drilling axis. The drilling system can further comprise a foot clamp as is conventionally known in the art. Optionally, the foot clamp can be provided in association with a breaker and/or wrench. In exemplary aspects, the drilling system can comprise a control panel, from which drilling functions are controlled. During exploratory drilling operations, the wireline system can be configured to selectively lower and lift up a core barrel (inner tube assembly) relative to the drilling formation using a cable. As is conventional in the art, the core barrel (inner tube assembly) can collect a core sample of the drilling formation for geological analysis.

[0045] The drill bit 52 can produce cuttings in response to contact between the drill bit and the formation. At least a portion of the cuttings can travel between the plurality of stabilizing projections 21 of respective drill rods 10 of the plurality of drill rods that form the drill string.

[0046] In some aspects, a method can comprise cladding, by a laser, a plurality of wear strips to an outer surface of a box end portion of a drill rod, the drill rod having a circumference. The plurality of wear strips can be spaced about the circumference of the drill rod. Optionally, the plurality of wear strips can be cladded to the outer surface of the box end portion of the drill rod in a helical orientation.

[0047] It is contemplated that the box end can serve as a weak point for conventional drill rods. For example, having an interference coupling between adjacent drill rods can cause the box end to swell, so the outer circumference of the box end is the largest end of the drill rod. Still further, the box end can have a reduced thickness (compared to the rest of the drill rod) due to formation of threads for receiving the pin end of the adjacent drill rod. For the foregoing reasons, the box end can be particularly prone to rubbing against the wall of the borehole (or casing), which can cause heat stress and heat check cracking. In providing stabilizing projections 21 as disclosed herein, the drill rod can be centralized within the borehole (or casing) and can be less subject to flexing at the box end portion, which can reduce the deformation (e.g., helical deformation) of the drill string during drilling. That is, the stabilizing projections 21 can serve to stabilize the drill rod. Still further, the stabilizing projections (optionally, comprising wear strips 22) can reduce wear and fatigue of the elongate body 14 itself. Accordingly, in providing stabilizing projections 21 (optionally, comprising wear strips 22) at the box end portion 16 of the elongate body 14 of the drill rod 10, the lifetime of the drill rod can be increased, and the likelihood of failure (e.g., catastrophic failure) can be reduced.

EXEMPLARY ASPECTS

[0048] In view of the described products, systems, and methods and variations thereof, herein below are described certain more particularly described aspects of the invention. These particularly recited aspects should not however be interpreted to have any limiting effect on any different claims containing different or more general teachings described herein, or that the “particular” aspects are somehow limited in some way other than the inherent meanings of the language literally used therein.

[0049] Aspect 1: A drill rod having a central axis and comprising: an elongate body having a box end portion and an opposing pin end portion, the elongate body having an outer surface that defines a circumference of the elongate body, wherein the elongate body is hollow; a plurality of stabilizing projections that extend outwardly from the circumference of the elongate body, wherein the plurality of stabilizing projections are positioned proximate to the box end portion, wherein the plurality of stabilizing projections are spaced about the circumference of the elongate body.

[0050] Aspect 2: The drill rod of aspect 1, wherein the plurality of stabilizing projections comprise a plurality of wear strips that are bonded to the outer surface of the elongate body.

[0051] Aspect 3: The drill rod of aspect 2, wherein the plurality of wear strips comprise cladding.

[0052] Aspect 4: The drill rod of any one of the preceding aspects, wherein the plurality of stabilizing projections are arranged in a helical orientation.

[0053] Aspect 5: The drill rod of any one of the preceding aspects, wherein each stabilizing projection of the plurality of stabilizing projections extends along a respective centerline, wherein the respective centerline intersects a cross-sectional plane that contains the central axis of the drill rod at an acute angle.

[0054] Aspect 6: The drill rod of aspect 5, wherein the acute angle is from about 10 degrees to about 30 degrees.

[0055] Aspect 7: The drill rod of aspect 6, wherein the acute angle is about 20 degrees.

[0056] Aspect 8: The drill rod of any one of the preceding aspects, wherein the plurality of wear strips comprise tungsten carbide.

[0057] Aspect 9: The drill rod of any one of the preceding aspects, wherein the plurality of wear strips comprise diamond.

[0058] Aspect 10: The drill rod of any one of the preceding aspects, wherein the plurality of wear strips have a radial thickness of less than 0.2 inches.

[0059] Aspect 11 : The drill rod of any one of the preceding aspects, wherein the drill rod has a maximum outer diameter of less than 3 inches.

[0060] Aspect 12: The drill rod of any one of the preceding aspects, wherein the plurality of stabilizing projections are mechanically formed into the elongate body.

[0061] Aspect 13: A drill string comprising: a plurality of drill rods, wherein each drill rod of the plurality of drill rods has a central axis and comprises: an elongate body having a box end portion and an opposing pin end portion, the elongate body having an outer surface that defines a circumference of the elongate body, wherein the elongate body is hollow; and a plurality of stabilizing projections that extend outwardly from the circumference of the elongate body, wherein the plurality of stabilizing projections are positioned proximate to the box end portion, wherein the plurality of stabilizing projections are spaced about the circumference of the elongate body, and wherein the plurality of drill rods are coupled together end-to-end to form the drill string.

[0062] Aspect 14: The drill string of aspect 13, wherein the drill string does not comprise couplings at joints between sequential drill rods of the plurality of drill rods. [0063] Aspect 15: The drill string of aspect 13 or aspect 14, wherein the plurality of stabilizing projections of each drill rod of the plurality of drill rods comprise cladding.

[0064] Aspect 16: The drill string of any one of aspects 13-15, wherein the plurality of stabilizing projections of each drill rod of the plurality of drill rods comprise wear strips that are bonded to the outer surface of the elongate body of said drill rod in a helical orientation.

[0065] Aspect 17: The drill string of any one of aspects 13-16, wherein each stabilizing projection of the plurality of stabilizing projections of each drill rod of the plurality of drill rods extends along a respective centerline, wherein the respective centerline intersects a cross-sectional plane that contains the central axis of a respective drill rod at an acute angle.

[0066] Aspect 18: The drill string of aspect 17, wherein the acute angle is from about 10 degrees to about 30 degrees.

[0067] Aspect 19: The drill string of aspect 18, wherein the acute angle is about 20 degrees.

[0068] Aspect 20: The drill string of any one of aspects 13-19, wherein the plurality of stabilizing projections of each drill rod of the plurality of drill rods comprise tungsten carbide.

[0069] Aspect 21: The drill string of any one of aspects 13-20, wherein the plurality of stabilizing projections of each drill rod of the plurality of drill rods comprise diamond.

[0070] Aspect 22: The drill string of any one of aspects 13-21, wherein the plurality of stabilizing projections of each drill rod of the plurality of drill rods have a radial dimension of less than 0.2 inches.

[0071] Aspect 23: The drill string of any one of aspects 13-22, wherein each drill rod has a maximum outer diameter of less than 3 inches.

[0072] Aspect 24: A method comprising: advancing a drill string within a formation, the drill string comprising a plurality of drill rods coupled end-to-end, wherein each drill rod of the plurality of drill rods has a central axis and comprises: an elongate body having a box end portion and an opposing pin end portion, the elongate body having an outer surface that defines a circumference of the elongate body, wherein the elongate body is hollow; and a plurality of stabilizing projections that extend outwardly from the circumference of the elongate body, wherein the plurality of stabilizing projections are positioned proximate to the box end portion, wherein the plurality of stabilizing projections are spaced about the circumference of the elongate body.

[0073] Aspect 25: The method of aspect 24, wherein the plurality of stabilizing projections prevent contact between outer surfaces of the plurality of drill rods that are radially recessed from the stabilizing projections and a wall of a borehole within which the drill string is positioned.

[0074] Aspect 26: The method of aspect 24 or aspect 25, wherein the drill string further comprises a drill bit at a distal end of the drill string, wherein the drill bit produces cuttings in response to contact between the drill bit and the formation, and wherein a portion of the cuttings travels between the plurality of stabilizing projections of respective drill rods of the plurality of drill rods.

[0075] Aspect 27: The method of any one of aspects 23-25, wherein the drill string does not comprise couplings at joints between sequential drill rods of the plurality of drill rods.

[0076] Aspect 28: A method comprising: cladding, by a laser, a plurality of wear strips to an outer surface of a box end portion of a drill rod, the drill rod having a circumference, wherein the plurality of wear strips are spaced about the circumference of the drill rod.

[0077] Aspect 29: The method of aspect 28, wherein the plurality of wear strips are cladded to the outer surface of the box end portion of the drill rod in a helical orientation.

[0078] Aspect 20: A method comprising: plastically deforming an elongate body to form a plurality of stabilizing projections, the elongate body having a box end portion and an opposing pin end portion, the elongate body having an outer surface that defines a circumference of the elongate body, wherein plurality of stabilizing projections extend outwardly from the circumference of the elongate body, wherein the plurality of stabilizing projections are positioned proximate to the box end portion, wherein the plurality of stabilizing projections are spaced about the circumference of the elongate body. [0079] Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, certain changes and modifications may be practiced within the scope of the appended aspects.

Claims

CLAIMS What is claimed is:

1. A drill rod having a central axis and comprising: an elongate body having a box end portion and an opposing pin end portion, the elongate body having an outer surface that defines a circumference of the elongate body, wherein the elongate body is hollow; and a plurality of stabilizing projections that extend outwardly from the circumference of the elongate body, wherein the plurality of stabilizing projections are positioned proximate to the box end portion, wherein the plurality of stabilizing projections are spaced about the circumference of the elongate body.

2. The drill rod of claim 1, wherein the plurality of stabilizing projections comprise a plurality of wear strips that are bonded to the outer surface of the elongate body.

3. The drill rod of claim 2, wherein the plurality of wear strips comprise cladding.

4. The drill rod of claim 1, wherein the plurality of stabilizing projections are arranged in a helical orientation.

5. The drill rod of claim 1, wherein each stabilizing projection of the plurality of stabilizing projections extends along a respective centerline, wherein the respective centerline intersects a cross-sectional plane that contains the central axis of the drill rod at an acute angle.

6. The drill rod of claim 5, wherein the acute angle is from about 10 degrees to about 30 degrees.

7. The drill rod of claim 6, wherein the acute angle is about 20 degrees.

8. The drill rod of claim 2, wherein the plurality of wear strips comprise tungsten carbide.

9. The drill rod of claim 2, wherein the plurality of wear strips comprise diamond.

10. The drill rod of claim 2, wherein the plurality of wear strips have a radial thickness of less than 0.2 inches.

11. The drill rod of claim 1, wherein the drill rod has a maximum outer diameter of less than 3 inches.

12. The drill rod of claim 1, wherein the plurality of stabilizing projections are mechanically formed into the elongate body.

13. A drill string comprising: a plurality of drill rods, wherein each drill rod of the plurality of drill rods has a central axis and comprises: an elongate body having a box end portion and an opposing pin end portion, the elongate body having an outer surface that defines a circumference of the elongate body, wherein the elongate body is hollow; and a plurality of stabilizing projections that extend outwardly from the circumference of the elongate body, wherein the plurality of stabilizing projections are positioned proximate to the box end portion, wherein the plurality of stabilizing projections are spaced about the circumference of the elongate body, and wherein the plurality of drill rods are coupled together end-to-end to form the drill string.

14. The drill string of claim 13, wherein the drill string does not comprise couplings at joints between sequential drill rods of the plurality of drill rods.

15. The drill string of claim 13, wherein the plurality of stabilizing projections of each drill rod of the plurality of drill rods comprise cladding.

16. The drill string of claim 13, wherein the plurality of stabilizing projections of each drill rod of the plurality of drill rods comprise wear strips that are bonded to the outer surface of the elongate body of said drill rod in a helical orientation.

17. The drill string of claim 13, wherein each stabilizing projection of the plurality of stabilizing projections of each drill rod of the plurality of drill rods extends along a respective centerline, wherein the respective centerline intersects a cross-sectional plane that contains the central axis of a respective drill rod at an acute angle.

18. The drill string of claim 17, wherein the acute angle is from about 10 degrees to about 30 degrees.

19. The drill string of claim 18, wherein the acute angle is about 20 degrees.

20. The drill string of claim 13, wherein the plurality of stabilizing projections of each drill rod of the plurality of drill rods comprise tungsten carbide.

21. The drill string of claim 13, wherein the plurality of stabilizing projections of each drill rod of the plurality of drill rods comprise diamond.

22. The drill string of claim 13, wherein the plurality of stabilizing projections of each drill rod of the plurality of drill rods have a radial dimension of less than 0.2 inches.

23. The drill string of claim 13, wherein each drill rod has a maximum outer diameter of less than 3 inches.

24. A method comprising: advancing a drill string within a formation, the drill string comprising a plurality of drill rods coupled end-to-end, wherein each drill rod of the plurality of drill rods has a central axis and comprises: an elongate body having a box end portion and an opposing pin end portion, the elongate body having an outer surface that defines a circumference of the elongate body, wherein the elongate body is hollow; and a plurality of stabilizing projections that extend outwardly from the circumference of the elongate body, wherein the plurality of stabilizing projections are positioned proximate to the box end portion, wherein the plurality of stabilizing projections are spaced about the circumference of the elongate body.

25. The method of claim 24, wherein the plurality of stabilizing projections prevent contact between outer surfaces of the plurality of drill rods that are radially recessed from the stabilizing projections and a wall of a borehole within which the drill string is positioned.

26. The method of claim 24, wherein the drill string further comprises a drill bit at a distal end of the drill string, wherein the drill bit produces cuttings in response to contact between the drill bit and the formation, and wherein a portion of the cuttings travels between the plurality of stabilizing projections of respective drill rods of the plurality of drill rods.

27. The method of claim 24, wherein the drill string does not comprise couplings at joints between sequential drill rods of the plurality of drill rods.

28. A method comprising:

19 cladding, by a laser, a plurality of wear strips to an outer surface of a box end portion of a drill rod, the drill rod having a circumference, wherein the plurality of wear strips are spaced about the circumference of the drill rod.

29. The method of claim 28, wherein the plurality of wear strips are cladded to the outer surface of the box end portion of the drill rod in a helical orientation.

20