EP0145422A2 - Drehbohrmeissel - Google Patents

Drehbohrmeissel Download PDF

Info

Publication number
EP0145422A2
EP0145422A2 EP84308323A EP84308323A EP0145422A2 EP 0145422 A2 EP0145422 A2 EP 0145422A2 EP 84308323 A EP84308323 A EP 84308323A EP 84308323 A EP84308323 A EP 84308323A EP 0145422 A2 EP0145422 A2 EP 0145422A2
Authority
EP
European Patent Office
Prior art keywords
carrier
drill bit
backing layer
cutting
bit body
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP84308323A
Other languages
English (en)
French (fr)
Other versions
EP0145422A3 (de
Inventor
Michael Thomas Wardley
John Denzil Barr
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NL Petroleum Products Ltd
Original Assignee
NL Petroleum Products Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB838332343A external-priority patent/GB8332343D0/en
Priority claimed from GB848405179A external-priority patent/GB8405179D0/en
Application filed by NL Petroleum Products Ltd filed Critical NL Petroleum Products Ltd
Publication of EP0145422A2 publication Critical patent/EP0145422A2/de
Publication of EP0145422A3 publication Critical patent/EP0145422A3/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/46—Drill bits characterised by wear resisting parts, e.g. diamond inserts
    • E21B10/56—Button-type inserts
    • E21B10/567—Button-type inserts with preformed cutting elements mounted on a distinct support, e.g. polycrystalline inserts

Definitions

  • the invention relates to rotary drill bits for use in drilling or coring deep holes in subsurface formations and, in particular, to the mounting of cutting elements on such bits.
  • Rotary drill bits of the kind to which the invention relates comprise a bit body having a shank and an inner channel for supplying drilling fluid to the face of the bit.
  • the bit body carries a plurality of so-called "preform" cutting elements.
  • Each cutting element comprises a thin hard facing layer, which defines the front cutting face of the element, bonded to a less hard backing layer.
  • the hard facing layer may be formed of polycrystalline diamond or other superhard material
  • the backing layer may be formed of cemented tungsten carbide.
  • the two-layer arrangement of the cutting elements provides a degree of self-sharpening since, in use, the less hard backing layer wears away more easily than the harder cutting layer.
  • the preform cutting elements are mounted on the bit body by being bonded, for example by brazing, to a carrier which may be in the form of a stud which is received and located in a socket in the bit body.
  • a carrier which may be in the form of a stud which is received and located in a socket in the bit body.
  • Such studs have been formed of various materials.
  • these studs have been formed from hardened steel.
  • such arrangements suffer from the severe disadvantage that exposed portions of the steel stud are subject to erosion during use of the bit, such erosion being caused, generally, by the flow over the surface of the bit of drilling fluid carrying drilling debris.
  • Such erosion can occur very rapidly and can progress to the stage where the mounting of the cutting elements is so weakened by erosion that the bit becomes unusable, even though the cutting elements themselves may not have reached the end of their working life due to the wear caused by drilling.
  • the present invention sets out to overcome the disadvantages of the above-mentioned known arrangements.
  • a rotary drill bit for use in drilling or coring deep holes in subsurface formations comprising a bit body having a shank for connection to a drill string, a plurality of cutting elements mounted at the surface of the bit body, and a channel in the bit body for supplying drilling fluid to the surface of the bit body for cooling and/or cleaning the cutting elements, at least some of the cutting elements each comprising a thin hard facing layer, defining a front cutting face, bonded to a less hard backing layer, the cutting element being mounted on a carrier which is received in a socket in the bit body in such manner that, at least before any wear of the bit has occurred, the carrier is substantially wholly shrouded by the material of the bit body, the carrier being formed from material which is less hard than said backing layer of the cutting element.
  • the carrier Since the carrier is initially shrouded by the material of the bit body it is not directly subjected to erosion during operation of the bit. As the cutting elements wear down, however, the backing layer and bit body to the rear of the cutting face wear down, eventually exposing part of the carrier, but since the carrier is exposed only due to wear, and not to erosion, it follows that any exposed surface of the carrier, during drilling, is in rubbing contact with the surface of the formation and is not therefore subject to erosion by drilling fluid. Since this exposed portion of the carrier is of less hard material than the backing layer of the cutting element, the self-sharpening effect of the whole cutting member is improved, since the softer carrier wears away at a faster rate than either the hard facing or the backing material.
  • each carrier may be formed from steel, and, as previously mentioned, steel carriers are less expensive to produce than carriers from harder material, such as cemented tungsten carbide.
  • the material of the carrier it is preferable for the material of the carrier to be less hard than the material from which the bit body is formed, although this is not essential.
  • the hard facing layer of each cutting element may be formed of polycrystalline diamond and the backing layer may be formed of cemented tungsten carbide.
  • the backing layer of each cutting element may be of non-uniform thickness, being thicker adjacent the cutting edge of the facing layer than it is over the rest of the area of the facing layer.
  • the thickness of the backing layer may vary continuously and smoothly across the area of the cutting face.
  • the rear surface of the backing layer is substantially flat so that the backing layer is generally wedge-shaped in cross-section.
  • Each cutting element may be substantially circular in cross-section, in known manner, although other shapes of cutting element may be employed.
  • the carrier may be of similar cross-section to the associated cutting element and may form an axial extension thereof.
  • the carrier may be in the form of a generally cylindrical stud having a surface inclined at less than 90° to the central axis of the stud and to which the rear surface of the backing layer is bonded.
  • the bit body may be formed from cemented tungsten carbide matrix, steel, or steel formed with a hard coating, or any conventional combination of such materials.
  • Each carrier may be secured within its associated socket by brazing or it may be an interference fit in the socket.
  • Figure 2 is an end elevation of the drill bit shown in Figure 1
  • Figures 3 to 6 are diagrammatic sections through cutting elements mounted on a carrier in a drill bit body.
  • the body 10 of the drill bit is typically formed of tungsten carbide matrix infiltrated with a binder alloy, and has a threaded shank 11 at one end for connection to the drill string.
  • the operative end face 12 of the bit body is formed with anumber of blades 13 radiating from the central area of the bit and the blades carry cutting members 14 spaced apart along the length thereof.
  • the bit has a gauge section 15 including kickers 16 which contact the walls of the bore hole to stabilise the bit in the bore hole.
  • a central channel (not shown) in the bit body and shank delivers drilling fluid through nozzles 17 in the end face 12, in known manner.
  • Each cutting member 14 comprises a preform cutting element mounted on a carrier in the form of a stud which is located in a socket in the bit body.
  • each preform cutting element is usually circular and comprises a thin facing layer of polycrystalline diamond bonded to a thicker backing layer of tungsten carbide.
  • the rear surface of the backing layer of each cutting element is bonded, for example by brazing, to a suitably orientated surface on the stud.
  • Figures 3 to 6 show, by way of example only, four typical arrangements of cutting member according to the invention.
  • the stud is formed from a material which is less hard than the material, usually tungsten carbide, of the backing layer.
  • the cutting element 18 itself is circular and comprises a thin hard facing layer 19 of polycrystalline diamond and a thicker backing layer 20 of cemented tungsten carbide.
  • the facing layer 19 extends at right angles to the central axis of the cutting element.
  • the rear surface 21 of the backing layer 20 is bonded to the end face of a generally cylindrical stud 22, formed from steel, which is coaxial with the cutting element 18 and of similar cross-section, so as to form an axial extension of the cutting element.
  • the cutting member 14 as a whole is received in a cylindrical socket 23 which is formed in the blade 13 of the bit body, the blade being formed from tungsten carbide matrix.
  • the stud 22 may be secured within the socket by brazing or may be an interference fit. As shown in Figure 3, however, the depth of the socket 23 in relation to the axial length of the stud 22 is such that the stud portion of the cutting member is wholly received within the socket so that the material of the stud is wholly shrouded by the matrix material forming the bit body.
  • this arrangement protects the steel stud from the erosion to which it would otherwise be subject.
  • the thin layer of matrix at the lower part of the socket becomes worn away so that the material of the stud 22 itself rubs on the formation.
  • This enhances the self-sharpening effect of the cutting member since the softer material of the stud 22 will wear away more quickly than the harder material of the backing layer 20 which, in turn, wears away more quickly than the facing layer 19.
  • the only exposed portion of the stud 22 is in rubbing contact with the formation, the remainder of the stud is still protected from erosion.
  • the backing layer 20 is not of uniform thickness, but the rear surface 21 of the backing layer is inclined at an angle of less than 90 o to the central axis of the cutting element.
  • the backing layer 20 is thus generally wedge-shaped so as to be of increased thickness adjacent the cutting edge of the cutting element, which is indicated at 24.
  • the front surface of the steel stud 22 is similarly inclined to the central axis of the stud so that it registers with the rear surface of the backing layer 20, the two surfaces being bonded together, before the stud is inserted in the socket 23, by a high temperature bonding process, such as L S bonding.
  • a high temperature bonding process such as L S bonding.
  • the dimensions of the socket 23 are such that the stud is wholly received in the socket so as to be protected from erosion during use of the bit.
  • Figures 5 and 6 show further alternative arrangements with different configurations of stud, the stud in each case again being wholly shrouded by the material of the bit body.
  • the cutting members each comprising the preform cutting element 18 and carrier 22, will normally be pre-assembled by bonding the cutting elements to the carriers before insertion in the sockets in the bit body.
  • the invention also includes within its scope arrangements where the carriers are mounted in the bit body before the cutting elements are bonded to the carriers.
  • the carriers may be cast in the bit body during formation of the bit body, or may be brazed into the sockets subsequently, the cutting elements in each case then being bonded to the carriers, for example by laser bonding, while the carriers are in situ.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Geology (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Earth Drilling (AREA)
  • Excavating Of Shafts Or Tunnels (AREA)
  • Holo Graphy (AREA)
  • Surgical Instruments (AREA)
  • Drilling Tools (AREA)
EP84308323A 1983-12-03 1984-11-30 Drehbohrmeissel Withdrawn EP0145422A3 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB8332343 1983-12-03
GB838332343A GB8332343D0 (en) 1983-12-03 1983-12-03 Rotary drill bits
GB848405179A GB8405179D0 (en) 1984-02-28 1984-02-28 Rotary drill bits
GB8405179 1984-02-28

Publications (2)

Publication Number Publication Date
EP0145422A2 true EP0145422A2 (de) 1985-06-19
EP0145422A3 EP0145422A3 (de) 1986-05-28

Family

ID=26287070

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84308323A Withdrawn EP0145422A3 (de) 1983-12-03 1984-11-30 Drehbohrmeissel

Country Status (5)

Country Link
EP (1) EP0145422A3 (de)
AU (1) AU3592584A (de)
BR (1) BR8406134A (de)
GB (1) GB2151283B (de)
NO (1) NO844770L (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0332474A1 (de) * 1988-03-11 1989-09-13 Camco Drilling Group Limited Zusammenstellung von Schneideinsätzen für Drehbohrmeissel
AU588677B2 (en) * 1986-03-24 1989-09-21 Smith International, Inc. Expandable diamond drag bit

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU578637B2 (en) * 1983-12-03 1988-11-03 N.L. Petroleum Products Ltd. Rotary drill bits and cutting elements for such bits
GB8418481D0 (en) * 1984-07-19 1984-08-22 Nl Petroleum Prod Rotary drill bits
US4781256A (en) * 1984-12-14 1988-11-01 Nl Petroleum Products Limited Cutting structures for rotary drill bits
GB8431633D0 (en) * 1984-12-14 1985-01-30 Nl Petroleum Prod Cutting structures for rotary drill bits
US4694918A (en) * 1985-04-29 1987-09-22 Smith International, Inc. Rock bit with diamond tip inserts
AU577958B2 (en) * 1985-08-22 1988-10-06 De Beers Industrial Diamond Division (Proprietary) Limited Abrasive compact
US4730682A (en) * 1985-12-23 1988-03-15 Ingersoll-Rand Company Erosion resistant rock drill bit
US5111895A (en) * 1988-03-11 1992-05-12 Griffin Nigel D Cutting elements for rotary drill bits
GB2218131B (en) * 1988-05-06 1992-03-25 Reed Tool Co Improvements in or relating to rotary drill bits
DE69006867T2 (de) * 1989-02-14 1994-10-13 Camco Drilling Group Ltd Schneidelemente für Drehbohrmeissel.
GB2273306B (en) * 1992-12-10 1996-12-18 Camco Drilling Group Ltd Improvements in or relating to cutting elements for rotary drill bits

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2719330C3 (de) * 1977-04-30 1984-01-05 Christensen, Inc., 84115 Salt Lake City, Utah Drehbohrmeißel
US4244432A (en) * 1978-06-08 1981-01-13 Christensen, Inc. Earth-boring drill bits
EP0032428B1 (de) * 1980-01-10 1986-08-27 Stonehouse U.K. Limited Drehbohrmeissel
US4593777A (en) * 1983-02-22 1986-06-10 Nl Industries, Inc. Drag bit and cutters

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU588677B2 (en) * 1986-03-24 1989-09-21 Smith International, Inc. Expandable diamond drag bit
EP0332474A1 (de) * 1988-03-11 1989-09-13 Camco Drilling Group Limited Zusammenstellung von Schneideinsätzen für Drehbohrmeissel
US4947945A (en) * 1988-03-11 1990-08-14 Reed Tool Company Limited Relating to cutter assemblies for rotary drill bits

Also Published As

Publication number Publication date
GB2151283A (en) 1985-07-17
GB2151283B (en) 1987-04-08
BR8406134A (pt) 1985-09-24
NO844770L (no) 1985-06-04
EP0145422A3 (de) 1986-05-28
GB8430291D0 (en) 1985-01-09
AU3592584A (en) 1985-06-06

Similar Documents

Publication Publication Date Title
EP0169683B1 (de) Drehbohrmeissel
US4823892A (en) Rotary drill bits
US5732784A (en) Cutting means for drag drill bits
CA1237121A (en) Rotary drill bits and cutting elements for such bits
US4951762A (en) Drill bit with cemented carbide inserts
US4682663A (en) Mounting means for cutting elements in drag type rotary drill bit
US8783387B2 (en) Cutter geometry for high ROP applications
US7909119B2 (en) Drill bits with notches and enclosed slots
US9284790B2 (en) Innovative cutting element and cutting structure using same
US6823952B1 (en) Structure for polycrystalline diamond insert drill bit body
US4907662A (en) Rotary drill bit having improved mounting means for multiple cutting elements
EP1096103A1 (de) Bi-zentrales Bohrzeug zum Bohren durch Verrohrungsschuh
EP0592210B1 (de) Schneidelement für Drehbohr-Fräsmeissel
EP0246789A2 (de) Schneidelement für einen Drehbohrmeissel, Drehbohrmeissel mit derartigem Schneidelement und dessen Herstellungsverfahren
EP0687799A1 (de) Verbesserungen an oder bezüglich, mit einem superharten Material bekleideten, Elementen
EP0291314A2 (de) Schneidelement und Drehbohrmeissel mit einem derartigen Element
US20080156545A1 (en) Method, System, and Apparatus of Cutting Earthen Formations and the like
EP0145422A2 (de) Drehbohrmeissel
EP0643194B1 (de) Asymmetrisches Schneidelement aus PDC für einen Bohrmeissel
EP0186408B1 (de) Schneidelement für Drehbohrmeissel
US4830123A (en) Mounting means for cutting elements in drag type rotary drill bit
US4898252A (en) Cutting structures for rotary drill bits
EP0605151A1 (de) Drehbohrmeissel mit Stabilisierungselementen
GB2314360A (en) Cutter assembly for rock bits with back support groove
WO1999028589A1 (en) Continuous self-sharpening cutting assembly for use with drilling systems

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): BE CH DE FR LI NL SE

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): BE CH DE FR LI NL SE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19870129

RIN1 Information on inventor provided before grant (corrected)

Inventor name: WARDLEY, MICHAEL THOMAS

Inventor name: BARR, JOHN DENZIL