(19)
(11) EP 0 350 045 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
06.06.1990 Bulletin 1990/23

(43) Date of publication A2:
10.01.1990 Bulletin 1990/02

(21) Application number: 89112388.7

(22) Date of filing: 06.07.1989
(51) International Patent Classification (IPC)5: E21B 10/56
(84) Designated Contracting States:
BE DE GB

(30) Priority: 06.07.1988 US 215499

(71) Applicant: BAKER-HUGHES INCORPORATED
Houston Texas 77027-5115 (US)

(72) Inventor:
  • Jürgens, Rainer Dr.
    D-3100 Celle (DE)

(74) Representative: Busse & Busse Patentanwälte 
Postfach 12 26
49002 Osnabrück
49002 Osnabrück (DE)


(56) References cited: : 
   
     
    Remarks:
    The title of the invention has been amended (Guidelines for Examination in the EPO, A-III, 7.3).
     


    (54) Drill bit with composite cutting members


    (57) Drill bits may include cutting members which have cutting faces formed of segments of differing cutting materials. The faces of the cutting members may include two or more segments, with the segments formed from at least two different materials. For example, a first segment could be formed of a polycrystalline diamond compact surface while a second segment could be formed of a thermally stable diamond product material.







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