(19)
(11) EP 0 835 360 A1

(12)

(43) Date of publication:
15.04.1998 Bulletin 1998/16

(21) Application number: 96923945.0

(22) Date of filing: 26.06.1996
(51) International Patent Classification (IPC): 
E21B 17/ 07( . )
 E21B 44/ 00( . )
(86) International application number:
PCT/EP1996/002798
(87) International publication number:
WO 1997/001693 (16.01.1997 Gazette 1997/04)
(84) Designated Contracting States:
DE FR GB

(30) Priority: 27.06.1995 EP 19950201736

(71) Applicant: SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V.
2596 HR Den Haag (NL)

(72) Inventor:
  • VAN DEN STEEN, Leon
    NL-2288 GD Rijswijk (NL)

   


(54) HYDRAULIC THRUSTER FOR USE IN A DRILL STRING