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EP 1 766 181 A1

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(43) Date of publication: 28.03.2007 Bulletin 2007/13 (21) Application number: 05752490.2 (22) Date of filing: 17.06.2005

(51) International Patent Classification (IPC):  E21B 21/06(2006.01) E21B 41/00(2006.01) (86) International application number: PCT/GB2005/050091 (87) International publication number: WO 2005/124096 (29.12.2005 Gazette 2005/52)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU MC NL PL PT RO SE SI SK TR (30) Priority: 22.06.2004 US 875083 (71) Applicant: Varco I/P, Inc. Houston TX 77042-4200 (US)

(72) Inventors: BURNETT, George Alexander Aberdeen, Aberdeenshire AB10 7JR (GB) WOOD, David Welshpool Eastern Oil Tools Welshpool Western Australia 6106 (AU) SEYFFERT, Kenneth Wayne Houston, Texas 77018 (US) HERBEN, William Christian Magnolia, Texas 77355 (US) MCINTOSH, James Michael The Woodlands, Texas 77385 (US) CRABB, Colin Arbroath DD11 2LZ (GB) (74) Representative: Lucas, Phillip Brian et al Lucas & Co. 135 Westhall Road Warlingham, Surrey CR6 9HJ Warlingham, Surrey CR6 9HJ (GB)