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(11)

EP 2 013 442 A1

(12)

(43) Date of publication: 14.01.2009 Bulletin 2009/03 (21) Application number: 07733614.7 (22) Date of filing: 13.04.2007

(51) International Patent Classification (IPC):  E21B 19/087(2006.01) E21B 19/06(2006.01) E21B 19/16(2006.01) (86) International application number: PCT/GB2007/050192 (87) International publication number: WO 2007/125359 (08.11.2007 Gazette 2007/45)

(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 LV MC MT NL PL PT RO SE SI SK TR Designated Extension States: AL BA HR MK RS (30) Priority: 28.04.2006 US 414511 (71) Applicant: National Oilwell Varco, L.P. Houston, TX 77036 (US)	(72) Inventors: MASON, David Brian Anaheim, California 92807 (US) DEKKER, Pieter 4435 Ak Baarland (NL) MULDER, Rene 4873 DM Etten-Leur (NL) KRIJNEN, Antonius Dimphena Maria 4791 SJ Klundert (NL) (74) Representative: Lucas, Brian Ronald  Lucas & Co. 135 Westhall Road GB-Warlingham, Surrey CR6 9HJ GB-Warlingham, Surrey CR6 9HJ (GB)