(19)

(11)

EP 2 126 269 A1

(12)

(43) Date of publication: 02.12.2009 Bulletin 2009/49 (21) Application number: 08709632.7 (22) Date of filing: 20.02.2008

(51) International Patent Classification (IPC):  E21B 3/02(2006.01) (86) International application number: PCT/GB2008/050112 (87) International publication number: WO 2008/102175 (28.08.2008 Gazette 2008/35)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR (30) Priority: 22.02.2007 US 902798 P 04.02.2008 US 12616 (71) Applicant: National Oilwell Varco, L.P. Houston, TX 77036 (US)	(72) Inventor: STUBSTAD, Svein Houston, Texas 77057 (US) (74) Representative: Lucas, Brian Ronald  Lucas & Co. 135 Westhall Road Warlingham Surrey CR6 9HJ Warlingham Surrey CR6 9HJ (GB)