(19)

(11)

EP 1 488 073 A1

(12)

(43) Date of publication: 22.12.2004 Bulletin 2004/52 (21) Application number: 03742832.3 (22) Date of filing: 19.02.2003

(51) International Patent Classification (IPC)7: E21B 21/08, E21B 44/00 (86) International application number: PCT/US2003/005012 (87) International publication number: WO 2003/071091 (28.08.2003 Gazette 2003/35)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT SE SI SK TR Designated Extension States: AL LT LV MK RO (30) Priority: 20.02.2002 US 358226 P (71) Applicant: Shell Internationale Research Maatschappij B.V. 2596 HR The Hague (NL)	(72) Inventor: VAN RIET, Egbert, Jan NL-2288 GD Rijswijk (NL)