(19)

(11)

EP 1 328 706 A1

(12)

(43) Date of publication: 23.07.2003 Bulletin 2003/30 (21) Application number: 00975347.6 (22) Date of filing: 23.10.2000

(51) International Patent Classification (IPC)7: E21B 43/12 (86) International application number: PCT/US0029/267 (87) International publication number: WO 0203/5060 (02.05.2002 Gazette 2002/18)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE Designated Extension States: AL LT LV MK RO SI (71) Applicant: Valence Operating Company Kingwood, TX 77339 (US)	(72) Inventor: AVERHOFF, Jon R. Kingwood, TX 77339 (US) (74) Representative: Frankland, Nigel Howard  FORRESTER & BOEHMERTPettenkoferstrasse 20-22 80336 München 80336 München (DE)