(19)

(11)

EP 1 181 435 A1

(12)

(43) Date of publication: 27.02.2002 Bulletin 2002/09 (21) Application number: 00932786.7 (22) Date of filing: 25.05.2000

(51) International Patent Classification (IPC)7: E21B 47/01, E21B 47/12 (86) International application number: PCT/US0014/464 (87) International publication number: WO 0073/625 (07.12.2000 Gazette 2000/49)

(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 MK RO SI (30) Priority: 28.05.1999 US 136656 P (71) Applicant: BAKER HUGHES INCORPORATED Houston Texas 77027 (US)	(72) Inventors: ARONSTAM, Peter, S. Houston, TX 77042 (US) BERGER, Per-Erik N-4152 Vestre Amoy (NO) (74) Representative: Pacitti, Paolo et al Murgitroyd and Company 165-169 Scotland Street Glasgow G5 8PL Glasgow G5 8PL (GB)