(19)

(11)

EP 1 297 244 A1

(12)

(43) Date of publication: 02.04.2003 Bulletin 2003/14 (21) Application number: 00939969.2 (22) Date of filing: 20.06.2000

(51) International Patent Classification (IPC)7: E21B 44/00 (86) International application number: PCT/US0016/922 (87) International publication number: WO 0109/8631 (27.12.2001 Gazette 2001/52)

(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: BAKER HUGHES INCORPORATED HoustonTexas 77027 (US)	(72) Inventors: FLEET, Alan N. Aberdeen AB22 1RN (GB) SLEEMAN, Derek, H. Aberdeen AB24 1RN (GB) PREECE, Alun D. Aberdeenshire AB32 6WE (GB) (74) Representative: Holmes, Matthew Peter et al MARKS & CLERK,Sussex House,83-85 Mosley Street Manchester M2 3LG Manchester M2 3LG (GB)