(19)

(11)

EP 1 060 323 A1

(12)

(43) Date of publication: 20.12.2000 Bulletin 2000/51 (21) Application number: 97950521.1 (22) Date of filing: 24.12.1997

(51) International Patent Classification (IPC)7: E21B 21/00 (86) International application number: PCT/NL9700/726 (87) International publication number: WO 9934/091 (08.07.1999 Gazette 1999/27)

(84) Designated Contracting States: AT DE DK GB Designated Extension States: AL RO (71) Applicant: Well Engineering Partners B.V. 9481 AE Vries (NL)	(72) Inventors: VAN WECHEM, Gustaaf, Louis NL-2811 RD Reeuwijk (NL) BAKKER, Thomas, Walburgis NL-9481 AE Vries (NL) (74) Representative: Prins, Adrianus Willem et al Vereenigde,Nieuwe Parklaan 97 2587 BN Den Haag 2587 BN Den Haag (NL)