(19)

(11)

EP 1 075 586 A1

(12)

(43) Date of publication: 14.02.2001 Bulletin 2001/07 (21) Application number: 99920955.4 (22) Date of filing: 04.05.1999

(51) International Patent Classification (IPC)7: E21B 37/00, E21B 4/02, B08B 9/04 (86) International application number: PCT/GB9901/371 (87) International publication number: WO 9957/416 (11.11.1999 Gazette 1999/45)

(84) Designated Contracting States: GB NL (30) Priority: 02.05.1998 GB 9809411 (71) Applicant: Rotech Holdings Limited Aberdeen AB2 6HQ (GB)	(72) Inventors: VAN DRENTHAM-SUSMAN, Hector, Fillippus, Alexander Aberdeen AB32 6NL (GB) STEWART, Kenneth, Roderick Aberdeen AB2 6AS (GB) (74) Representative: Szczuka, Jan Tymoteusz  Cruikshank & Fairweather19 Royal Exchange Square Glasgow G1 3AEScotland Glasgow G1 3AEScotland (GB)