(19)

(11)

EP 0 898 638 A1

(12)

(43) Date of publication: 03.03.1999 Bulletin 1999/09 (21) Application number: 97920827.0 (22) Date of filing: 02.05.1997

(51) International Patent Classification (IPC):  E21B 17/ 22( . ) E21B 31/ 03( . ) E21B 31/ 00( . ) E21B 37/ 02( . ) (86) International application number: PCT/GB1997/001219 (87) International publication number: WO 1997/043517 (20.11.1997 Gazette 1997/50)

(84) Designated Contracting States: FR NL (30) Priority: 09.05.1996 GB 19960009706 (71) Applicant: The Red Baron (Oil Tools Rental) Limited Altens Aberdeen AB1 4PG (GB)	(72) Inventor: BRUCE, Ronald, James Aberdeen AB31 4QB (GB) (74) Representative: Goodenough, Nigel, et al  A.A. Thornton & Co. Northumberland House 303-306 High Holborn London WC1V 7LE London WC1V 7LE (GB)