(19)

(11)

EP 0 862 679 A1

(12)

(43) Date of publication: 09.09.1998 Bulletin 1998/37 (21) Application number: 96939995.0 (22) Date of filing: 25.11.1996

(51) International Patent Classification (IPC):  E21B 4/ 00( . ) E21B 17/ 02( . ) E21B 23/ 04( . ) E21B 4/ 18( . ) E21B 17/ 05( . ) E21B 31/ 18( . ) (86) International application number: PCT/GB1996/002902 (87) International publication number: WO 1997/019248 (29.05.1997 Gazette 1997/23)

(84) Designated Contracting States: FR GB NL (30) Priority: 23.11.1995 GB 19950023978 08.07.1996 GB 19960014309 (71) Applicant: The Red Baron (Oil Tools Rental) Limited Altens Aberdeen AB1 4PG (GB)	(72) Inventors: McGARIAN, Bruce Aberdeen AB3 2HW (GB) TULLOCH, Rory, McGrae Aberdeen AB1 6SF (GB) (74) Representative: Goodenough, Nigel  A.A. Thornton & Co. Northumberland House 303-306 High Holborn London WC1V 7LE London WC1V 7LE (GB)