(19)

(11)

EP 0 848 783 A2

(12)

(43) Date of publication: 24.06.1998 Bulletin 1998/26 (21) Application number: 96929449.0 (22) Date of filing: 09.09.1996

(51) International Patent Classification (IPC):  E21B 23/ 01( . ) E21B 23/ 04( . ) (86) International application number: PCT/GB1996/002214 (87) International publication number: WO 1997/009510 (13.03.1997 Gazette 1997/12)

(84) Designated Contracting States: FR NL (30) Priority: 08.09.1995 GB 19950018352 (71) Applicant: The Red Baron (Oil Tools Rental) Limited Altens Aberdeen AB1 4PG (GB)	(72) Inventors: McGARIAN, Bruce Stonehaven Aberdeen AB3 2HW (GB) SIMPSON, Neil, Andrew, Abercrombie Downies Portlethen Aberdeen AB1 4QX (GB) (74) Representative: Goodenough, Nigel, et al  A.A. Thornton & Co. Northumberland House 303-306 High Holborn London WC1V 7LE London WC1V 7LE (GB)