(19)

(11)

EP 1 727 960 A1

(12)

(43) Date of publication: 06.12.2006 Bulletin 2006/49 (21) Application number: 05729603.0 (22) Date of filing: 24.03.2005

(51) International Patent Classification (IPC):  E21B 17/10(2006.01) E21B 21/00(2006.01) E21B 17/22(2006.01) (86) International application number: PCT/GB2005/001199 (87) International publication number: WO 2005/093204 (06.10.2005 Gazette 2005/40)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU MC NL PL PT RO SE SI SK TR (30) Priority: 26.03.2004 GB 0406782 23.11.2004 GB 0425663 (71) Applicant: Downhole Products PLC Portlethen, Aberdeen AB12 4YA (GB)	(72) Inventors: KIRK, Ian Alastair Milltimber, Aberdeen AB13 0JF (GB) BARRON, William Bieldside, Aberdeen AB15 9BL (GB) CLARK, Alistair Bertram Westhill, Aberdeen AB32 6XF (GB) (74) Representative: Allan, James Stewart  Murgitroyd & Company 165-169 Scotland Street Glasgow G5 8PL Glasgow G5 8PL (GB)