(19)

(11)

EP 1 771 639 A2

(12)

(88) Date of publication A3: 20.04.2006 (43) Date of publication: 11.04.2007 Bulletin 2007/15 (21) Application number: 05759690.0 (22) Date of filing: 24.06.2005

(51) International Patent Classification (IPC):  E21B 34/10(2006.01) (86) International application number: PCT/GB2005/002506 (87) International publication number: WO 2006/000799 (05.01.2006 Gazette 2006/01)

(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: 24.06.2004 GB 0414128 (71) Applicant: Renovus Limited Aberdeen AB33 8YH (GB)	(72) Inventor: PIA, Giancarlo Tomasso Pietro Aberdeen AB22 8YH (GB) (74) Representative: Shanks, Andrew et al Marks & Clerk 19 Royal Exchange Square GB-Glasgow G1 3AE GB-Glasgow G1 3AE (GB)