(19)

(11)

EP 1 792 046 A1

(12)

(43) Date of publication: 06.06.2007 Bulletin 2007/23 (21) Application number: 05787182.4 (22) Date of filing: 12.09.2005

(51) International Patent Classification (IPC):  E21B 33/08(2006.01) (86) International application number: PCT/GB2005/003506 (87) International publication number: WO 2006/030186 (23.03.2006 Gazette 2006/12)

(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 LV MC NL PL PT RO SE SI SK TR (30) Priority: 14.09.2004 GB 0420381 28.02.2005 US 69493 (71) Applicant: Cromar Limited Aberdeen AB23 8EG (GB)	(72) Inventors: MCKAY, Frederick Duguid Aberdeen AB21 7FS (GB) BLACK, Colin Alexander Inverurie, Aberdeenshire AB51 4RY (GB) (74) Representative: Lincoln, Matthew  Kennedys Patent Agency Limited 185 St Vincent Street Glasgow G2 5QD Glasgow G2 5QD (GB)