(19)

(11)

EP 2 425 091 A2

(12)

(88) Date of publication A3: 30.06.2011 (43) Date of publication: 07.03.2012 Bulletin 2012/10 (21) Application number: 10765824.7 (22) Date of filing: 27.04.2010

(51) International Patent Classification (IPC):  E21B 19/14(2006.01) (86) International application number: PCT/GB2010/000822 (87) International publication number: WO 2010/125331 (04.11.2010 Gazette 2010/44)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR (30) Priority: 27.04.2009 GB 0907199 (71) Applicant: Derrick Services (UK) Limited Great Yarmouth NR31 0NF (GB)	(72) Inventor: MILLAR, Robert Great Yarmouth NR31 0NF (GB) (74) Representative: Cooke, Tracey  Novagraaf Norwich 12 Meridian Way Meridian Business Park Norwich NR7 0TA Meridian Business Park Norwich NR7 0TA (GB)