(19)

(11)

EP 2 507 468 A2

(12)

(88) Date of publication A3: 13.10.2011 (43) Date of publication: 10.10.2012 Bulletin 2012/41 (21) Application number: 10784556.2 (22) Date of filing: 02.12.2010

(51) International Patent Classification (IPC):  E21B 33/038(2006.01) E21B 17/01(2006.01) (86) International application number: PCT/EP2010/068771 (87) International publication number: WO 2011/067353 (09.06.2011 Gazette 2011/23)

(84) Designated Contracting States: AL 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 RS SE SI SK SM TR (30) Priority: 02.12.2009 US 265805 P (71) Applicant: Stena Drilling Ltd. East Tullos Aberdeenshire AB12 3BG (GB)	(72) Inventor: HUMPHREYS, Gavin Aberdeen AB12 3BG (GB) (74) Representative: Lucas, Brian Ronald  Lucas & Co. 135 Westhall Road Warlingham, Surrey CR6 9HJ Warlingham, Surrey CR6 9HJ (GB)