(19)

(11)

EP 2 721 244 A2

(12)

(88) Date of publication A3: 18.04.2013 (43) Date of publication: 23.04.2014 Bulletin 2014/17 (21) Application number: 12719043.7 (22) Date of filing: 08.05.2012

(51) International Patent Classification (IPC):  E21B 17/01(2006.01) (86) International application number: PCT/GB2012/050942 (87) International publication number: WO 2012/172305 (20.12.2012 Gazette 2012/51)

(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: 16.06.2011 US 201161497885 P (71) Applicant: Wellstream International Limited Tyne and Wear NE6 3PF (GB)	(72) Inventors: TAN, Zhimin Houston, Texas 77041 (US) ZHANG, Yanqiu Houston, Texas 77041 (US) DONG, Qian Houston, Texas 77041 (US) HOU, Yucheng Houston, Texas 77041 (US) (74) Representative: Uno, Jennifer Elizabeth Hayes  Harrison Goddard Foote LLP Saviour House 9 St Saviourgate York, YO1 8NQ York, YO1 8NQ (GB)