(19)

(11)

EP 2 449 209 A2

(12)

(88) Date of publication A3: 31.03.2011 (43) Date of publication: 09.05.2012 Bulletin 2012/19 (21) Application number: 10800287.4 (22) Date of filing: 29.06.2010

(51) International Patent Classification (IPC):  E21B 43/00(2006.01) E21B 34/06(2006.01) E21B 43/12(2006.01) (86) International application number: PCT/US2010/040311 (87) International publication number: WO 2011/008522 (20.01.2011 Gazette 2011/03)

(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 SE SI SK SM TR (30) Priority: 29.06.2009 US 221169 P (71) Applicants: Shell Oil Company Houston, TX 77252-2463 (US) SM  Shell Internationale Research Maatschappij B.V. 2596 HR The Hague (NL)	(72) Inventor: BREWER, James, Robert Gaylord Michigan 49735 (US) (74) Representative: Matthezing, Robert Maarten et al Shell International B.V. Intellectual Property Services P.O. Box 384 2501 CJ The Hague 2501 CJ The Hague (NL)