(19)

(11)

EP 2 265 796 A2

(12)

(88) Date of publication A3: 04.11.2010 (43) Date of publication: 29.12.2010 Bulletin 2010/52 (21) Application number: 09732831.4 (22) Date of filing: 17.04.2009

(51) International Patent Classification (IPC):  E21B 43/20(2006.01) E21B 43/30(2006.01) E21B 43/24(2006.01) (86) International application number: PCT/US2009/040922 (87) International publication number: WO 2009/129442 (22.10.2009 Gazette 2009/43)

(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 TR Designated Extension States: AL BA RS (30) Priority: 18.04.2008 US 46136 (71) Applicant: Shell Internationale Research Maatschappij B.V. 2596 HR The Hague (NL)

(72) Inventors: MILAM, Stanley, Nemec Houston TX 77055 (US) WELLINGTON, Scott, Lee Bellaire TX 77401 (US) JOSHI, Mahendra, Ladharam Katy TX 77450 (US) CUI, Jingyu Katy TX 77450 (US) REYNOLDS, Michael, Anthony Katy TX 77450 (US) (74) Representative: Matthezing, Robert Maarten et al Shell International Reseach Maatschappij B.V. Intellectual Property Services P.O. Box 384 2501 CJ The Hague 2501 CJ The Hague (NL)