(19)

(11)

EP 2 021 835 A2

(12)

(88) Date of publication A3: 03.04.2008 (43) Date of publication: 11.02.2009 Bulletin 2009/07 (21) Application number: 07783066.9 (22) Date of filing: 02.05.2007

(51) International Patent Classification (IPC):  G01V 3/28(2006.01) (86) International application number: PCT/US2007/067977 (87) International publication number: WO 2007/131007 (15.11.2007 Gazette 2007/46)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR Designated Extension States: AL BA HR MK RS (30) Priority: 04.05.2006 US 797556 P (71) Applicant: Shell Internationale Research Maatschappij B.V. 2596 HR The Hague (NL)	(72) Inventors: HAGIWARA, Teruhiko Houston, TX 77025-4002 (US) BANNING-GEERTSMA, Erik Jan Houston, Texas 77035 (US) OSTERMEIER, Richard Martin Houston, TX 77005-1923 (US) (74) Representative: Zeestraten, Albertus W. J.  Shell International B.V. Intellectual Property Services P.O. Box 384 2501 CJ The Hague 2501 CJ The Hague (NL)