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(11)

EP 2 691 797 A1

(12)

(43) Date of publication: 05.02.2014 Bulletin 2014/06 (21) Application number: 11859018.1 (22) Date of filing: 31.03.2011

(51) International Patent Classification (IPC):  G01V 3/00(2006.01) (86) International application number: PCT/US2011/030639 (87) International publication number: WO 2012/134468 (04.10.2012 Gazette 2012/40)

(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 (71) Applicant: Halliburton Energy Services, Inc. Houston, TX 77072 (US)	(72) Inventor: RODNEY, Paul F. Spring, Texas 77389 (US) (74) Representative: Patel, Nikesh et al A.A. Thornton & Co. 235 High Holborn London WC1V 7LE London WC1V 7LE (GB)