(19)

(11)

EP 2 585 683 A2

(12)

(88) Date of publication A3: 01.03.2012 (43) Date of publication: 01.05.2013 Bulletin 2013/18 (21) Application number: 11798930.1 (22) Date of filing: 23.06.2011

(51) International Patent Classification (IPC):  E21B 47/00(2012.01) E21B 47/12(2012.01) E21B 47/06(2012.01) E21B 43/02(2006.01) (86) International application number: PCT/US2011/041653 (87) International publication number: WO 2011/163491 (29.12.2011 Gazette 2011/52)

(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: 24.06.2010 US 358331 P (71) Applicant: Chevron U.S.A. Inc. San Ramon, CA 94583 (US)	(72) Inventor: CAPDEROU, Christian San Ramon California 94583-0806 (US) (74) Representative: Nash, David Allan  Haseltine Lake LLP Redcliff Quay 120 Redcliff Street Bristol BS1 6HU Bristol BS1 6HU (GB)