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(11)

EP 2 173 961 A2

(12)

(43) Date of publication: 14.04.2010 Bulletin 2010/15 (21) Application number: 08772346.6 (22) Date of filing: 02.07.2008

(51) International Patent Classification (IPC):  E21B 10/567(2006.01) E21B 10/42(2006.01) (86) International application number: PCT/US2008/068985 (87) International publication number: WO 2009/006510 (08.01.2009 Gazette 2009/02)

(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 MT NL NO PL PT RO SE SI SK TR Designated Extension States: AL BA MK RS (30) Priority: 02.07.2007 US 947591 P (71) Applicant: Baker Hughes Incorporated Houston, TX 77027 (US)	(72) Inventor: SHERWOOD, William, H. Spring, TX 77388 (US) (74) Representative: Hano, Christian  v. Füner Ebbinghaus Finck Hano Patentanwälte Mariahilfplatz 3 81541 München 81541 München (DE)