(19)

(11)

EP 2 231 994 A2

(12)

(88) Date of publication A3: 03.09.2009 (43) Date of publication: 29.09.2010 Bulletin 2010/39 (21) Application number: 08866510.4 (22) Date of filing: 22.12.2008

(51) International Patent Classification (IPC):  E21B 10/08(2006.01) E21B 10/16(2006.01) E21B 10/52(2006.01) (86) International application number: PCT/US2008/088014 (87) International publication number: WO 2009/086302 (09.07.2009 Gazette 2009/28)

(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: 21.12.2007 US 16243 (71) Applicant: Baker Hughes Incorporated Houston, TX 77027 (US)	(72) Inventors: PESSIER, Rolf Carl The Woodlands TX 77380 (US) FELDERHOFF, Floyd The Woodlands TX 77380 (US) BUSKE, Robert J. The Woodlands TX 77380 (US) (74) Representative: Hano, Christian et al v. Füner Ebbinghaus Finck Hano Patentanwälte Mariahilfplatz 3 81541 München 81541 München (DE)