(19)

(11)

EP 2 452 041 A2

(12)

(88) Date of publication A3: 21.04.2011 (43) Date of publication: 16.05.2012 Bulletin 2012/20 (21) Application number: 10797766.2 (22) Date of filing: 07.07.2010

(51) International Patent Classification (IPC):  E21B 33/13(2006.01) E21B 43/26(2006.01) E21B 33/138(2006.01) (86) International application number: PCT/US2010/041176 (87) International publication number: WO 2011/005836 (13.01.2011 Gazette 2011/02)

(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 SE SI SK SM TR (30) Priority: 09.07.2009 US 224378 P (71) Applicant: M-I LLC Houston, TX 77072 (US)	(72) Inventors: DAKIN, Eugene Langdon, Alberta TOJ 1X3 (CA) FERNANDEZ, Jorge Houston TX 77040 (US) BELL, Reginald J. Sugar Land TX 77479 (US) (74) Representative: Rivière, Sophie et al Osha Liang 32 Avenue de l'Opéra 75002 Paris 75002 Paris (FR)