(19)

(11)

EP 2 007 970 A2

(12)

(88) Date of publication A3: 06.12.2007 (43) Date of publication: 31.12.2008 Bulletin 2009/01 (21) Application number: 07760926.1 (22) Date of filing: 19.04.2007

(51) International Patent Classification (IPC):  E21B 43/00(2006.01) E21B 43/11(2006.01) (86) International application number: PCT/US2007/066983 (87) International publication number: WO 2007/124368 (01.11.2007 Gazette 2007/44)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR Designated Extension States: AL BA HR MK RS (30) Priority: 19.04.2006 US 793031 P 18.04.2007 US 737058 (71) Applicant: M-I LLC Houston, TX 77072 (US)	(72) Inventors: JONES, Doug Houston, TX 77077 (US) RAY, Randy Houston, TX 77005 (US) FORRESTER, Jay Bellaire, TX 77401 (US) (74) Representative: Brochard, Pascale et al Osha Liang 32 avenue de l'Opéra 75002 Paris 75002 Paris (FR)