(19)

(11)

EP 2 084 364 A2

(12)

(88) Date of publication A3: 28.08.2008 (43) Date of publication: 05.08.2009 Bulletin 2009/32 (21) Application number: 07864706.2 (22) Date of filing: 21.11.2007

(51) International Patent Classification (IPC):  E21B 21/14(2006.01) (86) International application number: PCT/US2007/085368 (87) International publication number: WO 2008/064301 (29.05.2008 Gazette 2008/22)

(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 (30) Priority: 21.11.2006 US 866699 P (71) Applicant: Prospector Drill & Tool Co. Alvin, TX 77512 (US)	(72) Inventor: STAMOULIS, Stefan Alvin, Texas 77512 (US) (74) Representative: Merrifield, Sarah Elizabeth  Boult Wade Tennant Verulam Gardens 70 Gray's Inn Road London WC1X 8BT London WC1X 8BT (GB)