(19)

(11)

EP 0 629 260 A1

(12)

(43) Date of publication: 21.12.1994 Bulletin 1994/51 (21) Application number: 93918760.0 (22) Date of filing: 02.02.1993

(51) International Patent Classification (IPC):  E21B 19/ 16( . ) (86) International application number: PCT/EP1993/000224 (87) International publication number: WO 1993/018276 (16.09.1993 Gazette 1993/22)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 11.03.1992 GB 19920005211 (71) Applicant: WEATHERFORD/LAMB, INC. (a Delaware Corporation) Houston, Texas 77056 (US)	(72) Inventor: PIETRAS, Bernd-Georg D-3002 Wedemark 2 (DE) (74) Representative: Lucas, Brian Ronald, et al  Lucas & Co. 135 Westhall Road Warlingham Surrey CR6 9HJ Warlingham Surrey CR6 9HJ (GB)