(19)

(11)

EP 0 960 262 A1

(12)

(43) Date of publication: 01.12.1999 Bulletin 1999/48 (21) Application number: 98901587.0 (22) Date of filing: 13.01.1998

(51) International Patent Classification (IPC):  E21B 23/ 01( . ) E21B 33/ 129( . ) E21B 33/ 12( . ) (86) International application number: PCT/NO1998/000009 (87) International publication number: WO 1998/035130 (13.08.1998 Gazette 1998/32)

(84) Designated Contracting States: DK FR GB NL (30) Priority: 06.02.1997 NO 19970000561 (71) Applicants: Brönnteknologiutvikling A/S 7002 Trondheim (NO) Maritime Well Service A/S 4033 Forus (NO)	(72) Inventors: ANDERSEN, Frode N-7021 Trondheim (NO) PEDERSEN, Dag, Ravn N-7021 Trondheim (NO) (74) Representative: Avellan-Hultman, Olle, et al  Axel Ehrners Patentbyra AB, inc. Avellán-Hultmann Patentbyra AB P.O.Box 10316 100 55 Stockholm 100 55 Stockholm (SE)