(19)

(11)

EP 0 087 418 A1

(12)

(43) Date of publication: 07.09.1983 Bulletin 1983/36 (21) Application number: 81902875.0 (22) Date of filing: 02.10.1981

(51) International Patent Classification (IPC):  E21B 21/ 10( . ) E21B 47/ 18( . ) (86) International application number: PCT/US1981/001328 (87) International publication number: WO 1983/001087 (31.03.1983 Gazette 1983/08)

(84) Designated Contracting States: DE FR NL (30) Priority: 15.09.1981 US 19810302446 (71) Applicant: EXPLORATION LOGGING, INC. Sacramento, CA 95815 (US)	(72) Inventor: MUMBY, Edward Sheldon Carmichael, CA 95608 (US) (74) Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser Anwaltssozietät  Maximilianstrasse 58 D-80538 München D-80538 München (DE)