(19)

(11)

EP 0 159 314 A1

(12)

(43) Date of publication: 30.10.1985 Bulletin 1985/44 (21) Application number: 83903340.0 (22) Date of filing: 26.09.1983

(51) International Patent Classification (IPC):  E21B 47/ 18( . ) H03H 21/ 00( . ) G01V 1/ 36( . ) (86) International application number: PCT/US1983/001494 (87) International publication number: WO 1985/001586 (11.04.1985 Gazette 1985/09)

(84) Designated Contracting States: DE FR GB (71) Applicant: EXPLORATION LOGGING, INC. Sacramento, CA 95815 (US)	(72) Inventor: UMEDA, T. Berkeley, CA 94709 (US) (74) Representative: Patentanwälte Grünecker, Kinkeldey, Stockmair & Partner  Maximilianstrasse 58 D-80538 München D-80538 München (DE)