(19)

(11)

EP 0 026 188 A1

(12)

(43) Date of publication: 08.04.1981 Bulletin 1981/14 (21) Application number: 80900586.0 (22) Date of filing: 13.03.1980

(51) International Patent Classification (IPC):  E21B 21/ 10( . ) E21B 47/ 18( . ) E21B 34/ 06( . ) (86) International application number: PCT/US1980/000257 (87) International publication number: WO 1980/002051 (02.10.1980 Gazette 1980/22)

(84) Designated Contracting States: AT CH DE FR GB LU NL SE (30) Priority: 19.03.1979 US 19790021348 (71) Applicant: EXPLORATION LOGGING, INC. Sacramento, CA 95815 (US)	(72) Inventor: MUMBY, Edward Sheldon Sacramento, CA 95821 (US)