(19)
(11)
EP 0 408 667 A1
(12)
(43)
Date of publication:
23.01.1991
Bulletin 1991/04
(21)
Application number:
89905949.0
(22)
Date of filing:
21.04.1989
(51)
International Patent Classification (IPC):
G01V
1/
40
( . )
E21B
47/
16
( . )
(86)
International application number:
PCT/US1989/001641
(87)
International publication number:
WO 1989/010572
(
02.11.1989
Gazette 1989/26)
(84)
Designated Contracting States:
DE FR GB NL
(30)
Priority:
21.04.1988
US 19880184326
(60)
Divisional application:
93111079.5 / 0565141
(71)
Applicant:
SANDIA CORPORATION
Albuquerque, NM 87185-5800 (US)
(72)
Inventor:
DRUMHELLER, Douglas, Schaeffer
Cedar Crest, NM 87008 (US)
(74)
Representative:
Meyers, Ernest
Office de Brevets FREYLINGER & ASSOCIES B.P. 1 321, route d'Arlon
L-8001 Strassen
L-8001 Strassen (LU)
(54)
ACOUSTIC DATA TRANSMISSION THROUGH A DRILL STRING