Document Type and Number:
Japanese Patent JP2806922
Kind Code:
B1
Application Number:
JP30004697A
Publication Date:
September 30, 1998
Filing Date:
October 31, 1997
Export Citation:
International Classes:
E21B3/02; E02D7/16; E02D7/22; E02D13/00; E21B7/20; (IPC1-7): E02D7/16; E02D7/22