PURPOSE: To surely attain the data transmission with high S/N by converting a signal to be transmitted to an ultrasonic wave, and propagating and transmitting it in a fluid in an underground cavity.
CONSTITUTION: In the internal cavity of a tip-most drill pipe 45 in which a transmitting part 90 and a storage container 8 where a measuring instrument 80 for logging is housed are loaded, an ultrasonic wave oscillating means 50 is provided. At a ground side, an ultrasonic wave receiving means 60 is provided at a mud supplying pipe 61 connected to the upper edge of the upper-most drill pipe 45. The cavity in many linked drill pipes 4, 4... is filled with the ultrasonic wave generated from the ultrasonic wave oscillating means 50, the wave is propagated in an upper-most drill pipe 45 direction, namely, to the ground side with the circulated mud as propagation media and received to the ultrasonic wave receiving means 60.
ISHIKAWA SHINSUKE
INOUE SATORU
MAEKAWA TAKAAKI
HISANAGA AKIRA
