Continuous Full-Wave Sonic Logging In A Dry Hole

This paper describes a new concept of continuous full-wave sonic logging (FWS) in a dry hole. The<br>continuous FWS in a tube provides physical properties at narrow intervals under the dry condition. The<br>method uses a synthetic rubber tube that enables continuous FWS to be conducted in a dry hole, by<br>sealing the dry hole wall and preventing water leakage. The addition of water made the tube expand and<br>contact firmly to the hole wall. FWS collects sonic signals as waveforms through the tube, and<br>successively provides a larger quantity of higher resolution data than conventional downhole<br>measurement under the dry condition by receiving sonic signals more precisely and effectively.<br>Although the method could identify individual fractures in bedrock in all hazards, it cannot be used at a<br>low velocity part of less than 1.5 km/sec in water due to the structure of the tube.