A comparison of radiated energy from diamond-impregnated coring and reverse-circulation percussion drilling methods in hard-rock environments

We compared and analyzed hard-rock drilling elastic energy emission between diamond-impregnated coring and reverse- circulation (RC) percussion drilling methods from an experiment at Brukunga, South Australia. The two drilling mechanisms generated very different seismic wavefields. This comparison emphasized their energy radiation differences and signal characteristics. From the field data, by investigating the raw data energy, frequency analysis, and crosscorrelation tests, the seismic records from percussive RC drilling provided a strong indication that the drill-bit energy could be suitable for drill-bit seismic imaging purposes; the energy radiation from the percussive RC bit could also provide high-resolution images with borehole seismic acquisition. In contrast, at comparable drilling conditions the coring drilling using a diamond-impregnated coring bit was quiet, the radiated acoustic energy from this drilling mechanism was difficult to detect by a surface receiver array, and there was no convincing visible drill-bit signal observed in the experiment