Extracting the Weak Signal of the Drill-Bit from Seismic While Drilling Data

As a new borehole seismic technique, seismic while drilling (SWD) uses the vibrations produced by the drill-bit while drilling as a down hole seismic energy source. The continuous signals generated by the drill bit are recorded by a pilot sensor attached to the top of the drill string and by receivers located at selected positions around the borehole. In real SWD data, both the weak drill-bit signal and the strong noise are typically continuous and superimposed at all times. So the key technique is how to extract the weak drill-bit signal from all kinds of strong noise. We proposed a new method to directly extract the drill-bit signal from the raw-field SWD data acquired at the surface. Applying this new method to a real SWD data shows our proposed method is an effective technique for drill-bit signal extraction, though it has shortcomings.