Drill-bit seismic interferometry with and without pilot signals

We use different interferometry approaches to process the seismic signals generated by a drill-bit source in one well and recorded by seismic receivers located both in a second borehole and at the surface near the source well. We compare the standard interferometry results, obtained by using the raw drill-bit data without a pilot signal, with the new interferometry results obtained by using the drill-bit seismograms correlated with a reference pilot signal. The analysis of the stationary phase shows that the final results have different S/N levels and are affected by the coherent noise in the form of rig arrivals. The interferometry methods are compared by using different deconvolution approaches. The analysis shows that the results agree with the conventional drill-bit seismograms and that using the reference pilot signal improves the quality of the drill-bit wavefields redatumed by the interferometry method.