Preprocessing of SWD data

Chapter 8 (Preprocessing of SWD data) – describes preprocessing of the seismic-while-drilling data, i.e., the production of interpretable seismograms. Preprocessing includes correlation, stacking, time correction, phase correction and deconvolution. Modeling of drill-string waves is used to interpret the delays of the pilot signals in the correlations. In this chapter, significant extensions have been made in the computation of the propagation matrix for downhole signal and noise in the drill string, analysis of drill-string multiples in downhole pilot data, downhole pilot-delay synchronization and, last but not least, the estimation of the drill-bit SWD signature by the downhole ground force. An overview of new SWD results obtained with downhole pilot signal is given.