Acquisition Design for Incoherent Shooting

In blended seismic data acquisition, the blended source wavefield should be designed in such a way that it has a large spatial bandwidth without notches. This corresponds to using blended source arrays with a high degree of incoherency. The three-dimensional (x,y,t) autocorrelation function of the blended source wavefield at the surface is proposed as a surface-related, quantitative measure of incoherency. In this assessment the subsurface is not involved. A second measure is proposed that does include the propagation effects of the near- and subsurface on the illumination by the blended source wavefield. For each subsurface gridpoint the autocorrelation function of the incident blended source wavefield - being represented by a dispersed time series - is judged for its whiteness. This result can be extended to angle-dependent illumination by computing the cross-correlation function as well.