Stochastic Signal Processing > Stochastic Stack
  • Step 1: Spatial data analysis.
    Interpretation and modelling of the experimental variograms computed in the offset and time directions on pre stack gather data enables to assess the signal and noise content of the seismic measurements in terms of contributive (signal) and non contributive (noise) part to the stacking process.

  • Step 2: Kriging.
    The usual stack gives equal weights to each amplitude in the offset direction for a fixed time. Figure a displays the usual stacked section. Kriged stack optimizes the weighting factor given to each amplitude by minimizing the variance of estimation of resulting stacked amplitude. Figure c displays the kriged stack section.
    Figures b and d displays the variance of estimation associated to the usual stack and to the kriged stack as a spatial quality index S Q I, that is a confidence interval expressed as a percentage of the stacked amplitude. Kriging estimation variance is minimized when compared to the usual stack. More confidence may be given to the kriged stack amplitude section.