Robust unidimensional PZ Summation

Abstract

PZ summation is a mandatory step in ocean bottom sensor multi-component PP seismic processing flow, to attenuate receiver ghost and peg leg multiples from upgoing wavefield. It consists of an adaptive sum between the hydrophone and geophone components to adapt the vertical component to pressure in a least square sense. However, in spurious situations (nongaussian noised conditions), a robust method IRLS (Interactive Re-weighted Least Square) may be a better choice to run linear convolutional adapting filter. That proposal was applied on receiver gathers of the OBC data from Jubarte area, Brazil, using near receiver stack sections to quality control. Similar quality was obtained when short adaptive windows were used, but better quality was attained when applied on a selected near receiver stack section, as compared to Wiener-Levinson PZ summation results. The proposed method became a robust option to run PZ summation and perform the unidimensional upgoing and downgoing field decomposition, processing the first order receiver ghost and peg leg multiples.