Receiver function decomposition of OBC data: theory

Abstract

SUMMARY This paper deals with theoretical aspects of wavefield decomposition of Ocean Bottom Cable (OBC) data in the τ –p domain, considering a horizontally layered medium. We present both the acoustic decomposition and elastic decomposition procedures in a simple and compatible way. Acoustic decomposition aims at estimating the primary upgoing P wavefield just above the ocean-bottom, whereas elastic decomposition aims at estimating the primary upgoingP and S wavefields just below the ocean-bottom. Specific issues due to the interference phenomena at the receiver level are considered. Our motivation is to introduce the two-step decomposition scheme called ‘receiver function’ (RF) decomposition that aims at determining the primary upgoing P and S wavefields (RFP and RFS, free of any water layer multiples). We show that elastic decomposition is a necessary step (acting as pre-conditioning) before applying the multiple removal step by predictive deconvolution. We show the applicability of our algorithm on a synthetic data example.