Quantitative Interpretation of Shallow Sediments through Seismic Elastic Inversion

This work presents the first application of AVO in a Bayesian elastic inversion approach applied to highresolution PSTM 2D marine seismic data for shallow water. The seismic data were inverted providing two outputs: inverted acoustic impedance (AI-inv) and inverted shear impedance (SI-inv). These attributes are sensitive to vertical and lateral variations in lithology, porosity and pore-fluid content in sedimentary rocks or layers, thereby allowing for an interpretation of the seismic section in geological terms. Traditionally, in shallow water, seismic data have mainly been used for seismostratigraphic purposes, i.e. qualitative investigations of geological subsurface structures. In this work, we extend the inversion process to an elastic approach, which besides acoustic impedance (AI) also provides shear related attributes like (shear impedance) SI or shear modulus. We use multi-offset data, which generate higher reflection angles, thereby allowing for an AVO elastic inversion. Additionally, a seismic processing workflow considering the true-amplitude processing was designed in order to precondition the recorded seismic.