Seismic characterization of waste disposals by full waveform inversion: possibilities and challenges

Geophysical characterisation of potential geological sites for nuclear waste disposal is important to develop a repository design adequate to ensure safety and waste isolation. Seismic full waveform inversion (FWI) aims at a complete seismic characterization by exploiting the full signal content of seismic measurements. The aim of FWI is to fit iteratively the relevant signals (amplitude and phase) by numerical solutions of the full wave equation. The main product of FWI are multi-parameter models of acoustic, elastic, viscoelastic, anisotropic material properties which can explain the traveltime and amplitudes of (selected) recorded signals. Such multi-parameter models can help to improve the petrophysical characterization of geological site properties in-situ. In combination with the complementary information from reflection seismic images, FWI can thus help to characterize and monitor the in-situ conditions of rocks and therefore contribute to the appraisal of disposals.In this paper we discus some aspects and ingredients of FWI relevant to assess possible future applications of FWI for site characterization. We hope to give some ideas and guidelines that help to decide whether the application of FWI can be beneficial and the efforts are worth it. ... mehrFor these purposes we first summarize some fundamental aspects of current FWI technology. Afterwards we illustrate the potential by showing applications to marine and land seismic data. Finally, we give a short outlook on possible future developments.