Elastic Versus Viscoelastic Full Waveform Inversion of Near-offset and Wide-angle Data in the Presence of Attenuation

Abstract

Full Waveform Inversion (FWI) has proven to be a powerful tool to quantify the Earth's subsurface. In geological settings, such as gas clouds, gas sand, where attenuation is important, the application of FWI is still very challenging. We have developed a viscoelastic FWI in the time domain. In this paper, we investigate the need to properly account for attenuation when inverting long offset seismic data by comparing the results of elastic FWI applied to viscoelastic data and fully viscoelastic FWI. We carried experiments for short and long offset geometry of acquisition. The effect of attenuation could be divided into two parts: during wave propagation and during reflection. We find the presence of attenuation has a significant effect on wide-angle reflection data, both for reflection and propagation, but it has little or no effect on near-offset reflection data, suggesting that the elastic approximation is only sufficient when inverting pre-critical reflections and the attenuation should be taken into account while inverting wide-angle reflection data.