Paper submitted to EAGE Annual 2026
Summary
Accurate seismic imaging in geologically complex areas relies on the availability of high-resolution subsurface models. While velocity models play a central role in improving structural imaging, velocity alone is insufficient to fully account for amplitude distortions arising from absorption, acquisition footprint, and geological heterogeneity. These effects can significantly degrade amplitude fidelity and limit the reliability of quantitative interpretation, particularly in challenging overburden settings.
Full-waveform inversion (FWI) has become a key technology for building detailed velocity models and enhancing seismic images. Approaches such as FWI Derived Reflectivity (FDR) utilize directional derivatives to extract reflectivity information directly from the inverted velocity. Early implementations produced a single pseudo-reflectivity volume, which was subsequently extended to partial-angle imaging through multiple parallel inversions. However, these angle-dependent products typically rely on predefined angles in pre-migration space, introducing uncertainty due to inaccurate angle estimation and non-uniform illumination. Recent developments in inversion methodology now enable the estimation of multiple physical parameters, including velocity, attenuation (Q), and angular impedance. This multi-parameter framework provides a more physically consistent description of the subsurface and improves both structural imaging and amplitude preservation. The resulting parameter sets also form the basis for deriving additional attributes, such as relative density and Vp/Vs ratios, which are important for amplitude-versus-angle (AVA) analysis and reservoir characterization. In parallel with these advances, the underlying modelling engine has been enhanced through the implementation of an elastic wave-equation solver.
The dataset considered in this study was acquired in 2016 in the Norwegian Sea, in water depths of approximately 800–1500 m. The target area is located on the Nyk High, a structural feature with proven Upper Cretaceous hydrocarbon potential, including the Aasta Hansteen field. Imaging in this region is complicated by fault shadows, igneous intrusions, and remobilized ooze in the overburden, which can obscure seismic signals and mask direct hydrocarbon indicators. These challenges make the area well suited for evaluating advanced Multi-Parameter FWI (MP-FWI) approaches.