Multi-parameter Full Waveform Inversion Fundamentals

This technical report discusses multi-parameter Full Waveform Inversion (MP-FWI) and its applications within the seismic industry. It revisits the motivations behind MP-FWI and presents examples that demonstrate its advantages over traditional Full Waveform Inversion (FWI). The report outlines key components necessary for accurate parameter decoupling during simultaneous inversion. It explains how MP-FWI employs multiple models to interpret observed data and emphasizes the importance of long-wavelength kinematic effects for structural imaging while addressing dynamic effects through least-squares reverse-time migration. The methodology section details the reformulation of the variable-density acoustic wave equation and the use of the Inverse Scattering Imaging Condition to facilitate simultaneous inversion without requiring a speculative density model. The report also includes an example from the Central Graben in the North Sea, illustrating the effectiveness of MP-FWI in resolving structural anomalies. The conclusions highlight the core components of the implementation and the benefits of avoiding density model assumptions.