3D and 4D Petrophysical Seismic Inversion

The petrophysical seismic inversion is a method driven by petro-elastic models. It updates a fine-scale geological model in Depth to make it fully compatible with pre-stack seismic measurements and is a patented technique initially developed in collaboration between Marathon Oil and CGGVeritas.

The extension to 4D, developed in collaboration with StatoilHydro is a natural extension as saturations and pressure are explicitly handled in the petro-elastic models and can be optimized with time-lapse seismic measurements, under control from production data.

The lecture touches on petro-elastic models and seismic elastic forward modeling, and proceeds to pre-stack and time-lapse seismic inversion, including the interaction of seismic processing and reservoir model building.
Integration of geological, geophysical and production information requires Geomodels compatible with flow simulators as well as geological modeling, seismic interpretation and inversion; the elusive “Shared Earth Model” with its associated issues:

Scale: small-scale features, potentially below seismic resolution to represent heterogeneities critical for flow simulation and for the validity of the petro-elastic model.
Different domains: Two-way travel times and Depth.
Multi-axes handling for time-lapse: Depth if compaction occurs and different TWTime per vintage.