A Brief Summary of Hessian Based Modelling in a Shared Earth Environment

SUMMARY Validating an earth model by simulating a migration image is an important step in a shared earth environment. However, the high computational cost of generating 3D synthetic data, followed by the process of migration, limits the number of scenarios that can be validated. To overcome this computational cost, a novel strategy is used where a migration image is simulated by filtering a model. A filter represents one local element of the Hessian, which is obtained by computing the image of a single unit-strength scatterer in a macro velocity model (the impulse response of the filter). One of the key properties of this approach is that the model that describes a target-zone is decoupled from the macro-velocity model that is used to compute a filter. Consequently, different models can be filtered with the same filter. In addition, migration images of, for example, a walk-away VSP dataset or the influence of seismic uncertainties can be simulated. Therefore, these filters enhance a shared earth modelling approach.