When closing the loop with reservoir simulations, size matters

Seismic history matching is used to find models that match both production and time-lapse seismic data. These models should then be more accurate for forecasting and field management purposes. Accurate prediction of seismic behaviour is necessary and this can be affected by the fine scale heterogeneities. In some cases the impact of fine scale properties cannot be seen in seismic due to resolution limits. On the other hand, coarse scale models may miss such effects and therefore the seismic prediction is less reliable. We must also compare seismic data properly such that equivalent data are considered. Usually acoustic impedance is predicted but the seismic signal contains information missing here. We discuss these effects and how they can affect history matching, reducing the confidence in final models.