History Matching of Production Data and 4D Seismic Data on Girassol Field

In order to match simultaneously the production data and time-lapse seismic data, two methodologies are explained and applied on an existing reservoir flow model for the deep offshore Girassol field, Angola. The workflow for both is based on 3D and 4D seismic facies characterisation. The next step is to upscale in the reservoir flow model, the petrophysical properties coming from a petrophysical inversion of the 3D seismic impedances. This reservoir flow model provides pressure and saturation for computing some simulated impedances to be compared to the real ones. During the update of the reservoir model, non-reservoir cells that proved to have shown production induced impedance changes are reassigned to reservoir facies. For the first method, only a few cells are concerned preserving active cells of the initial model. For the second one to improve the match of 4D seismic data, a selected area is completely updated using uncertainty on seismic facies. In a history matching optimisation loop, the breakthrough time of an injector/producer pair is significantly improved for both methods when compared to the initial reservoir model. These methods highlight the added-value of the 4D in the history matching phase.