Joint Assimilation of Production Data and Time-Lapse Density Changes from Seismics Using the Representer Method

We used the representer method to perform data assimilation (automatic history matching) of production data and 4D seismic data to estimate the permeability field in numerical reservoir models. The 4D seismic data were incorporated in the form of interpreted time-lapse density changes. The representer method requires two numerical simulations per measurement which becomes infeasible if seismic data in all grid blocks would be taken into account. Therefore, only the most informative data at the saturation front moving over time were used in the assimilation. The method was tested in a twin-experiment using synthetic data. The results were assessed in terms of the quality of the history match (mismatch between ‘true’ and simulated measurements) and in terms of predictions (mismatch between ‘true’ and simulated predictions after the history matching period). We found a clear improvement of the joint assimilation inversion over individual assimilation of production and seismic data.