Geophysical and geostatistical reservoir characterisation of ckalk fields and its use in reservoir simulation

The work flow in the project has been first to invert the seismic data for relative impedance, then do the interpretation, build low-frequency model and do the final inversion for acoustic impedance and porosity. An inline has also been processed for AVO attributes and an AVO inversion for Poisson's ratio has been performed. Then the 3D data is depth converted, the impedance is corrected for fluid content before geostatistical characterisation of porosity and permeability is performed. Water saturation is modelled and hydrocarbon pore volume is calculated. Furthermore, the importance of fracturing the present field is assessed. On the geostatistical characterisations ranking is performed. This is a new ranking technique developed in this project. The ranking is selecting between the hundred stochastic realisations a low producing and a high producing model. Reservoir simulation is performed on these two models, as well as on a reference model, built at the beginning of the project before the stochastic models were available. The results of this modelling are compared. The project has demonstrated the use an integrated reservoir characterisation technique on data from the Roar field. It has been demonstrated how seismic data can be used through inversion in qualitatively prediction of porosity. The use of geostatistical methods is demonstrated and 100 equally probable reservoir models are generated. In the project a technique for ranking the reservoir models is developed an demosntrated. In this way it becomes easy to quantify the variablility in form of variability in oil production. The project has successfully shown how different disiplines can be combined and utilised in the reservoir description