Fluid Front History Matching Using 4D Seismic and Streamline Simulation

Abstract

Abstract History matching of flow models is typically performed by using production data to calibrate the models. This implies that deficiencies in the models cannot be revealed until the consequences are observed in the well network. The outcome can be highly undesirable, like early water-breakthrough in a production well. A new method is proposed that enables calibration of the flow-model early in the production cycle before the deficiencies can be observed in the wells, so that pro-active action can be taken. The basic idea behind this new method is to modify a given set of flow properties (e.g. porosity, permeability, cell volume…) along the streamlines so that the computed fluid fronts coincide with the observed fluid fronts derived from 4D seismic. The latter can be extracted from time-lapse seismic cubes with amplitude-based seismic attributes or 4D classification results. The matching of fluid fronts with this method needs very few iterative steps, contrary to traditional history-matching techniques. This feature allows to reduce significantly the number of flow simulations run during the process. The use of streamline simulators is of key importance in this step. First, the inverse problem is reduced to several easy-to-solve one-dimensional problems. Secondly, the result of the matching is an average calibration of the flow properties along the streamlines from the injector wells to the fluid fronts. Hence, more frequent time-lapse seismic measurements give improved resolution to the calibration of the flow properties. The method proposed speeds up significantly the calibration of reservoir models to observed fluid fronts and facilitates a more active use of 4D seismic in reservoir management. The method is then demonstrated on different case studies.