Zonation through seismic cluster analysis

Flow simulators require the specification of permeability and porosity at every node within the computational mesh. The original values of permeability and porosity need to be adjusted in a "calibration" or "history matching" step. In order to use optimization procedures, the dimensionality of the flow parameter system must be reduced to a manageable level. Grouping nodes or elements into associations with a single decision variable is called zonation. Seismic attributes depend in a complex way on the rock physics properties of the area of interest. The primary assumption of the seismic zonation method is that spatially continuous areas of similar seismic response have homogeneous fluid flow characteristics, and they can be used as parameter zones in flow models. A cluster analysis procedure is used to group attributes of similar seismic character into categories. Spatially connected elements with the same cluster category are assigned to the same seismic zone. The procedure has been used to reduce a 15,000 element grid to approximately 500 seismic zones. The procedure can also be used to upscale the seismic grid categories to a computational grid.