Abstract: An electronically stored model for a reservoir can include a plurality of hierarchical levels and a plurality of cells representing corresponding portions of the reservoir. The model can include a dimension and a cell number corresponding to the reservoir. A dimension of a cell of an nth hierarchical level can be defined in terms of a dimension of a cell of a first hierarchical level and an array of vertex coordinates along one or more axes can be generated. The model can include a ratio of dimensions among hierarchical levels for improved reservoir modeling. The model can include a ratio of permeability among hierarchical levels for improved reservoir modeling.