Fortran programs for calculating connectivity of three-dimensional numerical models and for ranking multiple realizations

Given a three-dimensional numerical geological model it is often useful to determine the geological modeling cells that are connected in three dimensions. These connected three-dimensional bodies are referred to as gee-objects; a program geo_obj is presented to calculate the gee-objects From three-dimensional lithofacies, porosity and permeability models. Relevant summary statistics such as the number of gee-objects, their sizes and their tortuosities are reported. The connected volumes may be used for ranking geostatistical realizations, e.g. establishing realizations with low, median, and high connectivity. A program rank_obj is presented for this purpose. It may also be useful to rank realizations according to the connectivity to one particular location (e.g. a well location) or between two locations (e.g. injector-producer pair); programs rank_loc and rank2loc are presented for these situations. The concept of three-dimensional connectivity and the topology of three-dimensional Cartesian grids are well understood; however, the programs presented here will be useful to anyone dealing with three-dimensional numerical geological models. (C) 1998 Elsevier Science Ltd. All rights reserved.