1. A method for determining effects of perforation on a rock formation, comprising: obtaining a sample of the rock formation; creating a perforation tunnel in the sample of the rock formation; at least one of subdividing the core sample into subsamples and making a three dimensional tomographic image of each subsample by utilizing x-ray computer tomographic imaging and making a three dimensional tomographic image of the sample of the rock formation and splitting the image thereof into sub images of selected subvolumes of the rock formation sample; and estimating at least one physical property of the rock formation from each tomographic image; and utilizing values of the said at least one physical property of each subsample along with subsample's distance from the tunnel axis as a function describing radial profiles of the effect of perforation on the rock formation.