In the art of interpretation of geophysical well surveys, empirical correlations between pairs of physical properties of rocks are used. These correlations permit measurements made of one physical property in a well bore to be interpreted in terms of another physical property which is of more significance in evaluating the reservoir behavior of a rock. Often, these correlations are developed through a series of laboratory measurements because the properties which are needed in evaluating a reservoir cannot be measured directly with the rock in place. In the evaluation of oil and gas reservoirs, interpretations based on such an approach have reached a high degree of development