Reserves and probabilities; Synergism or anachronism

Abstract

This paper summarizes the state of the art in classifying reserves of oil and gas with the emphasis on worldwide inconsistencies in terminology and problems in reconciling reserves calculated with deterministic methods and those calculated and classified with probabilistic methods. Hypothetical models are developed to investigate possible relationships between reserves calculated with the two methods. These models indicate that the relationship between the reserves calculated from deterministic and probabilistic methods depends on the nature of the statistical distribution of the input variables; chiefly, the skewness of those distributions.