METHODOLOGY OF HYDROCARBON RESOURCE APPRAISAL IN RELATIONSHIP TO THE “PETROLEUM ZONE” CONCEPT AND PROBABILISTIC CALCULATION

Publisher Summary This chapter discusses the methodology of hydrocarbon resource appraisal in relationship to the petroleum zone concept and probabilistic calculation. The evaluations of hydrocarbon resources deal with three kinds of reserves that are defined by their probability of existence. For each kind of reserve, there are corresponding methods of evaluation. The first type of method concerns the evaluation of proved reserves, that is, the amount of hydrocarbons known in fields under or on the point of exploitation. Calculation of these reserves, based on numerous and accurate data, requires sophisticated methods which take the technology of recovery methods into account. The second type of method concerns the evaluation of possible reserves, that is, the quantity of hydrocarbons not yet discovered but that might exist as the geological environment is favorable. With this kind of method the geological aspects are fundamental because they rule the existence and the amount of these reserves. These methods are applied to areas more or less unknown and the appraisals of their potential are tainted with uncertainty. The third type of method concerns the evaluation of probable reserves that come in addition to proved reserves either in recognized but not yet exploited fields or in exploited fields that benefit from technological progress. Calculations in this method are determined according to which of the first two cases applies.