Distribution and Quantitative Assessment of World Crude-Oil Reserves and Resources

The enumeration of world crude-oil reserves and resources is a difficult undertaking. One must rely on data gathered by others and, through various spot-check and cross-check mechanisms, distinguish the reasonable from the unreasonable. Estimating techniques vary; standards of measurement vary; classification of the reported elements differ; and, in some cases, even the recognition of what is being reported is obfuscated by language and nomenclatural ambiguities. Therefore, to improve understanding of world petroleum resources, it is prudent to describe the methodologies and measurement standards explicitly, to disaggregate the data as much as possible to gain insight into the source of the differences, and to standardize the classification and nomenclature scheme to establish unambiguous communication.