The World Energy Resources Program of the U.S. Geological Survey applies an assessment technique to international petroleum provinces that was established initially for purposes of domestic analysis. Additions to the procedures that permit quasi quantitative evaluations of exploration maturity are being evolved for the assessment process, as are methods of disaggregating the assessment into a field size distribution. Program results to date indicate that while oil reserves are high, they are also declining steadily because of continued production in excess of discovery such that a deficit of ~70 billion bbl has accumulated in the 10-year period between 1971 and 1981. More disturbing than the discovery/production deficit, however, is the assessment that the distribution of world crude oil has been established, and no new areas with undiscovered resources of > 20 billion bbl of oil have a most likely probability of being discovered.