As petroleum resources become increasingly mature in their development, there will be a growing interest in their locality, recoverability, and the potential for Undiscovered Resources. Single poster presentations cannot fully describe the petroleum geology of a basin, but they can show on maps the basin character including total sedimentary thickness, and major structural elements; on regional cross sections the elements of stratigraphy and structure that reflect trap styles; and on columnar sections the principal source rocks and reservoir rocks. Resource occurrence is shown here in terms of Cumulative Production, Annual Production, Identified Reserves, and estimated Undiscovered Resources; the latter from both a geologic perspective and, selectively, a statistical projection of petroleum discoveries per well drilled vs wells drilled over time. We expect this type of presentation to be dynamic in character in the sense that it will be modified as new data and understanding come to our attention. The planned publication format is CD-ROM permitting low cost update of the information.
The World Petroleum Congress offers the only systematic published presentation of world petroleum resources. In earlier years, assessments were presented by broad areas with only a few countries specifically identified. In recent Congresses, assessment values have been presented by countries and aggregated by continental grouping. For the most part, our assessed values of Undiscovered Resources have been accomplished by basin but we had no complete access to basin reserve data. In recent years, however, commercial reserves data from Petroconsultants has become much more complete, enabling us to show resource occurrence by basins.
The resource data and basin outlines, of course, to a degree, will always be tentative, but we had anticipated for this meeting the presentation of a new world basin map, supported by isopachs and cross sections which, in the final analysis, we were unable to complete in time. The presentation map utilized, at 1: 20000000 scale, was originally prepared by Tom Hendricks and Anny Coury of the U.S.GS in 1978 and has since been digitized and modified by our World Energy Resources Program. Herein, we identify more than 500 sedimentary basins in the world but only about one-half of the basins have any chance of significant petroleum resources.
The reported resource values include cumulative production, Identified Reserves, and Undiscovered Resources. Because production numbers commonly are reported at the country level, we have had to estimate values by basin. We did this by assuming a proportional relationship between reserves and production but adjusting appropriately where we knew circumstances required a large reserve to production ratio for fields that were