M. KING HUBBERT AND HIS CONTEMPORARIES IN PRE-1975 OIL AND GAS RESOURCE APPARISAL

M. King Hubbert is known to many as the developer of a methodology for estimating undiscovered oil and gas potential, but less well known is how his methodology evolved over the years and how it compares to those of his contemporaries. Also less known is that Hubbert made several estimates of U.S. oil production, as well as estimates for U.S. natural gas and world oil.

Many features normally associated with Hubbert’s estimates are not evident in some of his earlier papers. Unlike those in some of his later publications, Hubbert’s production curves were originally asymmetrical, drawn freehand, and even multicyclic. It is only later that the better known symmetric logistic curve became the standard Hubbert methodology. Some of Hubbert’s early estimates even extrapolated fossil-fuel use hundreds of years into the future.

Hubbert originally used estimates of ultimate volumes generated by others in the oil industry and produced production curves that implied what the future production volumes might be. Some of these early estimates of ultimate production were merely consensus results from polls of industry geologists. Hubbert developed several methods of statistical extrapolation that estimated ultimate production using more quantitative approaches.

Many of the resource appraisals published at this time included little detail in their explanation of methodology used. Hubbert was much more consistent in documenting his methodology, his sources of data, and his assumptions. Because of the better documentation of Hubbert and a few of his contemporaries, such as Lewis G. Weeks and A.D. Zapp, it is possible to compare their extrapolations to results of exploration since their estimates were made. Not all Hubbert’s estimates share the “success” of his U.S. oil predictions, but many of the estimates of Hubbert’s contemporaries similarly do not fare well in the light of later exploration and application of new technologies.