U.S. Geological Survey Open-File Report 03-039
Figure 6

Figure 6.  Summary of technically recoverable oil grouped by accumulation size class estimated to occur in the Brookian Topset Play in NPRA.  Both histograms are based on the mean estimate of technically recoverable oil in the play.  (A) Number of accumulations grouped by oil accumulation size class.  (B) Volume of oil in each accumulation size class.  The left “tail” of each histogram is controlled by the assessment methodology, which is limited to accumulations larger than 50 million barrels of in-place oil or 250 billion cubic feet of technically recoverable natural gas.