Methodology for the 2005 USGS Assessment of Undiscovered Oil and Gas Resources, Central North Slope, Alaska

Undiscovered oil and gas resources in each of 24 plays (assessment units) within the Alaska Central North Slope were estimated using a deposit simulation analysis in the assessment by the U.S. Geological Survey in 2005. Plays were identified by assessor geologists who specified geologic attributes, risks, and number of prospects for each play. From this information, sizes of oil and gas accumulations were simulated using a Monte Carlo algorithm. The number of such accumulations considered in a given simulation run was obtained from the distribution of the number of prospects. Each prospect in each successful simulation run was risked. This process yielded size-frequency distributions and summary statistics for the various petroleum categories. Estimates of resources from individual plays were then aggregated, and measures of uncertainty computed.