Abstract: Statistical History of Petroleum Exploration in Denver Basin

L. J. Drew, J. H. Schuenemeyer, D. H. Root

Once a stratigraphic unit is found to be oil-bearing, exploratory drilling concentrates on the search for individual fields in the formation. A method for forecasting the future course of a partly completed play has been tested on the Denver basin. Calculations were based on extensive data consisting of dates and locations of 22, 577 wells drilled between January 1, 1949, and December 31, 1974, and the discovery dates, reserves estimates, cumulative production, and production acreage of 909 fields.

Well locations were used to calculate the effective basin area--that part of the basin where exploration geologists are willing to site wells--and to calculate how much of that area has been explored as drilling proceeds.

The past discovery record was examined to determined the efficiency of actual exploration relative to that of random drilling. For large targets, actual exploration was found to be much more efficient than random drilling; for very small targets, the two methods were about equally efficient.

Exploration efficiency is combined with the discovery record and the effective basin size to forecast the ultimate amount of oil to be found, the sizes of fields in which it will be found, and the rate at which it will be found.

AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC