The prospects for nuclear explosion stimulation of gas production in a portion of the Piceance Basin of Colorado have been evaluated for Equity Oil Company. Data from 38 wells were analyzed to determine: 1 . The optimum areas. 2 . The amount of gas in place amenable to production stimulation in these areas. 3. The most desirable stratigraphic section. 4. The average reservoir rock and fluid properties . The generally favorable areas containing more than 40 billion standard cubic feet (BSCF) per section were delineated. These two areas comprise approximately 69 sections in the northern portion of the study area and approximately 25 sections in the southern portion. Total gas in place in the most desirable stratigraphic section of these two areas is estimated to be 4. 5 trillion cu ft, based upon log and core analyses using a S% porosity and 70% water saturation cutoff. Maximum gas in place was calculated to be 100 BSCF per section. The Ft. Union Formation and upper portion of the Mesaverde Formation, Mesaverde I, with a combined thickness of about 2,000 ft were found to provide the most desirable stratigraphic section. These intervals consist of alternating layers of shale and sandstone with a typical sandstone/ shale ratio of approximately O. 30. Depths to the section's midpoint vary between 4, 700 and 7, 600 ft in the study area. The median porosity and water saturation of the Ft. Union as calculated from logs were 13. S% and 60%, respectively. Medians for the underlying Mesaverde were found to be 10.5% and 60%. Permeabilities of 0.02 and 0.1 rnillidarcy (md) were calculated for the Mesaverde I and the Ft. Union, respectively, by use of an empirical equation and assuming the calculated median water saturation to be the irreducible water saturation at the calculated median porosity. Since permeability to gas is a critical factor in determining the nuclear stimulation potential, it is recommended that at least two wells be reentered and tested to establish valid in- situ gas permeabilities. These e tests should also be used to qualitatively evaluate reservoir continuity in light of the apparently discontinuous nature of individual sandstone lenses.