The purpose of this report is to provide geologic data and interpretations in these Rocky Mountain basins that will ultimately lead to an improved understanding of the nature and distribution of tight gas-bearing reservoirs and aid recovery technology. The report is in two parts; the first is a discussion of the geologic characterization of low-permeability gas reservoirs in selected wells from the Greater Green River Basin; the second is a summary report of investigations conducted during FY-1984 in the Piceance Creek Basin, including the MWX site. Both parts have been processed separately for inclusion in the Energy Data Base.