The objectives of US Geological Survey work are to conduct geologic research characterizing tight gas-bearing sequences in the western United States. The USGS research during the last few years has been in the Greater Green River, Piceance Creek, and Uinta basins of Wyoming, Colorado, and Utah. Additional critical objectives are to provide geologic consulting and research support for ongoing Multiwell Experiment (MWX) engineering, petrophysical, log-analysis, and well-testing research. Within these basins our research efforts have been regional in scope. The Greater Green River basin has high priority because most of the Piceance basin studies have been completed or are being completed, and because the Greater Green River basin has the greatest areal extent and greatest known thicknesses (>10,000 ft) of strata containing dominantly gas-bearing sandstone reservoirs. The Uinta Basin may have greater thicknesses of tight-gas strata, but there are presently no wells that have been drilled through the Cretaceous Mesaverde Group in the deeper parts of the basin. The objectives of these focused investigations are to provide geologic models that can be compared and utilized in tight gas-bearing sequences elsewhere. 18 figs.