The Natural Gas Studies Group (NGSG) of the Energy Resources Program of the U.S. Geological Survey conducts geologic research dealing with the origin, occurrence, and assessment of natural gas resources. Activities include collecting, synthesizing, and interpreting data to predict the distribution, quantity, quality, and availability of natural gas resources. The results of NGSG framework and process studies are integrated with newly-developed assessment methods to estimate the undiscovered resources of natural gas plays and the reserve-growth potential of known fields. Research is conducted on a topical and geographic basis and is subdivided into five current projects: (1) Continuous-Type Gas Accumulations, (2) Discrete Versus Continuous-Type Gas Accumulations, (3) Gas Hydrate Accumulations, (4) Coalbed Gas Accumulations, and (5) Rocky Mountain Basins Gas Projects.