The DOE Office of Naval Petroleum and Oil Shale Reserves (NPOSR) was concerned that a significant gas loss from NOSR No. 3 to nearby producing commercial wells in the Rulison Field could occur through migration across the reserve boundary. The DOE also wanted an estimate of the expected production rate from several proposed offset wells. To answer these questions, the following elements were used in this study: hydraulic fracture treatment and completion records, geophysical logs, a geologic study (Knutson 1985), DOE field test data, approximately 4 years of production data from 39 industry wells in the adjacent Rulison Field, reservoir analysis computer codes, and reservoir engineering calculations. DOE's Morgantown Energy Technology Center (METC) conducted a reservoir simulation study and an engineering analysis on gas migration for two tight lenticular sandstone units, the Wasatch Formation and the lenticular portion of the Mesaverde Group, in Garfield County, Colorado. The study quantified potential gas loss through migration from the Naval Oil Shale Reserve (NOSR) No. 3 to nearby producing wells located in the Rulison Field. It also forecasted production for proposed NOSR No. 3 wells located at previously selected sites, offsetting commercial wells outside the reserve. This study also estimated the potential for gas migration from NOSR No. 3 to the Rulison Field for wells completed in the blanket-like Cozzette and Corcoran sandstones near the bottom of the Mesaverde Group. 27 refs., 29 figs., 17 tabs.