To most efficiently estimate oil and gas reserves for the State of Colorado, a county-by-county analysis was undertaken. This report is the tenth in a series of oil and gas reserve investigations undertaken for those counties in which oil and/or gas was being produced at that time. 56 pages. Digital PDF download. OF-84-12D
Moffat County, located in the northwestern corner of Colorado, is partially with the Sand Wash Basin. In this county, oil and/or gas are produced from, in descending order of age, the Wasatch Sandstone, Ft. Union Sandstone, Lance Sandstone, Lewis Shale, Mesaverde Sandstone, Niobrara Limestone, Frontier Sandstone, Mancos Shale, Dakota Sandstone, Morrison Sandstone, Curtis Sandstone, Entrada Sandstone, Sundance Sandstone, Nugget Sandstone, Shinarump Conglomerate and Weber Sandstone. There are 28 fields considered active producers as of September 30, 1983. Of these, 11 are classified as oil fields (based on cumulative gas-oil ratio (GOR) of 15:1).
Production decline curves are plotted for each currently producing horizon within each field (field-horizon). There are 42 production decline curves plotted, one for each field-horizon. Decline rates were calculated where there were sufficient production histories. Estimated oil reserves for Moffat County totaled 6,258,073 barrels. Estimated gas reserves for Moffat County totaled 221,910,846 MCF. Note that the gas reserve calculations are based on a 20-year projection, therefore they do not account for gas production after the year 2002. These figures also do not account for production increases due to secondary and/or tertiary recovery not already in progress, or account for undiscovered reserves, nor do they reflect changes in economics and demand.