To most efficiently estimate oil and gas reserves for the State of Colorado, a county-by-county analysis was undertaken. This report is the twelfth 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. 51 pages. Digital PDF download. OF-84-14D
Mesa County, located on the central western edge of Colorado, is partially bordering the Piceance Basin. In this county, oil and/or gas are produced from, in descending order of age, the Rollins Sandstone, Cozette Sandstone, Corcoran Sandstone, Mesaverde Sandstone, Frontier Sandstone, Mancos Shale, Dakota Sandstone, Buckhorn Sandstone, Cedar Mountain Shale, Morrison Sandstone, Saltwash Sandstone, and Entrada Sandstone. There are 23 fields considered active producers as of December 31, 1983. Of these, one is classified as an oil field (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 36 production decline curves plotted, one for each field-horizon. Decline rates were calculated where there were sufficient production histories. Estimated oil reserves for Mesa County totaled 4,230 barrels, from Bar X-Dakota/Morrison/Saltwash Production. Estimated gas reserves for Mesa County totaled 46,360,284 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 2003. 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.