OF-84-09 Estimated Oil and Gas Reserves for Cheyenne County, Colorado


To most efficiently estimate oil and gas reserves for the State of Colorado, a county-by-county analysis was undertaken. This report is the seventh 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. 35 pages. Digital PDF download. OF-84-09D

Cheyenne County, located in east central Colorado, is approximately 100 miles due east of Colorado Springs, straddling the Las Animas Arch. In this county, oil and/or gas are produced from, in descending order of age, the Topeka (Shawnee) Carbonate, Marmaton Limestone, Morrowan Sandstone and Mississippian-Spergen Limestone. There are 15 fields considered active producers as of September 30, 1983. Of these, 14 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 22 production decline curves plotted, one for each field-horizon. Decline rates were calculated where there were sufficient production histories. Estimated oil reserves for Cheyenne County totaled 11,742,162 barrels. Estimated gas reserves for Cheyenne County totaled 33,837 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.