To most efficiently estimate oil and gas reserves for the State of Colorado, a county-by-county analysis was undertaken. This report is the eleventh 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.
Elbert County, located approximately 25 miles southeast of Denver, is within the south-central portion of the Denver Basin. In this county, oil and/or gas are produced from, in descending order of age, Ft. Hays Limestone, D sand and J sand. There are 11 fields considered active producers as of December 31, 1983. Of these, 10 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 20 production decline curves plotted, one for each field-horizon. Decline rates were calculated where there were sufficient production histories. Estimated oil reserves for Elbert County totaled 909,386 barrels. Estimated gas reserves for Elbert County totaled 11,773,658 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.
35 pages. Digital PDF download. OF-84-13D