The following objectives were accomplished: defining the CO/sub 2/ requirements for candidate enhanced oil recovery (EOR) reservoirs; generating alternative concepts for collecting, transporting, storing and processing CO/sub 2/ from naturally occurring sources and comparing them on the basis of cost effectiveness; and re-estimating the magnitude of the CO/sub 2/ EDR reserves based on the findings of this study. Fifty different natural gas purification processes for separating CO/sub 2/ were studied, and various modes of transportations and combinations were studied. If natural gases containing less than 10 mole percent CO/sub 2/ are processed, and trucks/trailers at 1000 psi and 90/sup 0/F are used to transport it (a distance of 100 miles), the CO/sub 2/ can be made available at the point of consumption for about $1.5/MSCF. The above cost includes all of the purification cost for 100 MMSCFD of natural gas containing 7.5 mole % CO/sub 2/. Considering only the natural gases from the Western Overthrust Belt and the Tuscaloosa Trend, the CO/sub 2/ reserves could be increased about 14 trillion standard cubic feet. It is recommended that DOE include the following in their future programs: Experimental work determining vapor-liquid equilibrium ratios for mixtures of methane-carbon dioxide at temperatures and pressures encountered in processing the natural gas. Experimental work determining other physical properties, such as heat capacity, conductivity, compessibility, viscosity, etc. for CH/sub 4/ to CO/sub 2/ mixtures containing other impurities, such as H/sub 2/S or others which exist in natural gases in the United States. High pressure truck/trailers should be studied in greater detail to determine an optimum pressure considering practical construction materials plus transportation rules and regulations.