Various enhanced oil recovery (EOR) methods were considered in an economic analysis of the twenty-six largest fields in Wyoming. This analysis indicates that a majority of the fields are currently best suited to polymer augmented waterflooding or CO2 flooding, based on an average price of $1.25/Mscf for CO2 and $2.50/lb for polymers. With these prices, all floods were economically viable in reservoirs less than 6000 feet deep at a base price of about $26.00/bbl for oil. In deeper reservoirs, most CO2 floods were uneconomic when using a twelve percent minimum acceptable rate of return as the basis of decision. A lower CO2 price, in the range of $0.50 – $0.75 per Mscf, would make most of the CO2 floods economic in reservoirs up to 12000 feet deep.

As a result of the anticipated increase in enhanced oil recover revenues to the state through royalties and taxes were also estimated. The total amount of EOR oil recoverable by the use of currently available EOR techniques is estimated to be about 1.5 billion barrels. Assuming that one-third of the potential target--500 million barrels--is recovered in the next thirty years, the present value of the state revenues (at an, eight percent discount rate) would be about 1.1 billion dollars. This is based on an inflation rate of five percent. Five other situations with varying crude oil prices and inflation rates were also investigated.

Oil recovery should be aided by CO2 development in southwestern Wyoming, scheduled to begin in 1987. As a result, CO2 floods may replace polymer floods as the process of choice in some fields.

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