Decision analysis and CO2–Enhanced oil recovery development strategies

This paper analyzes the relationship between actual reservoir conditions and predicted measures of performance of carbon dioxide enhanced oil recovery (CO₂–EOR) programs. It then shows how CO₂–EOR operators might maximize the value of their projects by approaching implementation using a “flexible selective” pattern development strategy, where the CO₂–EOR program patterns are selectively developed based on site-specific reservoir properties. It also analyzes performance measures and economic consequences of utilizing a continuous CO₂ injection strategy intended to maximize CO₂ retention for a defined time period. “Net CO₂ utilization,” calculated as difference between the volumes of CO₂ injected and CO₂ recovered in the production stream divided by the oil produced, is a standard measure of CO₂–EOR carbon utilization, but it can be a misleading predictor of the actual CO₂ retained in the reservoir. Asset value can be added to a CO₂–EOR project by recognizing effects of variations in reservoir parameter values and basing incremental development decisions on those data. For policy analysts, the consequences of ignoring geologic variability within a reservoir that is a candidate for CO₂–EOR will likely be to substantially overestimate predicted adoption of CO₂–EOR in response to economic incentives. This result holds true whether the CO₂–EOR program objective is to maximize net value by maximizing oil production or maximize CO₂ storage with oil recovery.