Assessing CO2 EOR Potential of Three Strategically Located Oil Fields in the Illinois Basin

Abstract

Carbon dioxide enhanced oil recovery (CO₂ EOR) has the potential to significantly increase production from mature oil fields in the Illinois Basin (ILB) while providing the additional benefit of storage of anthropogenic CO₂. However, there are currently no commercial CO₂ EOR operations in the ILB. The main challenges to implementation include negative perception of CO₂ EOR viability at ILB fields, absence of a CO₂ supply, and lack of infrastructure.

The absence of readily available CO₂ could be ameliorated by the development of commercial sources of anthropogenic CO₂. One potential source is located in Decatur, Illinois. The CO₂ compression equipment at an ethanol plant, which is currently used for CO₂ storage demonstration projects, could provide a commercial source of CO₂. A second source may become available in Coles County, Illinois, where there is ongoing interest in construction of a zero emissions power plant.

Successful field-scale, multi-year CO₂ EOR pilots are critical to gaining acceptance of CO₂ EOR in the ILB. The Illinois State Geological Survey recently evaluated the CO₂ EOR potential of three oilfields that are located near these potential CO₂ sources that might facilitate commercial demand for CO₂ EOR. The study included characterization of reservoir architecture, simulation of CO₂ EOR scenarios, experimental determination of minimum miscibility pressures (MMPs), and economic analysis of CO₂ EOR projections.

Results indicate that all three fields could be viable candidates for CO₂ EOR pilots. Different strategies were required for CO₂ EOR to be effective at each of the fields, leading to variation in results. The incremental oil produced as a result of CO₂ EOR ranged from 5.9 to 19% of the original oil in place over 15–20 years. The total amount of CO₂ stored ranged from 154,000 to 1,090,000 tons (140,000 to 993,000 tonnes). Net utilization of CO₂, or the amount of CO₂ stored divided by the incremental oil production, ranged from 1.4 to 6.4 mscf/stb. Economic analysis indicated that CO₂ EOR projects at these fields were likely to be profitable (depending on the development strategy) at oil prices exceeding $80bbl. In addition, the project facilitated dialogue between oilfield operators and potential suppliers of CO₂.

AAPG Datapages/Search and Discovery Article #90218 © 2015 Eastern Section Meeting, Indianapolis, Indiana, September 20-22, 2015