Evaluation of Technology and Policy Issues Associated with the Storage of Carbon Dioxide via Enhanced Oil Recovery in Determining the Potential for Carbon Negative Oil

Numerous legal and regulatory frameworks in the U.S. and globally are acknowledging the opportunity for greenhouse gas (GHG) emissions reductions offered by combining the long-term storage of CO 2 in association with carbon dioxide enhanced oil recovery (CO 2 -EOR), to support carbon capture and storage (CCS) as a climate mitigation technology. These include the U.S. Environmental Protection Agency (USEPA), the International Organization for Standardization (ISO), the State of California, and the Intergovernmental Panel on Climate Change (IPCC), among many. In this paper, a brief overview is provided of the literature on GHG lifecycle analyses (LCA) applied to CO 2 storage in association with CO 2 -EOR. Then, various techniques for performing LCA related to CO 2 -EOR operations are summarized. Moreover, since most past LCA analyses of CO 2 -EOR projects were generally based on historical CO 2 -EOR operations, LCA based on assumptions from these operations are likely not to represent future emissions reduction opportunities where CO 2 storage is a co-objective with increased oil production. Thus, the paper examines different CO 2 -EOR development options that could greatly increase the amount of CO 2 injected, and ultimately stored, to recover incremental oil via the application of CO 2 -EOR, and speculates on how even greater storage efficiencies with CO 2 -EOR can be realized. Assuming historically-based values for CO 2 utilization, most life cycle analyses of CO 2 storage in association with CO 2 -EOR show that the emissions associated with producing, processing, transporting and/or utilizing the incremental oil produced are greater than the CO 2 injected and stored in association with CO 2 -EOR. However, current CO 2 -EOR operations are achieving much higher utilization values, and assuming the wide-scale application of “next generation” technologies applied to existing and potential new resource targets, even larger utilization values are realizable. Recent work by Advanced Resources, for example, shows that “next generation” CO 2 -EOR applied to the main pay zone (MPZ) of oil reservoirs uses, on average , about 0.45 metric tons per barrel of oil produced, while CO 2 -EOR applied to the residual oil zone (ROZ) underlying and in between existing oil fields uses, on average , about 0.50 metric tons per barrel of oil produced. Many projects are likely to achieve even higher values of CO 2 utilization for CO 2 -EOR. These utilization values are over double that assumed in most traditional LCA analyses applied to CO 2 -EOR operations. And even greater utilization values are realizable. For comparison, emissions associated with the production, transport, refining, and ultimate combustion of the incremental oil produced are estimated to be on the order of 0,42 to 0.43 metric tons per barrel. Given these values for CO 2 utilization with CO 2 -EOR, accounting for emissions associated with CO 2 -EOR operations, with activities downstream of CO 2 -EOR operations (i.e., crude oil transport and refining), and even accounting for the combustion of fuels created from the barrel of crude, the amount of CO 2 injected and stored in the reservoir during CO 2 -EOR can generally be greater than that associated with the emissions associated with the incremental oil produced. Going forward, it will be important that legal and regulatory frameworks for verifying and accounting for GHG emissions reductions acknowledge the importance of CO 2 storage with CO 2 -EOR in achieving GHG emissions goals.