Guidelines for Designing Small-Scale Carbon Dioxide Enhanced Oil Recovery and Storage Pilot Projects

Commercial-scale enhanced oil recovery (EOR) pilots are designed for a few years of operation, with a relatively large volume of CO2 injected into several wells or patterns. The objective is to have direct field measurements of CO2 EOR and net/gross utilization and storage. Conversely, smaller, publicly funded, research-focused pilots target the collection of reservoir and production information over a shorter period on a limited budget and must rely on making CO2 EOR and storage estimates based on calibrated model projections. Moreover, many small-scale pilots are conducted where no infrastructure exists for CO2 delivery or injection via pipeline, leaving these pilots with a different set of operational requirements than a commercial project in a traditional CO2 EOR geographical area, such as West Texas. The Midwest Geological Sequestration Consortium (MGSC) conducted four small-scale CO2 storage pilot projects—three EOR and one enhanced coal bed methane (ECBM)—in the Illinois Basin. From these projects, guidelines were developed for site screening, selecting, and designing a CO2 storage research pilot that uses truck-delivered CO2, beginning with site selection and proceeding to the point of pilot start-up. The MGSC CO2 EOR pilots involved adapting developed sites at mature oil fields to the needs of a CO2 EOR project by installing portable CO2 injection and production equipment at the site. Geologic and reservoir modeling was conducted for all selected sites by using existing data to predict CO2 EOR and storage and the behavior of injected and in situ gas, oil, and CO2. Additionally, proper preparation ensured an effective monitoring, verification, and accounting program, which made it possible to safeguard the environmental health of the site and track the fate of the injected CO2. Although the research pilot guidelines in this paper are based on the MGSC CO2 EOR and ECBM pilots, these guidelines are also applicable to CO2 injection into brine-saturated formations.