ASSESSING LARGE-SCALE CO2 INJECTION AND MONITORING STRATEGIES IN CLOSED CARBONATE REEF RESERVOIRS IN MICHIGAN

Midwest Regional Carbon Sequestration Partnership (MRCSP) was established to assess how sequestration technologies can best be applied on a regional basis. A primary goal of the MRCSP Development Phase effort is to execute one-million metric ton scale CO₂ injection to evaluate best practices and technologies required to implement carbon sequestration on a commercial scale. The most practical opportunity for this test is in collaboration with Enhanced-Oil-Recovery (EOR) activities, which also allows research on concurrent utilization of CO₂. In the MRCSP region the CO₂ for such large-scale injection is available from Antrim-shale gas processing plants located in northern lower-peninsula of Michigan. Some of this CO₂ is already being utilized for oil production in nearby pinnacle carbonate reefs. These reef structures are in various stages of life-cycle, including pre-production reefs, reefs in primary production or tertiary EOR stage, and post-EOR reefs. The development phase effort involves a detailed assessment of CO₂ injection and flow in these closed reservoirs through extended site characterization, modeling, and monitoring. The nearly depleted reefs are at a low pressure and have infrastructure of wells, seismic and log data that makes them suitable for research on modeling and monitoring technologies during reef repressurization and injection above and just below the oil-water contact. 400,000 metric tons of CO₂ injection into a nearly depleted reef will be monitored using reservoir pressure, borehole seismic, natural and/or introduced tracers, geochemical analysis, and surface deformation analysis. New characterization and baseline monitoring data through advanced logs, vertical seismic profiling, saturation profiles, microseismic, and surface elevations also are being collected. Lessons learned from initial injection will be used to develop monitoring in subsequent reef structures to understand CO₂ migration in reservoirs, interaction with surrounding media, geochemical and geomechanical impacts, and storage capacity.