(772b) Defining CO2 Storage Options in the Upper Ohio River Valley – Advanced Characterization of Geologic Reservoirs and Caprocks Authors: Caitlin Mcneil (Presenter

Development of Carbon Dioxide Capture, Utilization, and Storage (CCUS) technologies represents one of the most important components in the portfolio of options for greenhouse gas reduction. The emerging international consensus under mechanisms such as the Paris Accord and the possibility of future federal or state regulations for limiting CO₂ emissions essentially rule out continued use of coal as a power source in the future without implementation of CCUS technology. The upper Ohio River Valley region including eastern Ohio has a strong history of coal production and a dependence on coal for its industrial base, which includes power generation and steel manufacturing. However, the potential reservoirs and containment zones for CO₂ storage in the area are very poorly understood due to lack of deep well data. Thus, knowledge of capacity, containment security, and injectivity is rudimentary at best and a sustained effort is needed to map the deep geology and quantify the storage potential in the region. This project attempts to start developing a CO₂ storage framework using pre-existing and new data on potential storage reservoirs and containment intervals to estimate CO₂ storage resources in eastern Ohio. The geologic data were compiled from oil and gas well logs and cores available at the Ohio Division of Geological Survey, purchase of seismic data, and through collaboration with brine-injection well operators in eastern Ohio to collect advanced well logs and operational data. The available information was used to construct cross-sections and maps of formations depths, thickness, and porosity across the study area. Based on these maps, the prospective storage resources were estimated. The porosity and limited available permeability data were used to develop preliminary numerical reservoir models in selected areas to evaluate the feasibility of sustained injection. Finally, caprocks were evaluated using geomechanical and reservoir modeling methods to determine their effectiveness for containing injected CO₂. The project findings were disseminated to the stakeholders at various venues.

The overall findings of the work show that there is significant CO₂ storage potential in eastern Ohio based on porosity estimates. This is also proven by the presence of a number of high-performance injection wells in the region. The storage resource is vertically diversified into a number of geologic layers, both carbonates and sandstones, and is laterally heterogeneous. This heterogeneous nature means that advanced characterization and sustained geologic characterization using advanced tools is needed to improve confidence in storage estimates and long-term injectivity. The assessment also indicates that the primary caprock for the Cambrian-Ordovician reservoirs in the area has appropriate characteristics to retain the injected CO₂. In this study, the focus of the caprock analysis was limited to assessing the sealing effectiveness and mechanical integrity of the two geologic units immediately overlying the reservoirs [i.e., immediately overlying the Knox Unconformity], the Black River Group and the Wells Creek Formation, even though there are hundreds to thousands of feet of additional low permeability limestone and shale (Trenton Formation, Point Pleasant/Utica) above these units. Thus, the caprock analysis is conservative because it doesn’t take into consideration the entire caprock system.

This project has been conducted under grant agreement D-13-22 funded by Ohio Development Services Agency’s Ohio Coal Development Office and the Midwestern Regional Carbon Sequestration Partnership (MRCSP) led by Battelle with US Department of Energy funding. The project also benefited significantly through collaboration with a number brine injection well operators, who allowed access to their wells for collection of critical geologic characterization and injection operation data. The present project complements a number of past and ongoing efforts to prove CO₂ storage and utilization options in Ohio and surrounding regions.