Mechanistic Understanding of Rhenium Electrodeposition Via High-Throughput Experimentation

One of the key risks associated with long term storage of CO₂ is the integrity and continuity of the confining strata. In a carbon storage project area, the presence of faults that transect both the storage and confining strata can be a significant risk that could allow leakage of injected CO₂ into shallow groundwater aquifers. Two-dimensional (2D) seismic is an effective source of data to evaluate the subsurface for the presence of faults.

The Illinois Storage Corridor project is a United States Department of Energy supported Carbon Storage Assurance Facility Enterprise (CarbonSAFE) project that consists of the subsurface characterization of two different sites in Illinois: The One Earth Energy site in Ford and McClean counties, and the Prairie State Generating Company (PSGC) site in Washington County, which is the subject of this study. As part of the subsurface characterization of the PSGC site, a characterization well, Lively Grove #1, was drilled in 2021. The storage complex penetrated by the well consists of two sandstone reservoirs separated by a dolomite, with an overlying ductile shale as the primary containment interval. After the well was drilled, a 2D seismic survey was also acquired in 2021 that consisted of three lines totaling 25 linear miles. The storage complex intervals display a robust seismic response due to the strong impedance contrasts between adjacent strata.

Interpretation of the 2021 2D seismic data reveals the presence of a fault complex that transects both the storage and confining intervals. The fault complex is interpreted as a strike-slip fault with a component of reverse offset indicated by a small positive flower structure, with a later phase of minor extension. Because it was observed on only one 2021 2D seismic line, the orientation and extent of the complex was unknown. In order to better characterize this fault complex, as well as to characterize a larger area for carbon storage around the project site, additional 2D seismic was acquired and interpreted in 2022. Eight additional lines were acquired totaling 76 linear miles.

The 2022 2D seismic data was able to constrain the extent and likely orientation of the previously identified fault complex. The survey also identified two more faults that transect both the storage and containment intervals: a small normal fault and another strike-slip fault. Taken together, the 2021 and 2022 2D seismic surveys have identified three specific locations within the project area that may have an elevated risk of CO₂ containment due to faulting. Further technical work will be needed to quantify this risk, and determine how and if this risk will impact the placement of CO₂ injection wells across the project area.