GEOMECHANICAL CHARACTERIZATION OF THE CAMBRIAN CAPROCK FORMATIONS FOR CARBON STORAGE IN THE MICHIGAN BASIN

Carbon Capture, Utilization and Storage (CCUS) is a promising approach used to combat climate change. A key target for geological storage in the Michigan Basin is the Cambrian Mount Simon Sandstone, which has an estimated storage capacity between 26 and 109 billion metric tons of CO₂ (Leetaru et al, 2009). Immediately overlying the Mt. Simon are the Eau Claire, Dresbach, Franconia, and Trempealeau Formations, which have been considered the confining unit for the Mt Simon Formation, but their sealing capacity, mechanical stability, and spatial heterogeneity remain unknown. This project is funded by the U.S. Department of Energy under DE-FE0032368 and focuses on geomechanical properties and heterogeneity of the Cambrian caprocks in the Michigan basin. To capture geomechanical variability we utilize the new-generation instrumented scratch test (the WOMBAT testbench by EPSLog) that allows continuous core strength to be measured without significantly damaging the core. The strength data are then correlated to lithological and petrophysical data from the same core intervals. Preliminary data indicate significant strength variability, with much lower strength in the pink sandstone intervals than in the green-grey intervals with dolomitic cement. However, the direct strength correlation between wells is complicated by significant intraformational heterogeneity. The results of this work highlight the importance of detailed caprock characterization that captures heterogeneity and variability of caprock properties in carbon storage systems.