Carbon capture and storage (CCS) is an important strategy for reducing greenhouse gas emissions by trapping carbon dioxide (CO₂) deep underground in rock formations. However, to safely and effectively store CO₂, scientists need to understand the pore spaces inside the rock where the gas will be injected and stored. This study focuses on the Lower Tuscaloosa Formation, a deep rock formation in the southeastern U.S., to investigate how these pore structures affect the rock’s ability to store and transmit fluids. We used high-resolution 3D imaging and computer modeling to analyze rock samples collected from over 7,700 feet below the surface. These tools allowed us to see the size, shape, and connectivity of the pores in detail. Our results showed that simply knowing how much pore space (porosity) the rock has is not enough to predict how easily fluids can move through it (permeability). Instead, how well the pores are connected plays a much bigger role. This research shows the importance of examining rock properties at pore scales to improve predictions of CO₂ storage performance. Our findings will help design more accurate and safer carbon storage strategies. The project was supported by the U.S. Department of Energy through the SECARB-USA initiative.