Multi-Stage X-Ray Imaging Dataset of Phase Trapping in Porous Media

Subsurface gas storage, particularly the sequestration of CO₂, continues to remain an active area of research for mitigating atmospheric CO₂ concentrations. However, experimental datasets providing direct, high-resolution measurements of CO₂ transport, saturation, and pore-scale dynamics under realistic reservoir conditions remain limited, due primarily to experimental complexity. In this study, we present a comprehensive dataset from supercritical CO₂ (scCO₂)-brine core-flooding experiments conducted at relevant subsurface conditions, employing a sophisticated core holder system capable of sustaining high-pressure and high-temperature environments within an X-ray microcomputed tomography (µCT) setup. Continuous monitoring of flow rates and system pressures accompanied X-ray imaging performed at equilibrium conditions, capturing fluid saturations with a high spatial resolution of 25 µm. scCO₂-equilibrated brine was utilized to minimize mass-transfer effects, and both drainage and imbibition scenarios are thoroughly documented. The unique dataset includes high-resolution 3D raw and segmented X-ray images detailing the dry and fluid-saturated conditions, complemented by quantitative metrics of fluid saturation, morphological descriptors, and phase connectivity. In addition, dual-quality X-ray image sets of high- and low-noise scans captured at residual scCO₂ saturation after imbibition are provided, enabling comparative analysis and advancements in rapid image-acquisition techniques. The detailed pressure histories and segmented morphological data facilitate advanced numerical model validation and serve as a benchmark dataset for image segmentation algorithm development. All data have been curated and uploaded to an open-access repository, promoting broad usability and fostering innovation in subsurface gas storage research.