Did you know that we could store the heat-trapping carbon dioxide (CO2) gas underground with geologic carbon sequestration (GCS)? Works by injecting CO2 into geologic formations such as saline aquifers that are saturated with brine, the deployment and development of this subsurface engineering process requires understanding of multiphase fluid flow in the opaque porous media. Nowadays, with the advances in X-ray microtomographic (MCT) imaging, we can visualize fluid configuration interior to the opaque porous media with the acquired grayscale data. In this talk, we present experimental results acquired using MCT for multiphase fluid flow experiments conducted under conditions relevant to GCS. We investigated the impact of heterogeneous regions within the cores and the saturation state of the brine on the invasion pattern of supercritical CO2 (scCO2). We found that even the mild core heterogeneity of our samples had a significant impact on the development of the flow pattern of scCO2, especially when coupled with a change in saturation state of the brine. Our findings inform the prediction of flow pathways at the early stage of injection for GCS, which contribute to the assessment of storage capacity and integrity.