Of the viable strategies outlined by the Intergovernmental Panel on Climate Change (IPCC) for atmospheric emission reduction strategies and technologies, geological storage of CO2 (CO2 geo-sequestration) holds an enormous promise with the potential to have significant impacts on emissions and atmospheric CO2 reduction. Among various geological storage options, depleted oil and gas reservoirs are excellent candidates due to the availability of reservoir data and well characteristics from the hydrocarbon production period. However, predicting the behaviour of CO2 in reservoir rocks is challenging largely due to the complex interactions between various fluids and minerals, in particular in the presence of structural heterogeneities presented by real rocks.
The focus of this research is directed towards understanding the role of rock heterogeneity on the spatial distribution of CO2 in sandstone rocks. We present results from in-situ experiments, where sub-surface conditions are created in the lab to simulate CO2 geo-sequestration process. High resolution X-ray micro-computed tomography (XMCT) scans were acquired throughout our experiments to resolve pore scale features and fluid distribution in the system. The results obtained during my PhD research combine experiments, 2D-3D-4D imaging and simulations. Our results show that trapped CO2 in the rock is influenced by a range of structural and morphological features at the pore scale. We measure that rock heterogeneity has a significant impact on the connectivity of the CO2 phase, which consequently affects the storage capacity of the rock.