Porous plate experiments are performed on consolidated sandstone cores to measure the end-point residual super-critical carbon dioxide saturation as a function of the initial carbon dioxide saturation. Standard 1.5 inch diameter core samples are fully saturated with brine prior to unsteady state super-critical carbon dioxide injection to reach the initial condition. At this point a saturation reading is performed or water flooding commences to reach the residual saturation. The saturation readings are performed by dropping the pore phase pressure and measuring the fluid expansion. The experimental procedure is repeated for different consolidated sandstone cores. The cores are characterised with porosity, permeability and pore size distribution measurements. The characterisation parameters are used to explain the end-point residual saturation results. By using this experimental approach sandstone characteristics preferential for high degrees of residual phase super-critical carbon dioxide trapping are identified. In geological carbon dioxide storage in aquifers and oilfields, the injected super-critical phase is unlikely to reach its maximum saturation in the pore space. Injecting brine to trap the carbon dioxide is one way to quickly render it immobile. This study implies that this process may allow a significant fraction of the injected carbon dioxide to be trapped, making this an effective long-term storage process.
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