Synchrotron-based pore-network modeling of two-phase flow in Nubian Sandstone and implications for capillary trapping of carbon dioxide
- Journal Article
Rights / licenseCreative Commons Attribution 4.0 International
Depleted oil fields in the Gulf of Suez (Egypt) can serve as geothermal reservoirs for power generation using a CO-Plume Geothermal (CPG) system, while geologically sequestering CO. This entails the injection of a substantial amount of CO into the highly permeable brine-saturated Nubian Sandstone. Numerical models of two-phase flow processes are indispensable for predicting the CO-plume migration at a representative geological scale. Such models require reliable constitutive relationships, including relative permeability and capillary pressure curves. In this study, quasi-static pore-network modelling has been used to simulate the equilibrium positions of fluid–fluid interfaces, and thus determine the capillary pressure and relative permeability curves. Three-dimensional images with a voxel size of 0.65 of a Nubian Sandstone rock sample have been obtained using Synchrotron Radiation X-ray Tomographic Microscopy. From the images, topological properties of pores/throats were constructed. Using a pore-network model, we performed a sequential primary drainage, main imbibition cycle of quasi-static invasion in order to quantify (1) the CO and brine relative permeability curves, (2) the effect of initial wetting-phase saturation (i.e. the saturation at the point of reversal from drainage to imbibition) on the residual-trapping potential, and (3) study the relative permeability-saturation hysteresis. The results improve our understanding of the potential magnitude of capillary trapping in Nubian Sandstone, essential for future field-scale simulations. Show more
Journal / seriesInternational Journal of Greenhouse Gas Control
Pages / Article No.
SubjectPore-network modelling; Carbon capture and storage; CO2-plume geothermal; Nubian Sandstone (Egypt); Residual trapping
Organisational unit09494 - Saar, Martin O. / Saar, Martin O.
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Is supplemented by: https://doi.org/10.3929/ethz-b-000377881
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