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Unstable, Super Critical CO 2 -Water Displacement in Fine Grained Porous Media under Geologic Carbon Sequestration Conditions
In this study we investigated fluid displacement water with supercritical (sc) CO in chalk under conditions close to those used for geologic CO sequestration (GCS), to answer two main questions: How much volume is available for scCO injection? And what is the main mechanism of displacement over a ra...
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Published in: | Scientific reports 2019-08, Vol.9 (1), p.11272 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Online Access: | Get full text |
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Summary: | In this study we investigated fluid displacement water with supercritical (sc) CO
in chalk under conditions close to those used for geologic CO
sequestration (GCS), to answer two main questions: How much volume is available for scCO
injection? And what is the main mechanism of displacement over a range of temperatures? Characterization of immiscible scCO
displacement, at the pore scale in the complex microstructure in chalk reservoirs, offers a pathway to better understand the macroscopic processes at the continuum scale. Fluid behavior was simulated by solving the Navier-Stokes equations, using finite-volume methods within a pore network. The pore network was extracted from a high resolution 3D image of chalk, obtained using X-ray nanotomography. Viscous fingering dominates scCO
infiltration and pores remain only partially saturated. The unstable front, developed with high capillary number, causes filling of pores aligned with the flow direction, reaching a maximum of 70% scCO
saturation. The saturation rate increases with temperature but the final saturation state is the same for all investigated temperatures. The higher the saturation rate, the higher the dynamic capillary pressure coefficient. A higher dynamic capillary pressure coefficient indicates that scCO
needs more time to reach capillary equilibrium in the porous medium. |
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ISSN: | 2045-2322 |