Supercritical CO2 intrusion into caprocks: insights from numerical simulation of lab-scale CO2 injection
Carbon capture and storage in deep geological formations suggests a promising large-scale CO2 mitigation option. Currently available pathways to meet the Paris climate goal of limiting global warming to well below 2 ºC involve significant contributions of geologic carbon storage. Nonetheless, this mitigation technology is not exempt from challenges. In particular, the potential CO2 leakage through the caprock is a major concern. CO2 is less dense than the in-situ brine in deep saline formations and tends to float. The upward migration of the buoyant CO2, if causing leakage through the caprock, can put at stake the large-scale implementation of geologic carbon storage. Therefore, the assessment of the caprock sealing capacity is of paramount importance. This study provides an improved understanding of CO2 flow mechanisms across the caprock based on insights gained from numerical simulations of core-scale CO2 injections. We inject supercritical CO2 into a caprock sample under representative subsurface conditions. We parameterize a two-phase flow model using laboratory data and reproduce the CO2 injection experiments. Overall, we conclude that advective CO2 flow is unlikely to take place through a caprock with sufficiently high capillary entry pressure and low intrinsic permeability. The ubiquitous molecular diffusion principally dominates CO2 leakage. These findings favor long-term storage of CO2 underground. Nevertheless, diffusive leakage over geological time scales has yet to be assessed through field-scale numerical simulations.
| Main Authors: | , , |
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| Other Authors: | |
| Format: | comunicación de congreso biblioteca |
| Language: | English |
| Published: |
2021-02
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| Subjects: | Supercritical CO2 intrusion into caprocks:, CO2 injection, |
| Online Access: | http://hdl.handle.net/10261/233052 |
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