Speaker
Description
Geological CO$_2$ storage can be successfully implemented in deep saline aquifers that have sufficient storage efficiency and are overlain by a competent sealing caprock. Constitutive functions that govern macroscale capillary pressure and relative permeability are central in constraining both storage efficiency of the formation and sealing properties of the caprock. Capillary pressure and relative permeability functions for porous systems are in part determined by wettability, which is a pore-scale phenomenon that has direct influence on macroscale displacement processes. While wettability of saline aquifers and caprocks are assumed to be remain water-wet when CO$_2$ is injected, there is recent intriguing evidence of contact angle change due to long-term exposure to CO$_2$. This phenomenon weakens the strength of capillary forces which subsequently alters capillary pressure and relative permeability functions dynamically over time.
Recently, new dynamic models have been developed for both capillary pressure and relative permeability functions that captures the impact of wettability alteration (WA) due to long-term CO$_2$ exposure. These dynamic macroscale saturation functions are driven by CO$_2$ exposure time that is calculated from the saturation history. In this paper, the dynamic functions are implemented into a two-phase two-component simulator to study the impact of long-term WA dynamics on field-scale CO$_2$ storage systems. We simulate horizontal migration patterns for CO$_2$ injection affected by WA dynamics for different flow regimes. Our results show that the impact of WA dynamics leads to a complex CO$_2$ migration behavior that is not captured by static saturation functions. Also, we find that storage efficiency can be described effectively by the capillary number. In addition, we simulate buoyancy-driven migration in the caprock caused by loss of containment due to dynamics WA. We develop scaling models for CO$_2$ migration into the caprock caused by dynamic wettability that show that long-term WA poses little risk to CO$_2$ containment over relevant timescales.
| Participation | Online |
|---|---|
| Country | Norway |
| MDPI Energies Student Poster Award | No, do not submit my presenation for the student posters award. |
| Time Block Preference | Time Block A (09:00-12:00 CET) |
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