Geological carbon sequestration relies on the efficient conversion of injected supercritical CO2 into dissolved CO2, a process accelerated by density-driven convection. Yet, most assessments still consider the subsurface as homogeneous, offering limited guidance for the layered and heterogeneous architectures typical of sedimentary basins. Building on this shortcoming, this work examines how stratigraphic structure -- such as homogeneous, randomly layered, stochastic, positive rhythmic, reverse rhythmic, coarse-first, and fine-first formations -- governs the onset and efficiency of convective dissolution. Using a two-dimensional model, this work tracks the dissolved-to-total CO2 mass fraction and relate system-scale kinetics to plume morphology. The findings reveal that stratigraphy exerts first-order control on both the timing and mode of CO2 transformation. Architectures with high-permeability pathways near the top, or those with strong small-scale heterogeneity, trigger early convection, promote vertically continuous fingering, and accelerate dissolution relative to a homogeneous benchmark. Randomly layered formations that divert flow produce moderate slowdowns. In contrast, low-permeability caps suppress vertical exchange, favor lateral spreading, and substantially delay conversion; coarse-first formations exhibit early lateral channeling that retards late-time mixing. Overall, the distribution of permeability in the upper reservoir and the scale of heterogeneity jointly control convective onset and dissolution efficiency, providing actionable guidance for formation screening, well placement, and monitoring horizons in geological carbon sequestration projects.
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Open Access
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In order to examine the heterogeneous nucleation and growth dynamics of mineral precipitation in reactive transport systems, as well as the evolution of key upscaling parameters, such as porosity and permeability, this study employs a model that integrates pore-scale reactive transport with arbitrary Lagrangian-Eulerian method. This model incorporates a heterogeneous probabilistic nucleation process based on classical nucleation theory, which is used to parametrically simulate the nucleation and growth processes of individual mineral particles within the reactive transport. The findings indicate that fluid velocity, along with nucleation and mineral growth rates, plays critical roles in determining the pattern and spatial distribution of precipitates. Nucleation promotes irregularities in the precipitate pattern and reduces the influence of flow on the spatial distribution of precipitate formation across particle surfaces. Precipitation on the surface of a single mineral particle within a pore channel is more accurately governed by a power law model, which captures the evolutionary relationship between porosity and permeability in porous media with periodic structures.
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