InterPore2026

Salt Precipitation during CO₂ Injection: Insights from Quasi-1D Validation and 3D Pore-Network Modelling

22 May 2026, 09:50

15m

Oral Presentation (MS09) Pore-Scale Physics and Modeling MS09

Speaker

Yuxi Liang

Description

During CO₂ injection into saline aquifers, evaporation occurs at gas–brine interfaces, resulting in increased salinity and the potential for salt precipitation. At the pore scale, precipitated salt progressively reduces pore and throat radii, impairing permeability and injectivity during CO₂ storage.

We develop a pore-network modelling framework to investigate salt precipitation during CO₂ injection. The model explicitly accounts for gas-phase vapour transport, liquid-phase mass balance, salt concentration, and the dynamic modification of pore and throat radii due to precipitation. To establish physical consistency and numerical robustness, the framework is first examined using quasi-one-dimensional (1D) pore networks, where evaporation rates, cumulative water loss, and salt accumulation can be directly benchmarked against analytical expressions.

The quasi-1D simulations reproduce evaporation-controlled drying behaviour and capture the temporal evolution of liquid saturation and salt concentration. Salt precipitation is observed to initiate near the advancing dry front, governed by the local balance between vapour removal and water availability. These results provide a quantitative reference for assessing mass conservation, transport consistency, and sensitivity to injection rate and transport parameters, forming a robust baseline for more complex network geometries.

The framework is subsequently extended to three-dimensional (3D) pore networks representing Bentheimer sandstone and other rocks to explore the influence of network connectivity, spatial heterogeneity, and gas invasion pathways on salt precipitation patterns. In 3D networks, salt accumulation is spatially heterogeneous and strongly correlated with gas accessibility and the intensity of local evaporation. Precipitation preferentially localises within highly connected regions and flow-controlling throats, forming clustered salt deposits that are associated with pronounced permeability reduction.

By combining quasi-1D validation with 3D pore-network analysis, this work provides pore-scale insight into salt precipitation processes during CO₂ injection and their implications for injectivity. The modelling framework offers a flexible platform for investigating injection scenarios and assessing pore-scale mitigation strategies in saline aquifers.