An adaptive finite volume approach to simulation of precipitation and dissolution at the pore scale

Precipitation (or dissolution) of mineral grains modifies the geometry of the pore space in subsurface sediment with continuously evolving solid-liquid boundaries. In turn, changes in the pore space alter the groundwater flow through the sediment, which ultimately affects the continuum scale reaction rates that are relevant for field applications such as carbon sequestration. Modeling provides a unique tool to understand and quantify the feedback processes between mineral precipitation (or dissolution) and flow at the pore scale. Higher-order algorithms based on adaptive mesh refinement and finite volume methods have been successfully applied to flow and transport in complex microscale geometries such as microarray channels. Here, we couple a geochemical module that includes aqueous complexation and mineral reactions to these new flow and transport methods found in the Chombo software package. We have also extended this framework to track moving solid-fluid interfaces as a result of mineral reactions. This approach is consistent with those used for moving fluid-fluid interfaces, providing a robust and algorithmically consistent methodology for multiphase flow. We show that these advanced methods offer a promising alternative for reactive pore scale modeling through simulations of single pore throats as well as packed beds.