Pore-scale modeling of coupled homogeneous nucleation and reactive flow in porous matrix

The dynamic behavior of nucleation and precipitation of minerals in porous media during underground fluid injection has a significant impact on many engineering applications, such as shale gas extraction and CO2 sequestration. Traditional models usually overlook the role that homogeneous nucleation plays in this reactive flow process. Our study developed a novel numerical solver, ReactiveParticulateFlowFoam, which couples the homogeneous nucleation of minerals and the flow of reactive crystal particles at the pore scale for the first time. By simulating the reactive flow in microchannels and porous media, we found that the homogeneous nucleation behavior of minerals is governed by both the fluid flow conditions and the porous media structure. Our results indicate that an optimal Péclet number range exists that maximizes the homogeneous nucleation rate and the final amount of nuclei. In addition, the homogeneous nucleation is also affected by the porosity of the porous matrix, an increase in porosity enhances the number of nuclei, especially under advection-dominated conditions. Furthermore, we have discovered that, in advection-dominated regimes, high tortuosity of pore structure promotes homogeneous nucleation by enhancing local mixing through flow disturbance. This model provides a novel framework for the precise regulation of mineral homogeneous nucleation and precipitation, offering critical insights for the optimization of related geological engineering processes.