Computational modeling of calcite cementation in saline limestone aquifers: a phase-field study

Abstract

Abstract The present article investigates the effect of initial grain size on the overall growth kinetics during calcite cementation from supersaturated geothermal fluid whilst tracking the grain boundary behavior of the evolving microstructure using a multiphase-field model. In order to define rhombohedral calcite geometry, we consider a faceted-type surface energy anisotropy and validate the crystal shape using volume preservation technique in three dimensions. Next, we perform calcite growth simulations with multiple grains in 2D as well as 3D in order to computationally mimic the anisotropic cement overgrowths as observed in saline limestone aquifers. A significant deviation in the 3D overgrowth kinetics is observed as compared to 2D. The increase in cement overgrowths is found to be inversely dependent (non-linear) on the initial grain size. Moreover, the grain size distributions obtained from the numerically cemented microstructural data tend to get statistically dispersed and horizontally shifted with increasing mean grain size. Finally, the capability of present modeling approach in simulating dynamics of calcite cementation in 3D is demonstrated based on post-processing analyses and advanced visualization techniques.

Keywords

• Calcite cementation
• Multiphase-field model
• Overgrowth kinetics
• Grain size effect