Probabilistic Nucleation and Crystal Growth in Porous Medium: New Insights from Calcium Carbonate Precipitation on Primary and Secondary Substrates

Abstract

Knowledge of crystal nucleation and growth is paramount in understanding the geometry evolution of porous medium during reactive transport processes in geo-environmental studies. To predict transport properties precisely, it is necessary to delineate both the amount and location of nucleation and precipitation events in the spatiotemporal domain. This study investigates the precipitation of calcium carbonate crystals on a heterogeneous sandstone substrate as a function of chemical supersaturation, temperature, and time. The main objective was to evaluate solid formation under different boundary conditions when the solid−liquid interface plays a key role. New observations were made on the effect of primary and secondary substrates and the role of preferential precipitation locations on the rock surfaces. The results indicate that supersaturation and temperature determine the amount, distribution pattern, and growth rate of crystals. Substrate characteristics governed the nucleation, growth location, and evolution probability across time and space. Moreover, substrate surface properties introduced preferential sites that were occupied and covered with solids first. Our results highlight the complex dynamics induced by substrate surface properties on the spatial and temporal solute distribution, transport, and deposition. We accentuate the great potentials of the probabilistic nucleation model to describe mineral formation in a porous medium during reactive transport.

Dissolution-After-Precipitation (DAP): a simple microfluidic approach for studying carbonate rock dissolution and multiphase reactive transport mechanisms

“…Although the polymorphic transition pathways are deterministic at a fixed pressure and temperature, the exact location where crystal grains emerge is probabilistic. 45,46 Furthermore, the emerged grains can change the fluid flow field and thus impact later precipitation. Therefore, the exact spatial distribution of the grain population would be different for each experiment.…”

Clay Mineral Type and Content Control Properties of Fine-Grained CO2 Caprocks—Laboratory Insights from Strongly Swelling and Non-Swelling Clay–Quartz Mixtures

“…The ductile clay fractions in the fine-grained caprocks may also cover reactive solid surfaces, which leads to limited diffusion in the porous layers around the grains and hence limited (geo)chemical reactions [2]. This armoring phenomenon caused by clay minerals reshapes the available surface area for precipitation and dissolution (geo)chemical reactions during coupled thermo-hydro-mechanical-chemical (THMC) processes, leading to changes in the system's reactivity and reaction progress and rates [2,[85][86][87].…”

Precipitation-induced Geometry Evolution in Porous Media: Numerical and Experimental Insights based on New Model on Probabilistic Nucleation and Mineral Growth

“…Subsurface reactive fluid flow and solute transport is central to several pressing energy, environment, and societal challenges, including the geological storage of carbon dioxide (CO2). Mineral nucleation and growth is a prime example of interface-coupled dissolution and precipitation (ICDP) reactions giving rise to geometry evolution in porous media [1,[6][7][8][9][10][11]. When precipitation reactions are ample, crystal accumulations can dramatically reduce porosity (amount of void space) [8,10,12].…”

“…The reactive transport models (RTMs) only then can provide precise and realistic predictions on the intricate interplay between transport mechanisms and reaction kinetics and, therefore, advection-diffusion-reaction (ADR). However, accurately representing the dynamics and dimensionality of mineral nucleation and growth (or, in general, ICDP) in porous media is still challenging [8,9,12,13,[23][24][25][26]. The RTM complexity arises from the ADR dependence on multiple parameters, including fluid flow, fluid chemistry, and the mineral substrate that might vary notably over different time-and length-scales [3,9,[27][28][29][30][31][32].…”

“…However, accurately representing the dynamics and dimensionality of mineral nucleation and growth (or, in general, ICDP) in porous media is still challenging [8,9,12,13,[23][24][25][26]. The RTM complexity arises from the ADR dependence on multiple parameters, including fluid flow, fluid chemistry, and the mineral substrate that might vary notably over different time-and length-scales [3,9,[27][28][29][30][31][32]. Prediction of these complex perturbations requires RTMs that are often far from trivial because of the dynamic interplay of the several parameters in action simultaneously.…”