A Hybrid Experimental-Numerical Approach to Study the Evolution of Porous Media during Biomineralization.*

In this study, pore-scale characteristics of the interactions between biogeochemically induced carbonate precipitation and the accompanying impacts on the hydraulics properties of porous media are investigated by using a hybrid experimental-numerical approach. The experimental studies consist of a two-dimensional transparent microfluidic chip to visualize the biomineralization process at a pore-scale. A reactive solution is flushed in 10 cycles through the microfluidic chip while the process is recorded by time-sequential high-resolution imaging. The fluid flow response in the pore structure due to clogging was traced via dyed water injection and recording the video in the early stages of the fluid entrance to the pore structure and its percolation through the pore network. To obtain tempo-spatial characteristics of velocity fields affected by mineralization in the pore space, Particle Image Velocimetry (PIV) method is adopted by injecting fluorescent micro-sized spheres into the water saturated pore network. The experimental images were analyzed using a developed image processing algorithm to detect carbonate minerals within the pore space. Based on processed images, a finite element CFD model was developed to explore the impact of bioclogging on the hydrodynamics of the porous media including the evolution of pore structure morphology, porosity-permeability relations and of fluid percolation pathways.