Geometry and mineral heterogeneity controls on precipitation in fractures: An X-ray micro-tomography and reactive transport modeling study

The processes that affect reorganization of flow and transport in fractures during precipitation were investigated experimentally numerically order to highlight the interplay between calcite precipitation, growth substrate. Calcite was precipitated from a supersaturated solution at two different rates (0.4 or 12 cm3·hr−1) into artificial made dolomitic limestone. Although inlet fluid composition temperature identical for all experiments, facture sealing patterns closely linked mineral substrate, fracture geometry field reorganization. rate is highly variable along paths depends on local saturation index reactive fluid. In addition, precipitates preferentially comparatively dolomite 2D modeling accounting negative feedback porosity permeability decrease succeeded quantitatively reproducing experimental observations, such as evolution void obtained X-ray micro-tomography (XMT), calcium breakthrough concentration sealing. corresponding model then used evaluate impacts reactivity randomly generated anisotropic geometries. Simulation results reveal capacity associated Damköhler number, i.e., ratio characteristic times advective reaction, although other factors like kinetic law play also role this stage. More importantly, existence critical initiating onto substrate can substantially impair prediction capacity, will depend spatial heterogeneity connectivity Most cases result strong gradient direction increase anisotropy. However, under certain conditions, allows recover more isotropic properties lead back uniform Negative process closure supports fluids geo-engineering operations.