Mineral precipitation-induced porosity reduction and its effect on transport parameters in diffusion-controlled porous media
Abstract
In geochemically perturbed systems where porewater and mineral assemblages are unequilibrated
the processes of mineral precipitation and dissolution may change important transport properties such as porosity
and pore diffusion coefficients. These reactions might alter the sealing capabilities of the rock by complete pore-
scale precipitation (cementation) of the system or by opening new migration pathways through mineral dissolution.
In actual 1D continuum reactive transport codes the coupling of transport and porosity is generally accomplished
through the empirical Archie’s law. There is very little reported data on systems with changing porosity under well
controlled conditions to constrain model input parameters. In this study celestite (SrSO4
) was precipitated in the pore
space of a compacted sand column under diffusion controlled conditions and the effect on the fluid migration prop
-
erties was investigated by means of three complementary experimental approaches: (1) tritiated water (HTO) tracer
through diffusion, (2) computed micro-tomography (μ-CT ) imaging and (3) post-mortem analysis of the precipitate
(selective dissolution, SEM/EDX).
Origin : Publisher files allowed on an open archive
Loading...