2009 Portland GSA Annual Meeting (18-21 October 2009)

Paper No. 19
Presentation Time: 9:00 AM-6:00 PM

EVOLUTION OF PERMEABILITY BY PRECIPITATES


GHEZZEHEI, Teamrat, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, TAGhezzehei@ucmerced.edu

Subsurface chemical and biological transformations often influence fluid flow by altering the pore space morphology and related hydrologic properties such as porosity and permeability. In most coupled-processes models changes in porosity are inferred from geochemical and biological process models using mass-balance. The corresponding evolution of permeability is estimated using (semi-) empirical porosity-permeability functions such as the Kozeny-Carman equation or power-law functions. These equations typically do not account for the heterogeneous spatial distribution and morphological irregularities of the geochemical precipitates and biomass. As a result, predictions of permeability evolution are generally unsatisfactory. In this communication, we demonstrate the significance of pore-scale precipitate distribution on porosity-permeability relations using high resolution simulations of fluid flow through a single pore interspersed with crystals. The results of this study point to the need for a fully coupled multiscale approach for describing evolution of flow properties.