HR: 11:35h
AN: H42A-06    [Abstracts]
TI: Pore-Network Approach for Upscaling Continuum Reactive Transport Equations
AU: * Tsimpanogiannis, I N
EM: ioannis@lanl.gov
AF: Los Alamos National Laboratory, MS T003, Los Alamos, NM 87545 United States
AU: Lichtner, P C
EM: lichtner@lanl.gov
AF: Los Alamos National Laboratory, MS T003, Los Alamos, NM 87545 United States
AU: Lu, C
EM: clu@lanl.gov
AF: Los Alamos National Laboratory, MS T003, Los Alamos, NM 87545 United States
AB: Conventional continuum models that rely on volume averages are typically used to describe the temporal and spatial evolution of multiphase flow and reaction within porous media (e.g. transport and reaction of soil contaminants, subsurface combustion for enhanced oil recovery, CO2 sequestration in geologic media, waste disposal, hydrothermal systems, and mineral deposits). The constitutive equations that are required for problem closure, such as mineral reaction rates, are obtained from laboratory experiments that are often conducted in batch reactor systems in the absence of a porous medium. However, pore-scale spatial heterogeneities could affect the validity of such an approach. Therefore, it is essential to delineate the range of applicability of laboratory measurements before they can be used directly in continuum models. To answer these issues requires a better understanding of reaction phenomena at the pore scale. In this work, a pore-network model is used to investigate upscaling from the pore to continuum scale. In this study we have modified the reactive flow and transport code FLOTRAN to accommodate a pore network model for fully saturated conditions. FLOTRAN is based on continuum scale mass and energy conservation equations in porous media, and takes into account reactive transport equations that describe multi-component chemical reactions. Such reactions can result in dissolution and precipitation of minerals thereby affecting the porosity and permeability of the formation. This study investigates the effect of spatial heterogeneity of mineral surface areas on reaction rates.
DE: 1830 Groundwater/surface water interaction
DE: 1832 Groundwater transport
DE: 1847 Modeling
DE: 3610 Geochemical modeling (1009, 8410)
SC: Hydrology [H]
MN: Fall Meeting 2005