Upscaling geochemical reaction rates using pore-scale network modeling

Li, Li; Peters, Catherine A.; Celia, Michael A.

doi:10.1016/j.advwatres.2005.10.011

Cited by 300 publications

(260 citation statements)

References 77 publications

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“…Does mineral precipitation take place uniformly within the porous medium, or do gradients in precipitation rate, and thus aqueous chemistry, develop? It is highly likely that they do, as demonstrated by such studies as those of Li et al [2006]. Even at the single pore scale, gradients may develop under certain conditions, although Li et al [2008] demonstrated that for typical groundwater flow rates, gradients within single pores were unlikely.…”

Section: Introductionmentioning

confidence: 87%

Upscaling calcium carbonate precipitation rates from pore to continuum scale

et al. 2012

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The upscaling of calcite precipitation rates in porous media from the pore (micron) to continuum (centimeter) scale is evaluated with an integrated experimental and modeling approach. Experiments using cylindrical cores packed with glass beads and calcite (Iceland spar) crystals were injected over a period of 28 days with a supersaturated mixture of CaCl 2 and NaHCO 3 to induce calcite growth. Bulk rates of precipitation based on the change in aqueous chemistry over the length of the column are compared with spatially resolved determinations of carbonate precipitation using X-ray synchrotron microtomographic imaging at the micron scale. These data are supplemented by continuously-stirred reactor experiments using the same calcite seed material so as to minimize differences in the effects of reactive site density of the seed material, and to evaluate the rate of precipitation in the absence of transport or "porous medium" effects. Calcite precipitation rates determined in the stirred flowthrough reactor in this study are considerably slower than rates determined at similar supersaturation in unseeded batch experiments by Tang et al. [2008a], although these rates are compatible with those reported in Nehrke et al. [2007] for precipitation on Iceland spar when the same normalization to reactive surface area is used. The nearly linear dependence of the rates on supersaturation cannot be attributed to a diffusion control in the case of the stirred reactors and is likely the result of multi-sourced spiral growth.Integrated precipitation rates based on column effluent chemistry from a higher supersaturation experiment are in good agreement with determinations of total carbonate precipitated based on determination of pre-and post-experiment mass in the column using X-ray microtomography. Using the rates of precipitation determined in the well-stirred flowthrough reactors, it is possible to match the spatially-resolved microtomographic and aqueous data with a coarser resolution continuum model using volume-averaged flow and reactive surface area if the generation of new reactive surface area is accounted for. A nucleation or surface roughening event, which is most pronounced within two millimeters of the column inlet where the supersaturation is highest, is recorded by both BET analysis, which indicates an increase in specific surface area from 0.012 m 2 •g -1 to a value of 0.21 m 2 •g -1 for neoformed calcium carbonate, and by X-ray microtomography. The best fit of the column X-ray microtomography data is provided by simulating calcite precipitation either as a single nearly linear rate for multi-sourced spiral growth, or as two parallel rates that include the spiral growth model and a 2D heterogeneous nucleation model modified by a partial diffusion control, although nucleation needs to be relatively minor on a mass basis in order to match the data. The combined experiments and modeling indicate that it is possible to develop upscaled quantitative models for porous media reactivity, but changes in such propert...

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Section: Introductionmentioning

confidence: 87%

Upscaling calcium carbonate precipitation rates from pore to continuum scale

et al. 2012

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“…These include: the mixed-cell method (MCM) [e.g., Acharya et al, 2005;Bryntesson, 2002;Kim et al, 2011;Li et al, 2006;Mehmani et al, 2012;Nogues et al, 2013], random walk [e.g., Sorbie and Clifford, 1991;Bruderer and Bernabe, 2001;Bijeljic et al, 2004;Jha et al, 2011], smoothed particle hydrodynamics (SPH) [e.g., Zhu and Fox, 2002], lattice Boltzmann (LB) [e.g., Kang et al, 2006], and classical Computational Fluid Dynamics (CFD) [e.g., Shen et al, 2011]. In this work, we employ MCM because of its overall simplicity and computational efficiency.…”

Section: Flow and Transport In Network Modelmentioning

confidence: 99%

A forward analysis on the applicability of tracer breakthrough profiles in revealing the pore structure of tight gas sandstone and carbonate rocks

Mehmani

Prodanović

et al. 2015

Water Resources Research

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We explore tracer breakthrough profiles (TBP) as a macroscopic property to infer the porespace topology of tight gas sandstone and carbonate rocks at the core scale. The following features were modeled via three-dimensional multiscale networks: microporosity within dissolved grains and pore-filling clay, cementation in the absence and presence of microporosity (each classified into uniform, porepreferred, and throat-preferred modes), layering, vug, and microcrack inclusion. A priori knowledge of the extent and location of each process was assumed to be known. With the exception of an equal importance of macropores and pore-filling micropores, TBPs show little sensitivity to the fraction of micropores present. In general, significant sensitivity of the TBPs was observed for uniform and throat-preferred cementation. Layering parallel to the fluid flow direction had a considerable impact on TBPs whereas layering perpendicular to flow did not. Microcrack orientations seemed of minor importance in affecting TBPs.

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“…These changes manifest themselves in the constitutive relations that characterize the continuum-scale properties of the soil and are used in the governing equations of flow and transport. An upscaling procedure has to be employed in order to treat pore-scale interactions of the fluid and the solid soil structure within the framework of continuum flow and transport models [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Effect of mineral reactions on the hydraulic properties of unsaturated soils: Model development and application

Wissmeier

Barry

2009

Advances in Water Resources

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT AbsThe selective radius shift model was used to relate changes in mineral volume due to precipitation/dissolution reactions to changes in hydraulic properties affecting flow in porous media. The model accounts for (i) precipitation/dissolution taking place only in the water-filled part of the pore space and further that (ii) the amount of mineral precipitation/dissolution within a pore depends on the local pore volume. The pore bundle concept was used to connect pore-scale changes to macroscopic soil hydraulic properties. Precipitation/dissolution induces changes in the pore radii of water-filled pores and, consequently, in the effective porosity. In a time step of the numerical model, mineral reactions lead to a discontinuous pore-size distribution because only the water-filled pores are affected. The pore-size distribution is converted back to a soil moisture characteristic function to which a new water retention curve is fitted under physically plausible constraints. The model equations were derived for the commonly used van Genuchten/Mualem hydraulic properties. Together with a mixed-form solution of Richards' equation for aqueous phase flow, the model was implemented into the geochemical modelling framework PHREEQC, thereby making available PHREEQC's comprehensive geochemical reactions. Example applications include kinetic halite dissolution and calcite precipitation as a consequence of cation exchange. These applications showed marked changes in the soil's hydraulic properties due to mineral precipitation/dissolution and the dependency of these changes on water contents. The simulations also revealed the strong influence of the degree of saturation on the development of the saturated hydraulic conductivity through its quadratic dependency on the van Genuchten parameter . Furthermore, it was shown that the unsaturated hydraulic conductivity at fixed reduced water content can even r tract increase du ing precipitation due to changes in the pore-size distribution.

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Upscaling geochemical reaction rates using pore-scale network modeling

Cited by 300 publications

References 77 publications

Upscaling calcium carbonate precipitation rates from pore to continuum scale

Upscaling calcium carbonate precipitation rates from pore to continuum scale

A forward analysis on the applicability of tracer breakthrough profiles in revealing the pore structure of tight gas sandstone and carbonate rocks

Effect of mineral reactions on the hydraulic properties of unsaturated soils: Model development and application

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