Reactive Interfaces in Direct Numerical Simulation of Pore-Scale Processes

Molins, Sergi

doi:10.2138/rmg.2015.80.14

Cited by 68 publications

(52 citation statements)

References 61 publications

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“…), as well as those of many synthetics play a critical role in controlling the physical properties of and processes in rocks (Emmanuel et al 2015;Navarre-Sitchler et al 2015;Royne and Jamtveit 2015, this volume), and the interaction between them and the fl uid that are stored, fl ow through, precipitate in (Stack 2015, this volume) and react with (Liu et al 2015;Molins 2015;Putnis 2015, this volume) them. The better we understand and can quantify those porous structures, the better will be our ability to model, understand and predict the evolution of geological environments, either under natural conditions or those such as CO 2 or radiological waste sequestration, or addition or removal of other fl uids from geological reservoirs.…”

Section: Discussionmentioning

confidence: 99%

Characterization and Analysis of Porosity and Pore Structures

Anovitz

Cole

2015

Reviews in Mineralogy and Geochemistry

849

480

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Section: Discussionmentioning

confidence: 99%

Characterization and Analysis of Porosity and Pore Structures

Anovitz

Cole

2015

Reviews in Mineralogy and Geochemistry

849

480

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“…In porous media simulations, the feedback between precipitation and reactive surface area is often accounted for using constitutive relationships that decrease reactive surface area as the pore space is reduced (Garcia‐Rios et al, ; Molins, ). Our preliminary results suggest that the application of these relationships to fracture surfaces is not appropriate because precipitation increases the lateral extent, and surface area, of the reactive minerals.…”

Section: Discussionmentioning

confidence: 99%

Mineral Precipitation in Fractures: Using the Level‐Set Method to Quantify the Role of Mineral Heterogeneity on Transport Properties

Jones

Detwiler

2019

Water Resources Research

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We used a depth‐averaged reactive transport model to simulate transport of a supersaturated fluid through fractures and considered two models of precipitation‐induced surface alterations: (1) a localized 1‐D alteration of the surface and (2) a 3‐D alteration of the surface using the level‐set method. Comparing simulation results to a simple analytical solution for precipitation in a homogeneous (aperture and mineralogy) fracture demonstrated both models predict the alteration process reasonably well. However, comparing simulation results from both models to results from a recent experimental study of precipitation in a mineralogically heterogeneous fracture (Jones & Detwiler, 2016, https://doi.org/10.1002/2016GL069598) demonstrated that the ability of the 3‐D model to predict mineral growth across the aperture and in the fracture plane leads to much better agreement with the experimental observations. To quantify the role of reaction kinetics on the precipitation process, we ran additional simulations using the 3‐D evolution model for reaction rate constants ranging over 3 orders of magnitude. When the kinetics were much faster than the advective flux through the fracture, precipitation was focused near the inlet, which led to a transition from preferential flow near the inlet to more uniform flow near the outlet. When reaction kinetics were slow relative to advection, reaction sites grew uniformly throughout the fracture leading to the eventual formation of a single preferential flow path from inlet to outlet. Regardless of reaction rate, localization of precipitation reactions led to significant increases (3 to 20 times) in the time scale required to seal the fracture relative to a mineralogically homogeneous fracture.

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“…As a result, Darcy‐scale modeling studies often resort to using the reactive surface area as calibration parameter to match observations. In the pore‐scale approach, however, the reactive surface area is derived from the geometry of the mineral‐fluid interface and often, as done here, assumed to be equal to the physical area of this interface [ Molins , ]. Recent pore‐scale simulations using this assumption and literature‐derived rate parameters have shown good agreement to data from single calcite grain experiments [ De Baere et al ., ] and grain pack experiments [ Molins et al ., ].…”

Section: Model Descriptionmentioning

confidence: 99%

“…While gridding schemes that conform to the domain boundary, e.g., unstructured grid methods, can capture complex interface geometries by appropriate meshing strategies, remeshing is required when solid‐fluid interfaces evolve due to dissolution‐precipitation reactions. In contrast, structured‐mesh models require a method to represent the interfaces such as the immersed boundary method [ Benioug et al ., ] or the embedded boundary method [ Miller and Trebotich , ; Molins , ]. The embedded boundary method, which uses cut cells that result from intersecting the irregular fluid‐solid interfaces with structured Cartesian grids, makes it possible to take advantage of structured methods while capturing complex surficial geometries [ Trebotich et al ., ; Trebotich and Graves , ].…”

Section: Introductionmentioning

confidence: 99%

Mineralogical and transport controls on the evolution of porous media texture using direct numerical simulation

Molins

Trebotich

Miller

et al. 2017

Water Resources Research

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The evolution of porous media due to mineral dissolution and precipitation can change the bulk properties of subsurface materials. The pore‐scale structure of the media, including its physical and mineralogical heterogeneity, exerts controls on porous media evolution via transport limitations to reactive surfaces and mineral accessibility. Here we explore how these controls affect the evolution of the texture in porous media at the pore scale. For this purpose, a pore‐scale flow and reactive transport model is developed that explicitly tracks mineral surfaces as they evolve using a direct numerical simulation approach. Simulations of dissolution in single‐mineral domains provide insights into the transport controls at the pore scale, while the simulation of a fracture surface composed of bands of faster‐dissolving calcite and slower‐dissolving dolomite provides insights into the mineralogical controls on evolution. Transport‐limited conditions at the grain‐pack scale may result in unstable evolution, a situation in which dissolution is focused in a fast‐flowing, fast‐dissolving path. Due to increasing velocities, the evolution in these regions is like that observed under conditions closer to strict surface control at the pore scale. That is, grains evolve to have oblong shapes with their long dimensions aligning with the local flow directions. Another example of an evolving reactive transport regime that affects local rates is seen in the evolution of the fracture surface. As calcite dissolves, the diffusive length between the fracture flow path and the receding calcite surfaces increases. Thus, the calcite dissolution reaction becomes increasingly limited by diffusion.

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Reactive Interfaces in Direct Numerical Simulation of Pore-Scale Processes

Cited by 68 publications

References 61 publications

Characterization and Analysis of Porosity and Pore Structures

Characterization and Analysis of Porosity and Pore Structures

Mineral Precipitation in Fractures: Using the Level‐Set Method to Quantify the Role of Mineral Heterogeneity on Transport Properties

Mineralogical and transport controls on the evolution of porous media texture using direct numerical simulation

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