scholarly journals Clay mineral reactivity in the critical zone: exploring emergent coupled processes using the reactive transport code CrunchClay

2021 ◽  
Author(s):  
Christophe Tournassat ◽  
Carl Steefel
Keyword(s):  
Clay Mineral ◽  
Reactive Transport ◽  
Critical Zone ◽  
Coupled Processes ◽  
Transport Code ◽  
Mineral Reactivity

scholarly journals A parallelization scheme to simulate reactive transport in the subsurface environment with OGS#IPhreeqc

2015 ◽  
Vol 8 (3) ◽  
pp. 2369-2402
Author(s):  
W. He ◽  
C. Beyer ◽  
J. H. Fleckenstein ◽  
E. Jang ◽  
O. Kolditz ◽  
...  
Keyword(s):  
Message Passing ◽  
Reactive Transport ◽  
Message Passing Interface ◽  
Transport Processes ◽  
Coupled Processes ◽  
Scientific Software ◽  
Geochemical Reactions ◽  
Optimized Allocation ◽  
And Performance ◽  
The One

Abstract. This technical paper presents an efficient and performance-oriented method to model reactive mass transport processes in environmental and geotechnical subsurface systems. The open source scientific software packages OpenGeoSys and IPhreeqc have been coupled, to combine their individual strengths and features to simulate thermo-hydro-mechanical-chemical coupled processes in porous and fractured media with simultaneous consideration of aqueous geochemical reactions. Furthermore, a flexible parallelization scheme using MPI (Message Passing Interface) grouping techniques has been implemented, which allows an optimized allocation of computer resources for the node-wise calculation of chemical reactions on the one hand, and the underlying processes such as for groundwater flow or solute transport on the other hand. The coupling interface and parallelization scheme have been tested and verified in terms of precision and performance.

On the constitutive equations for coupled chemical reaction and deformation of porous rocks

2021 ◽  
Author(s):  
Yury Podladchikov ◽  
Viktoriya Yarushina ◽  
Benjamin Malvoisin
Keyword(s):  
Fluid Flow ◽  
Chemical Reactions ◽  
Constitutive Equations ◽  
Reactive Transport ◽  
Coupled Processes ◽  
Stable Phase ◽  
Precipitation Process ◽  
Porous Rocks ◽  
Mineral Growth ◽  
Reactive Surfaces

<p>Deformation, chemical reactions, and fluid flow in the geological materials are coupled processes. While some reactions are thought to be a consequence of fluid assisted dissolution on the stressed mineral surfaces and precipitation on the free surface, other reactions are caused by mineral replacement wherein a less stable mineral phase is replaced by a more stable phase, involving a change in solid volume and build-up of stresses on grain contacts, also known as a force of crystallization. Most of the existing models of chemical reactions coupled with fluid transport either assume dissolution-precipitation process or mineral growth in rocks. However, dissolution-precipitation models used together with fluid flow modelling predict a very limited extent of reaction hampered by pore clogging and blocking of reactive surfaces, which will stop reaction progress due to the limited supply of fluid to reactive surfaces. Yet, field observations report that natural rocks can undergo 100% hydration/carbonation. Mineral growth models, on the other hand, preserve solid volume but do not consider its feedback on porosity evolution. In addition, they predict the unrealistically high force of crystallization on the order of several GPa that must be developed in minerals during the reaction. Here, using a combination of effective media theory and irreversible thermodynamics approaches, we propose a new model for reaction-driven mineral expansion, which preserves porosity and limits unrealistically high build-up of the force of crystallization by allowing inelastic failure processes at the pore scale. To fully account for the coupling between reaction, deformation, and fluid flow we derive macroscopic poroviscoelastic stress-strain constitute laws, that account for chemical alteration and viscoleastic deformation of porous rocks. These constitutive equations are then used to simulate the reactive transport in porous rocks.</p>

Coupling between Thermo-Hydro-Chemical reactive transport and Gibbs minimisation: magma evolution in evolving multiphase porous media

2020 ◽  
Author(s):  
Annelore Bessat ◽  
Sébastien Pilet ◽  
Stefan M. Schmalholz ◽  
Yuri Podladchikov
Keyword(s):  
Gibbs Energy ◽  
Reactive Transport ◽  
Viscous Medium ◽  
Physical Aspect ◽  
Magma Evolution ◽  
Energy Minimisation ◽  
Transport Code ◽  
Low Degree ◽  
Melt Percolation ◽  
Alkaline Magmas

<p>The formation of alkaline magmas observed worldwide requires that low degree-melts, potentially formed in the asthenosphere, were able to cross the overlying lithosphere. Fracturing in the upper, brittle part of the lithosphere may help to extract this melt to the surface. However, the mechanism of extraction in the lower, ductile part of the lithosphere is still contentious. Metasomatic enrichment of the lithospheric mantle demonstrates that such low-degree melts interact with the lithosphere, but the physical aspect of this process remains unclear. The aim of this study is to better understand the percolation of magma in a porous viscous medium at pressure (P) and temperature (T) conditions relevant for the base of the lithosphere. We study such melt percolation numerically with a Thermo-Hydro-Chemical model of reactive transport coupled with thermodynamic data obtained via Gibbs energy minimisation. We perform Gibbs energy minimisation with Matlab using the linprog algorithm. We start with a simple ternary system of Forsterite/Fayalite/Enstatite solids and melts. All variables are a function of T, P and composition of the system (C), and are computed in both the Gibbs energy minimisation and in the reactive transport code, and can therefore vary freely.</p>

Presentation and use of a reactive transport code in porous media

2007 ◽  
Vol 32 (1-7) ◽  
pp. 507-517 ◽  
Author(s):  
Ph. Montarnal ◽  
C. Mügler ◽  
J. Colin ◽  
M. Descostes ◽  
A. Dimier ◽  
...  
Keyword(s):  
Porous Media ◽  
Reactive Transport ◽  
Transport Code

Recent advances in time-lapse, laboratory rock physics for the characterization and monitoring of fluid-rock interactions

Geophysics ◽  
2015 ◽  
Vol 80 (2) ◽  
pp. WA49-WA59 ◽  
Author(s):  
Tiziana Vanorio
Keyword(s):  
Surface Area ◽  
Reactive Transport ◽  
High Surface ◽  
High Surface Area ◽  
Rock Physics ◽  
Time Lapse ◽  
Coupled Processes ◽  
Recent Advances ◽  
Rock Microstructure ◽  
Fluid Interactions

Monitoring thermo-chemo-mechanical processes geophysically — e.g., fluid disposal or storage, thermal and chemical stimulation of reservoirs, or natural fluids simply entering a new system — raises numerous concerns because of the likelihood of fluid-rock chemical interactions and our limited ability to decipher the geophysical signature of coupled processes. One of the missing links is understanding the evolution of seismic properties together with reactive transport because rock properties evolve as a result of chemical reactions and vice versa. Capturing this coupling experimentally is one of the missing elements in the existing literature. This paper describes recent advances in rock-physics experiments to understand the effects of dissolution-induced compaction on acoustic velocity, porosity, and permeability. This paper has a dual aim: understanding the mechanisms underlying permanent modifications to the rock microstructure and providing a richer set of experimental information to inform the formulation of new simulations and rock modeling. Data observation included time-lapse experiments and imaging tracking transport and elastic properties, the rock microstructure, and the pH and chemical composition of the fluid permeating the rock. Results show that the removal of high surface area, mineral phases such as microcrystalline calcite and clay appears to be mostly responsible for dissolution-induced compaction. Nevertheless, it was the original rock microstructure and its response to stress that ultimately defined how solution-transfer and rock compaction feed back upon each other. The change in pore volume to the applied stress, the permeability characterizing the formation, and the reactive transport of phases characterized by a high surface area were strongly coupled during injection, controlling how velocity evolved. In less stiff rocks, rock-fluid interactions led to grain-slip-driven compaction and a consequent decrease in velocity. In tight and stiff rocks, rock-fluid interactions led to minimal compaction, a larger increase in permeability, and crack opening. Nevertheless, the change in velocity of these tight rocks was almost negligible.

scholarly journals Addressing numerical challenges in introducing a reactive transport code into a land surface model: a biogeochemical modeling proof-of-concept with CLM–PFLOTRAN 1.0

2016 ◽  
Vol 9 (3) ◽  
pp. 927-946 ◽  
Author(s):  
Guoping Tang ◽  
Fengming Yuan ◽  
Gautam Bisht ◽  
Glenn E. Hammond ◽  
Peter C. Lichtner ◽  
...  
Keyword(s):  
Land Surface ◽  
Reactive Transport ◽  
Computing Time ◽  
Reaction Network ◽  
Transformation Method ◽  
Residual Concentration ◽  
Log Transformation ◽  
Time Stepping ◽  
Transport Code ◽  
Scaling Methods

Abstract. We explore coupling to a configurable subsurface reactive transport code as a flexible and extensible approach to biogeochemistry in land surface models. A reaction network with the Community Land Model carbon–nitrogen (CLM-CN) decomposition, nitrification, denitrification, and plant uptake is used as an example. We implement the reactions in the open-source PFLOTRAN (massively parallel subsurface flow and reactive transport) code and couple it with the CLM. To make the rate formulae designed for use in explicit time stepping in CLMs compatible with the implicit time stepping used in PFLOTRAN, the Monod substrate rate-limiting function with a residual concentration is used to represent the limitation of nitrogen availability on plant uptake and immobilization. We demonstrate that CLM–PFLOTRAN predictions (without invoking PFLOTRAN transport) are consistent with CLM4.5 for Arctic, temperate, and tropical sites.Switching from explicit to implicit method increases rigor but introduces numerical challenges. Care needs to be taken to use scaling, clipping, or log transformation to avoid negative concentrations during the Newton iterations. With a tight relative update tolerance (STOL) to avoid false convergence, an accurate solution can be achieved with about 50 % more computing time than CLM in point mode site simulations using either the scaling or clipping methods. The log transformation method takes 60–100 % more computing time than CLM. The computing time increases slightly for clipping and scaling; it increases substantially for log transformation for half saturation decrease from 10−3 to 10−9 mol m−3, which normally results in decreasing nitrogen concentrations. The frequent occurrence of very low concentrations (e.g. below nanomolar) can increase the computing time for clipping or scaling by about 20 %, double for log transformation. Overall, the log transformation method is accurate and robust, and the clipping and scaling methods are efficient. When the reaction network is highly nonlinear or the half saturation or residual concentration is very low, the allowable time-step cuts may need to be increased for robustness for the log transformation method, or STOL may need to be tightened for the clipping and scaling methods to avoid false convergence.As some biogeochemical processes (e.g., methane and nitrous oxide reactions) involve very low half saturation and thresholds, this work provides insights for addressing nonphysical negativity issues and facilitates the representation of a mechanistic biogeochemical description in Earth system models to reduce climate prediction uncertainty.

scholarly journals Computational Microfluidics for Geosciences

2021 ◽  
Vol 3 ◽  
Author(s):  
Cyprien Soulaine ◽  
Julien Maes ◽  
Sophie Roman
Keyword(s):  
Porous Media ◽  
Reactive Transport ◽  
Laboratory Experiments ◽  
State Of The Art ◽  
Coupled Processes ◽  
High Resolution Imaging ◽  
Future Trends ◽  
Pore Scale ◽  
Resolution Imaging ◽  
Fundamental Equations

Computational microfluidics for geosciences is the third leg of the scientific strategy that includes microfluidic experiments and high-resolution imaging for deciphering coupled processes in geological porous media. This modeling approach solves the fundamental equations of continuum mechanics in the exact geometry of porous materials. Computational microfluidics intends to complement and augment laboratory experiments. Although the field is still in its infancy, the recent progress in modeling multiphase flow and reactive transport at the pore-scale has shed new light on the coupled mechanisms occurring in geological porous media already. In this paper, we review the state-of-the-art computational microfluidics for geosciences, the open challenges, and the future trends.

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