Multicomponent multiphase reactive fluid flow in viscoelastoplastic porous media: localization patterns of fluid flow and strain

2021 ◽  
Author(s):  
Lyudmila Khakimova ◽  
Nikolai Belov ◽  
Artyom Myasnikov ◽  
Anatoly Vershinin ◽  
Kirill Krapivin ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Reactive Transport ◽  
Transport Model ◽  
Shear Bands ◽  
Porous Matrix ◽  
Deformation Localization ◽  
Linear Free Energy ◽  
Constrained Minimization Problem ◽  
Spectral Finite Elements ◽  
The Impact

<p>This work is devoted to developing the self-consistent thermo-hydro-chemo-mechanical reactive transport model to predict and describe natural and industrial petroleum processes at different scales.</p><p>We develop a version of the front tracking approach for multicomponent multiphase flow in order to treat spontaneous splitting of discontinuities. We revisit the solution for the Riemann problem and systematically classify all possible configurations as functions of initial concentrations on both sides of the discontinuity. We validate the algorithm against finite volume high-resolution technics and high-order spectral finite elements.</p><p>To calculate the parameters of phase equilibria, we utilize an approach based on the direct minimization of the Gibbs energy of a multicomponent mixture. This method ensures the consistency of the thermodynamic lookup tables. The core of the algorithm is the non-linear free-energy constrained minimization problem, formulated in the form of a linear programming problem by discretization in compositional space.</p><p>The impact of the complex rheological response of porous matrix on the morphology of fluid flow and shear deformation localization is considered. Channeling of porosity waves and shear bands morphology and their orientation is investigated for viscoelastoplastic both shear and bulk rheologies.</p>

Investigation of Underground Bio-Methanation Using Bio-Reactive Transport Modeling

2021 ◽  
Author(s):  
Denis Sergeevich Nikolaev ◽  
Nazika Moeininia ◽  
Holger Ott ◽  
Hagen Bueltemeier
Keyword(s):  
Carbon Dioxide ◽  
Reactive Transport ◽  
Transport Model ◽  
Porous Media Flow ◽  
Potential Candidate ◽  
Field Scale ◽  
Reactive Transport Model ◽  
Demand Fluctuations ◽  
Gas Fields ◽  
The Impact

Abstract Underground bio-methanation is a promising technology for large-scale renewable energy storage. Additionally, it enables the recycling of CO2 via the generation of "renewable methane" in porous reservoirs using in-situ microbes as bio-catalysts. Potential candidate reservoirs are depleted gas fields or even abandoned gas storages, providing enormous storage capacity to balance seasonal energy supply and demand fluctuations. This paper discusses the underlying bio-methanation process as part of the ongoing research project "Bio-UGS – Biological conversion of carbon dioxide and hydrogen to methane," funded by the German Federal Ministry of Education and Research (BMBF). First, the hydrodynamic processes are assessed, and a review of the related microbial processes is provided. Then, based on exemplary field-scale simulations, the bio-reactive transport process and its consequences for operation are evaluated. The hydrogen conversion process was investigated by numerical simulations on field scale. For this, a two-phase multi-component bio-reactive transport model was implemented by (Hagemann 2018) in the open-source DuMux (Flemisch et al. 2011) simulation toolkit for porous media flow. The underlying processes include the transport of reactants and products, consumption of specific components, and the related growth and decay of the microbial population, resulting in a bio-reactive transport model. The microbial kinetic parameters of methanogenic reactions are taken from the available literature. The simulation study covers different scenarios on conceptional field-scale models, studying the impact of well placement, injection rates, and gas compositions. Due to a significant sensitivity of the simulation results to the bio-conversion kinetics, the field-specific conversion rates must be obtained. Thus, the Bio-UGS project is accompanied by laboratory experiments out of the frame of this paper. Other parameters are rather a matter of design; in the present case of depleted gas fields, those parameters are coupled and can be chosen to convert fully hydrogen and carbon dioxide to methane. Especially the well spacing can be considered the main design parameter in the likely case of a given injection rate and gas composition. This study extends the application of the previously developed code from a homogeneous-2D to the heterogeneous-3D case. The simulations mimic the co-injection of carbon dioxide and hydrogen from a 40 MW electrolysis.

scholarly journals Reactive transport model of kinetically controlled celestite to barite replacement

2021 ◽  
Vol 56 ◽  
pp. 57-65
Author(s):  
Morgan Tranter ◽  
Maria Wetzel ◽  
Marco De Lucia ◽  
Michael Kühn
Keyword(s):  
Reactive Transport ◽  
Oil And Gas ◽  
Prediction Models ◽  
Transport Model ◽  
Solid Phase ◽  
A Priori ◽  
Dissolution Kinetics ◽  
Input Concentration ◽  
Geochemical Model ◽  
The Impact

Abstract. Barite formation is of concern for many utilisations of the geological subsurface, ranging from oil and gas extraction to geothermal reservoirs. It also acts as a scavenger mineral for the retention of radium within nuclear waste repositories. The impact of its precipitation on flow properties has been shown to vary by many orders of magnitude, emphasising the need for robust prediction models. An experimental flow-through column setup on the laboratory scale investigating the replacement of celestite (SrSO4) with barite (BaSO4) for various input barium concentrations was taken as a basis for modelling. We provide here a comprehensive, geochemical modelling approach to simulate the experiments. Celestite dissolution kinetics, as well as subsequent barite nucleation and crystal growth were identified as the most relevant reactive processes, which were included explicitly in the coupling. A digital rock representation of the granular sample was used to derive the initial inner surface area. Medium (10 mM) and high (100 mM) barium input concentration resulted in a comparably strong initial surge of barite nuclei formation, followed by continuous grain overgrowth and finally passivation of celestite. At lower input concentrations (1 mM), nuclei formation was significantly less, resulting in fewer but larger barite crystals and a slow moving reaction front with complete mineral replacement. The modelled mole fractions of the solid phase and effluent chemistry match well with previous experimental results. The improvement compared to models using empirical relationships is that no a-priori knowledge on prevailing supersaturations in the system is needed. For subsurface applications utilising reservoirs or reactive barriers, where barite precipitation plays a role, the developed geochemical model is of great benefit as only solute concentrations are needed as input for quantified prediction of alterations.

scholarly journals Modeling the impact of soil aggregate size on selenium immobilization

2013 ◽  
Vol 10 (3) ◽  
pp. 1323-1336 ◽  
Author(s):  
M. F. Kausch ◽  
C. E. Pallud
Keyword(s):  
Reactive Transport ◽  
Temporal Dynamics ◽  
Transport Model ◽  
Soil Aggregates ◽  
Aggregate Size ◽  
Soil Aggregate ◽  
Drainage Water ◽  
Rate Equations ◽  
Advective Transport ◽  
The Impact

Abstract. Soil aggregates are mm- to cm-sized microporous structures separated by macropores. Whereas fast advective transport prevails in macropores, advection is inhibited by the low permeability of intra-aggregate micropores. This can lead to mass transfer limitations and the formation of aggregate scale concentration gradients affecting the distribution and transport of redox sensitive elements. Selenium (Se) mobilized through irrigation of seleniferous soils has emerged as a major aquatic contaminant. In the absence of oxygen, the bioavailable oxyanions selenate, Se(VI), and selenite, Se(IV), can be microbially reduced to solid, elemental Se, Se(0), and anoxic microzones within soil aggregates are thought to promote this process in otherwise well-aerated soils. To evaluate the impact of soil aggregate size on selenium retention, we developed a dynamic 2-D reactive transport model of selenium cycling in a single idealized aggregate surrounded by a macropore. The model was developed based on flow-through-reactor experiments involving artificial soil aggregates (diameter: 2.5 cm) made of sand and containing Enterobacter cloacae SLD1a-1 that reduces Se(VI) via Se(IV) to Se(0). Aggregates were surrounded by a constant flow providing Se(VI) and pyruvate under oxic or anoxic conditions. In the model, reactions were implemented with double-Monod rate equations coupled to the transport of pyruvate, O2, and Se species. The spatial and temporal dynamics of the model were validated with data from experiments, and predictive simulations were performed covering aggregate sizes 1–2.5 cm in diameter. Simulations predict that selenium retention scales with aggregate size. Depending on O2, Se(VI), and pyruvate concentrations, selenium retention was 4–23 times higher in 2.5 cm aggregates compared to 1 cm aggregates. Under oxic conditions, aggregate size and pyruvate concentrations were found to have a positive synergistic effect on selenium retention. Promoting soil aggregation on seleniferous agricultural soils, through organic matter amendments and conservation tillage, may thus help decrease the impacts of selenium contaminated drainage water on downstream aquatic ecosystems.

scholarly journals Modeling the impact of soil aggregate size on selenium immobilization

2012 ◽  
Vol 9 (9) ◽  
pp. 12047-12086 ◽  
Author(s):  
M. F. Kausch ◽  
C. E. Pallud
Keyword(s):  
Reactive Transport ◽  
Temporal Dynamics ◽  
Transport Model ◽  
Soil Aggregates ◽  
Aggregate Size ◽  
Soil Aggregate ◽  
Drainage Water ◽  
Rate Equations ◽  
Advective Transport ◽  
The Impact

Abstract. Soil aggregates are mm- to cm-sized microporous structures separated by macropores. Whereas fast advective transport prevails in macropores, advection is inhibited by the low permeability of intra-aggregate micropores. This can lead to mass transfer limitations and the formation of aggregate-scale concentration gradients affecting the distribution and transport of redox sensitive elements. Selenium (Se) mobilized through irrigation of seleniferous soils has emerged as a major aquatic contaminant. In the absence of oxygen, the bioavailable oxyanions selenate, Se(VI), and selenite, Se(IV), can be microbially reduced to solid, elemental Se, Se(0), and anoxic microzones within soil aggregates are thought to promote this process in otherwise well aerated soils. To evaluate the impact of soil aggregate size on selenium retention, we developed a dynamic 2-D reactive transport model of selenium cycling in a single idealized aggregate surrounded by a macropore. The model was developed based on flow-through-reactor experiments involving artificial soil aggregates (diameter: 2.5 cm) made of sand and containing Enterobacter cloacae SLD1a-1 that reduces Se(VI) via Se(IV) to Se(0). Aggregates were surrounded by a constant flow providing Se(VI) and pyruvate under oxic or anoxic conditions. In the model, reactions were implemented with double-Monod rate equations coupled to the transport of pyruvate, O2, and Se-species. The spatial and temporal dynamics of the model were validated with data from experiments and predictive simulations were performed covering aggregate sizes between 1 and 2.5 cm diameter. Simulations predict that selenium retention scales with aggregate size. Depending on O2, Se(VI), and pyruvate concentrations, selenium retention was 4–23 times higher in 2.5-cm-aggregates compared to 1-cm-aggregates. Under oxic conditions, aggregate size and pyruvate-concentrations were found to have a positive synergistic effect on selenium retention. Promoting soil aggregation on seleniferous agricultural soils, through organic matter amendments and conservation tillage, may thus help decrease the impacts of selenium contaminated drainage water on downstream aquatic ecosystems.

Instantaneous rock transformations in the deep crust driven by reactive fluid flow

2020 ◽  
Author(s):  
Andreas Beinlich ◽  
Timm John ◽  
Johannes C. Vrijmoed ◽  
Masako Tominaga ◽  
Tomas Magna ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Carbon Sequestration ◽  
Reactive Transport ◽  
Subduction Zones ◽  
Large Scale ◽  
Transport Model ◽  
Plate Motion ◽  
Tectonic Deformation ◽  
Reaction Fronts ◽  
Reactive Fluids

<p>Fluid–rock interactions link mass and energy transfer with large-scale tectonic deformation, drive the formation of mineral deposits, carbon sequestration, and rheological changes of the lithosphere. While spatial evidence indicates that fluid–rock interactions operate on length scales ranging from the grain boundary to tectonic plates, the timescales of regional fluid–rock interactions remain essentially unconstrained, despite being critically important for quantifying the duration of fundamental geodynamic processes. Here we show that reaction-induced transiently high permeability significantly facilitates fast fluid flow through low-permeability rock of the mid-crust. Using observations from an exceptionally well-exposed fossil hydrothermal system to inform a multi-element advective–diffusive–reactive transport model, we show that fluid-driven reaction fronts propagate with ~10 cm year<sup>-1</sup><sub>,</sub> equivalent to the fastest tectonic plate motion and mid-ocean ridge spreading rates. Consequently, in the presence of reactive fluids, large-scale fluid-mediated rock transformations in continental collision and subduction zones occur on timescales of tens of years, implying that natural carbon sequestration, ore deposit formation, and transient and long-term petrophysical changes of the crust proceed, from a geological perspective, instantaneously.</p>

The influence of bottom water intrusion events on the biogeochemistry of a coastal fjord

2020 ◽  
Author(s):  
Subhadeep Rakshit ◽  
Andrew Cogswell ◽  
Sebastian Haas ◽  
Emmanuel Devred ◽  
Richard Davis ◽  
...  
Keyword(s):  
Reactive Transport ◽  
Bottom Water ◽  
Water Exchange ◽  
Transport Model ◽  
Biogeochemical Processes ◽  
Low Oxygen ◽  
Eastern Canada ◽  
Oxygen Conditions ◽  
Bottom Waters ◽  
The Impact

<p>Lack of bottom water exchange in fjord-like estuaries can result in low oxygen conditions and creating sites of redox-sensitive biogeochemical processes, such as denitrification. In many of these systems, occasional intrusions of well-oxygenated bottom water may temporarily alter redox gradients and sediment-water biogeochemistry. Quantifying the magnitude and importance of these changes is a challenge due to the short timescales over which these events can occur. Here we present results from Bedford Basin, a 71 m deep coastal fjord in eastern Canada, where a 20-year, weekly timeseries of bottom water conditions indicates that autumn wind-driven intrusion events are a common, but infrequent, feature of its circulation. To examine the impact of these intrusions on biogeochemistry, we deployed a benthic instrument pod at 60 m depth to record high-resolution measurements of temperature, salinity, nitrate, oxygen, and fluorescence over a 4-month period during the fall of 2018.  During this time we captured two intrusion events, one in mid-Oct and another in mid-Nov. Both intrusion events occurred on a timescale of hours and resulted in sharp changes in temperature, salinity, oxygen, and nitrate.  We used these measurements to constrain a coupled sediment-water column reactive transport model to examine the immediate and annual impacts of these intrusion events on oxygen and nitrogen dynamics in the basin bottom waters and across the sediment-water interface.</p>

Reactive Transport Modelling applied to Ni laterite ore deposits in New Caledonia : Impact of discrete fractures on Ni mineralization

2021 ◽  
Author(s):  
Sylvain Favier ◽  
Yoram Teitler ◽  
Fabrice Golfier ◽  
Michel Cathelineau
Keyword(s):  
Fluid Flow ◽  
Reactive Transport ◽  
New Caledonia ◽  
Dual Porosity ◽  
Reactive Transport Modelling ◽  
Transport Modelling ◽  
Dual Porosity Model ◽  
The Impact ◽  
Porosity Model ◽  
2D Model

<p>Laterite nickel-ore formation in New Caledonia is classically assumed to be governed by supergene processes, and downward migration of waters with Ni-enrichment at the basis of the laterite profile. However, Ni-ore distribution's heterogeneity seems to have been favoured by secondary processes controlled by the combined effects of inherited tectonics, geomorphological evolution and hydrologic systems since the primary laterite formation. Fluid flow and mass transfer processes are not purely downward at low-temperature conditions, but can also be related to lateral fluid circulations, and local drainage along damaged zones in the vicinity of faults (Cathelineau et al., 2016a; 2016b; Myagkiy et al., 2019). This study aims to investigate through reactive transport modelling the impact of discrete fracture on the Ni distribution.</p><p><br>We simulate the dissolution of olivine profile where fractures are the main channels of the fluid-flow. Olivine dissolution is assumed to be kinetically controlled whereas the precipitation of secondary weathering products is considered to occur according to local equilibrium. Results from two different numerical approaches are presented and discussed. The first one is based on a 1D dual-porosity model of a vertically oriented column of serpentinized olivine using PhreeqC associated with the llnl.dat thermodynamic database. The second one is a 2D modelling of hydro-chemical processes in fractured porous media based on the coupling of PhreeqC and Comsol Multiphysics through ICP. While the 1D model aims to describe the general trend of the progression of the weathering front and the global mineral redistribution, the 2D model focuses on particular fracture geometry and hotspot moments of the dissolution process to highlight crucial transition and redistribution of the different mineral phases in relation with the spatial distribution of fractures.</p><p><br>In the 1D dual-porosity model, the fractures are modelled as advective cells connected to a diffusive cell containing the main part of olivine. Two different geochemical models are thus designed. The first one describes the fracture and the advective area's geochemical behaviour, while the second one focuses on the matrix in the diffusive area. The 2D model extends the work initiated by Myagkiy et al. (2019) on simple configurations. The fractures are modelled herein as 1D discrete surfaces interacting with a porous matrix of olivine. Different fracture configurations are studied to assess their impact on mineral redistribution.</p><p><br>Results from both modellings are then compared with observed field data from New Caledonia and previous modelling of an olivine profile without fractures (Myagkiy et al., 2017) to validate the models and highlight the differences induced by the fracture network.</p>

Colloidal Transport of Heavy Metals in Natural Subsurface Sediments

2021 ◽  
Author(s):  
Sema Sevinc Sengor
Keyword(s):  
Heavy Metals ◽  
Reactive Transport ◽  
Environmental Remediation ◽  
Transport Model ◽  
Transport Processes ◽  
Subsurface Water ◽  
Colloidal Transport ◽  
Subsurface Sediments ◽  
Oxide Minerals ◽  
The Impact

<p>Colloid particles are widely distributed in the environment. These colloids have recently been gaining significant attention due to their unique characteristics in environmental remediation pertaining to degradation, transformation and immobilization of contaminants in soils and aquifers. On the other hand, once mobilized by subsurface water flow, colloids may pose risks to surface water and groundwater quality as they are effective ‘‘carriers’’ of a variety of common contaminants found in water and soils. Therefore, understanding the transport mechanisms of the colloids and incorporation of colloidal transport processes in reactive transport models are crucial for successful applications of many remediation efforts in the subsurface. Fe (hydr)oxide colloidal compounds have large surface areas and high reactivity, which can lead to spontaneous adsorption of many pollutants. For the successful stabilization of pollutants, it is vital to understand the associated biogeochemical processes, and competitive effects of contaminant sorption onto these colloidal phases. This work focuses on the development of a mechanistic Fe(hydr)oxide based colloid-facilitated reactive transport model which identifies the impact of Fe(hydr)oxide colloids on the stability and mobility of heavy metals (Zn and Pb) in example<strong> </strong>subsurface sediments of Lake Coeur d’Alene (LCdA), USA. Key reactions include the mobilization of heavy metals initially sorbed onto the colloidal Fe(hydr)oxide minerals through microbial reductive dissolution. Precipitation of metal sulfides at depth as a result of biogenic sulfide production is also captured. The simulations compare the biogeochemical cycling of metals considering colloidal vs. immobile phases of Fe(hydr)oxide minerals in the lake sediments.</p>

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