Implementation Strategies for Accurate and Efficient Control Volume-Based Two-Phase Hydrothermal Flow Solutions

Vehling, F.; Hasenclever, Jörg; Rüpke, Lars

doi:10.1007/s11242-017-0957-2

Cited by 7 publications

(12 citation statements)

References 31 publications

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“…f appears in equation (17). We use the finite volume method on the unstructured triangular finite element meshes (e.g., Vehling et al, 2018) to accumulate and advect methane until it is possibly released by hydrothermal venting at the top. We have benchmarked our implementation of sill cooling/crystallization, organic cracking, and dehydration against data from contact aureoles around a 10.4-m-thick dike (see supporting information S1).…”

Section: Conversion Of Organic Matter and Methane Generationmentioning

confidence: 99%

Distinct Degassing Pulses During Magma Invasion in the Stratified Karoo Basin—New Insights From Hydrothermal Fluid Flow Modeling

Galerne

Hasenclever

2019

Geochem Geophys Geosyst

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Magma emplacement in organic‐rich sedimentary basins is a main driver of past environmental crises. Using a 2‐D numerical model, we investigate the process of thermal cracking in contact aureoles of cooling sills and subsequent transport and emission of thermogenic methane by hydrothermal fluids. Our model includes a Mohr‐Coulomb failure criterion to initiate hydrofracturing and a dynamic porosity/permeability. We investigate the Karoo Basin, taking into account host‐rock material properties from borehole data, realistic total organic carbon content, and different sill geometries. Consistent with geological observations, we find that thermal plumes quickly rise at the edges of saucer‐shaped sills, guided along vertically fractured high‐permeability pathways. Contrastingly, less focused and slower plumes rise from the edges and the central part of flat‐lying sills. Using a novel upscaling method based on sill‐to‐sediment ratio, we find that degassing of the Karoo Basin occurred in two distinct phases during magma invasion. Rapid degassing triggered by sills emplaced within the top 1.5 km emitted ~1.6·103 Gt of thermogenic methane, while thermal plumes originating from deeper sills, carrying a 13‐times‐greater mass of methane, may not reach the surface. We suggest that these large quantities of methane could be remobilized by the heat provided by neighboring sills. We conclude that the Karoo large igneous province may have emitted as much as ~22.3·103 Gt of thermogenic methane in the half million years of magmatic activity, with emissions up to 3 Gt/year. This quantity of methane and the emission rates can explain the negative δ13C excursion of the Toarcian environmental crisis.

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Section: Conversion Of Organic Matter and Methane Generationmentioning

confidence: 99%

Distinct Degassing Pulses During Magma Invasion in the Stratified Karoo Basin—New Insights From Hydrothermal Fluid Flow Modeling

Galerne

Hasenclever

2019

Geochem Geophys Geosyst

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“…It remains a question of active research to assess to strengths and limitations of sequential versus coupled approaches in terms of efficiency, stability, and accuracy. The reader can find further discussion on this in Ingebritsen et al (2010), Vehling et al (2018).…”

Section: Motivation For a New Thermohaline Codementioning

confidence: 99%

“…enthalpy, and composition. Recently, we have presented a coupled pressure/enthalpy scheme simulating pure water multiphase flow (Vehling et al 2018). This method uses a higher-order time differencing scheme (thetatime differencing) that leads to higher accuracy, larger time step sizes, and a better convergence of the Newton-Raphson iteration scheme.…”

Section: Motivation For a New Thermohaline Codementioning

confidence: 99%

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Brine Formation and Mobilization in Submarine Hydrothermal Systems: Insights from a Novel Multiphase Hydrothermal Flow Model in the System H2O–NaCl

Vehling

Hasenclever²,

Rüpke

2020

Transp Porous Med

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Numerical models have become indispensable tools for investigating submarine hydrothermal systems and for relating seafloor observations to physicochemical processes at depth. Particularly useful are multiphase models that account for phase separation phenomena, so that model predictions can be compared to observed variations in vent fluid salinity. Yet, the numerics of multiphase flow remain a challenge. Here we present a novel hydrothermal flow model for the system H2O–NaCl able to resolve multiphase flow over the full range of pressure, temperature, and salinity variations that are relevant to submarine hydrothermal systems. The method is based on a 2-D finite volume scheme that uses a Newton–Raphson algorithm to couple the governing conservation equations and to treat the non-linearity of the fluid properties. The method uses pressure, specific fluid enthalpy, and bulk fluid salt content as primary variables, is not bounded to the Courant time step size, and allows for a direct control of how accurately mass and energy conservation is ensured. In a first application of this new model, we investigate brine formation and mobilization in hydrothermal systems driven by a transient basal temperature boundary condition—analogue to seawater circulation systems found at mid-ocean ridges. We find that basal heating results in the rapid formation of a stable brine layer that thermally insulates the driving heat source. While this brine layer is stable under steady-state conditions, it can be mobilized as a consequence of variations in heat input leading to brine entrainment and the venting of highly saline fluids.

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“…In addition, there are a number of geothermal modeling codes that can handle two-phase behavior that have not (yet) been adapted to handle the complex EOS of saltwater over sufficiently large pressure and temperature ranges. HYDROTHERM (Kipp et al, 2008), FEHM (Zyvoloski et al, 1997), HT2_NR (Vehling et al, 2018), and TOUGH2 (Pruess et al, 1999) are examples of such codes.…”

Section: Introductionmentioning

confidence: 99%

<i>HydrothermalFoam</i> v1.0: a 3-D hydro-thermo-transport model for natural submarine hydrothermal systems

Guo¹,

Rüpke²,

Tao³

2020

Preprint

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Abstract. Herein, we introduce HydrothermalFoam, a three dimensional hydro-thermo-transport model designed to resolve fluid flow within submarine hydrothermal circulation systems. HydrothermalFoam has been developed on the OpenFOAM platform, which is a Finite Volume based C++ toolbox for fluid-dynamic simulations and for developing customized numerical models that provides access to state-of-the-art parallelized solvers and to a wide range of pre- and post-processing tools. We have implemented a porous media Darcy-flow model with associated boundary conditions designed to facilitate numerical simulations of submarine hydrothermal systems. The current implementation is valid for single-phase fluid states and uses a pure water equation-of-state (IAPWS-97). We here present the model formulation, OpenFOAM implementation details, and a sequence of 1-D, 2-D and 3-D benchmark tests. The source code repository further includes a number of tutorials that can be used as starting points for building specialized hydrothermal flow models. The model is published under the GNU General Public License v3.0.

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Implementation Strategies for Accurate and Efficient Control Volume-Based Two-Phase Hydrothermal Flow Solutions

Cited by 7 publications

References 31 publications

Distinct Degassing Pulses During Magma Invasion in the Stratified Karoo Basin—New Insights From Hydrothermal Fluid Flow Modeling

Distinct Degassing Pulses During Magma Invasion in the Stratified Karoo Basin—New Insights From Hydrothermal Fluid Flow Modeling

Brine Formation and Mobilization in Submarine Hydrothermal Systems: Insights from a Novel Multiphase Hydrothermal Flow Model in the System H2O–NaCl

<i>HydrothermalFoam</i> v1.0: a 3-D hydro-thermo-transport model for natural submarine hydrothermal systems

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Implementation Strategies for Accurate and Efficient Control Volume-Based Two-Phase Hydrothermal Flow Solutions

Cited by 7 publications

References 31 publications

Distinct Degassing Pulses During Magma Invasion in the Stratified Karoo Basin—New Insights From Hydrothermal Fluid Flow Modeling

Distinct Degassing Pulses During Magma Invasion in the Stratified Karoo Basin—New Insights From Hydrothermal Fluid Flow Modeling

Brine Formation and Mobilization in Submarine Hydrothermal Systems: Insights from a Novel Multiphase Hydrothermal Flow Model in the System H2O–NaCl

&lt;i&gt;HydrothermalFoam&lt;/i&gt; v1.0: a 3-D hydro-thermo-transport model for natural submarine hydrothermal systems

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Product

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<i>HydrothermalFoam</i> v1.0: a 3-D hydro-thermo-transport model for natural submarine hydrothermal systems