Simulation of three-dimensional viscoelastic deformation coupled to porous fluid flow

Omlin, Samuel; Räss, Ludovic; Podladchikov, Y. Y.

doi:10.1016/j.tecto.2017.08.012

Cited by 56 publications

(29 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The computed solutions may not be accurate, and non-linear features may be under-resolved. An alternative solution is to fully couple fluid flow and Stokes matrix flow in a single solver (Scott 1988;Stevenson & Scott 1991;Morency et al 2007;Dymkova & Gerya 2013;Keller et al 2013;Dannberg & Heister 2016;Zheng et al 2016;Omlin et al 2017b). Further, none of the previous studies, with the exception of Omlin et al (2017b), have considered decompaction weakening while coupling Darcian and Stokes flows in 3-D.…”

Section: Multiphysics Couplingmentioning

confidence: 99%

Resolving hydromechanical coupling in two and three dimensions: spontaneous channelling of porous fluids owing to decompaction weakening

Räss

Duretz

Podladchikov

2019

Geophysical Journal International

Self Cite

104

View full text Add to dashboard Cite

Fingering, veining, channelling and focussing of porous fluids are widely observed phenomena in the Earth's interior, driving a range of geo-processes across all scales. While observations suggest fairly localized flow patterns induced by fractures, the classical Darcian model predicts diffusive behaviour that leads to never-ending spreading and delocalization. We here investigate an alternative physical mechanism without the need to involve fractures. Decompaction weakening leads to the formation and propagation of localized flow-pathways in fluid-saturated porous media. We numerically solve the coupled equations using high-resolution 2-D and 3-D numerical modelling to predict non-linear porous flow in a non-linearly viscously deforming matrix. We show that high-porosity channels may be a dynamic and natural outcome of sufficiently resolved hydromechanical coupling and decompaction weakening. We propose an efficient solution strategy that involves an iterative pseudo-transient numerical method to solve the coupled system of equations in a matrix-free fashion. We discuss benefits and limitations of this approach that performs optimally on hardware accelerators such as graphical processing units and is well-suited for supercomputing. We benchmark the pseudo-transient routines against commonly used direct-iterative solving strategies and show convergence towards identical results. Furthermore, we use the fast solver to systematically study in 2-D the high-porosity channel propagation velocity as a function of bulk and shear viscosity ratios and report discrepancy between 2-D and 3-D configurations. We conclude that the fluid-flow rate in the channels is up to three orders of magnitude higher than expected by pure Darcian flow regimes and show that the high-porosity channels occurrence remains with strain rate dependant shear viscosity. We provide both the 2-D MATLAB-based direct-iterative and pseudo-transient routines for full reproducibility of the presented results and suggest our model configuration as a key benchmark case to validate the implementation of hydromechanical coupling in 2-D and 3-D numerical codes. The routines are available from Bitbucket and the Swiss Geocomputing Centre website, and are also supporting information to this paper.

show abstract

Section: Multiphysics Couplingmentioning

confidence: 99%

Resolving hydromechanical coupling in two and three dimensions: spontaneous channelling of porous fluids owing to decompaction weakening

Räss

Duretz

Podladchikov

2019

Geophysical Journal International

Self Cite

104

View full text Add to dashboard Cite

show abstract

“…Stevenson (1989) carried out a linear stability analysis and found conditions at which flow instabilities may arise, which may result in different 3-D shapes like elongated pockets, channels or porosity waves (Richardson, 1998;Wiggins and Spiegelman, 1995). Formation of 3-D channels within a deforming matrix has been demonstrated in Omlin et al (2018) or Räss et al (2014). Here we focus on the supersolidus source region and in particular on the dynamics of porosity waves.…”

Section: Introductionmentioning

confidence: 99%

“…where η s is the effective shear viscosity of the matrix, η b the bulk viscosity, η s0 the intrinsic shear viscosity of the matrix, C a constant of order 1, ϕ the porosity, and m = 0 for equal shear and bulk viscosities or m = 1 otherwise. There are also recent models that use more complex pressure-dependent weakening viscosities, but they still use the simplified equations mentioned above for the porosity dependence of the viscosity (Omlin et al, 2018;Yarushina et al, 2015). Schmeling et al (2012) developed an effective viscosity model depending on a simplified geometry of the fluid phase within a viscous matrix.…”

Section: Introductionmentioning

confidence: 99%

The effect of effective rock viscosity on 2-D magmatic porosity waves

2019

View full text Add to dashboard Cite

Abstract. In source regions of magmatic systems the temperature is above solidus, and melt ascent is assumed to occur predominantly by two-phase flow, which includes a fluid phase (melt) and a porous deformable matrix. Since McKenzie (1984) introduced equations for two-phase flow, numerous solutions have been studied, one of which predicts the emergence of solitary porosity waves. By now most analytical and numerical solutions for these waves used strongly simplified models for the shear- and bulk viscosity of the matrix, significantly overestimating the viscosity or completely neglecting the porosity dependence of the bulk viscosity. Schmeling et al. (2012) suggested viscosity laws in which the viscosity decreases very rapidly for small melt fractions. They are incorporated into a 2-D finite difference mantle convection code with two-phase flow (FDCON) to study the ascent of solitary porosity waves. The models show that, starting with a Gaussian-shaped wave, they rapidly evolve into a solitary wave with similar shape and a certain amplitude. Despite the strongly weaker rheologies compared to previous viscosity laws, the effects on dispersion curves and wave shape are only moderate as long as the background porosity is fairly small. The models are still in good agreement with semi-analytic solutions which neglect the shear stress term in the melt segregation equation. However, for higher background porosities and wave amplitudes associated with a viscosity decrease of 50 % or more, the phase velocity and the width of the waves are significantly decreased. Our models show that melt ascent by solitary waves is still a viable mechanism even for more realistic matrix viscosities.

show abstract

“…Wiggins and Spiegelman, 1995]. On the other hand, formation of 3D channels due to two-phase porous flow within a deforming matrix were demonstrated in [Omlin et al, 2018;Räss et al, 2014].…”

Section: Some Points For Improvementmentioning

confidence: 99%

“…In fact, much more complicated relations for pressure-dependent weakening viscosity were considered in some recent works of [Omlin et al, 2018;. Moreover, Omlin et al [2018] study the effect of the ratio of bulk and shear viscosities on the speed of wave propagation. The implication of this to magmatic systems can be important.…”

Section: C2mentioning

confidence: 99%

Review on the manuscript "The effect of effective rock viscosity on 2D magmatic porosity waves"

Yarushina¹

2019

Preprint

View full text Add to dashboard Cite

show abstract

Simulation of three-dimensional viscoelastic deformation coupled to porous fluid flow

Cited by 56 publications

References 30 publications

Resolving hydromechanical coupling in two and three dimensions: spontaneous channelling of porous fluids owing to decompaction weakening

Resolving hydromechanical coupling in two and three dimensions: spontaneous channelling of porous fluids owing to decompaction weakening

The effect of effective rock viscosity on 2-D magmatic porosity waves

Review on the manuscript "The effect of effective rock viscosity on 2D magmatic porosity waves"

Contact Info

Product

Resources

About

Simulation of three-dimensional viscoelastic deformation coupled to porous fluid flow

Cited by 56 publications

References 30 publications

Resolving hydromechanical coupling in two and three dimensions: spontaneous channelling of porous fluids owing to decompaction weakening

Resolving hydromechanical coupling in two and three dimensions: spontaneous channelling of porous fluids owing to decompaction weakening

The effect of effective rock viscosity on 2-D magmatic porosity waves

Review on the manuscript &quot;The effect of effective rock viscosity on 2D magmatic porosity waves&quot;

Contact Info

Product

Resources

About

Review on the manuscript "The effect of effective rock viscosity on 2D magmatic porosity waves"