Modeling hydrofracture

Flekkøy, Eirik Grude

doi:10.1029/2000jb000132

Cited by 62 publications

(60 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The combination of the continuum and discrete constitutes allows solving the first direction of the solid effects on the fluid with the continuum component, and the second direction of the fluid effect on the grain dynamics with the discrete component. Such an approach was used in the modeling of instabilities in the flow of granular media and gas fluids [McNamara et al, 2000, Vinningland et al, 2007a,b, Johnsen et al, 2006, 2008, Vinningland et al, 2010 and liquids of various compressibilities and viscosities [Niebling et al, 2010], for modeling hydrofractures [Flekkøy et al, 2002], and for the study of soil liquefaction [El Shamy andZeghal, 2007, Okada andOchiai, 2007]. Such an approach is adopted in the current work.…”

Section: Overview Of Existing Research Approachesmentioning

confidence: 99%

The Mechanical Coupling of Fluid-Filled Granular Material Under Shear

Goren

Aharonov

Sparks

et al. 2011

Pure Appl. Geophys.

View full text Add to dashboard Cite

Abstract. The coupled mechanics of fluid-filled granular media controls the physics of many Earth systems such as saturated soils, fault gouge, and landslide shear zones. It is well established that when the pore fluid pressure rises, the shear resistance of fluid-filled granular systems decreases, and as a result catastrophic events such as soil liquefaction, earthquakes, and accelerating landslides may be triggered. Alternatively, when the pore pressure drops, the shear resistance of these geosystems increases. Despite the great importance of the coupled mechanics of grains-fluid systems, the basic physics that controls this coupling is far from understood. Fundamental questions that need to be addressed are what are the processes that control pore fluid pressurization and depressurization in response to deformation of the granular skeleton? and how do variations of pore pressure affect the mechanical strength of the grains skeleton? To answer these questions, a formulation for the pore fluid pressure and flow is developed from mass and momentum conservation, and is coupled with a granular dynamics algorithm that solves the grain dynamics, to form a fully coupled model. The pore fluid formulation reveals that the evolution of pore pressure obeys a viscoelastic rheology in response to pore space variations. Elastic-like behavior dominates with undrained conditions and leads to a linear relation between pore pressure and overall volumetric strain. Viscous-like behavior dominates under well drained conditions and leads to a linear relation between pore pressure and volumetric strain rate. Numerical simulations reveal the possibility of liquefaction under drained and initially over-compacted conditions, which were often believed to be resistant to liquefaction. Under such conditions liquefaction occurs during short compactive 1 phases that punctuate the overall dilative trend. In addition, the more established generation of elevated pore pressure under undrained compactive conditions is observed. Simulations also show that during liquefaction events stress chains are detached, the external load becomes completely supported by the pressurized pore fluid, and shear resistance vanishes.

show abstract

Section: Overview Of Existing Research Approachesmentioning

confidence: 99%

The Mechanical Coupling of Fluid-Filled Granular Material Under Shear

Goren

Aharonov

Sparks

et al. 2011

Pure Appl. Geophys.

View full text Add to dashboard Cite

show abstract

“…However, a complete analysis of this phenomenon would imply, in principle, the use of a micromodel in which the generation and propagations of cracks are properly modeled in the computation of the fluid pressure. For example, the effect of pore fluid pressure and fracturation should be explicitly included into the variation of b T (through the dependence of the permeability) and R. A physical model of hydrofracturation has been described very recently [Flekkøy et al, 2002], which could be used for this purpose.…”

Section: Ecvmentioning

confidence: 99%

The volcano‐electric effect

2003

View full text Add to dashboard Cite

[1] The formation of a magmatic intrusion at depth is responsible for the formation of various thermohydromechanical (THM) disturbances including the upsurge of shock waves and diffusion of pressure fronts in the volcanic system. We couple electromagnetic theory (Maxwell equations) and thermoporoelasticity (Biot equations) to look at the ground surface electrical signature of these THM disturbances. The nature of this coupling is electrokinetic, i.e., associated with water flow relative to the mineral framework and the drag of the excess of charge located in the vicinity of the pore water/mineral interface (the groundwater flow disturbance being related here to the THM disturbances in drained conditions). A new set of laboratory data shows that the electrokinetic coupling is very substantial in fractured basaltic and volcaniclastic materials, and in scoria with several hundreds of millivolts of electrical potential gradient produced per megapascal of pore fluid pressure variations. Our theoretical analysis predicts the diffusion of electromagnetic disturbances and quasi-static electrical signals. These signals can be used as precursors of a volcanic eruption. Indeed, electromagnetic phenomena recorded at the ground surface of a volcanic system, once properly filtered to remove external contributions, provide a direct and quasi-instantaneous insight into the THM disturbances occurring in the heart of the volcanic structure prior and during a volcanic event. Tomography of the quasi-static electrical field is discussed and applied to self-potential profiles performed at the Piton de la Fournaise volcano during the preparation phase of the March 1998 eruption.

show abstract

“…The equilibrium configuration is defined by a given 143 relaxation threshold. The net force ( F i ) acting on an element i at position x i is 144 [24]. 160…”

Section: Mechanics 137mentioning

confidence: 99%

Growth of stylolite teeth patterns depending on normal stress and finite compaction

Koehn¹,

Renard²,

Toussaint³

et al. 2007

Earth and Planetary Science Letters

107

115

View full text Add to dashboard Cite

14Stylolites are spectacular rough dissolution surfaces that are found in many rock types. 15They are formed during a slow irreversible deformation in sedimentary rocks and therefore 16 participate to the dissipation of tectonic stresses in the Earth's upper crust. Despite many 17 studies, their genesis is still debated, particularly the time scales of their formation and the 18 relationship between this time and their morphology. 19We developed a new discrete simulation technique to explore the dynamic growth of 20 the stylolite roughness, starting from an initially flat dissolution surface. We demonstrate that 21 the typical steep stylolite teeth geometry can accurately be modelled and reproduce natural 22 patterns. The growth of the roughness takes place in two successive time regimes: i) an initial 23 non-linear increase in roughness amplitude that follows a power-law in time up to ii) a critical 24 time where the roughness amplitude saturates and stays constant. We also find two different 25 spatial scaling regimes. At small spatial scales, surface energy is dominant and the growth of 26 the roughness amplitude follows a power-law in time with an exponent of 0.5 and reaches an 27 early saturation. Conversely, at large spatial scales, elastic energy is dominant and the growth 28 follows a power-law in time with an exponent of 0.8. In this elastic regime, the roughness 29 does not saturate within the given simulation time. 30Our findings show that a stylolite's roughness amplitude only captures a very small 31 part of the actual compaction that a rock experienced. Moreover the memory of the 32 * Manuscript Click here to download Manuscript: Styloteeth_EPSL.doc -2 -compaction history may be lost once the roughness growth saturates. We also show that the 33 stylolite teeth geometry tracks the main compressive stress direction. If we rotate the external 34 main compressive stress direction, the teeth are always tracking the new direction. Finally, we 35 present a model that explains why teeth geometries form and grow non-linearly with time, 36 why they are relatively stable and why their geometry is strongly deterministic while their 37 location is random. 38

show abstract

Modeling hydrofracture

Cited by 62 publications

References 14 publications

The Mechanical Coupling of Fluid-Filled Granular Material Under Shear

The Mechanical Coupling of Fluid-Filled Granular Material Under Shear

The volcano‐electric effect

Growth of stylolite teeth patterns depending on normal stress and finite compaction

Contact Info

Product

Resources

About