Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Viscous fingering in fractured porous media   The effect of heterogeneities induced by highly permeable fracture networks
on viscous miscible fingering in porous media is examined using high-resolution
numerical simulations. We consider the planar injection of a less viscous fluid
into a two-dimensional fractured porous medium which is saturated with a more
viscous fluid. This problem contains two sets of fundamentally different
preferential flow regimes; the first is caused by the viscous fingering and the
second is due to the permeability contrasts between the fractures and rock
matrix. We study the transition from a regime where the flow is dominated by
the viscous instabilities, to a regime where the heterogeneities induced by the
fractures define the flow paths. We find that fractures greatly affect the
viscous fingering, even for small permeability differences between the rock
matrix and the fractures. The interaction between the viscosity contrast and
permeability contrast causes channeling of the less viscous fluid through the
fractures and back to the rock. This channeling stabilizes the displacement
front in the rock matrix, and the viscous fingering ceases for the higher
permeability contrast. Several different fracture geometries are considered,
and we observe a complex interplay between the geometries and unstable flow.
While we find that the most important dimensionless number determining the
effect of the fracture network is a weighted ratio of the permeability of the
fractures and the permeability of the rock matrix, the exact point for the
cross-over regime is highly dependent on the geometry of the fracture network.

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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: cs
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The categories of this paper are: chem-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: stat
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: hep-th
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The categories of this paper are: q-alg
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The categories of this paper are: hep-ex