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Asymptotic regimes in unstable miscible displacements in random porous media
We study two asymptotic regimes of unstable miscible displacements in porous media, in the two limits, where a permeability-modified aspect ratio, R L = L/ H( k v/ k h) 1/2, becomes large or small, respectively. The first limit is known as transverse (or vertical) equilibrium, the second leads to th...
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Published in: | Advances in water resources 2002-08, Vol.25 (8), p.885-898 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | We study two asymptotic regimes of unstable miscible displacements in porous media, in the two limits, where a permeability-modified aspect ratio,
R
L
=
L/
H(
k
v/
k
h)
1/2, becomes large or small, respectively. The first limit is known as transverse (or vertical) equilibrium, the second leads to the problem of non-communicating layers (the Dykstra–Parsons problem). In either case, the problem reduces to the solution of a single integro-differential equation. Although at opposite limits of the parameter
R
L
, the two regimes coincide in the case of equal viscosities,
M=1. By comparison with high-resolution simulation we investigate the validity of these two approximations. The evolution of transverse averages, particularly under viscous fingering conditions, depends on
R
L
. We investigate the development of a model to describe viscous fingering in weakly heterogeneous porous media under transverse equilibrium conditions, and compare with the various existing empirical models (such as the Koval, Todd–Longstaff and Fayers models). |
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ISSN: | 0309-1708 1872-9657 |
DOI: | 10.1016/S0309-1708(02)00043-X |