Description of the following porous medium
A) poorly sorted sedimentary deposit with high porosity
B) well sorted sedimentary deposit having low porosity
C) poorly sorted sedimentary deposit consisting of pebbles that are themselves porous
D) very well sorted sedimentary porosity with very low porosity
E) rock made porous by dissolution
F) fractured rock
Def.: REV
Representative Elementary Volume: A portion of space occupied by a number of phases, a least one of which is a solid.
—> correlated to continuum approach
(from microscopic level to macroscopic level: for example velocity at one point to average velocity in REV)
Aquifer vs. Aquiclude
Aquifer:
contains full saturation
permits water to move through it
Aquiclude:
may contain water
is incapable of transmitting
Types of aquifer
unconfined
confined
artesian
bounded from above by a phreatic surface and zero pressure
bounded from above by impervious formations
like confined but water level higher than surface
Aquifer vs Reservoir
Aquifer: range 0-1000m depth
Reservoir: depth larger thn 1000m
Darcys law
seepage velocity
Reynolds number
—> for Darcys law Re must not exceed value between 1 and 10
hydraulic conductivity
with
roh * g = specific weight
my = viscosity
k: (given in darcy 1 darcy = 9,87 x 10-9 cm^2)
C = constant
d = grain diameter
Darcy’s law: limits
one dimensional flow
homogenous isotropic porous medium
constant density fluid
non-deformable solid matrix
flow at low Reynolds numbers
saturated flow
averaged momentum balnce equation
Darcy’s law is simplified form.
Averaged momentum balance equation can be generalized to:
Three-dimensional flow
Anisotropic porous media
Inhomogeneous porous media
Fluids of variable density
Unsaturated flow
Principal directions of anisotropic medium
always possible to choose three muttual orthogonal direction that this is valid:
continuity equation
principle of mass conservation
with all our assumptions
Specific storage
volume of water released by a unit volume of porous media for a unit pressure change
porosity
water content
saturation
suction
wettability
wetting phase —> water
non-wetting phase —> air (gas)
molecules of the
Last changed2 years ago