Numerical simulations of oil contaminant transport in sandy coastal aquifers
Presenter: Yi-Ming Wei
Adviser: Chuen-Fa Ni
Date: 2011/04/21
Outline
Motivation Objectives Methodology Test example Future work
Motivation
With the increasing developments of tourist and industrial
estates in coastal area, different sources of contaminants
can be discharged into the sea.
Marine pollution : Oil spills happen when people make
mistakes or are careless and cause an oil tanker to leak
oil into the ocean.
彭薩科拉海灘 ( Pensacola)
Objectives
when a petroleum spill reaches the beaches, there may be
deeper penetration in the soil, which depends on sand grain
size, so causing serious damages to the ecosystem.
(1) how much and how deep oil is transported into the beaches.
(2) Whether oil polluted groundwater or not.
(3) Other factor of influence oil transportation : tidal 、 wave 、
beach slope 、 pumping well 、 recharge water …
Methodology-HYDROGEOCHEM-2D
A coupled model of fluid flow, thermal transport, and
HYDROGEOCHEMical transport through saturated-
unsaturated media.
Deal with equilibrium and kinetic reaction in terms
of reaction networks.
Incorporate the effect of precipitation /dissolution
on the change of pore size, hydraulic conductivity,
and diffusion/dispersion.
Flow Equations
0 0 0
ee
00
s r
00
hF K ( h+ z) q
t
dSF n
n dh
gg
K k k k
1F is storage coefficient
L
1q is the source/sink
T
3
M is fluid density with dissolved chemical concentrations
L
0 3
M reference fluid density at zero chemical concentration
L
3
M is the density of the injected fluid
L
is effective moisture content1
is the modified compressibility of the soil matrixL
1
is modified compressibility of the liquidL
2sk is saturated permeability tensor L
rk is relative permeability or relative hydraulic conductivity
2 is degree of effective saturation of water LS
Reactive Chemical Transport Equations
ii f j j i
C( C V ) J r M
t
The rate of mass accumulation
The net rate of mass flux due to advection
The net mass flux due to dispersion and diffusion,
The rate of mass production and reduction due to chemical reactions and radioactive decay
The source/sink term corresponding to artificial injection and/or withdrawal
iC
t
i f( C V )
jJ
jr
iM
j i T L T mJ C a V (a a )VV / V aD
Test example
Pressure head= 85m
400 m
100 m
Pressure head= 84m
Impermeable bottom
Variable boundary condition
15 /K m day porosity of the aquifer = 0.35
Slope
Pressure head= 85m
400 m
100 m
Pressure head= 84m
Impermeable bottom
Beach slope = 0.2、 0.3
No rainfall
1.0 mole/liter ( C6H6)
x (m)
z(m)
0 100 200 300 4000
50
1008685.885.685.485.28584.884.684.484.2
0 100 200 300 4000
50
100
Beach slope = 0.2
Beach slope = 0.3
Total head
x (m)
z(m
)
0 100 200 300 4000
50
100 8685.885.685.485.28584.884.684.484.2
0 100 200 300 4000
50
100
x (m)
z(m
)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
Beach slope = 0.2
Beach slope = 0.3
12day
x (m)
z(m
)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
Beach slope = 0.2
Beach slope = 0.3
27day
x (m)
z(m
)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
x (m)
z(m
)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
Beach slope = 0.2
Beach slope = 0.3
46day
x (m)
z(m
)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
x (m)
z(m
)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
I = 0.01 m/day
Recharge
Pressure head= 85m
400 m
100 m
Impermeable bottom
Pressure head= 84m
Beach slope = 0.2
1.0 mole/liter ( C6H6)
x (m)
z(m)
0 100 200 300 4000
50
1008685.885.685.485.28584.884.684.484.2
0 100 200 300 4000
50
100
Total head
No rainfall
x (m)
z(m)
0 100 200 300 4000
50
1008685.885.685.485.28584.884.684.484.2
0 100 200 300 4000
50
100
I = 0.01 m/day
27day
x (m)
z(m
)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
No rainfall
I = 0.01 m/day
x (m)
z(m)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
Pumping well
Pressure head= 85m
400 m
100 m
Impermeable bottom
Beach slope = 0.2
No rainfall
1.0 mole/liter ( C6H6)
Pressure head= 84m
-20 m2/day(抽水 )
Total head
x (m)
z(m)
0 100 200 300 4000
50
1008685.885.685.485.28584.884.684.484.2
0 100 200 300 4000
50
100
no pumping well
pumping well
x (m)
z(m)
0 100 200 300 4000
50
100
8685.885.685.485.28584.884.684.484.28483.883.683.483.283
0 100 200 300 4000
50
100
27day
x (m)
z(m
)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
pumping well
no pumping well
x (m)
z(m
)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
46day
pumping well
no pumping well
x (m)
z(m
)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
x (m)
z(m
)
0 100 200 300 4000
50
100
0.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.05
Future work
Thanks for your attention