Transcript Multiphase eld-scale modeling

Multiphase Field-scale
Modeling: Brine Transport
Ann Cook
Per Hatlevik
Jonathan Levine
Brice Loose
Keegan Roberts
Amber Sallerson
Katy Schulte
Martina Vlckova
Thomas Willingham
Introduction to DNAPLs
• Types
• Sources
• Behavior
 na
hc 
(n  a ) g
PCE, TCE, DCE,
VC, CT, CF, DCM,
TCA
Introduction to DNAPLs
• Long lived
• Difficult to remove
• Health Hazards
Density of
Water (rw)
~1 g/mL
Density of
DNAPL (rn)
~1.45-1.62 g/mL
– Liver problems
– Increased risk of cancer
– Nervous system, or circulatory problems1
Brine Treatment Technology
• How does it work?
– Mobilization of the NAPL
• Increase Gravimetric Forces
• Decrease Capillary Trapping Forces
Brine Treatment Technology
 na
r
•
•
•
•
•
•
sn-a
r
rn
ra
g
l
=
=
=
=
=
=
 (  n   a ) gl
NAPL-aqueous interfacial tension
effective pore size
NAPL density
aqueous phase density
gravitational acceleration
characteristic length of NAPL
pool in vertical direction
Brine Treatment Technology
• How does it work?
– Closed system on 5 sides
Area of Remediation
Sheet-piles
Impermeable Layer (e.g., clay)
Plan View
Profile View
Brine Treatment Technology
• How does it work?
No Flow
Boundary
No Flow
Boundary
Brine Treatment Technology
• How does it work?
Pump in
Brine Layer
Brine Treatment Technology
• How does it work?
Lower
Water Table
Brine Treatment Technology
• Gravimetric Forces
Removal
of
DNAPL
Brine Treatment Technology
• How does it work?
Brine Treatment Technology
• How does it work?
Removal
of
DNAPL
Brine Treatment Technology
• How does it work?
Brine Treatment Technology
• How does it work?
Remove
Brine
<1% Original
DNAPL Mass
Brine Treatment Technology
• How does it work?
<1% Original = Meet
DNAPL Mass Standards
Brine Treatment Technology
• Why is it novel?
– $$ Cheaper $$
– Higher rates of removal than current
technologies
Pump and Treat
Natural Attenuation
Possible Instabilities in the System
• Physical
– Density (changes and/or differences)
– Excessive Surfactant Concentration bypass
– Pore Clogging
• Model
– Fingering
– Gravity - Rayleigh
Rayleigh-Taylor Instability
Brine
• Initial density stratified domain
• Unstable system (small
perturbations)
• Occur in model and physical
system
Ground
Water
Rayleigh Number
• Dimensionless Number
• Ratio
buoyancy
Ra 
gravitation
diffusion
dispersion
Modified Rayleigh Number
UcH
Ra 
DT
Ra
Ra * 
 1250
1  Pe *
Vamb L
Pe* 
D0  Vamb L
SUTRA
• Code written by USGS
• Simulates single phase fluid flow and
transport in the subsurface
• Uses a combination of finite-element
and finite difference methods to solve a
series of equations
Conservation Equations
• Species Balance Equation
• Species-Summed Flow Equation
SUTRA Transport
Math Magic
SUTRA Fluid Flow
Species
Summed
Flow Equation
Darcy’s Law
Math Magic
Requirements for SUTRA
DL < 4aL
Pe < 2
• DL = local distance between sides of an element
measured in the direction parallel to local flow
• aL = longitudinal dispersivity
SUTRA Goal
• To model a freshwater system where we
inject brine
– 3D model
– Relatively small in the y-direction
• Visualize system instabilities
• Removal of brine from system
Simulations Ran
1. Brine slumping model
2. Fully saturated fresh water system with
brine injection
3. Unsaturated brine injection
4. Multiple well configurations
Example Problem: Slumping brine interface
High frequency spatial hydraulic conductivity
which admits an analytic solution in the case that the vertical scale is
much less that the horizontal (H << R), and a constant hydraulic
conductivity (Kc)
Homogenization permits approximation of K(x,z,t) as a constant
that captures the variability
Homogenized equations compare well with the accepted
numerical solution. High frequency variations are absent.
Evaluate Instabilities
Injection Wells
Extraction Well
Fingering
k dh
q
 dl
Fingering due
to viscous
instability
brine  water
qbrine  qwater
SUTRA MODELING
BCs
SUTRA MODELING
Initial Injection
SUTRA MODELING
Brine Injection
Transport and Flow Equations
AKA “The Magic”