Sandia National Laboratories is a federally funded research facility operated by Sandia Corporation for the Department of Energy. The presentation discusses research on fluid flow through rock salt. It summarizes the theory of how pore networks evolve in ductile rocks under pressure and temperature. Laboratory experiments on rock salt samples show that pore connectivity and fluid percolation depend on porosity and dihedral angle as predicted by the theory. Comparison to field data from hydrocarbon wells in salt formations shows generally good agreement between observations and the theoretical model.

1. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia
Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department
of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000..
Capillary controls on brine percolation
in rock salt
Marc Hesse and Maša Prodanović
(Soheil Ghanbarzadeh)
University of Texas at Austin
Washington, DC
September 7-9, 2016

2. Funding and motivation
2
Understand the role of salt permeability in control of sub-salt pressure.

3. Fluid percolation in ductile rocks
3
Glacier ice Planetary interiors Rock salt
Ductile deformation
Accumulation of large and permanent strains without macroscopic
fracturing ⟹ very active microstructure accommodating deformation
Implication of this active microstructure for pore fluid distribution?
NASA Earth ObservatoryIPGP Antoine PitrouGlobal Science

4. Evolution to textural equilibrium
4
Alloys Temperate ice Rock salt
Definition
Pore geometry evolves to minimize the energy of the liquid-solid interfaces,
while maintaining a constant dihedral angle at slid-solid-liquid contact lines.
Partial melts
Smith (1948) Nye & Mae (1972) van Bargen & Waff
(1986)
Lewis & Holness
(1996)

5. Theory of textural equilibrium
5
Mechanical
Equilibrium
Surface energy
minimization
Equilibrated
pore space
Definition
Pore geometry evolves to minimize the energy of the liquid-solid interfaces,
while maintaining a constant dihedral angle at slid-solid-liquid contact lines.
+ =
Pore network controlled by 2 Parameters: dihedral angle q and porosity f

6. Simulated pore networks
Developed a Level-set method for texturally equilibrated pore networks.
Pore network controlled by 2 Parameters: dihedral angle q and porosity f
Regular grains Irregular grains
Ghanbarzadeh, Hesse & Prodanović (2015) J Comp Phys

7. Percolation threshold
Ghanbarzadeh, Hesse & Prodanović (2016) in review for Nat Geosci
q=10°q=7𝟎°q=9𝟎°
f = 2% f = 5% f = 10%
0 155 2010 3025
porosity: f [%]
120
80
60
20
40
100
0
dihedralangle:q[°]
Percolation threshold (real grains
)

8. Percolation threshold
Ghanbarzadeh, Prodanović & Hesse (2014) Phys Rev Lett
Ghanbarzadeh, Hesse & Prodanović (2016) in review for Nat Geosci
0 155 2010 3025
porosity: f [%]
120
80
60
20
40
100
0
dihedralangle:q[°]
Percolation threshold (real grains
)
Ideal grains Real grains
Percol
ation
th
reshold(idealgrains)

9. Testing theory in lab
9
Laboratory experimentsEffect of P & T
Lewis & Holness (1996) Geology Jim Gardner’s lab at UT

10. Test pore-space connectivity
High-Resolution X-ray Computed Tomography
10

11. Low pressure & temperature
11
Dihedral angle 66° porosity 3% ⟹ Pores do not percolate.
Ghanbarzadeh, Hesse & Prodanović (2015) Science

12. High pressure & temperature
12
Ghanbarzadeh, Hesse & Prodanović (2015) Science
Dihedral angle 50° porosity 7% ⟹ Pores do percolate.

13. Comparison with theory
13

14. Limit of low porosity
14

15. Limit of low porosity
15
57
50 150 200
50
100
150
200
P[MPa]
T [°C]
0
1000
55 53 50-2
0
0 200
5355
56
56 55
59
57
61
61
61
62
6266
6063
6671
68
72
Depth[km]
7
4
3
2
1
0
8
6
5
Lewis & Holness (1996)

16. Hydrocarbon exploration wells
16
57
50 150 200
50
100
150
200
P(MPa)
T (°C)
0
1000
55 53 50-2
0
0 200
5355
56
56 55
59
57
61
61
61
62
6266
6063
6671
68
72
depth(km)
7
4
3
2
1
0
8
6
5
Lewis & Holness (1996)
AT1
GC2
GC7
GC8
MC11
WR13

17. Hydrocarbon exploration wells
17
57
50 150 200
50
100
150
200
P(MPa)
T (°C)
0
1000
55 53 50-2
0
0 200
5355
56
56 55
59
57
61
61
61
62
6266
6063
6671
68
72
depth(km)
7
4
3
2
1
0
8
6
5
Lewis & Holness (1996)

18. Well and mud logs
0 25(API)
G-Ray
102 105(ohm.m)
Resistivity
1 103(unit)
Gas HC Max
1 106(ppm)
Gas Chromatography
(m)
55 75(°)
θ
Fluoresce
Oil Stain
Dead Oil
Oil Cut
2200
2700
3200
3700
4200
4700
5200
5700
6200
Mud Log
CH4
C2H6
C3H8
C4H10
C5H12
18
Ghanbarzadeh, Hesse & Prodanović (2015) Science

19. Well and mud logs
0 25(API)
G-Ray
102 105(ohm.m)
Resistivity
1 103(unit)
Gas HC Max
1 106(ppm)
Gas Chromatography
(m)
55 75(°)
θ
Fluoresce
Oil Stain
Dead Oil
Oil Cut
2200
2700
3200
3700
4200
4700
5200
5700
6200
Mud Log
CH4
C2H6
C3H8
C4H10
C5H12
19Good agreement between field data and theoretical prediction

20. Comparison for 150km’s of salt
1 2 3 4 5 96 87 10 1412 1311
AT MCGC KC WR
(°)estimated
70
65
55
60
Fluoresce
Oil Stain
Dead Oil
Oil Cut
Salt Extent
20

21. Effect of deformation?
21
Bruhn et al. (2000)
Nature
Partially molten rocks
Schenk & Urai (2005)
J Metamorphic Geol
Deformation in rock salt

22. Are conditions relevant?
22
Gorleben P&T conditions
(Eickemeier et al. 2013)

23. Are conditions relevant?
23
Motivation for Lewis & Holness (1996)

24. Are conditions relevant?
24

25. Large porosities in experiments
25
f = 0.5% f = 1.0% f = 3.0%
Both theory and simulations suggest percolation at
very low porosities for dihedral angles below 60 degrees.
Ghanbarzadeh, Prodanović & Hesse (2014) Phys Rev Lett

26. Was oil deposited with salt?
26