A3 Léa Lévy Electrical conduction of low-salinity hydrothermal systems: a quantitative measure of...
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Léa Lévy - GEORG conference 1
ELECTRICAL CONDUCTION: A QUANTITATIVE MEASURE OF THE
SMECTITE AND CHLORITE CONTENT?STUDY BASED ON CORES FROM KRAFLA
24.11.2016
LÉA LÉVYIN COLLABORATION WITH:
ÓLAFUR G. FLÓVENZGYLFI PÁLL HERSIR
FREYSTEINN SIGMUNDSSONBENOIT GIBERT
AND MANY MORE
Léa Lévy - GEORG conference 2
What is clay?
• CEC = Cation Exchange Capacity• Between T sheets „Internal exchange“
• Only in smectite• On the edges „External exchange“
• Minimal compared to internal• Unit = meq/100g or C/kg• Measured by chemical titration
24.11.2016
Chlorite
Illite
Smectite
• Phyllosilicates• T = tetrahedral sheet (Si)• O = octahedral sheet (Al or Mg)• Sequences T-O-T
• Substitutions Negative charge• Compensation between sheets
From multiple sources. Ex: Lyklema, 2001
Léa Lévy - GEORG conference 3
Charge and mobility
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Internal CEC (meq/100g)
100
Smectites Illite Chlorite
# water layers
0
1
2
|Total charge|0 0.70.50.3 10.9 2
T-O No charge
T-O-T low charge
T-O-T high charge
higher charge stronger bondings structure more stableStability
Brucitic layer
Cation with 2 water shellsNothing Cations with 1 water shell Cations with 0 water shell
Weak Coulombian attraction Van der Waals bondings of increasing strength H bondings
Montmorillonite 2 water shells
From Meunier, 2000
Beidellite 1 water shell
Léa Lévy - GEORG conference 4
The smectite chlorite transition
• Kinetic vs thermodynamics• Intermediary step
• Hydrothermal convection vs heat conduction
• Presence/absence of smectite
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„Smectite is a kinetic step in the formation of chlorite by hydrothermal convection.“
Electrical conduction
Chlorite
precipitation
Unstable smectite
Weak bondings
Hydrothermal convection
Low charge
Léa Lévy - GEORG conference 5
Context of the study
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(b)
KH-5 (a) 288m – Epidote, quartz, wairakite. (b) 279 m – Epidote overprinted by laumontite.
(c) (d)
KH6. 594 m – Zeolite transforming into wairakite.
(b)
KH-3 – 273 m. Precipitation of MLC and chlorite in vesicles.
KH-1. 74 m – Stilbite and smectite.
Map by Þorbergsson and Víkingsson, 2016
Léa Lévy - GEORG conference 6
Clay content and CEC
24.11.20160% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50%0
5
10
15
20
25
30
35
40
45
50CEC and clay fraction of whole rock samples
Based on XRD {d(001) + d(002)}
Clay fraction (XRD)
CEC
meq
/100
g
Léa Lévy - GEORG conference 7
Clay content and CEC
24.11.2016
0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50%0
5
10
15
20
25
30
35
40
45
50
f(x) = 85.6732646863277 xR² = 0.998964852312329
f(x) = 109.554255319498 xR² = 0.992382803702646
CEC and clay fraction of whole rock samplesBased on XRD {d(001) + d(002)}100% smectite
Linear (100% smectite)75% smectite
Clay fraction (XRD)
CEC
meq
/100
g
𝐶𝐸𝐶0=110meq /100 g
Léa Lévy - GEORG conference 8
Clay content and CEC
24.11.20160% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50%0
5
10
15
20
25
30
35
40
45
50
f(x) = 67.3605198067388 xR² = 0.995675531585296
f(x) = 85.6732646863277 xR² = 0.998964852312329
f(x) = 109.554255319498 xR² = 0.992382803702646
CEC and clay fraction of whole rock samplesBased on XRD {d(001) + d(002)}100% smectite
Linear (100% smectite)75% smectiteLinear (75% smectite)
Clay fraction (XRD)
CEC
meq
/100
g
𝐶𝐸𝐶0=110meq /100 g
Léa Lévy - GEORG conference 9
Clay content and CEC
24.11.20160% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50%0
5
10
15
20
25
30
35
40
45
50
f(x) = 22.9271506126017 xR² = 0.991618970236235
f(x) = NaN xR² = 0f(x) = NaN xR² = 0f(x) = NaN xR² = 0f(x) = NaN xR² = 0 CEC and clay fraction of whole rock samples
Based on XRD {d(001) + d(002)}100% smectiteLinear (100% smectite)75% smectiteLinear (75% smectite)60% smectiteLinear (60% smectite)40% smectite
Clay fraction (XRD)
CEC
meq
/100
g
𝐶𝐸𝐶0=110meq /100 g
Léa Lévy - GEORG conference 10
Clay content and CEC
24.11.20160% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50%0
5
10
15
20
25
30
35
40
45
50
f(x) = 11.4645347289964 xR² = 0.906321037448669
f(x) = 22.9271506126017 xR² = 0.991618970236235
f(x) = NaN xR² = 0f(x) = NaN xR² = 0f(x) = NaN xR² = 0f(x) = NaN xR² = 0 CEC and clay fraction of whole rock samples
Based on XRD {d(001) + d(002)}100% smectiteLinear (100% smectite)75% smectiteLinear (75% smectite)60% smectiteLinear (60% smectite)40% smectite
Clay fraction (XRD)
CEC
meq
/100
g
𝐶𝐸𝐶0=110meq /100 g
Conductivity and CEC
24.11.2016 Léa Lévy - GEORG conference 11
𝜎 𝑏𝑢𝑙𝑘=𝜎𝑤
𝐹 +𝜎𝑠
1% 10% 100%10
100
1,000f(x) = 3.7495642436383 x^-1.88521828150962R² = 0.758377622899604
Formation factor and porosity
Porosity
Form
ation
fact
or
0.01 0.1 1 101E-03
1E-02
1E-01
1E+00Bulk conductivity vs fluid conductivity
Fluid conductivity (S/m)
Bulk
con
ducti
vity
(S/m
)
𝑚=1.89
1/F𝜎 𝑠
0 1 10 1001E-04
1E-03
1E-02
1E-01
1E+00
R² = 0.637033931540875
R² = 0.888254949986008
Interface conductivity vs CEC
Cs*F*PorPower (Cs*F*Por)
CEC (meq/100g)
Cond
uctiv
ity (S
/m)
m Rock type Published in
1.33 Seafloor MAR Pezard, 19901.74-2.43 Shaly sands Waxman & Smits, 1968
2.45 Hawaiian basalt Revil et al., 20162.75 Icelandic basalt Flóvenz et al., 2005
Fluid conductivity
Formation factor
Clay „Interface“ conductivity
𝜎 𝑠=f (CEC , F ,∅ )
𝐹=a∅−𝑚
Porosity
(Waxman & Smits, 1968)
(Archie, 1942)
Contribution of claySmall
Moderate High
12
Conductivity and smectite
24.11.2016 Léa Lévy - GEORG conference
𝜎 𝑠∗F ∗∅= f (CEC )=f (smec%)
1% 10% 100%1E-03
1E-02
1E-01
1E+00
Normalized interface conductivity vs clay%
Clay >50% smectiteClay 20-50% smectiteClay < 20% smectite
Clay fraction in the whole rock (XRD)
Whole rock < 2% smectiteBetween 7 and 20% of clay 5 to 18% chlorite in whole rock
0% 1% 10% 100%1E-03
1E-02
1E-01
1E+00
R² = 0.912397564063714
Normalized interface conductivity vs smectite%
Meaningful smectite content (> 1 %)Power (Meaningful smectite content (> 1 %))
Smectite fraction in the whole rock (CEC)
Cond
uctiv
ity (S
/m)
𝑤𝑡% (𝑠𝑚𝑒𝑐)=𝐶𝐸𝐶𝐶𝐸𝐶0
𝐶𝐸𝐶0=110meq /100 g
Léa Lévy - GEORG conference 13
Conclusions• Electrical conductivity measures the smectite content
• At low-salinity• Normalized by F*φ• Independent of chlorite content
• Weak bondings in smectite are a key in geothermal exploration• Smectite content is a measure of hydrothermal activity (unstability)• Smectite content can be measured by electrical conduction (CEC)
Could we use the evolution of the smectite content to locate the transition between heat convection
and heat conduction?24.11.2016
Léa Lévy - GEORG conference 14
Thank you !OTHER SCIENTISTS I WOULD LIKE TO ACKNOWLEDGE INCLUDE
PHILIPPE PEZARDPIERRE BRIOLE
SIGURÐUR SVEINN JÓNSSONÞRÁINN FRIÐRIKSSON
HELGA M. HELGADÓTTIRHJALTI FRANZSON
ANDRÉ REVILALAIN MEUNIER
PHILIPPE COSENZA
24.11.2016
Léa Lévy - GEORG conference 15
Appendix
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Léa Lévy - GEORG conference 16
Complex conductivity
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𝜎 𝑏𝑢𝑙𝑘∗ =𝜎 ′+𝑖𝜎 ′ ′
Carry an electrical current Stores electrical charges𝜎 ′= f (𝜎𝑤 ,CEC , F ,∅ )
(
1E+02 1E+03 1E+04 1E+051E-03
1E-02
1E-01
1E+00
f(x) = 0.00051061239042286 x^0.456852491142259R² = 0.544357484627649
Correlation of quadrature conductivity (using dif -ferent correction factors) and CEC
C''*F 10 Hz Cw=1,5 S/m
CEC (C/kg)
Qua
drat
ure
Cond
uctiv
ity (S
/m)
Léa Lévy - GEORG conference 17
Comparison between borehole conductivity (from the 64'' resistivity log) and CEC from cuttings in borehole KJ-18
Conductivity and CEC in borehole KJ-18
CEC (cuttings) and conductivity (borehole log)
24.11.2016
Léa Lévy - GEORG conference 18
Thermodynamics of cation exchange
0 100 200 300 400 500 600 700 8000
5
10
15
20
25
30
35
40
Variation of apparent CEC with rock massInitial concentration of Cu-trien varies between 1.52x10-3 and 1.73x10-3 mol/L
L81L82L96L40L31L22L16L14L11L09L06L99
mass of rock / initial concentration in mg/(mol/L)
CEC
appa
rent
(meq
/100
g)
24.11.2016
Léa Lévy - GEORG conference 19
0 50 100 150 2000
5
10
15
20
25
30
L22 - CEC and K DeterminationK = 100
CEC = 24,2
(e)
0 20 40 60 80 100120140 1601802000
5
10
15
20
25
30
35
40
L14 - CEC and K DeterminationK = 20
CEC = 38
Cu(t
rien)
cons
umed
by
the
reac
tion
in m
eq/1
00g
05
10152025303540
L09 - CEC and K DeterminationK = 25
CEC = 37
0 20 40 60 80 100 120 140 160 180 2000
5
10
15
20
25
30
35
L06 - CEC and K DeterminationK = 20
CEC = 32.8
2VCi/m = Initial Cu(trien) content in meq/100g
Cu(t
rien)
con
sum
ed b
y th
e re
actio
n in
m
eq/1
00g
0 40 80120
160200
05
10152025303540
L99 - CEC and K DeterminationK = 30
CEC = 34
2VCi/m = Initial Cu(trien) content in meq/100g
(a)
(c)
(d)
(b)
0 20 40 60 80 1001201401601802000
5
10
15
20
25
L11 - CEC and K DeterminationK = 50 or 25
CEC = 23,2 or 21,8
2VCi/m = Initial Cu(trien) content in meq/100g
(f)
Analytical fit of experimental observations
24.11.2016
Léa Lévy - GEORG conference 20
Normalization of interface conductivity
24.11.2016
0 1 10 1001E-04
1E-03
1E-02
1E-01
1E+00
1E+01
R² = 0.637033931540875
R² = 0.888254949986008
R² = 0.845168057471815
Interface conductivity vs CEC
Cs*FPower (Cs*F)
CEC (meq/100g)
Cond
uctiv
ity (S
/m)
Léa Lévy - GEORG conference 21
References• Flóvenz, Ó. G., Spangenberg, E., Kulenkampff, J., Árnason, K., Karlsdóttir, R. and Huenges, E. (2005). The role of
electrical interface conduction in geothermal exploration. World Geothermal Congress, Ankara, Turkey, 2005.• Lyklema, J. (2001). Fundamentals of Interface and Colloid Science. Volume II Solid-Liquid Interfaces. Academic
Press.• Meier, L. and Kahr, G. (1999). Determination of the Cation Exchange Capacity (CEC) of Clay Minerals Using the
Complexes of Copper(II) Ion with Triethylenetetramine and Tetraethylenepentamine. Clays and Clay Minerals 47(3), 386–388.
• Meunier, A. (2013). Les argiles par la pratique. Vuibert• Pezard, P. A. (1990). Electrical properties of mid-ocean ridge basalt and implications for the structure of the
upper oceanic crust in Hole 504B. Journal of Geophysical Research 95(B6), 9237.• Vinegar, H. J. and Waxman, M.H. (1984). Induced polarization of shaly sands. Geophysics 49(8), 1267–1287.• Revil, A., Le Breton, M., Niu, Q., Wallin, E., Haskins, E. and Thomas, D.M. (2016). Induced polarization of
volcanic rocks. I. Surface versus quadrature conductivity. In press.• Waxman, M. H. and L. J. M. Smits (1968). Electrical conductivities in oil-bearing shaly sands. Soc. Pet. Eng. J. 8,
107–122.
24.11.2016
Léa Lévy - GEORG conference 22
Clay content and CEC
24.11.2016
0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50%0
5
10
15
20
25
30
35
40
45
50
f(x) = 9.20391697567538 xR² = 0.76237034371547
f(x) = 36.0222172472408 xR² = 0.944495433329317
f(x) = 67.8609886672848 xR² = 0.994174302124352
f(x) = 92.2302711736049 xR² = 0.982512087330206
CEC and clay fraction – based on the sum of d(001) and d(002) areas – of whole rock samples
Clay >90% SmectiteLinear (Clay >90% Smectite)MLC with 50-90% smectiteLinear (MLC with 50-90% smectite)MLC with 20-50% smectite
Clay fraction (assuming the highest has 50% of clay)
CEC
meq
/100
g
𝐶𝐸𝐶0=110meq /100 g