Shale eera fleury

Renewable energies | Eco-friendly production | Innovative transport | Eco-efficient processes | Sustainable resources
Characterization of shales
with low field NMR.
M. Fleury
Energies nouvelles, Rueil-Malmaison, France SCA symposium, 8-11 September 2014, Avignon, France

Energies nouvelles, Rueil-Malmaison, France
Low permeability media and nanoporous
materials
From characterisation to modelling:
can we do it better?
Rueil-Malmaison, France, 9-11 June 2015
2
http://www.rs-lowperm2015.com/
End of Call For Papers: 28 Nov. 2014
LowPerm2015: platform for exchange and interaction between research and
industry players from a variety of different disciplines such as geological
formations (shale, tight sandstone or carbonates, etc.), concrete engineering,
polymer sheaths for pipelines, nanofiltration for produced water treatment,
heterogeneous catalysis, etc.
These very different applications all face the same challenges: the
characterisation and modelling of these media and materials and the
associated transport mechanisms at different scales and potentially enhanced
by the confinement.

Characterization issues
 Pore sizes down to 1 nanometer
 Medium to low porosity (5-15%)
 Presence of organic matter and associated
porosity
 Liquid permeability down to 1nD, gas flow
dominated by Klinkenberg effect
 Simple measurements such as porosity or
cementation exponent m difficult
M. Fleury et al., Caprock and gas shale characterization: appropriate 3 petrophyscial methods

NMR issues
 Does NMR measure total porosity ?
Typical relaxation time of nanopores ?
 Does T2 distribution indicate pore size
distribution ?
Pore coupling effect
 Fluid typing
Methane signature: adsorbed / free gas
Organic matter signature
T2 distribution alone insufficient
 2 approaches:
Use diffusion contrast: T2-D maps
Use T1-T2 contrast: T1-T2 map
4

5
NMR logging examples: caprock
Callovo-Oxfordian formation
Ketzin caprock

6
NMR logging examples: gas shales
Ramirez et al., 2011, SPE144062

NMR conventionnal approach
M. Fleury, Characterization of shales 7 with low field NMR

Fluid typing ?
From Glorioso et al. SPE 167785, 2014
Advanced techniques needed !
NMR signal

Outline
 Relaxation of water in nanopores
 Diffusion properties (cementation exponent
m)
 Relaxation of methane in porous media
 Relaxation of solid or pseudo-solid
components
 Conclusion: fluid typing from T1-T2 map
9

10
102
101
100
10-1
10-2
10-3
10-4
Fast diffusion limit 4r2V/S << D
r2=10 mm/s
r2=1 mm/s
10-1 100 101 102 103 104
Pore size V/S (micron)
Measured T2 (ms)
T2b
Relaxation in nanopores
S
1 = r ´ + 1
T 2
V T Bulk
2
2
1 nm pore sizes
between
0.1 and 1ms

11
Example: caprock sample (COx)
T2 (ms)
(ms)
T
1
101
100
10-1
10-2
Hydroxyls
1
12
2
Mobile water
10-2 10-1 100 101
(23 MHz NMR instrument
18 mm probe)

Study of nanopores in clays
Energies nouvelles, Rueil-Malmaison, France M. Fleury et al., Characterization of interlayer water in clays using low field relaxation and nutation 12 experiments
from Porion et al. J. Phys. Chem. 2007
interlayer spacing
<1nm
Cristal with
hydroxyls
Counter-ions
and water
d001
(SAXS)

13
Example: smectite powder at RH=50%
101
T2 below 0.1 ms should not
be included in porosity
T1 (ms) 10-2 10-1 100 101
T2 (ms)
100
10-1
T1/T2=1
2.5
10
Hydroxyls
Mobile water
Mobile water
(23 MHz NMR instrument
10 mm probe)
Fleury et al., J. Phys. Chem. 2013

T2 in nanopores (smectite powders)

Results: gas shale sample at Sw=1

Measurement of cementation m
 Tortuosity from
resistivity (Archie)
diffusivity
16
= Fm-1
eff
D
m
D
m
R0 = F
w R
Classical method
Need knowledge of
water salinity
From NMR diffusion
Experiments at Sw=1
No specific knowledge
Some potential issues related to
clay conductivity

17
NMR method: deuterium diffusion
Example: Kw=50 nD, f: 6.4 %, size: D=L=15mm
100
80
60
40
20
0
t=0
2.6 hr
H2 outside
sample
10-2 10-1 100 101 102 103
T2 (ms)
A(T2) (a.u.)
16 hr
H2 not exchanged with D2
D2O
ö
æ
C C
* 6 1 exp
= -
2 2
k D t
H2O saturated
sample at t=0
å¥
=
-
f
0 5 10 15 20
0.8
0.6
0.4
0.2
0
-0.2
Time (hr)
C*
Dp=2.48e-006 cm2/s
Diffusion coefficient
m=1.87
÷ ÷
ø
ç ç
è
-
=
1
2
2 2
k
p
i f
r
C C k
C
p
p
Fleury et al., Energy Procedia 2009
Berne et al. , OGST, 2009

Example: gas shale samples
18
0.12
0.1
0.08
0.06
0.04
0.02
0
0 0.02 0.04 0.06 0.08 0.1 0.12
Porosity
Deff/Dm
m=2
m=2.5
RM9-14 D=0.62 10-10 m2/s
2 nD
0 20 40 60 80 100 120 140 160 180
1.2
1
0.8
0.6
0.4
0.2
0
-0.2
Time (hr)
(C-Ci)/(Cf-Ci)
RM3-14 D=1.1 10-10 m2/s
The less porous sample has the highest Deff !!
Measurements
Results
100% water saturated
0.12 nD
m=2.45, 2 nD
m=1.9, 0.12 nD

Water diffusivity: consequences
 Diffusion length much larger than pore size :
D~ 10-10 m2/s, LD=(6Dt)1/2 ~800 nm at t=1ms
Pore sizes <500 nm are in a pore coupling
regime
19
MICP
Difficult to reconcile MICP and NMR !!

Relaxation of methane in porous media
 Fundamental mechanisms known
 Bulk properties (Oosting et al. 1971): spin rotation
 Riehl et al. 1972, NMR relaxation of adsorbed
methane: anisotropic rotationnal motions at the
solid surface
 large T1/T2 ratio
 Existing work in petroleum sciences
 Straley, 1997 T1/T2 ratio >> 1 even in partially
saturated samples
 Recent work: Kausik et al. 2011, Rylander et al.
2013, Tinni et al. 2014….
20

Results for methane
Bulk CH4
200 bar
CH4 in
Shale
Sand

Results for methane in organic matter
100 bar 200 bar

Relaxation of solids or pseudo-solid
components
BPP theory
23
ù
úû
C t
1 2 é
2
t
= 2 2 2 2
1 1 4
êë
+
+
+
8
1
w t
w t
T
ù
úû
C t t
1 é
6 10
t
= + 2 2 2 2
2 1 4
êë
+
+
+
4
1
w t
w t
T
Liquids
Example:
Ice: T2=0.008 ms
T1=70 s at 30 MHz

Amplitude (a.u.)
Détection and quantification of hydroxyls
300
250
200
150
100
50
0
-50
Smectite 200°C
Cristal with
hydroxyls
Water
(removed
at 200°C)
10-2 10-1 100
Time (ms)
86% hydroxyls compared to XRD formulae:

Detection of organic matter in coal
British coal
Anthracite
Vitrinite reflectance: 2.41
Specific density: 1.35
German coal
High volatile bituminous
Vitrinite reflectance: 0.79
Specific density: 1.71

Results: organic matter from shales (1/2)
Immature Oil window Gas window
Hydrogen content:
59 mg/g 30 mg/g 21 mg/g

Results: organic matter in shales (2/2)
« Dry » samples
Oil window Gas window
?

Principle of T1-T2 maps
103
102
101
100
10-1
T1/T2~2
liquids in porous media
T1/T2=1
bulk liquid
T1/T2~100
solid protons
Energies nouvelles, Rueil-Malmaison, France Réunion 28 du 15 novembre 2012
limit of confinement effect
T2 (ms)
T1 (ms)
resolution
limit
10-2
10-2 10-1 100 101 102 103
Pore size
protons mobility
low
high
small (1 nm) large

Fluids typing from T1-T2 map

30
Conclusions
 Fluid typing from T1-T2 maps
 T2 not smaller than 0.1 ms for water in nanopores
 Hydroxyls are below 0.1 ms, should be removed for
porosity calculation
 Methane has a large T1 signature (1s)
 Weak overlapping of the different protons
populations in a T1-T2 map
 T1-T2 signatures well understood from existing
work and NMR theory

Shale eera fleury

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