Post on 21-Apr-2015
1
Nuclear Magnetic Resonance
(NMR)
T2 Spectrum
Pore body distribution
Porosity
Bound water-Free water
Capillary Pressure-NMR spectra
Permeability
Wettability
2
Hydrogen nuclei behave as though they are tiny bar magnets; aligned with the
spin axis. In the absence of a field they are randomly oriented.
NMR
Coates et al., 1999
3
42.58 /2
!"
# #f MHz Tesla 1 Tesla= 104 Gauss !"#$%&'()*+,-(.(/01(2"3''("$
temperate latitudes
Precessional frequency, f, depends on field strength and gyromagnetic
constant,!, of a nuclei.
NMR
Coates et al., 1999
4
Net magnetization produced by aligned magnetic moments.
NMR
Coates et al., 1999
1
n
i
i
Net M m#
# # $
5
Degree of proton alignment as a function of time
NMR
Coates et al., 1999
T1 decay
1/(1 )t T
z oM M e
%# %
6
Absorbs energy from B1 field at frequency, fo, change resonance states.
NMR
Coates et al., 1999
7
Tipping the nuclei NMR
Coates et al., 1999
8
Free Induction Decay (FID)
NMR
Coates et al., 1999
9
1. Tipping
2. Precession
3. Flip 180
4. Precession
5. realignment
At a time 2& only those left in the plane realign.
NMR
Coates et al., 1999
CPMG Pulse sequence (Carr, Purcell, Meiboom, and Gill)
10
A 90o pulse followed by multiple 180o pulses creates a series of echo-spins.
NMR
Coates et al., 1999
11
A single decaying exponential.
NMR
Coates et al., 1999
12
Intercept = Porosity
Observed decays in real rocks. While they looks as if they can be fit with a
single exponential, they cannot!
NMR
Coates et al., 1999
13
Primary Controls on T2 Decay
'2 2B 2D
1 S 1 1= + +
T V T T
Surface Relaxivity
Pore Fluid Viscosity Temperature
Pore Fluid Diffusivity
Magnetic Field Gradient
Mineralogy
Pore Surface to Volume Ratio
'sandstones ~ 9- 46 (m/s
14
Material '((m/s)
Glass beads 5 - 11
Sandstone 0.37- 2.39
Quartz sand 0.013
Quartz 0.83
Silica sand 2.89 - 3.06
Sandstones 9.0 - 46
Fontainebleau ss 16
carbonate 5
clays 1.8-3.3
NMR Surface relaxivities
Dunn et al., 2002; Cheng and Vinegar, 1994; Matteson et al., 1998
15
BVI (Bulk Volume Irreducible)
The fractional part of the formation volume occupied by immobile ,
capillary-bound water.
FFI (Free Fluid Index)
The fractional part of the formation volume occupied by fluids free ,
to flow.
NMR-Fluid Partitioning
16
NMR-response
Coates et al., 1999
Pore body T2 T2-spectrum
Composite
2 _1/
0
t T
xM M e
%#
2 _ 2/
0
t T
xM M e
%#
2 _ 3/
0
t T
xM M e
%#
2 _ 4/
0
t T
xM M e
%#
2 _/
0
1
i
nt T
x i
i
M M f e%
#
# $
17
Typical NMR Interpretation
0.00
0.50
1.00
1.50
2.00
0.1 1 10 100 1000 10000
T2 ,msec
Incre
me
nta
l Po
rosity [p
u]
Cap
illa
ry B
ou
nd
Flu
id -
BV
I
Cla
y B
ou
nd
Wate
r -
CB
W
Solid
Rock
Matrix
Movable
Water
Clay-
Bound
Water
Hydro
Carbon Dry
Clay
Capillary-
Bound
Water
FFI BVI
)Effective
)Total
Fluid
Porous Media
T2_cut_off
33ms clastics
100-190 ms carbonates
18
NMR T2 Distribution- Ambient P&T A
mp
litu
de
T2, msec
0
10
20
30
40
50
60
70
80
90
100
0.01 0.1 1 10 100 1000 10000 100000 1000000
Brine (25000 ppm NaCl)
Berea, Sw = 100%
Brine (25000 ppm NaCl)
T2 = 1 sec Bulk Relaxation/ Surface Relaxation
Total Area = Porosity
Incre
men
tal P
oro
sit
y
19
Porosity Comparison
y = 0.99x
R2 = 0.99
0
5
10
15
20
25
0 5 10 15 20 25
Saturated Porosity, %
NM
R P
oro
sit
y,%
NMR-Porosity
20
NMR-Porosity
Straley et al., 1995
21
NMR-Porosity
Coates et al., 1999
22 Coates et al., 1999
T2_cutoff
clastics = 33ms
carbonates = 100-190ms
FFI
BVI
NMR- T2_cutoff
23
NMR T2 Distribution- Ambient P&T A
mp
litu
de
T2, msec
0
10
20
30
40
50
60
70
80
90
100
0.01 0.1 1 10 100 1000 10000 100000 1000000
Brine (25000 ppm NaCl)
Berea, Sw = 100%
Brine (25000 ppm NaCl)
T2 = 1 sec Bulk Relaxation/ Surface Relaxation
Bound water
Free water
capillary
24
0
1000
2000
3000
4000
5000
6000
0.01 0.1 1 10 100 1000 10000
Am
pli
tud
e,
a.u
Free Fluid
Capillary
Bound Clay Bound
Water wet!
2
1 2
T r'#
Let '*range 10-40 (m/s
2
4
3
2
2 (10 ) (4 10 )
8 10
8
%
%
#
# + + +
# +
#
r T
ms
s
m
nm
'
(
(200 nm
25
NMR-Determining T2_cutoff
Straley et al., 1995
Centrifuged
26
T2 Distribution (Berea - 33H)
0
50
100
150
200
250
300
350
0.01 0.1 1 10 100 1000 10000
T2, msec
Am
pli
tud
e
Saturated Desaturated
NMR-Determining T2_cutoff
27
T2 distribution (Berea 33H)
0
0.0005
0.001
0.0015
0.002
0.0025
0.003
0.0035
0.004
0.0045
0.005
0.01 0.1 1 10 100 1000 10000 T2, msec
Inc
rem
en
tal
Po
ros
ity
, %
0
0.05
0.1
0.15
0.2
0.25
Cu
mu
lati
ve
Po
ros
ity
, %
Incremental saturated Incrementa desaturated Cumulative saturated Cumulative desaturated
T2cutoff = 14.22 msec
NMR-Determining T2_cutoff
28
Estimation of T2 Cutoff (Centrifuge)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0.01 0.1 1 10 100 1000 10000
0
2.5
5
7.5
10
12.5
15
Incremental Porosity Cumulative Porosity
T2 Cutoff = 6 msec
100% Saturation
Swirr
T2, msec
In
cre
me
nta
l P
oro
sit
y, %
Cu
mu
lati
ve
Po
ros
ity,
%
29
5.5 4 5.8 s
Methane in Berea
Gas in Place
30
Pore Characterization
0
0.2
0.4
0.6
0.8
1
0.00001 0.0001 0.001 0.01 0.1 1 10Pore Body
Grain
Pore Throat
Pore Body
0
0.2
0.4
0.6
0.8
1
1 10 100 1000 10000 100000
NMR
Mercury Injection
2D Random porous network
pore bodies
pore throats
31
P 0
P 5
P 2
P 10
R O C KM E R C U R Y
R O C KM E R C U R Y
R O C KM E R C U R Y
R O C K
T H R O A T
P O R E
P O R E
M E R C U R Y
100 8 0 60 4 0 20 0 .0
ME
RC
UR
Y I
NJE
CT
ION
CA
PIL
LA
RY
PR
ESS
UR
E
M E R C U R Y S A T U R A T I O N ( % P O R E V O L U M E )
P 0
P 5
P 2
P 10
Traditional Mercury Injection- Concept
32 Kleinberg 1996
33
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0.01 0.1 1 10 100 1000 10000
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0.1110100100010000100000
NMR Hg Hg_Mod.
T2, msec
Capillary Pressure, psi
Wate
r S
atu
rati
on
, fr
ac.
Hg
Satu
rati
on
, fr
ac.
Comparison of Cum.T2 & Hg Injection
34
Comparison of T2 distribution & Inc. Hg Injection
0
0.2
0.4
0.6
0.8
1
0.00001 0.0001 0.001 0.01 0.1 1 10
T2, sec
, -
. /0 10 10 12 3
. /0 10 10 12 3
NMR T Relaxation:-2
1 S=!T V21 2=! "#$$%&'()"*+,'(-.'*#,"/0.1"20-+rT b2
1 2 = ! 3 "e rT th2rthwhere ! 4551*6'71"8%.5#*191,#:'7'6+ ;!e rb
2
Washburn equation:-
2<=0$>P =c rth
<=0$>! ;e P Tc
T2 distribution Inc. Hg Injection
0
0.2
0.4
0.6
0.8
1
1 10 100 1000 10000 100000
P,psi
35
0
0.2
0.4
0.6
0.8
1
0.00001 0.0001 0.001 0.01 0.1 1 10 100 1000 10000 100000
T2, sec or (2.21 psi.sec)/P
NMR HG Inv. HG
Mercury Injection rotated
about a vertical axis and
Shifted.
NMR T2 Distribution Inc. Mercury Inj.
(2.21 psi.sec)/P
5 48 (m/s
36
NMR
Coates et al., 1999
37
Schlumberger Doll Research
2 4
2_gmk aT )#44a
k = md when ) is decimal and T2 is in msec.
NMR-Permeability
** a = 0.13 for carbonates Kenyon et al. 1995.
38
22
FFIk
C BVI
)5 67 7. / . /# 8 90 1 0 12 3 2 37 7: ;
Timur_Coates
104C
Timur 4.54
210
wirr
kS
)#
wirrBVI S)#
(1 )wirrFFI S)# %
Where FFI and BVI are in porosity units (p.u.), ) is porosity as a percentage
and k is permeability in md.
NMR-Permeability
39
NMR-Permeability
4 /k )
40
Klinkenberg Permeability, md
NM
R E
sti
mate
d P
erm
eab
ilit
y, m
d
0.0001
0.001
0.01
0.1
1
10
100
1000
10000
0.0001 0.001 0.01 0.1 1 10 100 1000 10000
Fr ee Fl ui d M odel M ean T 2 M odel
kNMR = 1.08kCore0.94
R2 = 0.90
kNMR = 0.54kCore1.08
R2 = 0.88
NMR-Permeability
41
NMR-Permeability
42
NMR-log
43
1 1 1 1
1 1 1 1
w o
w bw o bo
nmr
w o
w bw o bo
S C ST T T T
W
S C ST T T T
'
'
. / . /% % %0 1 0 1
2 3 2 3#. / . /
% < %0 1 0 12 3 2 3
Tw and To are peak relaxation times for water and oil saturated rock
Tbw and Tbo are peak relaxation times for water and oil
w
o
C'
''
# and Sw and So are the water and oil saturation
NMR Wettability Index
44
Conceptual affect on NMR
45
Carbonate sample saturated with water, then crude oil
46
NMR-wettability-carbonates
_ _
_
wet water wet oil
w nmr
total
S SI
S
%#
47
Allen, D., C. Crary, B. Freedman, M. Andreani, W. Klopf, R. Badry, C. Flaum, B. Kenyon, R. Kleinberg,
P. Gossenberg, J. Horkowitz, D. Logan, J. Singer and J. White, 1997, How to use borehole
Nuclear Magnetic Resonance, Oil Field Review, 9, p34-57.
Chang, D. and H. Vinegar, 1994, Effective Porosity, Producible Fluid and Permeability in Carbonates from
NMR Logging, SPWLA 35th Annual Logging Symposium, June 19-22, 21pp.
Coates, G. R., L. Xiao and M. G. Prammer,1999, NMR Logging Principles and Applications, Gulf Publishing Co.
Houston, TX, 234 pp
Dastidar, R., C. Rai and C. Sondergeld, 2004, Integrating NMR with other petrophysical information to
characterize a reservoir, SPE89948.
Dunn, K. J., D. J. Bergmann and G. A. Latorraca, 2002, Nuclear Magnetic Resonance: Petrophysical and
Logging Applications, Handbook of Geophysical Exploration, Vol 32, Pergamon, New York, 293 pp
Ellis, D. V. and J. M. Singer, 2007, Well logging for Earth Scientists, Springer, The Netherlands, 692 pp.
Kenyon, W. E., H. Takazaki, C. Straley, P. N. Sen, M. Herron, A. Matteson and M. J. Petricola, 1995, A
laboratory study of nuclear magnetic resonance relaxation and its relation to depositional texture
and petrophysical properties-carbonate Thamama group, Mubarraz, Abu Dhabi, SPE-29886.
References
48
Kleinberg, R. L., 1966, Utility of NMR T2 distributions, connection with capillary pressure, clay effect, and
determination of the surface relaxivity parameter '2, Magnetic Resonance Imaging, 14, 7/8, 761-
767.
Lootestijin, W. and J, Hofman, 2006, Wettability-Index determination by Nuclear Magnetic Resonance, SPE
Resrv Eval. And Eng.,146-153.
Matteson, A., J. P. Tomanic, M. M. Herron, D. F. Allen and W. E. Kenyon, 1998, NMR Relaxation of Clay-Brine
Mixtures, SPE49008, pp205-211.
!"#$%&'()*()+,-../+,012,03&'456'$(,16*5(74",2(83565"(,933$:,;8()<8,=%4>(+,!1?-7059, Schlumberger
Wireline and Testing, Houston,
Sigal, R., 2002, Coates and SDR permeability:Two variations on the same theme, Petrophysics, 43, 1, 38-46.
Straley, C. D. Rossini, H. J. Vinegar, P. N. Tutunjian and C. E. Morriss, 1994, Core analysis by low field NMR
Paper 9404 Soc. Core Analysts., 43-56.
References