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