Transcript No Slide Title

MRIL OVERVIEW
Team One
NUMAR / HALLIBURTON
Crucial Formation Evaluation Questions
• What is the storage capacity (e and t ) in a
Complex Lithology Environment ?
• Are there hydrocarbons,
 what types of hydrocarbons and,
 how are they distributed?
• What is the permeability (deliverability)?
• Will the formation produce water free? (what is
irreducible saturation (BVI))
MRIL answers them all
Medical MRI
“Thin Slice”
Image
Only Fluids
are Visible
H
Oilfield MRI
(Relaxation Time Spectrum)
Solids….invisible to MRI
Fluids
irreducible
rock matrix
dry clay
clay bound
movable
water
hydrocarbon
clay bound
T2 relaxation times
the measurement
T1 Magnetization
no measurement
0
1
2
3
4
5
6
time, sec.
8 9 10
11
12
13
14 …….
Magnetic Dipole
H
Proton
Hydrogen
NMR works with Protons - Hydrogen -> H2O and CxHy+++
Random Orientation in Natural State
N
S
N
N
S
S
N
Bo
S
t =0
Magnetization Buildup
N
N
S
N
S
N
S
Bo
S
M
N
S
Wait time (sec)
Bo=External Field
M=Bulk Net Magnetization
t = 0.75 sec
Buildup at 95 % polarization
N
N
S
S
N
N
N
S
S
N
S
N
Bo
N
S
S
N
S
N
S
N
N
S
M
S
S
Wait time (sec)
Bo=External Field
M=Bulk Net Magnetization
t = 6.0 sec
T1 build-up and T2 decay
ML
B0
MT
T1
Magnetization
T2
T1 characterizes the rate at which longitudinal magnetization builds up
T2 characterizes the rate at which transverse magnetization decays
NMR Experiment Timing
M ||  1  exp  time / T1 
Mo
T1 = 400 msec
M || to Bo
(longitudinal
component)
0
M^  exp time / T2 
TW
Mo
T2 = 250 msec
M ^ to Bo
(transverse
component)
0
TE
B1
TX
RF field
0
0
0.5
1.0
adapted from Murphy, D.P., World Oil, April 1995
1.5
2.0
2.5
3.0
time, seconds
3.5
4.0
4.5
5.0
T1 Magnetization build up
Water: T1 = 0.33s
100
80
% Polarization
Light Oil: T1 = 2s
60
Gas: T1 = 3s
40
20
0
0
1
2
3
4
5
6
7
8
9
t (s)
3 * T1 = Tw
95% Polarization
% Polarization *  = Measured Porosity
10
11
12
Effects of Chemistry and Texture on T1 and T2
(water filled)
Low Porosity
Clean Cgr Sandstone
T1 Build-up
T2 decay
Low Porosity
Shaly Fgr Sandstone
Higher Porosity
Shaly Cgr Sandstone
0
1
2
3
4
5
Time, sec.
6
7
8
9
10
MRIL in Wellbore
Borehole
MRIL Probe
24 “
Sensitive
Volume
Cylinders
(each 1 mm thick
at 1 mm spacing)
Permanent
Magnet and
Field
Pulsing RF
and receiving
RF Antenna
 16”
MRIL Diameter of Investigation
Multi - Frequency Series C Tool
Frequency 1
Frequency 2
Borehole
Frequency 3
Sonde
Sleeve
Wall
Formation
Magnet
S
N
Mud
RF
Antenna
1
2
3
6”
16”
NUMAR Corp., 1995
Measured signal decay
TE
Amplitude = Porosity
35
Amplitude (pu)
30
25
20
Decay rate (1 / T2) =>
rock & fluid information
15
10
5
0
0
50
TE
100
150
time (ms)
200
250
300
3 Relaxation Mechanisms
Echo Amplitude vs Time
Effect of Each
Mechanism is Additive
Amplitude
1
1
1
1



T2 T2 B T2 D T2 S
Bulk Relaxation - T2B
Intrinsic Property of fluid
Diffusion - T2D
Molecular Movement
Surface Relaxation - T2S
Pore-walls cause rapid dephasing
Time, msec.
Pore Size and T2 (Water)
1
T2
 2 S
V
T2 = relaxation time
constant.
S = surface area of
the pore.
V = volume of
the pore.
T2
time
T2
time
T2
time
T2
time
2 = relaxation rate
constant.
T2
time
Surface Relaxation Mechanism
Water Filled Pores
Small Pore Sizes = Rapid Decay Rate
100
90
Large Pore Sizes =
Slow Decay Rate
80
70
60
50
40
T2 -1 S/V)
30
20
10
0
0
100
200
300
400
500
Time, msec.
600
700
800
900
1000
Data Processing - Inversion
MAP
“Inversion”
Processing
Spin-echo data
T2 Spectrum “Best Fit”
15
Incremental Porosity [pu]
35
30
25
20
15
10
5
0
50
100
150
200
250
300
T2i are pre-selected:
T2i = 4, 8, 16, 32, 64, 128, 256, 512, 1024...
12.0
10
6.0
5.0
5
3.0
4.5
2.0
0.5 0.5
0
0
FFI
BVI
1
10
100
1000
T2 [ms]
Water-saturated rock: T2 = V/S
NUMAR Corp., 1995
10000
40
35
phi-NMR (pu)
30
25
20
15
10
5
0
0
5
10
15
20
25
phi-core (pu)
30
35
40
Permeability Chart E-4
0.5
k
1
2
 C 
3
E-4
Swirr
Where C = 250
0.4
Porosity
0.3
1000
0.2
100
10
1.0
0.1
k (md)
0
0
0.2
0.4
Swir
0.6
0.8
1
MRIL Permeability
• MPERM = ((MPHI/10)2 (MFFI/MBVI))2
MPHI - MRIL Porosity (porosity units)
MBVI - MRIL Bulk Volume Irreducible
MFFI - MRIL Free Fluid Index
MPERM - Permeability (millidarcies)
10000
K_NMR (mD)
1000
100
10
1
0.1
0.01
0.01
0.1
1
10
K_air (mD)
100
1000
10000
Differential Echo / Spectrum Method
TW(1) = 12.208 (s) TE(1) = 1.2 (ms)
1
10
FMW
OBMF
Gas
T2 (ms)
100
1000
T2 (ms)
100
1000
TW(2) = 1 (s) TE(2) = 1.2 (ms)
1
10
Dif Spec; TW = 12.208 & 1 (s)
1
10
FMW
T2 (ms)
100
OBMF
Gas
1000
Effect of Diffusion on T2
0.0
100
200
300
Time, milliseconds
400
0.8
3
Incremental Volume, cm
Spacing of Echoes
0.5 milliseconds
1.0 milliseconds
2.0 milliseconds
5.0 milliseconds
10.0 milliseconds
E
in ffe c
Tim t o
e fD
Do iff
m usio
ai n
n
Amplitude
0.9
500
0.7
Effec t of diffusion
on T2 Spec trum
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0.1
1.0
10
100
1000
Relaxation Time (T2), milliseconds
10000
Diffusion - Shifted Spectrum Method
TW(1) = 7.996 (s) TE(1) = 1.2 (ms)
1
10
T2 (ms)
FMW
OBMF
Oil
100
1000
100
1000
TW(2) = 7.996 (s) TE(2) = 6 (ms)
1
10
T2 (ms)
Pay Recognition from EDM
The Effect of Long TE
GR
0
GAPI
DEPTH
LLD
DEPTH
feet
LLS
FEET
200
0.2
OHMM
4
200
1.2 msec. TE
Fully Polarized
msec.
2048 4
T2DW
3.6 msec. TE
Fully Polarized
msec.
T2DW
2048 4
4.8 msec. TE
Fully Polarized
msec.
T2DW
2048
Depth
0
8
-100
100
XX200
Gamma Ray
(GAPI)
Caliper (in)
150 0.2
18 0.2
SP (mv)
100
Bins 1 - 8 (PU)
0
20
Shallow
Resistivity
Deep
Resistivity
Permeability
(md)
20
20 2
20
2000
T2 Distribution
Variable Density 2048
(milliseconds)
60
Density Porosity
0
60
Neutron Porosity
0
60
60
BVI
0
Effective Porosity 0
Pick your choice
• What’s new ?
• Low resistivity pay
• Extra pay identified
• Shale, Huh ?
• Integrating core data and MRIL data