gp170/2001 #8 la cira case studypangea.stanford.edu/~jack/gp170/gp170#8.pdf1 la cira case study...
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La Cira Case StudyGP170/2001 #8
Tectonic map of Colombia
La Cira - Infantas Oil Field:•Discovered in 1918•OOIP: 3490 MMBO•1742 wells•Production: 721 MMBO•Recovery factor (20%)
2100 150
600
800
1000
1200
1400
1600
1800
2000
2200
GR
Dep
th (ft
)
1879
0 0.5 1Sw
1879
60 80 100120
800
1200
1600
2000
2400
2800
3200
GR
Dep
th (ft
)
1880
0 0.5 1Sw
1880
60 80 100120
500
1000
1500
2000
2500
3000
GR
Dep
th (ft
)
1882
0 0.5 1Sw
1882
Reason for Low Recovery Rate -- Heterogeneity
4 6 8Ip
1879
4 6 8 10Ip
1880
4 6 8 10Ip
1882
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Geological Heterogeneity is Accompanied by Acoustic Heterogeneity
0 0.5 1
4100
4200
4300
4400
4500
4600
4700
Vsh and Sw
Dep
th (ft
)
1757
0 0.5 1
4300
4350
4400
4450
4500
Vsh and Sw
Dep
th (ft
)
1757
3.0 3.5 4.0Vp (km/s)
1757
3.0 3.5 4.0Vp (km/s)
1757
0 0.5 1
4500
4550
4600
4650
4700
4750
Vsh and Sw
Dep
th (ft
)
1757
3 3.5 4Vp (km/s)
1757
Reservoir heterogeneities compartmentalize reservoirsinto flow units of variable lateral and vertical extent,preventing efficient drainage and sweep of reservoirs
Classification of reservoir heterogeneity types(Weber, 1993).
Deposition Diagenesis Deformation
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Reservoir Heterogeneity
• Fieldwide scale• Interwell scale• Well-bore scale
Levels of reservoir heterogeneity (Weber, 1986 and Slatt et al., 1993)
(From “Infield natural gas reserve growth - Concepts andtechnologies for reserve appreciation”, BEG )
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Lithofacies and Permeability
Major types of geological and petrophysical data applied to flow unit zonation of a well (Ebanks et al. 1993 )
0.1
1
10
100
1000
0.1 0.2 0.3
Per
mea
bilit
y (m
D)
Porosity
LC 1880 + 1891
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Fault-Related Heterogeneity
Normal Faults
GP170/2001 #8
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E
N
Isometric Projection of Velocity Strata SliceParallel to B4 Seismic Marker
35 ms (Two-Way-Travel-Time) Below B4
La Cira Norte
Seismic Image of Reservoir -- La Cira NorteGoal -- Transform Seismic Image into Lithology
Rock Physics’ Task -- Translate SeismicImages into Reservoir Property Images
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Large-Scale Rock PhysicsGP170/2001 #8
2.1
2.2
2.3
2.4
2.5
2.6
50 75 100 125 150 175
RH
OB
GR
188218801879
4
6
8
10
50 75 100 125 150 175
P-I
mped
ance
GR
188218801879
0
0.1
0.2
0.3
0.4
50 75 100 125 150 175
Por
osit
y
GR
188218801879
0.2
0.3
0.4
50 75 100 125 150 175
Poi
sson
's R
atio
GR
1882
4
6
8
10
0 0.1 0.2 0.3
P-I
mped
ance
Porosity
188218801879
0.2
0.3
0.4
0 0.1 0.2 0.3
Poi
sson
's R
atio
Porosity
1882
0.2
0.3
0.4
5 6 7 8 9
Poi
sson
's R
atio
P-Impedance
1882
9
0.2
0.3
0.4
5 6 7 8 9
Poi
sson
's R
atio
P-Impedance
1882
5 6 7 8 9
P-Impedance
1882
>2984 ft
5 6 7 8 9
P-Impedance
1882
>1851 ft< 2026 ft
5 6 7 8 9
P-Impedance
1882
>2984 ft
>1851 ft< 2026 ft
1.0 1.5 2.0
Vs (km/s)
1882
50 75 100
1800
2000
2200
2400
2600
2800
3000
GR
Dep
th (ft
)
1882
0 0.5 1
Sw
1882
2 3 4
Vp (km/s)
1882
4 6 8 10
P-Impedance
1882
0.2 0.3 0.4
Poisson's Ratio
1882
0 0.1 0.2 0.3
Porosity
1882
Effect of Depth on P/S PropertiesGP170/2001 #8
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Effect of Depth on P-Impedance
4
6
8
10
0 0.1 0.2 0.3
P-I
mped
ance
Porosity
1882
50 60 70 80 90 100 110 120
430
435
440
445
GR
Dep
th (ft
)
50 60 70 80 90 100 110 120
1530
1540
1550
1560
GR
Dep
th (ft
)
50 60 70 80 90 100 110 120
3154
3156
3158
3160
3162
GR
Dep
th (ft
)
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2 2.5 3 3.5 4Vp (km/s)
Rock Physics Observations and Transforms
3
4
5
0 0.1 0.2 0.3
0 < Clay < 5%10% < Clay < 20%25% < Clay < 35%
P-W
AW
E V
ELO
CIT
Y (km
/s)
POROSITY2
Consolidated SandstonesDRY at 40 MPa
Why does not shale content affectimpedance-porosity trend in La Cira?
GP170/2001 #8
0 0.2 0.4 0.6 0.8 1
2850
2900
2950
3000
3050
Sw and VSHALE
DR
KB
(ft
)
LC 1880
Sw
VSHALE
4
5
6
7
8
9
10
0 0.2 0.4 0.6 0.8 1
LC 1880: Below 2800 ft DRKB
P-I
mped
ance
VSHALE
S A N D SHALE
0
0.1
0.2
0.3
0 0.2 0.4 0.6 0.8 1
PO
RO
SIT
Y
VSHALE
4
5
6
7
8
9
10
11
0 0.1 0.2 0.3
P-I
MPE
DA
NC
E
POROSITY
Expectedtrend
12
Core Data: Shale is not ClayGP170/2001 #8
1
2
3
4
5
6
7
0 0.1 0.2 0.3
Is (km
/s
g/cm
3) at
10 M
Pa
Porosity
Dry Rock
SAND
SHALE
4
6
8
10
12
0 0.1 0.2 0.3
Ip (km
/s
g/cm
3) at
10 M
Pa
Porosity
Dry Rock
SAND
SHALE
SAMPLES FROM SHALY ZONESSample ID Porosity Quartz Clay Feldspar Calc+Dolom Other1880/2443' 0.033 0.610 0.290 0.080 0.000 0.0201882/2743' 0.037 0.470 0.190 0.030 0.290 0.0201879/1852' 0.054 0.720 0.260 0.010 0.000 0.0101880/2452' 0.057 0.650 0.250 0.070 0.000 0.0301882/2971' 0.061 0.560 0.240 0.110 0.050 0.0401880/2457'10" 0.062 0.620 0.150 0.180 0.050 0.0001880/2454' 0.062 0.660 0.240 0.060 0.020 0.0201882/2612' 0.069 0.720 0.250 0.020 0.000 0.0101880/2439' 0.073 0.680 0.220 0.090 0.000 0.0101880/2417' 0.084 0.660 0.210 0.130 0.000 0.0001879/1868' 0.091 0.650 0.320 0.020 0.000 0.0101879/1923' 0.091 0.760 0.190 0.030 0.000 0.0201879/1826' 0.092 0.770 0.150 0.060 0.000 0.0201880/2432'4" 0.093 0.660 0.270 0.050 0.010 0.0101879/1872' 0.103 0.660 0.180 0.140 0.000 0.0201880/2399' 0.106 0.570 0.200 0.040 0.170 0.0201879/1919' 0.106 0.830 0.150 0.010 0.000 0.0101879/1871' 0.116 0.680 0.180 0.120 0.000 0.0201879/1805' 0.131 0.680 0.110 0.210 0.000 0.0001879/1877' 0.137 0.720 0.140 0.120 0.010 0.0101879/1902' 0.178 0.820 0.100 0.080 0.000 0.000
0 0.2 0.4 0.6 0.8 1
1800
1850
1900
VSHALEPOROSITYCLAY
Porosity, Clay, VSHALE
DR
KB
(ft
)
LC 1879
13
4
5
6
7
8
9
10
11
0 0.1 0.2 0.3
P-W
ave
Imped
ance
Total Porosity
SHALE
SANDSANDCHANNEL
SHALE
“Rough” InterpretationGP170/2001 #8
14
B4 - 20 ms
B4 - 10 ms
“Rough” Interpretation of Images
GP170/2001 #8
0 0.5 1
3600
3700
3800
3900
4000
4100
4200
VSHALE
Dep
th (ft
)
1783
50 100 150GR
1783
B4
15
B4 - 5 ms
B4
“Rough” Interpretation of Images
GP170/2001 #8
0 0.5 1
3600
3700
3800
3900
4000
4100
4200
VSHALE
Dep
th (ft
)
1783
50 100 150GR
1783
B4
16
“Rough” Interpretation of Images
GP170/2001 #8
B4 + 5 ms
B4 + 10 ms
17
Careful Rock Physics
GP170/2001 #8
3
4
5
6
7
8
9
10
11
0 0.1 0.2 0.3
P-I
mped
ance
Porosity
1880
3
4
5
6
7
8
9
10
11
50 75 100
P-I
mped
ance
GR
1880
50 75 100 125
1500
2000
2500
3000
GR
Dep
th (ft
)
1800
60 70 80 90
2560
2565
2570
2575
2580
2585
2590
GR
Dep
th (ft
)
1800Select
0.1 0.2Porosity
1800Select
6 7 8P-Impedance
1800Select
0 0.5 1Sw
1800Select
Sonic data are from invaded formation
18
Rock Physics Diagnostic
GP170/2001 #8
3
4
5
6
7
8
9
10
11
0 0.1 0.2 0.3
P-I
mped
ance
Porosity
1880
Brine
Oil
Gas
Cement
3
4
5
6
7
8
9
10
11
0 0.1 0.2 0.3
P-I
mped
ance
Porosity
1880
Brine
Clean(80% Quartz + 20% Feldspar)
Clean(20% Quartz + 20% Feldspar
+ 60% Clay)
0.1
0.2
0.3
0.4
5 6 7 8 9
Poi
sson
's R
atio
P-Impedance
Cleanw/Gas
Cleanw/Oil
Cleanw/Water
Clayw/Water
Effective-Medium Models
Elastic-Acoustic Impedance Transform for porosity cube
0
0.1
0.2
0.3
3 4 5 6 7 8 9
Por
osit
y
P-Impedance
Brine
Oil
Gas
Clay/Brine