eni Ss.p.aA. upstream & technical services · eni s.p.a. upstream & technical services Introduced...
Transcript of eni Ss.p.aA. upstream & technical services · eni s.p.a. upstream & technical services Introduced...
eni Ss.p.aA.upstream & technical services
2013-2014 Master in Petroleum Engineering and Operations
Facies Characterization of a Carbonate Reservoir integrating Rock Type, Rock Physics and Log
Facies Models
Author: Federica Colombo
San Donato Milanese, 14 TH October 2014
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Facies Characterization of a Carbonate Reservoir integrating Rock Type, Rock Physics and
Log Facies Models
Author
Federica Colombo
Division eni S.p.A.
Upstream & Technical Services
Dept. GICA/IPET
Company Tutors
Cristiano Tarchiani
Piero Balossino
Antonio Valdisturlo
Alessandro Amato Del Monte
University Tutor
Prof. Francesca Verga
MASTER IN PETR.ENGINEERING & OPERATIONS 2013-2014
Stage Subject
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Introduction
Conclusions
3
LIST OF CONTENT
Methodology
Application
Facies Characterization of a Carbonate Reservoir integrating Rock Type, Rock Physics and
Log Facies Models
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services
Introduction
Methodology
Application
Conclusions
4
LIST OF CONTENT
Facies Characterization of a Carbonate Reservoir integrating Rock Type, Rock Physics and
Log Facies Models
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INTRODUCTION: SCOPE OF WORK
� Review of the existing workflow for characterization of a carbonatic reservoir adding data of a new well to an existing dataset
� Integrated workflow linking core data, log data and elastic properties to provide input for seismic classification to facies probabilities
� Application to a real field in offshore Venezuela
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INTRODUCTION
� Reservoir petrophysical characterization through a Facies model
• Lithologically and petrophysically homogeneous facies
• Qualitative and quantitative analysis
• Integration of data from different sources and scale
(plugs, core descriptions, RCA, SCAL, logs, CPI, …)
� Common approaches in E&P industry
• Cut-off analysis
• Core plug-based Rock Type classification
• Log-based facies classification (by cluster analysis)
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� Reservoir petrophysical characterization through a Facies model
• Lithologically and petrophysically homogeneous facies
• Qualitative and quantitative analysis
• Integration of data from different sources and scale
(plugs, core descriptions, RCA, SCAL, logs, CPI, …)
� Common approaches in E&P industry
• Cut-off analysis
• Core plug-based Rock Type classification
• Log-based facies classification (by cluster analysis)
7
INTRODUCTION
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Introduction
Methodology
Application
8
LIST OF CONTENT
Facies Characterization of a Carbonate Reservoir integrating Rock Type, Rock Physics and
Log Facies Models
Conclusions
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DepositionalFACIES
9
RESERVOIR INTEGRATED PETROPHYSICAL CHARACTERIZATION: WORKFLOW
RRTclassification
RCA
MICP k,Φ
DESCRIPTION DESCRIPTION
PORE TYPES
CLUSTER ANALYSIS
PetroelasticLOG FACIES
00
SEISMICFACIES
scale up
INVERSION
Plugs Thinsections
Cores Logs Seismic
SCAL
scale up
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METHODOLOGY: ROCK TYPE IDENTIFICATION
10
� Rock Type definition (*)
•“...unit of rock deposited under similar conditions which experienced similar diagenetic processes resulting in a unique porosity-permeability
relationship, capillary pressure profile and water saturation for a given height above the free water level”
� Analysis of core data in order to find an univocal k/φ relationship for each RRT (Reservoir Rock Type)
1. Hydraulic Flow Unit Method: Flow-zone indicator (Fzi)
2. Mercury Injection Capillary Pressure (MICP) analysis: Winland’s method (r35)
3. Power Regression method: based on existing RRTclassifications
(*) Archie, 1950
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� Introduced by Amaefule et al., 1993
� Based on a modified Kozeny-Carmen equation (1958), relating permeability to porosity and properties of the pore
network
Amaefule suggests to divide both sides of the equation by porosity and take the square root:
11
METHODOLOGY: HYDRAULIC FLOW UNIT METHOD (FZI)
Fzi: Flow Zone Indicator
RQI: Rock Quality Index
φz: Porosity group
RQI Fziφz
φe: Effective Porosity
Sgv: Pore surface area per unit grain volume
Fs: Pore shape factor
τ: Tortuosity
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METHODOLOGY: HYDRAULIC FLOW UNIT METHOD (FZI)
� When the FZI values have been identified, the k/φ equations of each Rock Type are drawn on the k-φ cross-plot
Porosity (fraction)
Perm
eab
ilit
y (
mD
)
1000
0.001
0.40.0
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METHODOLOGY: MICP DATA
p0 = 0
grains
pore throat
p1 > p0
p2 > p1
p3 > p2
Mercury Injection Capillary Pressure analysis
� Mercury is injected into an evacuated sample at increasing pressure steps and incremental injected volume is recorded
� It represents the distribution of connected pore volume accessible by throats of a given size
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0.001 0.01 0.1 1 10 100 1000
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METHODOLOGY: MICP DATA
� Results are provided with cross-plots of pore throat diameter vs. normalized pore throat distribution/Hg saturation
� Black curve: % of rock pore volume saturated by mercury at each step
� Red curve: distribution of pore volume accessible by throats of a given size
Pore throat diameter (µm)
No
rm
alized
dis
trib
uti
on
/H
g s
atu
rati
on
Pore throat diameter (µm)
1.0
0.001 10001
0.0
1.0
0.001 10001
0.0
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Pore throat diameter (µm)
15
METHODOLOGY: MICP DATA - WINLAND’S EQUATION
� An empirical relationship among porosity, uncorrected air permeability and the pore aperture corresponding to a Hg saturation of 35% (r35) has been developed by Winland (*):
Log r35 = 0.732 + 0.588 log k - 0.864 log φ
(*) Pittman, 1992
d35=0.8, r35=d35/2
35%
No
rm
alized
po
re
thro
at
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 1000
0.0
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METHODOLOGY: MICP DATA - WINLAND’S EQUATION
� When the relationship among r35, k, φ has been established for MICP samples, it is extended to all RCA samples and data are displayed on a k-φ cross-plot
Porosity (fraction)
Perm
eab
ilit
y (
mD
)
1000
0.001
0.40.0
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METHODOLOGY: POWER REGRESSION METHOD
� Based on existing RRT classifications (FZI and/or MICP, …)
� Function that represents the k- φ relationship of each RRT
1000
0.001
0.40.0 Porosity (fraction)
Perm
eab
ilit
y (
mD
)
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METHODOLOGY: CLUSTER ANALYSIS
� Non-supervised, multi step, multivariate statistical classification method for core/log facies identification
� Input data: RCA/SCAL measures (k, φ, Pc, …) - logs -interpreted curves
• training data � reference set definition on cored interval• propagation data � remaining data set classification• contingency analysis � validation of logs classification vs. core
Porosity (fraction)
Vp
Vs
rati
o
2.7
1.7
0.40.0
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LIST OF CONTENT
Introduction
Methodology
Application
Facies Characterization of a Carbonate Reservoir integrating Rock Type, Rock Physics and
Log Facies Models
Conclusions
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APPLICATION: GEOGRAPHICAL SETTING
WELL 4
WELL 3WELL 2
WELL 1 +
-
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WELL 1WELL 2 WELL 3
W3
W1
W2
21
� Early and Middle Miocene carbonates
� Distally steepened ramp
TOP CARBONATES
TOP SILICICLASTICS
TOP BASEMENT
APPLICATION: GEOLOGICAL SETTING
SW SE
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APPLICATION: GEOLOGICAL SETTING
� Main components:
1. Rhodoliths (RDST)
2. Branching Red Algae (GRST & PKST)
3. Foraminifers (GRST)
4. Corals
macroforaminifers
corals
laminarrhodolith laminar
rhodolithbranchingrhodolith
branchingred algae
1
32macroforams
4
corals
rhodoliths
branchingred algae
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APPLICATION: AVAILABLE DATA
� Pre-existing database: Well 2 & Well 3
• RRT classification based on integration of MICP analysis
(Winland), Flow Unit method (FZI) and Power Regression method
• Pore Type classification from core description
• Depositional facies classification from core description
• Log facies model based on Vp, Vs, density, GR, PHIE and the
previous core classifications
� New well data (Well 4):
• 3 cores � 456.4 ft (thin sections, core descriptions)
• 242 plugs � RCA (k, φ)
• 19/242 plugs � SCAL (MICP)
• Logs (Vp, Vs, density, GR), PHIE
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APPLICATION: WORKFLOW
24
� MICP analysis of r35 on new data � hard to fit all measures: difficult to include new data in the old classification
NEW RRT CLASSIFICATION
1. Cut-off analysis to identify non-reservoir Rock Types2. FZI method � cut-off � classes of MICP distribution � identified 5
new RRT3. Extension of new RRT classification to all wells
4. Pore Type classification5. Depositional facies classification
6. Comparison with existing log facies classification guided by old RRT (Winland, W2+W3 cores)
Associated with cluster analysis
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DepositionalFACIES
25
RESERVOIR INTEGRATED PETROPHYSICAL CHARACTERIZATION: WORKFLOW
RRTclassification
RCA
MICP k,Φ
DESCRIPTION DESCRIPTION
PORE TYPES
CLUSTER ANALYSIS
PetroelasticLOG FACIES
00
SEISMICFACIES
scale up
INVERSION
Plugs Thinsections
Cores Logs Seismic
SCAL
scale up
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APPLICATION: RRT CLASSIFICATION
RRT 1
Porosity (fraction)
Perm
eab
ilit
y(m
D)
1000
0.001
0.450.0
231 - W2
338 - W3
340 - W3
1 - W4
8 - W4
9 - W4
14 - W4
20 - W4
RRT1 - all wells
231 - W2
338 - W3
340 - W3
1 - W4
8 - W4
9 - W4
14 - W4
20 - W4
RRT1 - all wells
Pore throat diameter (µm)
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 10000.0
Pore throat diameter (µm)
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 10000.0
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APPLICATION: RRT CLASSIFICATION
RRT 1
RQ
I(R
ock Q
uality
In
dex)
Porosity (%)
10.0
WELL 4
0.0 0.35
0
8
231 - W2
338 - W3
340 - W3
1 - W4
8 - W4
9 - W4
14 - W4
20 - W4
RRT1 - all wells
231 - W2
338 - W3
340 - W3
1 - W4
8 - W4
9 - W4
14 - W4
20 - W4
RRT1 - all wells
Pore throat diameter (µm)
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 10000.0
Pore throat diameter (µm)
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 10000.0
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APPLICATION: RRT CLASSIFICATION
WELL 4: FREQUENCY HISTOGRAMFreq
uen
cy
FZI classes
2.7
1
0.40.05
� Flow Unit Method: • Computation of frequency histogram of FZI for each well
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APPLICATION: RRT CLASSIFICATION
� Flow Unit Method: • Computation of frequency histogram of FZI for each well• Common cut-off definition• Analysis extended to Well 2 and Well 3
WELL 4: FREQUENCY HISTOGRAM
0.1
0.21
0.32
0.51.25
Freq
uen
cy
FZI classesRRT2 RRT3 RRT4 RRT5 RRT6
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APPLICATION: RRT CLASSIFICATION
� Cut off of FZI used as reference to classify pore throat distribution curves from MICP analysis
� Results: 5 RRT identified
� Classification extended to W2 & W3
R
R
T
2
R
R
T
3
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n / H
g s
atur
atio
n
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n / H
g s
atur
atio
n
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n / H
g s
atur
atio
n
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n / H
g s
atur
atio
n
Pore throat diameter, µµµµm
R
R
T
5
R
R
T
4
R
R
T
6
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rma
lized
Po
re th
roat
dis
trib
utio
n / H
g s
atu
rati
on
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n /
Hg
sat
urat
ion
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n / H
g s
atu
ratio
n
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rma
lized
Po
re th
roat
dis
trib
utio
n / H
g s
atu
rati
on
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n / H
g s
atur
atio
n
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n / H
g s
atur
atio
n
Pore throat diameter, µµµµm
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0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rma
lized
Po
re th
roat
dis
trib
utio
n / H
g s
atu
rati
on
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n /
Hg
sat
urat
ion
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roa
t dis
trib
utio
n / H
g s
atu
rati
on
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n / H
g s
atur
atio
n
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000N
orm
aliz
ed P
ore
thro
at d
istr
ibut
ion
/ Hg
sat
urat
ion
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n / H
g s
atur
atio
n
Pore throat diameter, µµµµm
31
APPLICATION: RRT CLASSIFICATION
RRT 4RRT 4
104 - P2
195 - P2
304 - P2
109 - P3
258 - P3
89 - P4
98 - P4
136 - P4
221 - P4
RRT4 - all wells
Pore throat diameter (µm)
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 10000.0
Pore throat diameter (µm)
104 - P2
195 - P2
304 - P2
109 - P3
258 - P3
89 - P4
98 - P4
136 - P4
221 - P4
RRT4 - all wells
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 10000.0
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APPLICATION: RRT CLASSIFICATION
RRT 4
Porosity (fraction)P
erm
eab
ilit
y(m
D)
1000
0.001
0.450.0
104 - P2
195 - P2
304 - P2
109 - P3
258 - P3
89 - P4
98 - P4
136 - P4
221 - P4
RRT4 - all wells
Pore throat diameter (µm)
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 10000.0
Pore throat diameter (µm)
104 - P2
195 - P2
304 - P2
109 - P3
258 - P3
89 - P4
98 - P4
136 - P4
221 - P4
RRT4 - all wells
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 10000.0
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0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rma
lized
Po
re th
roat
dis
trib
utio
n / H
g s
atu
rati
on
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n /
Hg
sat
urat
ion
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roa
t dis
trib
utio
n / H
g s
atu
rati
on
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n / H
g s
atur
atio
n
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000N
orm
aliz
ed P
ore
thro
at d
istr
ibut
ion
/ Hg
sat
urat
ion
Pore throat diameter, µµµµm
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.001 0.01 0.1 1 10 100 1000
No
rmal
ized
Po
re th
roat
dis
trib
utio
n / H
g s
atur
atio
n
Pore throat diameter, µµµµm
33
APPLICATION: RRT CLASSIFICATION
RRT 6
0.001 0.01 0.1 1 10 100 1000Pore throat diameter, µµµµm
10 - P2
43 - P2
47 - P2
66 - P2
73 - P2
9 - P3
11 - P3
12 - P3
20 - P3
27 - P3
31 - P3
37 - P3
40 - P3
52 - P3
57 - P3
62 - P3
65 - P3
339 - P3
RRT6 - all wells
0.001 0.01 0.1 1 10 100 1000Pore throat diameter, µµµµm
10 - P2
43 - P2
47 - P2
66 - P2
73 - P2
9 - P3
11 - P3
12 - P3
20 - P3
27 - P3
31 - P3
37 - P3
40 - P3
52 - P3
57 - P3
62 - P3
65 - P3
339 - P3
RRT6 - all wells
Pore throat diameter (µm)
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 1000
0.0
Pore throat diameter (µm)
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 10000.0
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APPLICATION: RRT CLASSIFICATION
RRT 6
Porosity (fraction)P
erm
eab
ilit
y(m
D)
1000
0.001
0.450.0
0.001 0.01 0.1 1 10 100 1000Pore throat diameter, µµµµm
10 - P2
43 - P2
47 - P2
66 - P2
73 - P2
9 - P3
11 - P3
12 - P3
20 - P3
27 - P3
31 - P3
37 - P3
40 - P3
52 - P3
57 - P3
62 - P3
65 - P3
339 - P3
RRT6 - all wells
0.001 0.01 0.1 1 10 100 1000Pore throat diameter, µµµµm
10 - P2
43 - P2
47 - P2
66 - P2
73 - P2
9 - P3
11 - P3
12 - P3
20 - P3
27 - P3
31 - P3
37 - P3
40 - P3
52 - P3
57 - P3
62 - P3
65 - P3
339 - P3
RRT6 - all wells
Pore throat diameter (µm)
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 1000
0.0
Pore throat diameter (µm)
Norm
ali
zed
dis
trib
uti
on
/H
g s
atu
rati
on
1.0
0.001 10000.0
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DepositionalFACIES
35
RESERVOIR INTEGRATED PETROPHYSICAL CHARACTERIZATION: WORKFLOW
RRTclassification
RCA
MICP k,Φ
DESCRIPTION DESCRIPTION
PORE TYPES
CLUSTER ANALYSIS
PetroelasticLOG FACIES
00
SEISMICFACIES
scale up
INVERSION
Plugs Thinsections
Cores Logs Seismic
SCAL
scale up
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APPLICATION: PORE TYPES CLASSIFICATION
FR
WPP
BIOMOP
PBP
� Approach:
• Thin section description (W4)
• Core description (W2, W3 & W4)
� Results:
• Pore Type family definition▪ Interparticle porosity PBP
▪ Intraparticle porosity WPP
▪ Biomoldic porosity BIOMOP
▪ Microporosity GEN_MICROP
▪ Vuggy porosity VUGP
▪ Fracture related porosity FR
• Logs of Pore Type
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APPLICATION: PORE TYPES CLASSIFICATION
� Approach:
• Thin section description (W4)
• Core description (W2, W3 & W4)
� Results:
• Pore Type family definition▪ Interparticle porosity PBP
▪ Intraparticle porosity WPP
▪ Biomoldic porosity BIOMOP
▪ Microporosity GEN_MICROP
▪ Vuggy porosity VUGP
▪ Fracture related porosity FR
• Logs of Pore Type
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DepositionalFACIES
RESERVOIR INTEGRATED PETROPHYSICAL CHARACTERIZATION: WORKFLOW
RRTclassification
RCA
MICP k,Φ
DESCRIPTION DESCRIPTION
PORE TYPES
CLUSTER ANALYSIS
PetroelasticLOG FACIES
00
SEISMICFACIES
scale up
INVERSION
Plugs Thinsections
Cores Logs Seismic
SCAL
scale up
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� Approach: • Core description (W2, W3 & W4)
� Results: • Depositional facies classification
▪ 8 facies defined in W2 & W3▪ W4 has a new facies: FACIES 9
39
APPLICATION: DEPOSITIONAL FACIES CLASSIFICATION
�
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� Approach:
• Core description (W2, W3 & W4)
� Results:
• Depositional facies classification
▪ 8 facies defined in W2 & W3▪ W4 has a new facies: FACIES 9▪ FACIES 1 (rhodolithic RDST)
▪ Best quality in W2 & W3 ▪ Rare, thin and with poorer properties in W4
• Definition of a continuous sedimentologicalfacies log in W4 for comparison with W2 & W3
40
APPLICATION: DEPOSITIONAL FACIES CLASSIFICATION
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DepositionalFACIES
RESERVOIR INTEGRATED PETROPHYSICAL CHARACTERIZATION: WORKFLOW
RRTclassification
RCA
MICP k,Φ
DESCRIPTION DESCRIPTION
PORE TYPES
CLUSTER ANALYSIS
PetroelasticLOG FACIES
00
SEISMICFACIES
scale up
INVERSION
Plugs Thinsections
Cores Logs Seismic
SCAL
scale up
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� Log facies calibrated on W2 and W3 andpropagated to W4 (RCA & facies not yet available)
� Log facies model from cluster analysis
• TRAINING SET � VPVS, AIMP, DTCO, RHOZ, NPHI, GR, PHIE
• ASSOCIATED LOGS � DEPOSITIONAL FACIES, PORE TYPES,
PRE-EXISTING RRT (W2, W3) CLASSIFICATIONS
• Starting from 25 classes
� Results:
• Log facies definition � 5 log facies
APPLICATION: PETROELASTIC LOG FACIES CHARACTERIZATION
0
0.001
45
1000
Porosity (%)
Perm
eab
ilit
y(m
D)
42
2.1
2.9
12040 DTCO (µs/ft)
Den
sit
y
(g
/cc)
2.6
1.6
IP (FRMB)
Vp
Vs
(FR
MB
)
160007000
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� Both sets have been re-grouped to optimize the correlation
� Anyway, the correlation is poor, especially for the best RRT (5&6): the highest frequencies are not restricted to the matrix diagonal
Log facies
APPLICATION: PETROELASTIC LOG FACIES CHARACTERIZATION
Log facies
Rock Types
Porosity (fraction)
Perm
eab
ilit
y(m
D)
Rock Types
1000
0.001
0.400.0
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� Log facies well defined considering acoustic impedance (PIMP)
� Facies have a wide range of VpVs ratio � can be optimized
APPLICATION: PETROELASTIC LOG FACIES CHARACTERIZATION
Vp
Vs
(FR
MB
)
IP (FRMB)
2.5
1.7
160006000
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� GAMMAK (*) � frame flexibility factor
� Describes the flexibility of the rock frame due to the pore structures
� Computed from a Rock Physics model (EBT, Extended Biot Theory)
� Different values of GammaK in the same log facies
APPLICATION: PETROELASTIC LOG FACIES CHARACTERIZATION
High GAMMAK ����
weak rock frame
Low GAMMAK ����
stiff rock frame
Vp
Vs
(FR
MB
)
IP (FRMB)
2.5
1.7
160006000
200
(*) Sun, 2000-2004-2011
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� FK (*) � frame stiffness
� Describes the stiffness of the rock frame due to porosity and pore network
� Computed from a Rock Physics model (EBT, Extended Biot Theory)
� Different values of FK in the same log facies
APPLICATION: PETROELASTIC LOG FACIES CHARACTERIZATION
Low FK ����
low rock strenghtHigh FK ����
high rock strenght
Vp
Vs
(FR
MB
)
IP (FRMB)
2.5
1.7
160006000
200
(*) Sun, 2000-2004-2011
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LIST OF CONTENT
Introduction
Methodology
Application
Facies Characterization of a Carbonate Reservoir integrating Rock Type, Rock Physics and
Log Facies Models
Conclusions
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CONCLUSIONS
� New RRT classification to include W4 showing different petrophysical characteristics and facies
� Pore Types and Depositional facies classifications extended to W4
� Analysis of existing Log facies classification versus new RRT:
• Poor correlation between log facies and new RRT• (checked using contigency analysis)
• VpVs ratio not well discriminated
• Variations in GammaK and FK values within the same log facies
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CONCLUSIONS: WAY FORWARD
� Requirements for a new log classification:
• Changing some input logs in the training data
• Taking more into account VpVs ratio
• Accounting for new RRT classification
• Considering elastic parameters (GammaK, FK)
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ACKNOWLEDGEMENTS
I would thank Eni Upstream & Technical Services
Management for permission to present this work and
related results and colleagues of GICA dept.
Special thanks to EACH ONE OF MY TUTORS
for the technical support.
THANK YOU FOR YOUR ATTENTION !