© TOC, 2011
T
O
C
Preliminary Results of Pembina
Cardium Core Analysis
C.R. Clarkson and N. Solano (PhD Candidate)
Outline
• Objectives
• Well Locations
• Sampling and Measurements
• CT Scans
• N2 Adsorption Analysis
T
O
C
• Comparison to Bakken and 2WS
• SANS/USANS
• Future Work
1
Objectives
• Select low-permeability oil reservoir samples from the
Cardium Formation to perform preliminary laboratory
experiments
• Use X-Ray CT Scans to evaluate changes in rock density
and porosity and use to evaluate locations for
permeability measurements (+ density of measurements)
• Use low-pressure adsorption and small-angle neutron
scattering (SANS and USANS) to establish pore structure
characteristics by facies
 To date, only “muddier” intervals have been studied
• Establish controls on pore structure variation
• Establish relationship between pore structure and
permeability
2
Sampling/Measurements
• CORES SAMPLED / ANALYZED:
1. 08-17-049-06W5, CORE #1, BOXES 3 – 13
2. 08-04-049-06W5, CORE #4, BOXES 5 – 11
3. 04-24-049-07W5, CORE #1, BOX 11; CORE #2, BOXES 1 – 5; CORE #3,
BOXES 1 – 4 (FUTURE)
• MEASUREMENTS (to date):
1. Coreplugs taken from 8-17 and sub-sampled for SANS/USANS (discs
prepared) at NIST (1/2011) and ORNL (3/2011)
2. N2 adsorption analysis performed on 8-17 coreplugs for surface area/PSD
(8/2011)
3. 8-17 and 8-4 full-diameter cores were “scout” (CT) scanned to identify
locations for axial scans (7/2011)
4. Axial (CT) scans performed on 8-17 and 8-4 (8/2011)
5. Pulse-decay permeability measurements performed on 8-17 coreplugs
3
LOCATIONS
WITH
CORES TO
TOP OF
THE CARDIUM
SS SAMPLE
-5
-5 3
-5 5 0
-5 7 0
-5 8 0
10
-6
0
0
-5 3
-5 4 0
646000
648000
40
644000
EAST (UTM 11), [m]
-5 7
0
0
-5 9 0
-590
-560
642000
40
0
-5
5000m
0
-6 1
4
-6
-6 0
30
20
-6
-6
-6 2 0
00
4000
640000
-520
0
-5 1 0
8-4-49-6W5
50
-6
3000
1:78125
610
-6638000
00
0
40
-5
-5
80
0
636000
-5 0
0
-5 2
70
-5
-6 0
-
90
0
59
90
30
0
-5 5 0
-580
2000
-4 7 0
00
-4
-5 6 0
5896000
-5
0
0
-5 4
5904000
80
80
-5 1
20
-4 8
-5
0
N O R TH -(U
T M 11), [m ]
5
-4
-4 9 0
40
-5
-5 5
-5 5
60
0
-4 7 0
-5 0 0
0
20
-5
5900000
-4 9 0
-5 1
-5
30
0
5898000
10
-4 7 0
08-17-49-6W5
-600
1000
- 47 0
-5 1
-5
0
0
-5
40
-5
-5 6 0
0
30
-5
-5
634000
-4 6
90
00
0
50
-5 2 0
90
0
-6 1
-4 7 0
-4 8 0
-4
-5
-5 2
-5
-5
-570
-5
650000
-5 0 0
-5
-5 8
0
-540
-5 6 0
80
648000
4-24-49-7W5
-5 7 0
-5
646000
-4 8
-5 1
0
-5 5
0
10
20
-5 3
50
-5 7
644000
-540
-5
60
642000
-5
50
-5
640000
-5
-450
-460
-470
-480
-490
-500
-510
-520
-530
-540
-550
-560
-570
-580
-590
-600
-610
60
-620 -5
-630
-640
-650
-660
-670
-680
-690
-5
5902000
638000
Depth
0
5894000
636000
-5 3 0
634000
650000
-550
-5
-560 contour map:5 0top of the Cardium SS
Structure
4
MD
(m)
SP
55
60
65
70
75
Res (16" NORMAL)
RESIT
0
20
08-17-049-06W5
40
1330
1335
CZ
1340
1345
1350
1355
1360
1365
1370
Cardium A
a
1375
1380
1385
1390
1395
1400
1405
b
5
100/08-17-049-06W5/00 [TVD]
69.34 CN BN
TVD
1:275
SANS CTS SLABSBLS PROK XRF
1.00
1.00
1.00
SN
SN
SN
50.00 0.01 KMAX
50.00 0.01 K90
50.00 0.01 KV
100.00 0.0000 PHIC
100.00
100.00
0.2000
2
1
AVAILABLE RCA (Whole core
diam.)
Kmax, PHI, GRAIN DENSITY
4
3
Kcard_ss
CTS
C TS
SLAB
SBLS
PR OK
XR F
1
7
5
8
SP
9
58.60
13 12 11 10
Completions
SANS/USANS
(Horizontal disks
Kcard_ss
10 mm diameter x 1 mm thick)
3 disks from: 1374.3 m
5 disks from: 1377.0 m
INTERVALS TO
SAMPLE/ANALYZE
CTS: 1364.3 – 1377.8 m
SLABBING: 1364.3 – 1377.8 m
SAND BLASTING: 1364.3 –
1377.8 m
PROBE K: 1364.3 – 1377.8 m
XRF: 1364.3 – 1377.8 m
6
6
CT Scans
CT Scans: Scout Scans
08-17-049-06W5
1364.3 m
Axial scan location
7
Mean porosity= 7.2%
1825
0.5
Mean porosity= 9.1%
Mean porosity= 8.6%
Density, kg/m3
Porosity
Mean porosity= 7.0%
Mean porosity= 6.5%
Mean porosity= 7.8%
2650
0
Mean porosity= 7.6%
Mean porosity= 7.7%
Mean porosity= 4.2%
8
CT Scans
CT Scans: Scout Scans
08-17-049-06W5
Axial scan location
1368.96 m
9
Density, kg/m3
Mean porosity= 13.6%
1825
Mean porosity= 10.0%
Porosity
Mean porosity= 12.4%
0.5
Mean porosity= 14.0%
Mean porosity= 10.0%
Mean porosity= 13.9%
Mean porosity= 21.7%
Mean porosity= 18.6%
10
2650
0
Mean porosity= 15.2%
10
CT Scans
CT Scans: Scout Scans
08-17-049-06W5
1374.59 m
Coreplugs
Axial scan location
11
Mean porosity= 8.6%
1825
0.5
Mean porosity= 8.0%
Mean porosity= 8.8%
Density, kg/m3
Porosity
Mean porosity= 9.9%
Mean porosity= 9.5%
Mean porosity= 9.0%
2650
0
Mean porosity= 9.9%
Mean porosity= 9.5%
Mean porosity= 10.4%
12
12
N2 Adsorption/Desorption
Isotherms
• Shape: qualitative assessment of pore structure
• Adsorption/desorption hysteresis:
– Type IV isotherms, mesoporous solids (2 nm < d < 50 nm)
– Shape of hysteresis loop can be indicative of pore
geometry
• Interpret isotherm data in terms of surface area (ex. BET
Theory) and pore size distributions (ex. BJH Theory)
15
N2 Adsorption/Desorption
Isotherms
6
CARDIUM
adsorption for all
samples except D2
• Substantial mesopore
volume
• Hysteresis loops may be
indicative of slit-shaped
pores
Quantity Adsorbed (cm 3/g)
• Similar amounts of
5
4
A2+A3
3
B2+B3
C3
2
D2
1
0
0
0.2
0.4
0.6
0.8
1
Relative Pressure (p/po )
16
N2 Adsorption/Desorption
6
15
BAKKEN
5
4
A2+A3
3
B2+B3
C3
2
D2
1
Quantity Adsorbed (cm 3/g)
Quantity Adsorbed (cm 3/g)
CARDIUM
10
BAK4
BAK5
5
BAK6
0
0
0
0.2
0.4
0.6
0.8
0
1
0.2
0.4
0.6
0.8
1
Relative Pressure (p/po )
Relative Pressure (p/po )
6
• More adsorption in Bakken, less in 2WS
• Differences in Hysteresis Loop Shape –
pore structure differences?
Quantity Adsorbed (cm 3/g)
2WS
5
4
3
2WS1
2WS12
2
2WS18
1
0
0
0.2
0.4
0.6
Relative Pressure (p/po )
0.8
1
17
N2 Adsorption/Desorption
BJH Analysis (PSD)
• Capillary condensation of
vapours in mesoporous
materials
• Uses Kelvin equation to
relate vapour pressure to
pore size
• Can use desorption
(convention) or adsorption
branch
• (Figure)
– Step AB: removal of
capillary condensate
Desorption analysis using BJH Theory
– Step BC: removal of
condensate from cores,
multi-layer thinning of
emptied (larger) pores
From SPE 147397
18
N2 Adsorption/Desorption
0.01
Desorption-CARDIUM
BJH Analysis (PSD)
size (peak ~ 200 – 350 A,
desorption)
• Artifact at ~ 35 A on
dV/dlog(w) (cm 3/g)
• Primarily unimodal pore
0.008
0.006
A2+A3
B2+B3
0.004
C3
D2
0.002
desorption curves
• Small pore size translates
0
10
into low permeability (later)
100
1000
Pore Width (Angstroms)
0.01
Adsorption -CARDIUM
dV/dlog(w) (cm 3/g)
0.008
0.006
A2+A3
B2+B3
0.004
C3
D2
0.002
0
10
100
Pore Width (Angstroms)
1000
19
N2 Adsorption/Desorption
0.02
0.01
Desorption-CARDIUM
0.016
0.006
A2+A3
B2+B3
0.004
C3
dV/dlog(w) (cm 3/g)
0.008
dV/dlog(w) (cm 3/g)
Desorption-BAKKEN
0.018
D2
0.002
0.014
0.012
0.01
BAK4
0.008
BAK5
0.006
BAK6
0.004
0.002
0
0
10
100
1000
10
Pore Width (Angstroms)
100
1000
Pore Width (Angstroms)
0.01
Desorption-2WS
• Cardium-Bakken, similar pore sizes, but
difference in volume
• 2WS – less mesoporosity
dV/dlog(w) (cm 3/g)
0.008
0.006
2WS1
0.004
2WS12
2WS18
0.002
0
10
100
Pore Width (Angstroms)
1000
20
N2 Adsorption/Desorption
0.02
0.01
Desorption-CARDIUM
0.006
A2+A3
B2+B3
0.004
C3
D2
0.002
Pore Volume (cm 3/g)
0.016
0.008
Pore Volume (cm 3/g)
Desorption-BAKKEN
0.018
0.014
0.012
0.01
BAK4
0.008
BAK5
0.006
BAK6
0.004
0.002
0
0
10
100
10
1000
100
1000
Pore Width (Angstroms)
Pore Width (Angstroms)
0.01
Desorption-2WS
• Cardium-Bakken, similar pore sizes, but
difference in volume
• 2WS – less mesoporosity
Pore Volume (cm 3/g)
0.008
0.006
2WS1
0.004
2WS12
2WS18
0.002
0
10
100
Pore Width (Angstroms)
1000
21
N2 Adsorption/Desorption
0.01
Desorption-CARDIUM
BJH Analysis (PSD)
tight gas reservoir
• Permeability implications
dV/dlog(w) (cm 3/g)
• Comparison to Montney
0.008
0.006
A2+A3
B2+B3
0.004
C3
D2
0.002
0
10
0.01
100
1000
Pore Width (Angstroms)
Desorption-POUCE COUPE
dV/dlog(w) (cm³/g)
0.008
0.006
S4
0.004
S5
S24
0.002
0
From Clarkson et al. AAPG Bulletin, in press
10
100
Pore Width (Angstroms)
1000
23
N2 Adsorption/Desorption
Relationship to
Permeability
• Can we relate pore structural
parameters to permeability
(dominant pore size, BET surface
area?)
• Currently gathering
permeability/porosity data for
Cardium so plot like the one on
the right (Montney TG) can be
developed
From Clarkson et al. AAPG Bulletin, in press
26
SANS/USANS
• In a SANS experiment, a neutron
beam is directed at a sample,
and the neutrons are elastically
scattered due to their interaction
with nuclei of atoms in the
sample
• The scattering vector is related to
a characteristic length scale (pore
size) in the sample
• SANS experiments, combined
From Melnichenko et al. (2009)
with USANS, also enable a wide
distribution of pore sizes (~ 0.3
nm to ~ 10 μm) to be investigated
27
SANS/USANS Analysis
28
SANS/USANS
• Similar scattering patterns
for all except:
– B1 and B2 exhibit a
“hump” at large Q, maybe
related to composition
• Higher scattering intensity
generally translates into
higher porosity
• Slope of linear portion of
curves (power-law
scattering) is close to -3
USANS
SANS
• For surface fractal geometry
(equivalent pore space is
uncorrelated spherical
pores), slope is -3 to -4
29
SANS/USANS
SANS/USANS
• Comparison to Montney
tight gas reservoir
• Montney has greater
slopes (-3.1 to -3.3)
30
SANS/USANS
SANS/USANS
1E+10
1E+9
1E+8
1E+7
f(R) (Å-1), SSA(r) (cm -1)
1E+6
I(Q) (cm-1)
1E+5
1E+4
1E+3
1E+2
1E+1
1E+0
1E-1
1E-2
1E-3
1E-4
1E-5
1E-4
1E-3
1E-2
1E-1
1E+0
1E+6
1E+5
1E+4
1E+3
1E+2
1E+1
1E+0
1E-1 1.0
1E-2
1E-3
1E-4
1E-5
1E-6
1E-7
1E-8
1E-9
1E-10
1E-11
1E-12
1E-13
1E-14
1E-15
1E-16
1E-17
1E-18
1E-19
1E-20
10.0
Q (Å-1)
100.0
1000.0
10000.0
100000.0
1000000.0
f(r)
SSA(r)(cm-1)
Power (f(r))
-3.9648
y = 27.69x
r (Å)
Fit of 1102A1 to PDSP model using PRINSAS
31
SANS/USANS
SANS/USANS
Sample
1102A1
1101A2
Exponent
-3
-3
Porosity(%)
5.17
7.18
Specific Surface Area (cm2/cm3)a
3.50e5
3.13e5
a: The probe size for SSA is 6.31Å
33
Future Work
• Gather profile permeability, XRF and additional pulsedecay permeability data
• Relate pore structural information to permeability
• Examine compositional and structural controls on porosity
and permeability
34