Saleh K Al-Mansoori, Stefan Iglauer, Christopher H Pentland, Martin J Blunt
Three-Phase Measurements of Non-Wetting Phase Trapping Applied to Carbon
Dioxide Storage
2
Background
• Studied extensively to measure the amount of residual gas saturation during reservoir displacements.
• Suggested low oil saturations during gas displacement (oil layers).
• Trapping experience: experimentally on water-wet consolidated media.
• Pervious work:
• a linked the reduction of Sor to Sgt, a = 0 – 1, (a = 0 oil-wet, 0.45 - 0.75 water-wet)
• Showed:
Three-Phase Flow in Literature:
p3
gr
p2
or
p3
orSaSS
p2
or
p3
or SS
3
Motivation
• Principal interest: gas and oil trapping by water with application to CO2 storageUnconsolidated media
•Literature data for trapped gas saturation in consolidated systems.
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60 70 80 90 100
S(nw) i (%)
S(n
w)
r (%
)
Caubit et al., 2004 - 3ph Jerauld - 1996 - 3phMaloney et al., 2002 - 3ph Skauge et al., 2002 - 3ph, Sgi > 0.40Skauge et al., 2002 - 3ph, Sgi < 0.40 Kralik et al., 2000 - 3phKyte et al., 1956 - 3ph Holmgren et al., 1951, 3ph, OilFloodsHolmgren et al., 1951, 3ph, GasExpansion
4
Motivation
• Wide scatter in literature S(nw)i versus S(nw)r data.
•Trapping Capacity = S(nw)r
0
1
2
3
4
5
6
7
8
9
10
0 10 20 30 40 50 60 70 80 90 100
S(nw) i (%)
S
(nw
) r (%
)
Caubit et al., 2004 - 3ph Jerauld - 1996 - 3phMaloney et al., 2002 - 3ph Skauge et al., 2002 - 3ph, Sgi > 0.40Skauge et al., 2002 - 3ph, Sgi < 0.40 Kralik et al., 2000 - 3phKyte et al., 1956 - 3ph Holmgren et al., 1951, 3ph, OilFloodsHolmgren et al., 1951, 3ph, GasExpansion
5
Wetting phase – Brine (5wt% NaCl; 1wt% KCl)
Non-wetting phase – n-octane and air
Oil and brine rate= 5 mL/min (Ncap=10-5, 2x10-5)
Air injection rate = drainage gravity (different amounts of time)
Saturated air with octane for 5 hours
Controlled evaporation using long, narrow tube
Experimental Set Up
6
Oil-gas-brine experiments - Experimental Procedure
• Pack column with sand• Packing ratio used to give reproducible porosity
• Fully saturate column with brine (vertically)
• Fixed volume of brine and oil injected into the column (500 mL)
• Air enters from the top, oil and gas drain from bottom (gravity drainage)
• Column is left to drain for different amounts of time (17h, 2h, and 0.5h).
• Column is sliced for Sgi/Soi or waterflooded to reach Sgr/Sor.
• Column is sliced and sampled. Analysis of saturations in each section done with gas chromatography, GC & mass balance.• Thermal Conductivity Detector (TCD) allows water to be analysed
• Sand is carefully recovered and washed with de-ionized water, dry mass of sand is measured, weighed and measured VB each empty clean column section.
• Repeat (reproducibility)
7
Experimental Results: gravity drainage: 17 hour
0
20
40
60
80
100
0 20 40 60 80 100S(nw) i (%)
Dis
tan
ce
(c
m)
0
20
40
60
80
100
0 20 40 60 80 100S(nw) r (%)
Dis
tan
ce
(c
m)
Residuals: Sw/Sor/Sgr saturation curves– post
waterflooding
Initials: Swi/Soi/Sgi saturation curves
Results: Saturation profiles
8
Experimental Results: gravity drainage: 17 hour
Results: Trapping curves
a. Sgr Vs. Sgi
b. Sor Vs. Soi
c. Sor Vs. Sgi
d. Sor Vs. Sgr
e. Sgt Vs. Snr
f. Snr Vs. Sni
9
Experimental Results: gravity drainage: 2 hour
Results:
0
20
40
60
80
100
0 20 40 60 80
S(nw) i (%)
Dis
tan
ce
(c
m)
0
20
40
60
80
100
0 20 40 60 80 100S(nw) r (%)
Dis
tan
ce
(c
m)
Initials: Swi/Soi/Sgi saturation curves
Residuals: Sw/Sor/Sgr saturation curves– post
waterflooding
Results: Saturation profiles
10
Experimental Results: gravity drainage: 2 hour
Results:
a. Sgr Vs. Sgi
b. Sor Vs. Soi
c. Sor Vs. Sgi
d. Sor Vs. Sgr
e. Sgt Vs. Snr
f. Snr Vs. Sni
Results: Trapping curves
11
Experimental Results: gravity drainage: 0.5 hour
Results: Saturation profiles
0
20
40
60
80
100
0 20 40 60 80 100
S(nw) i (%)D
ista
nc
e (
cm
)
0
20
40
60
80
100
0 20 40 60 80 100
S(nw) r (%)
Dis
tac
e (
cm
)
Initials: Swi/Soi/Sgi saturation curves
Residuals: Sw/Sor/Sgr saturation curves– post
waterflooding
12
Experimental Results: gravity drainage: 0.5 hour
Results: Trapping curves
a. Sgr Vs. Sgi
b. Sor Vs. Soi
c. Sor Vs. Sgi
d. Sor Vs. Sgr
e. Sgt Vs. Snr
f. Snr Vs. Sni
13
Experimental Results: experiments 1-3
Results: Trapping curves
b. Compiled Sor vs. Soi
a. Compiled Sgr vs. Sgi
0
5
10
15
20
25
0 10 20 30 40 50 60 70 80 90 100
Sgi (%)
Sg
r (%
)
Sgr versus Sgi - 17 hrs
Sgr versus Sgi - 2 hrs
Sgr versus Sgi - 30 min
0
2
4
6
8
10
12
14
16
0 10 20 30 40 50 60 70 80 90 100
Soi (%)
So
r (%
)
Sor versus Soi - 17 hrs
Sor versus Soi - 2 hrs
Sor versus Soi - 30 min
14
Experimental Results – Comparison with Literature Data
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60 70 80 90 100
S(nw) i (%)
S(n
w)r
(%
)
Caubit et al., 2004 - 3ph Jerauld - 1996 - 3phMaloney et al., 2002 - 3ph Skauge et al., 2002 - 3ph, Sgi > 0.40Skauge et al., 2002 - 3ph, Sgi < 0.40 Kralik et al., 2000 - 3phKyte et al., 1956 - 3ph Jerauld - 1997 - 2ph - SgroJerauld - 1997 - 2ph - Sgrw Maloney et al., 2002 - 2ph - SgrwSkauge et al., 2002 - 2ph Kralik et al., 2000 - 2phCaubit et al., 2004 - 2ph - Sgrw Caubit et al., 2004 - 2ph - SgroOur results, 2008 - 3ph Our results, 2008 - 2ph - SorwOur results, 2008 - 2ph - Sgrw Holmgren et al., 1951, 3ph, OilFloodsHolmgren et al., 1951, 3ph, GasExpansion
15
Discussion and conclusions
For high initial gas saturation, more gas is trapped in the presence of oil than in two-phase flow.
The trapped oil saturation, while no higher than the maximum reached in two-phase flow, is higher than expected for low initial saturations.
Different from results in consolidated media.
Why? In unconsolidated media, in two-phase flow, there is little snap-off and hence little trapping.
In three-phase flow, oil layer collapse traps oil easily. Trapped oil prevents direct contact of gas by water except by snap-off and so we see more trapping.
Confirm this? Pore-scale modelling; further experiment at reservoir conditions and with consolidated media.
16
Acknowledgements
ADNOC
Shell-Imperial Grand Challenge on Clean Fossil Fuels
Thank you!