Evaluation of Betaine as Foam
Booster
Leyu Cui
Presentation in Consortium
Meeting, April 26th 2011
Outline
• Characterization: Cocamidopropyl-betaine
(CAB) and Lauryl-betaine (LB)
• Foam Evaluation: AOS, CAB and their blend
• Thermal Stability: CAB and LB
Outline
• Characterization: Cocamidopropyl-betaine
(CAB) and Lauryl-betaine (LB)
• Foam Evaluation: AOS, CAB and their blend
• Thermal Stability: CAB and LB
Surfactants Structure
• AOS 16-18: Sodium alpha-olefin sulfonate,
from Stepan Co.
CnH2n-1-SO3Na (n=16-18)
• Cocamidopropyl-betaine (CAB): from
Rhodia Co.
R-CONH(CH2)3-N+(CH3)2CH2COO-,
(R=CnH2n+1, n=12-14)
• Lauryl-betaine (LB): from Rhodia Co.
R-N+(CH3)2CH2COO-,
(R=CnH2n+1, n=12)
Viscosities of Surfactant Solution
Viscosity / cp
12
10
AOS:CAB=1:1
Crude Oil
AOS:LB=4:1
CAB
AOS 16-18
Lauryl Betaine
8
API: 41˚
6
4
2
0
0
100
200
300
Shear rate / 1/s
400
Figure 1: The viscosities of Surfactant Solution. Total surfactant concentration is
0.2(wt)%, NaCl 3.5%, Na2CO3 1.0%
Outline
• Characterization: Cocamidopropyl-betaine
(CAB) and Lauryl-betaine (LB)
• Foam Evaluation: AOS, CAB and their blend
• Thermal Stability: CAB and LB
1-D Foam Evaluation Setup
Surfactant Alternating Gas (SAG) injection method, gas
fraction fg = 2/3, surfactant slug size=0.1 PV, u=20 ft/day
Darcy’s Law:
u  
Figure 2: The schematic of 1-D setup
k


Apparent viscosity/ cp
CAB: Foam Booster rather than Foamer
AOS-CAB blend
AOS only
CAB only
1000
100
10
1
0
0.5
1
1.5
2
2.5
3
TPV
Figure 3: AOS, CAB and blend (0.2% total activity, ratio=1:1) foam evaluation in clean
20/40 mesh silica sandpack
AOS Foam Collapse with Oil
Apparent Viscosity / cp
1000
AOS in the absence of oil
AOS in the presence of oil
100
10
1
0
1
2
TPV
3
4
Figure 4: AOS 16-18 (0.2% activity) foam evaluation in the presence of crude oil.
AOS lost its mobility control in the presence of oil
AOS Foam Flooding – Poor Sweep
0.1 TPV
1.0 TPV
2.1 TPV
3.0 TPV
Figure 5: the pictures of the AOS 16-18 foam flooding sandpack, which shows there is
still lots of residual oil in the sandpack. AOS foam doesn’t have good mobility
control in the presence of oil.
AOS/CAB Blend Foam Works with Oil
Apparent Viscosity / cp
1000
100
10
AOS-CAB in the absence of oil
AOS-CAB in the presence of oil
1
0
1
2
TPV
3
4
5
6
Figure 6: AOS-CAB blend(0.2% activity) foam evaluation in the presence of crude oil.
Blend still has good foaming ability in the presence of oil, but not as good as in oilfree case.
AOS/CAB blend Foam Flooding
Figure 7: the pictures of AOS-CAB blend foam flooding sandpack, which shows the
blend has a good oil-sweeping ability even in the presence of oil
Possible Mechanisms for Good Sweep
Efficiency of AOS/CAB blend
• Foam Stability: The Pseudoemulsion film between oil drop
and water-gas interface is
stabilized by betaine. (Basheva, 2000)
(Lobo1 1993)
Viscosity / cp
• The viscosity of the blend (8.33
cp) is much higher than crude
oil (3.89 cp). So, a favorable
mobility ratio can be reached.
15
AOS:CAB=1:1
Crude Oil
10
5
0
0
200
400
Outline
• Characterization: Cocamidopropyl-betaine
(CAB) and Lauryl-betaine (LB)
• Foam Evaluation: AOS, CAB and their blend
• Thermal Stability: CAB and LB
HPLC-ELSD Setup to analyze surfactant
HPLC Column: surfactant column
Figure 8: HPLC-ELSD (evaporative light scattering detector) System
CAB was aged for 10 days at 125 °C in
DI water
Figure 9: the comparison of HPLC signal for unaged and aged CAB in DI water. They
are exactly the same at characteristic peak. So, CAB is stable at 125 C in DI water for
10 days.
CAB aged for 40 hours and 8 days at
125 °C in 1% Na2CO3 brine
Figure 10: The comparison of aged and unaged CAB in 1.0% Na2CO3 brine in Full
Scale. The salinity peaks are too large compared to the surfactant peaks.
Zoom in the Surfactant Peaks (1% Na2CO3)
Figure 11: The comparison of aged and unaged CAB in 1.0% Na2CO3 brine in Zoom
Scale. The characteristic peak (at 16.5 min) for aged sample is much smaller than
unaged sample. So, the CAB is not stable at 125 C in 1.0% Na2CO3 brine
CAB aged for 3 & 8 days at 125 °C in
pH=3.19 buffer
Figure 12: The comparison of aged and unaged CAB in pH=3.19 buffer (ammonium
acetate – acetic acid ) in full scale. The characteristic peak is at 16.5 min.
Zoom in Surfactant Peaks (pH=3.19)
Figure 13: The comparison of aged and unaged CAB in pH=3.19 buffer (ammonium
acetate – acetic acid ) in zoom scale. The characteristic peak is at 16.5 min. The peaks
of aged samples are much lower than unaged one, which means CAB is not stable in
pH=3.19 buffer at 125C
LB was aged for 24 days at 125 °C in
1.0% Na2CO3
Figure 14: The comparison of aged and unaged LB in 1.0% Na2CO3 brine in Full Scale.
The salinity peaks are too large compared to the surfactant peaks.
Zoom in Small Peaks (1.0% Na2CO3)
Figure 15: The comparison of aged and unaged LB in 1.0% Na2CO3 brine in Zoom
Scale. The characteristic peaks (at 6.5 & 10.5 min) are the same. So, the LB is stable
at 125 ˚C in 1.0% Na2CO3 brine for 24 days.
LB aged at 125 ˚C in pH=3.36 buffer
Figure 16: the comparison of HPLC signal for unaged and aged LB in pH=3.36 buffer.
They are exactly the same at characteristic peak. So, LB is stable at 125 ˚C in pH=3.36
buffer solution for 24 days.
Conclusion
• The cocamidopropyl-betaine (CAB) is a very good foam
booster, but not a good foamer. The blend of AOS 16-18
and CAB can tolerate crude oil and shows good mobility
control in tertiary oil recovery process.
• The thermal stability of CAB is a problem, especially in
high and low pH solution (pH dependence) at high
temperature (125 °C). But LB is relative stable at high
temperature.
Questions?
Backup Slides
Properties of SME Oil
• Viscosity is 3.89 cp, API=41.1˚
• The Total Acid Number (TAN) is 0.127±0.015
mg KOH/ (g oil)
• Soap Number is 0.0226±0.0022 mg KOH/ (g
oil) with IPA and 0.0104±0.0018 mg KOH/ (g
oil) without IPA;
Viscosity of Blends
AOS and CAB Foam in clean Sandpack
AOS only
Foam Apparent viscosity
1000
CAB only
WAG
100
10
1
0
0.5
1
1.5
2
2.5
3
TPV
Figure 3: AOS and CAB (0.2% activity) foam evaluation in clean 20/40 mesh silica
sandpack.
Foam Evaluation with crude oil
Apparent Viscosity / cp
1000
100
10
AOS in the presence of oil
AOS in the absence of oil
WAG
1
0.1
0
1
TPV
2
3
4
Figure 8: AOS 16-18 (0.2% activity) foam evaluation in the presence of
crude oil. AOS lost its foaming ability in the presence of oil
Emulsion of AOS/LB
Sample Bottles and Pressure Vessel
(a)
(b)
Figure 9: (a) the sample bottle for surfactant aged
at 125 °C (b) if the bottle was fully filled by liquid,
the pressure inside and outside bottle can be
balanced through the red rubber pad at the
center of the lid. (c) high pressure vessel: the
inside pressure is upto 50 psig to prevent the
liquid boiling.
(c)
One CAB Sample was Tested Twice
Figure 11: ELSD signals of 0.1% (activity) CAB in DI water. Both lines are for the same
sample, the shift of the signal is due to the system error of HPLC. The characteristic
peak is at 5.25 min.
CAB Aged in 3.5% NaCl--full Scale
CAB Aged in 3.5% NaCl--Zoom Scale
Zoom in the Hydrophilic Components
(1% Na2CO3)
Figure 15: The comparison of aged and unaged samples in 1.0% Na2CO3 brine in
Zoom Scale. Aged samples have more peaks around 3-4 mins, which means CAB can
be degraded into very hydrophilic molecular at 125 C.
CAB aged at 125 °C in pH=4.47 buffer
Figure 16: The comparison of aged and unaged CAB in pH=4.47 buffer (ammonium
acetic – acetic acid ) in full scale. The characteristic peak is at 16.5 min.
Zoom in Surfactant Peaks (pH=4.47)
Figure 17: The comparison of aged and unaged CAB in pH=4.47 buffer (ammonium
acetate – acetic acid ) in zoom scale. The characteristic peak is at 16.5 min. The peaks
decrease very slowly with the aging time.
Zoom in Hydrophilic Components
(pH=4.47)
Figure 18: The comparison of aged and unaged CAB in pH=4.47 buffer (ammonium
acetate – acetic acid ) in zoom scale. The salinity peaks of aged samples are little
higher than unaged one, which means CAB is degrade into very hydrophilic
molecular.
CAB aged at 125 C in pH=4.47 buffer
Red line: unaged sample
Blue line: aged for 3days
Green line: aged for 8days
Figure 22 The comparison of aged and unaged CAB in pH=4.47 buffer
(ammonium acetate – acetic acid ) in zoom scale. The salinity peaks of aged
samples are little higher than unaged one, which means CAB is degrade into
very hydrophilic molecular.
Zoom in Hydrophilic Components
(pH=3.19)
Figure 21: The comparison of aged and unaged CAB in pH=3.19 buffer (ammonium
acetate – acetic acid ) in zoom scale. The salinity peaks of aged samples are much
higher than unaged one, which means CAB is degrade into very hydrophilic
molecular.
CAB aged at 125 C in pH=3.19 buffer
Blue line: unaged sample
Red line: aged for 3days
Green line: aged for 8days
Figure 25 The comparison of aged and unaged CAB in pH=3.19 buffer
(ammonium acetate – acetic acid ) in zoom scale. The salinity peaks of aged
samples are much higher than unaged one, which means CAB is degrade into
very hydrophilic molecular.
LB was aged for 24 days at 125 °C in
DI water
Figure 22: the comparison of HPLC signal for unaged and aged LB in DI water. They
are exactly the same at characteristic peak. So, LB is stable at 125 C in DI water for 24
days.
LB aged at 125 ˚C in pH=4.0 buffer
Figure 25: the comparison of HPLC signal for unaged and aged LB in pH=4.0 buffer.
They are exactly the same at characteristic peak. So, LB is stable at 125 C in pH=4.0
buffer solution for 24 days.