1. Evaluation of Betaine as Foam Booster Leyu Cui Presentation in Consortium Meeting, April 26 th 2011

2. Outline Characterization: Cocamidopropyl-betaine (CAB) and Lauryl-betaine (LB) Foam Evaluation: AOS, CAB and their blend Thermal Stability: CAB and LB

3. Outline Characterization: Cocamidopropyl-betaine (CAB) and Lauryl-betaine (LB) Foam Evaluation: AOS, CAB and their blend Thermal Stability: CAB and LB

4. Surfactants Structure AOS 16-18: Sodium alpha-olefin sulfonate, from Stepan Co. C n H 2n-1 -SO 3 Na (n=16-18) Cocamidopropyl-betaine (CAB): from Rhodia Co. R-CONH(CH 2 ) 3 -N + (CH 3 ) 2 CH 2 COO -, (R=C n H 2n+1, n=12-14) Lauryl-betaine (LB): from Rhodia Co. R-N + (CH 3 ) 2 CH 2 COO -, (R=C n H 2n+1, n=12)

5. Viscosities of Surfactant Solution Figure 1: The viscosities of Surfactant Solution. Total surfactant concentration is 0.2(wt)%, NaCl 3.5%, Na 2 CO 3 1.0% API: 41˚

6. Outline Characterization: Cocamidopropyl-betaine (CAB) and Lauryl-betaine (LB) Foam Evaluation: AOS, CAB and their blend Thermal Stability: CAB and LB

7. 1-D Foam Evaluation Setup Surfactant Alternating Gas (SAG) injection method, gas fraction f g = 2/3, surfactant slug size=0.1 PV, u=20 ft/day Figure 2: The schematic of 1-D setup Darcy’s Law:

8. CAB: Foam Booster rather than Foamer Figure 3: AOS, CAB and blend (0.2% total activity, ratio=1:1) foam evaluation in clean 20/40 mesh silica sandpack

9. AOS Foam Collapse with Oil 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

10. AOS Foam Flooding – Poor Sweep 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. 0.1 TPV 1.0 TPV 2.1 TPV 3.0 TPV

11. AOS/CAB Blend Foam Works with Oil 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 oil- free case.

12. 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

13. Possible Mechanisms for Good Sweep Efficiency of AOS/CAB blend Foam Stability: The Pseudo- emulsion film between oil drop and water-gas interface is stabilized by betaine. (Basheva, 2000) 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. (Lobo1 1993)

14. Outline Characterization: Cocamidopropyl-betaine (CAB) and Lauryl-betaine (LB) Foam Evaluation: AOS, CAB and their blend Thermal Stability: CAB and LB

15. HPLC-ELSD Setup to analyze surfactant Figure 8: HPLC-ELSD (evaporative light scattering detector) System HPLC Column: surfactant column

16. 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.

17. CAB aged for 40 hours and 8 days at 125 °C in 1% Na 2 CO 3 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.

18. Figure 11: The comparison of aged and unaged CAB in 1.0% Na 2 CO 3 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% Na 2 CO 3 brine Zoom in the Surfactant Peaks (1% Na 2 CO 3 )

19. 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.

20. 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

21. LB was aged for 24 days at 125 °C in 1.0% Na 2 CO 3 Figure 14: The comparison of aged and unaged LB in 1.0% Na 2 CO 3 brine in Full Scale. The salinity peaks are too large compared to the surfactant peaks.

22. Zoom in Small Peaks (1.0% Na 2 CO 3 ) Figure 15: The comparison of aged and unaged LB in 1.0% Na 2 CO 3 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% Na 2 CO 3 brine for 24 days.

23. 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.

24. 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.

25. Questions?

26. Backup Slides

27. 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;

28. Viscosity of Blends

29. AOS and CAB Foam in clean Sandpack Figure 3: AOS and CAB (0.2% activity) foam evaluation in clean 20/40 mesh silica sandpack.

30. Foam Evaluation with crude oil 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

31. Emulsion of AOS/LB

32. Sample Bottles and Pressure Vessel (a) (b) (c) 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.

33. 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.

34. CAB Aged in 3.5% NaCl--full Scale

35. CAB Aged in 3.5% NaCl--Zoom Scale

36. 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. Zoom in the Hydrophilic Components (1% Na 2 CO 3 )

37. 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.

38. 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.

39. 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.

40. 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.

41. 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.

42. 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.

43. 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.

44. 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.