1. SPME Coupled with GC- FID for the Detection of n-Propyl Alcohol and Its Use as a Geothermal Tracer Michael Mella 1,2 1 Energy and Geoscience Institute - University of Utah, 2 Chemical Engineering Department – University of Utah Senior Projects Lab I - 2006

2. Why n-propanol? Liquid phase only tracers and vapor phase only tracers are in common use Liquid phase only tracers and vapor phase only tracers are in common use Two-phase tracers are needed to better trace water Two-phase tracers are needed to better trace water n-Propanol has a similar partition coefficient to water, similar two-phase characteristics to water n-Propanol has a similar partition coefficient to water, similar two-phase characteristics to water

3. Objectives Lab work - Develop an analytical method to reduce the limit of detection of n-propanol Lab work - Develop an analytical method to reduce the limit of detection of n-propanol Field work - Validate method with a field test Field work - Validate method with a field test

4. Lab Development Solid Phase MicroExtraction (SPME) was used to help lower the limit of detection over previous methods by 30 fold Solid Phase MicroExtraction (SPME) was used to help lower the limit of detection over previous methods by 30 fold Gas Chromatography with a Flame Ionization Detector used to analyze n- propanol solutions Gas Chromatography with a Flame Ionization Detector used to analyze n- propanol solutions

5. SPME basics A flexible fiber coated with 85µm thick A flexible fiber coated with 85µm thick Carboxen/PDMS layer A needle that houses the fiber and an injection assembly A needle that houses the fiber and an injection assembly

8. GC analysis Needle injected into 300°C GC inlet Needle injected into 300°C GC inlet Separation by HP-5 capillary column Separation by HP-5 capillary column Detection by FID Detection by FID Analysis of signal using HP-CHEM software Analysis of signal using HP-CHEM software

12. Analytical method results Limit of detection at 1 ppb Limit of detection at 1 ppb Reduction by a factor of 30 from previous methods Reduction by a factor of 30 from previous methods Lower limit of detection means less n- propanol needed for test Lower limit of detection means less n- propanol needed for test Method can be extended to other alcohols and aldehydes Method can be extended to other alcohols and aldehydes

13. Objectives Lab work - Develop an analytical method to reduce the limit of detection of n-propanol Lab work - Develop an analytical method to reduce the limit of detection of n-propanol Field work - Validate method with a field test Field work - Validate method with a field test

14. Field test Injector 34-9RD2 of Coso East Flank tagged with 165 gallons n-propanol Injector 34-9RD2 of Coso East Flank tagged with 165 gallons n-propanol Samples taken from surrounding East Flank producers Samples taken from surrounding East Flank producers

15. Field Work Alcohol returns Alcohol returns Comparison with a liquid tracer test Comparison with a liquid tracer test

17. Alcohol returns Raw results Raw results E(t) scaled results and recovery E(t) scaled results and recovery Liquid phase tracer results Liquid phase tracer results

20. Alcohol returns Raw results Raw results E(t) scaled results and recovery E(t) scaled results and recovery Liquid phase tracer results Liquid phase tracer results

21. E(t) E(t) residence-time distribution function E(t) residence-time distribution function E(t) is a way to normalize for mass of tracer injected and flow rates E(t) is a way to normalize for mass of tracer injected and flow rates E(t) required for future assessment of return data, an example is the convolution integral and tracer recovery E(t) required for future assessment of return data, an example is the convolution integral and tracer recovery

22. Tracer Recovery Use E(t) to calculate the amount of tracer recovered in both the liquid phase and the vapor phase. Use E(t) to calculate the amount of tracer recovered in both the liquid phase and the vapor phase.

24. Alcohol returns Raw results Raw results E(t) scaled results and recovery E(t) scaled results and recovery Liquid phase tracer return Liquid phase tracer return

25. Liquid phase tracer return 2 months prior 100 kg 1,3,5-NTS injected into 34-9RD2 2 months prior 100 kg 1,3,5-NTS injected into 34-9RD2 Samples from the same area were taken and analyzed by HPLC with a fluorescence detector Samples from the same area were taken and analyzed by HPLC with a fluorescence detector

27. Return comparisons Normalized n-propanol and 1,3,5-NTS return curves were plotted together with a common x-axis of days after their respective injection date. Normalized n-propanol and 1,3,5-NTS return curves were plotted together with a common x-axis of days after their respective injection date.

29. Return comparisons Tracer recovery of n-propanol = 3.5% Tracer recovery of n-propanol = 3.5% Tracer recover of 1,3,5-NTS = 74.8% Tracer recover of 1,3,5-NTS = 74.8%

30. Conclusions Similar arrival times for 1,3,5-NTS and n-propanol in well 38C-9 Similar arrival times for 1,3,5-NTS and n-propanol in well 38C-9 Appearance of n-propanol in 38D-9 but not 1,3,5-NTS Appearance of n-propanol in 38D-9 but not 1,3,5-NTS 38B-9 seems to have been “skipped” by both tracers 38B-9 seems to have been “skipped” by both tracers Less return of n-propanol than of 1,3,5-NTS Less return of n-propanol than of 1,3,5-NTS

32. Conclusions Similar arrival times for 1,3,5-NTS and n-propanol in well 38C-9 Similar arrival times for 1,3,5-NTS and n-propanol in well 38C-9 Appearance of n-propanol in 38D- 9 but not 1,3,5-NTS Appearance of n-propanol in 38D- 9 but not 1,3,5-NTS 38B-9 seems to have been “skipped” by both tracers 38B-9 seems to have been “skipped” by both tracers Less return of n-propanol than of 1,3,5-NTS Less return of n-propanol than of 1,3,5-NTS

34. Conclusions Similar arrival times for 1,3,5-NTS and n-propanol in well 38C-9 Similar arrival times for 1,3,5-NTS and n-propanol in well 38C-9 Appearance of n-propanol in 38D-9 but not 1,3,5-NTS Appearance of n-propanol in 38D-9 but not 1,3,5-NTS 38B-9 seems to have been “skipped” by both tracers 38B-9 seems to have been “skipped” by both tracers Less return of n-propanol than of 1,3,5-NTS Less return of n-propanol than of 1,3,5-NTS

36. Conclusions Similar arrival times for 1,3,5-NTS and n-propanol in well 38C-9 Similar arrival times for 1,3,5-NTS and n-propanol in well 38C-9 Appearance of n-propanol in 38D-9 but not 1,3,5-NTS Appearance of n-propanol in 38D-9 but not 1,3,5-NTS 38B-9 seems to have been “skipped” by both tracers 38B-9 seems to have been “skipped” by both tracers Less return of n-propanol than of 1,3,5-NTS Less return of n-propanol than of 1,3,5-NTS

38. Conclusion Lab work - n-propanol is appropriate as a geothermal tracer in smaller volume by using SPME-GC-FID Lab work - n-propanol is appropriate as a geothermal tracer in smaller volume by using SPME-GC-FID Lab work - Alcohols can be a powerful tool in determining two-phase pathways in reservoirs Lab work - Alcohols can be a powerful tool in determining two-phase pathways in reservoirs

39. Acknowledgements This work was supported by grants from the Department of Energy. Done with the support of Coso Operating Company, LLC; and the Geothermal Program Office of the Naval Air Weapons Station.

40. Acknowledgements Peter Rose 1, Nick Dahdah 1, Michael Adams 1, Jess McCulloch 2, Cliff Buck 2, and G. Michael Shook 3 1 Energy and Geoscience Institute – University of Utah 2 Coso Operating Company – Catihness Energy LLC 3 Idaho National Laboratory

41. References Adams, M.C., Yamada, Y., Yagi, M., Kondo, T., and Wada, T. (2000), “Stability of Methanol, Propanol, and SF 6 as High-Temperature Tracers,” World Geothermal Congress p. 3015-3019 Adams, M.C., Yamada, Y., Yagi, M., Kasteler, C., Kilbourn, P., and Dahdah, N. (2004), “Alcohols as Two-Phase Tracers,” Proceedings, Twenty-Ninth Workshop on Geothermal Reservoir Engineering Fogler, H.S. Elements of Chemical Reaction Engineering. 3 rd Edition, New Jersey: Prentice Hall, 1999, chapter 13. Fukuda, D., Asanuma, M., Hishi, Y., Kotanaka, K. (2005), “Alcohol Tracer Testing at the Matsukawa Vapor-Dominated Geothermal Field, Northeast Japan,” Proceedings, Thirtieth Workshop on Geothermal Reservoir Engineering Fukuda, D., Asanuma, M., Hishi, Y., Kotanaka, K. (2005), “Alcohol Tracer Testing at the Matsukawa Vapor-Dominated Geothermal Field, Northeast Japan,” Proceedings, Thirtieth Workshop on Geothermal Reservoir Engineering

42. References Mella, M.J., Rose, P.E., McCulloch, J., Buck, C., Adams, M.C., Dahdah, N.F. (2006), “The Use of n-Propanol as a Tracer at the site of the Coso Engineered Geothermal System,” PROCEEDINGS, Thirty-First Workshop on Geothermal Reservoir Engineering Stanford University,SGP-TR-179 Stanford University,SGP-TR-179 Rose, P.E., Mella, M.J., Kasteler, C. (2003), “ Rose, P.E., Mella, M.J., Kasteler, C. (2003), “A New Tracer For Use in Liquid-Dominated, High-Temperature Geothermal Reservoirs,” GRC Transactions, 27, pp. 403-406 Supelco (2003), Chromatography Products for analysis and Purification. Supelco p. 348-358

43. Questions?