GC/MS Considerations for Fracking Gases and Water. Dr. Harold McNair Virginia Tech Blacksburg, VA.

Transcription

1 GC/MS Considerations for Fracking Gases and Water Dr. Harold McNair Virginia Tech Blacksburg, VA. 1

2 Outline What is fracking? Energy, Economics, Environmental Factors Chromatographic Considerations GC Conclusions 2

3 Fracking- HF 1. Hydraulic Fracking(HF) fractures rock formations, stimulating flow of oil and gas. Usually thousands of ft below the surface. 2. Large quantities of water, proppants (sand),cocktail of chemicals (benzene?) at high pressures pumped into the well. They fracture (open) the rock ,000 active HF wells in the USA, these wells generate 43% of oil and 67% of natural gas in US 3

4 Fracking- HF 1. Tons of water are used, 35% recycled 2. Gas and/or oil and 70% of water, and chemicals return to the surface. 3. Half of returned water re-injected. 4. Initially coal beds, later shale and today tight sands. 4

5 Schematic of HF well US world leader today (over 1,000,000 HF in US) Both gas and oil production HF major economic factor 5

6 HF-History first tried in PA. Dynamite used Seriously developed for methane from coal beds 3. HF responsible for 4%(2005) to 24%(2012) of US methane 4. Halliburton- 90% of On Shore oil and gas from HF wells 5. 4/2015-D.O.I. -all chemicals must be registered (FracFocus) 6

7 HF-History 1. Over 1 million HF wells in US, ~40k active today 2. Initially banned in France and UK. EU working on regulations at this time. 3. Today shale gas production major USA factor 4. Most recent tight sand formations require HF 7

8 Sources of Energy Coal, petroleum and natural gas 80% of worlds energy. All 3 in finite quantities, will need renewables. US Energy2014- oil 33%, coal 30%, gas 24% nuclear 4% Coal production decreasing! Unemployment? 8

9 Economic Goals of HF 1. Primarily generation of methane for energy. 2. Also recover C1,C2=,C3 for industrial use and possible export. 3. HF increased US oil and gas 67% in last 4 years 9

10 Economics Crude oil- $115-6/2014; $55-4/2015, two major factors- SUPPLY- Saudi Arabia (no decrease in production) INCREASE in US production (HF) US natural gas 50% cheaper than rest of world HF increased jobs and salaries (but for how long?) 10

11 Economics Strong incentive to ship cheaper US gas to Europe US export restrictions today, this may improve HF-US today 26% tight sandstone, 23% shale US imported 32% less gas,

12 Environmental Concerns Millions of gallons used/well 35% reused;70% to holding pond Need chemical analysis for toxic compounds (Benzene and Arsenic) Chromatography, AA, ICP 12

13 HF Potential Disadvantages 1. Jobs and higher salaries may be temporary. 2. Benzene is added to some cocktails 3. Toxic substances may be in back water 4. Can larger amounts of H2O be recycled? 5. Public wastewater treatment not permitted now 13

14 Chromatographic Challenges 1. Sampling usually in field, analysis in laboratory Both water and gas phase. 2. Should be simple, convenient, and GOOD DATA 3. Fast analysis ( /week) 5-8 minutes 4. Resolution separate air, CO2, and C1-C4 14

15 Chromatographic Challenges 5. LOD at least 1ppm with good precision 6. Detector MS or FID 7. Good calibration curves! 8. Portable, onsite GC useful 15

16 Sampling Devices 1) Plastic Syringe 2) Sampling bag 3) Vacutainers 4) Gas bomb 16

17 Sampling Kyle after one week in TN, 560 samples in vacutainers, gases and liquids Also gas bomb sampling

18 METHOD DEVELOPMENT Natural Gas Analysis ASTM Standard PLOT/Q Column, 30m long, 0.32mm ID, 20.0µm film TPGC 60 C, 2min; 30 C/min 240 C, hold 2 min

19 METHOD DEVELOPMENT Tracer Gas Analysis AL/Sulfate Column, 30m long, 0.25mm ID, 5.0µm film Isothermal Temperature 60 C

20 Chromatographic Conclusions 1. Sampling most critical step today both water and gas 2.Fast analysis ( /week) 5-8 minutes 3. LOD at least 1ppm with good accuracy (calibration curves) 4.Detector MS preferred 20

21 Growing Importance of HF Shale

22 Virginia Tech GC Equipment LEFT-Laboratory Gas Chromatograph and Mass Spectrometer Natural Gas and Tracer Samples RIGHT-Portable Field Gas Chromatograph Natural Gas Samples(only TCD)

23 ACKNOWLEDGEMENTS Dr. N. Ripepi, S. Jeter, Dr. K. Luxbacher, Dr. H. McNair, K. Louk 23