ADVANCEMENTS IN MICRO GAS CHROMATOGRAPHY (GC)

Transcription

1 ADVANCEMENTS IN MICRO GAS CHROMATOGRAPHY (GC) 1

2 Fast Analysis of C1 to C8 hydrocarbons for mud logging applications within 2 minutes using a temperature programmable Micro GC Fusion NEN GAS2015 Debbie Alcorn INFICON, Inc. 2 Technology Place East Syracuse, NY 13057, USA 2

3 Introduction Mud Logging Introduction Gas Sampling at the Well Site Gas Chromatography (GC) for Hydrocarbon Analysis Instrumentation Instrument Features Methods and Data C1-C5 in 34 seconds C1-C8 in 2 minutes On-Site Tips for Successful Analysis Future Development 3

4 Mud Logging Introduction Mud logging is the creation of reports of a borehole during active drilling A mud log provides geographical information, including (but not limited to): Lithology Rate of penetration Hydrocarbon content The concentration of C1-C8 compounds is critical Analysis must be performed on a continuous, 24-7 basis 4

5 Gas Sampling at the Well Site Mud is used to bring gas, formation fluids, and rock cuttings to the surface for analysis A gas trap separates the gas and liquid components The head space gas goes to the gas analyzer Gas chromatography (GC) is often used to analyze the gas sample 5

6 Gas Chromatography for Hydrocarbon Analysis GC has been used for mud logging for decades to characterize reservoir fluid composition Each reservoir is composed of different amounts of hydrocarbon species The ratios of compounds help identify zones of producible oil or gas 1 6

7 Gas Chromatography for Hydrocarbon Analysis Other calculations are used for wetness (W h ), balance (B h ), and character (C h ) 2 Example Interpretations: W h = C 2 + C 3 + ic 4 + nc 4 + C 5 C 1 + C C B h = C 1 + C 2 C 3 + ic 4 + nc 4 + C 5 C h = ic 4 + nc 4 + C 5 C 3 r o = gas density 7

8 Gas Chromatography for Hydrocarbon Analysis C1-C5 compounds are of main importance Analysis of heavier hydrocarbons is often desired Methylcyclohexane and C7 help indicate the presence of liquid phases 8

9 Instrumentation Small, transportable GC with MicroElectroMechanical Systems (MEMS) technology Successor to the 3000 Micro GC Gas only analysis MEMS Thermal Conductivity Detector (µtcd) Micro GC Fusion 9

10 Instrument Features Temperature programmable columns Minimizes carryover More compounds elute on a single column Increases sample throughput Resistively heated fused silica capillary columns 10

11 Instrument Features Micro GC utilizes a modular architecture Each module is its own GC: MEMs based injector Resistively heated fused silica capillary columns MEMs based µtcd 11

12 Instrument Features Micro GC Fusion utilizes a new User Interface (UI) Front panel display Direct Ethernet connection to a computer Direct Ethernet connection to a LAN hub for remote access Wi-Fi enabled License free Works with any platform (ex. Windows, Apple, Android) 12

13 Instrument Features Integrated sample conditioner (optional) Reduces sample pressures from up to 1000 psi down to ~ 5 psi (~34 kpa) Filters out particulates Heats the sample to 100 ºC Maintains sample temperature to prevent condensation 13

14 Isothermal Method C1-C5 2 module system Module A 8m RT-Q-Bond, variable volume injector Module B 10m Rxi-1ms, variable volume injector A method was designed to run continuously, using isothermal operation Total cycle time was 34 seconds 14

15 Calibration Standard Component Amount (%) Nitrogen Methane Ethane Propane ic nc ic nc

16 Chromatograms Module A: RT-Q-Bond Initial parameters used: 55 C, 37 psi (255 kpa), 15 ms injection time, 5 second pump, Helium carrier gas 16

17 Chromatograms Module B: Rxi-1ms Initial parameters used: 90 C, 33 psi (227 kpa), 15 ms injection time, 5 second pump, Helium carrier gas 17

18 Repeatability Exceptional repeatability Less than 0.1 %RSD for retention time Less than 0.6 %RSD for area 1/29/2014 Last 10 runs (10:09 a.m. to 10:16 a.m.) Area %RSD RT %RSD Nitrogen Methane Ethane Propane ic nc ic nc

19 10 Runs Overlaid RT-Q-Bond 19

20 10 Runs Overlaid Rxi-1ms 20

21 500 ppm Methane Module A: RT-Q-Bond - 37 psi (255 kpa) and 32 psi (220 kpa) Syringe dilution Reported concentration 0.051% 21

22 100 ppm Methane Module A: RT-Q-Bond - 37 psi (255 kpa) and 32 psi (220 kpa) Syringe dilution Reported concentration 0.014% 22

23 Temperature Ramped Method C1-C8 2 module system Module A 8m RT-Q-Bond, variable volume injector Module B 10m Rxi-1ms, variable volume injector A method was designed to run continuously, using temperature programming Total cycle time was approximately 2 minutes 23

24 Extended Calibration Standard Component Amount (%) Nitrogen Methane 0.5 CO Ethylene Ethane 0.2 Propylene Propane ic nc ic nc Component Amount (%) nc Benzene Cyclohexane nc Methylcyclohexane 0.01 Toluene nc

25 Chromatograms Module A: RT-Q-Bond 55 C(15s hold) 220 C(10s hold) 7 C/s, 35 psi (241 kpa), 30 ms injection time, Helium carrier gas 25

26 Chromatograms Module B: Rxi-1ms 75 C(9s hold) 220 C(12s hold) 7 C/s, 33 psi (227 kpa), 80ms injection time, Helium carrier gas 26

27 On-Site Tips for Successful Analysis Power Access to stable power Surge protector, UPS Heated transfer lines To keep heavier hydrocarbons from condensing Gas trap stability Water traps, filters 27

28 Challenges Method was optimized for speed Aggressive ramp Not optimized for instrument stability Carryover effect Without a backflush injector, heavier compounds can stick to the columns Peaks elute during subsequent runs 28

29 Future Method Developments Future method developments will include: Backflush injectors to prevent carryover Different combination of columns types/lengths Faster analysis with a less aggressive ramp Analysis of ethylbenzene, nc9 with the same cycle time 29

30 Conclusion Using isothermal operation, C1-C5 compounds can be analyzed within 34 seconds with excellent repeatability Using temperature programming, C1-C8 compounds can be analyzed within 2 minute cycle time Additional compounds, such as CO 2, ethylene, and propylene were also analyzed Future method developments will focus on: Optimizing the configuration of Micro GC Fusion Optimizing the corresponding methods 30

31 References 1. B.O. Pixler, Journal of Petroleum Technology, Vol 21, Number 6, 1969, pag J.H. Haworth, Interpretation of Hydrocarbon Shows Using Light (C1-C5) Hydrocarbon Gases from Mud-Log Data, The American Association of Petroleum Geologist Bulletin, Vol 69, Number 8, 1985, pag P. Ablard, D. Cook, K. Fielding, G. Haines, M. Herkommer, K. McCarthy, M. Radakovic, L. Umar, The Expanding Role of Mud Logging, Oilfield Review, Vol 24, Number 1, 2012, pag SPE International. Formation Evaluation During Mud logging. (accessed March ). 31

32 For more information, visit: Or Booth #7 32

33 Questions? 33