Handheld Laser-Based Methane Leak Detection Device Performance During Controlled Natural Gas Releases

Rachel Day, Ezra Levin, Dan Zimmerle

CSU Energy Institute, Colorado State University

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Background


Overview

Operators at oil and gas facilities have been performing methane leak detection and repair methods to find, locate and fix fugitive, or unknown emissions. Most operators perform site inspections and verify leak repair using optical gas imaging (OGI) cameras or Method 21 techniques.

  • EPA has included a pathway for the use of advanced methane detection technologies in recognition of the rapid and continuous advancement of these technologies. 
  • Examples of these technologies are:
    • Aerial flyovers using remote sensing technology
    • Unmanned aerial systems
    • On-site sensor networks
    • Sentinel camera systems
    • Ground-based mobile monitoring
    • Satellite Detection and Retrieval
  • These technologies are to be used as an alternative to ground-based OGI surveys, EPA Method 21, and AVO inspections to identify emissions from well sites, centralized production facilities, and compressor stations.
    • Periodic Screening Framework (i.e., matrix)
    • Continuous Monitoring Approach
To people stand by equipment at the METEC site. One is holding a handheld laser.
Figure 1: Testing handheld lasers at METEC tanks 

Periodic Screening

  • The final rules provide greater flexibility
  • Frequency will be based on the technology with the highest aggregate detection threshold
  • Final rule also allows owner(s) or operator(s) to replace any periodic screening survey with an OGI survey.

Table 1 to subpart OOOOb of Part 60

Alternative Technology Periodic Screening Frequency at Well Sites, Centralized Production Facilities, and Compressor Stations Subject to AVO Inspections with Quarterly OGI or EPA Method 21 Monitoring
Minimum Screening FrequencyMinimum Detection Threshold of Screening Technology
Quarterly≤1 kg/hr*
Bimonthly≤2 kg/hr
Bimonthly + OGI≤10 kg/hr
Monthly≤5 kg/hr
Monthly + OGI≤15 kg/hr
*3 kg/hr for a periods of 2-years from effective date of the rule.

Table 2 to subpart OOOOb of Part 60

Alternative Technology Periodic Screening Frequency at Well Sites and Centralized Production Facilities Subject to AVO Inspections and/or Semiannual OGI or EPA Method 21 Monitoring
Minimum Screening FrequencyMinimum Detection Threshold of Screening Technology
Semiannual≤1 kg/hr
Triannual≤2 kg/hr
Triannual + OGI≤10 kg/hr
Quarterly≤5 kg/hr
Quarterly + OGI≤15 kg/hr
Bimonthly≤15 kg/hr

The US EPA has introduced processes that allow advanced methods for methane leak detection to be certified as Alternative Testing Methods to replace some aspects of required screenings under The Final Rule. This study can provide insight towards their use with periodic screenings and repair verification.


Methodology

CSU’s METEC study team joined with Devon Energy:

  • 279 natural gas releases
  • 30 surveyors
  • 10 operators
  • 4 handheld laser devices
  • 20 days testing at METEC

Table shows example of surveyors’ documentation

Scanner Name
Recorder Name
Instrument Make/Model
Instrument Serial #
Release IDEquipment GroupDateScanner Start Time (MT)Scanner End Time (MT)Max Concentration (ppm-m)Max COnc TimeEmission Location Estimate
14S-34/24/20259:189:25469:19Flange on kimray
24S-54/24/20259:189:253579:22Glass site
34S-14/24/20259:189:252049:24Level controller
Surveyor scanning separators
Figure 2: Surveyor scanning separators
Figure 3: Devices used in this study: Sensit GasTrac LZ 30, Heath RMLD-CS, Ecotec GazoScan, and Pergam Laser Methane Smart
surveyor movement at METEC
Figure 4: Table shows example of surveyors’ documentation, and the image shows the surveyor movement at METEC during a complete round of testing

Results

Results are preliminary at this point, as the study is still underway. Results of detection classification at the component level show all devices detecting leaks much more than when they miss them and/or localize them to an inaccurate component. This is seen when fugitive emissions have and do not have baseline emissions also occurring.

Component Detection Classification by Device, with Fugitive Emissions for Device A, B, C, and D and Baseline + Fugitive Emissions for Device A and C.
Figure 5: Leak detection classification on a component level. Left plot shows results when test releases simulated continuous fugitive leaks. Right plot shows when test releases included continuous fugitives and simulated intermittent and continuous baseline emissions.

The devices that participated in the baseline testing performed better than when there were only fugitive emissions occurring. Part of this could be due to the release configuration at METEC, as only one fugitive emission per equipment unit can be occurring while the baseline emissions are running. During the fugitive testing, multiple emissions can be occurring on the same equipment unit, possibly making detection more challenging. Although handheld laser-based devices are new, surveyors’ experience does not seem to weigh on detection results.

Leak detection classification on a component level
Figure 6: Leak detection classification on a component level. Left plot shows overall testing results. Right plot shows the overall results broken down into the surveyors' previous experience with handheld laser-based devices.

Preliminary lower detection limit results show all the devices performing with limits below 0.6 kg/hr. Based on the EPA’s Alternative Testing Method (ATM) parameters all these devices are applicable to become ATMs with required periodic screenings of facilities on a semiannual frequency. That frequency would be quarterly for compressor stations.

Probability of Detection on the y axis broken out by device A, B, C, and D with METEC Release Rate (slpm) on the x-axis.
Figure 7: 90% probability of detection limit and power curve

Conclusions and Next Steps

As testing is concluding, the METEC team is focusing on meeting the objectives of the study as set between CSU and Devon Energy, including:

    • Finalizing the device threshold for ATM application
    • Finalizing usage procedure/protocol for data production
    • Finalizing study analysis to include:
      • Weather and wind conditions
      • Release point configuration
      • Repair and maintenance verification

Performance parameters will be finalized and analyzed for controlled environment testing on the devices. This is applied to all devices as a standard to be conducted initially for each device.

See caption
Figure 8: Gas reference cell for parameter standard testing

This study concluded that the main function of the devices would be for verification of repair and maintenance at oil and gas facilities. There was a general opinion from surveyors that these devices function best for detection per equipment unit, and not for large scale field scans.

See caption
Figure 9: Surveyors during study at METEC

Acknowledgments and Contact Information

Thank you to Devon Energy for facilitating this project and providing operators to visit METEC for testing. Thank you to the operators who provided surveyors for this study, including Antero, ConocoPhillips, Continental Resources, Coterra, Devon, Energy Transfer, Expand, ExxonMobil, Ovintiv, and Scout. Thank you to the EPA for providing insight and knowledge around Alternative Testing Methods. Thank you to the handheld laser-based device developers for being involved in
this testing and providing use of their devices.

Rachel Day | Research Associate | CSU Energy Institute, Colorado State University | [email protected]

A group stands in front of some equipment at METEC.

References

Oil and Gas Alternative Test Methods | US EPA

Kwaśny, M.; Bombalska, A. Optical Methods of Methane Detection. Sensors 2023, 23 (5), 2834. https://doi.org/10.3390/s23052834.

Zhang, E. J.; Teng, C. C.; Van Kessel, T. G.; Klein, L.; Muralidhar, R.; Wysocki, G.; Green, W. M. J. Field Deployment of a Portable Optical Spectrometer for Methane Fugitive Emissions Monitoring on Oil and Gas Well Pads. Sensors 2019, 19 (12), 2707. https://doi.org/10.3390/s19122707.

Sorg, D. Measuring Livestock CH4 Emissions with the Laser Methane Detector: A Review. Methane 2021, 1 (1), 38–57. https://doi.org/10.3390/methane1010004.

Zimmerle, D.; Vaughn, T.; Bell, C.; Bennett, K.; Deshmukh, P.; Thoma, E. Detection Limits of Optical Gas Imaging for Natural Gas Leak Detection in Realistic Controlled Conditions. Environ. Sci. Technol. 2020, 54 (18), 11506–11514. https://doi.org/10.1021/acs.est.0c01285.

Equipment at the METEC Site