Methane Quantification Performance of the Quantitative Optical Gas Imaging (QOGI) System Using Single-Blind...

Area of Science:

• Environmental Science
• Chemical Engineering
• Instrumentation & Measurement

Background:

• Optical gas imaging (OGI) is crucial for detecting methane (CH4) leaks in the oil and gas industry.
• Quantitative OGI (QOGI) systems offer potential for rapid, accurate leak quantification.
• Standardized evaluation of QOGI performance is necessary for widespread adoption.

Purpose of the Study:

• To assess the quantification accuracy of the FLIR QL320 QOGI system.
• To evaluate system performance under realistic, near-field conditions mimicking oil and gas operations.
• To identify factors influencing QOGI measurement accuracy.

Main Methods:

• Single-blind experiments were conducted at an outdoor, controlled testing facility.
• 357 measurements were taken for controlled releases of compressed natural gas (0.1–2.9 kg CH4/h).
• Data were analyzed across 26 release scenarios and 71 camera positions.

Main Results:

• 75% of individual measurements fell within a quantification factor of 3 (error: -67% to 200%).
• Individual measurement errors ranged from -90% to 831%.
• Averaging estimates from multiple camera positions reduced errors to -79% to +297%.

Conclusions:

• QOGI system performance is dependent on environmental and operational factors.
• Accuracy improved with higher release rates, clear skies, and low wind speeds (≤1 mph).
• The FLIR QL320 shows promise but requires careful consideration of conditions for reliable methane leak quantification.