Can I identify a flare with a performance issue: Optical Gas Imaging

Can I identify a flare with a performance issue? > Can I identify a flare with a performance issue: Optical Gas Imaging


Infrared cameras are used to observe gas emitted from a flare stack. Where combustion efficiency is low the gas can be seen as a visible ‘black’ plume dispersing from the stack. The method utilises the same technology as used for leak detection and repair activities (LDAR) but is non quantitative.

How it works 

  • Technician observes flares with a forward looking infrared camera from the ground and qualitatively assesses flare performance.
  • Methane and other hydrocarbons from unlit, venting flares appear as black plumes.
  • Poorly combusting flares have visible hydrocarbon slip.
  • OGI flare surveys can be incorporated into leak detection and repair programs.
  • Technician training and survey protocols are critical because the height and radiative heat of flares increase the difficulty of detecting emissions.


  • Can be conducted concurrently with leak detection and repair (LDAR) surveys


  • Cannot measure methane directly or distinguish between gases

  • Non quantitative

  • Requires close access to the flare

  • Observations are dependent upon the skill of the operator

Case study

Uintah Basin survey

  • OGI detection limits were assessed with controlled release testing at the Methane Emissions Technology Evaluation Center. Detection limits increased with technician experience but decreased with distance.
  • Over 3,000 well pads in the Uintah Basin (U.S.) were surveyed with ground-based and helicopter-based OGI. Emissions were detected at 31% of sites with ground surveys, but only 0.5% with aerial surveys due to the higher detection limit.

OGI - Optical Gas Imaging

OGI detects the distinct thermal signature of methane gas as it is emitted in to the atmosphere. It is widely used for activities such as leak detection and repair, but can also be used to identify a flare that is poorly combusting or extinguished.   The majority of observations are qualitative rather than a quantitative assessment of flow.

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