Overview

Quantitative Optical Gas Imaging (QOGI) technology has been used since 2015 in a limited space but has become more common in some industries in the past few years. There have been multiple studies on this technology over the past 10 years with varying results driven by differences in test design, environmental conditions, and intended application context. 

Results from a recent testing at the Total Energies Anomalies Detection Initiatives (TADI) facility in Lacq, France with focus on both fugitive releases (under 1 kg/hr) and high-volume vent releases (5 kg/hr up to 50 kg/hr) add to the other studies on this topic. 

In this testing, the Flir G-Series camera technology with quantification built-in to the camera was evaluated for the release rates that are within the calibrated curves of the current technology (12 g/h to 12 kg/hr), which will be expanded as a result of this testing. The testing of Flir’s Gx320 QOGI in-camera technology included 198 test results from 15 leak test locations and showed similar results as previous studies.

Methane Emission Quantification

Methane (CH₄) is a highly potent greenhouse gas, with a global warming potential more than 80 times greater than carbon dioxide (CO₂) over a 20-year period. Despite its relatively short atmospheric lifespan, methane significantly accelerates climate change due to its intense heat-trapping ability. Major sources of methane emissions include agriculture (particularly livestock and rice cultivation), fossil fuel production, distribution, landfills, and natural wetlands. 

The urgency to measure methane emissions stems from the need to identify and quantify these sources accurately, enabling targeted mitigation strategies. Reliable measurement is essential for tracking progress toward climate goals, informing policy decisions, and ensuring transparency and accountability in emission reduction efforts. Without robust monitoring (and efficient measurement), efforts to curb methane emissions risk being ineffective or misdirected.

Quantitative Optical Gas Imaging (QOGI) has emerged as a transformative technology for methane emissions measurement, building on decades of development in infrared imaging technology for the oil and gas industry. The roots of Optical Gas Imaging (OGI) trace back to the 1980s. OGI technology was first introduced as a commercial product in 2005 by Flir with the GasFindIR. 

This technology provided a unique ability to visualize gas emissions and perform Leak Detection and Repair (LDAR) inspections from safe distances and much more efficiently. However, these systems were qualitative, capable of visualizing gas plumes but not measuring emission rates. The shift toward quantification began in the mid-2010s, notably with the development of the Providence Photonics QL100 and QL320 tablets, which could pair with Flir infrared cameras to estimate methane leak rates using pixel-level analysis of infrared radiation.

The first field deployments of QOGI for methane quantification occurred around 2015, with validation studies conducted by organizations like Concawe and the Alberta Methane Field Challenge (AMFC) and more recent studies like the METEC assessment. These studies tested the accuracy of QOGI systems under controlled conditions, showing quantification errors ranging from +6% to -18%, for the Concawe and AMFC studies, respectively. 

By 2019, after a formal partnership between Providence Photonics and Flir, the oil and gas industry began using QOGI in large-scale field sampling campaigns across oil and gas basins in Colorado, New Mexico, and Texas, demonstrating its practical application for equipment-level methane emission measurements.

Today, QOGI is recognized as a valuable tool for leak detection and repair (LDAR) programs, offering rapid, non-contact quantification of methane emissions from safe distances outside of the plume itself. It is increasingly integrated into regulatory frameworks and industry practices, especially as methane mitigation becomes a priority under policies like the Oil and Gas Methane Partnership (OGMP) 2.0 and methane rules in both the U.S. and EU. 

Despite its promise, ease of use and flexibility for difficult to measure (DTM) sources, QOGI still faces some headwinds in applicability under certain environmental conditions, prompting ongoing research to refine its algorithms and expand its capabilities.

Technology Methodology

Historically and since the introduction of QOGI as a technology in 2015, the ability to measure gas leaks with OGI technology required two devices, an Optical Gas Imaging camera from Flir and a high-performance tablet with proprietary analytics for quantification of gas emissions, the QL320. This was performed in one of two ways, directly connecting the camera and tablet via a USB cable or via post-processing a saved file on the Flir camera. Flir’s G-Series cameras for hydrocarbon, VOC and methane gas imaging were released in April 2023 and included many new features for the OGI industry, including quantification built-into the camera.

Using a QOGI‑enabled camera with integrated analytics, an operator can perform standard LDAR inspections in the field and get direct quantitative results of an emission without the need for any secondary device. This provided a much more efficient and effective way to measure emissions in the oil and gas supply chain. 

Setup for Field Testing

The TADI testing facility located in Lacq, France is world-renowned for testing and qualifying innovative gas leak detection and quantification technologies, primarily CO2 and methane emissions. This facility has broad capabilities to facilitate both small fugitive emissions, in this single digit grams per hour range, to very high-volume vent releases, up to 50 kilograms per hour, at the same testing site.

This testing was performed over four days, and the types of emissions were separated into two categories: fugitive emissions and vent releases.

• For the fugitive emissions, the emission rates ranged from 5 grams/hour (one of the test experiments was for a false negative experiment of 0 grams/hour) up to 612 grams/hour. 
• With the vent releases, the emission rates ranged from 5 kg/hr up to 50 kg/hr.

During this field testing, Flir technicians performed over 1100 measurements from more than 30 test samples to better understand the capabilities of QOGI as a technology and to improve Flir's industry leading quantitative solutions.

Figure 1: Weather conditions in Lacq during testing

During the testing, the camera operator measured from a variety of distances representative of field practice, ranging from 2.5 m to 16 m for fugitive leaks and 4 m to 16 m for vent releases. Conditions also reflected typical day-to-day variability, with morning cloud cover and clearer afternoons, and temperatures ranging from approximately 10-24°C (50-75°F). Wind conditions were generally light to moderate, remaining below 16 km/h (10 mph).

For the testing, the operator of the Gx320 OGI camera had limited field experience in the use of a camera but was supervised by a certified and 20-year experienced OGI camera user who was participating in another technology evaluation simultaneously.

Learnings and Key Insights

With the expansive testing performed, there were several opportunities to learn more about the application, fine tune the technology, and even create new features to meet the needs of the market.

Aggregate Measurements Are More Consistent Than Individual Readings

The testing supported both the underlying theory and prior research, showing improved quantification accuracy in aggregated results, alongside the expected increase in variability across individual QOGI measurements.

Small Fugitive Leaks Show Higher Percentage Error, Lower Absolute Impact

As we separate fugitive emissions from larger vent releases, smaller leaks will have a more dramatic error by percentage when a measured reading deviates from the actual emission, even if only a slight difference, but as you aggregate these fugitive emissions the overall results will be more accurate.

Larger Vent Releases Produce Lower Percentage Error but Greater Emissions Impact

There are multiple applications where aggregate results could be applied in the markets where QOGI is used. Operators could consider using this on a spatial situation by averaging readings over multiple sites or in a broad region where they service or in more of a temporal basis by taking readings over a week, month or even year, like often required for annual emissions inventories. While the individual results may have an error, high or low, the result of using technology like QOGI to measure single source emissions, when aggregated, is likely more accurate than using pre-determined emission factors. 

Measurement‑Based Approaches Prepare Operators for Evolving Regulations

By adopting measurement‑based approaches earlier, operators position themselves ahead of evolving regulatory and reporting frameworks that are increasingly emphasizing quantification, transparency, and source‑level understanding. As regulations continue to develop, these operators are better prepared to meet future requirements without fundamentally changing their workflows. Measurement‑based approaches allow those investments to be reflected over time, demonstrating real progress as reporting expectations shift toward quantification.

Operator Training and Experience Influence Measurement Quality

As we look at the use case of QOGI technology, it is also important to know the user training can also affect the results when using the technology. As part of using QOGI effectively, it is important to recognize that operator training and field experience can influence results. During this trial, the primary operator using the Flir Gx320 in-camera QOGI feature had limited field experience compared with more seasoned users. While QOGI is not overly complicated to use or understand, a short period of training and hands-on practice helps users interpret plume behavior, recognize environmental effects, and apply best practices.

Scene Awareness Is Critical for Quantification 

QOGI image showing the challenges of foreign objects, like LDAR tags, hanging in the scene being measured with an OGI imager.

Understanding the applicable factors involved in QOGI as a technology is also critical to obtaining positive results. These are not challenging or overwhelming but do require minimal understanding of the technology as a whole. One example is related to what is in the scene where a leak is being measured. Quite often, a leak may have been previously identified and needs to be measured with advanced technology, like QOGI. In such a case, there may be a tag or ribbon identifying the leak that needs repair after measurement. In the image above, there is an LDAR tag that is blowing across the scene and moving in and out of the area of measurement for QOGI technology. Basic understanding of the technology would ensure an operator remove this tag before measurement.

Environmental Conditions Can Bias Results but Are Detectable

QOGI image showing pooling effects when a leak stays in one place and does not travel from inside the measurement boundary to cross the ring.

Another example of understanding the technology is knowing how external environmental factors may affect the results. When measuring in windy conditions, it is always best to attempt measurement when the leak is traveling horizontally across the scene since we are using a 2-dimensional technology to measure a 3-dimensional event. And when windy conditions are minimal, a QOGI user would want to ensure that the emission does not “pool” inside the center of the image or move around inside the circle while changing directions multiple times before leaving the measurement ring, which would negatively affect the reading. Above is an example of pooling in an image showing a leak that is moving inside the measurement boundary before leaving the ring. In this case, the measurement would be much lower than expected, but a trained user would see this when operating the camera in the field. To evaluate all conditions a user may experience, we included these results in the testing knowing that an experienced user would exclude them and rerun the QOGI in-caemra measurement.

QOGI Continues to Evolve to Address Real‑World Conditions

While proper training and understanding of the technology will help operators in many scenarios, there are some challenges when using QOGI in the field that are more challenging to overcome. Even with solid training and a sound understanding of QOGI, some field conditions remain inherently difficult to help operators navigate these realities, technology providers—Flir included—have added features designed to reduce the impact of challenging environments and improve measurement confidence. 

Environmental Conditions Can Be Mitigated but Not Eliminated

One specific example is cloudy conditions. Because clouds are composed of fine water droplets, they can appear in the infrared scene and, in some cases, their motion can resemble plume movement—making quantification more complex and, in this study, tending to bias measurements low. Since operators cannot limit measurements to perfect, clear-sky conditions, it is important to understand these effects and apply the available tools to mitigate them. In the image above, the plume moves from left-to-right while there are clouds in the background; the operator therefore masked part of the measurement ring (approximately “6-o’clock” to “11 o’clock”) to reduce background influence. 

Challenging Test Environments Do Not Always Reflect Field Conditions

While TADI and METEC are excellent testing locations for evaluating technologies, one challenge seen in these testing environments is vegetation which is not as common in real-world oil and gas applications.

In the image below, the technology could confuse small movements of grass on the measurement ring, as seen in the bottom half of the ring, as moving gas across the circle. This almost always results in a very high measurement when looking at small fugitive emissions, like this one. A trained operator would know to:

a) choose a different angle of measurement, if possible, or
b) mask out the bottom half of the ring.

Unfortunately, if this leak were moving from the equipment in the center to the bottom of this ring, measurement of this would be challenging and likely cause negative results; in practice, operators should consider repeat measurements, longer measurement duration where appropriate, in addition to the use of masking/scene positioning to improve confidence in the result.

Field Testing Informed Meaningful Product Improvements

During the testing at TADI, the Flir camera operators also noticed some things that can be implemented and improved in the technology. As previously discussed, masking is critical to successful measurement but was previously only available in the legacy Flir QL320 quantification tablet. This feature has been added to the camera and improved by also allowing movement of the ring to any location on the image. 

We also observed situations in which the in-camera QOGI display showed oversaturated leak colorization in areas where no leak was present. In the example above, the reading is very high because the imager is colorizing the equipment, despite no visual emissions in the ring. This can be mitigated through masking but would be extremely apparent to a trained operator. Following learning from this field trial, Flir‘s QOGI technology has been improved to reduce colorization of non-leaking equipment. 

During the TADI testing, there were also some scenarios where a leak was measured, and even seen in the camera, but not colorized in the QOGI imager. With the image above, there was a small, 100 g/hr leak coming from the flange on top of this tank which was measured by the camera but not colorized. This phenomenon has been improved greatly in the newest technology revision.

After testing at the TADI facility, there were several improvements made in Flir’s in-camera QOGI technology. As previously discussed, masking was added to the solution with the ability to move the measurement ring away from the center of the image. The analytics were improved to help ensure measurement accuracy while the plume colorization capabilities were enhanced to ensure colorization of visible emissions and better define the emission movement and dynamics. In the image above, both the masking and new plume color are displayed on a small, butane lighter leak.

Conclusions and Next Steps

Flir’s in-camera QOGI technology proved to be successful at providing aggregate emission estimates during the TADI testing. The results proved that aggregate emission estimates, either temporal or spatial, provide good overall emission inventory results but, on a singular basis, the measurement of emissions that are both turbulent and dynamic in nature can be inconsistent in their results, which can be more challenging with QOGI. To better portray the individual measurement results, the technology from Flir’s G-Series in-camera QOGI solutions has added an uncertainty measurement feature for each reading. This is to help understand source level emission values and align with requirements in some global measurement standards, like OGMP 2.0.In addition, QOGI as a technology allows users not only to measure their emissions, but also to better understand their emissions situation, such as separating measurements of fugitive emissions from operational events.

We also learned that there are some great features in legacy Flir QOGI technology that can be beneficial if added to the camera, like masking. As Flir evolves the technology, there will be more advanced features currently available in the QL320 moved into the camera after some testing, like the super emitter calibration tool and the stabilization feature allowing the use of QOGI without a tripod.

Another learning from the testing is a need to fine-tune our higher volume (vent) calibration curves which has been implemented into the QOGI in-camera technology.

As we look at the landscape of methane measurement over the past 10 years, when Flir and Providence Photonics invented QOGI as a technology, a lot has changed in this time. Ten years ago, the main emphasis in the methane measurement world was around fugitive emissions with little focus on larger, vent type releases. Today, there is a desire to have a broader understanding of all emissions within the methane supply chain from small fugitive leaks to large vent emissions.As Flir has done for 20 years in the OGI world, there will be a continual focus on conditional and iterative innovation improvements of the QOGI in-camera technology to make is easier to use, more accurate, and broadly accepted in methane mitigation applications.

References:

1. TotalEnergies. (n.d.). TADI – Test Center with international reach (Lacq). https://cstjf-pau.totalenergies.fr/en/our-expertise/leveraging-digital-innovation/tadi-test-center-international-reach-lacq
2. Providence Photonics. (n.d.) https://www.providencephotonics.com/
3. Concawe. (2017). Report 17/2. https://www.concawe.eu/wp-content/uploads/2017/01/rpt_17-2.pdf
4. Petroleum Technology Alliance Canada. (2024). Alberta Methane Field Challenge (AMFC) final report. https://ptac.org/wp-content/uploads/2024/01/AMFC-Final-Report.pdf
5. Methane Emissions Technology Evaluation Center (METEC). (2024). METEC assessment. ChemRxiv. https://chemrxiv.org/engage/chemrxiv/article-details/65c40fb19138d23161a5456e
6. FLIR Systems. (n.d.). FLIR Systems completes strategic investment in Providence Photonics LLC. FLIR News Center. https://www.flir.com/news-center/industrial/flir-systems-completes-strategic-investment-in-providence-photonics-llc/
7. Business Wire. (2023, April 4). Teledyne FLIR debuts G-Series Optical Gas Imaging cameras with superior gas quantification and wireless data transfer. https://www.businesswire.com/news/home/20230404005080/en/Teledyne-FLIR-Debuts-G-Series-Optical-Gas-Imaging-Cameras-with-Superior-Gas-Quantification-and-Wireless-Data-Transfer