The usage and/or disposal of gases for many industries is simply part of their everyday operations. Yet the too frequent corollary to those operations are gas leaks, with all of the perils they may present to the environment, health and safety – including the threat to human life. Finding and repairing leaks quickly and effectively can help to avoid these threats, while providing major economic value by enabling organisations to avoid regulatory fines and reduce product loss. And one solution now recognised by regulators as highly effective in driving down emissions is optical gas imaging (OGI).
A powerful thermal imaging technology, OGI is particularly beneficial for oil and gas systems, as it allows the visualisation of an otherwise invisible gas that is both hazardous and has high greenhouse gas potential. For years, companies have used the technology for a number of tasks such as examining pipe integrity within process equipment. Recently, though, a highly specialised version of these cameras has made its way into the marketplace for a new application—the monitoring of volatile organic compounds (VOCs), such as methane, being vented into the atmosphere.
The US oil and gas industry emitted 13 million tons of methane from its operations in 2015, about 2% of total production, according to a study published in Science (https://is.gd/gubomu). The study found that most of the emissions came from leaks, equipment malfunctions, and other ‘abnormal’ operating conditions. The Environmental Defense Fund estimates that the value of the methane lost to leakage is around $2 billion.
If there were any doubt as to the need to tackle the methane problem, Shane Rogers, IntelliView Technologies’ vice president of R&D, might well disabuse them of complacency. “The total yearly methane emissions from the US oil and gas industry, for example, in cubic feet is 533.7 billion [https://is.gd/oxicip]. That is equivalent to 11 million tonnes of methane – enough to heat over five million homes for a year.”
Such statistics hold more than a passing interest for IntelliView Technologies. According to Rogers, the integration of IntelliView’s proprietary and patented machine learning image processing technologies with FLIR’s uncooled thermal imaging has been the cost-effective catalyst for the continuous monitoring, real-time detection and notification of methane leaks.
“Intelliview and FLIR have worked together to develop the GF77 DCAM-M [dual camera analytic module – methane] automated OGI for methane detection. Along with the GF77a [FLIR Systems’ uncooled autonomous leak detection camera], it also includes a high-definition camera and on-board data processing, using machine learning to detect leak events. It’s focused on remote locations and so uses very low bandwidth.” In action, an OGI alert immediately generates a 15-second video clip picture and live view of any suspected methane leak. “So, within a minute you’ve been able to zero in on the problem and can see what the analytic was seeing by means of the overlay, and know exactly what is happening at that site.”
Rogers does point out that it is probably not cost effective to cover 100% of a site using OGI. “You’re most likely going to target the more complex site components where there is high risk, such as compressors and separators. Also, your detection capability can be affected by background, distance and some environmental factors, which needs to be taken care of in the site design. Finally, you’re not going to be looking for fugitive emissions [slow leaks] with this system. You’re looking for incidents that require immediate attention.”
Where OGI does seem to excel is in allowing operators to build a knowledge base through familiarity with the site monitoring undertaken to review or ‘tour’ sites, seeking out potential leaks or abnormalities, such as ‘hot spots’ on equipment. “This is where it really pays dividends over time,” says Rogers, “thanks to its real-time, 24x7 day-night operation, where no illumination is required, and you get immediate visual confirmation and a high level of quantification.”
Speaking at a panel discussion during the recent Energy Drones + Robotics Summit in Houston, Texas, USA, Maria Araujo, manager of research development at the Southwest Research Institute, said these environmental concerns may now be shaping the market for methane-emissions sensing. She cites recent commitments from major operators to reduce methane emissions as a sign of a shifting attitude.
Significantly, Chevron has committed to tying executive compensation and rank-and-file bonuses to greenhouse gas emissions targets, with a goal to reduce methane and flaring intensity by 20-30% from 2016 levels by 2023. Royal Dutch Shell has made a similar announcement. “I think there’s a public perception aspect of it that’s becoming more important,” states Araujo. “It’s a mixture of that and the regulatory environment. This is coming together to make methane a very hot topic. In the last six months to a year, I’ve seen an increase in appetite for technologies that sense methane emissions.”
In response, optical gas imaging (OGI) technology is giving organisations the solutions they seek to view leakage from their equipment faster and more accurately, helping them meet regulatory emission-reduction requirements and minimise product loss. But how does an OGI camera achieve this? Most importantly, it takes advantage of the absorbing nature of certain molecules to visualise them in their native environments. The camera focal plane arrays and optical systems are specifically tuned to narrow spectral ranges, and only the gases absorbed in the infrared region, which is delimited by a narrow band pass filter, can be detected. Midwave cameras that detect gases such as methane commonly operate in the 3–5 μm range and use an indium antimonide detector.
One company that has been at the forefront of using forward-looking infrared cameras on its facilities is Anadarko. The company first purchased FLIR cameras in 2007, and implemented a voluntary programme to inspect and repair leaks at all production facilities in its Colorado operations. It began conducting weekly audio, visual and olfactory inspections (subject to state regulation No. 7 for VOC tank control requirements).
SEIZING THE INITIATIVE
By 2015, all of its Colorado facilities utilised a combination of AVO inspections and FLIR camera surveys to meet and exceed state requirements. By 2018, it had established FLIR camera inspections at all of its onshore facilities in the USA.
During the Energy Drones + Robotics Summit, Brett Kanda, UAS business development manager for FLIR Systems, commented on how thermal imaging such as OGI allows users to see in total darkness, so an operator inspecting a leak would not need visible light to notice anything. He also underlined how the technology allows users to compare RGB imagery and infrared imagery side by side. While this particular approach has been used more for offshore facilities and in the downstream sector versus linear pipeline inspection, it provides a buffer against false positives, making it easier for operators to verify potential leaks.
“It’s an interesting time in the drone industry, with oil and gas and regulations,” says Kanda. “I think we’re transitioning more into the question of how do we implement this in a large organisation. How do we actually scale? Regulations are going to be a big part of that. I think we’re moving in the right direction.”