Earlier this year, the Environmental Protection Agency (EPA) published Regulation 40 CFR, Part 60, Sub-part OOOOa, commonly known as Quad Oa, and finally brought optical gas imaging (OGI) firmly into the mainstream. This presents a major shift in the way fugitive emissions are regulated, and the technology that can be used.
Detecting and acting on gas leaks is naturally a major concern for oil and gas operators, and a challenging problem to address. OGI technology started to play a role about ten years ago, when companies began to use it to reduce the damage caused by major – and minor – gas leaks to public health, the environment, and corporate profits. At that time, the EPA had a series of robust protocols around gas leak detection, known as Method 21, that relied on the use of ‘sniffers’ – devices that use a physical or chemical reaction to identify the presence of leaked gas.
Sniffers have proved to be a reliable method of detecting the presence of leaking gas in the atmosphere by measuring the gas concentration in parts per million (ppm) in a sample of air. If gas is present where it shouldn’t be, a sniffer will pick it up. However, there are some limitations to sniffer technology. Method 21 is a labor intensive process; operators have to cover thousands of components and measure gas concentrations for each one. However, sniffers can only detect the presence of gas in very close proximity to components being inspected. As a result, leaks from unexpected or hard to reach sources can go undetected.
Sniffers are not designed to detect the specific source of a leak, and therefore may result in delays or failures in repair and further losses. What’s more, sniffers also require routine calibration and are prone to 'poisoning' when exposed to concentrations beyond a certain level. Furthermore, since sniffers measure concentrations and not flow rates, in order to quantify the greenhouse gas (GHG) environmental impact of a leak based on the ppm reading, calculation formulas are required. These formulas use complex empirical and statistical data to translate ppm to tons of CO2 equivalent figures.
This is where OGI comes to the fore. By using an infrared thermal-imaging camera that visualizes hydrocarbons based on their unique electro-magnetic radiation absorption patterns, OGI enables operatives to observe the plume of leaking gas. They can then literally see the gas through the camera, find the source of the leak with pinpoint accuracy, and take swift mitigating action to fix it – even when the ppm rate is relatively low. An OGI camera can also record video thus giving verifiable proof that a particular leak has been fixed.
Since 2008, OGI devices have been used as an alternative to sniffers in remote or hazardous locations, as well as for non-scheduled inspections. Later, the EPA recognized for the first time that OGI technology offered certain advantages, and updated their written regulations to say that it could be used as an alternative work practice (AWP) to Method 21 sniffers.
However, until recently the EPA only permitted the use of OGI for three out of four routine quarterly inspections, with sniffers being mandatory for the fourth. This particular ruling slowed down the adoption of OGI, since it required operators to invest in and deploy an additional technology to what they were already using.
The new legislation, which came into effect in August 2016, and will become mandatory by June 2017, changes all that. The EPA has recognized that OGI is the best system for reducing (BSER) hydrocarbon emissions in the upstream and midstream oil and gas industry. Under the terms of QuadOa, OGI technology may be used as the only leak detection method in well sites and compressor stations for all routine inspections, whether quarterly, semi-annually or annually.
The regulation does allow for the continued use of Method 21 sniffers, but the supporting documents show that OGI inspections are up to four times faster than Method 21, and therefore significantly more cost-effective. With a new regulatory framework in place, the stage is set for widespread adoption of OGI.
But what can companies interested in reducing the costs and increasing the effectiveness of their routine inspection regimes do to prepare for the June 2017 deadline? There are three aspects that operators should consider in OGI technology:
Compliance with OOOOa requirements. The first thing is to look for appropriately certified and compliant tools. In addition to identifying OGI as the best system to use for reducing emissions, the regulations also give specifications on what the technology should be able to do.
Operators must ensure the equipment they choose is capable of detecting hydrocarbons by working selectively in the correct spectral band (OGI cameras that use a cooled MCT detector with a spectral band of 3.2-3.4 um will meet this requirement).
QuadOa requires a very sensitive OGI camera that can detect a small leak with a flow rate of 60 g/h comprising 50 percent methane and 50 percent propane in a concentration of 10,000 ppm. Any technology chosen must have the appropriate certifications, and come from certified manufacturers that can verify compliance with the new regulations.
Operators should also check that the OGI camera can record, store and retrieve video of the inspection process, including date, time and GPS location as evidence for future regulatory audits.
Environmental suitability. If OGI is to be the standard tool for routine inspections, it has to be suitable for the unique challenges posed by the oil and gas operating environment. In particular, it has to be able to withstand the harsh conditions typically found in upstream and midstream operations.
Operators should look for camera equipment that is certified for hazardous locations: with UL Class 1 Div 2 certification. Not only will this ensure the equipment is appropriate for the safety requirements of the environment, it avoids the need to go through the process of securing an individual 'hot permit' for every use.
Daily operation. The new regulations represent a significant step-up in the use of OGI technology, as it becomes a routine method rather than a specialized tool. Therefore, it is important to consider that the equipment will now be used on a much more frequent basis, in all weather conditions and during long hours of operation.
The design and ergonomics of the equipment should be taken into account: Is it made from appropriate materials to withstand the wear and tear of day-in day-out field use? Is it sealed against dust and water to enable use in those conditions? Is it light enough to be portable? Can it easily be operated with gloves? Does it provide sun glare protection and image magnification for eyeglass wearers? Is the camera suitable for long hours of continuous inspection? Since using one eye can induce dizziness, fatigue and strain, is it equipped with a large LCD display that allows operators to observe naturally with both eyes open?
The new regulations come at a time when all operators are driving cost-efficiencies throughout their operations in order to maximize production. Choosing the right technologies enables operators to meet both of these demands while keeping people and the environment safe: minimizing losses from lost product, shortening the time to detect and repair critical assets, reducing the risk of potential fines and damage to reputation and share price. OGI is certainly a technology whose time has come.