Is there a practical and affordable solution for the identification, quantification and remediation of methane leaks in production equipment and facilities? By using the increasingly large amount of data that is being collected from oilfield operations, the combination of satellite monitoring, drone surveillance and on-location sensors could be a data-driven approach to addressing this challenge.
Stakeholders from financial institutions, environmental groups and the public are demanding that the oil and gas industry reduce methane emissions, and many companies have pledged to do so. That should start with establishing a baseline—an accurate understanding of how much methane being emitted and from where—by directing, locating and measuring the large sources that typically account for a majority of emissions. Understanding that big picture will allow prioritization of efforts and establish realistic targets for improvement. Then the ongoing measurement will track progress versus the baseline and demonstrate to stakeholders that delivery on those promises.
Spatial Analysis
Over 80% of information has a spatial component to it, rarely is this being leveraged to add value to operations and the bottom line for the energy industry. With the rapid decrease in cost and increase in access to space, a proliferation of satellite assets can provide unprecedented data for situational awareness and exploration planning. Moreover, the rapid increase in Internet of Things (IoT) sensors and systems allows for near instantaneous monitoring of critical equipment and assets enabling remote operations.
The industry is at a juncture of significant opportunity for oil and gas operations to reach a level of efficiency that was impossible only a few years ago. New data access and management can allow for more efficient identification of high potential prospects by performing desktop recon. Real-time interoperable data streams will increase operational efficiency by leveraging multiple isolated datasets on one common platform.
Spatial analysis or spatial statistics includes any of the formal techniques which studies entities using their topological, geometric, or geographic properties. Complex issues arise in spatial analysis, many of which are neither clearly defined nor completely resolved, but form the basis for current research. The most fundamental of these is the problem of defining the spatial location of the entities being studied. Classification of the techniques of spatial analysis is difficult because of the large number of different fields of research involved, the different fundamental approaches which can be chosen, and the many forms the data can take.
High Level Satellite Monitoring
Satellite remote sensing is one unbiased approach to answer some of the more regional questions. It can help detect active flares especially during nighttime and then be used to calibrate the estimation for flared gas volumes.
In the 1990s, the World Bank started gathering nighttime satellite images, from which big cities and oil fields were both bright and needed to be sorted using additional information. The situation changed in 2012 when infrared data became available from VIIRS. One of the data products, VIIRS Nightfire (VNF) is specialized in natural gas flaring observation and is even able to distinguish between biomass burning and gas flaring.
The resolution of different satellite monitoring tools is important to keep in mind. The Landsat 8 satellite has a spatial resolution of 15-100 meters with a temporal sample rate of 16.0 days. The VIIRS satellite source has a spatial resolution of 375-750 meters with a temporal sample rate of 0.5 days. Both can reveal rich features in the landscape. The Landsat 8 image should be able to identify smaller flares compared to VIIRS images, although the longer satellite revisit time poses a challenge to identify less persistent flares.
Methane may not be as abundant in the atmosphere as carbon dioxide, but with a global warming potential many times greater than carbon dioxide, monitoring and controlling industrial emissions of this potent gas is imperative to helping combat climate change. GHGSat is a New Space initiative that draws on Copernicus Sentinel-5P data for mapping methane hotspots—and its Claire satellite has now collected more than 60 000 methane measurements of industrial facilities around the world.
Copernicus Sentinel-5P’s role is to map a range of atmospheric gases around the globe every 24 hours. Its Tropomi spectrometer delivers data with a resolution as high as 7 km × 5.5 km for methane, but these data can’t be used to pinpoint specific facilities responsible for emissions. However, GHGSat’s demonstration satellite ‘Claire’ can, but it is helped with a bit of guidance from Sentinel-5P.
Drawing on Sentinel-5P data, the GHGSat tasks Claire to home in on methane point sources. Using this approach, GHGSat has been able to attribute large methane leaks to specific industrial facilities. This is catching the attention of managers responsible for emissions from industries such as oil and gas, waste management, mining, agriculture and power generation.
More than a year after announcing an ambitious mission to send a satellite into space to detect methane emissions, the Environmental Defense Fund is marking milestones as it moves closer to launch. The satellite is part of an $88 million donor-funded effort led by the Environmental Defense Fund (EDF). MethaneSAT, an affiliate of EDF, said the satellite will pinpoint methane-emitting sites and the magnitude of such emissions.
Hopes are to launch the satellite by first-half 2022 to support EDF’s efforts to cut 45% of methane pollution from oil and gas sites by 2025. EDF, which has partnered with oil and gas companies on environmental pursuits, plans to continue doing so with methane emissions data and knowledge of technological solutions in hand.
Establishing a More Accurate Baseline
This strategy starts by measuring actual emissions. It would be very time-consuming to measure every source of methane on every well pad across a whole operation, but operators can quickly and inexpensively measure the larger sources that represent the majority of emissions. This is where aircraft and drone monitoring come in play.
Using Drones to Detect Methane Gas in the Oil & Gas Industry
Drones provide many possibilities in a wide range of commercial and industrial applications. From aerial photography and video shooting, to surveys and inspection of structures, the list is endless. Custom drone designs with special sensors are becoming common in the oil and gas industry, where they are helping them to safely and cheaply monitor their assets remotely.
Other than the usual photography, the drone technologies can gather additional information such as gas leaks and thermal images. Pairing the UAVs with the appropriate sensors enables the teams to gather comprehensive data from the remote locations at the fraction of the traditional methods.
One potential and interesting application is the detection of methane gas leaks which are common and a challenge in the oil and gas industry. Usually, the methane gas leaks present risks to the community, users, workers and the environment. The oil and gas companies have the responsibility of preventing and addressing any leaks in the upstream, midstream or downstream components of production and distribution systems.
While traditional methods have been used for a long time, they are slow, risky and costly. Further, inspection workers accessing contaminated areas face a wide range of risks when exposed for long periods. To overcome some of these and other challenges, companies can deploy drones, which provide faster, cost-effective and safe unmanned aerial methane detection solution. A typical application involves attaching a gas sensor to the drone integrated with image, video and location and other sensors or technologies that support the identification of leaking sections of the infrastructure.
The methane detection aircraft and drones detect the leaks by the use of light reflection and absorption sensors. The sensors emit eye-safe lasers which are reflected back in specific ways upon hitting certain matter such as gases. Analyzing the reflected beam enables the drones to pinpoint leaks, including the very small ones. Generally, the sensors can identify the methane spectral signature based on the reflected light; hence determine the presence or absence of the gas.
In a typical inspection, an aircraft or a drone equipped with laser beam sensors flies over the suspected area at a set height. The sensor then beams a laser light on the area while capturing the reflection. If there is the presence of methane gas, it absorbs part of the light and this can be seen in the reflection.
These aerial platforms paired with high-definition cameras work together with the methane sensors to provide real-time images and videos. Some advanced drones with reporting will also show the methane gas concentration and GPS coordinates of the leakage. This enables the teams to identify areas with methane presence and even estimate the levels and rate of emission. Adding other technologies such as infrared thermal imaging enhances the gas detection capability, hence the ability to identify and reduce the leakages.
Ground Level Surveillance
The continuous emissions monitoring technology uses advanced sensors located at the fence line of well sites and production facilities to continuously monitor and report emissions data in near real-time. Timely alerts of emissions events help operators locate and remediate fugitive emissions quickly. Importantly, this data is independently curated and maintained, providing a reliable, verifiable and transparent record of environmental performance.
The final step is performed by the operator’s maintenance crew with routine visual inspections, schedule equipment maintenance and when an emission event is identified a crew will go out to the field with special equipment such as gas sniffers and thermal imaging cameras to pinpoint the exact cause of the leak. Gas leak detection cameras enable the quick and safe detection and visualization of fugitive emissions leaks, allowing the operator to quickly detect and repair leaks, prevent major damage, and avoid fines. These cameras have been used globally for the past decade, and are now recognized by regulators as the best system for emissions reduction.
Bringing all these perspectives together for an integrated view of the air quality and methane emissions from a production site is the concept of a Digital Canopy. While each technique has advantages and disadvantages, different spatial resolution, sampling rates and costs to acquire data, each also has advantages for the operator, industry and regulator in getting a handle of the big picture, identifying major events and responding to the leak with appropriate maintenance steps.