New Oil and Gas Flaring Data Available

Updated data means anyone can see where, and how much, natural gas is being flared in their area.

SkyTruth has updated its Annual Flare Volume map to include 2017 and 2018 data. We first launched the map in 2017 to provide site specific estimates of the annual volume of gas flared during oil and gas production worldwide.

What is flaring?

Flaring is the act of burning off excess natural gas from oil wells when it can’t economically be stored and sent elsewhere. Flaring is also used to burn gases that would otherwise present a safety problem. But flaring from oil wells is a significant source of greenhouse gases. The World Bank estimated that 145 billion cubic meters of natural gas were flared in 2018; the equivalent of the entire gas consumption of Central and South America combined. Gas flaring also can negatively affect wildlife, public health, and even agriculture.

What can I do?

SkyTruth’s map allows users to search the data by virtually any geographic area they’re interested in, then easily compare and download flare volume totals from 2012 through 2018 to observe trends. In addition, it separates flaring into upstream (flaring of natural gas that emerges when crude oil is brought to the Earth’s surface), downstream oil (refineries) and downstream gas (natural gas processing facilities). Residents, researchers, journalists and others concerned about gas emissions in their city or study area can easily determine the sources of the problem using the latest data available, and how much gas has been flared.

VIIRS Satellite Instrument and the Earth Observation Group

The data we use in the SkyTruth map is a product of the Visible Infrared Imaging Radiometer Suite (VIIRS) satellite instrument, which produces the most comprehensive listing of gas flares worldwide. VIIRS data has moved to a new home this year at the Earth Observation Group in the Colorado School of Mines’ Payne Institute for Public Policy. SkyTruth also uses the VIIRS nightfire data in its popular flaring visualization map.

Thanks to the Earth Observation Group for continuing to make the nightfire data freely available to the public! They have authored the following papers for those interested in the VIIRS instrument and how the flare volume is calculated.

Elvidge, C. D., Zhizhin, M., Hsu, F -C., & Baugh, K. (2013).VIIRS nightfire: Satellite pyrometry at night. Remote Sensing 5(9), 4423-4449.

Elvidge, C. D., Zhizhin, M., Baugh, K. E, Hsu, F -C., & Ghosh, T. (2015). Methods for global survey of natural gas flaring from Visible Infrared Imaging Radiometer Suite Data. Energies, 9(1), 1-15.

Elvidge, C. D., Bazilian, M. D., Zhizhin, M., Ghosh, T., Baugh, K., & Hsu, F. C. (2018). The potential role of natural gas flaring in meeting greenhouse gas mitigation targets. Energy Strategy Reviews, 20, 156-162.

What About the Oceans? Mapping Offshore Infrastructure

Mapping stationary structures in the ocean helps us track fishing vessels and monitor pollution more effectively.

We’re all accustomed to seeing maps of the terrestrial spaces we occupy. We expect to see cities, roads and more well labeled, whether in an atlas on our coffee table or Google Maps on our smartphone. SkyTruthers even expect to access information about where coal mines are located or where forests are experiencing regrowth. We can now see incredibly detailed satellite imagery of our planet. Try looking for your house in Google Earth. Can you see your car in the driveway?

In comparison, our oceans are much more mysterious places. Over seventy percent of our planet is ocean, yet vast areas are described with only a handful of labels: the Pacific Ocean, Coral Sea, Strait of Hormuz, or Chukchi Sea for example. And while we do have imagery of our oceans, its resolution decreases drastically the farther out from shore you look. It can be easy to forget that humans have a permanent and substantial footprint across the waters of our planet. At SkyTruth, we’re working to change that.

Former SkyTruth senior intern Brian Wong and I are working to create a dataset of offshore infrastructure to help SkyTruth and others more effectively monitor our oceans. If we know where oil platforms, aquaculture facilities, wind farms and more are located, we can keep an eye on them more easily. As technological improvements fuel the growth of the ocean economy, allowing industry to extract resources far out at sea, this dataset will become increasingly valuable. It can help researchers examine the effects of humanity’s expanding presence in marine spaces, and allow activists, the media, and other watchdogs to hold industry accountable for activities taking place beyond the horizon.

What We’re Doing

Brian is now an employee at the Marine Geospatial Ecology Lab (MGEL) at Duke University. But nearly two years ago, at a Global Fishing Watch research workshop in Oakland, he and I discussed the feasibility of creating an algorithm that could identify vessel locations using Synthetic Aperture Radar (SAR) imagery. It was something I’d been working on on-and-off for a few weeks, and the approach seemed fairly simple.

Image 1. SkyTruth and Global Fishing Watch team members meet for a brainstorming session at the Global Fishing Watch Research Workshop, September 2017. Photo credit: David Kroodsma, Global Fishing Watch.

Readers who have been following SkyTruth’s work are probably used to seeing SAR images from the European Space Agency’s Sentinel-1 satellites in our posts. They are our go-to tools for monitoring marine pollution events, thanks to SAR’s ability to pierce clouds and provide high contrast between slicks and sea water. SAR imagery provides data about the relative roughness of surfaces. With radar imagery, the satellite sends pulses to the earth’s surface. Flat surfaces, like calm water (or oil slicks), reflect less of this data back to the satellite sensor than vessels or structures do, and appear dark. Vessels and infrastructure appear bright in SAR imagery because they experience a double-bounce effect. This means that — because such structures are three-dimensional — they typically reflect back to the satellite more than once as the radar pulse bounces off multiple surfaces. If you’re interested in reading more about how to interpret SAR imagery this tutorial is an excellent starting point.

Image 2. The long, dark line bisecting this image is a likely bilge dump from a vessel captured by Sentinel-1 on July 2, 2019. The bright point at its end is the suspected source. Read more here.

Image 3. The bright area located in the center of this Sentinel-1 image is Neft Daşları, a massive collection of offshore oil platforms and related infrastructure in the Caspian Sea.

Given the high contrast between water and the bright areas that correspond to land, vessels, and structures (see the vessel at the end of the slick in Image 2 and Neft Daşları in Image 3), we thought that if we could mask out the land, picking out the bright spots should be relatively straightforward. But in order to determine which points were vessels, we first needed to identify the location of all the world’s stationary offshore infrastructure, since it is virtually impossible to differentiate structures from vessels when looking at a single SAR image. Our simple task was turning out to be not so simple.

While the United States has publicly available data detailing the locations of offshore oil platforms (see Image 4), this is not the case for other countries around the world. Even when data is available, it is often hosted across multiple webpages, hidden behind paywalls, or provided in formats which are not broadly accessible or useable. To our knowledge, no one has ever published a comprehensive, global dataset of offshore infrastructure that is publicly available (or affordable).

Image 4. Two versions of a single Sentinel-1 image collected over the Gulf of Mexico, in which both oil platforms and vessels are visible. On the left, an unlabelled version which illustrates how similar infrastructure and vessels appear. On the right, oil platforms have been identified using the BOEM Platform dataset.

As we began to explore the potential of SAR imagery for automated vessel and infrastructure detection, we quickly realized that methods existed to create the data we desired. The Constant False Alarm Rate algorithm has been used to detect vessels in SAR imagery since at least 1988, but thanks to Google Earth Engine we are able to scale up the analysis and run it across every Sentinel-1 scene collected to date (something which simply would not have been possible even 10 years ago). To apply the algorithm to our dataset, we, among other things, had to mask out the land, and then set the threshold level of brightness that indicated the presence of a structure or vessel. Both structures and vessels will have high levels of reflectance. So we then had to separate the stationary structures from vessels. We did this by compiling a composite of all images for the year 2017. Infrastructure remains stationary throughout the year, while vessels move. This allowed us to clearly identify the infrastructure.

Image 5. An early version of our workflow for processing radar imagery to identify vessel locations. While the project shifted to focus on infrastructure detection first, many of the processing steps remained.

Where We Are Now

Our next step in creating the infrastructure dataset was testing the approach in areas where infrastructure locations were known. We tested the algorithm’s ability to detect oil platforms in the Gulf of Mexico, where the US Bureau of Ocean Energy Management (BOEM) maintains a dataset. We also tested the algorithm’s ability to identify wind turbines. We used a wind farm boundary dataset provided by the United Kingdom Hydrographic Office to validate our dataset, as well as information about offshore wind farms in Chinese waters verified in media reports, with their latitude and longitude available on Wikipedia.

Image 6. Wind farms in the Irish Sea, west of Liverpool.

Our results in these test areas have been very promising, with an overall accuracy of 96.1%. The methodology and data have been published by the journal Remote Sensing of Environment. Moving beyond these areas, we are continuing to work with our colleagues at MGEL to develop a full global dataset. What started as a project to identify vessels for GFW has turned into an entirely different, yet complementary, project identifying offshore infrastructure around the world.

Image 7. This animated map shows the output of our offshore infrastructure detection algorithm results (red) compared to the publicly available BOEM Platform dataset (yellow).

In addition to helping our partners at Global Fishing Watch identify fishing vessels, mapping the world’s offshore infrastructure will help SkyTruth more effectively target our daily oil pollution monitoring work on areas throughout the ocean that are at high risk for pollution events from oil and gas drilling and shipping (such as bilge dumping). This is also the first step towards one of SkyTruth’s major multi-year goals: automating the detection of marine oil pollution, so we can create and publish a global map of offshore pollution events, updated on a routine basis.

Be sure to keep an eye out for more updates, as we will be publishing the full datasets once we complete the publication cycles.

More oil pollution in southeast Asia: suspected bilge dumping off Indonesia and The Philippines

[This analysis of oil pollution in the waters of southeast Asia was written as part of a collaborative effort between SkyTruth team members Lucy Meyer and Brendan Jarrell.]

Our routine monitoring of the world’s oceans has led to some extraordinary findings. For example, in previous updates, we’ve identified oil slicks in traffic-heavy locations like the Strait of Malacca. But as you’ll see in this post, bilge dumps occur elsewhere in southeast Asia. 

Those who follow our posts are probably familiar with how we identify vessels at sea. To new readers, let us explain what bilge dumping is and how we identify potentially responsible vessels. Bilge dumping is the disposal of waste water from a ship’s lower hull. Bilge water is supposed to be treated before it’s discharged, but sometimes vessel operators will bypass the pollution control equipment and flush oily, untreated bilge into the ocean – in direct violation of marine pollution law. We use images from satellites to monitor for illegal bilge dumping. In satellite imagery, oily bilge dumps usually form distinctive linear slicks. By matching the time of the imagery to broadcasts from a vessel tracking service called automatic identification system (AIS), we can determine the identity of vessels that appear to be causing the slicks. We used this process to identify the vessel associated with a long bilge slick in Figure 1 below.


Figure 1: A vessel shown passing through the Sunda Strait, identified as the Sungai Gerong, apparently trailing a long oily bilge slick.


This Sentinel-1 radar satellite image from July 2nd shows a slick about 177 kilometers long around the southwest tip of Banten Province, Island of Java, Indonesia (Figure 1). In the yellow box, you can see a vessel at the head of the slick. By investigating AIS broadcasts from exactEarth’s ShipView service, we identified an Indonesian oil products tanker named the Sungai Gerong as the likely vessel. The satellite scene, captured at 22:33 UTC (Coordinated Universal Time), shows a slick that closely aligns to the AIS broadcasts from the Sungai Gerong.

You’ll probably notice that the tail-end of the slick is a bit contorted and offset from the track of the Sungai Gerong. The slick’s appearance was likely influenced by ocean currents and local weather conditions between the time of the ship’s passing and when the image was taken. Global wind maps show that there were 10-15 knot winds blowing northwest up to six hours before the image was acquired. This data suggests that wind likely impacted the slick’s appearance. As a result, we believe that the Sungai Gerong is the likely source of this slick.

Using AIS, we tracked the Sungai Gerong as it traveled north through the Sunda Strait — the body of water between the Indonesian islands of Java and Sumatra — to the port of Jakarta. Similar to the Strait of Malacca, the Sunda is an important waterway that connects the Indian Ocean to the Java Sea. Though not as dense with marine traffic as the Malacca Strait, the Sunda is still subjected to pollution from vessels. 

We also recently identified two suspected bilge dumps in the Philippines (Figure 2). Occurring on July 6th in the South China Sea, a 238 kilometer long slick behind the vessel in this Sentinel-1 radar image looks like a bilge dump. The Philippine island of Palawan, a popular tourist destination for its beautiful natural landscape, appears on the right side of the map frame. Another smaller slick without a known source is visible to the left of the larger slick.


Figure 2: The Ulaya makes its way through the South China Sea. Palawan Island, a part of the Philippines, can be seen to the right.


Using AIS broadcasts from ShipView, we identified the Ulaya, a Thai oil tanker, as a possible source of the slick. The last AIS broadcast from the Ulaya (seen directly above the ship) was transmitted fifteen minutes before the image was captured. These AIS broadcasts give us reason to believe that the Ulaya could be responsible for this slick. Moreover, ShipView shows that the vessel was headed towards the Port of Belawan in the Strait of Malacca with a shipment of  Dangerous Goods. According to the International Maritime Organization, a United Nations agency that regulates global shipping, chemicals falling under this classification are “hazardous to marine environments.” Thus, a slick from this ship could be of greater concern than usual.

These examples show that bilge dumping continues to be a problem in the waters of southeast Asia. But with satellite imagery, anyone, anywhere can see what’s happening on the water and help to raise the alarm. We hope that our persistent and careful surveillance will inspire others to pressure policy makers, government regulators, and the shipping industry to take strong, coordinated action to stop bilge dumping.

“Well Kick” Causes Spill in Java Sea

Following up on recent reports of oil in the water off the north coast of Karawang Regency, West Java, Indonesia, SkyTruth has picked up a slick in Sentinel-1 radar imagery. In the image from July 18th, an unidentified platform (circled in red) located roughly 12 km north of the Karawang shore is shown emitting a 34.7 km-long slick into the Java Sea. A story written by the local Jakarta Post on July 18th describes state-owned energy firm Pertamina’s decision to evacuate personnel and halt operations at an offshore production rig in their Offshore Northwest Java (ONWJ) block. The evacuation was ordered after a dangerous “well kick”, or unplanned release of gas caused by low pressure in a wellbore, initiated a large slick on the 16th of July. A separate report released by the Jakarta Post five days later indicated that the Indonesian Transportation Ministry teamed up with Pertamina in response to the oil-related event, along with several other smaller entities in the area. The response vessels were able to set up a boom around the perimeter of the offshore platform. Unfortunately, this didn’t stop oil from reaching villages and beaches on West Java’s coast. Given the fact that several vessels surround the unidentified object in the Sentinel-1 image, we believe that this could be the affected drilling platform. Pertamina’s upstream director Dharmawan Samsu estimated that it will take approximately eight weeks for the oil and gas leakage to be plugged.

The unidentified platform (circled in red) can be seen leaking oil into the Java Sea. Several small vessels are in the platform’s proximity.

Visualizing the Expansion of Fracking in Pennsylvania: Part 3

If you have been following the first two posts in this series, you have been introduced to Pennsylvania’s hottest commodity: natural gas. The state has experienced a drilling boom with the development of the Utica and Marcellus shale formations, which underlie approximately 60% of the state. With Dry Natural Gas reserves estimated around 89.6 trillion cubic feet in 2017 (roughly ⅕ of the US total), natural gas development will likely play a big part in Pennsylvania’s future. The method for extracting natural gas from porous rock underneath the Earth’s surface, usually horizontal drilling paired with hydraulic fracturing (or “fracking”), is an extremely disruptive industrial process that could present significant human health and environmental repercussions (see also this compendium of public health studies related to fracking). Allegheny County, the focal point of SkyTruth’s previous analyses, has survived largely unscathed to this point, but developers have high hopes of expanding into the county.  

In order to see just how quickly natural gas development can expand, Allegheny residents need not look far. Allegheny’s neighbor to the south, Washington County, has become a critical site of natural gas production for the state of Pennsylvania. Not only does Washington County rank second in production among all Pennsylvania counties, but it also recently moved ahead of Susquehanna County as the home of the most active wells in Pennsylvania. Washington County is considered a part of the Pittsburgh metropolitan area, with a population of approximately 207,000. Though this is a fraction of the population of Allegheny County, its close proximity could prove indicative of what is to come in the county if stricter regulations are not put in place. In our final entry of this series, we will examine the expansion of drilling and fracking in Washington County, with eyes toward how the trends here might carry over to Allegheny County.



The area shown above lies close to the town of West Finley, PA and surrounds the perimeter of the Four Seasons Camping Resort (shown in the center of this image series). This area is right on the PA/WV border, within the heart of the Utica and Marcellus formations. These images show the growth of drilling infrastructure in a relatively low population setting.


The image above (courtesy Google) gives us a closer look at one of the drilling fluid impoundments which can be seen at the top left corner of the previous scene. SkyTruth recently wrapped up its 2017 FrackFinder update, which mapped the extent of new drilling in Pennsylvania between 2015 and 2017. According to our findings, the average size of one of these impoundment is 1.4 acres, slightly larger than the average football field. These ponds sometimes hold fresh water, and at other times are temporarily storing leftover fluid used in the hydraulic fracturing process which can contain volatile, toxic chemical additives.



This second area sees significant well pad development from 2008 to 2017. Located right outside the small town of Bentleyville, PA, several wells are constructed along this bend of I-70. This area is made up of former coal towns.  Mining facilities dot the landscape, indicating that residents of this area are no strangers to resource extraction.



This third series of images shows the massive development of the agricultural land surrounding Cross Creek Lake, located right outside of West Middletown. Cross Creek County Park (outlined in black), which encompasses the lake and its surrounding area, is the largest park in the county and serves as a convenient day retreat for residents of the city of Washington, PA, Washington County’s largest city. Many people come to the lake to fish, but the fracking operations in the park could prove to be detrimental to the health of the lake’s fish, according to recent research.



This close-up on an area at the Southwestern portion of the park (courtesy Google Earth) shows a children’s playground that lies just under 1500 feet away from an active drilling site (at lower right). This is well within the proximity suggested to be potentially hazardous to public health.



This final image series is taken from right outside the Washington County towns of McGovern and Houston. The drilling operations, which pop up in just four years, are located in close proximity to developing neighborhoods, parks, The Meadows Racetrack and Casino, and the Allison Park Elementary School. Unlike the other images depicted throughout this evaluation, this development takes place around a well established suburban area, where public safety could be at risk should disaster strike at one of these drilling locations.



The image above (courtesy Google) presents yet another example of just how close these drilling sites are built to residential areas in some instances. Massive industrial development could be seen and heard from one’s back porch!

This is all happening directly south of Allegheny County, so it is plausible that similar development could take place there.

Allegheny County is in an unique situation given its location, its population density, and its relatively low levels of natural gas development. As pressures on Allegheny County mount, we hope that these bird’s eye view evaluations of drilling in nearby counties will help to enlighten and inform policy moving forward. To see SkyTruth’s analysis of the effect that setback distances can potentially have on natural gas development in Allegheny County, please follow the link provided here.

This is the final entry in a three-part series visually chronicling the expansion of fracking across Pennsylvania.  This series is meant to complement our work mapping setback distances and potential adverse public health consequences in Allegheny County, PA.  For more about our setbacks work, please check out our blog post and interactive web app. To read the first entry in this series, please follow this link. To see the second entry in the series, click here.