Air Quality STEPPs up Efforts to Locate Leaks

by Whitney Oswald

Storage tanks with combustors

Storage tanks with combustors

Imagine trying to find “invisible” leaks in an oil and gas storage tank. Then try finding these leaks in hundreds of storage tanks scattered across a large, remote area. You know the culprit, and you know these leaks are a significant source of volatile organic compound (VOC) emissions from oil and gas operations in the area. Research shows that these VOCs react with other chemicals in the atmosphere to form ozone, a pollutant occurring at high levels in the region during winter inversions. Finding the leaks is a monumental, but important, task in the effort to reduce the VOCs that contribute to the area’s winter ozone problem. What do you do?

If you’re the Utah Department of Environmental Quality’s Division of Air Quality (DAQ), Bingham Research Center, and the Tri-County Health Department, you take on this challenge and use a $150,000 appropriation from the Utah Legislature to launch a pilot program: the Storage Tank Emissions Pilot Project (STEPP). Using state-of-the-art technology, DAQ scientists are working with the Bingham Center and Tri-County Health to track down leaks in storage tanks at oil and gas wells in the Uinta Basin so operators can repair them.

Oil and gas condensate storage tanks

Oil and gas condensate storage tanks

Approximately 11,400 of the state’s producing and shut-in oil and gas wells are located in the Basin. The large number of wells and the unique air quality problems linked to VOC emissions in the area make it an ideal location to analyze the contribution of fugitive tank emissions. These emissions are aptly named, because they usually leak through a “thief hatch,” a pressure-control device on oil and gas condensate tanks.

Since it would be impractical to visit every one of the 2,350 wells that fall under state air quality regulations, DAQ has worked with oil and gas producers and stakeholders to identify a representative sample of 474 wells that currently have VOC combustors (and thief hatches) on their tanks.

 

DAQ has assembled a powerful collection of tools and techniques to help detect these leaks:

  • Infrared (IR) cameras: Tuned into the infrared wavelengths absorbed by gases like methane, IR cameras allow the user to “see” plumes of gas that are invisible to the naked eye. These cameras, which provide real-time thermal images of gas emissions, help researchers observe and record leaks.
  • Tablet-based Geographic Information System (GIS) equipment: The Uinta Basin region is very remote, so careful trip planning and prior confirmation that sites are accessible are important for the efficient use of staff time and resources. GIS software lets researchers plan the most efficient route for daily site visits and ensures that the sites are reasonably accessible via the local network of roads. GIS overlays of the local roads with the oil and gas well locations help refine the site-selection process.
  • Google High-Resolution Imagery: This tool allows researchers to zoom into each of the potential well sites to verify that the sites selected are good candidates for leak detection. The high-res imagery shows whether there are tanks located at the site, the number of tanks, and a rough idea of the well status (abandoned, remote, isolated, etc.)
High-resolution image shows tanks at the well site (lower left-hand side)

High-resolution image shows tanks at the well site (lower left-hand side)

These tools let researchers plan their site visits with greater precision. The tablet-based GIS application developed by DAQ helps Bingham Center staff navigate the jurisdictionally complex and remote Uinta Basin using real-time GPS-based navigation. Scientists can plan their trips and explore sites using high-resolution imagery before traveling to the site. The tablet-based app also organizes IR video and field notes, creating a database that can be used to analyze the information collected during the site visits.

One of the most important aspects of the STEPP project is the development of a collaborative working relationship between DAQ and the oil and gas companies in the Basin. The STEPP project isn’t about enforcement, it’s about finding solutions. The inclusion of oil and gas producers in the process offers simple benefits, such as access to gated facilities and informal education opportunities to raise operator awareness about leaks in storage tanks. But most importantly, this collaboration facilitates the kinds of cooperative efforts needed to develop innovative and effective ways to reduce the area’s VOC emissions.

The Bingham Center has completed inspections of approximately half of the well sites. DAQ believes that this organized, methodical approach will provide the Division with more definitive information about VOC emissions from storage tanks, improve DAQ emissions estimates in the Basin, and help operators fix leaky storage tanks by providing precise observations that identify VOC sources.

The STEPP program is just one of many air quality research projects underway at the Division of Air Quality. To learn more our research activities in the Uinta Basin and along the Wasatch Front, check out our air quality research website.

3october2016-whitney-web-resizeI am an environmental scientist with the Technical Analysis section at DAQ. I have a Bachelor’s degree in Chemistry from Utah State University and a Master’s degree in Environmental Science from the University of Utah. When not working, I love traveling and spending time outdoors with my husband and two dogs.

 

 

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