Enhanced Gas Leak Visualization Tools Accelerate Better Decision Making

Special to Pipeline & Gas Journal
October 2009 Vol. 236 No. 10

For operators of underground transmission pipelines and/or aboveground natural gas processing facilities, finding and fixing “fugitive emission” leaks continues to be a business-critical task for safety, environmental stewardship, preservation of a finite resource and revenue enhancement. And for those engaged in natural gas exploration, finding and capturing methane emissions from naturally occurring underground sources is an additional motivation.

The question is: How can the process of finding leaks, emissions and seeps – and taking action on those findings – be accelerated? Increasingly, industry leaders in each of these segments are turning to companies which specialize in enhanced leak- and seep-detection and visualization tools needed to inform and guide critical business decisions in real time.

Visualizing Natural Gas Transmission Pipeline Leaks
Surveying underground natural gas pipelines for leaks remains critical to ensure public safety, continuity of service and environmental protection, not to mention necessary to comply with regulatory requirements. While gas lines have traditionally been leak-surveyed by walking the lines to measure for elevated concentrations of gases, this consumes a great deal of time and resources as well as putting the line workers’ safety at risk.

To address this ongoing challenge, ITT Corporation developed Airborne Natural Gas Emission Lidar (ANGEL) Services, delivering a safe, cost-effective way to aerially survey extensive networks of underground pipelines for leaks while maintaining a high level of accuracy and sensitivity. In the context of transmission pipeline surveys, customers say ANGEL Services combines the speed, efficiency and practicality of an aerial visual patrol with the confidence of an instrumented leak survey.

With a growing recognition that walking transmission pipelines in search of leaks is time-consuming and prone to missing leaks, the industry’s more progressive transmission pipeline operators have increasingly been turning to the advanced leak detection and visualization services. One such firm is Northern Natural Gas (NNG), headquartered in Omaha, NE.

NNG recognized the daunting task of walking its pipelines to fulfill its periodic pipeline leak-survey requirements to satisfy U.S. Department of Transportation regulations and selected ITT to perform aerial leak surveys over a specific pipeline segment. Jeff Cullison, regional pipeline specialist, said that decision was “based on proven accuracy as well as the short time duration to cover the network.”
On one survey flight over the NNG segment, a new underground leak indication was detected. Based on the data collected, NNG was presented with the exact spatial location and plume visualization of a major underground pipeline leak (Figure 1). Upon investigation, the leak represented a serious safety concern. “This crack probably wouldn’t have been discovered for another year - when the pipeline was next scheduled for inspection,” said Cullison. “Or, it would have split open.” But a pipeline integrity issue was quickly identified and a potential disaster averted.”

Image 1.jpg
Figure 1: An example of an underground pipeline leak found and visualized - a two-dimensional visualization of a three-dimensional gas plume. (Courtesy of Northern Natural Gas)

This customer deliverable imagery visualizes: