Methane detector network calibration and deployment for monitoring natural gas leaks from buried pipelines

Recent technology advances in methane detection have improved leak detection and repair. However, efforts are hampered in subsurface pipeline scenarios due to the complex nature and extent of such leaks. Soil layers and other subsurface infrastructure and surface conditions play a vital role in the natural gas migration from its point source. To ensure that a known or potential gas leak situation from an underground pipeline is addressed as safely as possible, there is an urgent need for monitoring and evaluating changes to underground gas leakage over large areas and time spans. This is especially relevant for situations where the leak cannot be resolved immediately or in areas of known leakage that require long-term monitoring and evaluation. In this work, we calibrated and deployed a low-cost detector network on the surface to quantify changes in methane concentrations. We performed a series of laboratory and field tests by deploying a gas sensor network in the vicinity of controlled underground gas leaks over a period of 5 days. Our study demonstrates that the sensors can continuously measure the methane variability for extended periods but require calibration for a wide range of temperature and humidity conditions to properly determine the variability in gas (i.e., methane/light hydrocarbon) concentrations. The network approach allows for improved identification and monitoring of underground conditions.