Methane emission detection, localization, and quantification using continuous point-sensors on oil and gas facilities

We propose a generic, modular framework for emission event detection, localization, and quantification on oil and gas facilities that uses concentration data collected by point-in-space continuous emissions monitoring systems (CEMS). The framework uses a gradient-based spike detection algorithm to estimate emission start and end times (event detection) and pattern matches simulated and observed concentrations to estimate emission source location (localization) and rate (quantification). We test the framework on a month of single-source controlled releases ranging from 0.50 to 8.25 hours in duration and 0.18 to 6.39 kg/hr in size conducted at the Methane Emissions Technology Evaluation Center in Fort Collins, Colorado. All controlled releases are identified and 82% are localized correctly. For emissions < 1 kg/hr, the framework underestimates by 37.2% on average, with 90% of rate estimates within a factor of [-4.6, 2.8] or a percent difference of [-78.1%, 178.6%]; for emissions > 1 kg/hr, the framework overestimates by 1.5% on average, with 90% of rate estimates within a factor of [-2.0, 1.8] or a percent difference of [-49.6%, 77.4%] from the true rates. Potential uses for the proposed framework include near real-time alerting for rapid emissions mitigation and emission quantification for data-driven inventory estimation on production-like facilities.