Use of Short Duration Measurements to Estimate Methane Emissions at Oil and Gas Production Sites

Methane emission estimates for oil and gas production sites, based on observations lasting seconds to minutes, are becoming more common, but interpreting the emission estimates is challenging. Short-term observations made at the same sites, within days of one another, can lead to very different emission estimates. Using two independent sets of short duration measurements made at a group of 33 dry-gas production sites, this work demonstrates that sets of short duration measurements can be reconciled if distributions of emissions at multiple sites, rather than measurements at individual sites, are compared. This work also demonstrates that short duration measurements made at the equipment level can be extrapolated to longer term emission estimates for individual sites using models that account for intermittency in emissions. This approach can predict expected ranges of emissions for additional sites and can be used to identify site level observations that are outside of predicted ranges, which indicate potential abnormal emissions.