Extension of Methane Emission Rate Distribution for Permian Basin Oil and Gas Production Infrastructure by Aerial LiDAR

Aerial LiDAR measurements at 7474 oil and gas productionfacilitiesin the Permian Basin yield a measured methane emission rate distributionextending to the detection sensitivity of the method, 2 kg/h at 90%probability of detection (POD). Emissions are found at 38.3% of facilitiesscanned, a significantly higher proportion than reported in lower-sensitivitycampaigns. LiDAR measurements are analyzed in combination with measurementsof the heavy tail portion of the distribution (>600 kg/h) obtainedfrom an airborne solar infrared imaging spectrometry campaign by CarbonMapper (CM). A joint distribution is found by fitting the alignedLiDAR and CM data. By comparing the aerial samples to the joint distribution,the practical detection sensitivity of the CM 2019 campaign is foundto be 280 kg/h [256, 309] (95% confidence) at 50% POD for facility-sizedemission sources. With respect to the joint model distribution andits confidence interval, the LiDAR campaign is found to have measured103.6% [93.5, 114.2%] of the total emission rate predicted by themodel for equipment-sized emission sources (& SIM;2 m diameter)with emission rates above 3 kg/h, whereas the CM 2019 campaign isfound to have measured 39.7% [34.6, 45.1%] of the same quantity forfacility-sized sources (150 m diameter) above 10 kg/h. The analysisis repeated with data from CM 2020-21 campaigns with similarresults. The combined distributions represent a more comprehensiveview of the emission rate distribution in the survey area, revealingthe significance of previously underreported emission sources at ratesbelow the detection sensitivity of some emissions monitoring campaigns. New methane emission measurements inthe Permian Basin extendthe distribution of source emission rates beyond the sensitivity limitsof previous studies by 2 orders of magnitude.