Methane Super-Emitters in California’s Oil Fields

Methane is a potent yet underestimated contributor to global greenhouse gas emissions. We examined the characteristics of 255 sources of methane super-emitters identified by NASA’s Airborne Visible/InfraRed Imaging Spectrometer-Next Generation in 109 California oil fields. Super-emitter events were primarily associated with oil & gas wells, gas gathering pipelines, and storage tanks (73% of sources). Sources with persistence of <=20% and > 50% comprised 77% and 1% of sources and contributed to 59% and 4% of the total measured emissions, respectively. We estimate total onsite methane emissions from 24 oil fields as 2.3 to 3.4 times the estimated rate by the current official lifecycle assessment model for California’s Low Carbon Fuel Standard used for determining carbon intensity of crude oil production. These findings suggest that without considering direct observations of oil field methane super emitters, greenhouse gas emissions policy for the oil and gas sector is likely to underestimate emissions.