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Abstract

Accidental blowouts in oil and gas wells can result in large and prolonged methane emissions, which are often unreported when happening in remote places. The rapid advancement of space-based methods for detecting and quantifying methane plumes provides an essential tool for uncovering these superemission events. We use a number of methane-sensitive satellite missions, including the Sentinel-5P/TROPOMI global mapper and several high-resolution instruments, to document a methane leak from a well blowout happening in Kazakhstan’s Karaturun East oil field in 2023. A dense time series of plume detections from those satellites shows that the leak was active during 205 days and that most of the emissions were in the range 20–50 t/h. Using 48 high-quality emission rate estimates, we calculate that a total of 131 ± 34 kt of methane was released to the atmosphere during this leak, which exceeds the total emissions from all previously documented accidents. Our study characterizes the evolution and magnitude of the 2023 Karaturun East methane leak and showcases how different types of satellite instruments can be combined to document and quantify methane leaks active during long time periods.