Luis Guanter, Javier Roger, Shubham Sharma, Adriana Valverde, Itziar Irakulis-Loitxate , Javier Gorroño , Xin Zhang, Berend J. Schuit, Joannes D. Maasakkers, Ilse Aben , Alexis Groshenry, Antoine Benoit, Quentin Peyle, Daniel Zavala-Araiza 

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 super-emission events. We use a range of methane-sensitive satellites to document a methane leak from a well blowout in Kazakhstan's Karaturun East oil field in 2023. A dense time series of observations from multiple satellites shows that the leak was active during 205 days. Using 48 high-quality plume observations from this time series, we estimate that a total of 128±36 kt of methane were released to the atmosphere during this leak. Our results reveal that the total methane emissions from the Karaturun 2023 event exceeded those from all previously documented accidents, and highlight the pivotal role of satellites in detecting and quantifying large methane plumes around the planet.