Multi-satellite imaging of a gas well blowout provides new insights for methane monitoring

Abstract:

Methane (CH4) emissions from unexpected oil/gas well control events (e.g., blowouts) have uncertain impacts on global greenhouse gas (GHG) budgets. On November 1, 2019, a gas well blowout was reported in the Eagle Ford Shale near Victoria, Texas USA. Recent advances in satellite remote sensing now allow for independent estimation of CH4 emissions at different spatial scales and revisit frequency. We show that by combining an ensemble of satellite instruments (TROPOMI, GHGSat, PRISMA, VIIRS, SkySat), we quantified time-dependent CH4 emissions multiple times during the 20 day blowout duration. We show the first results from the PRISMA satellite imaging spectrometer, which was tasked to image the blowout after flaring was applied. PRISMA observes top of the atmosphere radiances over a wide range of wavelengths (400-2500 nm) at <12 nm spectral resolution, which we show is sufficient for retrieval of both large CH4 and carbon dioxide (CO2) sources. By comparing retrieved CH4 to CO2, we are able to estimate for the first time flare combustion efficiency from a single instrument. Integrating derived emissions across all satellite instruments, we are able to constrain the total CH₄ lost during the blowout. We validate our findings with ground-based volatile organic compound monitoring that was performed during the blowout, and a bottom-up process based gas well emission model. Our analysis demonstrates the power of combining information from multiple sensors to capture critical emission event dynamics of such incidents. Blowouts are pervasive occurrences across the globe, and multi-satellite observations can enable prompt corrective action as well as quantification of their contribution to national and global methane budgets.