Monitoring oil and gas field CH4 leaks by Sentinel-5P and Sentinel-2

Abstract

Methane (CH₄) ranks as the second most abundant greenhouse gas globally, following carbon dioxide (CO₂), constituting approximately one-sixth of total greenhouse gas emissions. While CH₄ levels in the atmosphere are lower compared to CO₂, the warming potential of CH₄ greatly surpasses that of CO₂. With a relatively short atmospheric lifespan of approximately 12 years, mitigating CH₄ emissions presents a viable means to alleviate the impacts of climate change on human populations within a concise timeframe. The atmospheric sources of CH₄ primarily stem from two categories: natural and anthropogenic. A small number of super-emitters frequently contribute significantly to the overall regional emissions. Monitoring and repairing leaks from super emitters of CH₄ is a low-cost and effective way to slow down the greenhouse effect. Remote sensing satellites have gradually become an effective means of monitoring CH₄ leakage due to their low cost and large coverage. There is a range of satellites that can be used to monitor CH₄ concentrations and emissions, such as Sentinel-5P, GOSAT, GHGSat, Sentinel-2, GaoFen-5, Landsat, and so on. Because the pixel resolution is rough (about 7 km), Sentinel-5P (S5P) can only identify high-value CH₄ anomalies in some areas, making it difficult to identify and monitor point source CH₄ emission plumes. Sentinel-2(S2) can accurately detect CH₄ leakage in band-11 and band-12 with high pixel resolution (about 20 m) but with every 5-day revisit time. In this paper, we monitored and quantified oil and gas field CH₄ leakage using a combination of S5P and S2 data by taking advantage of the high temporal resolution (daily) of S5P and high spatial resolution (20 m) of S2. We used S5P data to find CH₄ anomalies. Then we used S2 to zoom in on this location to find CH₄ plumes. We used three different methods: Single-band–multi-pass (SBMP), Multi-band–single-pass (MBSP), and Multi-band-multi-pass (MBMP) to identify CH₄ plumes. Using these methods, we successfully monitored three emission source cases (Algeria, Mexico, and Turkmenistan) and discussed them. Through the above three cases, we can conclude that the MBMP method has higher stability in identifying S2 CH₄ plumes.