Isotopic signatures of methane emission from oil and natural gas plants in southwestern China

作者：Dingxi Chen, Yi Liu, Zetong Niu, Ao Wang, Pius Otwil, Yuanyuan Huang, Zhongcong Sun, Xiaobing Pang, Liyang Zhan, Longfei Yu · 发表于：Atmospheric chemistry and physics · 年份：2025 · DOI：10.5194/acp-25-11407-2025 · 被引用次数：2 · 研究领域：Atmospheric and Environmental Gas Dynamics、Hydrocarbon exploration and reservoir analysis、Methane Hydrates and Related Phenomena

Abstract. Current evaluation of methane (CH4) emissions to the atmosphere from global oil and gas (ONG) sector is subject to considerable uncertainty. Particularly for China, few measurements have been conducted, making it difficult to quantify emissions and conduct mitigation measures. Recently, the isotopic composition of CH4 (δ13C) has been used for evaluating the contributions of fossil fuel sources to global budgets, providing a more effective approach across both regional and global scales. Here, we present a field study of CH4 mixing ratios and δ13C based on UAV sampling and ground monitoring across 11 ONG sites located in southwestern China. We found that the values of δ13C-CH4 provide a solid basis for identifying the CH4 leakage and characterizing source distributions at the ONG site-levels, despite that the meteorological and site conditions as well as the surrounding environment could exert influence on the signal strengths. With the Keeling plot approach, we determined that the mean δ13C source isotopic signatures of CH4 emission from these ONG sites were −25.66 ‰, heavier than previously found for other sites globally. This also indicates that they were mainly thermogenic sources. Finally, by incorporating the updated source isotopic signatures determined for China, we conducted a back-of-envelope assessment to qualitatively infer the global CH4 emission from the fossil fuel sources. The result suggests an overestimation of global CH4 emission from the fossil fu...