Abstract：
Methane is the second largest greenhouse gas after carbon dioxide. The emissions of methane inevitably occur along
the entire oil & natural gas supply chains. Under the vision of being carbon neutral by 2060, China's oil & gas industry has an
urgent need to reduce methane emissions. Accurate accounting and evaluation of fugitive methane emissions is a prerequisite for
the oil and gas industry to carry out methane emissions control. Based on the emission factors recommended by 2019 Refinement
to the 2006 IPCC Guidelines for National Greenhouse Gas Inventory, we estimate the fugitive methane emissions from China’s
oil & natural gas systems from 2000 to 2017, identify the main features of temporal and spatial inventory changes, and compare
the inventory data with those adopted from existing studies. The results show that methane emissions from China’s oil & natural
gas systems increased continuously, from 703.6 Gg (low emission scenarios)~970.4 Gg (high emission scenarios) in 2000 to
1697.3~3288.3 Gg in 2017. The methane emissions of the oil system increased from 561.9~648.0 Gg in 2000 to 696.6~783.0 Gg
in 2017; methane emissions from the natural gas system continued to grow, from 141.7~322.5 Gg in 2000 to 1000.7~2505.3 Gg
in 2017. The natural gas system had a much larger growth rate of fugitive methane emissions than the oil system. Considering
most activities occurring with lower-emitting-technologies and practices, the production segment of the oil & natural gas industry
is the key emission source. The transportation segment of the natural gas system is an important emission source under the
condition of most activities occurring with higher-emitting-technologies and practices, suggesting large mitigation potentials in
different fields. From the point of view of spatial characteristics, the distribution of methane emissions in China’s oil & natural
gas industries of China shows the trend of shifting from Northeast and North China to Northwest and Southwest China, along
with the layout change of oil & natural gas resources exploration and development. Comparing with the results of the existing
inventory research, it is found that there is still a great uncertainty in the estimation of methane emission from oil & natural gas
systems in China, owing to the differences on the completeness of emission sources, accounting methods and data accuracy.
Finally, this study provides some suggestions to develop the inventories of methane emissions in China’s oil & natural gas
industries, such as the normalization of national inventory compilation, the improvement of accounting methodology and the
implementation of high-resolution source monitoring.
