基于观测数据估算渤海油气平台火炬燃烧效率及甲烷排放量

Estimation of Combustion Efficiency and Methane Emissions from Oil and Gas Platform Flarings Based on in Situ Observed Data from the Bohai Sea

基于2012年和2014年船基走航连续观测数据再分析,并结合“自下而上”和“自上而下”法,开展了渤海蓬莱油气田油气平台伴生气火炬燃烧效率和CH_(4)排放量估算研究。结果显示,观测海域油气平台伴生气燃烧导致下风向大气CO_(2)和CH_(4)混合比分别抬升11×10^(-6)~20×10^(-6)和100×10^(-9)~260×10^(-9),估算燃烧效率为(97.8±1.1)%,达到国际先进水平。“自下而上”和“自上而下”法估算全渤海火炬燃烧过程的CH_(4)排放分别达3.6~6.1 Gg/a和1.80~2.68 Gg/a,是人为的CH_(4)强点源。排放因子和观测数据时空代表性等是导致2种方法估算结果不同的主要原因。研究可为海洋油气开采中伴生气回收利用和CH_(4)减排等提供一定的科技支撑。

Based on the reanalysis of ship-borne continuous data observed in 2012 and 2014 and“bottomup”and“top-down”approaches,the combustion efficiency and CH_(4) emission rate of flaring equipped on oil and gas platforms in the Penglai Region of the Bohai Sea were studied.The results showed that peak atmospheric CO_(2) and CH_(4) mixing ratios of approximately(11~20)×10^(-6) and(100~260)×10^(-9) were observed in the downwind area of flaring.The calculated combustion efficiency of associated gas flaring was(97.8±1.1)%,which was better than that in most countries worldwide.The CH_(4) emission rates of flaring equipped on the oil and gas platforms were 3.6~6.1 Gg/a and 1.80~2.68 Gg/a,estimated using the“bottom-up”and“top-down”approaches,respectively,indicating that the flaring was the primary source of atmospheric CH_(4).On the other hand,the difference in the results estimated by the“bottom-up”and“top-down”approaches was still remarkable,mostly due to the limited spatiotemporal representation of emission factors and observation data.This study is beneficial for promoting the recycling and reuse of associated gas and reducing CH_(4) emissions from marine oil and gas exploitation in China.