Methane emissions from oil and gas platforms in the Bohai Sea, China.
Methane emissions from oil and gas platforms in the Bohai Sea, China.
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DOI：
10.1016/j.envpol.2020.114486
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发表时间：
2020-04
影响因子：
8.9
通讯作者：
Kunpeng Zang;Gen Zhang;Juying Wang
中科院分区：
文献类型：
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作者：
Kunpeng Zang;Gen Zhang;Juying Wang
虽然石油和天然气勘探有助于大气甲烷（CH 4）的排放，其影响和沿着中国大陆架海的影响仍然知之甚少。从2012年到2017年，我们在中国渤海的海水柱和边界层中进行了四次CH 4的船基调查，并进一步测量了CO2和几个气象参数。2012年11月，边界层中CH 4混合比和海水柱中CH 4浓度的平均观测值为1950 ± 46 ppb（本次调查未观测到溶解甲烷），2014年8月为2222 ± 109 ppb和13.0 ± 5.9 nmol/L，2014年2月为2014 ± 20 ppb和5.4 ± 1.4 nmol/L，2017年5月分别为1958 ± 25 ppb和5.3 ± 3.8 nmol/L。结果表明，油气平台排放的CH 4占当地大气CH 4本底增量的72.5 ± 27.0%。其余的排放量归因于海陆气团输送。相反，海气交换的影响可以忽略不计，测量范围为10 - 3 ppb。在碳平衡标定中，基于CO2增量（ΔCO2）和CO2与CH 4增量之和（ΔCO2+ Δ CH 4）的平均燃烧效率为98.5 ± 0.5%。此外，石油和天然气平台的CH 4排放速率为0.026 ± 0.017 Tg/年，约为整个渤海海域大气CH 4排放通量的7.2倍。因此，油气平台是渤海大气CH 4的重要人工热点源。
Although oil and gas explorations contribute to atmospheric methane (CH4) emissions, their impact and influence along the shelf seas of China remain poorly understood. From 2012 to 2017, we conducted four ship-based surveys of CH4in the seawater column and boundary layer of the Bohai Sea, China, and further measured CO2and several meteorological parameters. The average observed CH4mixing ratios in the boundary layer and its concentrations in seawater column were 1950 ± 46 ppb in November 2012 (dissolved CH4was not observed in this survey), 2222 ± 109 ppb and 13.0 ± 5.9 nmol/L in August 2014, 2014 ± 20 ppb and 5.4 ± 1.4 nmol/L in February 2017, and 1958 ± 25 ppb and 5.3 ± 3.8 nmol/L in May 2017, respectively. The results demonstrated that the CH4emissions from the oil and gas platforms accounted for approximately 72.5 ± 27.0% of the increase in the background atmospheric CH4in the local area. The remaining emissions were attributed to land–sea air mass transportation. Conversely, the influence of the air–sea exchange was negligible, measuring within the 10−3ppb range. For carbon balance calibration, the mean flaring efficiency of the oil-associated gas based on the enhancement of CO2(ΔCO2) and enhancement sum of CO2and CH4(ΔCO2+ ΔCH4) was 98.5 ± 0.5%. Furthermore, the CH4emission rate from the oil and gas platforms was 0.026 ± 0.017 Tg/year, which was approximately 7.2 times greater than the sea-to-air CH4flux over the entire Bohai Sea area. Thus, oil and gas platforms must be recognized as important artificial hotspot sources of atmospheric CH4in the Bohai Sea.