四川盆地气矿天然气开发过程中温室气体的排放特征

Greenhouse Gas Emissions from Natural Gas Development Process in a Gas Field in Sichuan Basin

天然气开发过程是化石能源系统重要的排放源之一.包括我国在内的发展中国家对于油气系统温室气体排放的研究尚处于起步阶段,并且也无统一的计算方法.为研究我国天然气开发过程中温室气体排放情况,以四川盆地某较大规模(年产气量约16×108m3)的天然气气矿为研究对象.利用甲烷泄漏浓度检测仪对该气矿井口、集气站、配气站等场站的所有元件的潜在泄漏点进行了逐一检测,同时采集油田水和天然气样品,在实验室对油田水露天放置过程和天然气火炬燃烧过程的温室气体排放进行了模拟研究,计算了该矿2011年天然气开发过程中温室气体排放量.结果表明:2011年研究气矿CH4和CO2排放量分别为1 033.32和1 295.56 t,折合CO2当量为27 128.56 t.与采用IPCC(政府间气候变化专门委员会)《2006年国家温室气体清单指南》第一层次方法计算的结果对比发现,IPCC方法计算结果(CH4和CO2排放量分别为20 287.39、12 479.74 t,折合CO2当量为519 664.74 t)远高于实测法计算结果,因此,IPCC方法总体上严重高估了我国温室气体排放量.

Greenhouse gas（ GHG） emissions from the process of natural gas development is an important emission source in the fossil energy system.Research on greenhouse gas emissions from the oil and gas system is still in its infancy in developing countries such as China.As a major gas producer,the Sichuan Basin was investigated.A large-scale representative gas field with 160 million m3 was selected to study GHG emissions in the exploration and development of natural gas.Each potential gas leak point among all the components at the stations,such as wellhead,gas gathering station and gas distributing station,was monitored by CH4 concentration detector.In addition,the GHG emissions from gas field water storage in open air water pools and torching were simulated in the laboratory.Combining the simulated and field-measured data,the emissions were precisely calculated in the study area in 2011.The results showed that CH4 and CO2 emissions were 1,033.32 t and 1,295.56 t in the study area in 2011,converted to an equivalent of CO2 of 27,128.56 t.As compared with results determined by the first-level method of the Intergovernmental Panel on Climate Change（ IPCC）（ 20,287.39 t of CH4 and 12,479.74 t of CO2,converted to equivalent of CO2 of 519,664.74 t）,the IPCC＇s result is much higher than the results of field measurement.