油气藏微渗漏甲烷对温室气体的贡献及其排放机理研究

油气藏 微渗漏甲烷 通量评估 温室气体 排放机理
唐俊红 2014-01 项目
Geologic methane microseepage,an important contributor to atmospheric greenhouse gases methane budget, has recently become a research focus of global environmental change. Methane emission fluxes from different types of oil/gas reservoirs were significant difference. The Dawanqi field in Kuche depression (Tarim Basin, Xingjiang Province, China), as a typical shallow oil/gas reservoir, will be selected as the area of study. Firstly, by monitoring temporal and spatial variation of methane emission from the Dawanqi reservoir, emission fluxes of microseepage methane in the shallow oil/gas reservoir will be used for developing prediction and evaluation models.Secondly, based upon our previous methane flux studies of microseepage methane from the deep oil/gas reservoirs in the Tarim Basin, the overall contribution to atmospheric methane budget from the Tarim Basin will be predicted reasonably.Finally,in order to shed some lights on the emission mechanisms of microseepage methane from oil/gas reservoirs with varying geologic features and controlling factors in oil/gas reservoirs,computer simulation method will be adopted to evaluate the processes of microseepage and oxidation of methane in saturated zone and unsaturated zones, by taking into consideration the methane fluxes, environmental soil factors,soil gas composition and isotopic characteris- tics. Successful completion of this study will not only provide an important complement to Chinese and global database of microseepage methane flux, but also lay theoretical foundation for more accurately assessing contribute of natural methane emission flux from oil/ gas basins to atmospheric methane budget.
CH4是地球大气中的主要温室气体之一,其中地质CH4微渗漏对大气CH4源汇的贡献近年来成为全球环境变化研究的热点。不同类型油气藏,其CH4释放通量具有明显差异。在前期评估的深层油气藏CH4通量对大气CH4源汇贡献基础上,拟选择典型的浅层油气藏大宛齐油田为研究区,监测其CH4通量时空变化,建立浅层油气藏CH4释放通量预测方程和评估模型,系统地评估浅层油气藏CH4通量;并结合前期预测的深层油气藏CH4通量,合理地评价塔里木盆地CH4天然释放对大气CH4的贡献。同时,根据油气田CH4通量、土壤环境影响因子变化以及不同深度壤中气组成及同位素特征,针对不同地质构造条件和油气藏分布控制因素,结合计算机模拟方法,研究轻烃在地表的扩散和氧化过程,探索油气藏微渗漏CH4排放机理。研究结果将补充和完善中国及全球微渗漏CH4通量数据库,并为正确系统地评估含油气盆地微渗漏CH4释放对大气CH4的贡献提供科学的依据