试论不同成因混合气藏及其控制因素

DISCUSSION ON GAS POOLS OF MIXED ORIGINS AND THE CONTROLLING FACTORS

戴金星

Dai Jinxing

石油工业部石油勘探开发科学研究院

Research Institute of Petroleum Exploration and Development, Ministry of Petroleum Industry

天然气具有分子小、重量轻、粘度低和被岩石吸附能力小、运移速度快、扩散能力强、运移途径长等特征,所以聚集在一个气藏或气苗中诸气体组分,除具同一成因外,也有混合成因的.以往仅根据其主要组分的成因,把整个天然气藏统归同一成因,而忽视了不同成因的混合气藏(苗)的研究.近几年来,由于重视了天然气组分的同位素测试,我国有很多气藏(苗)是具有不同成因混合气藏的特征的.

Based on the analyses of various isotopic compositions (δ13C1,δ13Cco2,40Ar/38Ar,etc.),it is suggested there arc not only natural gases of single origin,but also gases of mixed origins.According to the isotopic composition studies of He,Ar and C,the constituents of He,Ar and N2 in Sinian weiyun Gas Field are pertained to inorganic origin coming from deep parts of the crust,whereas it can attributed to thermogenic gas because the isotopic values of the hydrocarbons are of -32.6‰— -32.9‰.As another example,the gas of Wanjints Gas Field has values of δ13Cco2 range from -4.04‰ to -8.83‰ which proves the inorganic origin of the CO2 (volcanic source) whereas δ13C1 value is of -42.07‰ to -45.37‰ which indicates the organic origin of the methane.The various origins of the different constituents of the same gas pool (shows) indicate not only the complex processes for the accumulation and formation of natural gas,but also the complication of the gas and source correlations.

https://doi.org/10.11781/sysydz198604325