Abstract: The authigenic illite in the sandstone reservoir was only formed in the diagenetic phase with mobile K-rich pore water.The entry of hydrocarbon fluid in sandstone reservoir brought a halt to illite forming process,and if the illite can be isolated and its age determined the earlist time of the entry of hydrocarbons can be calculated.The results of K/Ar isotopic chronological analysis which was used to determine two groups of samples showed that the ages of diagenetic illite in Carboniferous sandstone reservoir of D area and Triassic condensate sandstone reservoir of J area in the Tarim Basin were 24.3-31.8M and 44.3-49.2Ma,reflecting that those petroleum reservoirs were formed in the Oilgocene and Eocene respectively.

Key words: authigenic illite, K/Ar isotopic dating, timing of petroleum emplacement, sandstone reservoir, Tasirn Basin

摘要： 砂岩储集层中自生伊利石仅在流动的富钾孔隙水介质环境下才能形成,烃类流体注入储集层后自生伊利石形成便会中止;因此,烃类流体进入储层时间不可能早于自生伊利石的形成时间.利用K/Ar同位素地质年代学方法分析塔里木盆地D区石炭系油藏和J区三叠系凝析气藏二个砂岩储集层的自生伊利石形成时间,分别为24.3～31.8Ma和44.3～49.2Ma,反映油气藏形成期前者为渐新世,后者为始新世.

关键词: 自生伊利石, K／Ar定年, 油气藏形成期, 砂岩储层, 塔里木盆地