加里东古隆起震旦系的烃源条件

通过对震旦系气藏天然气组分的分析和天然气同位素的研究及计算 ,明确认为震旦系的油气主要来自寒武系。又通过对储层沥青和烃源岩中生物标志化合物的研究 (如正构烷烃、姥植比、三环萜烷和五环三萜烷、10 脱甲基藿烷、甲基藿烷 ) ,不仅证实了资阳、威远地区震旦系储层沥青来自寒武系烃源岩 ,而且指出资阳和威远油气的来源是不同的。研究认为 ,广海陆棚相是主要烃源岩分布的沉积相 ,也是四川盆地生烃能力最强、分布范围最广的一套烃源岩。烃源岩的有机质丰度高及类型好 ,且有机质演化具有三大特征 :一是成烃高峰期参差不齐 ,供烃时间长 ;二是供烃中心具迁移性 ;三是三叠纪末是大规模油气生成期。根据TSS烃源岩热模拟评价系统对震旦系、下寒武统主要烃源岩生烃计算结果 ,认为下寒武统烃源岩的生烃强度最大 ,震旦系灯影组较小

THE HYDROCARBON SOURCE CONDITION OF SINIAN SYSTEM OF THE CALEDONIAN PALAEO-UPLIFT

The analysis of composition and carbon isotope of the Sinian natural gas reservoir.indicated that the hydrocarbon in the Sinian System mainly came from the Cambrian source rocks. Detailed research on biomarkers in reservoir asphalt and hydrocarbon source rock revealed that the Sinian reservoir asphalt in Ziyang and Weiyuan came from the Cambrian hydrocarbon source rock and the gas sources in Ziyang were different from that in Weiyuan. Continental shelf was the main sedimentary facies for the development of the Cambrian source rock with the highest source potential and the widest distribution in Sichuan basin. The Cambrian source rock is characterized by abundance and good type of organic matter. Based on the calculation of hydrocarbon generation, it is concluded that hydrocarbon generation intensity of the Lower Cambrian source rock is much higher than that of the Sinian Dengying Formation.